CLIMA 2016: 12TH REHVA WORLD CONGRESS: CLIMA 2016
PROGRAM FOR WEDNESDAY, MAY 25TH
Days:
previous day
all days

View: session overviewtalk overview

08:30-10:00 Session Keynote Lecture

Dr. Brian Motherway, Head of Energy Efficiency Division, International Energy Agency

Lecture:
The IEA is an autonomous organisation which works to ensure reliable, affordable and clean energy for its 29 member countries and beyond. The IEA has four main areas of focus: energy security, economic development, environmental awareness and engagement worldwide. Rooted in its broad expertise across the entire energy system, and supported by its rich data and analytical capabilities, the IEA is a leader in global analysis of the impacts and implications of energy efficiency policy, offering guidance on how to design and deliver energy efficiency policies and programmes.

Biography:
Dr Brian Motherway is Head of the Energy Efficiency Division at the International Energy Agency, overseeing a range of analytical and outreach programmes supporting energy efficiency globally. Prior to joining the IEA Brian was Chief Executive of the Sustainable Energy Authority of Ireland. Brian holds Bachelors and Masters degrees in engineering and a PhD in sociology.


Geo Clausen, Professor, Head of Section, Technical University of Denmark

Lecture:
What did you learn in school today? – A concerned look at indoor environment seen from a child’s perspective

Biography:
Dr. Geo Clausen is Professor at The International Centre for Indoor Environment and Energy at the Technical University of Denmark. He received his Ph.D. from the Technical University of Denmark in 1986 and has since then studied various aspects of the impact of the indoor environment on human comfort, health and productivity. Recently his research has focused on the indoor environment that children at all ages experience and the effects this have on their health, comfort and learning.

 

Location: Hal Øst
10:30-12:00 Session SS 10: Sustainable Energy
Location: Det Lille Teater
10:30
Biomass-based heating and hot water supply systems for prefabricated, high energy performance houses: a comparison of system configurations and control strategies
SPEAKER: Elisa Carlon

ABSTRACT. Nowadays prefabricated houses are becoming increasingly popular, thanks to their low cost and high energy performance. These houses are often equipped with heating and hot water supply systems based on renewable energies. In particular, systems combining pellet boilers and solar collectors are widespread in Central Europe. Such systems should be carefully designed and controlled, to ensure sufficient thermal comfort while maintaining low fuel consumptions. In this regard, dynamic simulation tools can be used to find optimal system solutions. This study presents the simulation of different system configurations and control strategies for a pre-fabricated house. The house was monitored within a European Project (BioMaxEff), aiming at the demonstration of biomass boilers in real life conditions. The prefabricated single family house is heated by a 6 kW pellet boiler directly connected to a floor heating system, in a configuration without buffer storage tank. Hot water production is supported by solar collectors installed on the roof. The heating system is controlled by a thermostat located in the living room: the indoor temperature is set to 21 °C, with a night setback to 18 °C. Using the TRNSYS simulation suite a coupled simulation of the house and its heating and hot water supply system was set up, calibrated and validated with reference to monitoring data (indoor temperature profiles and monthly pellet consumptions). Monitoring data evidenced that the control strategy of the heating system is not ideal to maintain a comfortable indoor temperature during the whole day. Therefore, two improved strategies were simulated over the heating season and evaluated in terms of thermal comfort, pellet consumption and boiler efficiency. Simulations results showed that the elimination of the night setback temperature maximizes the thermal comfort, together with a limited increase of the pellet consumption (45 kg), and a small (0.4%) increase of the boiler’s efficiency, due to the long operation cycles at nominal load. Moreover, to better understand the influence of the system configuration, simulations have been repeated considering another heat distribution system (radiators instead of floor heating). Results show that the radiators’ network, if adequately controlled, provides a higher thermal comfort. In addition, the pellet boiler mainly operates in load modulation regime, leading to lower pellet supply rates and therefore to lower pellet consumptions (18% less than floor heating). However, the lower operational loads and frequent ignitions reduce the boiler’s efficiency of 4%. In conclusion, this study demonstrates an application of dynamic building simulation to test different control strategies and system configurations. It was concluded that, for pre-fabricated houses, heat distribution systems having a fast time response ensure higher thermal comfort and lower fuel consumptions, but they have to be carefully controlled, in order to maintain the efficient operation of the boiler.

10:40
Exploring the novel software Hysopt: a comparison of hydronic heat distribution systems of an apartment building

ABSTRACT. Space conditioning and domestic hot water production in buildings account for a large amount of the global primary energy consumption. The type of system that supplies the demanded energy can affect this energy consumption. This paper considers two types of systems that are used in apartment buildings. In the first system, each apartment unit supplies its own heat using a combi boiler (individual production system or IPS). In the second system, the heat is produced by a central boiler (the central production system or CPS). Pipes circulate the water and substations connect apartment units to these pipes. While the CPS facilitates the implementation of sustainable energy sources, it also loses energy due to the distribution circuit. Therefore, a comparison between these two systems seems necessary. This paper compares an IPS and a CPS within an apartment building. This comparison is based on simulations, using the software ‘Hysopt’. Results show that the CPS scores 6.9 percentage points lower on efficiency, compared to the IPS. However, the number of startups per boiler is 3.3 times less for the CPS (which has only one boiler while the IPS has 11). This system also shows a higher controllability. Some further steps should be taken to complete the comparison, as the results of the energy consumption are questionable.

10:50
Experimental analysis of a gas micro-cogeneration based on internal combustion engine and calibration of a dynamic model for building energy simulation
SPEAKER: Pierre Picard

ABSTRACT. Micro-Combined Heat and Power (µCHP) is an innovative technology for distributed electricity production (power rating below 50 kWel). Internal combustion engine (ICE)-based micro-cogeneration is a mature technology covering a wide range of capacities and recent developments increased the efficiency through condensing exhaust device and variable speed pumps. This type of equipment is suitable for residential and small commercial buildings and is usually integrated in a system with back-up boiler. Design issues are the proper sizing of each equipment, their controls, the need for thermal storage, the economic impact of new tariffs (feed-in vs self-consumption), the potential of flexibility in a smart grid, etc. A dynamic model is suitable to investigate various types of applications. That is why a generic grey-box model was previously developed with few and easily accessible parameters. It has already been used to represent Stirling Engines with success. This paper deals with parameterization of the same model for an ICE.

The first step of the present work aims at characterizing this ICE-based µCHP experimentally and model its dynamics for heat and electricity production. The unit develops an electrical power of 7.5 kW, a thermal power of 20 kW and is mounted on a test bench. The test facility and its main characteristics are described in the paper and an uncertainty analysis is led to evaluate the uncertainty of the measurement chain

In order to characterize the performances and operation of the ICE-based µCHP, static controlled boundary conditions are set for various inlet water temperatures and electrical power setpoints. Dynamic operating conditions are also analyzed to measure gas consumption, electrical and thermal production during start-up and shut-down of the µCHP to take these operating states into account in the model.

The static and dynamic parameters of the grey-box micro-cogeneration model are thus identified with the collected experimental data for all operating conditions. The errors on the simulated performances are assessed.

The grey-box model calibrated thanks to the experimental dataset will be used, in the future, to undertake building energy simulation studies in various cases like collective housing, commercial buildings, hotels and others to identify optimal integration of this µCHP system.

11:00
Renewable Urban Heat Supply for Domestic Housing in the City of Vienna
SPEAKER: Peter Holzer

ABSTRACT. Introduction: Vienna is a rapidly growing city with an an estimated yearly need for 8.000 new flats. Simultaneously the Viennese municipality passed the Smart City Vienna Framework Strategy in 2014, fixing reduction targets for CO2-emissions and primary energy consumption for 2050. In a joint effort of Austria’s dissemination program renewable heat supply and Vienna’s municipal department 20 energy-spatial-design and Vienna’s energy agency both basic and applied research is recently carried out to develop options of renewable heat supply of newly built urban residential settlements, which the authors are deeply involved in.

Methodology: 1) The Smart City Targets of max. 1 ton of CO2 emissions per year and capita and of max. 2.000 Watt primary energy demand per capita have been broken down to the sector of domestic housing, based on literature research and eco-balance-calculation. 2) The most relevant parameters of influence have been identified and have been fed into an Excel-based scenario-tool, being now used for further scenario-analysis. 3) Outputs of 1 and 2 have been applied to exemplary conceptual energy supply design for two actual urban site-developments of 300.000 resp. 750.000 sqm net floor area. The conceptual design was carried out by means of applied research and integrated design, including international experts, learnings from other cities+projects, including representatives from municipality as well as the property developers. Basic concepts are now ready for detailed design, already containing technical solutions as well as ecological and economic performance indicators.

Results and Discussion: 1) To reach the urban aim of max. 1 ton CO2 per person and year and max. 2.000 Watt primary energy demand per person, the sector of domestic housing may use 0,46 tons CO2 and 500 Watt primary energy demand. 2) Four parameters have been identified which subsequently form the CO2-emissions and primary energy demand per person: a) net-floor-area per person, b) energy demand per floor area, c) the mix of energy carriers applied d) the supply-technology of the energy carriers. An Excel based scenario-analysis-tool was developed and may be presented. 3) Based on feasibility studies including on-site and off-site renewable energy resources the following concept turned out promising: - Nearly-Zero-Energy-Buildings, - with strictly Low-Temperature-Floorheating (optionally with cooling), - with heat supply from large heatpumps, fed from fields of borehole-heat-exchangers,thermally recharged from renewable all-year-heat-sources, possibly even recharged from urban district heat supply, which then can be used most efficiently from the return flow only and with significantly better balanced peak loads.

Conclusion: Comprehensive design studies, including learnings about obstacles and shortcomings, are available and may be presented and discussed frankly.

Acknowledgements: The research offered for presentation has been financially supported by both The Austrian Federal Ministry of Agriculture, Forestry, Environment and Water Management within the klimaaktiv program renewable heat and by the municipality of Vienna, municipal department 20 energy-spatial-design.

11:10
Cold Water Heat Networks and the Thermal Storage Revolution
SPEAKER: Andy Ford

ABSTRACT. Improving the way we heat and cool buildings is a key part of decarbonising future cities. The thermal performance of modern buildings is driving down the demand for space heating per unit. Commercial buildings are already typically cooling led and this trend is accelerating. The challenge is how to thermally link up buildings to make best use of their fluctuating need to both add and remove heat to achieve comfort seasonally as well as day by day. The Department of Energy and Climate Change has the stated goal of delivering 15-25% of the UK’s space and water heating demand through heat networks. Current capacity is estimated at 2%. Developing scalable solutions to heat networks is therefore critical to meeting energy demand, and to reaching the UK’s 2050 carbon reduction targets. This paper will present evidence that rather than build district heating schemes, ‘Cold Water Heat Networks’ (CWHN) linked with seasonal storage provide a better solution. Cold Water Heat Networks transfer heat at ground temperature and extract it via heat pumps, which allows the integration of diverse energy systems through links to boreholes and other storage, the recovery of low grade waste heat, and the delivery of simultaneous heating and cooling, none of which are possible with conventional heat networks. This paper gives the results of a feasibility study for this technology that has been conducted at London South Bank University and shows the carbon and cost reduction potential of installing such a network in a central urban area. The analysis considers retrofitting a simple network linking two existing buildings. The performance of the network is measured against a business as usual scenario (existing gas boiler systems). The metrics considered include life cycle cost, carbon savings, and return on investment. The paper details the assumptions made for each scenario and shows that the CWHN performs better against every indicator. Furthermore it finds that efficiency increases with the scale of the network. The paper closes with an analysis of the barriers to scalability based on a workshop that has been held with industry and government stakeholders. The paper finds that by embracing the growth in cooling demand and choosing distribution temperatures to enable cooling and optimise heat pump performance from a single network, we could with good planning significantly reduce the amount of refurbishment that needs be carried out over the next 35 years. CWHNs can revolutionise heat transfer and storage for buildings. Building services will no longer be about creating heat, but about moving heat away from places that need cooling towards places that need heating. Not heating and cooling generation, but thermal storage and management. CWHNs will open a new frontier of innovation in technologies to add, move, and remove energy from a network.

11:20
Investigation of a Small Scale Wind Turbine-Heat Pump Hybrid System for a Detached House

ABSTRACT. Heat pumps are widely used in order to meet cooling and heating needs of residential buildings and houses. Even if the thermal energy supplied by heat pumps is greater than the electrical energy they consume, a great amount of annual electricity consumption is present for the operation of such devices. Although the electricity consumption of these devices decreases as their efficiency (COP) value increases, the source of the electricity they consume is a major problem. If all or a portion of the electrical energy consumption can be covered from renewable energy resources, the emission of greenhouse gases, produced in electricity generation using conventional plants, may be lowered. In the present study, a 100 m2, single storey, detached residential house in Bornova region of İzmir, Turkey is considered. The monthly and annual heating and cooling energy need values of the house, performed using Energy Plus software, is taken from a previous study. The electricity consumption of a selected ground source heat pump (with a COP value of 4 in heating and 3 in cooling), which will supply the necessary annual cooling and heating needs of the house, is calculated. A small scale wind turbine is taken into account in order to generate the required electricity consumption of the heat pump. Finn Wind Tuule E200 wind turbine is selected in the study because of its smaller cut-in and rated wind speed values, which enable a high capacity factor value. In order to calculate wind turbine annual electricity generation value, monthly Weibull distribution function parameters, derived in another study performed for Bornova region, are used. Consequently, estimated monthly and yearly electrical energy generation amount of the wind turbine for the region is calculated. As the result, it is estimated at what level the heat pump electricity consumption can be covered using the selected small scale wind turbine. The results indicate that the total annual electricity consumption of the heat pump is 4541.67 (kWh) and a great percentage (about 68.9%) of this electrical energy need can be supplied by the selected wind turbine.

11:30
ASPECTS REGARDING ENERGY CONSUMPTION

ABSTRACT. This paper approaches topical issues regarding energy supply and consumption, highlighting the sources, the major factors to be harmonised and offers solutions regarding the means of approach in choosing the energy source/ system as well as its sustainability.

Key terms: energy efficiency, sustainability.

Introduction All human activities are energy consumers. We might say that nowadays society is ”powered” by energy and follows the general equation:

CE = ECCN + TESD (F) + RLCC + LOG (1) Where: CE = Consumed Energy ECCN = Energy Covering Current Needs (for everyday life) TESD(F) = Technical, Economic and Social Development (for the Future) RLCC = Raising the Level of Civilisation and Comfort LOG = Love of Gain

It is no longer a secret that ”In order to exist, the world needs energy to use (only) for peaceful purposes”. However, the reality of our days shows us another facet as well, described as:

IER ∩ IUR ∩ GWR → CRISIS (2) Where: IER = Irrational Exploitation of Resources IUR = Irrational Utilisation of Resources GWR = Generalised Waste of Resources

This way of approaching existence, translated by the need to ensure permanently the necessary energy, given the general progress, but also to ensure a durable development, is of recent date. In 1983 the United Nations established the World Commission on Environment and Development – WCED, that stated that ”durable development is the one that ensures the needs of the present without compromising the possibility of future generations to satisfy their own needs WCED also stated that: - ”development does not mean high profits and improved living standards for a small percent of the population, but the raising of living standards for all”, - ”development should not imply the destruction or reckless usage of our natural resources, nor the pollution of the environment.” The reality nowadays shows a couple of major inconvenient aspects such as and changes. The major contribution to the current situation belongs to the human being. In consequence, it is the task of the human being to remedy the situation, by acting responsibly and honestly.

Final considerations

Real life is based on market economy and governed by laws which, for the aspect regarding energy for buildings and afferent installations, need coherent and responsible strategies and policies, designed to ensure the environment protection, ambiental comfort, efficient and sustainable use of energy – despite all partisan interests. Singular and local, pinpoint approach of a problem in energy and especially extrapolating it without analysing the general context – upstream and downstream – may lead to serious mistakes and irreversible errors. In order to ensure the energy needed for all human activities we must use every source available, with the condition of harmonising all elements: social, economic, ecologic and guaranteeing sustainability. Energy is vital for constructions/ buildings and there are real possibilities to reduce consumption, save energy, ensure comfort and protect the environment. The means and techniques exist, all we have to do is put them into practice with professionalism.

11:33
The Application of Combined Renewable Energy Systems in Smart Buildings
SPEAKER: Marek Kusnir

ABSTRACT. A team from Technical University of Kosice (TUKE) has in the last years created a new high profile project called VUKONZE, which is a Slovak acronym for a Centre for researching the effectiveness of integrating combined systems of renewable energy sources, financed by the Ministry of Education of the Slovak Republic, and the European Regional Development Fund. This progressive project in the area of Civil Engineering is orientated towards the integrated design of intelligent systems in building service technology environments and renewable energy sources based on the synergistic combination and development of the following goals: - The development of modern technology system environments made of advanced materials with the use of modern terminal and distribution elements and their application in real terms - The creation of non-linear time-dependent transformations of calculation models in order to assess changes in time-variable properties of building structures and their environmental status - Verification of physical characteristics of the in-situ internal environment in real conditions; exploitation for the purpose of application in simulation methods - Creation of regulatory, management and control methods for complex systems in environmental engineering - The conversion of the building’s energy supply from fossil-based fuels to locally accessed renewable resources - The creation of models to transform buildings into zero net energy balance structures - Preparing conditions for the transfer of technology and its inception in R&D innovations in Slovakia. The paper outlines the concept for the implementation of coupled renewable energy sources and their operation. The output is a proposal to motivate the energy market and building industry, through recommendations, economic viability and legislation, to reduce their dependency on fossil based fuels. This achieved by defining the most appropriate renewable energy source combinations, their application optimized operation in practical implementations.

11:36
TECHNOLOGY ASSESMENT IN A FUTURE CROSS SECTORIAL HEAT AND POWER MARKET

ABSTRACT. What heating and cooling technologies will be found in a future cross sectorial heat and power market? To achieve the emission targets set by the German government for 2050, wind and PV are the main pillars of the energy system. These power production technologies are cost efficient, do have a high development potential and therefore can provide power not only for the conventional power, but also for the heat and also for the mobility sector. The project is focused on the requirements and challenges that need to be managed to achieve an efficient sector coupling. Therefore a simulation platform has been established to find cost optimal technology solutions, both on the side of energy production (Wind and PV technologies) as well as on the side of energy end use (e.g. for the heating of buildings) based on the different political targets and boundary conditions. A wide range of technologies are integrated via key performance indicators into this platform. In turn this platform offers the possibility to assess existing and also possible future technologies based on their capability to offer a cost efficient solution in that future market situation. Only that cost efficient solutions will be found in a market on the long run. The paper presents the outcome of the German national funded project on “Interaction of renewable power, heat and mobility - Analysis of the interaction between the power, heat/cold and mobility markets in Germany regarding increasing shares of fluctuating renewable energies and in consideration of European market development”. The authors acknowledge gratefully the financial support given by the German Federal Ministry for Economic Affairs and Energy (BMWi).

11:39
Integrated ground source heat pumps and solar thermal systems for zero energy buildings
SPEAKER: Clara Good

ABSTRACT. INTRODUCTION This paper presents a comparative study of different integration strategies between ground source heat pumps and solar collector system, aimed at enhancing renewable energy sources exploitation to provide space heating and domestic hot water to a net zero energy building. The case building is the Living Lab, built by the Norwegian Research Centre on Zero Emission Buildings (ZEB) and located in the campus of the Norwegian University of Science and Technology (NTNU) in Trondheim, Norway.

The building has around 100 m2 heated floor area, and a total south-facing roof area of 80 m2 with 30° tilt angle. A grid connected photovoltaic (PV) system is installed on the full roof area, with a rated power of 12.5 kWp. Thermal energy is provided by a combination of 4.2 m2 façade integrated solar collectors and ground source heat pump with a surface collector field (at around 1.5 m depth and 100 m in length). Different heat distribution systems exist in the building for experimental purposes, but only the underfloor heating system considered for this study.

METHOD The effectiveness of this different concepts are investigated through numerical simulations, performed in Polysun from Vela Solaris. This is a dynamic simulation tool for thermal and electric solar energy solutions systems, as well as for hydronic systems and other building equipment components. The heating and DHW loads are and obtained from previous publications, and used in combination with hourly user profiles.

Two types of configurations between the heat pump and the solar thermal collectors are studied: a) Separate connection to the tank, i.e. working independently from each other b) Integrated connection

In the second case, the system can work in different modes depending on the temperatures of heat transfer fluids in the hydronic circuits. The solar thermal output can be used to directly load the storage tank, or as a direct input to the heat pump; the thermal output from the surface collector field can be post-heated before it feeds the heat pump; and finally, the solar thermal output can be used to recharge the ground during summer, when the heating demand is low.

RESULTS The results show that the thermal output in kWh of the solar collectors is increased by 33% when the integrated connection is used. The solar fraction is increased from 14% to 18% under this configuration. The percentage increase in output is largest during January, June, November and December, in the range 40% to 50%. In absolute values, the largest increase is seen in summer. The temperature heat transfer fluid in the solar thermal panel circuit is significantly lower when the integrated connection is chosen than when the two systems are independent, with positive consequence on the efficiency of the solar thermal system.

DISCUSSION This study shows that an integrated configuration between the heat pump and the solar thermal system is beneficial, and results in an increase in energy output and a better overall performance of the system.

11:42
Simulation study of heat recovery from flat roof photovoltaic systems by mechanical ventilation for a wine warehouse in France

ABSTRACT. The integration of solar energy systems into industrial building roofs represents a practical solution to reduce the carbon footprint of this sector through both grid feed-in and self-consumption strategies. In France in 2012, industrial and commercial zones accounted for approximately 0.7% of the total metropolitan land mass, equivalent to 3.8x103km². Horizontal rooftops included within this figure could represent a significant fraction of the current total photovoltaic capacity of the country, whilst offering the advantages of typically large individual rooftop areas and a daytime load profile of some industrial buildings which may favour onsite consumption of solar energy. Where local demand exists, additional gains may then be made by installing hybrid photovoltaic-thermal (PVT) systems. The choice of integration strategy must necessarily depend on the specific heating and cooling needs of each types of building. At present this diversity of application represents a bottleneck to technology development, as it hinders estimates of market potential.

In this paper we consider the specific potential of space heating and water preheating for the case of a wine warehouse in southern France, equipped with an iNovaPVT system developed by EPC Solaire. The key features of this product include a horizontal arrangement of conventional PV modules, and a novel metal structure that serves both as mechanical support and ventilation duct. In the warehouse the air temperature is maintained at 14-18°C throughout the year, and has a low demand of hot water for cleaning. The load profile of the building is strongly affected by the presence of the wine stored in vats, which represent a large internal thermal mass.

Simulations were performed with TRNSYS, using bespoke Types for iNovatPVT components. The solar collectors were modelled by a stack of 1D nodal network of resistive elements forming slices along the direction of air flow, and the resulting linear system of equations was solved analytically. The test setup corresponds to a prototype installation constructed near Orange, France in 2015, and co-financed by ADEME, the French environment agency. System performance was calculated for standard Meteonorm years under air preheating and hot water generation configurations. The potential for air preheating was assessed by comparison to the enthalpy requirements of the building under typical operating conditions. The study served to reveal those periods of the year where each form of heat recovery would be useful. The predicted potentials for airspace preheating and hot water generation were found to be complementary in this regard, with hot water generation proving interesting during the portion of the year where the heating load of the building is negligible. Sensitivity of system performance to weather conditions is highlighted, and in particular the impact of wind on panel heat dissipation. In conclusion, the potential for self consumption is assessed for the case in study.

11:45
Thermal Analysis of a Flat-Plate Solar Collectors in Parallel and Series Connections

ABSTRACT. In this study, thermal analysis for solar collectors in series and parallel connection was conducted, taking into consideration a model for flat-plate solar collectors with fluid. A model of thermal analysis made up of dimensionless numbers was set up and by the help of computer software, generally accepted graphics for the dimensionless temperature, dimensionless solar radiation, coefficient of thermal efficiency were obtained. Making use of these graphics, numbers of collectors can be determined for the desired values of flow rate and temperature.

11:48
Evaluation of On-site PV-based Electrical Energy Production: a Case Study
SPEAKER: Luca Zaniboni

ABSTRACT. On-site power generation by photovoltaic systems can be a possibility for sustainable electrical energy supply. For this purpose, it is important to evaluate the potential based on the location, the technical solutions available on the market and also the economic aspects. The present research analyses all those factors for a case-study commercial building in Vienna, Austria, whose findings can be applied to all those building configurations operating in similar contexts. In a first step, the energy consumption of the facility was analyzed in detail. Based on the outcome, different cases of optimization of power generation and retrofitting of power consumption were developed, focusing on the lighting system. Furthermore, various scenarios of PV-system design were evaluated via simulation, covering different fractions of the electricity need. The adoption of local electricity storages (i.e., batteries) was considered as well. The results show that designing PV systems for covering the base load is more convenient than retrofitting the entire lighting system. Moreover, it was demonstrated that, due to current Austrian practice regarding pricing of PV-generated electricity, overproduction does not pay off, even though it has the potential to reduce the CO2 emission of buildings.

11:51
The Effect of Reducing Supply Temperature in Fourth Generation District Heat Networks on Design of In-house Heat Substations

ABSTRACT. Lowering the district heating supply temperature is crucial for improving the efficiency of the heat network. A recently developed concept of the fourth generation low temperature district heating with supply temperature just above the required secondary conditions allows for heat loss reduction, increases the plant room efficiency and enables the integration of alternative energy sources for energy production. This paper aims to determine the requirements and constraints for increasing the efficiency of in-house heat substations to enable the implementation of next generation heat networks. Heat transfer calculation software tools are used to analyze the impact of the domestic hot water peak capacity, cold and hot water temperatures, district heating flow and return temperatures and pressure drop limitations on the design of in-house heat substations. Challenges associated with low primary temperature have been identified in this paper from the perspective of in-house heat substation performance, comprising the increase of primary flow rate due to lowered primary temperature difference, and therefore the pressure drop across the components. It is concluded in this paper that by utilizing the plate heat exchanger technology available, it is achievable to design and implement heat substations that are capable of producing instantaneous domestic hot water at safe temperatures with minimized approach flow temperature to 3-5°C.

11:54
Double Skin Façades Integrating Photovoltaic Panels: A Comparative Analysis of the Thermal and Electrical Performance

ABSTRACT. A numerical model is developed for simulating a single or multi–story Double Skin Façade integrating Photovoltaics (DSF-P). The proposed model enables the prediction of the thermal and electrical performance of the DSF-P system. The DSF-P can co-generate solar electricity and heat. The buoyancy-driven air flow inside the cavity may be assisted by a fan to cool down the photovoltaics while providing natural or hybrid ventilation to adjacent zones. Automated roller shades are also implemented in the model, which help regulate heating and cooling loads but also control the daylight levels in the indoor space. A comparative analysis for two different climate zones, Montreal (Canada) and Naples (Italy), is performed with the purpose to apply the proposed methodology for the optimization of the DSF-P system in different climate regions. The simulations show that a DSF-P system integrating photovoltaics can supply approximately 0.20kWh/m2/day of solar electricity to the adjacent office space providing between one-third and one-half of the daily thermal energy demand of the office (cooling and heating). In addition, during the heating period for a three-story DSF-P, the temperature difference between the inlet and the outlet of the cavity can reach up to 18oC giving the opportunity for natural or hybrid ventilation to the building.

11:57
Towards Developing An Exergy Management System Standard and Its Application to a University Building
SPEAKER: Arif Hepbasli

ABSTRACT. In June 2011, the International Organization for Standardization (ISO) released ISO 50001, Energy Management Systems – Requirements with guidance for use while EN 16001, the European standard for Energy Management Systems, was issued in July 2009. The ISO 50001 standard advocates continuous improvement of energy performance (energy efficiency, energy consumption and energy use) and provides requirements for an energy management system (EnMS) for achieving this continuous improvement. Exergy can be considered to be one of the key issues for sustainability. Exergy analysis has been widely used by many investigators and practicing engineers as powerful tools for analyzing, assessing, simulating, designing, improving and optimizing systems and processes. Benefits of exergy analysis are numerous, especially compared to energy analysis. The exergy concept is useful to pinpoint magnitudes and locations of thermodynamic imperfections occurring through an energy supply chain. The main idea behind establishing an EnMS structure is based on the energetic performance improvement in a continuous way while exergy analysis helps deduce the areas for possible improvements in any energy system. The main objectives of this study are twofold, namely (i) to propose a new exergy management system (ExMS) standard for the first time in the open literature to the best of the author’s knowledge by explaining how to develop, and (ii) to briefly apply the milestones of the proposed standard to a campus building of Yasar University located in Izmir, Turkey, which achieved TS EN ISO 50001:2011 certification as the first university in Turkey on 5 January 2016.

12:00
Impact of using solar heat pumps for domestic hot water in Portuguese residential buildings.
SPEAKER: Olga Castro

ABSTRACT. In recent years, we have seen an improvement of existing facilities in dwellings in Portugal. Within the heat pumps systems, there is a special type known as direct expansion heat pump assisted by Solar Collector (DX-SAHP). It was calculate the SPF indicator for 30 regions of Portugal. It was analyses the potential of reductions of CO2 and primary energy use for the retrofitting of DHW preparation systems. It was found that the performances of this type of equipment are benefiting from the Portuguese climate conditions, especially in the South and in the Autonomous Regions. Best SPF was obtained for Beja. It was found in all regions of the high potential for reducing CO2 emissions and verifying a potential significant reduction of primary energy consumption.

12:03
“Use of alternative water sources based on a rainwater in the multi-dweling Urban Building 2030”
SPEAKER: Monika Lipska

ABSTRACT. Abstract Drinking water is water with a very high quality, and as such represents only 2.5% of the total quantity of all water in the world. For many years we have observed continuous increase in its consumption as a result of many factors such as: growing world population (7 billion in 2011r.), increase of human lives comfort and – above all – the economic growth. Due to the rocketing consumption and growing costs of production of water with such high quality parameters, we experience accelerating interest in alternative sources of obtaining potable water. One of the ways of saving this valuable material is using rainwater in the Urban Building. With an exponentially growing demand, the acquisition of additional sources of water is necessary to maintain the proper balance of all ecosystems. The first part of the paper describes what rainwater is and what are its potential sources and means of use, while the main part of the article focuses on the description of the methods of obtaining water from rain on the example of new urban building in Poland. It describes the method and installations of rainwater in the new urban building (“MBJ2030”). The paper addresses also the issue of monitoring of the whole recycling systems as well as the particular quality indicators important because of identification of the potential risks to human health. The third part describes the legal arrangements concerning the recycling of rainwater existing in different European Union countries with particular reference to Poland on example the new urban building in Warsaw.

1. Introduction 2. Alternative sources of water in the building 3. Recykling rainwater and re-use in sanitary installations 4. Example description of rainwater in multi-dweling Urban Building 2030 Poland 5. Laws in Poland 6. Summary

10:30-12:00 Session SS 14: Energy Flexibility & Storage
Location: Hal Øst
10:30
Numerical simulation of thermal energy storage with phase change materials in aluminum foam
SPEAKER: Oronzio Manca

ABSTRACT. Solar energy represents today an important option in energy use and it presents some fundamental peculiarity such as the absence of environmental pollution, a long term availability and a free energy source. However, one of the main drawbacks is the discontinuity of its supply. This problem can be solved by means of thermal energy storage systems (TESS). There are three types of TESS, chemical energy storage system (CESS), sensible heat thermal energy storage system (SHTESS) and latent heat thermal energy storage system (LHTESS).The latest is the best choice to increase the energy efficiency because it gives the possibility of storing energy at a quasi-constant temperature with very high energy stored density values. The main aim is sizing and optimizing the LHTESS to achieve the best possible solution taking into account also the thermal energy charge and discharge times during the storage. A numerical investigation on LHTESS based on a PCM is accomplished. The PCM used is a pure paraffin wax having a process melting over a range of temperature and a high latent heat of fusion. However, its thermal conductivity is very low (about 0.2 W/K m) and a method to enhance the heat transfer is putting the PCM into an aluminum metal foam. The geometry of the system under investigation is an enclosure with foam and tubes. The internal surface of the tubes are assumed at a constant temperature above the melting temperature of the PCM to simulate the heat transfer from a hot fluid. The external surfaces of the enclosure are assumed adiabatic or with heat losses toward the external ambient. A numerical model is employed to simulate the behavior of the PCM embedded with the metal foam. The phase change of the PCM is modeled with the enthalpy porosity theory while the metal foam is considered as a porous media that obeys to the Darcy-Forchheimer law. The momentum equations are modified by adding of suitable source term which it allows to model the solid phase of PCM and natural convection in the liquid phase of PCM. Local thermal non-equilibrium (LTNE) models is assumed. The governing equations are solved employing the Ansys-Fluent 15 code and verification and validation analysis are accomplished. Numerical simulations for PCM, PCM in the porous medium are obtained and their results are compared in terms of melting time and temperature fields. Results as a function of time for the charging phase are carried out for different porosities and assigned pore per inch (PPI). The results show that the presence of metal foam improves significantly the heat transfer in the LHTES giving a very faster phase change process with respect to pure PCM, reducing the melting time more than one order of magnitude. In addition, this numerical model can be further enlarged to simulate different types of metal foam and PCM.

10:40
Annual operation of LHT storage system for offices
SPEAKER: Uros Stritih

ABSTRACT. This article presents operation of latent heat storage unit with phase change materials (PCMs). Such kind of system reduces energy consumption in buildings since it stores cold during summer nights and delivers it during the day and thus reduces cooling load. In winter system is connected with solar air collector and heat is stored for heating during morning and evening hours. Proposed is a stand-alone unit suitable for offices, which consists of plates filled with paraffin RT22HC. The objective of the paper is to examine the functioning of the suggested TES system on an annual basis, to explore the feasibility of using it for both, cooling and heating and to carry out parametrical analysis in order to find the best set of parameters for given conditions. Heat transfer from and into PCM is simulated with Ansys Fluent code for 2D geometry, temperature of warm air at the outlet from solar air collector is calculated in Trnsys, TRY for Ljubljana (Slovenia) is taken as a boundary condition. Results are compared to energy demands of a typical office (calculated in Trnsys) for Slovenian climate. Calculations reveal that in winter the largest savings are in March, as larger quantities of heat are available at that time. In summer, the maximum amount of accumulated cold is in July and August, because of larger temperature fluctuations between day and night.

10:50
Hot water tanks : how to select the optimal modelling approach?

ABSTRACT. There is a rising interest for optimal use of thermal energy storages (TES) in buildings for load shifting in demand response programs and to improve energy efficiency. In this context, a state of the art of the different methods for simulating sensible TES is performed. Mathematical equations which describes the processes occurring in the storage are difficult to solve without considerable simplifying equations. That is the reason why a large number of storage models have been developed in the last decades. Few studies compare the different modeling approaches and their respective advantages and limitations. A review of the literature is thus performed and focuses on eight different modeling approaches. The comparison is performed in terms of computational time, accuracy and application. A tree of selection is proposed to select the optimal TES modeling approach for a given application.

11:00
Integration of Thermal Energy Storage Components with Buildings – Recent Development and Challenges
SPEAKER: Wonjun Choi

ABSTRACT. The main drawback of renewable energy sources is the variability and intermittence in their availability; causing significant mismatches between the time of energy demand and energy production. To make these future energy sources and conversion technologies a viable solution, it is necessary to use significant levels of energy storage technologies that enable matching of supply and demand. Energy storage technologies play a crucial role in designing and operating high performance sustainable buildings and districts, and are definitely needed for the efficient use of renewable energy resources by dealing with the intermittency of energy supply and demand. However, there is still a distinct lack of guidance on the effective integration and operation of thermal energy storage at the building or district levels. The paper first gives an overview of the most recent development in modelling and validation of the energy storage system/components and its integration with buildings: It covers both active and passive technologies. The abilities and limitations of each technology for the integration, and the challenges of coupling of the model with energy simulation programs are also discussed. Based on these insights, the corresponding technological problems and future research directions for their applications are also described.

11:10
Design and dynamic simulation of a Compressed Air Energy Storage system (CAES) coupled with a building, an electric grid and a photovoltaic power plant.

ABSTRACT. In general, the development of renewable energy such as solar and wind technology is difficult due to its intermittency and its variable character. In an unconnected area such as Reunion Island (a French island situated in the Indian Ocean, at the east of Madagascar), the development of large scale solar photovoltaic power plants directly connected to the power grid may create instabilities. For the same reasons, it is difficult to supply a building only with intermittent electricity sources. Then, making the large-scale integration of photovoltaics power plant for the decentralized electricity grids become a real challenge. Dealing with these issues, one of the solutions for a deployment of intermittent sources such as solar photovoltaic is the integration of an energy storage system. However, the most common technology is based on the use of lithium-ion batteries, which remains not environmentally friendly. A Compressed Air Energy Storage system (CAES) appears as a solution to this disadvantages. It consists in storing the air at high pressure in a tank during the period where the energy source is abundant, cheap or if the energy demand is low. This air is expanded later through an air turbine to provide electricity during period of high demand or lack of the energy source or if the electricity become very expensive. Nowadays, the Compressed Air Energy Storage system technology is mainly used in the case of high power (hundreds of megawatt). The storage can take a long time (around a month) for filling the air vessel, which is most often an old cavern of salt or coal. In order to evaluate the Compressed Air Energy Storage system feasibility coupled to a photovoltaic plant and a building, with a reduced power demand, a model that reflects the instant behavior of the system composed of the photovoltaic plant, the air compressor, the storage and the expansion module, the power grid and a building (consumer of electricity) has been built. The inputs that are used are on one hand the climate’s parameters such as ambient temperature and the solar global irradiation in this particular tropical area and on the other hand the load curve of an administrative building from our University and implanted in the same area. The dynamic simulations allows us to estimate the overall performance of the system, the energies involved in this system, and the coverage ratio due to the stored system over different time basis such as . To assess the influence of each part of the system, a sensitivity analysis on key parameters such as the volume of the air tank, the size of the photovoltaic field and the displacement of the compressor is performed and the results are presented in this paper. In the end, the model allows us to evaluate the optimal size of these components by minimizing the electricity sold and bought so as to approach autonomy thanks to the storage system.

11:20
Thermal evaluation of high heat storage montmorillonite with phase change material containing exfoliated graphite nanoplatelets

ABSTRACT. In this experiment, we used a vacuum impregnation method to prepare shape stabilized PCM that contained sodium montmorillonite (Na-MMT) and Exfoliated graphite nanoplatelets (xGnP), to improve the thermal conductivity of PCMs, and prevent leakage of the liquid state of PCMs. Na-MMT has low cost and natural abundance, high adsorption and absorption capacities, and fire retardant heating rate. In the used materials, xGnP, usually produced from graphite intercalated compounds, are particles consisting of several layers of graphene sheets. As a result, we found that the FTIR adsorption spectra of paraffinic PCMs did not change, and there was no chemical interaction between paraffinic PCMs and xGnP/Na-MMT mixture. From the DSC analysis, xGnP made an impact on the thermal properties of the paraffinic PCMs/Na-MMT composites. The oxidation rate of paraffinic PCMs based composite with xGnP was greater than that of the composite without xGnP. FTIR, DSC, TGA and TCi were used to determine the characteristics of the paraffinic PCMs/Na-MMT composites.

11:30
STORAGE WATER HEATERS DESIGN OPTIMIZATION IN APARTMENT BUILDINGS

ABSTRACT. The paper is focused on the optimization and developing of design methodologies of storage water heaters for apartment buildings determined by experimental measurements in the different apartment buildings in Slovakia. The hourly maximum consumption of hot water in different apartment houses, the average hourly maximum of domestic hot water needs determined for one person and energy balance of the domestic hot water system were found out by experimental measurements. Design methodology is composed of two steps. The first step is volume design of storage water heater and the second step is its power requirement design. This design methodology seems to be more accurate than the methodology of domestic hot water storage design in the Slovak Technical Standard currently in force. The proposed methodology better reflects the current demands of domestic hot water preparation in apartment buildings in Slovakia.

11:40
PCM thermal storage system for cooling and heating of buildings
SPEAKER: Uroš Stritih

ABSTRACT. In order to reduce building energy use, system with phase change material (PCM) was constructed. During summer nights, cold is stored (PCM solidifies) and is delivered during the day for pre cooling of the fresh air, whereas in winter, heat from solar air collector is stored (PCM melts) during sunny day for heating during cold evening and night hours.

System consists of a stand-alone unit, composed of 30 plates filled with paraffin RT22HC, fan, hatch and solar air collector during winter time. The objective was to examine the functioning of the system in the office room on an annual basis. Measurements were conducted year round in order to determine system feasibility for both cooling and heating. In summer months system managed to cool down the outdoor air for about 4 degrees, but with low efficiency because of high consumption of electricity of the fan. In winter months system improves the efficiency of solar air collector, because of stored heat in PCM storage or helps to heat the fresh air for the ventilation of the room.

11:50
Possibility of Thermal Storage Systems Usage During Buildings Renovation in Saint-Petersburg
SPEAKER: Bykova Iuliia

ABSTRACT. To increase energy efficiency of building it is to apply thermal storage systems. There are multiple successful examples of their use in countries of North Europe. The article reviewed method of thermal storage system installation in a building of SPbSTU campus for the purpose of heat supply renovation program. There was solved the problem of comparing different types of heat accumulators and selection of the most suitable system for climate conditions of St.-Petersburg, which would meet the set requirements of the task. A cafeteria for 50 seats working since 12 a.m. till 4 p.m. was considered as a benchmark data. For hot water flow calculation we had to calculate the number of conditional dishes consumed in cafeteria per hour and per day. Several variants of heat accumulating were calculated: Accumulator with single-phased accumulating material (SPAM): - SPAM is water; - SPAM is granite; - SPAM is brick; - SPAM is concrete. The result shows that performance of using water as the heat storage material is better than that of others. Applying of accumulator with single-phased accumulating material is unpractical for full and autonomous supply of cafeteria. Calculation of phase-changing heat accumulator is needed, if this is not the case recalculation of heat unit with higher nominal capacity is needed.

10:30-12:00 Session SS 21: Ventilation & Air Distribution
Location: Musiksalen
10:30
Air distribution and indoor climate in a multipurpose arena
SPEAKER: Sami Lestinen

ABSTRACT. INTRODUCTION This study investigated a multipurpose arena located in Malmö, Sweden with a seating capacity of up to 13 000 individuals and in which a combination of displacement and mixing ventilation was applied. The dimensions of the arena were 100 m (L) x 90 m (W) x 30 m (H) and the interior was comprised of ice rink, seating area, cabinet region and building envelope with structures. The background of this study was that air distribution in large enclosures is not well-understood. Consequently, the objective was to investigate thermal conditions, indoor air quality, thermal comfort, airflow patterns and ventilation performance. The measured operating conditions were ice hockey game, training session and maintenance situation.

METHODS The research methods were CFD-modelling and experimental methods. The measurements were conducted with air velocity, temperature and humidity sensors and by taking thermal images. The air distribution was visualized with smoke. The sensors were installed onto 3 m high measuring masts and the variables were measured over 3 min periods. CFD models were used to investigate the flow field in the whole arena. The CFD geometry was created based on architectural plans and a building information model. Both micro and macro models were applied to describe the arena indoor climate and the box method was used to describe the air terminal units. The RANS simulations were conducted with ANSYS CFX software.

RESULTS The primary air movement was case-dependent. The primary air flowed mainly upwards along the lower-seating area and downwards along the upper-seating area. These flows confronted above the cabinet level and progressed towards the middle region. During the game, the temperature rise was only 2ºC when the displacement ventilation was introduced, and the temperature stratification was small. The relative humidity was 30-45% and the carbon dioxide content had grown by up to 300 ppm increasing the total to nearly 900 ppm. The temperature was 13-17ºC at the lower-seating area and 15-17ºC at the upper-seating area. The corresponding air velocities were below 0.25 m/s and below 0.3 m/s, respectively.

DISCUSSION The supply air temperature, variable air flow rates and the retractable stands had a notable effect on the large scale movement. The primary air movement can grow up from the combination of convection flows, heat sources and cold surfaces. It seems that principal air movement can be controlled by adjusting the air flow rates and the supply air temperature to optimize the indoor climate. The air distribution might be improved by implementing individual ventilation strategies and distributing supply air from below the seats at the whole seating area. This issue might be worth studying in the future.

CONCLUSIONS Overall, the primary air movement was case-dependent. The supply air temperature, variable supply air flow rates and the retractable stands had a remarkable effect on the large scale air movement. The temperature was 13-17ºC at the lower-seating area and 15-17ºC at the upper-seating area during the game. The corresponding air velocities were below 0.25 m/s and 0.3 m/s, respectively.

10:40
Post Occupancy Evaluation of 23 Newly Renovated Apartments in Copenhagen - Performance of Ventilation Systems
SPEAKER: Ahsan Iqbal

ABSTRACT. The present article is based on a yearlong post occupancy evaluation of indoor air quality of recently renovated 23 apartments in Copenhagen. The apartments are equipped with novel mechanical ventilation systems. The apartments can be categorised in four, according to the design of ventilation systems. All the ventilation units are equipped with parallel plate cross flow heat exchangers. The analysis in present article is based on the measured indoor quality parameters as well as energy consumptions. Among four different types of ventilation systems, Type 1 is a traditional decentralized ventilation system which works only on two speeds i.e. high airflow rates when kitchen exhaust is on otherwise nominal airflow rates. Type 2 ventilation systems are the decentralized ventilation system with motion sensors in hallways, humidity sensors in rooms and kitchen exhaust hood sensors. Type 3 ventilation system is a centralized ventilation system with the motion sensors in hallways and toilets, humidity sensors in each room, and kitchen exhaust hood sensors. Type 4 ventilation system is a centralized ventilation system with only kitchen exhaust hood sensor. Type 2, Type 3 and Type 4 ventilation systems are also equipped with a newly designed drop type dampers that has a very low pressure drop. The dominant part of the study was based on the comparison of the performance of Type 1 ventilation system with the remaining three.

10:50
Indoor Air Quality in a Zero Emission Building

ABSTRACT. The objective of this paper is to evaluate the indoor air quality in a renovated zero emission office building. Zero emission buildings should replace fossil fuels with renewable clean energy so that the saved emissions equals the emissions caused by the building’s construction, operation and materials. The building energy use has to be minimized, and for ventilation, the airflow rates should be just large enough to maintain good and healthy indoor air quality.

The studied building is Powerhouse Kjørbo, the first Norwegian zero emission office building. It has a high efficiency heat recovery wheel, demand-controlled (CO2 concentration and/or indoor temperature) displacement ventilation, and low velocities in ducts. Inlet diffusers supply slightly below room temperature air from the central part of the floor towards the facades in the open landscapes, where the workstations are located. The stairway is used as an extraction duct. In this paper, the air distribution in the open office area is studied.

The methods applied in this study are a literature survey on displacement ventilation in large enclosures, measurements involving tracer gas to analyze ventilation effectiveness and smoke to detect shortcuts on the ventilation, and parts of a survey conducted among the occupants.

Tracer gas measurements indicate stagnant zones in some parts of the office landscape, especially corners where bookshelves obstruct the flow. Further, there might be a short circuit between some of the air inlets and the exhaust. Possible alternatives for improving the ventilation effectiveness will be discussed.

The conclusion of the paper is that the occupants are generally satisfied with the indoor air quality, but if the ventilation effectiveness had been improved less air could have been used to maintain the air quality.

11:00
Development of a ventilation control system for a commercial kitchen
SPEAKER: Eri Nagashima

ABSTRACT. INTRODUCTION: In the commercial kitchen, a large amount of heat and water vapor generated by the heated cooking appliance, deterioration of the kitchen environment has become a problem. Furthermore, it requires a large amount of ventilation for thermal comfort, the increase in energy consumption by fan and air-conditioning has become a problem. Therefore, ventilation control system for varying the exhaust fan in response to the operating conditions of the cooking appliance as a method of saving energy has drawn attention, but the quantitative effects in detail has not been understood.

METHODS: The purpose of this study is to verify the energy-saving effect and thermal comfort of ventilation control system on the kitchen. In addition, it is to collect basic data for system optimization. First, we carried out measurement to introduce a ventilation control system in the commercial kitchen which is susceptible to the influence of outside air temperature last summer. Secondly, in order to verify the effect of the air flow generated from the air conditioner, we reproduced the measurement by computational fluid dynamics (CFD) simulation in relation to ventilation effectiveness and contribution to thermal environment.

RESULTS and DISCUSSION: As a result of the measurement, 56 percent of the energy-saving effect in fan consumption was reduced by introducing ventilation control system. For thermal comfort, the significant influence was not seen during “the control day” and “the no-control day”. The results of this study using a CFD simulation about the thermal environment contribution rate of the room showed that the proportion of the temperature rise of the outside air was low at “the control day”.

CONCLUSIONS: By the introduction of the ventilation control system, the energy-saving effect became higher, and the influence on thermal comfort was not significant. For this reason, the ventilation control system in the commercial kitchen is effective.

11:10
Smoke Spread In Underground Subway Station
SPEAKER: Mahmoud Amer

ABSTRACT. In the event of subway train fire smoke is the most fatal factor because smoke spreads in direction coincide with passenger’s evacuation path. It reduces visibility and can cause fatalities by asphyxiation. This research presents a numerical study to investigate the effect of exhausting smoke by single point extraction and exhausting smoke by multi-point extraction on passengers’ life safety. Also, effect of adding smoke barriers at stairs entrance on passengers’ life safety is studied. Fire Dynamics Simulator (FDS) software version 5.5.3 is utilized to simulate 6 case studies in 150 m long, 20 m wide and 13 m height domain with a subway car fire source simulated as a fire with unsteady heat release rate of 35 MW resulted from burning Heptane as a fuel. Results show that exhausting smoke by multipoint extraction system in underground subway station gives better performance than single point extraction system. By increasing the distance between vents in multipoint extraction system, tenable conditions improves at human level. Smoke barrier addition to ventilation system has a great effect on the efficiency of smoke extraction and improving tenable conditions at human level.

11:20
THE PERFORMANCE OF VENTILATION IN ESTONIAN RETROFITTED APARTMENT BUILDINGS
SPEAKER: Alo Mikola

ABSTRACT. The paper discusses the issues of energy efficiency and indoor climate after retrofitting ventilation systems in apartment buildings. The performance of ventilation was studied in field measurements of different type of Estonian apartment buildings. Indoor air CO2 levels and airflow were measured in 20 renovated apartment buildings. Airflow and CO2 levels were analyzed in the case of natural ventilation, room based air handling units, mechanical exhaust system and mechanical supply-exhaust ventilation. In the case of mechanical exhaust ventilation system, the building was equipped with an exhaust air heat pump for exhaust air heat recovery. The underlying factors of problems like the quality of maintenance, the reduction of the exhaust air flows in the case of low supply air temperatures, mistakes in designing and low building quality, have also been analyzed.

11:30
The impact of thermal radiation on condensation on cold surfaces of ventilated rooms

ABSTRACT. The appropriate design of buildings services can be fulfilled only by taken into account the following criteria: user’s comfort, indoor air quality, and energy efficiency. It is worthwhile to mention that the air moisture content is an important factor of all those aspects. Despite the humidity significance briefly mentioned above, the studies dealing with humidity aspects within buildings are generally lacking, although their number was constantly increasing during the last years. In addition, thermal radiation influence on indoor air flow has been rarely addressed. As a result, the aim of this study is to thoroughly investigate the impact of radiative heat transfer on the global exchange of thermal energy between indoor surfaces and air, and thereby to also assess the influence of this phenomenon on water vapor condensation on cold surfaces. The approach is based on CFD (Computational Fluid Dynamics) technique, using an integrated moisture – heat (including thermal radiation) – air flow methodology, required for comprehensive thermal investigations and condensation mechanisms. In essence, an equation expressing the conservation of the water vapor mass fraction is added to the basic equations governing a turbulent confined non-isothermal airflow. This allows modeling of transport and diffusion phenomena for water vapor. Regarding the condensation model, this is developed using the methodology proposed by International Energy Agency: the condensed vapor density flux is computed based on the assumption that the water vapor transport in air is mainly due to convective mechanisms, the exception being nearby the surfaces where the diffusion has the main role. In addition, the water vapor diffusion can be correlated with the convective heat transfer coefficient for applications in the field of thermal building. The value of the convective heat transfer coefficient is computed based on heat exchanges calculation between the fluid and the walls in the CFD simulations. It is worthwhile to mention that this methodology have been implemented within the CFD model by means of programming. Regarding the thermal radiation, the discrete ordinates (conservative version) method has been used. This approach solves the radiative transfer equation for a finite number of discrete solid angles. The numerical model is applied in the case of a small room equipped with a mixing ventilation system and radiant floor heating system. One of the vertical walls of the enclosure is assumed to be cold to favor the formation of condensation on its surface. For the purpose of this study, this configuration has been investigated with and without considering the radiation model. Furthermore, in order to deeply assess the impact of the radiative heat transfer in the room, several simulations have been performed with different angular discretizations for the radiation model. The results are focusing on comparing the amount of condensate and its distribution on the cold wall with and without considering the radiative part of heat transfer in the room. It can be concluded that it is not safe to disregard the radiative part of heat transfer in indoor air simulations when condensation risk investigations are required.

11:33
INFLUENCE OF SUPPLY AIR CEILING DIFFUSERS ON SURFACE TEMPERATURE OF DISPLAY CABINET DOORS AND ON CUSTOMERS COMFORT IN FOOD STORES

ABSTRACT. INTRODUCTION Vertical display cabinets are widespread in food stores, because they have a large display area and an ease access for customers. Recently, open cabinets has been replaced with closed ones in order to reduce energy consumptions for refrigeration. However, the presence of the glass doors can have an effect on product visibility because of mist formation on the glass, particularly for low temperature display cabinets. This effect appears when the temperature at the external surface of the glass falls below the ambient dew temperature, which is a quite common situation in humid climate in the mid-season, when neither indoor air heating nor cooling is performed. Today the mist formation is prevented increasing the surface temperature at external side of the glass doors by means of electrical resistances embedded in the doors frame. The glass door surface temperature can be raised enhancing the heat transfer coefficient driving the supply air towards the display cabinet doors. This paper investigates the behaviour of different air ceiling diffusers in order to reduce the risk of mist formation and the energy consumption of electrical resistances. The air flow field in the display zone, the temperature distribution on the glass surfaces and the influence of different diffusers on customers comfort condition are investigated. METHODS In order to identify the more suitable air distribution system for avoiding the mist formation on glass doors, numerical simulations have been carried out. Initially, 3D numerical simulations of isothermal airflow field has been performed and, later, summer and winter conditions were considered. The paper analyzes the effects of four way diffusers, vortex diffusers and linear diffusers. The simulation domain refers to a typical display aisle in a supermarket and symmetry conditions are exploited. RESULTS AND DISCUSSION Four-ways diffusers supply air tangent to the ceiling and cannot contribute to heat directly the front surface of the display cabinet doors. Therefore, it has been considered a vortex circular diffuser for ceiling installation with a variable geometry. The mechanism integrated into the hub allows to adjust the deflectors angle: the direction of the throw may vary continuously from horizontal with high Coanda effect up to completely vertical. For the first set of simulations, an angle equal to 45° has been considered, so that the air jet reaches cabinet doors, but this kind of diffuser produces a non uniform temperature distribution on the glass. The linear air diffuser, installed on the whole length of cabinets array, performs better reducing the energy requirements of the electrical resistances. CONCLUSIONS The temperature distribution on the surface of the cabinet doors is strictly affected by air distribution and therefore by air ceiling diffusers. The risk of mist formation can be reduced by choosing suitable air diffusers and by driving supplied air on the proximity of glass surfaces.

11:36
Priority School Building Programme: An investigation into predicted occupant comfort during the heating season in naturally ventilated classrooms

ABSTRACT. A combination of dynamic thermal and computation fluid dynamics (CFD) modelling has been used to investigate the internal conditions of a naturally ventilated classroom, designed to meet the requirements of the Priority Schools Building Programme (PSBP) Output Specification, during the heating season. The modelled designs considered natural ventilation air flow through high level top-hung-out and bottom-hung-in windows. Tested scenarios under wind and buoyancy driven ventilation, included classrooms with single sided ventilation as well as classrooms with cross ventilation into a high stack, for example a central atrium. Comfort evaluation with regards to air temperature and indoor air quality were achieved using natural ventilation as evaluated using dynamic thermal simulation models and assessed based on the requirements of the PSBP output specification. However, the CFD simulation results predicted occupant discomfort due to draughts in the regions closest to the opening windows. The air velocity and airflow patterns in the classrooms were influenced by the shape, size and location of internal openings, as well as the flowrate through the openings. Possible solutions to reduce the high air velocities experienced in certain zones include introducing more openings, with a lower airflow rate through each opening. As the results also highlighted a region closest to the window openings where the greatest discomfort is likely to occur, making this zone occupant free may also be a viable solution.

11:39
Study on performance evaluation of the natural ventilation system with phase change materials
SPEAKER: Nga Thi Hoang

ABSTRACT. Performance of natural ventilation using stack effect of staircase of building in which thermal storage medium is installed was investigated. Phase change material is used as thermal storage medium. Study was conducted by field measurement and simulation. First of all simulation model is verified by comparison between field measurement and calculation result. Then parametric analysis on performance of natural ventilation was conducted by simulation. Parameters investigated are intensity of absorption factor of solar radiation and volume of PCM and outside wind speed. The results showed that the inclusion of PCM to a solar chimney would reduce the airflow during charging period but increase it during discharging period, in comparison with the solar chimney without PCM. To evaluate the effect of PCM on performance of natural ventilation, especially in the night time, three different operation modes were developed. Each mode includes the cases of solar chimney with PCM and without PCM. Mode 1) During the day time (from 9:00 to 18:00), the rooms are ventilated forcibly by adopting a constant quantity of fresh air, and during the night time (from 18:00 to 22:00) natural ventilation is performed. Mode 2) Natural ventilation is carried out from 9:00 to 22:00. In this mode, two patterns of the day time natural ventilation were conducted. First is the case that heat is charged to and discharged from PCM during daytime natural ventilation and second is the case that only charging heat to PCM is performed. In the second pattern, there are two passages of ventilated air flow at the top of stair case. PCM is installed in one passage. From 9:00 to 18:00, the ventilated air flow through the passage without PCM in order to maximize the use of solar energy during charging period. From 18:00 to 22:00 the ventilated air flow through the passage with PCM and the heat charged in PCM during day time can be used to enhance natural ventilation. Mode 3) The rooms are air conditioned from 9:00 to 18:00, during this period all of the openings are closed, thereby the air temperature of staircase can rise higher, consequently natural ventilation effectiveness can be increased. Natural ventilation is carried out from 18:00 to 22:00. In all modes, air flow through staircase only during natural ventilation time.

11:42
Comparison of Primary Energy Consumption of DHC and VRF Systems Based on Realistic Heat Loads
SPEAKER: Goo Tsusaka

ABSTRACT. Energy conservation in buildings is a pressing issue, and there is a need for air-conditioning systems capable of operating with pronounced energy conservation effects in heat source systems. District heating and cooling (DHC) systems are a focal point as one of the key systems for energy conservation in Japan. DHC, which is used to produce intense heat sources in plants, has many advantages in terms of energy. On the other hand, heat loss from conduits and through heat transportation has been cited as a one of its shortcomings. In recent years, buildings have increasingly adopted variable refrigerant flow (VRF) systems. These are convenient for users and their individual control performance is acceptable. These systems are also responsible for attaining better energy conservation at rated capacities in individual equipment. However, there are no times when the rated capacity is reached during actual air conditioning, pointing out the reality of operating at low loads. Hence, the efficiency in VRF systems at low-load operation is lowered significantly. Over the past few years, several studies have been made on comparison of the energy conservation effects of DHC and VRF systems by measurement data analysis. However, measurement data analysis alone could not compare both systems under the same conditions and not evaluate those quantitatively. This report aims to compare primary energy consumption by measurement data analysis and simulation of the heat load generated over one year in a real office, considering the case of obtaining heat supply from a DHC plant and the case of operating a VRF system. Building floors are selected as research subjects in buildings obtaining their heat supply from a DHC plant. The analysis of heat loads measures the operating status of air conditioners over one year. In the case of VRF system, selecting equipment in the floors and simulate the energy consumption of a VRF system by using the heat load factors calculated from the results of a field survey. The water transport factor (WTF) and air transport factor (ATF) are calculated by using measurement dates and are added to the primary energy consumption. Results confirm that, throughout the year, a better energy efficiency trend is obtained using air conditioners and variable air volume (VAV) systems by taking the heat supplied from a DHC plant in the region rather than using air conditioning in VRF systems. On the other hand, it is confirmed that the energy efficiency of the systems can be reversed depending on the quantity of heat loads or the equipment capacity. There is a need to improve both DHC and VRF systems. In the future, quantitative evaluation of the redundancy of capacity is necessary, this is suggested as a technical problem to be solved in the future in order to develop high- efficiency VRF systems with an emphasis on partial load characteristics and to make air conditioning systems of the secondary energy side, including DHC systems, highly efficient.

11:45
Demand-driven HVAC control in large-scale rooms based on occupancy distribution measurement with indoor positioning system
SPEAKER: Wang Wei

ABSTRACT. Commercial buildings consume substantial amount of energy and require more sophisticated control strategies to fulfill occupants’ comfort needs, especially, in the large-scale spaces, where various occupancy patterns result in uneven load distribution. Therefore, higher resolution of occupancy information is the premise of better system operation. The development of indoor positioning system in recent years enables the possibility of more scientific and precise control of building HVAC system based on occupants’ geospatial distribution. This paper proposes a supervisory demand-driven control systems based on indoor positioning system for the operation of air conditioners in large spaces. The proposed system focus on optimizing the ventilation rate based on the number of occupants and their locations in a space, which covered by Wi-Fi network and BLE network. In this study, the experiment space is divided into small thermal zones, which are served by independent variable air volume boxes. The temperature distribution and energy consumption in the space is simulated with computational fluid dynamics (CFD) models. The relation between cooling load variation and occupancy pattern is studied to examine the energy saving potential of different control mechanisms. When the HVAC systems in office focus on the occupants based on proposed methodology, energy-saving can be achieved and thermal comfort of occupants can be guaranteed at the same time.

11:48
Energy Efficient Ventilation for Pig Farms

ABSTRACT. One of the main tasks of intensive pig farming is to comply with animal husbandry technology, providing the necessary conditions for the keeping of animals. There fore, one of the most important objectives is to provide effective ventilation. The ventilation system should insure indoor air parameters in compliance with specific requirements for pig keepings. Indoor microclimate is one of main factors which have impact on quantitative and qualitative indicators of pig farm’s productivity. Microclimate in pig farms is controlled by the ventilation and heating systems which provide optimal indoor parameters, temperature, humidity, air velocity, CO2 concentrations, during the whole year. For efficient operation of ventilation and heating systems the properties of external building envelopes such as thermal mass and heat transfer coefficient should be taken into account. The aim of this paper: to determine the energy balance for heating season with different ventilation system devices and air treatment schemes. Optimization of the operation schemes of the ventilation devices and their consumption of energy is an important measure from the viewpoints of the animal welfare, the cost reduction, and the environment conservation. Methodology has been elaborated the calculation of energy consumption for various sets of ventilation systems in the air treatment processes using systems optimization. The operation of various air treatment devices is analyzed by the variations in the enthalpy of the outdoor air, the supply air and the exhaust air treatment processes. Using the climatologically data of Latvia about the repetition frequency of the combinations of the outdoor air parameters and recalculating them to the enthalpy of the outdoor air parameters.

11:51
Indoor Air Quality of schools a problem, but what about Day Care Centres
SPEAKER: Wim Zeiler

ABSTRACT. Aims The indoor quality of an occupied space is very important for the well-being of its occupants, especially in the case of young children. The poor condition of the indoor environment in almost 80% of the Dutch classrooms has led to the drafting of a program of demands for fresh schools. Following this program of demands should improve the cognitive performance of the pupils. This program of demands is currently only available for the accommodation of primary schools whilst a healthy indoor environment for younger children (age 0-4) is far more important. The lungs of a young child are still growing and adverse conditions could affect this development. Also little children spend a lot of their time in daycare centers while parents are at work, while little is known about the effects of different indoor environmental factors present in these day care centers and the quality of the buildings in which these day care centres are accommodated. Therefore this research investigated the quality of the accommodation of a Dutch daycare center.

Investigate approach Besides an extensive literature research actual measurements were performed in three day care centre. Some experiments were performed to find out the importance of the configuration and types of baby cots.

Main conclusions This research investigated the quality of the accommodation of a Dutch day care centre which led to a tool describing the quality needs (e.g. quality standard) for the accommodation of day care centres. The results of our detailed studies were compared with the results of earlier Dutch more global studies in day care centres, in which more than 60 centres were investigated. Also the results are compared with the outcomes of research on school ventilation. The results proved that the situation in day care centres is even worse than that of schools within the Netherlands. More attention is needed to improve the current situation.

11:54
Prediction of Cross-Ventilation Performance of Detached House Using Wind Catcher In Residential Buildings
SPEAKER: Hirano Aoi

ABSTRACT. INTRODUCTION Utilization of cross-ventilation is important to improve comfort of the housing, but it is usually difficult to obtain a sufficient cross-ventilation in normal openings in residential buildings. Previous studies showed that installation of wind catcher was effective method as improving cross-ventilation performance. But it is not sufficiently consider discharge coefficient of openings and prediction accuracy of ventilation flow rates when installing wind catcher. So the purpose of this study is to improve prediction accuracy of ventilation flow rates prediction. And this study considered discharge coefficient of openings, the applicability of local similarity model, and indoor air when installing wind catcher.

METHOD First, in wind tunnel experiment, we compared discharge coefficient of normal openings as it of openings installed wind catcher. And, in CFD analysis, by using a chamber model, we considered airflow characteristic of normal openings and openings installed wind catcher. Second, in CFD analysis, we considered prediction accuracy of ventilation flow rates of openings installed wind catcher in three ways. Three ways are to analysis across, to apply dynamic similarity model, and to define discharge coefficient to 0.67. Third, we considered the difference of indoor airflow by the position and the number of openings installed wind catcher.

RESULTS In many cases, discharge coefficient of openings installed wind catcher was smaller than 0.67 that discharge coefficient of normal openings. And it roughly match relationship between discharge coefficient and chamber pressure when compared in case not installed and installed wind catcher. Next, ventilation flow rates calculated by defining discharge coefficient to 0.67 greatly exceeded ventilation flow rates calculated across. And ventilation flow rates calculated in using the local similarity model roughly match ventilation flow rates calculated across. In addiction, indoor airflow was changed by the position and the number of openings installed wind catcher. And ventilation flow rates increased by installing the face, shifting the position slightly.

CONCLUSION Discharge coefficient of openings installed wind catcher is smaller than it of normal openings. It is possible to improve greatly prediction accuracy of ventilation flow rates of openings installed wind catcher by using the local similarity model. And it is possible to change indoor air freely by the position and the number of openings installed wind catcher. So it is possible to improve comfort of the housing by successfully installing wind catcher in openings.

11:57
Long-term measurement on the actual condition of airborne microbe concentration in office buildings.
SPEAKER: Koji Shima

ABSTRACT. Since high-rise building of a building progressed and sufficient control of maintenance was not performed in indoor environment by high economic growth of Japan in the 1960s, the issue of health disturbance arose. In order to improve the situation, The “Law for Environmental Health in Buildings (Healthy building law)” was enacted in 1970. By the Healthy Building Law, it aims at making it improved and increased on the environmental hygiene of a building by carrying out control of maintenance in accordance to "building environmental hygiene standard." By this law, the thing of the building which satisfies the conditions is defined as "the specific building." Furthermore, it is to set up the standard of suspended particle concentration, carbon dioxide concentration, carbon monoxide concentration, temperature, relative humidity, and air velocity, and to measure once every less than two months. After the Healthy Building Law was enacted, the improvement of indoor environment was achieved, but it shows the tendency whose building which does not satisfy an environmental standard value increases in recent years. As the cause, revision of Energy Saving Law in 2010, revision of the Healthy Building Law in 2002, the influence of the East Japan Great Earthquake in 2011 can take into consideration. This study was conducted as part of Japanese welfare labor science research in the 2015 fiscal year, and it aims at grasping the actual condition of office building environment. The item of air temperature, relative humidity, airborne bacteria, airborne fungus, and the suspended particle was measured in office buildings in Tokyo and Osaka, and continuation measurement for one year was performed on the item of temperature, relative humidity, and carbon dioxide concentration. The measurements were performed in six office buildings in summer and ten office buildings in autumn. The results show that in one office building, concentration of airborne bacteria and airborne fungi exceeds the maintenance reference standard of Architectural Institute of Japan. Supply air concentration showed 90% of the value of the outside air concentration in one office building of summer. About fungi concentration, 11 offices among 14 offices in Osaka exceeded the maintenance standard of Architectural Institute of Japan. From the above results, airborne bacteria concentrations and airborne fungi concentrations almost satisfied the maintenance standards in summer. In case of introduction of fresh air by individual air conditioning system, without passing through an air filter, 90% of outdoor pollutants were introduced into indoor environment. The findings show that it is desirable to introduce an air filter in a ventilation system. 80% office buildings in Osaka were not satisfied with the maintenance reference standard of the Architectural Institute of Japan.

12:00
A Study on the microbiome in Hospital Waiting room
SPEAKER: Yuina Fujii

ABSTRACT. Recently, SARS (Severe Acute Respiratory Syndrome), MERS (Middle East respiratory syndrome coronavirus, MERS-CoV), avian influenza, and tuberculosis become the issue worldwide. Therefore the countermeasures against aerial and droplet infection caused by bacteria and virus indoors are required. In this study, which is a part of the studies on microbiome in hospitals, results obtained by the measurements conducted in a Japanese hospital were reported. In order that a weak person may use a hospital, the environment in a hospital has big influence on a weak person's health. Besides, the outpatient waiting room used by unspecified people needs the upkeep way which responds to various environments. The visitor waiting room is the place where nosocomial infection risk is high. Recently, nosocomial infection accident such as influenza, serratia, Legionnaire's disease, etc. occurs in indoor environment, so the things for environmental countermeasures for a hospital become important. Moreover, in recent years, the so-called opportunistic infection due to immunity lowering of patients in hospital environment becomes a problem. This study aims at grasping the characteristics of infection diffusion of the pathogenic organ in a hospital by performing the so-called Metagenome analysis which analyzes DNA directly collected from the environmental sample, without passing through the process of cultivation. In this study, air sampling of carbon dioxide concentration, suspended particles, and suspended particulate matter for DNA analyzing in visitor waiting room, respiratory system waiting room, and outdoors of a Japanese hospital was performed. As the sampling method, the PTFE Membrane filter was used and the quantity of suction was set as 180L (3 L/min *60min). About DNA, 16SrRNA gene was analyzed using the next-generation sequencer. As the results, carbon dioxide concentrations in respiratory system waiting room were higher than visitor waiting room. Moreover, about the suspended particulate, the visitor waiting room showed the high value. However, the difference of the concentration became small as particle diameter became large. About the result of DNA analysis, microbiome in outdoor air was also detected in the visitor waiting room. Moreover, about microbiome, it shows the difference between visitor waiting room and respiratory system waiting room.

10:30-12:00 Session SS 33: Indoor Environment
Location: Europahallen
10:30
A Framework to Assess Exergetic Efficiency for Thermal Comfort
SPEAKER: Hongshan Guo

ABSTRACT. Exergy analysis is usually used to supplement traditional thermodynamic efficiency based on only energy balances in evaluating overall system performance. It examines the connections between different components, and is therefore helpful in preventing efficiency losses due to inadequate system integration, which formed the foundation of low exergy (LowEx) building design: using lower exergy for space heating/cooling allows for larger efficiency as well as overall economic benefits. A few recent studies have been able to link human comfort with the low exergy concept, arguing that the lowest human exergy destruction rate warrants thermal comfort. The current studies available and the complexity of the models they proposed warrants a review. We therefore examine three such human exergy exchange models in this paper. Models from Shukuya, Wu and Mady were compared against one another for synergies and discrepancies. A conceptual framework was then proposed to include the exergy consumption of human body as the final link in exergy supply chains for LowEx systems. This framework would then be validated conceptually for its usages in existing LowEx building systems. It was concluded that the proposed framework could work for some types of systems, but may require additional development to serve as an alternate for LowEx building systems across the board.

10:40
THE HYGROTHERMAL SURVEY IN RECONSTRUCTED OFFICE BUILDING WITH CHILLED BEAMS SYSTEMS

ABSTRACT. INTRODUCTION Along with a need for more energy efficient buildings (reduced infiltration of ambient air), a combination of pollutants generated indoors and inappropriate ventilation have resulted in issues associated with indoor air quality. Complaints and problems occur in many cases of unacceptable temperature or inadequate function of ventilation and air-conditioning system. The study introduced field measurements of hygrothermal microclimate in a reconstructed office building in the Czech Republic.

METHODS Experiments were carried out in a building with open-plan offices in summer and winter period. The building was renovated in 2005. Changes has been made in mechanical ventilation and cooling systems as well. To reduce the thermal load (mainly in summer time and from office equipment) the chilled beams have been installed. The work includes objective and subjective measurements of this space with occupants. Subjective method was provided by questionnaires filled by workers. Within objective measurements was measured several values, included a non-uniform constituent in space. Measurements were carried out at the 3th floor, where complaints of occupants had been reported. There are around 200 workers on this floor who make PC work.

RESULTS Primarily results of the subjective measurements of occupant´s group have shown problems with thermal comfort of the occupants. Even though, in the case of summer period, the results show that the occupants felt cold indoors. Moreover, occupants have had comments in the field of their thermal comfort, as: a) bothered by cold air on the body parts – neck, shoulders, hands, sometimes ankles, b) bothered by cold air “falls” from ceiling (from ventilation system), c) worse situation at mornings with temperature – during day it become more stabilised.

DISCUSSION In spite of complains from occupants, it can be stated, that cooling system reacts well. Cooling system switches on when 24 °C is reached. However, the chilled beams regulation of each section, it seems to be unfavourable. One of the eight regulation section supplies cooling and fresh air for approx. 40 people. This is controlled by sensors which can be influenced by bad installation in space, covering by furniture, etc. Between those sections there are significant differences. But surely, the role plays several factors, e.g. annoying airflow, also often mentioned by occupants.

CONCLUSIONS The microclimate hygrothermal survey in reconstructed building with open-plan offices was performed. The local discomfort was reported by the occupants. Results of the study shows how measurements correlated with reported discomfort by workers. One of the observed problems has been proved to be in covering by furniture of the sensors and radiators, badly designing cooling sections of chilled beams and insufficient supply of fresh air for return to the work after weekend days.

10:50
Improvement of working thermal environment for female office workers

ABSTRACT. The draught can cause air-conditioning syndromes such as oversensitivity to cold, headache and physical listlessness. Female office workers wear a lower amount of clothing in comparison to their male counterparts. In an air-conditioned office space in summer in Japan, women conduct thermoregulation by putting on cardigans etc. But this action does not greatly contribute to improving conditions for the legs and feet, which comprise lower extremity of the body. The purpose of this paper is to demonstrate the effect localized heating of the feet has on physiological and psychological reactions in an air-conditioned environment in summer, by means of the quantitative research based on the indoor thermal environment evaluation index ETF. ETF converts the effects of the following parameters into a temperature equivalent value: change of posture, air velocity, thermal radiation, contact material surface temperature, and humidity. The improvement of sensational and physiological temperature by localized warming of the body may contribute to a healthy working environment for female office workers, their safety, and a reduction in air conditioning energy expenditure. The subjective experiments were carried out in the artificial climate chamber. Thermal environment conditions were established through a combination of 3 air temperatures (24°C, 26°C, and 28°C) and 5 sole-of-the-foot/floor surface temperatures (equal to air temperature, 26°C, 28°C, 30°C, and 32°C). There were combinations of air and sole of feet heating device’s surface temperatures. Constant air velocity and relative humidity were maintained for all conditions. The experimental posture was the sitting in a chair position. The subjects were eight healthy young females. Before the experiment, the subjects stayed in a seated posture and at rest for 60 minutes or more in the pre-test artificial climate chamber having the same air and wall temperatures and relative humidity as the test artificial climate chamber. Then the subjects were swiftly moved to the test artificial climate chamber where they were placed in an exposure position and exposed to a set of thermal environment conditions for 15 minutes. The thermal environment conditions, the physiological and the psychological responses were measured. The effect of air temperature was more strongly expressed in mean skin temperature than the effect of heating by means of heat conduction. The result of heating by means of heat conduction was expressed more strongly as a psychological effect than as a whole-body physiological effect. Heating by means of heat conduction was a thermal environment factor that compensates for a low temperature in whole-body thermal sensation and whole-body thermal comfort. The effect of heating due to heat conduction was expressed in the change in sole-of-the-foot skin temperature. Applying small heat conduction demonstrated the result of improved whole-body thermal sensation and whole-body thermal comfort. Therefore, heating by means of heat conduction increases sole-of-the-foot skin temperature and can be considered to alleviate sensitivity to cold through stimulating the extremities of the body.

11:00
Integrated design approach for improving personal summer thermal comfort in existing office buildings with suspended ceilings
SPEAKER: Karsten Voss

ABSTRACT. Suspended ceilings are widespread in commercial buildings in Europe, especially in offices. Beside the advantages with respect to room acoustics and cladding of technical installations below the ceiling the major disadvantage is the reduction of the thermal capacity of the room. A lack of thermal capacity is one reason for high summer temperature peaks in the absence of cooling devices. The hot summers of 2003, 2006 (and 2015) and the predicted climate change with the anticipated temperature increase and intensive heat waves have strengthened interest in summer thermal comfort in existing office buildings. A typical measure known in Southern Europe is the application of ceiling fans. The fans offer a technically simple, inexpensive and, above all, effective method to increase air movement and thus thermal comfort in a room. The effects are described already within thermal comfort standards such as DIN EN ISO 7730-2006, DIN EN 15251-2007. On the other hand classical ceilings fans are designed to address more than one workplace thereby creating conflicts between individual preferences related to air velocity. The new concept investigated and described in the paper is based on small (Ø 300 mm), individual fans as integrated part of the suspended ceiling section directly above the workplace. The fans are designed to create a circulation air flow rate of 115 m³/h thereby increasing air movement in a radius of about 50 cm to 0.3-0.5 m/s at the upper body level of a seated person. Due to efficient DC motor technology the power to run a single fan is just 5 W. Each fan can be controlled individually with variable flow rate by an application on the work place computer. The air supply to the fan is created by modifying a large part of the suspended ceiling segments from acoustic panels to expended metal meshes but still keeping acoustic panels above the workplaces. Measuring the reverberation time of the room as well as user interviews underline the finding that the room acoustic still fits the needs of an office environment. The metal meshes increase the thermal coupling of the room air to the ceiling thereby increasing the thermal capacity of the room. The improvements for the summer thermal comfort results from increased air velocity as well as increased thermal capacity. The paper reports on measurements performed in a 4 person office environment in summer 2015 and correlated thermal simulations. Results are compared with earlier investigations related to usual ceiling fans [1].

[1] Voss, K., Voß, T., Otto, J., Schweiker, M., Rodriguez-Urbinas, E.: Investigation of ceiling fans for improving summer thermal comfort, Proceedings of 2nd Central European Symposium on Building Physics (2013) 381–385.

11:10
Energy efficient thermal comfort in temporarily occupied space – A summer case study in Tianjin
SPEAKER: Bin Yang

ABSTRACT. Temporarily occupied space is defined as an air-conditioned space in which most of occupants stay for less than a certain period (e.g., 40 minutes) such as post offices, supermarkets, bookstores and banks. After moving from a hot and humid outdoor environment to an air-conditioned temporarily occupied space in summer, thermal alliesthesia takes effect, which refers to ‘thermal pleasure sensation and overshoot generated by the restoration of thermal stress toward a neutral interior condition’. Because of the overshoot, occupants’ acceptable temperature ranges in temporarily occupied space are possibly elevated by less intensified air conditioning systems while they still feel comfortable. To address this issue, a human subjective response study was performed in one climatic chamber used to simulate temporarily occupied space in Tianjin. 16 healthy university students, 8 males and 8 females, were exposed to outdoor environment for 20 minutes before they stayed in the chamber for 40 minutes. Their votes on thermal sensation, comfort and preference were recorded for evaluation at different time points. The results show that, in summer, the optimal design temperature range for temporarily occupied space in Tianjin is elevated to 27 °C to 29 °C without influencing thermal comfort, enabling large amounts of cooling and dehumidification energy to be saved for air-conditioning systems. Meanwhile, thermal comfort for staffs who have long term exposure to the environment could be maintained by personal comfort systems such as desk fans or personalized ventilation in terms of spatial alliesthesia.

11:20
Measurements of clo value using heat flux sensors and human body

ABSTRACT. For the purpose of this study, the clo value measurement experiment using a human body and a heat flux sensor is conducted, and comparison and examination with the clo value in the thermal manikin were performed. The balance of metabolic heat production and heat loss causes our thermal sensation. We can adjust our thermal sensation by regulating heat loss from our body. Changing clothes is one of the methods of adjusting heat loss. Clothes act as a thermal insulator, which suppress heat loss outside of the body. The thermal insulation of clothing (clo value) is very important when evaluating the thermal environment of our living spaces. Therefore, it is necessary to measure a clo value for every clothing ensemble of residents. A clo value is not a peculiar value for every clothes. For example, even if it is the same clothes, clo value changes with differences in the posture of those who wear. And so, it is indispensable to measure clo value with various postures. However, compared with the variety of Japanese housing resident's posture, the clo value data measured by previous research is still few. The reason with few measurement data of the clo value is because the special, expensive device such as the thermal manikin is necessary for the measurement. An easier new clo value measuring method than before needs to be developed, without needing special and expensive equipment, such as a thermal manikin. ISO 9920 standardizes the clo value measuring method using a thermal manikin. However, thermal manikin is very expensive equipment. Moreover, thermal manikin cannot change into the posture which Japanese people often take in their home such as AGURA (sit cross-legged). A clo value measuring method using a human body is also shown in ISO 9920. Human body can be changed into any postures. According to the measurement theory shown in ISO, clo value is calculated by heat loss from a human body, average skin temperature, and air temperature. However, there are many measurement items, some of these items are difficult to measure, are required. It is desirable that the clo value in the posture can be measured without using special equipment. A clo value may be able to be more simply measured by measuring the amount of heat loss from a human body directly with a heat flux sensor. A heat flux sensor measures the heat flux that passes the sensor stuck on the measuring object part. It is widely used in various fields including mechanical engineering and electrical engineering. In order to correspond to various measuring objects, the form of the sensor of a heat flux transducer and improvement of sensitivity has been progressing. And heat flux sensor that can measure the heat flux from the surface of a complicated and soft human body is increasing too. The purpose of this research is to develop a simple new clo value measuring method, which use a human body and heat flux sensor.

11:30
Investigating the Ability of Prevailing Thermal Comfort Models to Predict Thermal Comfort in Homes

ABSTRACT. Thermal comfort in dwellings has recently received more attention due to reported discomfort problems as a consequence of low-energy requirements in the Danish building legislation. Further attention to thermal comfort in the design of low-energy dwellings is therefore needed. PO Fanger’s stationary PMV model and the adaptive model from the European SCATs project are both described in the European standard EN 15251 and are prevailing thermal comfort models in European context. However, neither of the two comfort models has been tested on whether they are appropriate models for predicting occupant comfort in dwellings in colder climates.

This paper reports on an experiment where the ability of the PMV model and the adaptive model from EN 15251 to predict thermal comfort has been tested in a dormitory building in Denmark. Simultaneous subjective votes and objective measurements have been gathered during three summer months. The subjective votes including questions about clothing level were conducted by an online comfort survey sent to the participants in text messages. Indoor air temperature and relative humidity were measured leaving mean radiant temperature, air velocity and metabolic rate unmeasured.

A total of 315 subjective votes from 20 participants were gathered with parallel objective measurement. Analysis of the results suggest that the PMV model underestimates the subjective thermal sensation in the dorm apartment. Analysis of the adaptive model suggests that it predicts thermal comfort in dwellings fairly accurate with only a minor difference in regression equation compared to the original model.

Bearing in mind that the sample size of the experiment is modest, the conclusion is that the PMV model did not reflect the actual thermal comfort in the dorm rooms, but that the methodology of the adaptive model in EN 15251 could be applicable. Overall, the result of the investigation suggests that relations between the thermal comfort votes and objective measurements are in general very vague. This could be because thermal comfort in dwellings is an individual matter. It is noted that due to the sample size of this experiment, it cannot be dismissed that PMV is able to predict thermal comfort in dwellings or that the adaptive model is applicable. Future research in this area would be to expand the sample size significantly.

11:33
Study on Housing Indoor Thermal Comfort Evaluation Using Measurement Around the Winter
SPEAKER: Mi-Yeon Kim

ABSTRACT. In this study, amenity evaluation technique for indoor air quality in the underground space was developed and evaluated real-time amenity by utilizing real-time sensor monitoring system equipped with the technique. The factors used for amenity evaluation were PMV value. The purpose of this paper is to provide a thermal comfort index to Zero Energy Residential Building. For making a thermal performance index of the Zero Energy ,Residential Building was a questionnaire and monitoring to the occupant of existing residential building. Questionnaire results showed that the amount of clothing a woman is higher than men, this amount of clothing range was 0.45 ~ 0.92 clo. Main activity in the indoor is sleeping, seating, cooking, house cleaning, it confirmed by the hourly activity. Indoor thermal performance results, the thermal comfort was high as on the canopy household > the top floor household > the lowermost story household > the middle floor household. Research results will be used by comparison and evaluation of thermal comfort data between the Zero-Energy Make Up House and exsiting residential building.

11:36
Survey of Thermal Environmental Deviation in Offices
SPEAKER: Masanari Ukai

ABSTRACT. Conventional air-conditioning systems aim to provide uniform comfortable environments by the prevention of temporal and spatial variations in the thermal environment. However, conventional convection air-conditioning systems may create discomfort with air drafts and non-uniform thermal environments. On the other hand, radiant cooling system do not create an uncomfortable air draft. Therefore, radiant systems are expected to improve thermal comfort. However, an index evaluation method for assessing the thermal comfort of radiant cooling systems has not been established yet. Evaluation using the conventional thermal comfort indices involves considering a single person in a room to be a representative of a group of people with common characteristics. In the results of a survey of thermal environment acceptability by the authors, complaints from workers sensitive to cold occurred frequently in offices with convection air-conditioning systems. In contrast, the offices with radiant cooling systems did not receive many complaints from sensitive workers. Moreover, even if the average indoor thermal environment was in a comfortable zone, workers who are sensitive to cold complained that when they sat under the air vent in the actual working space using a convection air-conditioning system, the thermal environment felt uncomfortable. Therefore, going forward, thermal environment evaluation should be carried out from the point of view of such individuals. This study is aimed at establishing a new thermal comfort index for evaluating radiation air-conditioning systems. This paper reports on the characteristics of thermal environmental distribution in three offices that have adopted a variety of air-conditioning systems. The results showed that the thermal environmental distribution was very uniform for radiant cooling systems and underfloor air-supply systems when compared to standard convection air-conditioning systems. From the above results, this paper presents the concept of introducing a new thermal comfort index for provided temperature and required temperature.

11:39
Comparison of test methods for mould growth in buildings

ABSTRACT. Introduction Between 12 and 20% of all dwellings in Denmark have mould growth that should be acknowledged and remedied. Most of these infestations are small and only of concern because they could grow into infestations with impact on occupant health. There is a need for increased awareness, willingness to act and quick and simple methods for objectively assessing whether a building structure is infested. Mould growth may be visible on inner surfaces. It may however also be invisible and occur on the back side of wall paper, below wooden floors, inside composite walls with cavities etc. Applying a surface-based method to quantify such mould growth is not simple because access to the hidden surface requires some destruction that will require efforts to renovate regardless of the findings. Some methods have tried to overcome this obstacle by sampling fungal emissions in room air. The purpose of this work is to compare a range of test methods and kits available in Denmark. A further purpose of this work is to evaluate whether air-based methods provide information qualifying decisions concerning renovation needs.

Methods After a survey identifying available methods on the Danish market for assessing mould growth in dwellings, a case study was conducted to test the usefulness of the methods in four dwellings of different typology and with or without known mould infestations. In each dwelling eight methods were used in parallel. The criteria for choosing the methods for the case study were that they had to be non-destructive, relatively quick and easy and frequently used by building professionals. The following methods were used: - Visual and olfactory inspection and occupant interviews - Culture methods (to detect specific species of moulds) – air and surface - MycoMeter (quantitatively measures activity of fungi enzymes) – air and surface - DNA testing (quantitatively measures specific species of moulds) – surface - ProClean (quantitatively measures protein levels) – surface - Mould Guard (registers humidity level of a material) – surface

Results and discussion Variation occurred both within a dwelling and within measurements taken in parallel. The two types of air samples show low levels of mould growth, even in a situation where the results of the other methods indicate high to moderate growth. The ProClean method reacts to all proteins not just moulds. In a parallel test where swabs touched human skin before use the swabs all gave positive results, even when the uncontaminated swabs did not. With culture and DNA testing there were some difference in the species that each identified.

Conclusion The chosen methods measure different aspects relating to mould growth; CFU, fungi enzymes, fungi DNA, protein levels and humidity and vary between quantity, species or both. Therefore the results were, as expected, quite varied. We found visual and olfactory inspection to be quite indicative of mould growth, while the air sampling methods seemed only to react to very comprehensive infestation with fungi at a high risk of false negatives.

11:42
Indoor/Outdoor Concentration of Particulate matter and Polycyclic Aromatic Hydrocarbons at roadside site in Agra India
SPEAKER: Jamson Masih

ABSTRACT. Introduction Air pollutants such as Particulate matter is the most ubiquitous and most complicated other than its health effects, its role is to control a number of atmospheric processes such as deposition of different compounds, the optical properties etc. The primary sources of PM2.5 outdoor include, fuel combustion processes in transportation (traffic related) and energy production, whereas cooking, smoking and cleaning activities contribute primarily to the indoor PM2.5 levels. The concentration of particles outside the house, the rate of air exchange and the depositional characteristics of the particles are governing issues to generate particles concentration within the house generation governed the particle concentration inside a house. Thus it is necessary to study the particulate pollution along with its associated PAHs concentration. The aim of the present study to measure the fine and course particulate matter and PAHs concentration in both particulate as well as gaseous phase in Indian household condition.

Results & Discussion PM1, PM2.5 and PM10 Particulate mass concentrations and twenty-three polycyclic aromatic hydrocarbons (PAHs) were measured In Indoor and outdoor environment of Agra, India known as the home to the world famous heritage monument ‘The Taj Mahal’. Sampling was done for all three seasons i.e. winter, summer and rainy during the year 2007 and 2008. Particulate mass concentrations were measured online by using Grimm aerosol spectrometer. PAHs were collected by using XAD-2 resin tubes (600 mg) for gaseous phase PAHs and PTFE filter paper (37 µm dia) for particulate PAHs. The individual PAHs were identified by using a gas chromatograph with mass spectrometry detector (GC/MS). The mean concentration of PM1 was 101.52 µg/m3, PM2.5 138.46 µg/m3 and PM10 235.17 µg/m3 in indoor, whereas at outdoor the mean concentration of PM1 was 104.01 µg/m3, PM2.5 150.23 µg/m3 and PM10 250.81 µg/m3. The total PAHs concentration of 23 PAHs was 1527.74 ng/m3 in indoor and at outdoor it was 1691.50 ng/m3. A great variation of individual PM and PAHs concentration was observed in indoor and outdoor environment pointing out different sources. In the study it was seen that the lighter molecular weight PAHs were found in gaseous phase whereas heavy molecular weight PAHs were associated with the particulate phase. Monthly and seasonal variations of coarse and fine particulate matter have been studied. Significant seasonal variations were found for particulate and PAHs concentrations which obtained using the daily and monthly average particulate concentrations. The B(a)P-equivalent exposure, calculated using Toxic equivalent factors (TEFs). The Total B(a)P equivalent exposure was 15.9 ng/m3 in indoor and at outdoor it was 16.25. To find out the possible factors accounting for PAHs Principal Component analysis and PAHs diagnostic ratio were applied. The results obtained from principal component analysis and PAHs diagnostic ratio showed that in indoor PAHs were mainly generated from smoking, cooking and oil fumes and also influenced from outside. At outdoor the sources were vehicular activity, biomass burning and also from diesel fuel operated gen sets.

11:45
A study on ozone and PM2.5 concentration levels inside and outside hotel rooms in Nanjing city, China
SPEAKER: Zhijuan Shao

ABSTRACT. People generally spend most of their time indoors. Indoor pollutants such as ozone and PM2.5 could adversely affect human health, particularly in relation to impaired lung function. For a realistic assessment of human exposure, both outdoor and indoor measurements of ozone and PM2.5 concentrations are required. The objective of this paper is to provide reference data for people who want to improve the indoor air quality (IAQ) and reduce the personal exposure to ozone and PM2.5. Using ultraviolet adsorption method and optical particle counting method, we carried out consecutive measurements on ozone and PM2.5 concentrations inside and outside a couple of hotel rooms in Nanjing city, China. In general, the ozone concentration rises in the morning, reaches the peak at noon or in the afternoon and then declines. The peak time is usually between12 pm and 4 pm. The indoor ozone and PM2.5 concentrations can be a significant fraction of those outdoors and are highly dependent on the ventilation pattern. Our measurements in a non-air-conditioned room show that the maximal indoor/outdoor ratios for ozone and PM2.5 are 50% - 80%, and 40% - 70%, respectively. While the corresponding calculated average values are approximately 0.4 and 0.6. This paper also studies the relationship between ozone and PM2.5 concentration levels under different circumstances. Furthermore, the effective methods to reduce indoor pollutant levels are discussed.

11:48
Evaluation of the indoor air quality in a library using natural CO2 as tracer gas

ABSTRACT. The indoor air quality was studied in the library of the Faculty of Civil Engineering in Bratislava, where people are considered to be the main source of pollution, expressed as the number of air changes per hour. The present results refer to the period of several weeks in December 2014, when the room occupancy was high due to the approaching end of the winter semester. The collected data show similar course of CO2 concentration every working day throughout the measurement period, when the concentration was increasing in the morning, peaking in the afternoon and slowly decaying during the night. The gradual CO2 decay during the night allowed for calculation of the air change rate using natural CO2 as the tracer gas. The air change rate over the measurement period was estimated to 0.11 ± 0.04 1/h, indicating a good air-tightness of the envelope and thus the heat loss by infiltration reasonably low. However, as the required levels of ventilation require the air change rates from 0.4 up to 2.3 1/h depending on the occupancy and the standard used, comparison with ventilation requirements as defined in various documents renders the current air change rate insufficient. Although at low occupancy levels the remedy to this problem could be opening windows, mechanical ventilation has to be probably installed to achieve sufficient indoor air quality at high occupancy.

11:51
Green Aspects of PCO Method – Reference to UV Turbo
SPEAKER: Karna Dahal

ABSTRACT. Introduction Cooking activities generate dirty exhaust air which contains grease particles and odorous compounds. Grease particles are deposited to kitchen walls, ventilation ducts, kitchen equipment and roof of the building. If fire catches to grease deposition, enormous damages may happen to building objects and human beings. Also efficient heat recovery needs relatively clean air without grease to be stuck to the recovery fins. Therefore, kitchen exhaust air needs to be filtered properly before supplying to outer atmosphere. Photocatalytic oxidation (PCO) reaction is an appropriate cleantech solution method for purifying kitchen exhaust air. It significantly removes grease particles and abolishes smell. It works with small energy, purifies exhaust air substantially with ozone free ultraviolet (UV) light and without the use of harmful chemicals in the UV Turbo system. UV Turbo system has been tested and verified both scientifically and practically. Background Information UV Turbo system is the advancement of TurboSwing system invented at Jeven Oy. The advance technique is based on photocatalytic oxidation (PCO) reaction in which ozone (O3) free UV light and titanium dioxide (TiO2) as catalyst have been used. UV/TiO2 technique was tested in laboratory and real kitchen environment to confirm grease and odor removal efficiencies. Methods Laboratory testament of UV Turbo for grease removal was done by analyzing exhaust air samples collected from laboratory ventilation duct. Hydrocarbon (C-H) bonds in samples were analyzed with spectroscopy method in Fourier Transform Infrared Spectroscopy (FTIR) machine. Odor removal tests for kitchen exhaust air were done with OMX-SRM Handheld Odor meter according to methodology described in manual. However, field examinations for grease removal were done in two different restaurants. Field tests for odor removal were done in other two restaurants with the same techniques used in laboratory tests. Results and Discussions According to laboratory tests, 14 % grease vapors (approx. < 2 µm) were treated with ozone free UV lamp of 24 W and (51 – 55) % with PCO (UV/TiO2) method. After observations in the real kitchen environment revealed that almost all grease particles deposited on TurboSwing’s walls for 3 years were cleaned during 5 months use of ozone free UV lamp (24 W) and TiO2 coated plates. Similarly, according to laboratory tests for odor removal, approximately 52 % odor was eliminated with this technique and upto 89 % odor reduction was identified in the real kitchen test environment. The results reveal that PCO method removes grease and odor efficiently. The flame tests verified that fire cannot penetrate UV Turbo filter. Conclusions PCO method used in UV Turbo is tremendously beneficial for grease and odor removal. It removes 100 % grease spatters > 2 µm and more than 50 % grease vapors < 2 µm. It eliminates upto 89% odor produced in kitchen. The technique does not consume ozone but TiO2 as green catalyst. It works efficiently with 24 W UV power and has fire preventative capability. Therefore, UV Turbo system is green and safe.

11:54
Designing a High Performance Indoor Environment for a Productive Generation
SPEAKER: Dana Aljadaa

ABSTRACT. In the last few years, educationalist, researchers and ministries have increased the concerns in effect of the indoor environment on students’ performance in schools, and several research have already shown that the Indoor Environment Quality (IEQ) acts as a fundamental issue that cannot be abandoned when aiming to achieve a sustainable school. Consequence of indoor environments attain both the level of productivity and the performance of students while sickness and illness that increases absents. Indoor air quality, natural and mechanical lighting, thermal comfort, ventilation and noise may result in either a healthy and comfortable environment or a noxious uncomfortable domain for students. Considering all aspects of IEQ, it is essential during the early stages of design to achieve a successful workable project, where all IEQ will interact together and affect the building operation. Organization of seating in the classroom and design of the openings will affect efficiency of natural lighting and acoustics; building mass will affect temperature, humidity and air quality; materials whether applied on interior or exterior will affect the IEQ. All these aspects should be considered when designing, monitoring and maintaining during operations to establish a healthy indoor environment for students, which will effect directly their health and performance in the school. The focus of this desktop study is to review literature to find answers to the following questions and illustrate factors that can affect the educational process and productivity of students through the physical teaching environment. What makes a school a productive factory for new generations? How does the physical design of the school effect and have impact on students’ mood, achievements, productivity, personality and comfort? What are the main factors that mostly effect the students’ health, performance and achievement, and how?

11:57
Evaluation of the Indoor Thermal Quality in high schools buildings: strengths and limits of different assessment methods

ABSTRACT. Recent studies have pointed out how much the indoor environmental quality in school classrooms is an important factor which could prevent from serious adverse effects not only on the students’ comfort sensation, but also on their health and learning potential. However, although standards EN ISO 7726:2001, EN ISO 7730:2005 and EN ISO 10551:2001 give recommendations about how to perform practically objective and subjective measurements on the level of comfort in buildings, there is the need to define a systematic way in order to implement comfort assessment through a methodical and uniform approach. In this work the assessment of the Indoor Thermal Quality of three classrooms in two high schools located in Treviso, a town in the North-East of Italy, is presented in order to highlight the strengths and the limits of three different evaluation approaches: field monitoring, survey questionnaires and dynamic simulation. In particular, the research attempts to establish a precise working method in comfort evaluation able to fill the gap that could emerge by implementing each method individually, through the comparison of the three approaches. Two monitoring campaign were performed, the first one during the warm season, in free running conditions, and a second one during the heating period, so as to include different seasonal and management situations. According to the prescriptions of the technical standard UNI EN ISO 7726, objective measurements were performed developing an accurate protocol used for each classroom. Since occupants’ comfort depends on the environmental physical factors, the objective method consisted of physical observations and field measurements of thermal environmental parameters, using a Thermal Comfort Data Logger, for a defined period of time during actual lessons. These data were processed in order to evaluate comfort by calculating at first Fanger’s comfort indices (PMV-PPD) and by applying, then, the comfort adaptive model. The subjective approach was managed, simultaneously with the objective measurements, by giving students and teachers a survey questionnaire about their personal judgment concerning the level of comfort perceived. The survey was accurately and specifically elaborated, starting from the regulation’s directions, in three different versions, in order to pay particular attention to the questions’ comprehensibility for each typology of users: students, teachers, school energy manager. The survey was also used to make some behavioral observations about occupants, their interaction with the environment, their level of satisfaction of school and productivity. Finally, the air temperature measurements have been used to calibrate the simulation model of a chosen classroom in order to calculate the comfort indices to be compared to the measurements and people satisfaction.

10:30-12:00 Session SS 7: Building Technology
Location: Radiosalen
10:30
Optimal Design of Passive Solar Buildings for dormitories in China

ABSTRACT. INTRODUCTION: Heating energy use amounts for 40% of the total building energy consumption in China. To save heating energy, the renewable energy source has attracted our attentions. The passive solar building is a type of low-energy buildings exploiting solar energy to create a comfortable environment in buildings. Numbers of literature has shown that the greatest opportunities for the passive solar building designs occur at the conceptual design level, by determining the values of parameters that have critical influence on building performance, such as building orientation, building type and glazing, etc. Very few studies have focused on the building location and the heat collecting wall. The objective of this work is to achieve the optimized design scheme of the passive solar dormitory in Ruoergai,located in Qinghai-Tibet Plateau of China, for meeting the most basic heating requirements without the use of electrical or mechanical equipment.

METHODS:In this study, building simulation is carried out using EnergyPlus software, the optimization parameters involve the building orientation, building type, window-wall ratio, and heat collecting wall. To determine the building orientation, different conditions are considered. It is proved that the temperature buffer between the building and the outdoor space can improve the indoor thermal comfort, thus the comparisons are conducted to add the temperature buffer on the roof, north wall and west/east wall of buildings. Moreover, reasonable window-wall ratio of the south wall is obtained through comparing diverse schemes. Aiming at balancing the cost and the indoor thermal comfort, three heat collecting plans are examined.

RESULTS and DISCUSSION:With the use of the weather data of Ruoergai, the optimal design of passive solar dormitory has been performed. Results show that when the building faces to the south, the mean indoor air temperature in winter is 1~3℃ higher than that of the building facing other directions. The embedded temperature buffer on the roof, north wall and west/east wall of buildings can obviously improve the indoor temperature, and the extreme minimum indoor temperature can get a maximum increase of 7℃ than those without temperature buffer. When the window-wall ratio of the south wall reaches 0.7, it is efficient to get more solar energy and increase the indoor temperature at night. In terms of investment and thermal comfort, the direct-gain passive solar house with heat collection window can result in the same indoor temperature as the heat storage wall or floor design does. But the former one is more economical and easier to maintain, therefore it is selected as the final scheme.

CONCLUSIONS:For improving the indoor thermal comfort of a passive solar dormitory in Ruoergai, building simulation is carried out to optimize the building design. Results show that the reasonable building orientation can improve the indoor temperature to some extent and installing temperature buffers will significantly increase the mean indoor air temperature. Meanwhile, when window-wall ratio of the south wall reaches 0.7, the direct-gain passive solar house with heat collection window has higher energy saving potential than other schemes.

10:40
Combination of phase change materials with ceiling cooling panels in office environments
SPEAKER: Rita Farkas

ABSTRACT. Consultants: János Szabó, Dr. Zoltán Szánthó from the Budapest University of Technology and Economics, Faculty of Mechanical Engineering

In the international routine, phase change materials (PCM) are mainly used for decreasing the energy usage of buildings. In our paper we investigated a ceiling cooling system operated with phase change materials in an office environment. We analyzed the PCM, the ceiling cooling system and their combination with ANSYS simulations. The aim of CFD simulations was to determine the cooling performance of the panel and to investigate the improvement potentials using PCMs. We made a Matlab program which can calculate the uptime of the refrigerator and its EER in the function of the PCM properties and thickness, the volume and shape of office, the inner heat generation rate, and the ambient temperature. We investigated the process of phase change, the heat fluxes, the effect of radiation, and the temperature of walls and cooling water. In the simulations we determined the optimal melting and solidification points, and the thickness of the optimal phase change materials in different room types to maximize the reduction in annual energy usage. Finally, to validate our results we built a small scale adiabatic room in the department’s laboratory. As a result we could determine the optimal PCM properties, which can maximize the energy reduction of the office building. According to our calculations, simulations and measurements we can state that the usage of phase change materials in office environment can reduce the annual cooling energy usage of the building by 10-20%, depending on the operation conditions.

10:50
Three-scale airtightness study of wooden frame wall assemblies in laboratory
SPEAKER: Nolwenn Hurel

ABSTRACT. Poor airtightness in buildings can lead to an over-consumption of energy and to many issues such as moisture damage and poor indoor climate. The wooden frame constructions are particularly subject to air leakages and further knowledge in this field is needed to meet the regulation requirements tightened by the development of low-energy and passive houses. This paper focuses on a three-scale experimental study carried out in laboratories for that purpose. Walls of specific size, assembly and airtightness defects are tested by measuring the air flow under varying pressure differences. Gypsum wallboards with a 2 cm diameter hole and glass wool layers are tested both separetely and together on two scales (0.15m x 0.15m and 2m x 0.7m) for a rather fundamental approach. The airtightness of a real wall assembly (gypsum board – vapour barrier – wood fiber – MFP) is also tested on a bigger scale (5m x 2,5m) under pressure differences ranging from 20 to 100 Pa. Various sealings of the vapour barrier are studied, as well as the interior and exterior sealings of a triple-glazed window. The results put all together give quantitative informations for more accurate building scale simulations. It also gives a number of recommandations for a better workmanship on the building site to enhance the airtightness. It is found in particular that whether or not the gypsum board and the insulation are glued together has a significant impact on the resulting pressure-flow law. In addition the order in which the wall layers are assembled influences air flow values for high pressure differences.

11:00
6 YEARS of ENVELOPE AIRTIGHTNESS MEASUREMENTS PERFORMED by FRENCH CERTIFIED OPERATORS: ANALYSIS of ABOUT 65 000 TESTS

ABSTRACT. Since 2000, the French EP-calculations have been considering thermal losses due to building envelope airtightness, and most recently since 2008 with the BBC-Effinergie label, and in 2013, with the current EP-regulation (RT2012). They have implemented a limit value for envelope airtightness for all new dwellings, and the mandatory justification of the building airtightness level through either an airtightness measurement or the application of a certified quality management approach. Therefore, there are more and more measurements of building envelope airtightness performed in a regulatory context in France. In order to assess the quality of those measurements, the French Ministry in charge of Construction has implemented a process to certify the operators. This process requires a yearly filling of a standard form which includes, for each measured building, various construction characteristics and airtightness measurement results. Since 2009, Cerema has been gathering the forms filled in by all qualified operators. In 2015, those forms amount to about 65,000 measurements performed on dwellings and non-residential buildings in France. This paper presents an analysis of this database. First, it proposes an overview of the measured buildings characteristics. The second part of this paper presents first analyses on envelope airtightness, including a description of the leaks location. It also presents the evolution of the measured airtightness depending on various parameters such as the date of construction and the volume of the buildings. The last part of this paper gives some feedback about the consequences of requiring a limit value.

11:10
Multifamily buildings air tightness testing

ABSTRACT. The airtightness test is one of a few building envelope measurements used in practice which is quantitative, not just qualitative as e.g. infrared thermography. The airtightness test result may be a measure of the building design and construction quality and could also be used for the energy demand for heating and cooling analyses. Although large number of single family houses were measured during last 40 years, only few results for multi-family residential buildings are available worldwide. Lack of measurement database makes it difficult to assess the energy impact of the infiltration and to formulate guidelines and requirements. Multifamily buildings airtightness tests performing methods and results analysis is the subject of the paper. Review of multi-family buildings market and the presentation of the airtightness measuring methods were provided. Literature review revealed that performing tests and interpreting results are much more complicated in multi-zone buildings than in single-zone ones. Several airtightness test methods were described, theirs strengths and weaknesses were provided. Case studies and measurements of unoccupied two five-floors buildings, one with 47 and the other with 107 apartments, were presented. Building characteristics, test preparation and equipment were explained. First building is equipped with natural ventilation, second with mechanical exhaust. Blower Door airtightness tests were carried out in a few ways: with open and manually closed trickle vents, for whole buildings and for single zones, for zones with adjacent zones pressurized and not pressurized. Results were compared with results obtained with FLiB an ATTMA calculation methods developed for subsidies verification. It was concluded that whole building airtightness value cannot be easily calculated as weighted mean results for separate zones. With adjacent zones not pressurised equally the result is affected with interzonal leakages. Even with adjacent zones pressurised the most difficult to judge is the value of common spaces airtightness, which is often practically impossible to measure separately. The whole building, one zone testing is found to be the only one method resulting in real value for the building, but in parallel it is extremely difficult to measure occupied multifamily building as a whole.

11:20
Development of novel roof finishing materials using PCM for detached houses to mitigate urban heat island and to improve thermal condition

ABSTRACT. In this study, an experiment with a Phase Change Material (PCM) and Wood Plastic Component (WPC) was conducted to mitigate the urban heat island effect in summer and to improve the thermal environment in winter. The urban heat island effect, in which the city temperature is higher than nearby rural areas, occurs due to the increasing population, increased built surface area, anthropogenic heat, and greenhouse effect. The urban heat island intensity varies according to spatial form and temporal characteristics. While various methods can be used to mitigate the urban heat island effect such as using cool roof materials or a green roof system etc., highly reflective roofs have a higher heat loss in winter. Furthermore, the weight of the green roof is considered as a superimposed dead load, which is a disadvantage as it leads to increased construction and maintenance costs. Hence, this study proposed novel roof finishing materials which are applied to WPC deck plates filled with packed PCM to compensate the defects of the cool roof system and green roof system. The thermal conductivity of the WPC deck plate is sufficiently high for the application of packed PCM, while WPC is an appropriate roof finishing material because of its high durability. An experiment was conducted to measure the thermal performance in an external environment in summer weather conditions. The measurements were compared with different melting temperatures and albedo. The n-docosane-PCM, the melting point of which is 44℃, and Bio-PCM, the melting point of which is 26℃ are used to determine the optimal combination of WPC and PCM which is applicable in summer. PCM with the temperature range of 24~28℃ is usually used in the interior of a building. However, in this study, PCM with the melting temperature of 44℃ was used to consider increasing the surface temperature. WPCs with two different PCMs were compared. The temperature of the bio-PCM with a melting point of 26℃ increased continually after phase changing. This means that the sensible heat of PCM was stored after latent heat storage. On the other hand, the PCM with a melting temperature of 44℃ maintained a lower surface temperature than the PCM with the melting temperature of 26℃ because of its higher melting temperature and its latent heat. The result shows that PCM with a higher melting temperature is more effective in controlling the surface temperature and mitigating the urban heat island.

11:30
Structures that include a semi-outdoor space: Part 1: Energy performance

ABSTRACT. The purpose of the present study is to investigate the effects on the energy use of a building when adding a shield, which covers partly or entirely a building, thus creating a semi-outdoor space. There are many structures of this type worldwide, such as arcade-type markets, stadia, second-skin façades, geodesic houses, glass houses, etc. however, there are few studies regarding their energy use and the effect of the semi-outdoor space on the energy demand of the building. In order to investigate that, two case studies were examined: EMBRACE, designed by students of the Technical University of Denmark for the Solar Decathlon Competition Europe 2014, which is a two-person dwelling of 63m2 located in Universe, Nordborg, and Dome of Visions (DoV), which is a two-person dwelling of 84m2 located in Soren Kierkegaard’s Square in Copenhagen. The investigations consisted of simulations in IDA ICE software. Both buildings were simulated in two versions; without shield and with the addition of the shield and the semi-outdoor area created. The results of the two versions were compared in terms of peak load and energy demand, for three different cases; during heating season, during cooling season and during cooling season while implementing natural ventilation. During heating season, in EMBRACE the peak load was reduced by 2% and the energy demand by 3%, while in DoV the reduction was 16% and 37% in peak load and energy demand respectively. During cooling season, in EMBRACE the energy demand was not affected, but the peak load was reduced by 12%. In DoV the peak load was increased by 37%, while the energy demand more than doubled. However, during cooling season with the implementation of natural ventilation, in EMBRACE the peak load was reduced by 31% and the energy demand by 15%, whereas in DoV the reduction was 35% and 62% in peak load and energy demand respectively. EMBRACE and DoV are not directly comparable since the two buildings are different constructions, with different shield shapes and the way they are connected to each building, as well as having different insulation levels. Nevertheless, both buildings appear to be positively affected by the addition of the shield. In both DoV and EMBRACE, the shield resulted in lower heating demand. Regarding the cooling demand, it was not affected in EMBRACE, but it was increased in DoV, as DoV is completely enclosed in its shield, thus a greenhouse effect was created. However, when implementing natural ventilation, the greenhouse effect was eliminated and the cooling demand was further reduced in both buildings. In conclusion, it was proven that by adding the shield and creating a semi-outdoor space the heating load was reduced and so was the cooling load when natural ventilation strategies were implemented.

11:33
Structures that include a Semi-Outdoor space: Part 2: Thermal Environment

ABSTRACT. The thermal environment of buildings with a second "skin" and semi-outdoor space is examined in the present study. A literature review was conducted on similar structures. Very few studies were found focusing on the thermal environment. Two different building case studies were chosen with different building and shield geometry, different levels of insulation but same shield material. EMBRACE, designed by students of the Technical University of Denmark for the Solar Decathlon Competition Europe 2014, which is a two-person dwelling of 63m2 located in Universe, Nordborg, and Dome of Visions (DoV), which is a two-person dwelling of 84m2 located in Soren Kierkegaard’s Square in Copenhagen. Both buildings were modelled in IDA ICE 4.6.2 simulation software in order to assess the thermal environment of the building and the semi-outdoor area and assess how long the semi outdoor space of each building can be used by the tenants. Since existing standards such as DS/EN 15251 and DS/EN ISO 7730 are not applicable for semi-outdoor spaces, an alternative method was followed. An adjustable clothing level from light summer to winter clothing was chosen, in order to resemble the different layers one could have while being in the semi-outdoor area. Also, an adjustable PMV range was set in order to resemble the different tolerance occupants could have while being in such a space. The three examined ranges were: a strict range -0.7

11:36
Indoor environment in a high-rise building with lightweight envelope and thermally active ceiling
SPEAKER: Dusan Petras

ABSTRACT. Retrofit of the envelope of the 23-floor high-rise office building of the Faculty of Civil Engineering in Bratislava was carried out recently. In this building, a thermally activated ceiling system, also called CRITTALL, is used for heating in winter and for cooling in summer. The aim of this study is to evaluate the indoor environment quality in a high-rise building conditioned by such thermally activated ceiling system after the façade and heating system retrofit. The original facade constructed from prefabricated panels consisting of a steel frame, float glass and opaque parts of the parapet was replaced by new prefabricated aluminium blocks. The technical room supplying heat to the high-rise building was significantly reconstructed consequently. Retrofit was supposed to improve the physical conditions, as well as to help reduce the operation costs of heating. Simultaneously, the new facade should help improve thermal conditions in the offices, which had either not been satisfactory. Representative spaces were selected and equipped with sensors for monitoring the room temperature, surface temperatures, relative air humidity, outside weather conditions, etc. Presented are the data obtained in the four reference rooms in 2014, sorted out according to the working hours (8:00 AM - 4:00 PM) and assessed in accordance with the current standard EN 15251:2007. Indoor air temperature, air quality and humidity were considered as the indicators of indoor environment quality of the high-rise building. The outside weather conditions, solar irradiance, changes in internal heat gains and small heat accumulation capability of the light-weight facade can result in relatively dynamic changes in thermal balance of the building. Due to the high time constant, i.e. slow reaction of the thermally activated ceiling, the heating system may not be able to respond to these changes fast enough to assure a comfortable thermal environment. The results indicate overheating of the rooms, in particular during transition periods and in offices with double skin façade oriented to the South-West. Although this cannot be completely eliminated, a partial remedy could be proper hydraulic balancing and a more sophisticated control of the heating/cooling system, e.g. control according to indoor air temperature in the reference rooms.

11:39
ANALYSIS OF PROCEDURE FOR USE OF SOLAR ENERGY FOR BUILDINGS RESIDENTIAL ASSESSMENT.

ABSTRACT. This article aims to evaluate the methods used solar energy in residential buildings. The application of some technologies introduced recently in the construction industry has generated questions about how to install and use for the quality of the buildings with the human thermal comfort of the resident. For the analysis, we adopted a unifamiliar building to the climates of the states of São Paulo, Rio de Janeiro and Roraima. Evaluation thermal performance of the building will be based on NBR 15575-1 and human thermal sensation method of Fanger. The research examined the influence of solar insolation conditions, shading, air renovation and floor of the original building in contact with the ground on the result of thermal performance for summer and winter. Finally, we applied the proposed new design procedure with the use of solar energy technology to evaluate the thermal performance of residential buildings. Comparisons between the two procedures current residential project and modifications covering the human thermal sensation indicates that the changes in solar technology conditions have a strong influence on the results of human thermal comfort simulations of the building and, consequently, the system approval in constructive analysis.

11:42
Experimental Study on the Dynamic Heat Transfer Characteristics of Triple-pane PCM-filled Window
SPEAKER: Shuhong Li

ABSTRACT. In order to reduce the heat transferred into the indoor environment in the discharge period of PCM and to reduce the overheating risk after the PCM has melted completely, the triple-pane PCM-filled window (TW+PCM) is proposed. Paraffin MG29 is filled in the TW+PCM. The comparative experiment of the TW+PCM, the double-pane PCM-filled window (DW+PCM) in the sunny summer day and rainy summer day is conducted. The thermal properties of the TW+PCM are obtained. The results of experiment show that in the representative sunny summer day, the peak temperature on the interior surface of the TW+PCM is reduced by 2.7℃, and the heat entered the building through the TW+PCM is reduced by 16.6%, comparing with the DW+PCM. The TW+PCM plays a significant role in decreasing the peak temperature and peak heat flux on the interior surface and reducing the heat entered the building through the TW+PCM. It also shows a good performance on the delay of peak-temperature time, the same with the DW+PCM. In the representative rainy summer day, the TW+PCM has a good performance of reducing the temperature fluctuation of the interior surface and the heat transferred through the TW+PCM, but it is unsatisfactory to reduce the peak heat flux on the interior surface and delaying the peak temperature.

11:45
Modelling of Electrically Activated Thermal Mass

ABSTRACT. Application of thermal mass activation (TMA) is not a new approach to heat/cool buildings. In 1937, in Switzerland, a building was constructed with embedded steel welded pipes in a concrete floor slab. Recently, TMA has attracted attention due to the potential benefits it can offer in terms of energy efficiency, particularly for shaving and/ shifting the load from peak to off-peak periods, emergency heating/cooling load, and for its economics and environmental impact. Shifting from peak periods to off peak periods can be done by electrically activating the concrete slab; i.e.: placing electrical resistance into the concrete slab. Integration of this technology in Canadian residential buildings for the purpose of shaving or shifting thermal load is a challenging issue, as these buildings are located in a cold climate and are lightweight constructions and the main floors are made up of plywood and have no thermal mass. However, almost all residential buildings have a basement, and the basement is furnished with a slab concrete floor. The challenge is to use the concrete heated floor as TMA.

The main challenge is to place the TMA in the basement floor slab and store energy during off-peak periods. In turn, this stored energy can be released during peak periods in order to provide the required indoor thermal conditions in the living areas, which are located on the main floor. In this regard, a considerable amount of energy is needed to condition both storeys of the house during the peak periods, and associated with this is relatively thick assembly comprised of both insulation and concrete with electrical heating wires lodged in the concrete. This paper addresses the behaviour of proposed electrically activated slab assemblies in design operations as well as in maximum operating conditions. The maximum and minimum allowable thickness of insulation and concrete will be based on risks of overheating the electrical heating cables as well as the potential for storing thermal energy. The prediction of the dynamic behavior of the system is carried out numerically. The design and calculation of the heating capacity depends mainly on the distance between heating elements, thickness of the concrete slab above/below heating elements, surface material, thickness of thermal insulation above/and below heating elements, etc.

11:48
Analysis of the effect of a rooftop greenhouse in building indoor temperature and acclimatization needs using building energy simulation
SPEAKER: Ricardo Gomes

ABSTRACT. Building-Integrated Agriculture has the potential to offer a new dimension to our buildings, providing locally grown food that increase urban resilience. This paper relies on the Rooftop Greenhouses (RG) solution, in particular its effect in the indoor temperature and its acclimatization needs on the last floor of one Portuguese 1960s building. The analysis is based on the building energy simulation of different scenarios. The simulation of the base scenario shows that the installation of a RG results in overheating that is translated in an increase of 232% in the number of annual hours of indoor temperature above 26ºC on the building last floor. The alternative scenarios to avoid this situation considered the slab thermal insulation, night air ventilation enhancement on summer and changing the indoor temperature setpoint of the RG. The simulation results highlight that all the scenarios proposed result in a decrease (comparing with the base scenario) of the cooling needs, being the slab insulation the most effective isolated measure. Even so, the implementation of a RG in this building typology will increase total acclimatization needs of the apartment below.

11:51
Performance evaluation of two cross type indirect evaporative air coolers

ABSTRACT. A comparative analysis of two types of cross flow indirect evaporative coolers (IEC) is presented: a typical IEC and a regenerative IEC. A part of primary air exhausted from regenerative IEC is supplied into secondary air channel to sensibly cool the primary air to its dew point temperature. The purpose of this article is to analyze the performance of two indirect evaporative coolers under the constant inlet air temperature and humidity with variable air flow rates. The hot and dry outdoor air condition is selected as inlet primary air condition which represents the condition of dehumidified air exhausted from liquid desiccant unit in summer. To compare the cooling capacity of typical IEC and regenerative IEC, primary air flow rate of regenerative IEC is adjusted in two modes: 1) equal primary air flow rate with typical IEC, 2) primary air flow rate considering extracted secondary. The performances of two types of IEC are evaluated through experiments in environmental chambers and then validated with analytical models. The experiments are conducted with two environmental chambers that one provides the outdoor air condition while the other makes the indoor air condition. The analytical models are established with ε-NTU method using the heat transfer coefficients measured from experimental data. As a result, the typical IEC showed highest wet bulb efficiency of 52% while that of regenerative IEC was 36% when supplied with more primary air flow due to extracted secondary air.

11:54
Analysis of Ideal Absorption Cycle with Support of Solar Energy and the Use of Working Solutions H2O/LiBr and NH3/H2O

ABSTRACT. This paper presents of a comparison of two single-effect ideal absorption chillers lithium bromide/water and ammonia/water using like working solutions. In each part of component of the system are analyzed based on pressure, mass flow, enthalpy, concentration refrigerant and sorbent. The same cooling demand has been chosen for absorber, generator, condenser and evaporator in both cases. Selected input data, resp. the temperature gradient was selected on the basis of the most commonly used temperature gradient in practice. Used input data for both working solutions particularly affect energy efficient ratio (EER), where ammonia/water works with lower EER than working substance lithium bromide/water. The performance of generator works with higher efficiency with ammonia/water.

11:57
Comparison of different PCMs impact on indoor comfort in a energy positive house
SPEAKER: Andrei Bejan

ABSTRACT. Phase change materials (PCM) can be an efficient way to improve indoor comfort and to reduce the energy consumption. To study the impact of different PCMs on thermal comfort we have used the EFdeN House Project which is a research and educational project representing Romania at Solar Decathlon Europe 2014 from Versailles, France. The EFdeN house proposed the implementation of several active and passive strategies. These performant and innovative strategies were designed in order to obtain the perfect indoor conditions and desired comfort with minimum energy consumption. Using these strategies, the prototype became an energy plus house, which produces more energy than it consumes and it has the features of a passive house. One of the most innovative solutions implemented in the EFdeN prototype was the integration of phase changing materials (PCMs) in the building interior and exterior walls. Using multiple simulations realized using the Energy Plus engine for the Bucharest climate (hot during summer and cold during winter) we have obtained several interesting conclusions. The house was constructed as a light structure with steel and wood panels. Inside the walls, terrace and floor multiple layers of insulations (20 cm to 40 cm) were installed in order to have an energy efficient construction. A 3D model of the house, its function and systems were numerical modelled and simulations were launched. We have determined, that, during a summer day, the fluctuations of the temperatures for a room with PCMs type M27/Q23 in the walls are lower than for an ordinary case, without PCMs. This material has a latent heat storage value of 85 Wh/m2 and a phase change temperature of 23°C. The difference in amplitude of temperature variations between the two cases is about 0.6°C and we could observe a difference of 1.7 °C for peak moments. Moreover, in a typical summer day, the temperatures are lower when using PCM. We also observed that the impact of PCMs on interior comfort conditions is more important if the material has a higher latent heat storage and the phase changing temperature near the interior setpoint. We have conducted other tests with different PCM materials and the best one was found to be the PCM type M182/Q25, with a latent heat storage of 574 Wh/m2 and a phase changing temperature of 25°C and which had a great impact on indoor comfort: a difference in amplitude of temperature variations of 1.3°C and a difference of 2.2°C in the peak moment. During winter, the impact of PCMs on indoor comfort is lower because of the highly insulated house. We also have conducted several tests with different PCM materials and the best one was found to be the PCM type M182/Q25 which had a good impact: a difference in amplitude of temperature variations of 0.5°C and a difference of 0.5°C for the peak moments. Moreover, in a typical winter day, the temperatures are higher when using PCM because of the thermal mass, the EFdeN house having a light structure. The improvement of temperature variations when using different types and amounts of PCM can greatly vary for an energy efficient house based on variable scenarios (occupancy, ventilation rate, internal gains and temperatures set-points).

10:30-12:00 Session WS 19: Building automation and control systems: continous operational energy use optimization (REHVA & eu.bac Task Force)

Organiser: REHVA - eu.bac joint Task Force on Building Automation and Control Systems (BAC)       


Presenters:

Organisers/moderators:     Andrei Litiu and Peter Hug - eu.bac

Speakers:    

  • Bonnie Brook - eu.bac
  • Stefano Corgnati - REHVA
  • Simona D’Oca - REHVA
  • Valentina Fabi - REHVA
  • Roland Ullmann - eu.bac

 

Scope:

The aim of the workshop is to interactively discuss about the before mentioned issues and what practical tools can be used to overcome them and ensure building automation and control systems deliver their multiple benefits promises. The workshop will include the presentation of several certified building(s). 

Full description of workshop at: http://www.rehva.eu/?id=1121

Location: Bondestuen
10:30-12:00 Session WS 20: How to improve the quality of the works and compliance of Energy Performance Certificates? (QUALICHeCK)

Organiser: QUALICHeCK


Presenter:

Chairperson: Peter Wouters

 

Scope:

To address these quality and compliance challenges, the objectives of this workshop are to discuss the following questions:

  • What is the status on the ground in terms of quality and compliance?
  • What steps could be taken to improve the situation?
  • What are key aspects to consider for effective compliance frameworks?

Full description of workshop at: http://www.rehva.eu/?id=1110

Location: Harlekinsalen
10:30-12:00 Session WS 25: Total Concept method for major reduction of energy use in non residential buildings (EU H2020 Total Concept)

Organiser: EU Horizon 2020

 

Speakers:

Introduction to Intelligent Energy Europe project the "Total Concept" (Alireza Afshari)

Main steps of the Total Concept method implementation (Mari-Liis Maripuu)

The economic principles of the Total Concept method (Åsa Wahlström)

The Total Concept method implementation in the Nordic countries- outcomes and lessons learned (Mads Mysen)

 

Short description:

In order to reach the 20-20-20 EU-targets it will be essential to increase the ambitions by the building owner´s to carry out major energy refurbishment projects in the non-residential building sector. In existing non-residential buildings energy savings can often be achieved by improving the building envelope and the performance of HVAC systems and other energy requiring installations. In addition, changes in user behavior can be effective - without loss of comfort. However, if the measures are to be carried out in practice then they would have to comply with the property owner’s or client’s terms and conditions for long–term investments. Total Concept offers a method and a economic tool that can provide the information required by establishing a platform for decisions on investments in energy-saving measures. The method applies a refined systematic approach to the work with energy issues in buildings, with the aim of achieving maximum energy savings in a cost efficient way and to motivate building owners to take a step further and make decisions on larger investments. A European cooperative venture has been established, involving Sweden, Norway, Finland, Estonia and Denmark, to further develop the method and to test the concept in the various national contexts. The aim is to establish a reliable market driver for major renovation projects that can lead to considerable energy savings in the building sector. Since the non-technical barriers influencing the renovation rates can be somewhat similar also in other European countries, it will be possible to transfer the method also to other countries. The workshop covers the identified main non-technical barriers in the renovation market in northern European countries and how the Total Concept method could be a solution to overcome these barriers. The results of Total Concept method implementation in the Nordic countries are presented and possibilities for increasing the number of larger energy renovations of non-residential buildings will be discussed.

Location: Latinerstuen
10:30-12:00 Session WS 29: Occupant Behaviour (IEA EBC Annex 66)

Organiser: IEA EBC Annex 66: "Definition and Simulation of Occupant Behavior in Buildings"

www.annex66.org  

 

Speakers:

Andreas Wagner (KIT, Germany): Experimental approaches for collecting occupant behavior data in the field and in the lab

Ardeshir Mahdavi (TU Vienna, Austria): New modeling approaches and quality assessment for occupant behavior models

Rune Andersen (DTU, Denmark): Application of occupant behavior models in building energy performance simulation for improved design and operation of buildings

 

Short description:

Occupancy behavior in buildings is of growing importance for building design as well as for building operation and performance optimization, as it turned out to be one of the leading influences on energy consumption in buildings. Occupancy behaviors are either random, or purpose-driven (e.g. entering/leaving a room, consuming domestic hot water, using an appliance) or comfort-related (e.g. adjusting a thermostat, opening a window for ventilation, closing blinds). They change the indoor environment in terms of temperature, humidity, illuminance levels, air quality etc. which influences total energy consumption of a building. As building services systems and their controls are becoming more complex and sophisticated, occupants are often not aware of the relation between their actions and their influence on energy consumption.

The challenges to model and predict occupancy behavior in buildings are: (a) occupancy behavior is stochastic and complex in nature; (b) monitoring occupancy behavior relies on various sensors with relatively high costs; and (c) privacy issues make data collection difficult. Hence, there is a lack of consistent data from real-life building operation and therefore state-of-the-art models used in the planning practice simplify user-related actions and mostly underestimate their impacts. There is a strong need for improved and more accurate approaches of modeling occupant behavior as well as for integrating these models into building simulation programs in order to support planners and building managers during the design phase and building operation.

This issue has been raised in the IEA Annex 66 Definition and Simulation of Occupant Behavior in Building and researchers contribute to different tasks and activities in this context since the beginning of 2014. The workshop will introduce into three major areas of the Annex work in order to open discussions between researchers and practitioners about the necessity and the best strategy to implement occupant behavior in building design and operation.

Location: Laugstuen
10:30-12:00 Session WS 31: Advanced airflow distribution methods for reduction exposure to indoor pollution (Scanvac)

Organiser: SCANVAC
 

Presenters:

Chair: Guangyu Cao

Speakers:

Prof. Guangyu Cao, NTNU, Norway

Prof. Arsen Melikov, DTU, Denmark

Prof. Risto Kosonen

Prof. Peter Nielsen

 

Scope:

The main objective of this workshop is to discuss various methods to improve indoor air distribution to prevent the occupants from exposure to various indoor pollutants.

Full description of workshop at: http://www.rehva.eu/events/clima-2016-workshops/ws-25-advanced-airflow-distribution-methods-for-reduction-exposure-to-indoor-pollution.html

Location: Columbinesalen
13:30-15:00 Session SS 15: Energy Flexibility & Storage
Location: Det Lille Teater
13:30
Dynamic building energy demand modelling at urban scale for the case of Switzerland
SPEAKER: Danhong Wang

ABSTRACT. It is well known that the energy consumption of buildings for heating, cooling and electricity varies significantly over time, building type, usage and user behaviour. For the integration and balancing of production and consumption of intermittent energy from decentralized sources, detailed knowledge on energy demand profiles of buildings in a district or at the urban scale is highly required. Modelling each building individually by using bottom up methods, with certain level of building details is time consuming, computational expensive and case specific, especially not flexible with subsequent building level modification when dealing with thousands of buildings. Most recent studies for bottom up modelling methods usually rely on modelling typical buildings to represent the entire building stocks at urban scale. However detailed geometric differences, building orientation and external shading by neighbor buildings are in this case neglected.

This paper presents a new methodology to automate the process of modelling and simulating buildings energy performance at a large scale for the case of Switzerland. First of all, accessible building geographical information from swiss building geodata are pre-processed through ArcGIS, defining the geographical coordinates for the floorplan vertices. Based on actual building floorplan, 3D thermal zones including external shading by neighbouring buildings are created. Secondly, according to Swiss building statistics and Swiss standard SIA 2024, other non-geometry related building characteristics are identified, such as user behaviour, building type and usage, etc. Therefore, for each building, a complete Energy Plus file is automatically generated. Subsequently, a dynamic hourly based load profile is calculated automatically for each building in an urban district. The methodology provides a flexible approach that can be easily applied to simulate the energy demand for any district in multiple scales with adequate building information inputs. With this approach, the modelling time can be significantly reduced, assuring detailed enough modelling accuracy. To validate the methodology, a case study comprising 112 residential building in a small village in Switzerland is selected and modelled by using this approach. Compared with accessible measured yearly heating demand data, the simulated results show a slight overestimation of about 10%. This method can be used to not only deliver building energy profiles but also to evaluate different retrofitting strategies and climate change scenarios for buildings within an urban area.

13:40
Building's Energy Flexibility towards nieigborhood level for Smart grid support
SPEAKER: Wim Zeiler

ABSTRACT. Using the flexibility within energy generation, distribution infrastructure, renewable energy sources and the built environment is the ultimate sustainable strategy within the Built Environment. However, at the moment this flexibility on building level is still to be defined. The new IEA Annex 67 is just starting work to define this specific flexibility. Our research is aimed at developing, implementing and evaluating new process control strategies for improving the energy interaction within the building, its environment and the energy infrastructure by effectively incorporating the occupants’ needs for health (ventilation) and comfort heating/cooling). An integral approach based on General System Theory is used which divides the whole system in different layers from user up to centralized power generation. A bottom-up approach, starting from the user up to the Smart Grid, results offers new possibilities for buildings’ energy flexibility. To make use of the dynamic possibilities offered by flexibility of new intelligent process control concepts are necessary. Multi Agent Systems in combination with Building Energy Management Systems can offer the required additional functionalities. The approach is tested in a case study building.

13:50
Next Generation Building and District Metrics to Enable Energy Systems Integration
SPEAKER: Paul Beagon

ABSTRACT. Traditional building performance metrics consider a building as a standalone and static utility consumer. Voluntary green building certifications of districts generally aggregate the metrics of standalone and consuming buildings. There is a lack of performance metrics concerning the integration of critical services to a building and the utility networks supplying these critical services of electricity, natural gas and water. In order to achieve integration of energy systems, including storage based demand side management and rain water harvesting, a methodology is modelled for a typical office. The methodology requires building parameters to be combined and manipulated in order to create the proposed performance metrics. The building model is simulated for three periods of interest: a whole year, a winter design day, a summer design day. The proposed metrics enable operational management during peak and standard loads, as well as longer term analysis of the building performance. Operational management includes the role of storage and the responsiveness of a building during demand ramping or shedding. Over the longer term, the metrics indicate efficiency trends and guide design and investment decisions. It is found that electrical storage combined with demand side management reduces energy costs with no service disruptions. Rain water harvesting is also found to significantly reduce financial and energy costs, and given its current dearth of deployment, has high future potential.

14:00
A Procedure to Predict the Energy Demand Profile of District System

ABSTRACT. The ever-increasing demands for heating in different sectors, along with more preventative regulations on greenhouse emissions, have compelled designers to seek new alternatives to design energy-efficient buildings. One of these alternative approaches is the Community-District System (CDS). Different methods have been proposed for improving the energy efficiency of CDSs. One of these methods focusses on decreasing peak demand load and regulating energy consumption via energy management. In order to implement this approach it is essential to predict the detailed energy consumption profile of the CDS. Several methods have been developed to model the demand profiles of CDSs. In a small-scale systems, due to the small number of users, the energy demand profile will be predicted by the detailed-modeling of the users using different energy simulation software whereas in large district scale system, due to large volume of users, a comprehensive modeling of the users is time consuming and can be unfeasible. To overcome this problem, a variety of simplified models have been developed and utilized by designers. One of the main drawbacks of the existing simplified models is that they mostly determine the total energy consumption of the users as opposed to the detailed annual profile of the energy consumption. This paper describes the development of procedure to predict the energy consumption profiles of the large-scale CDS. This model have been validated by comparing the model prediction with the results obtained from simulation of the community scale CDS using comprehensive model.

14:10
Development of A Scheme for Assessment of Demand Response Potential Using Distributed Sensor Networks for Residential Flat
SPEAKER: Borui Cui

ABSTRACT. Demand response (DR), which is the change of electricity use of demand side during times of peak demand, is a cost-effective mean of relieving the imbalance issues on the power grid. The residential ACs are excellent DR resources to deliver considerable power reduction without significantly affecting thermal comfort of residents. This research provides a scheme for assessment of demand response potential of residential ACs in flats. The essential part in the framework is the developed adaptive and self-learning building thermal model, which can be applied in residential buildings with different characteristics. GA algorithm is used as model training method. The thermal model is used to predict the AC power consumption by introducing the predicted outdoor meteorological parameters. Reliable time series based outdoor temperature and solar radiation prediction methods are developed accordingly. AC power consumption and thermal comfort analysis with different indoor temperature set-points can be then performed. The scheme is implemented in a server which also collects the real-time measurements from the sensor block and the Hong Kong Observatory. The optimal control setting recommendation is then sent to the residents’ mobile devices through Wifi.

14:20
Controller Prototyping and Validation for Photo-Voltaic Comfort Cooling Plant

ABSTRACT. Introduction Large office buildings - typically with glass fronts - often suffer from a high cooling demand during summertime. Typically, this requires a large amount of additional electricity for the cooling system. One straightforward alternative is to store cooling energy using electricity generated by solar cells, and this paper investigates, demonstrates and validates the feasibility of providing energy efficient comfort cooling with a low environmental impact, while offering flexibility to the electrical grid. Also, the possibility of reusing unmodified existing CTS systems is investigated. Finally, the possibility of providing improved comfort through intelligent supervisory control is studied. The system is comprised of a grid coupled photo-voltaic system, a heat pump, an ice bank and a cooling coil to interface the existing ventilation system in the office building.

Method This feasibility study was carried out by developing and deploying a prototype system in an existing office building. High level behavioral modeling of major components in Simulink® formed the initial foundation for a system model, while more detailed models were used for simulation of the derived control algorithms. The derived behavioral models in Simulink® were used for direct code generation to the target platform. Major KPIs were COP, electricity consumption from the grid and indoor temperature stability. The study involved one university and five companies (grid, heat pumps, solar cells, building owner, sensors).

Results During this feasibility study a prototype control system was developed and deployed on a Linux platform and all physical components were installed and tested on-site. Initial test of the photo-voltaic comfort cooling system showed a COP-value of approx. 4. Initial test scenarios showed that the capacity of the ice bank can be further minimized than proposed by the supplier. Furthermore, solar panels and heat pump alone were able to deliver enough cooling during a warm summer day and simultaneously charging the energy storage. The cooling effect applied to the office building during office hours was limited by requirements to the lower inlet temperature and we thereby showed the necessity of storing energy to facilitate cooling at night when the solar panels do not provide electricity. During the initial test period the employees working in the office building had a nice comfort level with a temperature fluctuation of less than 2 degrees during office hours on a warm summer day.

Discussion The costs of the plant can be improved in several ways: The ice bank showed to be over dimensioned in the specific scenario. Also, weather forecasts should be exploited, and the number of sensor inputs can be reduced. Furthermore, a simpler control schema will reduce the deployment costs. Finally, the plant showed high flexibility to offload the electrical grid, i.e. it may exploit the market price variations.

Conclusions By combining solar cells, ice storage, heat pump, a simple control algorithm and an existing ventilation system, the feasibility of providing energy efficient comfort cooling with a low environmental impact and good comfort has been demonstrated.

14:30
EFFICIENT INTERACTION BETWEEN ENERGY DEMAND, SURPLUS HEAT/COOL AND THERMAL STORAGE

ABSTRACT. Buildings account for about 40 % of national energy consumption, and hospitals represent about 6 % of the total energy consumption in public buildings in Norway. Hospitals are the building category with the highest specific energy consumption. A large university hospital uses twice as much energy per square meter compared to commercial buildings. Large university hospitals recently built in Norway have annual energy consumption between 300-400 kWh/m2.

Conversion and utilization of surplus heat sources represent well-known technologies and are under constant development. In large building complexes, with many thermal energy streams, there is a significant potential for coordinated production, storage, and distribution of energy.

Our study has developed new methods for the operation of interacting simulating models. These methods provide tools to step into optimization of combinations of integrated energy systems. The main design issues we address are hydronic flow system and the sizing of storage systems. The hydronic layout is important with respect to utilization of exergy i.e. water temperature, but we also show the importance of control strategies on energy savings. A proposed new hydronic layout and control design are described in this paper, as applied to heating, cooling and storage systems.

Surplus heat or cold streams in large hospitals come from internal loads like equipment, lighting systems, related to occupancy and carried by refrigeration or ventilation systems. The potential for energy synergy in these buildings is dependent on the available surplus heat/cool source at a given time. For building types, such as hospitals, where the need for heating and cooling are high and not necessarily matching the surplus heat and cool production, thermal storage is the most relevant technology to leverage the advantages of heat pumps and chillers.

Research on thermal storage solutions for hospitals has mainly focused on the storage system and not considered the total energy system. We have analyzed different temperature levels for supply and return heating water system as a function of outdoor temperature, different temperature levels for cooling supply and return, and design parameters for the geothermal storage volume. System efficiency will sub- optimal if interdependence of these subsystems is not considered.

Through the simulations and modelling, we show how cascade (serial) connections for heating consumers will optimize the use of the heatpump/chiller plant and reduce the energy consumption significantly. We also show how higher design temperature for ventilation cooling coils and local fan coils can optimize the borehole specification.

Further, we show how interactions between building envelope, climate, local heating, ventilation heating, local cooling, ventilation cooling, lighting, equipment energy, pump and fan energy, and domestic hot water can be exploited to optimize energy performance for a reduction of the total energy consumption of 20-50% in a new hospital.

14:40
Load Balancing Potential of Ground Source Heat Pump System Coupled with Thermal Energy Storage: A Case Study for Berlin

ABSTRACT. INTRODUCTION Fast growing adaptation rate of renewable electricity mainly through windmills, causes high rates of fluctuations and electricity surplus in power grid network and energy utility. Considering the diversity of demand sides in residential sector including space heating and domestic hot water and their high load shifting potential, electrification of heating sector through heat pumps is seen as one of the most promising solutions for flexible demand side management.The aim of this research is to evaluate and optimize the role of heat pump with thermal storage mechanism within a load management strategy in energy network. A Surplus (off-peak) load management scenario through large scale ground source heat pump system coupled with heat storage is presented to offer the flexibility by time shifting of thermal demand of multi-family building and harvesting electricity surplus generated through integration of wind power. By considering different scenarios the role of thermal storage in load shifting and peak shaving of demand profile is evaluated. The case study is carried out for Berlin within German electricity network to increase the possibility of adaptation of more wind power in energy market.

METHODS Basically in this research the load management scenario is implemented in a heat pump and heat storage model developed in TRNSYS. This system supplies domestic hot water and space heating demands of a multi-family residential building, the simulation is carried out for different weather conditions during the heating season. By applying the norms, the reference consumption profile of the building is calculated based on day-type-categories. Considering the excess electricity profile of the low voltage power grid and demand profile of the building, the available daily off-peak hours for the heat pump is determined. System dimensioning is carried out based on distribution and availability of off-peak hours and daily peak demand. RESULTS AND DISCUSSION Comparing this optimized system with a base case scenario where system model performs under normal control conditions, the advantages of the proposed system under off-peak load management is introduced. Thermal diagrams of the system represent the least possible deviation of supply temperatures (±2) from considered set point temperatures; this proves the high potential of the excess electricity source in winter time to fulfill the thermal demand of the residential complex. The monthly off-peak performance ratio of the heat pump represents the ratio of the off-peak performance hours of heat pump over the entire operational hours of heat pump, this factor proves that within the simulation period over 75% of the heat pump electricity demand is utilized by electricity surplus. The results also show that monthly distribution of the excess electricity despite of less overall annual excess power effects the performance of the system. CONCLUSION Applying this method gives the possibility to reduce the share of conventional power supply and adapt more renewable electricity in energy grid; Furthermore it has considerable environmental impacts such as large CO2 mitigation by reducing traditional primary energy sources such as fossil fuels.

13:30-15:00 Session SS 2: Building Retrofit
Location: Europahallen
13:30
Re-commissioning Energy Conservation Measures in Supermarkets: An UK Case Study
SPEAKER: Salvador Acha

ABSTRACT. Considering the UK’s ambitious carbon emission reduction target (i.e. reducing CO2e emissions by 80% below 1990 levels by 2050), it is evident that energy conservation measures in food retail buildings can substantially contribute in meeting this goal. Supermarket buildings in particular are complex energy systems that require careful study to make sure they perform in a sensible manner. Retail pressure on quick store delivery makes commissioning teams prone to mistakes and therefore, despite stores being newly built or refurbished, their systems are not ideally set up. This circumstance makes buildings underperform by excessively consuming energy which is a detriment in terms of costs and carbon emissions. The objective of this paper is to disseminate the energy savings that can come from low cost re-commissioning measures linked to best operating practices; this is achieved by gathering insights from the monitoring of refrigeration, HVAC, and lighting systems. A case study in a 3,300 m2 UK supermarket showcases the energy performance of these systems before and after measures are implemented. The trials conducted have the feature of being holistic by working closely with store staff and contractors. Results show store energy use in Year 2 improved by 20% against its benchmark (Year 1); consequently reducing the carbon footprint and energy bills of the building. Furthermore, the learning’s are transferable and have quick payback periods; thus making clear a large potential exists in reducing energy bills of retailers while simultaneously contributing to carbon mitigation in the UK.

13:40
RENOVATION OF A MULTI-FAMILY BUILDING IN SWEDEN – ANALYSES OF ENERGY SAVINGS, LCC, LCA AND CO-BENEFITS

ABSTRACT. The EU 2020 energy and climate targets demand major initiatives from the building sector. To meet these targets energy efficiency of the existing building stock must be drastically improved. Within IEA ECB Annex 56 (Cost effective energy and carbon emissions optimization in building renovation) one of the main objectives is to provide best practice examples. One example is the energy retrofit of a multi-family building in Sweden, built in 1971 and representative of the Swedish "million homes program". The programme led to a million homes being built in ten years, from 1965 to 1975, and most of them with a high energy use. Many of these homes are currently in major need of renovation and are one of the reasons why investments in rebuilds have increased in recent years. This represents an excellent opportunity to make these homes more energy-efficient. The studied pilot project was thoroughly renovated in 2009.

The aims of this project were to determine the energy savings LCC, LCA and co-benefits of a major renovation. The energy use for different energy measures were calculated using a dynamic energy simulation tool. LCA, LCC and cost effectivity were determined from cradle to grave using the methodology developed within IEA ECB Annex 56.

The result of the renovation is a substantial improvement of the standard of the building and a substantial reduction of the energy use, 65 %. This with preserved architecture. The standard improvements included new installations, new bathroom and kitchen, new surface finish. The energy savings measures included adding insulation to the entire building envelope, changing to low energy windows, installing balanced ventilation with heat recovery and implementing individual metering and invoicing of domestic hot water.

According to the owner of the building the energy saving measures are not profitable for this pilot project. The owners requirement on return on capital is 6.25%. A discussion is ongoing as to changing the evaluation of energy saving measures and lowering the requirement on return on capital to 5%. The owners have continued with similar renovations with similar energy saving measures in five identical tower blocks in the same area. The renovation now also include adding two floors with new apartments on top of the roof. This way the owners requirement on return on capital is fulfilled.

However, a LCC calculation according to the guidelines of IEA Annex 56 result in good profitability for the pilot project. The difference is a lower interest calculated for costing purposes and a longer lifetime, which could be motivated from a societal perspective.

A life cycle analysis from “cradle to grave” showed a reduction of greenhouse gas emissions for the pilot project. A corresponding analysis of the use of primary energy showed a very small improvement. A better choice of materials used for the energy savings measures resulted in a reduction of primary energy. The main aim of the energy saving measures was to reduce the purchased energy and thereby the yearly energy costs i.e. during planning no life cycle analysis was carried out.

13:50
Retrofit of multi-family homes with central heat recovery ventilation, learnings from three case studies
SPEAKER: Fabien Coydon

ABSTRACT. This paper addresses the implementation of ventilation systems within the context of energy retrofit of residential buildings. Indoor air quality is a parameter of crucial importance when the airtightness of the building envelope is increased. A mechanical ventilation system is required and may strongly influence the energy demand of the building and the user comfort. Three German multifamily homes have undergone deep energy retrofits and have been equipped with central ventilation systems with heat recovery. An analysis of their implementation and of the results provided by a long-time monitoring is proposed. As the monitoring concept of the largest of the three buildings, a high rise building with 144 dwellings, is more detailed, a specific focus is set on this building especially regarding thermal comfort and user behaviour. Through a comparison between different ways to determine heat recovery efficiencies, it can be shown that the position and the insulation level of the ventilation device and of the ductwork as well as the electricity demand of the fans play a key role regarding the energy performance of the whole system. A definition of the heat recovery efficiency taking the electricity demand and primary energy coefficients into account is proposed and implemented to evaluate the performance of the three analysed ventilation systems. The importance of the balance between exhaust and supply airflows is underlined. Other parameters, like the control strategy of summer bypass and frost protection are also investigated. For one of the three buildings, a similar neighbour building has been retrofitted with a standard central exhaust ventilation system without heat recovery. This enables an interesting comparison between both systems and shows that in this case, the global primary energy consumption of heat recovery ventilation (16.9 kWh/m².a) remains lower as for exhaust ventilation (22.5 kWh/m².a). The influence of the ventilation system on the thermal comfort is evaluated through measurements of the supply air temperature. For the high rise building, the user behaviour is investigated through inside temperatures, window openings and individual heat consumptions. A wide disparity of behaviours is observed and shows that the temperature differences between neighbour dwellings have a stronger influence on the energy consumption as the window opening rates. It can be concluded that the implementation of central heat recovery ventilation systems in the energy retrofit of residential buildings provides a high thermal comfort as well as good energy performances despite the differences between these performances and the ones expected during the planning phase and despite the difficulties to operate these systems correctly. As the market share of decentralised heat recovery ventilation increased rapidly during the last decade, similar investigations have now to be performed with decentralised systems and an objective comparison between both technologies has to be drawn.

14:00
Different ventilation strategy implementation for achieving nZEB standard of school building

ABSTRACT. Implementation of nZEB (nearly zero energy building) standard for public buildings will be an essential requirements of EU in near future. It is going to be especially important in school buildings as promoting energy efficiency for wide range of people. In the other hands improving energy standard of schools may often be connected with decreasing of indoor environment conditions. In these context it is crucial during the renovation of school building to improve both indoor climate and energy standards. Complex modernization of public buildings is a subject of a KODnZEB project co-financed by Norwegian founds. One of the work done within a project was preparing energy efficiency ventilation concepts for classroom with special attention paid for both indoor climate and nZEB requirements. The paper presents results of renovation an typical school classroom with different ventilation strategy. One is mechanical balanced ventilation with heat recovery and the second is natural/hybrid concept of ventilation. For both cases of ventilation model of energy performance as well as calculation of indoor climate were analysed. In this study, the 6R1C model with air handling unit (AHU) component developed at Warsaw University of Technology was used for simulation of energy performance. The model is a modification of simple hourly method described in EN ISO 13790:2007. The most important modification is related to splitting air flows between outdoor and indoor into controlled airflow and uncontrolled infiltration/exfiltration. Model of indoor climate is based on regression technics and results of measurements (indoor temperature, relative humidity, and CO2 concentration) performed in real schools. These way of calculations can include both controlled air flows caused by ventilation/infiltration and air change rate caused by stochastic in nature windows opening. It has been showed that providing thermal comfort condition is rather not problematic, but energy performance and indoor air quality can vary a lot between different ventilation strategies. As a results the primary energy (heating energy and electricity used for ventilation) and ventilation rate (indicated as CO2 concentration) were analyzed and commented. It has been showed that in middle Europe (Poland) it is possible to meet nZEB standards together with proper indoor air quality by both balanced mechanical ventilation with heat recovery and natural/hybrid ventilation.

14:10
Energy reduction in public building stock: assessing the impact of control strategy over expected energy savings and indoor comfort level

ABSTRACT. In the framework of EU FP7 BRICKER project, the renovation of public owned non-residential buildings is addressed through the installation of innovative passive and active technologies. The expected impact is a primary energy reduction of about 50% with respect to the existing scenario with a large replication potential under different European countries. In order to achieve such ambitious goal one issue that cannot be ignored is the effect of control strategy, not only over the resulting energy performance but also over the resulting indoor comfort conditions. In this paper, the actual control strategy implemented in the Belgian demo of Bricker project is introduced, compared against an ideal approach and accordingly optimized. The resulting proposed approach is then tested by means of numerical simulations over a base case scenario before renovation. The main conclusion of this work is the demonstration that control strategy of energy generation and distribution systems has to be revised whenever deep renovation of passive or active building technologies is undertaken. Contrarily to which, project renovation goals cannot be met.

14:20
Actual energy savings of thermal renovation in the dwelling stock: the results of a large scale study in the Netherlands
SPEAKER: Laure Itard

ABSTRACT. The assessment of actual energy savings resulting from thermal renovation of dwellings was up to now limited by the high costs of such a monitoring operation. That is why only assessments at project level are found in (scientific) literature. The emergence of large databases at national level, however, makse the assessment at the level of the whole building stock possible, producing very valuable results for policy makers and the building sector. This paper presents the results of a large scale study in the Netherlands, where a national energy label database of the association of social housing associations, containing yearly updated data about 2 million dwellings, was coupled at address level to the actual energy database from Statistics Netherlands. In this database, actual gas en electricity use of each Dutch dwelling is registered yearly. It has been possible to select out of these databases the dwellings that had undergone a thermal renovation between 2011 and 2013 and to compare their heating energy consumption before and after renovation. The size of the database made it possible to isolate dwellings in which only one renovation measure was taken, giving the possibility to describe statistically the effect of taking such a renovation measure and to assess its efficiency. For instance in more than 30.000 dwellings heating system, and only the heating system, was replaced. In almost 16.000 dwellings old glazing –and only the glazing- was replaced by a more efficient one, and in more than 21.000 dwellings the envelope has been insulated, while no other measures were taken. The energy savings in these dwellings were analyzed and compare to the expected savings before renovation, showing in general much lower savings than expected. Improvements in efficiency of gas boilers (heat and hot tap water) yield the biggest energy reduction, followed by deep improvements of window quality. Next to actual average savings for each type of measure, the research also shows that the energy consumption relating to efficient heating systems, high efficiency glazing and good envelope insulation is well predicted, while this prediction is very poor in low efficiency heating systems, single glass and poorly insulated houses. In these cases the actual energy use is much lower than predicted. This is a main reason for not achieving predicted energy savings after a thermal renovation.

14:30
Actual Energy Savings of Renovated Dwellings꞉ the case of Amsterdam

ABSTRACT. The existing housing stock plays a major role in the realization of the energy efficiency targets. The non-profit housing sector in the Netherlands dominates the housing market as it represents 31% of the total housing stock. In the municipality of Amsterdam, where this share is even 46%, subsidies were given to housing associations between 2011 and 2014 when an energy renovation of their rental property took place and resulted in a better energy performance. The aim of this paper is to examine the impact of thermal renovation on the actual and the predicted energy consumption of the dwellings concerned and to compare both types of consumption. For the non-profit rental dwellings that have undergone renovation in Amsterdam, we use longitudinal data from 2009 to 2013 to examine their actual and predicted gas consumption before and after renovation. The main outcome of the analysis is that in almost all groups of dwellings the gas consumed after renovation decreased significantly. Most of the dwellings had a combination of measures performed and the actual gas consumption savings depend on these combinations. Despite the fact that gas savings after renovation were observed in all dwellings no pattern was found indicating that the better the predicted energy performance achieved, the more actual savings were realized after renovation, but this may be due to the relatively small size of the sample.

14:40
Energy efficiency renovations in residential building: What are the key variables in the decision-making? Evidence from France
SPEAKER: Anna Risch

ABSTRACT. The building sector is the most important energy consumer in many developed countries. With regards to European countries, the European Commission states, in the 2011 Energy Efficiency Plan, that the greatest energy-saving potential lies in buildings. This is due to the improvements in efficiency of insulation or appliances. However, literature shows that households do not invest significantly in energy-saving measures even if it is profitable in the long run (Brown, 2001; Sanstad et al., 1995; Van Soest and Bulte, 2001). This is mainly because of market imperfection (i.e. uncertainty about energy prices or energy savings following a renovation and the irreversibility of the investment). To induce households to undertake energy-saving renovations it seems important to understand the key variables in the decision-making. In this paper, we analyse the decision to undertake energy-efficiency renovations. This is the first step of a multidisciplinary project, including researchers in economics and engineering sciences. An econometric analysis is used to underline the incentives and obstacles to undertake energy-efficiency renovations. We choose to study the renovation expenditures with a French dataset, which provides information on the energy-saving renovations undertaken over five years. We observed expenditures only for households which undertake a renovation (and we do not know how much households that have not renovated would have spent if they had undertaken a renovation). This leads to a censorship problem. To take it into account, we use a tobit model. Our objective is to understand the key variables that impact on the decision to renovate, including the effect of public policies, of dwellings and of household characteristics. In terms of household characteristics, being an owner with a high income significantly increases the renovation expenditure. Dwelling characteristics are also important (such as the year of construction and the type of dwelling: house or apartment building). We show that being informed of the existence of a tax credit has a significant and positive effect on renovation expenditures, ceteris paribus. Conversely, policy having an informative role has no effect. Through public policies, the objective of the government is to significantly decrease the energy consumption of the residential sector. However, literature underlines the presence of a rebound effect and shows that by following an energy-saving investment, households may prefer to increase its comfort, through an increase of dwelling temperature for example (Groening et al., 2000). Our results show that, besides energy-savings, the increase in comfort also appears as an important variable. This can at least partially offset the beneficial effects of the renovation. The results obtained will be used to build a decision-making tool in order to rank the best options in terms of renovation. The objective is to help the owner to take the decision to renovate his house. This tool will be designed using the MACBETH approach (Measuring Attractiveness by a Categorical Based Evaluation Technique) (Bana e Costa et al., 2012), which is a multicriteria decision analysis approach and allows to rank the options.

13:30-15:00 Session SS 20: Ventilation & Air Distribution
Location: Radiosalen
13:30
An experimental and simulation study of night cooling in a building with hybrid ventilation

ABSTRACT. The cooling energy demand in a building can be reduced through night ventilation coupled with interior thermal mass. A 17-storey high building at Concordia University in Montreal, Canada was designed with a hybrid ventilation system and is used as a case study in this paper. This study is part of a research project aimed at developing simplified models of the building thermal response that can be used for model predictive control (MPC). Cool outdoor air enters the building through motorized inlets at opposite ends of corridors, heads towards the virtual solar chimney consisting of 5 interconnected stacked atria, while extracting heat from the thermally massive concrete floor. By pre-cooling the building at night under hybrid ventilation, the cooling load for the next day is reduced. This paper focuses on the modeling of a region of a typical corridor near an inlet to estimate the heat removal rate from the floor and to establish at what minimum inlet temperature night ventilation can be operated without adversely affecting comfort.

A two-dimensional explicit finite difference thermal model is developed to simulate the air and floor surface temperatures. On-site measurement data were acquired to validate the thermal model and to establish boundary conditions and practical thermal mass cooling rates in a computational fluids dynamics model is also created in FLUENT to visualize the air’s flow path and velocity.

The rate of heat extraction for the 10 m length of corridor reaches 26.9 W/m2 in the first hour and drops to 24 W/m2 for the 4 h experiment. Extending the duration of night ventilation will further decrease upcoming cooling loads; however, the limiting factor is then how low of an inlet temperature is allowed without compromising occupant comfort. Since the corridor is a transition space, flexibility in the occupants’ perception of thermal comfort is expected, and the maximum predicted percentage of people dissatisfied may potentially be increased to 40 % [1]. For this case, the conditions near the end of the corridor is considered since occupants do not frequent the space near the inlets. The draft rate, representing the percentage of people predicted to be dissatisfied due to draft, is expected to be close to, but not exceeding 40 %, assuming a turbulence intensity of 1-5 % and an air speed of 0.5 m/s. In terms of air temperature, the measured data stays within the limits of acceptable vertical air temperature difference. Although the experimental data shows that the air has an asymptotic value of 13.5 °C, the temperature rises to 19 °C within one hour after the inlets are closed.

Hybrid ventilation can allow cool outdoor air as low as 11°C into the building during unoccupied hours, and raise the limit shortly before occupied hours in order to maximize free cooling. An accurate and simple building thermal model can be used to calculate the cooling energy demand reductions in anticipation to warmer upcoming days, while maintaining occupant thermal comfort, as well as for real time MPC through a building automation system that controls the motorized inlets and the variable speed fans at the top of the atria.

13:40
Hybrid ventilation control strategies to reduce energy consumption in a small office building
SPEAKER: Hojong Hwang

ABSTRACT. Weather condition is greatly influencing energy consumption of HVAC system. This paper investigates hybrid ventilation to develop control strategies to optimize HVAC system operation in summer season. The control strategy is combining natural ventilation and mechanical system to cool the occupied indoor spaces. The fraction of window opening is determined based on outdoor temperature when natural ventilation is applied. Mechanical ventilation works in case if airflow rate of natural ventilation is insufficient. A small office building is simulated using Energy plus with energy management system (EMS) feature based on Seoul weather data for one week of the summer period. The investigation includes comparison of energy consumption between conventional HVAC system and hybrid ventilation system. The result shows that the hybrid ventilation system able to reduce around 25-36% of a conventional HVAC system.

13:50
A field study on the thermal comfort performance of a ventilative cooling system in a retrofitted low energy building

ABSTRACT. Ensuring optimal thermal comfort performance in low energy building retrofits during the shoulder and summer months is challenging. One of the reasons for this is overheating due to internal and solar heat gains. The prompt removal of this trapped heat, using natural ventilation only, is critical to ensuring adequate levels of thermal comfort in free running buildings. This study investigated and evaluated the thermal comfort performance of a retrofitted ventilation system in a low energy building. A control space (a seminar room) was preheated in order to simulate an overheating scenario in shoulder season conditions. Four ventilation configurations were investigated with one control configuration (no ventilation). The thermal comfort performance of each configuration was evaluated subjectively using two standardised questionnaires based on ISO10551. Thermal comfort was also analysed objectively through the calculation of a variety of thermal comfort indices. The results of each configuration were categorised using ISO7730, where the actual and predicted thermal comfort were compared. Results showed that the Predicted Mean Vote model over-estimated neutral thermal sensation votes by over 86% throughout the study, while failing to register any thermal votes outside of ±1. The calculated neutral temperature for participants in the study was seen to be 24.7°C. Overall the results showed that there was varying thermal comfort performance for two configurations of the same area but with different opening heights. Subjectively the best category of comfort from ISO 7730 was not achieved for any ventilation configuration during the study, with the highest category achieved being category B.

14:00
Experimental Assessment of Mechanical Night Ventilation on Inner Wall Surfaces
SPEAKER: Wenhui Ji

ABSTRACT. The cooling potential of night ventilation largely depends on the heat exchange at the internal room surfaces. During night time, increased heat transfer on a vertical cooled wall is expected due to supply air that flows along the internal wall surface from the top of the wall. This paper presents an experimental study of the mechanical night-time ventilation on cooled wall surfaces in a test room. Significant improvement of indoor thermal environment is presented resulting from the enhanced internal convection heat transfer.

14:10
Ventilative Cooling Potential in Low-Energy Dwellings – The HoTT Case Study

ABSTRACT. INTRODUCTION: Research indicates that low-energy dwellings are more sensitive to overheating than regular dwellings. Ventilative cooling is an interesting technique to mitigate potential overheating in such cases and avoid the introduction and/or use of active cooling systems to compensate for that. Therefore, in this research, the ventilative cooling potential of low-energy dwellings is considered. A low-energy dwelling, based on the Active House concept, “House of Tomorrow Today” (HoTT) has been investigated as representative for low-energy dwellings in general. This study wants to answer the research question to what extent overheating is expected and can be prevented in HoTT and how quickly HoTT can be cooled down through application of the ventilative cooling principle. METHOD: A computational model of the house was created with the software TRNSYS (in combination with CONTAM) and this model has been calibrated with actual (intervention) measurements in the HoTT. Next, with the calibrated model, the potential of creating or maintaining thermal comfort in the house by applying ventilative cooling has been considered, either through different settings or in combination with design parameters such as opening area, shading and addition of thermal mass. As performance indicator the neutral temperature as function of the reference outdoor temperature is considered. RESULTS: The simulation results show that ventilative cooling in combination with other design requirements (sun shading and thermal mass) is able to significantly reduce the overheating potential for the HoTT for current typical summer climate conditions and provide with that a more robust solution for future climate developments with less need for active cooling. Lack of inclusion of these design principles will affect the indoor conditions significantly. As HoTT applies a relative lightweight construction the advantage of thermal mass is less well exploited. However, in an overheating situation, the potential of ventilative cooling in the current HoTT-design can be increased even more, i.e. higher air change rates can be obtained, by increasing the currently fixed limited atrium window opening areas. CONCLUSION: The results confirm that overheating is an issue of concern in a low energy dwelling such as HoTT if no remediation actions are taken (either active or passive). The need for a combined application of measures reflects that overheating mitigation is an integral design problem. For the Dutch climate the potential of ventilative cooling in such a case is obvious and could be exploited better for the HoTT.

14:20
CONTROL STRATEGIES FOR VENTILATIVE COOLING OF OVERHEATED HOUSES.

ABSTRACT. During the 1960s and 1970s approximately 440,000 single family dwellings were built in Denmark. Buildings constructed before 1979 are responsible for 75% of the total energy consumption of this sector. The total stock amount have to be renovated by 2050. The coming decades should see deeper or nearly zero energy renovations if the full economic and social potential are to be realized. However, many post-occupancy comfort studies document elevated temperatures not only during the summer period but also during the transition months. Evidence shows that high indoor temperatures cause serious impacts to the indoor quality and result in seasonal increase of morbidity. Ventilative cooling can be an attractive and energy-efficient passive solution to avoid overheating in renovated residences. For home owners, cooling is an unknown challenge that they have not experienced before and their behavior might instead increase the problem. The aim of the research is to highlight the problem of overheating in energy renovated single-family buildings in Denmark and to investigate the ability of a representative manual window use and different automated window control strategies in order to eliminate overheating risk under different opening positions, wind conditions and discharge coefficients (parametric analysis). The study will also include examination of the ability of a mechanical ventilation system and shading systems regarding the overheating occurrence. The objectives been fulfilled through the simulation and analysis of a real representative single-family house from the 1970s as extracted from TABULA project. The case study is retrofitted deeply and high efficiently (nZEB) creating two different renovation scenarios. The overheating is assessed by the “percentage outside the range” method of EN 15251:2007 standard (yearly assessment). Manual control and mechanical ventilation system for both renovation scenarios and all the used natural ventilation parametric values cannot sufficiently eliminate the overheating risk indoors (8.7% and 7.8% overheating occurrences respectively). The use of different external shading systems significantly decreases the overheating occurrences for both strategies and renovation scenarios (more than 70%). The increase of the discharge coefficient, the presence of the wind and the increase of the window opening position significantly decrease the overheating occurrences for both scenarios and all the control strategies. The automated control of the windows eliminates the overheating problem for both renovation scenarios. The fully automated control strategy (control during the whole day) presents the best performance among the three strategies of the automated control (parallel use, automated during the occupied period and fully automated). In all the cases of the parametric analysis of the automated control strategies, the nZEB renovation scenario presents lower values of overheating occurrence compared to the deep renovation scenario.

14:30
Performance in practice of a ventilation system with thermal storage in a computer seminar room
SPEAKER: Thiago Santos

ABSTRACT. Computer classrooms present challenges for cooling because internal heat gains higher than typical classrooms. Focused on thermal comfort, this paper presents the results of a field and computational study of a computer seminar room in west England. A mechanical ventilation system with phase change materials thermal storage has been installed in the room to provide thermal comfort and indoor air quality. Monitored data of internal air temperature, CO2 and humidity were analysed and compared with current requirements for indoor air quality and comfort. The analysis indicates that good internal environmental conditions are provided by the system. To better understand the ventilative cooling performance of the system a week in early September was chosen and analysed in detail. In addition the hottest hour of the week was chosen for further analysis using CFD using air temperature monitored data for calibration. Results show that even for the most extreme external conditions of the monitored period, the seminar room has a uniform temperature distribution within thermal comfort requirements and air velocity ranging between 0.11 to 0.17 m/s close to the students and will not cause uncomfortable draughts.

14:40
International Ventilation Cooling Application Database

ABSTRACT. Introduction: The currently running IEA, ECB, Annex 62 Ventilative Cooling (VC), is coordinating research towards extended use of VC.Within Annex 62 Subtask B (Solutions) the joint research activity of International VC Application Database has been carried out, systematically investigating the distribution of technologies and strategies within buildings using VC.

Methodology: The database is structured as both a ticking-list-like building-spreadsheet and a collection of building-datasheets. The content of both closely follows the Annex 62 State-Of-The-Art-Report chapter 5, written by the main-author. The database has been filled by Annex 62 participants, namely by the authors, based on desktop research. The database has been used for basic correlation analyses, highlighting the frequency of specific VC technologies and control strategies, correlated with usage, size, location and else.

Results and Discussion: So far the VC database contains 91 buildings, located in DK, IE, AT. Further contributions from other countries are expected. The building-datasheets offer illustrative descriptions of buildings of different usages, sizes and locations, using VC as a mean of indoor comfort improvement. The building-spreadsheet highlights distributions of technologies and strategies, such as the following. (Numbers in % refer to the sample of the database’s 91 buildings.)

1. Building Use is dominantly office 55%), educational (215) and others (22). Only 8% residential. 2. Location is dominantly urban (60%) 3. Ventilative Cooling Site Design Elements are applied in 65%, equally distributed between Solar Site Design, Wind Exposure Design and Evaporative Effects. 3. Ventilative Cooling Architectural Design Elements are applied in 95%, dominantly by Morphology, Envelope and Construction (66% to 78%), less by Form (49%). 4. Airflow Guiding Ventilation Components are used in 99% , dominantly by Windows, Rooflights, Doors (96%), more seldom by Dampers, Flaps, Louvres (44%) or by Special Effect Vents (5%). 5. Airflow Enhancing Ventilation Components are applied in 66%, dominated by atria (63%), chimneys (16%) and very rare cases of others. 6. Passive Cooling Components are used in 26%, dominantly by Convective Cooling Components (22%), with only very rare cases of others. 7. Actuators are identified in 66%, dominated by chain actuators (57%), followed by Linear Actuators (9%). 8. Sensors are identified in 88%, including Temperature, Humidity, CO2, wind, rain and solar radiation 9. Control Strategy is reported as hybrid in 58%, as automatic in 29%, as manual only in 4%.

Conclusion: Ventilative Cooling is applied in temporary European and international Low Energy buildings. Still it’s not really widespread. Obstacles are challenges as regards noise, dust, weather and burglary, proving the research efforts of the Annex being necessary. The VC database forms a worthwhile basis for both dissemination and further research targets.

Acknowledgements: The research offered for presentation has been financially founded by Austrian Ministry for Transport, Innovation and Technology within the IEA-research-cooperation.

14:50
Exposure reduction to human bio-effluents using seat-integrated localized ventilation in quiescent indoor environment

ABSTRACT. Local airflows generated from people such as the natural convection flow may determine the distribution of pollutants indoors. New seat-integrated ventilated method was developed to improve the inhaled air quality of occupants while seated. The method named “Ventilated Seat” was designed to suck gaseous pollutants (i.e. bio-effluents) emitted from the body of a sedentary person and exhaust them before they entrained in the person’s breathing zone or mix with the surrounding air. Full-scale experiments were performed in a climate chamber with dimensions 4.7 m x 5.8 m x 2.5 m (W x L x H). The chamber was ventilated by an upward piston flow through the floor. The construction of the test room ensured conditions with uniform temperature field and air velocity lower than 0.05 m/s i.e. quiescent environment. A sitting person was simulated using a dressed thermal manikin which had a body shape and surface temperature distribution of a real average person under thermal comfort. The chair on which the thermal manikin was sitting was equipped with the ventilated seat (VS). The interaction between the natural convection flow around the human body and the suction from the ventilated seat was studied in terms of transport of gaseous pollutants. The ventilated seat was tested at three exhaust airflow rates through the seat - 1.5, 3 and 5 L/s. During the experiments tracer gases were used, CO2 and N2O, to simulate human bio-effluents generated from armpits and groins of the manikin respectively. The experiments were conducted at 20°C and 26°C room air temperature. The performance of the ventilated seat was assessed by measuring the pollution concentration in the breathing zone of the manikin and at 0.5 m above the head of the manikin. The measured concentration while the VS was in operation was compared with that obtained when the VS was not working. The results showed that the concentration of the pollutants decreased when the VS was in operation during all carried measurements. The higher the exhaust flow rate of the VS, the more the concentrations decreased at all of the measured conditions and at all of the measured locations. The results from this study showed that the use of the VS provides an efficient method for control of the body-emitted gaseous pollutants in order to improve the inhaled air and indoor air quality in general utilizing small amounts of air.

13:30-15:00 Session SS 26: Building Performance
Location: Hal Øst
13:30
REFERENCE BUILDING ESTABLISHMENT PROCEDURE FOR THE RESIDENTIAL BUILDINGS IN TURKEY

ABSTRACT. The European Directive on the Energy Performance of Buildings (EPBD Recast, Directive 2010/31/EU), introduced the “cost optimality” concept in order to take also economic effects into account while analyzing the energy performances of the buildings with different measures. The cost optimal methodology framework provided by the European Commission involves several stages starting with the establishment of the reference buildings representing the building stock. This stage is important since all of the following analyzes are applied on these reference buildings with the aim of achieving generalized solutions. A research project supported by the Scientific and Technological Research Council of Turkey was conducted in order to define the procedure of reference building establishment and adapting the cost optimal methodology in Turkey. This paper displays the reference building definition procedure followed in the research project. The study involves statistical data collection, review of the national and international standards, meetings with the experts and examination of the real buildings. Istanbul is selected as a pilot city for this study since this city contains various building types and user profiles. The residential buildings constructed in year 1985 and later were considered for the research. Twenty six reference buildings were defined in three categories: single family houses, apartment buildings and luxury high-rise residences. These buildings represent the building stock in Istanbul but the procedure can be applied for other regions in Turkey as well. The reference buildings and their properties are also presented in this paper in detail. The research shows that there is some data about the physical properties of the building stock in Turkey. However, there is very little information about the thermo-physical properties, user profiles and HVAC systems which are needed to calculate energy performances of the buildings. The existing building stock needs to be deeply analyzed by the authorities considering the energy performance related measures and the reference buildings are required to be defined also for other regions of Turkey by following a similar procedure.

13:40
Relevance of renewable energy ratio in describing nearly zero energy buildings

ABSTRACT. The energy used in nearly zero-energy buildings has to be covered to a significant extent by energy from renewable sources by the EPBD directive definition and renewable energy ratio can be used to quantify the proportion of renewable energy. It has been discussed should the Member States set requirement for minimum renewable energy ratio or would it be adequately covered by the non-renewable primary energy indicator. The purpose of this study was to assess, if setting requirements of the renewable energy ratio of nearly zero-energy buildings is relevant. We studied the energy use of 8 nearly zero-energy buildings in Europe, calculated the primary energy and renewable energy uses and analyzed grid loads of the 4 buildings that had hourly energy use data available. The primary energy uses and renewable energy ratios of the buildings varied between -1 and 96 kWh/m2 and 106% and 28% respectively, whereas there was a good negative correlation. Renewable energy ratio was not particularly sensitive to the use of total and renewable or non-renewable primary energy factor or calculations without factors. Renewable energy ratio did not allow drawing conclusion about the grid load and hourly data about energy use was required to assess grid loads. This allowed concluding that renewable energy ratio did not provide useful additional information and it would be more straightforward and transparent to operate with non-renewable primary indicator only.

13:50
Near zero, zero and plus energy buildings: revised definitions

ABSTRACT. Nevertheless the discussion on nearly Zero, net Zero, Zero energy building is going on since the EPND recast has introduced its nZEB definition, it not today clear to anyone the differences among them. Moreover the introduction of the plus energy building may increase such confusion arising from the misuse of “primary energy” term without any attribute (non-renewable, renewable, total).

Here a survey of current definitions is the starting point to underline inconsistencies and critical issues, and to identify weak points. From these, distinguishing between energy and primary energy, with all its attributes, and between energy sources and energy carriers, a proposal of revised definitions of near zero, zero and plus energy buildings is formulated. This analysis is based on the use of the classic energy balance, but taking into consideration that a building is always a net energy consumer (it always produce entropy or destroy exergy). Special attention is then paid in clearly defining primary energy factors for energy carriers produced from renewable energy sources on site, nearby or far. Although the primary energy factors values have been fixed sometime by political reasons, a clear scientific definition is limiting them to a reasonable range these values, which at least do not violate the basic principles of thermodynamics.

Finally, to clarify that a “plus” building cannot create energy but can just contribute to the local or regional electrical energy production by feeding the grid, a complementary energy index is then proposed beyond than required by the EPBD. This can overcome the questioning on the “negative” primary energy index that can be achieved by such building using some of current net ZEB definitions(1). In this way is possible to spit the main function (and its quality) of a building from the secondary function (and quality) of being a distributed electric generator for the grid without losing any values and complying with the nearly Zero Energy Building definition of EPBD.

This proposal would be a rationale support to the ongoing effort of harmonizing technical items related to buildings energy performances, inside and outside Europe, hopefully without losing scientific consistency.

14:00
BUILDING – ENERGY – EFFICIENCY – CONFUSION – MISCONCEPTION – REALITY
SPEAKER: Mile Siljak

ABSTRACT. In recent years, the deontological synergism has recruited many researchers in the field of exploration of the interaction of integral construction facility at all stages of its life cycle, and the surround environment. In designated area, there is a continuing observation of particular singular linguistic, technical and scientific uncertainties, false understandings and interpretations. This knowledge inspired the subject research in order to eliminate perceived, whereby resorted unusual draft research, which was the plan, structure and strategy helped finding answers to a set of selected research questions noetically recognized, holistically formulated and logically systematized: What makes integrated building structure at the level of partial functional units; Can it be built and used as a dedicated integrated building structure without compromising the environment; What can only and only be the subject of observations on the basis of energy efficiency in integrated building structure; in what correlation are integral building structure and thermotechnics; What is a function of sophisticated objective function of termotechnical systems represented in the integral building structure; What correlation do integral building structure and energy and efficiency make; Can the energy efficiency of the building be determined as a partial functional mid integral construction of the facility; Can a part of the building as a partial functional unit of an integrated construction facility contribute to energy efficiency and other partial functional units contained in the integrated building structure; Is there an integral construction facility "zero energy" and "zero plus energy"; What are the forms of interaction of integrated building for all stages of its life cycle with its surrounding environment; Is energy being "consumed" or "used"; Are guidelines properly formulated: "thermal energy", "energy performance of the building structure", "building physics", “architectural physics” and "Energy efficiency of buildings." Using the method of causal-conclusion analysis with inductive concluding, the answers were obtained which eliminated doubts and false understandings and interpretations, and the same are also of axiomatic nature leaving no space given opportunities to be bypassed in engineering practice, profession and science. The present work aims to contribute to proper and efficient communication and objective investigation of subject matter, and thus contribute to environmental protection and sustainability of Planet Earth.

14:10
Revisiting Business Models within Cloud Market
SPEAKER: Lara Lopez

ABSTRACT. ASCETiC supports software developers to optimise energy efficiency from designing, developing, deploying, and running software in a cloud. In particular, it relates software design and energy use, depending on the deployment conditions and the correct operation of the service by means of an adaptive environment. In this context, we focus on the existing business models within the cloud market, and investigate how they could be evolved taking into account energy efficiency considerations. The three main actors identified, basically SaaS, PaaS and IaaS providers, are those that can adopt ASCETiC results, and can extend their current business models based on these premises. Based on this, we propose and implement a methodology for validating business models according to different considerations in order to determine which the most promising ones within the cloud market are.

14:20
Building energy performance rating: impact of the reference characteristics in the notional building approach
SPEAKER: Wolf Bracke

ABSTRACT. Introduction During a research project commissioned by the Flemish government in Belgium, several methods were studied regarding the normalization of building energy use in order to update the current domestic building energy regulations. Much attention was paid to ensure that dwellings of a different typology (apartments, detached houses …) and size were judged by the normalization method in a fair way. Methods Rather than using a small sample of fictive houses to study the impact of the proposed normalization methods, 6.000 houses of 6 different typologies were randomly selected from a database of the Flemish Energy Agency, where all the characteristics (dimensions, building envelope and HVAC systems) of recently constructed houses are collected. Among others, the notional building approach was studied as a normalization method. In this approach, the energy use of a house gets compared to the energy use of a reference house with exactly the same dimensions, but with predefined characteristics of the building envelope and HVAC systems. Results At first sight, the notional building approach seems like a fair normalization method: when a house is designed larger or smaller, the reference house also gets larger or smaller, thus resulting in the same building energy rating. Further analysis revealed that the building energy rating of different houses (typology and size) is very much depending on the characteristic of the building envelope and HVAC systems, both in the designed building and in the notional building. As a result, it’s very hard to define the reference characteristics of the notional building without favoring a certain type of houses. The explanation can be found in the building energy calculation method, where some parts of the overall energy use are calculated based on the building envelope area (e.g. transmission losses, air infiltration losses …) and others are based on the volume of the building (e.g. ventilation losses, internal gains …). As houses of a different typology and size, have a different ratio between the volume and the building envelope (= compactness), the impact of the performance (design compared to reference characteristics) between envelope area-based and volume-based parts of the building energy use is of great significance. Discussion The ‘average building approach’ is proposed as an alternative to the notional building method. In this normalization, the energy use of a building is compared to the energy use of a reference building with the same volume, but not with the same envelope area. The envelope area is calculated as an average area corresponding to the volume of the house, based on energy performance database. As a result of the fixed ratio between volume and envelope area, the impact of the reference characteristics (both building envelope and HVAC systems) is of much lesser importance.

14:30
Life-Cycle Cost-Optimized Cooling Systems for European Office Buildings
SPEAKER: Saqib Javed

ABSTRACT. This study compares the life-cycle costs of various conventional and emerging cooling systems in representative European climates and energy markets. Firstly, cooling demands and energy requirements of a multi-story office building are determined in compliance with local building codes in six different European locations. Life-cycle costs of various cooling systems are then calculated using location-specific market prices and economic data. The results indicate that no single cooling system is an optimal choice for all locations. In cold climates, conventional vapor compression systems are shown to have the lowest life-cycle costs. In moderate and warm climates, solar electricity driven vapor compression systems have the lowest life-cycle costs. Absorption and solar thermal cooling systems are shown to be economically infeasible under current market conditions.

14:40
Classifying Office Plug Load Appliance Events in the context of NILM using Time-series Data Mining

ABSTRACT. INTRODUCTION Smart building energy management requires knowledge of individual appliance operations. Traditional energy auditing approaches require metering every single appliance in the building. This can be intrusive and not scalable in time and cost across large buildings. On the other hand, the data driven approaches to auditing energy use in buildings is becoming prevalent. The latter enables predicting the energy breakdown of individual appliances together with their operational state from single-point, aggregate measurement popularly known as Non-Intrusive Load Monitoring (NILM). Several public datasets and disaggregation techniques are available for residential buildings, largely motivated by nationwide smart metering initiatives. Similar datasets for office buildings are not as prevalent. The key purpose of this study is present a classification framework for offices based on custom made office appliance dataset, that can help discover individual appliances and its operational modes from single-point aggregate measurements.

METHODOLOGY This approach to non-intrusive load monitoring is supervised through labeled Office Plug Load Dataset(OPLD) developed at National University of Singapore. The classification approach presented here is based on short episodes (also called subsequences) from time-series data within which appliance events lie hidden. A popular technique for discretizing time-series data known as Symbolic Aggregate approXimation (SAX) lies at the heart of this framework. Mining large time-series dataset, extracting characteristic appliance features and classifying them appropriately based on individual appliance events is facilitated through “Bag of Patterns” based Vector Space Model(VSM).

RESULTS AND DISCUSSION The dataset such as OPLD ideally suits developing context free grammar (CFG) rule repository for appliance characterization and feature extraction. This study focuses on classifying multiple appliance events from three common aggregate appliance use-case scenarios in an office environment. The approach is promising at analyzing subsequence patterns from more than 1700 time-series episodes in the dataset. The results from classifying multi-functional device operations from aggregate signature show errors less than 22% in scenario where three appliances are in operation, whereas error is less than 37% when two appliances are in operation. The results also indicate that the approach is likely to work better as the dataset grows as in the case of big data.

CONCLUSION The aggregate time series measurements in offices pose several challenges in discovering hidden appliance patterns and states. This is one of the first studies to address the challenges in analyzing subsequences from appliances energy signature (data) and their states in the context of office environments. The proposed classification framework shows reasonable promise in identifying individual appliance and their events within aggregate signatures. Besides the approach based on VSM enable visualize subsequences of a time-series using color-coding scheme. Such visualization helps in understanding the relative specificity of an event to others in the time series.

14:50
Thermal Environment of Textile Based Ventilation Combined with Chilled Ceiling

ABSTRACT. Textile duct ventilation combined with chilled ceiling was used to generate non-uniform environment in a double office room. The generated thermal environment was compared with the uniform room environment generated by mixing ventilation (ceiling installed diffusers) combined with chilled ceiling. Thermal manikin and heated dummy were used to simulate occupants performing work at two workstations. Experiments at cooling mode, i.e. summer condition, were performed at two heat loads (occupants, simulated window, PCs and light) - 37 W/m2 and 64 W/m2. Two textile duct designs (along the room length and localized above the workstations) were studied. The results show that the equivalent temperature at the workstation and the operative temperature in the occupied zone of the room decreased in the conditions of the textile duct with the half length of the room above the workstation. Energy can be saved in buildings by reduction of the ventilation rate without compromising occupant’s thermal comfort by non-uniform air-distribution.

13:30-15:00 Session SS 34: Comissioning, Control & Energy Management
Location: Musiksalen
13:30
Utilizing a regression approach for troubleshooting energy performance of Swedish multifamily buildings

ABSTRACT. The follow-up of calculated and actual energy performance for new buildings is important to enable a learning process. Performance verification is however not a trivial task since the traditional energy use intensity indicator (EUI) can display large variations even for buildings with similar design and HVAC systems. Hence, there exists a risk for confusion between building owners and developers when predicted and actual outcome are compared using only this indicator. In this paper, simple methods, based on area normalization and regression analysis are investigated for interpretation of wide discrepancies in measured EUIs within four very similar, newly built multifamily buildings in Umeå, Sweden. It was found that the discrepancies in specific annual energy demand were dependent on the area used for normalization but did not fully explain the variation in the EUIs. The utilization of linear regression for identification and comparison of the buildings heat-loss factor, (ventilation and transmission), and effective solar aperture provided further insights. The regression analysis indicated that the differences in EUIs were due to a combination of chosen area for normalization and solar gain and not the consequence of variations in actual U-values and HVAC systems. Due to the regression methods robustness against influence from the users, it was concluded that the method works well as a complement to the EUI indicator since it provides insights of the buildings thermal performance. This is often of interest to verify for the developer and the property owner since the thermal performance can be controlled in the construction process.

13:40
Reducing the Performance Gap By Design For Commissioning
SPEAKER: Sarah Noye

ABSTRACT. INTRODUCTION It is now widely recognised that incomplete commissioning can be a contributory factor to the infamous performance gap between design promise and actual building energy performance outcome. Some of the problems in the commissioning process can be traced back to thoughtlessness at early design stage. For example the chosen system might be too complicated to be commissioned in the time available or the systems’ layout might prevent any commissioning tasks to start before the structural construction work is completed. In an effort to improve the commissioning of building services, Design For Commissioning (DFC) aims to ensure that design choices are consistent with the practicalities of commissioning.

METHODS The paper describes how the Design For Commissioning process is being developed by a major engineering contractor. This has enabled the identification of key ‘hot spots’ in the commissioning process. Proposals on how they could be improved by special design measures (e.g. measurements’ accessibility, layout design) are presented. As an important part of the commissioning process, time is spent recording measurements. The Design For Commissioning strategy was then reviewed in the light of newly available wireless sensor technology that has been developed to assist ‘soft landing’ post occupancy commissioning. A case study is used as illustration.

RESULTS/DISCUSSION Design for Commissioning is a natural complement to the wider move towards Design for Manufacturing and Assembly. The technique enables the experience of the commissioning engineer to be reflected in design requirements. This includes accessibility for measurements and making settings, consistency with health and safety regulations, and systems’ layout so as to optimise the commissioning planning. An enhanced monitoring capability to facilitate commissioning can be included in the proactive DoC design, but there remains a risk that value engineering will sacrifice the investment in extra sensors etc. since they ‘might not be needed’. Portable wireless sensors circumvent this problem. They need only be deployed as the commissioning merges into a soft landing. They require no wiring, and can be moved on to another site quickly once commissioning is complete. Access is still required, but based on a trial site, in general the design requirements are far less onerous.

CONCLUSION When Design for Commissioning reflects the availability of new monitoring technologies it becomes a powerful step to eliminate the performance gap.

13:50
Automatic Fault Detection Diagnosis and Correction of Energy Monitoring Systems
SPEAKER: Arie Taal

ABSTRACT. This paper describes a method for Fault Detection, Diagnosis and Correction in Energy monitoring systems. These faults may be measurement faults or faults in the hypothesis of the calculation methods and model assumptions. The fault detection process is based on system theory applying analyses of subsystems as well as aggregated systems. Symptoms are estimated by laws of conservation. The diagnosis is based on Bayesian Theory which is applied in a Bayesian Network Method. The result of the diagnosis delivers the probabilities of possible faults associated to the estimated symptoms. Measurement faults can be systematic faults like bias errors or faults by sensors which are stuck. Models and calculation methods are used as well to preprocess data from the Building Management System for energy monitoring as well to set up balance equations for the fault detection process. Finally, the process to correct energy monitoring faults is explained. The described FDDC method is presented in examples.

14:00
RELIABILITY of VENTILATION SYSTEM INSPECTION for DWELLINGS: COMPARISONS of MEASUREMENTS and CONTROLS PROTOCOLS TESTED DURING ON-SITE CAMPAIGN of the PROMEVENT PROJECT

ABSTRACT. The PROMEVENT project, conducted by 8 French organizations, tests and analyzes several protocols for controls and measurements of residential ventilation systems. It aims to make the practices more uniform and to improve ventilation systems inspection protocols, which include visual controls, airflow and pressure measurements at air terminal devices and ductwork airleakage measurement, for both single-family houses and multi-family dwellings. In order to test the reliability of those protocols, various measurements have been performed on 2 multi-family dwellings with humidity demand controlled ventilation systems and 10 single-family houses with balanced ventilation with heat recovery systems. Those tests have been performed by different operators, with different types of measuring devices, on different types of air terminal devices. The analysis of these different measurements points out the weaknesses of the protocols and/or the minimum specifications the instruments should achieve to assure reliable results, in particular for airflow measurement at terminal devices, for which, the type of material used may induce uncertainties due to the technology (not all technologies might be used with all types of terminal) and due to the material it-self (important impact of the correction with calibration data). For ductwork airleakage measurements, important differences of the results have been noticed with different obstructions of the ductwork at terminal devices. Results could also be different between a measurement performed in one time (one section) or in two times (the same section divided in two sections). Therefore, all the tests performed during these campaigns confirm the need for a unique and more reliable protocol.

14:10
Practical approach of an open hybrid Fault Detection and Diagnosis (FDD) method. Application to the HVAC system of a Near–Zero Energy university building.

ABSTRACT. Numerous studies have been carried out to tackle Fault Detection and Diagnosis (FDD) issues in building systems. Various methods ranging from quantitative model based methods to process history based methods have been investigated. Advantages and drawbacks as well as assessments of robustness and effectiveness have been presented. However, for a generalized application of FDD in buildings, studies agree that, besides effectiveness and robustness, FDD methods need to be generic, customizable, easy to implement and suitable for integration into a Building Management System (BMS). Nonetheless, one can note that most of the recent FDD studies focus on improving effectiveness and robustness. This situation relegates the development of a generic method to a lesser priority. Therefore, in order to contribute to a more widespread utilization of FDD, the focus of this research is to implement and test a combination of existing robust FDD approaches by using solely open, proven and well-known concepts, modelling tools and languages. A new workflow for FDD for Air Handling Units (AHU) is proposed, that is easy to implement and to customize. Assuming a successful initial commissioning, this research introduces a generic, hybrid FDD which will be applied to an experimental case and a real-life case study to identify components failure in AHU’s during operation phase. It presents the detailed implementation process and the practical testing of the approach relying on open and proven tools. The method combines physical models for fault detection and statistical machine learning classifiers for fault diagnosis. It benefits from the advantages of the two used methods while the known downsides of physical modeling are addressed by the use of Modelica and functional mockup unit (FMU) features. This is to respectively facilitate model implementation and its use in the BMS. The implementation and automatization of the classification process has been implemented using a proven and dedicated statistical machine learning package written in PYTHON. Additionally an algorithm has been designed to regularly and automatically calibrate the physical model and train the classifiers based on simulated data and new non-faulty monitored data. To assess the effectiveness of the method, it has been first tested on a simulated scenario where faults in the components were introduced. The outcomes showed that the physical model was able to detect the introduced faults and that the classifiers identified the root causes. It has then been integrated into the BMS of a Near Zero Energy university Building to capture any unintended behavior of the real system. This case study emphasizes the efficiency of the physical model in real-time conditions. Further improvement of the classifiers training is currently investigated. An important improvement of this method towards a semi-automatic process is currently developed under the umbrella of the IEA EBC Annex 60. This aims at the generation of a Modelica model of the HVAC system based on topology and data from a suitable, standardized Building Information Model (BIM).

14:20
Air handling unit faults impact on thermal comfort, energy consumption and indoor air quality in an office building

ABSTRACT. INTRODUCTION Widely existing in heating, ventilating, and air conditioning (HVAC) systems, faults always lead to inefficient energy consumption, undesirable indoor air conditions (thermal discomfort and/or poor air quality), and even damage to the mechanical components. Although faults in HVAC systems can lead to disastrous consequences on buildings, this is a topic even little studied in the literature. In this work, the impact of three air handling unit faults is evaluated on the thermal comfort, the energy consumption and the indoor air quality in an office building. The research methodology is based on comparing a reference model of a building with no faults with different fault models. Due to their frequency and repeatability, we have chosen to study the following faults: the offset of the temperature sensor in the building, the leakage of the valve connected to cooling/heating coils, and the air leakage through the ducts. METHODS The office building is located in Trappes, close to Paris (France), and was built in accordance with the French thermal regulation. The reference model, composed of a building model and Air Handling Unit (AHU) model, is implemented in Dymola, using Modelica modeling language and the free open-source Buildings library. Simulations were carried out and analyzed over both summer and winter periods, using the operating conditions for each season. Models for the three different faults were developed and applied to the reference model, in Dymola. The impact of the three AHU faults was studied on the thermal comfort, energy consumption and indoor air quality. RESULTS AND DISCUSSION For the sensor drift fault, six values of offset parameter has been studied (D=-1.5;-1;-0.5;+0.5;+1;+1.5°C). A positive drift decreases the set point temperature and vice versa. Obviously, the energy consumption increases with the offset parameter in summer and decreases with the offset parameter in winter. The performance of the AHU was analyzed for four values of hot/chilled water valve leakage: 1\%, 2\%, 5\% and 10\%. The results show that the valve leakage is a key point of the valve efficiency. It causes serious consequences on the thermal comfort, until -2.6°C in summer and +1.77°C in winter. Furthermore, it increases the energy consumption of the building (2.75 times in summer and 1.25 times in winter). The last model is the duct leakage model, as a function of duct leakage class and position in AHU. Duct leakage has a favorable effect on the indoor air quality, the CO_2 concentration decreases in all cases. During both summer and winter, the indoor temperature decreases with duct leakage. This leads to less energy consumption during summer, and significant increase in heating energy consumption during winter. The effect of duct class is more important than the position of the duct on indoor air conditions and energy consumption. CONCLUSIONS In this paper, the impact of three faults of an AHU was studied on the indoor temperature and energy consumption of an office building using Dymola. The developed fault models and the obtained results show clearly that the effect of the faults can be significant on the operation of the AHU.

14:30
The benchmark analysis of office premises – potential energy saving opportunities in offices with 2nd generation and 3rd generation of energy management systems
SPEAKER: Zoltan Magyar

ABSTRACT. Introduction Buildings are account for 40% of the total energy consumption in the European Union. According to the 2010/31/EU European Union directive the sector including the private sector, commercial and industrial market segments – is continuously expanding which is bound to increase their energy consumption. The European Commission has founded the new vision about the global climate change in Paris, 2015 by collectively reducing the global emission by at least 60% below 2010 levels by 2050. The 2012/27/EU European Directive on energy efficiency fixed that besides the transportation, the production and the process, the buildings are the key figure for finding more energy efficiency potential and reducing the total volume of the energy consumption. Methods and materials In our investigation we focus on the performance peaks and total volume of energy used in the offices premises and defining the potential energy saving potentials. We chose two types of office branches. In the first group we installed 2nd generation of energy management systems with ENERGRADE EMS software to collect, analyse and report the energy consumptions and energy result periodically. In the other type besides the ENERGRADE energy management systems the automation process controllers and automation intervention in the daily energy consumptions has been installed. In our research we use 2nd level and 3rd level energy management software and hardware structure. The 2nd level of energy management system installed for collecting, measuring automatically and periodically (in every 15 minutes) the energy-consumption relating data and reporting the energy consumptions in a semi-automatic way without any process controllers. The 3rd level of energy management system contains the 2nd level of energy management systems’ features and automation programmed controllers. Research locations In our research we focus on representing the key figures and variables effecting on energy performance and energy efficiency in office buildings. In 3 locations in Budapest, Hungary we built up energy consumption data monitoring systems and in 1 location in Budapest, Hungary besides the monitoring system an automated intervention system has been installed. Energy data management system’s goal Our research first goal was to build an energy management benchmark database to represent the difference and similarities in between the office buildings’ energy consumption, secondly to prove the potential energy reduction and energy efficiency gap between the monitored and an automated system and thirdly to examine the correlation between the type of the energy management system and peak performance and fourthly to define and to prioritize the variant parameters effecting on energy efficiency. The research took 6 months long in Budapest, Hungary. Conclusion The benchmark database building (BDB) led us to the followings: in the same running and operational environment the energy volume is different; There are time periods when the energy saving potential is higher than 30%. By use of the 3rd generation energy management systems can add 10% more energy saving potential.

14:40
Bayesian Belief Networks and Expert Systems for supporting model based sensor fault detection analysis of smart building systems.

ABSTRACT. INTRODUCTION Modern smart building systems are equipped with many sensors as information source for the HVAC systems. The combination of data from these sensors can be used for analyzing and detection of faulty sensors. The proposed framework for the sensor fault detection was tested on the building of The Hague University of Applied Science (THUAS) in Delft. This building was selected for the research because this building has a complex HVAC system with an advanced control system and extensive measurement data is available for analyzing the sensor values and the indoor climate. One of us (Taal, TVVL magazine 2015) describes the use of Bayesian method for analyzing the energy consumption in the same building. The building contains mainly classrooms and offices for the lecturers as well as a restaurant. In the rooms of the building cold and heat is delivered by a floor heating system and by ceiling panels in which water is circulated. The ventilation flow rate to the rooms is demand-controlled based on occupancy and the CO2 level. METHODS The sensors used were: CO2, temperature, humidity, occupancy, light, ventilation rate, ventilation valve position, window open/close. The sensor data were input to an Expert system and to a Bayesian system of the building. The Expert System is based on statistical analysis of the data of the building. The results were normalized to a timeslot of an hour, and daily compared with new data with the same timeslot. The BBN system was developed with the help of experts of the HVAC system in the building. (see also Carbonari et all, 2014) RESULTS Both the Expert System and the BBN systems were used to investigate a number of cases of malfunctioning sensor systems in the building by using the historical data. The Expert System was able to find disturbances in several rooms, and could indicate the most plausible cause. The same data were fed to the Bayesian system, and analysis results in early detection of anomalies in the functioning of the HVAC system. DISCUSSION BBN methods are based on rules and expert reviews and also require fine tuning with data, which is often a challenge, the rules for the Expert System are based on the same rules as for the BBN systems, the statistical analysis of the data (the learning of the data) seems to be comparable with the Bayesian system. CONCLUSIONS The Expert system and the BBN system give comparable results with the historic data. The methods described in this article are now being used to analyze and learn from the complete historical [5 years] database.

14:50
Data Filtering and Fault Detection of VAV System using Wavelet Transform and Machine Learning Model
SPEAKER: Young Jin Kim

ABSTRACT. For efficient operation of HVAC systems by Building Energy Management System (BEMS), accurate and automatic filtering of outlying sensor data is crucial. This paper addresses an automating data filtering and fault detection method of a Variable Air Volume (VAV) system. For this purpose, a discrete wavelet transform method and a machine learning simulation model so called Gaussian process model are coupled. To validate the developed model, three fault scenarios (fault offset of temperature and mass flow rate, leaking outdoor air damper, malfunction of coil valve control) were tested. The test was verified using CVRMSE and MBE suggested by ASHRAE. In the paper, it will be concluded that the data filtering and fault detection model provides accurate automatic fault detection for building operators.

13:30-15:00 Session TS 10: High IEQ and energy-efficient ventilation in renovated school buildings (EU IEE Renew-School)
Location: Laugstuen
13:30
Examples of high performing school renovations applying prefabricated wooden elements in Austria
SPEAKER: Armin Knotzer

ABSTRACT. Introduction and motivation During the last 20 years increased efforts have been made not only by the national government through subsidies but also by research and development and by demonstration projects to increase the renovation rate in Austria. Since 10 years there is a strong development towards the application of prefabricated wooden elements for roof / façade constructions to support secure production actions off site for a quick and high on site renovation quality. Within the technology-programme “Building Of Tomorrow” of the Austrian Ministry of Transport, Innovation and Technology, together with financial support of the Austrian Climate and Energy Fund, a lot of example and demonstration buildings have been carried out last years. Lessons learned and useful experiences can be derived from measurements and studies on these buildings. And at the moment more projects on lowering the costs of the technology using prefabricated timber elements are implemented to be simple repeatable solutions for the masses of buildings.

Scope and method The European IEE-project „Renew School“ aims at promoting school renovations with prefabricated wooden elements and so helps to increase the quality of school renovations including IAQ and pupils’ comfort in Europe, and to increase the numbers of such renovation activities. Within the RENEW SCHOOL project frontrunner buildings have been analyzed and showed the quality and advantages of this renovation strategy. Some Austrian examples will be shown in this presentation, describing constructive details and solutions of the building services.

Results and conclusion What we learn from Austrian frontrunners of school renovations using prefabricated wooden elements is that high quality in terms of indoor air quality, visual and thermal comfort for teachers and pupils was reached automatically by intensified planning processes. The measurement results and the feedback from the users show that school renovations made in the “RENEW SCHOOL way” are performing well both in energy and comfort related targets.

13:40
Do new and renovated schools and kindergartens secure sufficiently high indoor environmental quality?

ABSTRACT. The present work is the part of the RENEW SCHOOL project granted within the Intelligent Energy Europe programme by European Commission with the aim to promote sustainable renovation of educational buildings (schools and kindergartens) that use timber prefabrication. Present paper describes the measurements in such buildings that are newly constructed or that have undergone renovation. Following the main objective of the project, these buildings use timber in the façade construction and have significantly reduced energy use (by at least 66% in terms of the primary energy). Besides, they use at least 20% energy from the renewable energy sources. The purpose of the measurements was to examine the quality of indoor environment in 10 buildings fulfilling these criteria located in different countries stretching from the north to the south of Europe. The quality was assessed by physical measurements of temperature, relative humidity, light intensity and carbon dioxide concentration performed for a period of up to two month between January and April 2015. The measurements were carried out in one representative classroom in each building. Besides, the pupils in these classrooms provided assessments of the environment and rated the intensity of their acute health symptoms. They used the questionnaire with scales made of smileys. The same scales were also used by the teachers working in these buildings to collect additionally their ratings. Similar measurements were carried out in five conventional educational buildings, where no renovations were performed for reference. Preliminary results indicate that the renovated and new buildings perform better as regards measured parameters of indoor environment than their conventional counterparts. Subjective evaluations made by pupils and teachers did not always match the physical measurements. There were considerable differences between the perceptions of the indoor environment by pupils and by teachers. The intensity of health symptoms was generally low with a tendency for elevated fatigue experienced by both the teachers and the pupils. In conclusion, there is no indication in the present work that the renovation of educational buildings would aggravate indoor environmental quality conditions, though it was observed that special solutions may be needed to protect against the episodes with elevated carbon dioxide concentration and thereby poor air quality, and to reduce the temperature in the classrooms, which although staying within the recommended limits were on the slightly higher side.

13:50
IEQ Evaluation in Schools: some Considerations about the Parameters PMV may be influenced by

ABSTRACT. There is evidence that the indoor environmental quality may have serious consequences on human’s health, comfort, and productivity. This is especially true in case of school environments, as children are physically still developing and, in comparison to healthy adults, will suffer the consequences of a poor indoor environment earlier. Consequently, IEQ in schools is a very investigated topic also due to the strict relationship with building energy performances. From the thermal comfort perspective, the assessment of comfort conditions is usually carried out by means of the PMV and the PPD indices. Unfortunately, the peculiarities of school environments (e.g wide classrooms, the absence of HVAC systems, the kind of activity and clothing) require high care to obtain a reliable analysis. Based on a wide experimental activity carried out since almost 20 years by the EQuaTeC research team, this paper is addressed to the main criticalities related to the thermal comfort assessment in schools. Particularly will be discussed the calculation of a sole PMV/PPD value to be attributed to the same classroom in the presence of more measurement positions, the effect of insulation value and, finally, how PMV index has to be used in non-air conditioned environments. Based on our experience, a reliable assessment of IEQ in schools has to be carried out by means of a clear protocol aimed to an unambiguous evaluation.

14:00
Ventilation rates and thermal comfort assessment in a naturally ventilated classroom
SPEAKER: Yacine Allab

ABSTRACT. Ventilation systems aim to provide a good indoor climate quality without generating discomfort and health problems among the building’s occupants. In fact, ventilation systems are meant (i) to guarantee good indoor air quality by providing and distributing fresh air to the occupied/breathing zone and (ii) to dilute and remove pollutants emitted by indoor sources. On the other hand, inadequate ventilation rates can induce discomfort issues and excessive energy consumption. This study focuses on the performance assessment of natural ventilation strategies in university classrooms, which are characterized by a high occupancy level and the necessity to provide high levels of comfort in order to facilitate the performance of intellectual work. The high occupancy level creates challenging conditions both in terms of internal gains and CO2 concentration. This paper presents an experimental performance assessment of four natural ventilation strategies applied to a university classroom: single side ventilation, cross ventilation, stack ventilation with and without window supply. Each strategy is evaluated in terms of thermal comfort and air change rate measurements. Indeed, this study combines thermal comfort assessment during occupancy period (physical parameter measurements and questionnaires) and air change rate measurements using tracer gas techniques during unoccupied periods. The study presents also a comparative analysis with a previous study conducted in winter 2014 using the same experimental procedure.

14:10
An Methodology for Quality Control and Draught Assessment of Room Ventilation Supply Using Laser Light Sheets

ABSTRACT. A common technique to investigate draught problems in a room is to make spot measurements of air velocity. This might identify where the draught problem is located but it does not necessarily identify the distribution and source of the problem. Usually visual inspections of the location of ventilation inlet and smoke experiments are next step to track the draught source. However, these methods do not provide an understanding of the air flow pattern in the room with sufficient resolution to necessarily identify the source of the draught problem. However, laser light sheets together with smoke seeding for on-site visualization of airflow in rooms might be useful for tracking down draught sources in rooms as part of a commissioning process. This paper reports on the first attempts to use this simple method to visualize and characterize air flow patterns in two different classrooms. The visualizations disclosed the air movements, and it was possible to record the movements using a standard smartphone camera. From the movements it was possible to qualitatively assess the overall airflow patterns of the room. The resolution of the video recording was also sufficient to be processed in particle image velocimetry software to gain overall flow pattern visualization, if not accurate readings. The latter result indicates that there could be a potential for real-time velocimetry processing by smartphones but the method in general needs further investigation and documentation.

14:20
Indoor climate and energy standard of school buildings with different ventilation strategy

ABSTRACT. Indoor climate quality as well as energy standard of school buildings is very important subject. In this context it seems obvious that mechanical ventilation with heat recovery (HR) is better solution than natural/hybrid ventilation. However, data collected within RenewSchool Project showed that in some cases natural ventilation provides better indoor climate than mechanical ventilation with HR. At this point the question arises whether it is possible to provide required indoor climate and similar energy consumption in school classrooms with natural/hybrid ventilation as in buildings with balanced mechanical ventilation with HR? The paper presents comparison of energy performance and indoor climate in typical school classroom with two different ventilation strategies: mechanical balanced ventilation with heat recovery (HR) and natural/hybrid ventilation. For both types of ventilation the model of energy performance as well as calculation of indoor climate were carried out. The primary energy consumption (heating energy and electricity used for ventilation) in rooms with similar ventilation rate and thermal comfort were analysed and commented. It was showed that providing thermal comfort is not problematic, but energy performance and indoor air quality can vary a lot between different ventilation strategies. In analysed cases the classroom equipped with mechanical ventilation with HR, for heating and ventilation, consumed about 40% of primary energy less then the one with natural/hybrid solution. In a moderate climate (Europe, Poland) it is possible to meet requirements of indoor climate and keep energy consumption on reasonably level in classrooms with mechanical ventilation with HR as well as in classrooms with natural/hybrid ventilation.

14:30
Analysis of ventilation strategies for the nearly zero energy retrofit of a kindergarten

ABSTRACT. The scientific literature often reports examples of educational buildings with extremely poor ventilation performance. An in-field investigation for the environmental and energy assessment of a kindergarten in Italy in Milano, confirmed that operable windows were not opened when the average daily outdoor temperature dropped below 14 °C, jeopardizing indoor air quality and kids learning performance. A numerical model for the dynamic energy simulation of the school building was developed to optimize the thermal insulation of opaque and transparent envelope, the solar control strategy, checking energy needs and uses to implement a zero-energy approach. Different ventilation strategies were therefore simulated, in order to evaluate the one that better fitted a general project of deep energy retrofit of the building, including building envelope and systems. The scenarios adopting hybrid ventilation also during nighttime show very high potential to ensure summer indoor comfort performances. Both energy and thermal comfort conditions were evaluated and a trade-off between them was established. Nighttime ventilation showed to be extremely effective in improving thermal comfort conditions, during the cooling season. It resulted much better than mechanical ventilation in the simulated case study. Simulations show that under moderate weather conditions and if the building is properly operated (ventilation, lighting and solar screening systems) the retrofitted building may perform well also without additional active cooling.

13:30-15:00 Session TS 4: High integration of renewable sources in community energy supply utilising low exergy systems (IEA EBC Annex 64)

Organiser: IEA EBC Annex 64: "Optimised Performance of Community Energy Supply Systems with Exergy Principles – LowEx Communities"

www.annex64.org  

 

Short description:

Communities are characterised by a wide range of heating and cooling energy demands. This energy is mainly provided by the combustion of fossil fuels, which is responsible for greenhouse gas (GHG) emissions. While much has already been achieved, there are still large potentials in providing heating and cooling energy with lower or without CO2 emissions. At the community level, different renewable sources are available that do not involve combustion processes. These energies are often characterised by high fluctuations and different exergy levels or ‘qualities’: e.g. electricity (high-exergy) from photovoltaics or low temperature (low-exergy) heat from solar energy or waste heat. Low energy qualities are of particular interest, because they can supply most heating and cooling demands very efficiently. Exergy calculation still is a major challenge nevertheless. To identify potential savings and synergies holistic analysis of energy flows is necessary. The application of exergy principles is especially important, allowing the detection of different available energyquality levels and the identification of optimal contribution to an efficient supply. From this, appropriate strategies and technologies with great potential for the use of low-valued energy sources (LowEx) and a high share of renewable energies for heating and cooling of entire cities can be derived. In the framework of the EBC project ‘Annex 64: LowEx Communties’ advanced technologies will be adapted and further developed to realise the identified potentials. An additional task is to develop and test appropriate business models for the implementation on energy systems based on low exergy principles.


Presentations:

1) Optimising Community Energy Supply with Exergy Principles. Dietrich Schmidt, Fraunhofer IBP/GER.

2) Addressing different approaches for evaluating Low-Exergy Commuities. Sabine Jansen, DTU/NL and Forrest Meggers, Princeton/USA,

3) Energy and exergy analyses of Bjerringbro low-temperature district heating area. Klaus Lund Nielsen, DTU/DK.

4) Renewable Low-Temperature District Heating of a New Housing Area in Kassel, Germany – A Case Study of IEA. Janybek Orozaliev, University of Kassel/GER

5) Assessment and methods for optimised community supply based on exergy principles. Ivo Martinac, KTH – The Royal Institute of Technology / SWE

6) Methodology for the assessment of temperature reduction potentials in district heating networks by demand side measures and cascading solutions. Ralf-Roman Schmidt, Austrian Institute of Technology / AT

7) Simulation and exergetic analysis of renewable multi-generation units for a building group. Anna Kallert, Fraunhofer IBP/GER

Location: Latinerstuen
13:30-15:00 Session TS 9: Sustainable Energy for Data Centres (EU RenewIT, GENiC and DOLFIN)
Location: Gæstesalen
13:30
Optimizing energy efficiency for next-gen data centres
SPEAKER: Lara Lopez

ABSTRACT. Energy consumed by computation and cooling represents the greatest percentage of the average energy consumed in a data centre. As these two aspects are not always coordinated energy consumption is not optimized. Also the penetration of energy coming from renewable sources has received limited interest due to the high investment costs needed to integrate them. Basically, data centres lack of an integrated system that jointly optimizes and controls computing, cooling, energy generation, energy storage, and waste heat recovery in order to reduce energy consumption on the demand side and increase the usage of renewable sources on the supply side. GENiC project is addressing this topic through a novel scalable, integrated energy management and control platform for data centre wide optimization. The approach proposed by the project integrates monitoring and control of energy produced (local power generation and its sources, waste heat recovery) versus the energy consumed (computation, communication, data storage, cooling) inside a data centre. GENiC offers a distributed system architecture where the components within the platform exchange information through a message broker system. The Supervisory Intelligence (SI) component is located at the top of the hierarchical system level control architecture and coordinates the three primary data center functions: workload, thermal, power&RES. Energy optimization and control algorithms are designed and implemented to achieve the high-level objectives of data centre such as minimization of energy, cost, emissions and maximization of renewable usage. All these measures and considerations will be represented in an integrated platform that provides a set of services to support energy optimization and a decision support toolkit that targets a reduction of a 25% of the energy consumed plus the improvement of the operational performance (<1.3 PUE) with the target of achieving 80% renewable usage.

13:40
Simulation of on-site generation CHP systems for large-scale data centre
SPEAKER: Verena Rudolf

ABSTRACT. INTRODUCTION: As part of the RenewIT project, thermal and electrical power supply concepts for data centers have been developed. The main goal of these efforts is to substitute fossil fuels by renewable energy sources and additionally raise the efficiency of the energy concepts. Out of the fourteen concepts, the four concepts with combined heat and power production (CHP) provide the most promising solutions. Therefore, great efforts have been made to increase the efficiency of software used to model and simulate these concepts. METHODS: One of the concepts with CHP, the system with syngas reciprocating internal combustion engine, is presented to show the methodology (Fig 1): Modeling and simulating non-series products with EBSILON is the first step. Then the complex part load behavior is transferred into a correlation equation of heat and power, and finally this information is integrated into TRNSYS in order to increase data processing and minimize computing time. With TRNSYS various parameter studies of thermal and electrical power supply concepts were conducted to investigate the influence of data center power, location, etc. Calculating the detailed subsystem of the CHP within these studies would have extended the computing time enormously. For designing non-series products, the information given from literature and data sheets provided by the manufacturers is rare. Therefore, detailed stand-alone models of the CHP processes have been developed with EBSILON in order to analyze their steady-state part load behavior. Fig 2 shows the example of the system with syngas reciprocating internal combustion engine with biomass conversion, conditioning of the crude gas and the engine. The two main outputs are the derivation of the relation between the electrical and the thermal efficiency of the system for different loads as well as the power to heat ratio at different power ranges. To use this information in TRNSYS efficiently for further transient calculations, correlation equations compromise the information. RESULTS and DISCUSSION: The results of the design and part load steady state simulations of the system with synthetic gas reciprocating engine are demonstrated in Fig 3 and Fig 4. While Fig 3 displays the electrical and thermal efficiency at different loads, fig 4 shows the power to heat ratio in different electrical power ranges. The correlation between electrical power P_el and thermal power Q ̇_CHP generated by the system with synthetic gas reciprocating engine can be described with a potential approach as follows: P_el=0.327· (Q ̇_CHP)^1.172 This result is then transferred into the macro that was modelled in TRNSYS using a look-up table function. CONCLUSION: Regarding intermediate results of the RenewIT project, based on the fourteen concepts, the four concepts with CHP provide the most promising solutions. One of the concepts with CHP, the system with syngas reciprocating internal combustion engine system, is presented to show the methodology of modeling and simulating non-series products with EBSILON, transfer the complex part load behavior into a correlation equation of heat and power and integrate this information into TRNSYS to increase data processing and minimize computing time.

13:50
An Energy Consumption Optimization Platform For Green Data Centres

ABSTRACT. During the last few years, the energy sector has faced two important problems triggered by the increase of the number of Data Centres (DC), and the instability of the Smart Grids while following the electricity demand-response model. The average server utilization in DCs is often below 30% of the maximum server load and energy demand and consumption is increasing year over year, mostly due to overdimensioning and non-optimal allocation of DC resources. In the framework of the DOLFIN project (www.dolfin-fp7.eu), we developed an energy Consumption Optimisation Platform (eCOP) to monitor and optimize energy consumption at the single DC level. The DOLFIN eCOP system is capable of providing continuous monitoring, dynamic control and adaptive optimisation of the DC infrastructure, including control of power condition of ICT and non-ICT devices (e.g. HVAC). Our eCOP platform implements energy benchmarking, dynamic control, and adaptive optimisation of the DC infrastructure, including specific functionalities for metrics calculation and energy data collection and storage. DOLFIN eCOP also allows to define energy policies applicable to both the ICT and HVAC infrastructure of the DC, thus regulating conditions under which specific control and optimization actions can be applied. The energy models implemented in the eCOP platform are common throughout the whole DOLFIN Software Platform, which also comprises a Synergetic Data Centres platform (SDC) for the energy-efficient allocation of demands across a network of distributed co-operating DCs. Some Key Performance Indicators (KPI) for energy consumption used by eCOP platform for optimization include the Physical Server Energy Consumption, Average VM Energy Consumption, Average Application Energy Consumption and Application Energy Consumption. These metrics are used and processed by the various eCOP functional elements to implement optimizations. Key for the eCOP activity is the Energy Efficiency Policy Maker and Actuator, which implements the intelligence for the application of energy optimization policies. Core elements of the eCOP actuator are: a) The Policy Maker which schedules the activation of policy enforcements on the basis of the DC status and the information collected from the various systems. This module implements a closed control loop following the principles of MAPE-K adaptation control loops to implementing both monitoring, analysis, planning and executing components. b) The Prediction Engine which provide forecasts for all measurement types and DC infrastructure resources that are supported. This module uses a training model based on Support Vector Machines for Regression (SVR) applied over the complete set of acquired data in order to get an accurate representation of trends for various [resource, measurement_type] tuples. c) The Optimizer, which implements the optimal strategy for re-allocating DC resources at both IT and non-IT levels to achieve the objectives set by the Policy Maker for the active policy in use. The DOLFIN eCOP platform is currently in prototype stage and is under consolidation through validation tests in three interconnected laboratory environments, each emulating real-life DCs.

14:00
Simulation based-assessment of Thermal aware computation of a bespoke data centre

ABSTRACT. The role of Data Centres (DCs) as global electricity consumers is growing rapidly due to the exponential increase of computational demand that modern times require. Control strategies that minimize energy consumption while guaranteeing a correct operation are essential to achieve sustainable and energy efficient DCs. Unfortunately, the development and testing of novel control strategies are often slowed down, if not discarded. This is generally due to the lack of access caused by safety and economic reasons. Alternatively, simulation experiments represent a “safe” environment to test novel control strategies, accelerating the process for their implementation in physical DCs.

A virtual testbed of a small-size DC (C130 DC), developed within the GENiC project, supports the development and dynamic testing of control and energy management algorithms. This virtual testbed enables one or various distributed developers to, once complying with the I/O structure, interactively test the dynamic performance of their algorithms over Internet. This performance assessment can be analyzed at various levels of resolution (from a third of a rack to whole building level).

This paper describes the main features of such virtual testbed, and uses it to present a simulation-based assessment of thermal aware computation on the C130 DC. Located in Cork (Ireland), the C130 DC has 30KW capacity and its layout follows a hot aisle - cold aisle arrangement without containment. Literature shows that a coordinated control involving workload allocation and operation of the cooling systems can minimize the total DC energy consumption while reducing the risk of hot spots in the whitespace. For this, thermal characteristics of the whitespace of the C130DC will be represented by the supply heat index (SHI). This creates a set of thermal preferences that will be fed into the workload allocation strategy.

The influence of thermal aware computation on the whitespace environment, as well as on the performance of the cooling system is evaluated and quantified with the virtual testbed. Finally, the benefits of a coordinated Thermal aware computation with respect to Total DC consumption are discussed.

14:10
Online tool to evaluate the implementation of energy efficiency strategies and renewable energy into data centre portfolio

ABSTRACT. Introduction

Nowadays, the total energy demand of data centres accounts for around 2% of the worldwide energy consumption and is still growing. This is why data centre industry and researchers are undertaking efforts to implement energy efficiency measures and to integrate renewable energy into its portfolio. Oró et al. [1] presented an overview of the current data centre infrastructure. The researcher summarized a number of currently available energy efficiency strategies and renewable energy integration into data centres Moreover, Oró also commented the main numerical models developed in order to characterize the data centre facility. In the framework of RenewIT project [2], a European funded project, holistic and dynamic energy models to characterize the energy performance and the life-cycle economic impact of data centres have been developed. The final outcome of the project is the RenewIT tool, a public web-site platform, aimed to evaluate different energy efficiency strategies in pre-design phase, as well of use of renewable-based supply energy systems.

Methodology

The RenewIT tool incorporates the most promising electrical and cooling systems for data centres.. The computational engine of the tool is based on meta-models which are simplified models generated by surface-response methods from detailed dynamic energy models using TRNSYS software. Up to 18 advanced dynamic energy models have been evaluated and the solutions which shown higher potential have been analysed in detail though dynamic simulations. The paper will describe the method followed to derive the metamodels from the TRNSYS simulations and the key parameters will mainly influence on energy performance of data centres. The requirements, the functionality and the final layout of the RenewIT Graphical User Interface (GUI) has been developed in close collaboration with data centre stakeholders such as industrials, planners, managers and owners.

Results and Discussion

The paper will describe the RenewIT Tool which is implemented in a friendly-user web-site platform, which will be available at the end of the project (September, 2016). The GUI is divided in different sections: - General information of the data centre. - IT information. - Power and Cooling system implemented. - Advanced solutions and renewable energy integration. - Results of the simulation. The tool shows energy and economic results and allows comparing up to five different data centre configuration in 61 European locations. An example of application of the tool and results obtained will be described.

Conclusions

A friendly-user tool in order to evaluate different technical solutions for energy systems in data centres has been developed. Main features of the tool, both the computational engine and the graphical user interface are described, together with an example of use.

References

[1] Oró, E., Depoorter, v., Garcia, A., Salom, J. Energy efficiency and renewable Energy integration in data centres. Strategies and modelling. Renewable and Sustainable Energy Review. 2015;42:429-445. [2] RenewIT project. Available online in http://www.renewit-project.eu [Accessed November 2011]

14:20
Numerical analysis for potential heat reuse in liquid cooled data centres
SPEAKER: Eduard Oró

ABSTRACT. Introduction

During the last years the rapid increase of cloud computing, data storage and internet use have resulted in a dramatic growth in the number of data centres. These unique installations work 24 hours a day, 365 days a year, and the miniaturization of the components and increase of the processing power results in a huge energetic density. As a consequence, the energy consumption and carbon footprint of this emergent industry started to become a considerable worldwide concern. Most of the power consumed by the Information Technology (IT) equipment is converted in excess heat, which must be removed to avoid the damage of the equipment. Traditionally the refrigeration in these unique facilities has been done by air cooling systems. However, due to the exponential increase in IT energy density, in few years the energy density of the IT equipment will reach values up to 50 kW/rack and therefore the solely use of air cooling system will be insufficient to evacuate all the heat generated by the servers. To overcome this problem the data centre industry is already investigating and implementing the use of liquid cooling systems due to the higher heat removal capacity and the ability to cool specific system components to a greater degree. This study aims to develop and to validate with experimental data a dynamic energy model able to predict the operational behaviour of liquid refrigerated data centre.

Methodology

A unique micro data centre test bench with an IT power capacity of 1.2 kW has been designed and built in the Catalonia Institute for Energy Research (IREC) facilities. Moreover, the relationship between server usage and server consumption was developed for different common IT loads (HPC, data and web).

Results and Discussion

Two different validation processes are evaluated in order to guarantee the robustness of the model. The first is to validate the thermo-physical characteristics of the system and the second is to validate dynamically the model proposed. The validation process proves the consistency and robustness of the dynamic model developed. Therefore, the model developed can be used to analyse the potential heat reuse of real liquid cooled data centres in different applications.

Conclusions

A dynamic energy model for potential heat reuse in liquid cooled data centres have been developed and validated with experimental data. The benefit of developing this model not only will help to well configure the cooling system for a specific data centre facility but will allow analysing the potential heat reuse from data centres to different heating applications such as building heating, conditioned swimming pool, green house, etc.

13:30-15:00 Session WS 21: Coupling HVAC + Refrigeration + Lighting systems in shopping centres: technology solutions and modelling approach (IIF-IIR and EURAC)

Organisers:

  • Eurac Research, Institute for Renewable energy
  • IIF-IIR, International Institute of Refrigeration

 

Scope:

This workshop is intended to present and discuss tools and solutions for an effective energy-retrofit of shopping malls. It will take advantage of the participation of experts from the CommONEnergy project, who will bring their expertise and open a fruitful debate on the outcomes of the project. The result of the workshop can be an outline for a guideline on the energy-refurbishment of shopping malls. 

Full description of workshop at: http://www.rehva.eu/?id=1119

Location: Bondestuen
13:30-15:00 Session WS 22: Agenda for Ventilation and Air Infiltration 2020 and beyond: knowledge gaps, research priorities and the need for innovation (AIVC)

Organiser: AIVC


Presenters:

Pawel Wargocki and Peter Wouters


Background:

The primary objective of the Air Infiltration and Ventilation Centre (AIVC) formed by the IEA (International Energy Agency) Energy in Buildings and Community (EBC) Programme in 1979 is to provide reference information on research and development in the fields of air infiltration and ventilation, which are key aspects to achieve healthy and comfortable highly energy efficient buildings. This Annex has produced a number of landmark reports and guides in addition to organising events such as the annual AIVC conference, and many more specialized workshops and webinars. Since 2011, the AIVC's activities are structured around projects integrating activities such as webinars and workshops and produce position papers, technical papers, technical reports, etc. The full list of existing projects is available on the AIVC website, http://www.aivc.org/resources/collection-publications/aivc-projects.


Scope:

This workshop will attempt to look into the future needs concerning ventilation and air infiltration, including comfort and health and considering all building types and climates.

Full description of workshop at: http://www.rehva.eu/?id=1111

Location: Harlekinsalen
13:30-15:00 Session WS 24: Energy refurbishments (REHVA Task Force)

Presenters:  

Discussion Moderator: Branislav Todorović, ENB Editor at Large

Chairs and Speakers: Marija S.Todorović, Sergio Vega, Ioan Silviu Dobosi, Tim Jonathan, Birol Kilkis

 

Scope:

Workshop will address holistic deep – Renewable Energy Sources (RES) integrated refurbishment of existing buildings to the level of energy efficiency and renewable energy sources (RES) integration that can lead cost-effectively to Zero CO2 emission and smart Energy+ (E+) buildings and settlements. Presented will be cutting-edge and emerging technologies seeking more density RES integrated buildings solutions, developing modelling predictive control based Smart Grids as integration of buildings at district level, taking in account standardization, different barriers, weather extremes including catastrophic events and building’s resilience relevant features. Technical solutions of houses energy supply systems, energy efficiency and energy balances, as well as HVAC system design creativity, related approaches to the loads and energy demands minimization, harmonization of passive and active indoor environment control, innovations and sustainability taking in account life cycle and embodied energy will be presented of the most challenging projects including some of the Solar Decathlon Europe edition (encompassing Big data collected by an innovative measuring/monitoring Transdisciplinary Synergetic Modelling and Monitoring System and Program – TSMS, and TSMP). 

Full description of workshop at: http://www.rehva.eu/?id=1120

Location: Columbinesalen