ABSTRACT. Universities are one of the main consumers of energy in urban environments. Their reliance on external energy sources—particularly fossil fuels—can contribute substantially to emissions, highlighting the urgent need to transition to cleaner and more sustainable energy supplies. This study evaluates the potential for renewable energy integration and low-carbon technologies at the city scale, using the Vera campus of the Universitat Politècnica de València (UPV) as a representative example of a small urban system. A combined quantitative and qualitative approach was applied, including historical consumption analysis, assessment of local renewable potentials, empirical data from technologies implemented on campus, and complementary energy system modelling. Technologies considered include solar photovoltaic and thermal, wind, biomass, and the replacement of gas-fired heating with heat pumps (geothermal and aerothermal). Results indicate that on-site renewables could cover approximately 48–52% of the campus’s energy demand, with the largest contributions from solar photovoltaic (28%), geothermal (11%), and aerothermal (8%), followed by solar thermal (1%), wind (1%), and biomass (<1%). These findings suggest that, even with substantial investment in a renewable energy roadmap, additional energy would need to be sourced off-site and complemented by building retrofits, nature-based solutions, and social and behavioural measures. This study provides an adaptive framework to guide other universities in implementing renewable energy solutions while addressing institutional, technical, and strategic constraints, and encourages exploring additional alternatives to achieve a greater degree of energy transition on campuses.

ABSTRACT. Cooling Degree Days (CDD) are widely used as a simple indicator for estimating cooling energy demand; however, conventional approaches rely solely on the difference between outdoor air temperature and a reference base temperature. This simplification often leads to significant underestimation of cooling loads, particularly when compared to Heating Degree Days (HDD), which generally provide reliable estimates for heating demand. To address this limitation, an innovative methodology for calculating CDD is proposed, incorporating additional climatic parameters that strongly influence cooling requirements. The model integrates solar radiation, sky temperature, and cloud cover conditions into the calculation framework in a straightforward way. By embedding these factors, the methodology captures the combined effects of radiative gains and atmospheric conditions on building cooling loads, which are neglected in traditional temperature-based approaches. The proposed formulation maintains the simplicity and interpretability of degree-day metrics while enhancing accuracy and applicability across diverse climates and building typologies. Preliminary validation against dynamic simulation results demonstrates that the enhanced CDD metric significantly improves correlation with actual cooling energy demand, reducing systematic bias observed in standard methods. This advancement provides a practical tool for energy analysts, designers, and policymakers seeking more reliable cooling load estimations without developing complex simulations. The methodology thus represents a step forward in bridging the gap between simplified indicators and real-world cooling performance, supporting better planning and optimization in the context of increasing cooling needs under climate change.

ABSTRACT. This research study investigates the energy footprint and the prospects for improving energy efficiency through the management and utilization of the environmental sources, the passive in construction techniques and the integration of Renewable Energy Sources (RES), aiming at promoting sustainable and eco-friendly development. The research focuses on a refurbished academic institution in Chania. The costing stone building is transformed to the first seed bank of Greece and the second in the Mediterranean region. The proposed structures have been constructed using natural materials. The study requires an analysis of the materials in conjunction with the installation of Renewable Energy Sources, specifically Hybrid Solar Systems. This application aims to reduce energy consumption and enhance the efficient management of natural resources, as their production and application are based on the principles of green bioclimatic design. Initially, meteorological data is collected and processed using the Elements Weather software to simulate the climatic dynamics of the study area. Subsequently, the building is modelled using SketchUp, based on the floor plan data provided through AutoCAD. In the next step, the required meteorological data, building material properties, energy consumption parameters, and thermal zone operations are incorporated into Open Studio. Two simulation scenarios are developed: the first analyses the energy performance of the buildings without integrating RES, while the second incorporates design data for hybrid solar systems. Through this process, energy consumption, thermal fluctuations, and CO2 emissions are calculated for each scenario. Finally, the results of the two scenarios are compared to evaluate the energy efficiency and environmental effectiveness of the applied strategies.

ABSTRACT. Renewable Energy Communities (RECs) are increasingly recognized as an effective framework for enhancing the integration of renewable generation, energy storage systems, and active energy sharing at the local level. In this context, robust modeling approaches are required to analyze energy flow dynamics and support the assessment of different energy management strategies. This paper presents a methodology for modeling and simulating energy flows within RECs. The proposed approach models electricity demand, photovoltaic generation, and battery storage to characterise energy production, self-consumption, and storage dynamics. The framework compares two configurations: standalone building operation and coordinated management within a REC, using rule-based control logics to assess differences in energy and economic performance. Multiple load profiles and different types of users are considered to capture demand heterogeneity within the community. The proposed framework is applied to a case study of a REC located in Italy, allowing the analysis of energy flow interactions under representative operating conditions and the comparison of different seasonal characteristics. In addition, key performance indicators such as self-consumption indices and system operational costs are evaluated to assess the impact of different energy management strategies. The results demonstrate that participation in the REC leads to tangible energy and cost savings compared to standalone operation. In addition, coordinated management within the REC reduces grid dependency, thereby lowering the impact on the electricity network.

ABSTRACT. Across the European Union, regulatory frameworks place strong em-phasis on building decarbonization as one of the key priorities for transforming district heating (DH) systems. Achieving the targets of the Energy Efficiency Directive by 2050 will be a major challenge for dis-trict heating operators and related stakeholders. Although advanced heat generation technologies offer great potential for integrating re-newable energy sources (RES), their impact on DH systems remains unclear due to diverse economic constraints. In order to stimulate the balanced and efficient development of RES, it is necessary to ensure the robust planning of DH systems by implementing reliable modeling techniques. This paper investigates the relevance of low-grade RES technologies through a case study of the Neveronys boiler house in the Kaunas district (Lithuania). A comprehensive heat production analysis was performed to identify a technically feasible and economically via-ble solution to replace natural gas and achieve a 90% share of renewa-ble heat. The study assessed the potential of local waste and environ-mental heat, including treated wastewater heat sources, industrial waste heat, river water, geothermal resources, and ambient air. Using ener-gyPRO software, six system configuration scenarios were examined, combining CO₂ heat pump (HP), thermal energy storage (TES), electric boilers, and biogas usage. The best among the analyzed solutions was found to be a 0.7 MW air-to-water CO₂ HP with a 60 m³ short-term TES. This scenario, with 40% financial support, is expected to reach a payback period of 8 years, reduce CO₂ emissions by 90%, and main-tain competitive heat production costs, making it a replicable solution for similar DH systems.

ABSTRACT. The European energy transition is reshaping skill requirements in the construction sector, creating a growing need for training approaches that align workforce competencies with evolving technological and regulatory frameworks. In response, the RESSKILL initiative develops a network of local Knowledge Hubs to support the co-creation of targeted micro-credentials and training programmes for construction professionals. These hubs bring together employers, training providers, public authorities, and practitioners to align skills development with place-based needs, facilitate knowledge exchange, and enable continuous adaptation to sectoral change. This paper presents a framework for the design, implementation, and governance of local stakeholder Knowledge Hubs. The framework integrates structured stakeholder mapping, identification of key professional profiles, and multi-level governance arrangements linking local hubs with coordination and project-level structures. The framework was applied across four local hubs in four European countries (Spain, Italy, Greece, and Ireland), engaging stakeholders through surveys, workshops, working groups, and consultation activities. The paper analyses how the framework informed hub design, organisation, and facilitation, including stakeholder engagement processes, mechanisms for knowledge sharing, feedback on training needs and materials, and coordination across governance levels. The results contribute a transferable framework that can be adapted to different national and local contexts to support workforce upskilling and reskilling in the construction sector in the context of the energy transition.

ABSTRACT. The residential building stock accounts for nearly 40% of global energy use and 37% of CO₂ emissions, making the decarbonisation of existing buildings a central requirement of the Energy Performance of Buildings Directive. In Italy, a significant share of residential emissions is linked to energy inefficient dwellings constructed before the introduction of effective thermal regulations. This study presents a stock-level, data-driven and probabilistic methodology to support policy-relevant prioritisation of retrofit interventions within the residential sector. The analysis is based on representative residential archetypes capturing variations in building age, typology, and heating systems. National housing statistics are used to define and weight archetypes, ensuring consistency with national scale indicators. A statistically representative sample is generated using proportion-based sampling, while uncertainty in building and system parameters is addressed through Monte Carlo simulation. Heating-related energy demand is estimated using a climate-adjusted thermal balance model calibrated with Italian heating degree days, heating season profiles, and solar radiation data. Energy consumption is converted into carbon dioxide emissions using fuel-specific emission factors aligned with regulatory practices. The framework enables comparative assessment of retrofit pathways, including uniform renovation strategies and targeted interventions focused on the most emission-intensive parts of the housing stock. By explicitly addressing uncertainty and focusing on structural building characteristics rather than behavioural variability, the methodology provides robust decision support under constrained financial and administrative resources. The approach is transparent, scalable, and transferable to other national contexts where comparable building, energy, and climate data are available.

ABSTRACT. The critical need for energy efficiency and decarbonization in public buildings requires the achievement of two conflicting objectives: reducing energy consumption while maintaining or increasing the well-being of indoor occupants. According to Directive (EU) 2024/1275 all new buildings must be zero-emission by 2030 and all buildings in the European building stock by 2050. This involves significantly increasing the insulation of buildings, and this can cause poor ventilation, leading to a deterioration in indoor air quality (IAQ). Furthermore, energy consumption and indoor air quality are linked to the habits and presence of occupants. Reconciling comfort and environmental sustainability therefore requires a multifaceted approach that includes technological interventions, intelligent management, and participatory users’ behavior. In this context, the IBIS ECO project integrates digital technologies through a multi-level approach centered on a decision support system (DSS IBIS ECO), designed to manage buildings in an “intelligent” way, balancing energy performance with indoor environmental quality (IEQ). This integration is achieved through several fundamental technological pillars: IoT monitoring and advanced sensing (energy consumption, air quality and environmental parameters); cloud infrastructure and artificial intelligence (data collected by the sensors is transmitted to a cloud platform and processed by artificial Intelligence (AI) and machine learning techniques); decision support and optimization tools to identify the most efficient interventions; interactive dashboards and user feedback that provide real-time information to different types of users to help identify anomalies and encourage awareness. By validating this system in real-world demonstrators in the Basilicata Region (Southern Italy)—a school in Montemurro and a university hall in Matera—the project demonstrated that integrating these digital technologies allows for a shift from static building management to a proactive, data-driven approach that optimizes both sustainability and human well-being

ABSTRACT. Climate change is increasingly challenging the performance and resilience of the built environment through rising temperatures, intensified heatwaves, and more frequent extreme weather events. In Mediterranean countries such as Spain, much of the existing building stock is particularly vulnerable, having been designed for climatic conditions that no longer reflect present or future realities. At the same time, buildings represent a major share of energy consumption and greenhouse gas emissions, placing the sector at the center of both climate change mitigation and adaptation efforts. This work evaluates the impact potential of climate-resilient retrofitting strategies for the Spanish building stock under current and future climate conditions. The proposed framework integrates data-driven building stock characterization, dynamic building performance simulation, experimental validation, and multi-criteria decision analysis. National-scale open datasets (including cadastral records, energy performance certificates, census data, and socio-economic indicators) are processed using automated Python-based clustering methods to identify representative reference buildings. These typologies are 3D modelled in DesignBuilder and dynamically simulated in EnergyPlus across all Spanish climate zones and major end uses. A comprehensive set of climate-resilient retrofitting strategies, including envelope measures, nature-based solutions, and renewable-based systems, is assessed under multiple climate scenarios derived from Shared Socioeconomic Pathways. Simulation automation and post-processing are achieved through a Python workflow integrating the EnergyPlus API. Results provide a comparative evaluation of retrofitting strategies in terms of energy performance, indoor thermal comfort, technical feasibility, environmental and economic impacts, scalability, and regulatory compliance. The proposed methodology supports evidence-based policymaking and investment planning, contributing to a more resilient and sustainable Spanish building stock.

ABSTRACT. Decarbonizing the existing building stock is essential to achieving climate neutrality targets. While conventional thermal insulation, such as expanded polystyrene (EPS), remains one of the most widely used façade insulation materials in European retrofit practice, bio-based alternatives, like straw-based insulation boards, offer promising low-carbon pathways. This study evaluates the energy performance and summer overheating behavior of straw-based façade insulation compared to conventional EPS within a typology-based renovation framework. Representative residential typologies from existing Hungarian building stock are analyzed, covering different construction periods and envelope characteristics. For each typology, renovation scenarios are developed applying either EPS or straw-based insulation designed to achieve equivalent thermal transmittance targets. Dynamic whole-building energy simulations are conducted to assess annual heating energy consumption and summer overheating risk under both present and future climate conditions. Besides thermal conductivity differences, material density and specific heat capacity are also incorporated into the dynamic simulations, allowing the assessment of their influence on indoor temperature and overheating exposure. The study addresses a current research gap, as bio-based façade insulation materials are rarely evaluated using typology-scale dynamic simulations that account for both heating demand and summer performance. Beyond individual building results, the heating energy saving potential is extrapolated to estimate the possible impact at the building stock level. By integrating typology-based modelling and climate-sensitive dynamic simulations, the research provides decision-support insights for large-scale renovation strategies in Central and Eastern European contexts, where substantial energy-saving potential remains in the residential sector.

ABSTRACT. The decarbonization of the construction sector is one of the most urgent environmental challenges of our time, given its significant contribution to global CO2 emissions. The existing building stock represents a largely untapped resource in addressing this challenge. Across European cities, large quantities of office space have become vacant or obsolete, accelerated by structural shifts in working patterns following the COVID-19 pandemic. In the context of a persistent housing shortage, the transformation of office buildings into housing offers a systemic response: it addresses two crises simultaneously, minimizes embodied carbon relative to demolition and new construction, and supported by recent changes in French legislation and financing instruments contributes to the production of much needed housing. This article examines how the reuse of existing load-bearing structures can generate significant avoided emissions. Using Life Cycle Assessment methodology (EN 15978, INIES database), it quantifies the embodied carbon savings achieved through structural reuse in two completed Parisian office-to-housing conversions: the Student Residence in Arcueil by TVK (2010) and the PONG building by CALQ (2024). The two cases represent distinct transformation approaches: structural shell reuse with façade replacement, and structural shell plus façade retention, enabling a direct com- parison of the carbon value of each decision.

ABSTRACT. Holiday homes and park homes are an important but under studied in the UK built environment. Holiday homes are associated with BS EN 1647 and park homes are aligned with BS 3632. This paper reviews the main factors shaping thermal performance and low carbon transition in UK holiday homes and park homes. It argues that performance is influenced not only by nominal fabric standards, but also by construction quality, airtightness, compact layout, heating system integration and infrastructure constraints. Improved U-values do not necessarily ensure better in-use performance where heat loss through infiltration remains and insufficiently addressed. Heating and domestic hot water provision are also constrained by compact internal layouts and limited electrical capacity at park level. Current sector trends show increasing interest in integrated packages, including fabric, electrified heating and hot water, compact thermal storage, PV integration and load controls. However, the evidence base remains uneven. Key gaps include limited monitored in-use performance data, weak understanding of occupancy and control behaviour, insufficient evidence on ventilation and indoor air quality, and limited knowledge of how system performance varies across different climates and operating conditions.

ABSTRACT. The UK’s housing stock, especially terrace houses, poses a substantial obstacle in attaining nearly zero energy consumption owing to its old age, building techniques, and poor energy performance. This systematic literature review examines the current state of research on technical retrofitting solutions aimed at transforming these dwellings into high-performance, low-energy homes. This paper presents a PRISMA-based systematic review of 24 peer-reviewed studies (2019–2026) on five key dimensions: energy retrofit strategies and models, life cycle analysis and carbon management, energy efficiency and fuel poverty, indoor environment and overheating, and other emerging trends to identify gaps, evaluate effectiveness, and propose future directions for research and practice. Life cycle assessment underscored the need to balance short-term energy efficiency with long-term decarbonisation, while tackling energy poverty, demands fair approaches by avoiding in-creased overheating hazards. The results indicated many retrofit approaches, including improvements to insulation, the addition of renew-able energy sources, and advanced technologies, hold potential, but their suitability depends on structural limitations, economic feasibility, and how occupants interact with them. The paper highlighted the necessity for comprehensive strategies blending technical, economic, and social aspects to attain sustainable retrofitting results. Drawing together varied viewpoints, this paper established a basis for policymakers, practitioners, and scholars to progress the decarbonisation of UK terrace housing.

ABSTRACT. Modular construction can provide a higher quality control and quicker construction timeline as well as a reduction of material waste compared to traditional construction methods, making it possible to achieve a more sustainable built environment. In addition, since in modular construction the building components are manufactured off-site in controlled factory settings, a stronger control of thermal and energy performance is possible. The present study focuses on the analysis of the energy performance of two modular apartments with modular concrete panels as the exterior walls’ solution and different façade configurations (with and without a balcony). A dynamic simulation model of the apartments was constructed in EnergyPlus to compute the annual energy demand and energy consumption for climatization and artificial lighting considering different Portuguese climate zones (Lisbon, Bragança and Faro) and solar orientations (North, East, South and West). Climatization and artificial lighting energy demand was usually higher for the apartment with a balcony. The best energy performances, with an annual energy consumption of 18-23 kWh/m2 of floor area, were obtained for North orientation in Faro and Lisbon for both apartments. South was the worst performing orientation for both apartments. This work is part of the project R2UTechnologies – Modular Systems (02‑C05‑i01.01‑2022.PC644876810‑00000019), funded by the Mobilizing Alliances for Reindustrialization within the Recovery and Resilience Plan (PRR), Resilience Dimension, Investment and Innovation Component.

ABSTRACT. Urban areas account for the majority of global energy consumption and green-house gas emissions, making cities central to achieving climate neutrality. Posi-tive Clean Energy Districts (PCEDs) have emerged as an integrated response, combining energy efficiency, renewable energy generation, system flexibility, and social inclusion at the district scale. Despite growing policy support, critical knowledge gaps persist: PED/PCED implementation requires cross-sectoral col-laboration, multi-level governance, and context-sensitive adaptation, yet lessons remain fragmented and difficult to replicate. This paper synthesizes knowledge from twelve European Lighthouse Cities across six Horizon 2020 and two Hori-zon Europe initiatives. Combining documentary analysis, a structured PED data-base, and semi-structured interviews, the study identifies recurring enabling fac-tors, barriers, and transferable lessons. The findings show that the primary chal-lenge is not technological but institutional: successful PCED development de-pends on governance capacity, financial innovation, stakeholder alignment, and adaptive planning.

ABSTRACT. Cities play a pivotal role in delivering a zero-emission built environment, yet a persistent implementation gap still separates ambitious energy visions from their practical realisation. This paper presents insights from a World Café workshop held during SSPCR 2025 within the framework of two EU-funded projects — i.e., POSEIDON (F-DUT-2022-0340) and WeGenerate (GA101123546). The workshop brought together municipal officers, researchers, and practitioners to explore how Positive Energy Districts (PEDs) and Energy Communities (ECs) can move beyond pilot initiatives and become embedded in mainstream urban planning practice. The discussion was structured around three thematic tables: (i) policies and planning instruments to accelerate PED and EC deployment, including the role of the revised EPBD, district renovation programmes, and feedback mechanisms from local pilots; (ii) methods and standards for collecting, managing, and updating urban open data while addressing issues of data availability, granularity, security, and GDPR compliance; and (iii) governance barriers that hinder or delay climate transition projects, such as multi-level misalignment, political cycle instability, lack of cross-sectoral integration, and limited citizen trust. Across the discussions, participants emphasised the need to contextualise PED definitions within local contexts, institutionalise pilot monitoring processes, strengthen urban data infrastructures for planning and design, and develop multi-level narratives that connect long-term climate goals with everyday urban benefits. The resulting set of proposed “next steps” identifies concrete leverage points—integrating PEDs into statutory planning frameworks, developing data-driven decision-support tools, and fostering transparent public–private collaboration—that can help municipalities and stakeholders systematically bridge the gap between planning and implementation of positive-energy neighbourhoods.

ABSTRACT. The decarbonisation of the built environment is increasingly shaped by locally grounded energy solutions and new forms of citizen participation. In this context, Energy Communities (ECs) have emerged as instruments enabling collective renewable energy generation, sharing, and consumption. Beyond technical or regulatory aspects, ECs raise important questions about local engagement, the embedding of energy initiatives in local territories, and the roles municipalities play in citizen-led, co-promoted or externally initiated initiatives. This paper examines Portuguese municipalities’ engagement with ECs through a nationwide exploratory questionnaire, capturing existing projects, municipal roles, perceived barriers, and expectations for future initiatives. Responses are analysed across three dimensions: who participates, where initiatives are located, and how municipalities engage – by supporting, facilitating, observing, or co-promoting projects. These topologies will be implemented in a Geographic Information System (GIS), allowing a spatial evaluation of the territorial distribution of Energy Communities and municipal engagement patterns across Portuguese municipalities. The results provide a national overview of patterns and variations in municipal engagement, revealing opportunities and challenges for embedding ECs in local territories. These findings can inform policy design, capacity building, and urban energy strategies, supporting inclusive, locally rooted, and zero-carbon transitions in the built environment.

ABSTRACT. The global energy sector is undergoing a profound transformation driven by decentralization, decarbonization, and digitalization, with growing emphasis on distributed energy resources. This shift is motivated by the need to mitigate climate change, reduce energy costs, and promote more equitable access to energy, particularly by addressing energy poverty. In the European Union, strategic concerns related to reducing dependence on international energy markets further reinforce this transition. Within this context, Energy Communities (ECs) are gaining relevance as they reshape how energy is produced, shared, and managed. The Clean Energy for All Europeans package provides the foundational legal framework for ECs across EU member states, notably through the Renewable Energy Directives II and III (RED II and RED III) and the Electricity Market Directive (2019/944). While RED III does not alter the legal definitions established under RED II, it creates a more supportive environment by setting higher renewable energy targets, simplifying licensing procedures, reducing administrative burdens through clearer timelines, and strengthening local engagement, communication, and awareness. Despite their potential to foster a more sustainable, democratic, and inclusive energy system, the expansion of Energy Communities depends on citizens’ acceptance and the behavioral changes required for active participation. This paper aims to analyze the key drivers and barriers affecting the development of Energy Communities, with a particular focus on motivations and administrative obstacles that may hinder or delay their establishment. The study is based on qualitative data collected through interviews with key stakeholders in the energy sector and members of Energy Communities in Portugal.

ABSTRACT. The escalating global demand for energy, coupled with the urgent need to mitigate climate change and promote sustainable agricultural practices, has placed unprecedented pressure on land resources. As the world transitions toward low-carbon energy systems, land has become a critical arena of competition among food production, urban expansion, and renewable energy sources (RES). These dynamics are particularly relevant at the local scale, where land-use decisions reflect both structural conditions and policy frameworks. Moreover, RES are predominantly concentrated in rural areas, where land availability is greater, and renewable energy infrastructures are typically located, while energy consumption is largely concentrated in urban centres. This spatial mismatch between energy production and demand raises important challenges for land-use planning and territorial governance. This study examines the relationship between renewable energy expansion and land use, focusing on a case study of ground-mounted photovoltaic systems and energy crop cultivation in the Lombardy region of northern Italy. Using municipal-level data, the analysis applies a GIS-based multi-criteria spatial approach to map renewable energy production and to develop a balance indicator that captures the spatial distribution of energy production and demand. The outcomes are then used to simulate alternative scenarios of renewable energy expansion across the region. Expected findings offer relevant insights for policymakers seeking to balance renewable energy development with competing land-use demands. Overall, the study emphasizes the importance of incorporating local-level evidence into regional energy strategies and supports the integration of spatial dimensions into renewable energy planning.

ABSTRACT. The present work aims to explore the stepwise integration of renewable and storage systems to reduce diesel consumption and carbon footprint for a standalone residential house in Muscat, Oman. Six scenarios were simulated and analyzed in TRNSYS 18 with Typical Meteorological Year conditions. These include a diesel engine generator set (DEGS) as the baseline, DEGS with a 15-kW photovoltaic (PV) array, DEGS with PV and 25 kWh lithium-ion battery storage, DEGS with PV and a hydrogen subsystem (electrolyzer, compressed storage, and fuel cell), and two cases combining PV (20 kW and 25 kW) with both battery and hydrogen storage. A hierarchical dispatch strategy is applied to all scenarios, with priority given to renewable-based generation. The simulation results show a 24.0% reduction in diesel con-sumption by the inclusion of PV, increasing to 37.7% with battery storage. The hydrogen-only pathway achieved 28.6% reduction, demonstrating a lower storage efficiency when compared to batteries. Combining both stor-age technologies with increased PV capacity (25 kW) achieved the highest diesel reduction of 45.6%, demonstrating the complementary roles of battery and hydrogen storage in integrated renewable energy systems for hot arid climates.

ABSTRACT. Digital Twins (DTs) are increasingly used to bridge design intent and operational performance, yet their deployment across the building lifecycle remains uneven and poorly structured. This study develops a framework for integrating DTs into the Royal Institute of British Architects (RIBA) Plan of Work stages (0–7) to enable measurable performance outcomes and support low-carbon objectives. A systematic literature review was conducted, mapping documented DT applications across all project stages, from early strategic planning to long-term operation. The analysis examined the nature of DT use, stakeholder involvement, data integration, and decision-making processes, informing a framework that captures the evolving role and maturity of DTs throughout the building lifecycle. The proposed framework aligns DT capabilities, data flows, and decision points with specific RIBA stages to support verifiable outcomes. We (i) clarify the distinction between DTs, Building Information Modelling (BIM), and digital shadows; (ii) map enabling technologies to stage-specific tasks; and (iii) define lightweight deliverables and Key Performance Indicators (KPIs) that support measurable performance from Strategic Definition (Stage 0) through In Use (Stage 7). The framework illustrates how early DT prototypes de-risk briefs and concept options; how Stage 3–4 DTs integrate systems and support compliance; how construction-phase DTs enhance logistics, quality assurance, and safety; and how operational DTs enable predictive maintenance, energy flexibility, and post-occupancy verification. The paper concludes with a practical RIBA-DT matrix outlining stage outputs, minimum data requirements, and governance steps to support consistent DT adoption and accelerate the transition to low-carbon buildings and communities.

ABSTRACT. The convergence of distributed renewables, electric mobility, and advanced control is reshaping urban energy districts. This paper presents a scalable framework for residential energy districts integrating GIS-based Ur-ban Building Energy Modeling (UBEM), dynamic simulation of a photovol-taic-integrated battery-hydrogen energy storage system (PV-BHESS), surro-gate-assisted multi-objective optimization, and EV-aware operation within a unified workflow. District electricity demand and EV charging profiles are reconstructed at hourly resolution and coupled with PV, battery, and hydro-gen storage operation. For RES component design, ML surrogates are benchmarked against TRNSYS outputs and embedded in a particle swarm-based multi-objective design optimization (PSMDO) workflow to support sizing across Energy Positivity, LCC, and CO2 mitigation. The framework is further extended to 2050 to assess whether the selected configuration re-mains adequate over the approximate 25-year service life of the main PV-BHESS components, supporting long-term district energy planning. The proposed integration highlights a compact and replicable pathway for future-ready district design.

ABSTRACT. Conservation and management efforts for built cultural heritage are inherently multi-disciplinary. For a holistic view, the strategy of digital transformation for improving efficiency and decision-making should encompass digitisation and simulation processes. This includes as-built data collection and numerical model creation. Focusing on the assessment of a building’s performance, building energy modelling (BEM) allows for both energy efficiency and indoor comfort conditions assessment simulations. To this end, the use of BIM (Building Information Modelling) for BEM creation has been a subject of discussion. Given that BIM offers the advantage of a centralised database with 3D geometric components, integrating spatial and non-graphical data, essential for BEM; although the interaction between the two models remains complex. This article addresses the problem of interoperability between software in the BIM (Autodesk Revit®) and BEM (DOE EnergyPlus™) environments, presenting the main limitations and challenges of transferring information between the different models, considering built heritage complexity. The case study selected is the Monserrate Palace, a masterpiece of Romanticism, due to its importance as Portuguese cultural heritage and part of the Cultural Landscape of Sintra, for which a BIM model was built based on a laser scan survey and enriched with non-geometric information. Data transfer was achieved using the gbXML format and OpenStudio™ Application as an intermediary software. The numerical model was calibrated with in-situ indoor temperature records and the weather file from the closest meteorological IPMA station. Results show that despite the complexity of the case study and the interoperability between models, the fit between the experimental and simulation results was reasonable.

ABSTRACT. This paper examines how the digitalisation of the German energy system and the nationwide smart meter rollout are transforming energy data into an economic asset for a zero carbon built environment. It analyses the emerging ecosystem of passive and active market participants and the diverse data streams generated under different tariff applications and metering configurations. The study develops a structured classification of energy data by source, granularity, temporal resolution and accessibility, and links these categories to specific value-creation mechanisms in the German electricity market. Based on a critical review of existing energy data models and current regulatory and market frameworks, the paper identifies and evaluates data-driven business models, including dynamic and locationally differentiated tariffs, flexibility and demand response services, energy management platforms, and new roles for aggregators and prosumers. The results highlight both the economic potential and the current barriers related to data interoperability, governance, privacy and incentive structures. The paper concludes by outlining a data-to-value framework for the German context that supports smart grids, energy flexibility and advanced energy management in buildings, and indicates how targeted policy and regulatory adjustments could accelerate the deployment of innovative, data-centric business models that facilitate higher shares of renewable energy and contribute to a zero carbon built environment.

ABSTRACT. Accurate short term forecasting of solar irradiance is important for the reliable operation of photovoltaic (PV) systems and power grids. Sky image based forecasting models estimate future irradiance by analyzing clouds near the sun and their short term movement, and they often achieve good performance at very short time horizons. However, prediction accuracy typically degrades rapidly as the forecast horizon becomes longer, especially during rapidly changing cloud conditions. One key reason is that most existing models treat all atmospheric conditions in the same way and do not account for differences in short term predictability.

In practice, solar irradiance predictability depends strongly on recent cloud evolution. Stable atmospheric conditions tend to persist and are easier to predict, while cloud transition periods are associated with rapid changes and higher uncertainty. However, this distinction is rarely modelled in existing sky-image forecasting approaches. To address this limitation, this study proposes a forecasting framework based on the temporal behaviour of the clear sky index (CSI) and cloud coverage (CC). Instead of using instantaneous values, recent CSI and CC observations over a short time window are aggregated to characterise short term atmospheric states. These states are then used as supplementary information to guide sky image based irradiance forecasting.

By accounting for differences in short term atmospheric conditions, the proposed framework reduce forecast error growth at practical short term horizons and improves the robustness and interpretability of solar irradiance predictions. This approach provides a simple and effective way to enhance sky image based forecasting under highly variable cloud conditions.

ABSTRACT. Digital Twins are an engineering tool for buildings that connects design scope with measured operational performance, helping close the design–operation gap by integrating key management domains such as energy efficiency, indoor environmental quality or whole-life carbon footprint. This article synthesizes for a real case scenario how a building twin is defined, structured, and used for decision support. The paper outlines a workflow that starts with a building information model and leads to a simulation-ready representation, with attention to simplification choices and traceability. It describes how monitored data streams, from sensors and automation systems, connect to the digital layer to represent the building state and system behaviour over time. The article discusses the role of data quality, time synchronization, and metadata in enabling reliable comparisons between measured and modelled performance. The twin is framed as a platform that supports operational scenarios, such as energy-saving strategies, comfort tuning, and fault-oriented investigations. Future research directions need to be focused on greater automation and tighter integration of Digital Twin workflows with city-scale, climate-neutral planning and decision-making.

ABSTRACT. Households require energy in the form of electricity and heat, representing 26% of total final energy consumption and 21% of total CO2 emissions in Europe. So-lar technologies can be integrated in the buildings’ envelope to supply renewable electricity and/or heat, being a relevant technology to decarbonize this sector. Photovoltaic-thermal (PVT) collectors are an emerging technology that can gen-erate electricity and heat simultaneously in a single device, generating more useful energy per unit area than conventional solar technologies. Since architectural uni-formity and efficiency can be achieved between the thermal and electric installa-tions, this makes the PVT collectors a well-suited technology for building inte-gration. This article aims to compare the utilization of hybrid photovoltaic-thermal collectors for domestic hot water (DHW) preparation and electricity supply in single-family buildings in Portugal. TRNSYS models were developed to simulate the thermal and electric behaviour of the DHW preparation systems. The annual performance of the PVT systems was determined for a typical meteorological year in Lisbon, Portugal. A techno-economic analysis was conducted for the simulated systems and the performance of the PVT systems was compared with those achieved by conventional DHW preparation systems. In Lisbon, PVT sys-tems outperform conventional DHW systems achieving lower levelized cost of heat. PVT systems with electric resistance as auxiliary heating provide up to 53% of the DHW demand and generate 335 kWh of electricity. PVT systems with heat pump as auxiliary system show a 2 p.p. increase of the coverage of the DHW demand and an 1,2% reduction of the electricity production.

ABSTRACT. To use solar energy effectively for solar PV, solar thermal, or solar power generation, it is essential to measure the solar irradiance at ground level. In practice, a hemispherical pyranometer is commonly installed at a local weather station or directly on site to record solar irradiance on a horizontal plane. This measurement, known as global horizontal irradiance (GHI), provides a general indication of overall solar radiation intensity. However, many solar energy applications involve surfaces that are not horizontal. For these systems, irradiance on tilted or vertical planes is required. Converting GHI into irradiance on a tilted surface, known as global tilted irradiance (GTI), typically follows one of two approaches. Physically based approaches separate GHI into direct and diffuse components (e.g., via Erbs model) and then project these components onto tilted surface using transposition models such as Perez or Hay-Davies. While these methods are widely used for different tilt angles, their accuracy can be limited by fixed coefficients that may not fully represent local climatic conditions. In contrast, data-driven approaches use machine learning techniques to capture non-linear relationships between GHI and GTI under varying weather conditions. These models offer greater flexibility but are often trained for specific tilt angles or orientations, which limits their general applicability. In this study, we investigated the correlation and conversion of GHI to GTI for a 40° south-facing surface using one year data collected in Nottingham, UK. The coefficients of the physical models were recalibrated, while the data-driven models were retrained using local dataset. This enabled a direct comparison between the two approaches. The performance of each approach was evaluated in terms of both computational efficiency and prediction accuracy.

ABSTRACT. Occupancy-aware building control can reduce HVAC and lighting waste, but camera-based edge analytics adds its own electrical load. This paper benchmarks 12 real-time object detectors for meeting-room occupancy counting on Raspberry Pi 5 (8 GB) under headless, passively cooled operation. YOLO8/11/12 nano, small, and medium variants, EfficientDet-Lite0, NanoDet-Plus, and an SSD base-line were deployed using NCNN or TensorFlow Lite with edge-oriented settings. Multiple Raspberry Pi 5 units were run concurrently in a real meeting room across three rounds. The evaluation combines externally measured power, sus-tained throughput, CPU and memory utilisation, and occupancy counting accura-cy against ground truth. Average power varied only from 4.45 to 6.55 W, while sustained throughput ranged from 0.47 to 10.84 FPS. As a result, energy per processed frame ranged from 0.41 J/frame for SSD to more than 11 J/frame for YOLO12m. YOLO models, especially the YOLO11 variants, tracked ground truth most closely during stable occupancy; EfficientDet-Lite0 and NanoDet tended to undercount, and SSD overcounted without counting-specific post-processing. The study shows that edge model selection for smart buildings is a multi-objective decision that must balance counting fidelity, sustained speed, compute headroom, thermal stability, and energy per inference.

ABSTRACT. Building-integrated photovoltaic (BIPV) systems are used to reduce dependence on the grid. While rooftop photovoltaic (RTPV) systems are widely adopted, façade-integrated semi-transparent photovoltaic (STPV) systems offer additional generation potential in cities where rooftop area is limited. Moreover, the extent to which STPV systems complement RTPV in self-consumption and load matching remains unclear. This study evaluates the performance of RTPV and STPV systems, both individually and in combination, in a typical 7-floor residential building in Istanbul, Türkiye. An existing, calibrated EnergyPlus building energy model is used to calculate the heating, cooling, lighting, and equipment loads of three scenarios: (i) RTPV only, (ii) STPV only, and (iii) com-bined RTPV+STPV. Hourly RTPV and STPV generation are calculated using simulations. Key performance indicators (KPIs) include self-consumption rate (SCR), self-sufficiency rate (SSR), and the load match index (LMI). The results show that although STPV cover a larger area than RTPV, they produce about 25% of RTPV generation due to their lower power conversion efficiency (PCE) and lower radiation exposure on vertical surfaces. In the combined scenario (RTPV+STPV), STPV energy production is not used efficiently hourly due to overlapping hourly energy production profiles with RTPV, limiting improve-ments in all KPIs, highlighting the potential importance of storage or demand-side flexibility. Additionally, hourly generation–demand matching is observed during a typical summer week, but is minimal during winter, as heating demand dominates especially during nighttime hours. The findings can inform urban-scale analyses of RTPV and STPV and their combined contribution to energy flexibility.

ABSTRACT. The decarbonization of high-density urban agglomerations relies critically on the mass deployment of Building-Integrated Photovoltaics (BIPV), yet current Integrated Assessment Models (IAMs) often overestimate climate benefits by neglecting lifecycle path dependencies introduced by maintenance cycles and climate-induced degradation. Focusing on Shenzhen—a global manufacturing hub with an active carbon market—this research bridges the "micro-macro" gap through a multi-scale lifecycle carbon management framework. We construct a high-fidelity dynamic Lifecycle Inventory to quantify trade-offs between embodied carbon investments and operational energy yields, explicitly accounting for tropical weathering and component replacement frequencies. A Stackelberg game-theoretic model is then employed to analyze the split-incentive dilemma among stakeholders under Shenzhen’s Emission Trading Scheme, identifying economic tipping points for effective policy alignment. Finally, these empirically derived parameters are used to calibrate supply-side assumptions in the MESSAGEix model, creating a refined input module for urban renewables. The findings reveal that "install-and-forget" practices obscure significant hidden carbon costs, necessitating a strategic pivot from demand-side management to supply-chain circularity. This study positions Shenzhen as a sentinel for the Global South, demonstrating how precise lifecycle governance unlocks the true mitigation potential of megacities.

ABSTRACT. Cooking generates short, intense indoor pollution events that can dominate expo-sure, especially in open-plan spaces where emissions migrate into adjacent occu-pied areas. This paper combines a focused review with a field case study to as-sess event-triggered kitchen ventilation using vision-based appliance-use infer-ence. The review highlights three main issues: capture efficiency, rather than air-flow alone, governs source control; sensor-only demand control may respond too late to fast peaks; and current standards permit demand operation but do not spec-ify robust real-time control signals. A kitchen connected directly to an office area was instrumented with CO2 and PM2.5 sensors, temperature probes and fan-power monitoring. A Faster R-CNN model detected active stove/hob, oven and toaster use and translated detections into a count-based signal for extractor con-trol. The detector achieved F1 scores of 0.892, 0.935 and 0.946 for stove, oven and toaster, respectively. Compared with constant-speed mechanical extraction, the vision-modulated strategy reduced kitchen peak PM2.5 from 898 to 742 ug/m3 and final kitchen PM2.5 from 112 to 79 ug/m3, while final office PM2.5 fell from 66 to 47 ug/m3. These improvements were achieved with only a 3.7% increase in fan energy and a 0.8% increase in daily heating demand relative to the constant-speed case. The findings support hybrid, source-aware ventilation that uses vi-sion as a leading indicator and pollutant sensing as feedback.

ABSTRACT. The demand for indoor cooling systems is growing steadily, driven by an increase in the frequency of heatwaves associated with global warming, economic growth, and the greater distribution of electricity, particularly in developing countries. As energy use for indoor cooling continues to expand, numerous building design methods and technological solutions have emerged to address and limit this trend. Some of the most promising solutions are related to the implementation of dynamic building elements, which can adapt their behaviour to different climatic loads. Despite the clear advantages of these systems, their development and application have still not received a wide implementation outside the scientific environment. This study assesses the thermal behaviour of an innovative Dynamic Thermal Insulation System (DTIS) specifically designed for façades consisting of a double leaf brick wall, with an air cavity, commonly used in southern Europe during the 1970’ and 1980’ decades, which are now being retrofitted with external thermal insulation systems to become more energy efficient. The DTIS allows two different thermal states of the façade: an insulated state, during the heating season, and a conductive state, whenever there is a risk of indoor overheating. It is based on bottom and top openings in the wall, allowing air circulation from the outside environment to the air gap, enhancing heat transfer under specific environmental conditions: in the insulated state the openings are closed and heat transfer is reduced, and in the conductive state the openings are open to increase heat flux and decrease the risk of overheating. The experimental campaign, carried out in a climatic chamber, assessed heat transfer through a double leaf wall with DTIS considering three configurations: openings sealed (insulated state), air gap naturally ventilated (conductive state), and air gap mechanically ventilated (conductive state). Air temperature (indoor, outdoor and air gap), surface temperature on different layers of the wall and heat flux were measured under dynamic conditions to assess heat transfer without and with DTIS to assess its effectiveness. The results showed that the decrease of temperature in the indoor environment was approximately 50% faster when the DTIS was used. Higher decrease was observed when mechanical ventilation was used, compared to natural ventilation of the air gap. It was also observed that the position of the fans in the lower opening produced better results than in the upper position.

ABSTRACT. Responsive smart windows are increasingly recognized as an effective strategy for reducing building energy consumption and improving indoor environmental quality. However, existing approaches are often static, case-specific, with limited flexibility for iterative and lack accessible workflows for iterative, time-dependent control design. This limits designers’ ability to determine appropriate transmittance settings across varying climatic and temporal conditions and to translate simulation results into actionable control strategies. This study presents a modular Rhino–Grasshopper-based platform for parametric simulation and control-oriented evaluation of smart window performance. The workflow integrates Honeybee with EnergyPlus/OpenStudio to couple energy and daylight simulations within a unified environment. A structured pipeline enables reproducible simulations, flexible parameter definition, and remote execution, supporting systematic scenario comparison. Smart window transmittance is treated as a continuous variable, and optimal values are identified across different time periods. A pilot case study under Beijing climatic conditions demonstrates time-dependent optimal transmittance values (0, 0.2, and 0.5), revealing a clear shift in control requirements driven by solar conditions. These results highlight the necessity of adaptive control strategies and demonstrate the potential of the workflow to support decision-making in both smart window selection and control strategy design. By linking parametric modelling, performance simulation, and control-oriented outputs, the proposed platform provides a scalable and designer-friendly approach for performance-driven façade design in zero-carbon buildings.

ABSTRACT. The construction industry alone is responsible for approximately 40% of global carbon emissions and represents a critical opportunity to advance towards global net-zero targets. Within construction, design for disassembly (DfD) emerges as a potential strategy for applying circular economy (CE) principles through extending materials’ life cycles and transforming buildings into material banks. Despite the urgency of achieving net-zero, DfD accounts for only 1% of construction projects. Within the current research into DfD, stakeholder management is amongst the least studied aspects despite ranking amongst the top 3 barriers to DfD implementation. This paper addresses this research gap by investigating stakeholder dynamics between architects and project managers, chosen specifically because of their respective critical influence on design and cost factors. It aims to investigate key stakeholder value gaps between design-driven and cost-driven decision frameworks across DfD projects. To ensure research depth and specificity, this study adopts a mixed-method approach, collecting data through a questionnaire using a multi-criteria decision analysis framework comprised of a design value matrix for scenario-based questions, analytical hierarchy process for ranking criteria, and qualitative interviews for select respondents. While both stakeholder groups demonstrated a willingness to integrate DfD principles, emerging value gaps were impacted by different perceptions on initial cost vs. residual value, material purity vs. procurement ease, technical complexity vs. logistical stress, and long-term carbon capture vs. shortterm project risk. This paper contributes to further development of decision frameworks necessary to the success of DfD projects by identifying critical value gaps between cost and design driven stakeholders.

ABSTRACT. A new thermoregulative building façade is presented that integrates a copper nanofluid, whose thermal properties prove to be auspicious in maintaining thermal comfort. The wall consists of two reservoirs, one inside and one outside. During the day, the fluid will be in the outer reservoir in the cold season and in the inner reservoir in the hot season, the opposite happening at night. Two modules were built, one with a masonry wall and the other with a water wall. The dynamic thermal behaviour of the modules was simulated in ANSYS Fluent under summer and winter conditions for a full day, validating the model by comparing the results with the temperatures obtained experimentally in summer. The experimental measurements, carried out over 4 days, indicated that the module with the water wall exceeded 28 °C in 124 of the 577 temperature measurements, while the module with the masonry wall only overheated in 33 measurements. Despite the discrepancies between the simulated temperatures and the temperatures obtained experimentally, it was determined that the model can be used for a preliminary comparative analysis.

ABSTRACT. Enhancing building energy performance requires a comprehensive understanding of the thermal exchanges across the building envelope. Window systems, in particular, represent a critical source of heat losses, solar gains, and thermal bridging. Although ISO 10077-2 provides procedures for assessing the thermal performance of window frames, conventional U-factor evaluations frequently neglect the additional thermal bridges that arise at window-to-wall junctions, especially at sills, lintels, auxiliary structural components, and flashing interfaces. These localized heat-flow irregularities can substantially influence the overall thermal behaviour of the installation. To address this gap, the present study examines the thermal performance of an innovative thermal ring frame designed to refine heat transfer across the window-to-wall interface. Designed as monoblock window frame section, alongside the perimeter of the wall opening, it also aims to standardize the dimensions of the windows on the facade, eliminating the need for sealing between the masonry and the frame, and preventing performance loss due to installation errors. A finite-element model was developed in COMSOL Multiphysics to simulate steady-state conductive heat transfer through a representative window assembly consisting of a double-glazed unit housed within an aluminium casement frame with a thermal break. Model validation was achieved by comparing the calculated linear thermal transmittance (Ψ-values) with reference values specified in ISO 10077-2.

ABSTRACT. Rooftop photovoltaics (PV) can reduce electricity bills and carbon emissions in social housing. However, council-owned deployment creates a split-benefit challenge: the local authority funds or coordinates the asset, while tenants capture a substantial share of the bill-saving benefit. This paper evaluates a shared-benefit business model for a representative UK council-housing dwelling using 16 rooftop PV scenarios over a 25-year modelling horizon. The scenarios examine the effects of grant support, sell-to-tenant tariffs, Smart Export Guarantee revenue, battery storage, occupancy profile and finance cost. The results indicate that the strongest shared-benefit outcomes arise in grant-supported, PV-only cases with moderate sell-to-tenant tariffs. Battery storage increases onsite PV utilisation, but it weakens local-authority cash flow under the tested capital and replacement-cost assumptions. Full-finance cases without grant support struggle to recover costs without reducing or eliminating tenant savings. The study demonstrates that council-housing PV should be designed as an integrated tariff-and-finance model that jointly evaluates local-authority investment recovery and tenant affordability

ABSTRACT. The transition to renewable energy sources imposes challenges in the energy sector. Using available energy flexibility through energy management systems offers a promising solution to address these issues. This study proposes and evaluates a non-intrusive monitoring method for Electric Water Heaters (EWH) temperature monitoring, removing the need for expensive or intrusive tank temperature sensors. Instead, a temperature-based method is developed using energy consumption and water usage patterns. Integrated within an energy management system, the method allows to achieve comparable results to those reported in the literature, particularly in terms of reducing user costs while maintaining comfort. The proposed method is validated through real-world deployment within the IANOS H2020 project, with results benchmarked against an intrusive monitoring technique. The findings show that the non-intrusive method achieves an average error of 3.20 °C, while offering greater adaptability across different EWH models, at the expense of insignificant discomfort for the end-user.

ABSTRACT. The increasing variability of electricity prices and the growing adoption of distributed photovoltaic systems necessitate advanced optimization strategies that can effectively coordinate local generation, storage, and consumption. This study presents a smart energy management model for a grid‑tied photovoltaic installation with battery storage, applied to a consumer in Valencia. A genetic algorithm is used to optimize demand response actions, battery charging and discharging strategies, and energy exchanges with the grid, seeking to minimize operational costs while maximizing self‑consumption. The methodology incorporates real consumption and market price, enabling the system to adapt dynamically to daily and seasonal conditions. Particular attention is given to situations in which the photovoltaic system generates a significant surplus of energy; in these cases, the model evaluates the potential benefits of integrating the user into an energy community, assessing how collective self-consumption and shared storage can enhance economic and environmental performance. The results highlight the capacity of evolutionary optimization to coordinate flexible demand, distributed storage, and renewable generation, offering a robust pathway to improve energy autonomy and contribute to more resilient community‑based energy models.

ABSTRACT. High renewable energy penetration has intensified real-time supply-demand mismatches, making demand-side flexibility resources (DFRs) increasingly important for renewable energy integration and system balance. With a focus on electricity systems at the community scale, this review develops a unified framework for examining DFRs across four interconnected dimensions: definition, incentives, planning, and scheduling, drawing on a systematic literature review and an empirical analysis of evidence from China, the United States, and the United Kingdom. The review identifies distributed photovoltaics, battery energy storage systems, electric vehicles, and flexible loads as the principal DFR categories, and defines aggregated flexibility as the capability of coordinated resources to produce feasible deviations in net load from a baseline trajectory under operating constraints and uncertainties. It further identifies 13 incentive mechanisms spanning deployment-oriented and participation-oriented categories, and reveals marked cross-country differences in institutional structure and market maturity. Planning studies are predominantly centred on techno-economic, renewable integration, and carbon reduction objectives, and mainly rely on optimization and simulation methods under technical, uncertainty, and price constraints. Scheduling studies are more directly oriented toward flexibility service provision, economic performance, and load shaping, and are mainly constrained by device, market, grid, and user factors. Optimization and model predictive control remain the dominant approaches, while learning-based and game-theoretic methods are attracting growing attention. Four major research gaps are identified: the lack of a standardized flexibility evaluation framework, insufficient integration of multi-stakeholder coordination into analytical models, limited cross-scale coupling, and oversimplified representations of market and regulatory environments.

ABSTRACT. This study evaluates the real-world performance of photovoltaic (PV) and battery systems integrated into 65 homes built under the Swansea Standard. This is a whole-house approach combining high-performance fabric, ground source heat pumps, and renewable energy technologies. The homes, located across four developments in Swansea in South Wales, were monitored for up to four years to assess self-sufficiency, self-consumption and operational energy, cost and carbon savings compared to similar homes. Each dwelling incorporates a building-integrated PV system (3.8-4.6 kWp) and a 13.5 kWh lithium-ion battery. Monitoring data reveal that PV genera-tion and storage contribute significantly to reducing grid dependency: flats achieved an average of 60% energy self-sufficiency, bungalows exceeded 63%, and houses averaged 39%. Direct PV use met 22–31% of total con-sumption, while battery stored energy contributed a further 17–35%, high-lighting the critical role of storage in optimising self consumption. Despite battery losses averaging 16%, the systems consistently improved energy re-silience and affordability. Annual grid energy imports were lower by 71-87% and energy cost was lower by 29-69% compared with Welsh benchmarks for similar homes. Operational carbon emissions were near-net-zero for flats and bungalows considering emissions avoided due to electricity export. The findings demonstrate that PV-battery integration in social housing can deliver substantial carbon and cost benefits when combined with fabric-first design and heat pumps. However, performance optimisation particularly in battery scheduling and demand matching remains essential to maximise fi-nancial and environmental gains.

ABSTRACT. Abstract. The integration of distributed photovoltaics (DPV) and electric vehicles (EVs) inherently exacerbates grid volatility due to severe spatio-temporal mismatches. Furthermore, conventional price-driven Independent Economic Optimization (IEO) for Vehicle-to-Grid (V2G) often triggers detrimental coincident charging, creating severe artificial rebound peaks during off-peak hours. This paper proposes an incentive-compatible, two-stage optimization framework enabling Cross-Zonal Flexibility Sharing (CZFS) among heterogeneous energy districts. Stage 1 establishes an absolute minimum-cost baseline via IEO. Stage 2 minimizes aggregated net-load variance subject to a strict economic tolerance constraint (e.g., 0.5%), ensuring no zone sacrifices profitability beyond an acceptable margin. A multi-scenario case study on the HKUST campus demonstrates a profound asymmetric leverage effect. For a negligible expected campus-wide concession of 8.35 HKD/day, the CZFS activates a spatio-temporal flexibility transfer, yielding a 29.7% reduction in residential load variance compared to IEO and cutting EV charging costs by up to 31.7% relative to uncoordinated charging.

ABSTRACT. The rapid deployment of photovoltaic (PV) systems in buildings highlights the need for carbon-aware operation, as electricity-related carbon emissions vary with grid intensity. This study proposes a probabilistic forecasting framework to identify high-carbon hours in PV-integrated buildings. An Attention-based BiLSTM model is developed for 1-hour-ahead net load prediction, using historical load, PV generation, meteorological data, and temporal features. Predicted net load is combined with real-time grid carbon intensity to estimate building carbon exposure. High-carbon hours are detected via percentile thresholds and probabilistic prediction intervals. Evaluation on a full-year dataset from eight residential buildings at HKUST shows that the proposed model outperforms baseline Persistence and standard BiLSTM models (RMSE: 27.715 kWh, MAPE: 21.167%, R²: 0.797). The probabilistic High-CI (95%) strategy achieves high recall (0.927–0.957), enabling proactive identification of carbon-critical periods for risk-averse, low-disruption interventions, while point prediction provides complementary precision for high-cost operational actions. This clear trade-off highlights the framework’s flexibility in supporting varied demand-side strategies to reduce carbon exposure, integrating forecasting uncertainty into building-level carbon management for PV-rich urban environments.

ABSTRACT. Energy poverty is traditionally addressed through direct subsidies, representing sunk costs for public administrations. This study evaluates the transition towards solidarity-based Renewable Energy Communities (RECs) as a sustainable asset-based solution. Using real hourly data from 43 vulnerable households in Valencia, we developed a techno-economic optimization model to determine the optimal configuration and beneficiary selection criteria.

Statistical analysis reveals that annual energy demand is the sole reliable predictor of financial return (R2>83%). Crucially, the study identifies a high profitability threshold for PV-only systems (>1,717 kWh/year), limiting their efficiency for low-consumption households. Integrating battery storage (BESS) reduces this threshold to 846 kWh/year, expanding the range of economically viable profiles by 50%. We conclude that storage is essential to optimize limited public resources, enabling more vulnerable households to transition from palliative subsidies to sustainable assets.

ABSTRACT. Parabolic trough collectors (PTCs) represent the most mature and widely deployed technology in concentrated solar power systems. As the key component of PTCs, parabolic trough solar receivers (PTRs) enable high outlet temperatures required for industrial process heat; however, elevated operating temperatures exacerbate radiative heat losses. In PTRs, the absorber tube plays a major role. To overcome this limitation, based on the characteristic of uneven distribution of solar irradiance around the absorber tube, this study proposes an innovative Metal–transparent conductive oxide (TCO) –SiO₂ (MTS) multilayer film, and applying MTS film coating onto the upper part of the glass envelope. The MTS film achieves the combination of advantages of metal films and TCO films, it offers high infrared reflectance and maintains high solar transmittance. The MTS structure achieves a solar-weighted transmittance of 64.01% in the spectrum of solar radiation and an infrared reflectance of 89.91%. A spectral-based thermal model was developed to evaluate its performance comprehensively. Results demonstrated that, compared with conventional PTRs, the relative thermal loss reductions of the MTS-coated PTRs reached 27.36%, 29.35%, and 30.76% at absorber temperatures of 400 °C, 500 °C, and 600 °C, respectively. Correspondingly, collector efficiency increases by 1.23%, 3.51%, and 7.55% under inlet temperatures of 400 °C, 500 °C, and 600 °C, respectively. Comparative analysis further confirms the superior solar thermal application of the MTS film over standalone metal or TCO coatings, demonstrating its potential to enhance high-temperature PTC performance for industrial solar heat applications.

ABSTRACT. This paper presents the design methodology, outcomes, and lessons learned from the Voldsløkka development in Oslo, one of the six demonstration sites of the ARV Horizon 2020 project aiming to accelerate Climate Positive Circular Com-munities (CPCCs). The Voldsløkka development comprises Oslo’s first plus-energy secondary school, a cultural center located in a listed industrial building that has been adaptively reused and a future plus‑energy sports hall, developed within an ambitious environmental, social, and regulatory framework. In this pa-per we document the integrated design process of the school and cultural centre from early urban planning to detailed design and construction, emphasizing the importance of coordinated stakeholder engagement, iterative scenario analyses, and regulatory clarity. Key technical innovations include façade‑integrated photo-voltaic systems, an emissions‑guided design process, and a nature‑based storm-water management system aligned with Oslo’s blue–green strategies. Circular renovation strategies - particularly the reuse and upgrading of existing building elements - demonstrated notable reductions in embodied emissions, though herit-age constraints and limited local reuse pathways posed challenges. The project il-lustrates the complexities of balancing energy ambitions, cultural heritage preser-vation, and multifunctional use in an urban context. Lessons learned highlight the value of long‑term design team continuity, the need for early alignment between municipal planning and project‑level decisions, and the benefits of combining BIM, LCA and participatory processes to support evidence‑based deci-sion‑making. User surveys revealed varying perceptions of architectural quality, underscoring the importance of iterative feedback loops in future CPCC devel-opments. The findings contribute practical insights for municipalities, developers, and practitioners seeking to scale up climate‑positive and circular solutions in ur-ban regeneration projects.

ABSTRACT. Seaweed-derived biopolymers offer a sustainable and biodegradable alternative for façade protection, supporting circular and low-carbon construction strategies. This study investigates an agar-based biopolymer gel, plasticized with glycerin, as a sacrificial anti-graffiti coating for hydraulic lime mortar substrates. To enhance moisture resistance, formulations incorporating a hydrophobic beeswax additive were evaluated. The coatings were characterized through visual assessment, contact angle measurements, and Fourier-transform infrared spectroscopy (FTIR). Results indicated that the biofilms formed continuous, flexible layers that successfully adapted to the porous morphology of the mortar substrate. Contact angle measurements (c≈68°) and ATR-FTIR revealed a predominantly hydrophilic behavior due to the matrix's hydroxyl groups, and the incorporation of beeswax showed limited effectiveness in reducing moisture adsorption. Despite these hygroscopic challenges, the biofilm exhibited excellent anti-graffiti performance. It functioned as an effective sacrificial barrier, preventing direct pigment penetration into the substrate and enabling simplified removal via a peel-off cleaning process. These findings highlight the potential of seaweed-derived bio-films as environmentally compatible protection systems for both contemporary and heritage-sensitive architecture. Future research should focus on enhancing environmental durability and hydrophobicity, as well as integrating multifunctional additives, such as photocatalytic particles, to provide self-cleaning properties.

ABSTRACT. Building integrated photovoltaics (BIPV) and building applied photovoltaics (BAPV) represent two distinct strategies for incorporating solar energy into building envelopes. This study compares their environmental performance through a cradle-to-grave life cycle assessment (LCA) of cadmium telluride (CdTe) systems installed on the south-facing glass façade in Borlänge, Swe-den (60.5°N). The assessment was performed using SimaPro 9.5 and the En-vironmental Footprint (EF) 3.1 method. Two functional units are defined to provide a comprehensive analysis: (1) 1 kWh of electricity generated over a 30-year lifetime to compare BIPV and BAPV from an energy perspective, and (2) 1 m² of south-facing façade to evaluate BIPV (comparing "net" and "gross" configurations) from a building perspective. Results indicate that BIPV achieves a climate change impact of 28 g CO₂ eq/kWh, representing a 38% reduction compared to BAPV (45 g CO₂ eq/kWh). From a building per-spective, the gross BIPV configuration yields 114 kg CO₂ eq/m², while the net configuration yields 69 kg CO₂ eq/m², a 40% decrease attributable to al-locating façade materials to the building function. These results show that BIPV façades have lower environmental impacts than BAPV in Nordic cli-mates when their dual function is considered. They also show that allocation choices are important in LCA and support using BIPV in façade renovations, where it can replace building materials.

ABSTRACT. This work aims to demonstrate how the integration of innovative digital technologies can support building rehabilitation by enabling the assessment of the energy performance and thermal comfort of a classroom through dynamic simulation. The work focuses on analysing the influence of different retrofit measures on the building envelope - thickness of the thermal insulation, features of the glazed openings and solar absorption coefficient of the exterior wall - through the evaluation of their impact on energy consumption and thermal comfort. The developed methodology combines an integrated workflow of 3D scanning, BIM modelling and hygrothermal simulation. Polycam was used for 3D scanning and Autodesk Revit for constructing the geometric model, which is subsequently imported into WUFI Plus where the influence of the construction solutions is simulated. Three sets of simulations are performed, each assessing the isolated effect of one parameter, followed by the analysis of two integrated improvement combinations. The results show that increasing the insulation thickness has a limited impact on energy consumption, whereas solar control prove to be decisive. Reducing the solar factor of the glazed opening is the most influential parameter, particularly given the high cooling demand in the Portuguese climate. The thermal comfort analysis confirms this trend, indicating that overheating, derived primarily from the solar factor of the glazing, is the main source of discomfort and that controlling solar radiation is the most effective strategy to mitigate it. It is concluded that interventions must be carefully adapted to the climatic context, constructive characteristics and patterns of use. The methodology presented proves to be effective for the evaluation of solutions and constitutes a useful tool to support decision making in the context of energy efficient rehabilitation.

ABSTRACT. Achieving high levels of airtightness is a critical prerequisite for the energy efficiency, durability, and indoor environmental quality of contemporary timber buildings. As timber and mass-timber construction systems such as cross-laminated timber, timber frame, and structural insulated panels become increasingly prevalent in low-carbon building strategies, ensuring reliable airtightness at the building envelope level remains a major design and construction challenge. This paper presents a comprehensive analysis of airtightness performance in timber building envelopes, synthesising findings from international literature, standards, and documented case studies with a specific focus on construction detailing and execution quality. Particular attention is given to the role of junctions, penetrations, and material interfaces, which consistently dominate air leakage behaviour in timber structures due to the hygroscopic nature of wood and its sensitivity to moisture-induced dimensional changes. Standardised measurement methods, primarily blower door testing according to ISO 9972, are reviewed alongside complementary diagnostic techniques such as infrared thermography, acoustic investigation, and smoke testing, highlighting their relevance for identifying concealed leakage paths during construction. The paper further discusses best-practice construction principles, including continuous air-barrier planning, movement-tolerant sealing strategies, and stepwise verification during construction. The findings underline that airtightness should be treated as an integrated design and construction outcome rather than a material property, and that rigorous detailing and quality control are essential for enabling timber buildings to meet high-performance and net-zero carbon targets.

ABSTRACT. The decarbonization of the European building stock requires the inclusion of historic buildings within energy transition strategies, despite architectural constraints and regulatory exemptions. This study investigates five retrofit scenarios applied to Villa Farnesina, a Renaissance historic building in Rome. A calibrated dynamic simulation model, developed according to UNI EN ISO 52016-1 and validated following ASHRAE Guideline 14, was used to assess energy, environmental, and economic performance. The analyzed scenarios range from shallow retrofit (condensing boiler replacement) to deep electrification strategies based on air-to-water and water-to-water heat pumps, including photovoltaic integration and a decentralized water-loop heat pump (WLHP) system. Results show that boiler replacement achieves moderate reductions in primary energy and CO₂ emissions (21%), while elec-trification scenarios enable substantial improvements, with reductions up to 81% in primary energy and 79% in emissions. However, heritage constraints significantly limit the applicability of conventional solutions, in this case WLHP configuration allows full-building heating and cooling with minimal invasiveness. From an economic perspective, deep retrofit scenarios remain unprofitable under standard market conditions and become viable only with national incentives such as Conto Termico 3.0. The results highlight a struc-tural misalignment between private economic returns and public environ-mental benefits, emphasizing the need for targeted policy support. Future work will investigate heritage-compatible passive measures and integrate Life Cycle Assessment to evaluate embodied emissions and environmental pay-back.

ABSTRACT. This research investigates the cooling potential of Pavement Solar Collector (PSC) systems in reducing air and surface temperatures within urban street canyons. A coupled computational modelling approach in ANSYS Fluent was used to simulate the heat transfer between solid pavement and fluid domains. The numerical model was validated through laboratory experiments using a prototype asphalt slab with embedded copper pipes, showing strong agreement between simulated and experimental temperature profiles. The study evaluated the impact of varying inlet water flow velocities (0.1 m/s to 2.0 m/s) and temperatures (15 °C to 25 °C) on cooling performance. Results indicated that the PSC system significantly reduces pavement surface temperatures by up to 20 °C in unshaded areas and lowers near-ground building wall temperatures by approximately 10 °C to 15 °C. The cooling effect extends to the surrounding air, with temperature reductions of 5 °C to 10 °C observed at heights below 1.5 meters. Furthermore, the analysis reveals that lower inlet water velocities result in higher outlet temperature increments. The maximum heat transfer rate was achieved at a turbulent flow velocity of 0.25 m/s. However, laminar flow absorbed more heat due to longer contact time. Lower inlet water temperatures also enhanced heat dissipation, with 15 °C water removing 14.2% more heat than 25 °C water. Ultimately, the findings confirm that implementing PSC systems can improve pedestrian thermal comfort, protect vehicle tires from extreme heat, and reduce building cooling energy demands in urban environments.

ABSTRACT. Domestic space heating and hot water accounted for 77.6% of final household energy consumption in the EU in 2023, with the majority supplied by fossil fuels. A technology capable of meeting this demand without the use of fossil fuels, and with reduced electrical input, would therefore offer significant potential to cut CO₂ emissions and support the achievement of the Paris Climate Accord 2050 net zero target. This review will investigate the current state of vapour absorption and related technologies with a mind to demonstrate the underlying principles of a novel variation of the vapour absorption heat pump cycle, in which latent heat can be extracted from outdoor air under winter ambient conditions and subsequently released as sensible heat for space heating, while requiring only minimal electrical input. This preliminary work is intended to be further developed towards the demonstration of a prototype heat pump that operates using energy from outdoor ambient air and can deliver heat at temperatures suitable for domestic space heating.

ABSTRACT. Flour milling facilities have been the cornerstone of agricultural processing for centuries. Their buildings containing them conserve unique design requirements worldwide. Many buildings for milling industry, included related storage and warehouse areas across Italy are tall and mostly featured by wide facades that mark the industrial landscape. The BIPV facades systems ensure nowadays high solar energy production without using ground level and they can improve aesthetically the grey-often industrial or port landscapes. This study analyses the Italian building stock of milling industry in Italy by evaluating the energy unexpected potential coming from their facades. With the aim of the reuse and sustainable development of existing silos it is crucial to add the façade’s energy value to their urban planning and architectural value as integral elements of their areas. Moreover, this study provides different solar and structural design solutions by involving last innovative buildings integrated solar technologies and various possibility offered by AI support devices to optimize the structural design process. This national study will define the basis for further researches towards a worldwide mapping of this energy potential, and it will trace new directions for buildings renovation in term of energy policies and new infrastructures devoted to a community service.

ABSTRACT. This article presents a case study on phased renewable energy deployment in mining regions, examining how community-scale solar investments and evidence-based feedback mechanisms informed the internal energy transition strategy of a mining company in Armenia. Following an initial deployment of standardized solar systems, a second implementation phase extended installations to a total of 273 rooftop solar photovoltaic (PV) systems and 227 solar water heaters across adjacent communities, including households with severely degraded roofs and limited energy infrastructure. System performance, operational reliability, and user feedback were systematically monitored under real-world conditions, generating robust empirical data on energy yield, maintenance needs, and social acceptance in challenging built environments. In parallel—but not physically integrated—the mining company initiated its own decarbonization pathway, using aggregated performance data and structured stakeholder feedback from community deployments to support investment decisions for a pilot on-site solar PV project consisting of two 2.5 MW plants (5 MW total) dedicated to self-consumption. The study demonstrates how responsibly implemented community renewable projects can reduce uncertainty, build institutional confidence, and strengthen the social and technical basis for industrial-scale renewable investments. The findings highlight that parallel progress in community energy access and corporate energy transition can jointly contribute to zero-emission built environments, improved resilience, and scalable decarbonization pathways in resource-intensive regions, with long-term expansion potential reaching 100 MW.

ABSTRACT. This article assesses the sustainability of energy infrastructure for electric vehicles (EVs) in Colombia, using a system dynamics framework. The study aims to identify the key environmental, social, economic, and infrastructural factors shaping the deployment of EV-related energy systems and their contribution to CO₂ emissions reduction. The methodology integrates time-series analysis with stock-and-flow modelling, using annual data for the period 1990-2020, complemented by variables representing the urban infrastructure and electricity demand patterns. The results reveal a positive short-term relationship between energy intensity and the expansion of EV infrastructure, suggesting that improvements in energy efficiency within the built environment play a critical role in accelerating sustainable electrification pathways. Furthermore, three dominant feedback mechanisms are identified: (i) a reinforcing loop between efficiency investments and EV infrastructure expansion, (ii) a balancing loop linking CO₂ emissions and policy responses, and (iii) a reinforcing loop connecting economic growth, urban development, and environmental pressures. These interactions highlight the dynamic interdependencies between the urban infrastructure, transportation system, and policy interventions. The findings indicate that isolated policy measures targeting either transport or buildings are insufficient to sustain long-term electrification pathways. Instead, integrated policy frameworks that simultaneously promote clean mobility, enhance energy efficiency in the built environment, and stimulate investment in sustainable energy infrastructure are required. The study concludes that public-private cooperation is essential to strengthen these dynamics and ensure a resilient and equitable electric mobility transition in Colombia.

ABSTRACT. Positive Energy Districts (PEDs) are increasingly recognised as a key instrument for accelerating Europe’s clean energy transition and decarbonisation, in line with the European Green Deal and the Sustainable Development Goals. Moving beyond building-scale approaches such as Nearly Zero Energy Buildings, PEDs address the district level by integrating energy efficiency, renewable energy production, and energy flexibility, while embedding social innovation and citizen participation. Within this framework, the renovation of the existing building stock emerges as a critical enabler for the development and functioning of energy communities. This paper investigates key aspects in PED implementation, highlighting the potential of renovation strategies and energy communities in the context of PEDs, through a systematic literature review and case analysis, to identify approaches and experiences connecting building renovation, collective energy systems, and community-based governance. The analysis focuses on how renovation interventions at the building and district scale support energy efficiency improvements, facilitate the integration and sharing of renewable energy sources, and enhance energy flexibility through demand-side management and storage. The inherent technical and social dimensions of PED implementation position renovation and energy communities not only as a physical upgrade but also as a catalyst for social innovation in governance and business models. The results underline the importance of coupling renovation-driven energy performance improvements with community-based approaches to support the scalability and replicability of Positive Energy Districts.

ABSTRACT. Residential overheating is increasingly recognised as a critical risk under current and future climate conditions, yet the influence of internal spatial configuration on overheating performance remains poorly understood. This paper investigates how internal layout and built form affect summertime overheating in typical UK mid-terrace dwellings. Dynamic thermal simulations are conducted on two representative dwelling archetypes (a pre-1919 and a post-1919 mid-terrace) over a short period that includes an extreme heatwave event. The analysis focuses on the principal living room, a key daytime occupied space. For each dwelling, two internal configurations are assessed: an original layout with a single internal door and external window, and an open-plan configuration created by opening the living room into the adjacent dining room, increasing internal connectivity and natural ventilation potential. Overheating outcomes are compared across dwelling types to quantify the influence of built form, and within each dwelling to isolate the effect of internal configuration. Simulations are further repeated for both dwellings following a deep retrofit package meeting current building-regulation thermal standards, allowing the interaction between fabric performance and internal layout to be examined. The results demonstrate that internal configuration can significantly alter overheating risk and that retrofit measures do not uniformly reduce overheating across layouts. The findings have implications for climate-resilient retrofit design and the development of scalable, data-driven methods to assess overheating risk. This study also provides an initial exploration of the concept of overheating archetypes in cold and temperate climates, an area that has received limited attention to date.

ABSTRACT. Deep learning (DL)-based surrogate models in computational fluid dynamics (CFD) have gained significant attention due to their capacity to accelerate flow field prediction through model inference while minimizing the computational resource requirements for CFD simulations. However, conventional supervised DL approaches require large amounts of high-quality data for training and are limited by restricted generalization under conditions outside the training distribution, confining their application to specific cases. While the robust reasoning capabilities of Transformer-based large language models (LLMs) suggest the potential for application in the fluid dynamics, these models are primarily rooted in language tasks; therefore, attempts to apply them to CFD remain in the early stages. This study introduces the FlowLanguage framework, which is designed to learn flow physics using the open-source LLM Qwen3 model as a backbone. The FlowLanguage consists of two primary stages. The first stage involves self-supervised pre-training to internalize the grammar of physics, which captures spatial continuity and causality of flow. In the subsequent stage, physics-informed fine-tuning is applied to reinforce physically consistent predictions by incorporating physics-based penalty term. To evaluate this framework, flow field was predicted using a 2D isothermal indoor airflow benchmark case. The results show the enhanced generalization ability of FlowLanguage, characterized by high data efficiency with limited training data and reasonable extrapolation performance. These findings indicate that self-supervised LLM pre-training internalizes transferable flow representations for indoor airflow modeling in the built environment. FlowLanguage enables rapid evaluation of airflow-control strategies, supporting digital workflows that improve indoor environmental quality while reducing HVAC design iteration time, which facilitates performance-driven design toward zero-emission buildings.

ABSTRACT. Urban street regreening is increasingly recognised as an important strategy for climate adaptation and for improving the quality of the environment in dense ur-ban areas. This paper presents a pilot case from a particular street in Gdańsk, Po-land, aimed at developing a data-driven framework to support street regreening decisions under real planning constraints. The study combines three methodolog-ical components. First, on-site environmental conditions are monitored using fixed low-cost sensor stations measuring selected air quality, microclimatic, and wind parameters to identify pollution hotspots, strong wind exposure, and urban heat island dynamics. Second, UAV-based photographs combined with a YOLOv8 image classification workflow are used to detect pedestrian presence and generate heat maps of spatial activity patterns. Third, GIS-based 3D spatial analyses are applied to assess sun-shadow frequency and visibility constraints relevant to vegetation placement. The paper does not present a full evaluation of regreening outcomes, as several monitoring activities and participatory compo-nents are still in progress. Instead, it introduces a low-cost, multi-layered meth-odological framework that integrates environmental monitoring, behavioural mapping, and spatial analysis as a basis for more targeted and evidence-based ur-ban regreening strategies.

ABSTRACT. Urban planning plays a pivotal role in enabling zero-carbon community development by coordinating spatial layout, land use, building energy performance, transport networks, and renewable energy integration at the neighbourhood scale. However, the policy framework governing such development is highly fragmented: regulations cascade from national carbon-peaking strategies through municipal planning schemes to district-level construction standards, employing heterogeneous terminologies, exhibiting progressive indicator refinement, and embedding implicit cross-document interdependencies—posing significant navigation barriers for planners and practitioners. Conventional keyword retrieval lacks semantic understanding of these hierarchical policy structures, while large language models (LLMs), despite powerful generation capabilities, suffer from hallucination, knowledge obsolescence, and absence of source traceability in policy-sensitive tasks. This paper presents HiRAG, a hierarchy-aware multi-granularity retrieval-augmented generation (RAG) framework integrating LLMs with domain-adapted retrieval mechanisms for intelligent navigation of urban planning and zero-carbon community policies. Taking Shenzhen as a testbed, a knowledge base of 36 policy documents across national, municipal, and district governance tiers is constructed. The framework features hierarchy-aware chunking preserving legislative chapter–section–article–clause structures, a two-stage coarse-to-fine hybrid retrieval pipeline with query-intent-aware filtering, and a query-decomposition-driven extract–synthesize generation mechanism with forced source traceability. Comparative experiments against Direct LLM and Naive RAG baselines, supplemented by ablation studies isolating each component’s contribution, demonstrate that HiRAG achieves 89.27% factual accuracy, 90.17% citation rate, a hallucination rate of only 13.00%, and 98.48% cross-document recall, confirming the superiority of domain-adapted design over generic approaches. This work demonstrates how domain-adapted AI can transform fragmented urban planning governance into an accessible, traceable knowledge system, providing a replicable paradigm for evidence-based zero-carbon community deployment at scale.

ABSTRACT. This study presents a dynamic simulation of a renewable-based hydrogen production facility for vehicle refuelling stations in Southern Italy. The system couples a photovoltaic plant with an anion-exchange membrane electrolyser. Hydrogen is produced either using electricity supplied by the photovoltaic plant, resulting in green hydrogen, or using electricity imported from the national grid, resulting in yellow hydrogen. The produced hydrogen is first stored in a low-pressure tank, then compressed and transferred to high-pressure storage for automotive dispensing. Five electricity-supply configurations are compared: (I) a grid-only reference case, in which all electricity is imported from the national grid; (II) a fixed-tilt photovoltaic plant; (III) a solar-tracking photovoltaic plant; (IV) a fixed-tilt photovoltaic plant combined with battery energy storage; and (V) a solar-tracking photovoltaic plant combined with battery energy storage. The analysis quantifies the renewable and grid contributions to hydrogen production and evaluates annual energy performance, environmental impacts, and economic indicators under local weather conditions, providing a consistent basis for assessing alternative layouts and operational strategies for green hydrogen refuelling applications.

ABSTRACT. This study develops a climate‐responsive operational model for a grid‐connected photovoltaic and hydrogen‐based microgrid at a university campus in Mediterranean Southern France. The microgrid comprises a 660.36 kWp photovoltaic (PV) system, a 120 kW electrolyzer, a 150 kg hydrogen storage tank, and an 80 kW fuel cell, serving a campus with seasonal cooling and heating demands. A multi‐objective formulation minimizes operational cost, grid dependency, and carbon emissions while maximizing renewable self‐consumption. The model integrates dynamic energy balances, hydrogen storage equations (corrected with lower heating value), grid exchange limits, and climate‐dependent control parameters. Simulations using one‐year 5‐minute resolution operational data compare a baseline scenario (no storage) with optimized hydrogen storage operation under a climate‐adaptive rule‐based strategy. Results show that during spring (March–May), the optimized control reduces grid import by 10.4%, lowers natural gas consumption by 8.8% (through waste heat recovery), reduces operational cost by 0.5%, and cuts carbon emissions by 9.5% compared to the baseline. The hydrogen storage system produces 3,056 kg of hydrogen annually, with a maximum state of charge of 71% and fuel cell generation of 56.0 MWh. Seasonal self‐sufficiency reaches 100% in summer due to high PV generation, while winter remains heavily grid‐dependent (26.2% self‐sufficiency). Although the absolute improvements are moderate, the study demonstrates that hydrogen storage can enable seasonal energy shifting and reduce fossil fuel consumption, particularly during the spring surplus period. The proposed climate‐responsive framework is transferable to other Mediterranean regions and provides a practical pathway toward low‐emission campus microgrids.

ABSTRACT. Accurate photovoltaic performance prediction under varying irradiance and temperature conditions is essential for photovoltaic system assessment and long-term energy estimation. This study proposes a modified one-diode model that introduces temperature- and irradiance-dependent formu-lations for the series resistance (Rs) and shunt resistance (Rsh). Indoor ex-periments were conducted on an amorphous silicon photovoltaic module under controlled irradiance and temperature conditions, and the measured I–V characteristics were used for parameter extraction and model valida-tion. The proposed model was compared with the established California Energy Commission (CEC) five-parameter one-diode model using maxi-mum power prediction and statistical indicators, including (R2), RMSE, nRMSE, and prediction error. The results show that the proposed model provides improved prediction accuracy, demonstrating the effectiveness of the modified resistance formulations. This work confirms the feasibility of using simple indoor tests for PV model parameter extraction and provides a basis for future outdoor experiments and multi-climate validation.

ABSTRACT. The article explores the results of the Making PEDs project, which led to the development of a digital platform designed as a tool to support decision-making processes and participatory urban transformation for Positive Energy Districts. Using CityGML 2.0 standards and standardized open-source data for urban modeling, the platform builds scenarios based on four thematic domains: energy consumption, social and energy vulnerability, environmental impact and economic impact. This contribution focuses specifically on the participatory process implemented within the Italian case study of San Liborio, an area of public social housing located in Civitavecchia, a city along the Lazio coastline. The adopted methodology is grounded in the theoretical framework of Urban Living Labs and involved professionals, municipal administrators and citizens. The participatory pathway, articulated through phases of information, dissemination to the population, consultation and feedback, made it possible to highlight potentials, criticalities and needs of the specific context, characterized by the central role of the public institution, the presence of high levels of social vulnerability and the fragmented availability of data. In conclusion, the objective of this work is twofold. First, it demonstrates the potential offered by the Making PEDs platform, a shared environment for the integration, visualization, and interpretation of urban and energy data, useful to support the co-construction of scenarios and the comparison of design alternatives. Then, it questions the criticalities related to the integration of technical and official open data, international standards, and local knowledge for the development of such a platform.

ABSTRACT. Movable insulation systems have attracted growing interest as a strategy to enhance the thermal adaptability of building envelopes and improve building energy performance under variable climatic conditions. These systems in-clude various solutions that modify the thermal configuration of the enve-lope through the displacement or reconfiguration of insulating components. Existing studies have examined such systems across different climates, building types, and design approaches. However, existing literature reviews are often organised according to typological or construction-based classifica-tions, rather than by the underlying heat transfer mechanisms that govern their thermal behaviour. This article presents a review of movable insulation systems with a particular focus on the underlying heat transfer mechanisms through which they affect envelope performance. The review analyses how movable insulation influ-ences conductive, convective, and radiative heat transfer, and how these mechanisms relate to the thermal behaviour of the envelope in different op-erating modes. The review also addresses how performance has been mod-elled and assessed in the literature, identifying this as a comparatively under-explored dimension of movable insulation research. By structuring the literature around fundamental heat transfer processes, the review aims to provide a coherent framework for interpreting existing re-search, identifying knowledge gaps, particularly in modelling and perfor-mance evaluation.