ABSTRACT. Graphene is   important for many energy storage applications due to their tunable solubility, bio-compatibility,  unique optical and electronic properties. For instance, graphene ribbons, sheets and quantum dots  have been studied theoretically  and experimentally  for their size-dependent  light emission and   calculations  using nitrogen doping suggest that nitrogen atoms located at their edge and near the edge  promote the electrocatalytic activity  towards the oxygen reduction reaction, even to replace noble metals like platinum for fuel cell applications.  Similarly applications as electrode materials   supercapacitors and Li-ion batteries have been explored recently  by many groups due to the possibility of developing a smart electrode with intrinsic state-of-health indicator. In this lecture   I will describe the  mechanistic aspects of  the transformation of carbon nanotubes to graphen nano ribbons(GNRs)  and   GQDs  using spectro-electrochemical  data collected by in situ experiments to unravel  some of their unique size dependent features, beneficial for energy storage. Spectroscopic techniques such as X-ray photoelectron spectroscopy(XPS), UV-visible  spectroscopy, and Photoluminescence measurements would be used in conjunction with electrochemical techniques to demonstrate their unique electronic structure for average GQDs  from high resolution transmission electron microscopy and Atomic force microscopy as  3 ± 0.3 nm.  Multifunctional properties such as electrocatalytic properties, Photoluminescence, Electroluminescence and unique single  electron transfer behavior  of these individual graphene quantum dots  and graphene nanoribbons would be discussed with a view to  facilitate their application potential in electrochemical energy storage(1-4).

References:

1. Electrochemical Unzipping of Carbon Nanotubes for  Facile Synthesis   of   High-Quality Graphene Nanoribbons,  Dhanraj B. Shinde, et al,  J. Am. Chem.   Soc.  133(2011)4168
2. Electrochemical Preparation of Luminescent Graphene Quantum Dots from Carbon Nanotubes,  Dhanraj B. Shinde and V. K.  Pillai, Chem. Eur. J. 18(2012) 12522
3. Electrochemical Resolution of Multiple Redox Events for Graphene Quantum Dots, Dhanraj B.Shinde, Vijayamohanan K. Pillai, ,  Angew   Chem. Int. Ed.  47(2012)56
4. Sequential Electrochemical Unzipping of Single-Walled Carbon Nanotubes to Graphene Ribbons Revealed by in situ Raman Spectroscopy and Imaging,  Robin John, et al  ACS Nano (2014)

ABSTRACT. A novel concept of self-repairable glass useful as seals in Solid Oxide Fuel Cells (SOFC) is proposed, developed, and used for making metal-glass-ceramic seals for enhancing reliability and life. In this concept, cracks created during SOFC operation are repaired by the crack healing process driven by the viscous flow of the glass. An approach for studying the kinetics of crack healing in glasses responsible for the self-repair is described and used to study the crack healing behavior. A crack-healing model, based on the relationship among crack length, time, temperature, glass viscosity and its flow behavior is developed in order to describe and predict the time required for self-repair on a glass surface. The predictions from the developed model is then compared with the experimental data and found to be in good agreement. These results also demonstrated the relative importance of the different stages of crack healing on the overall healing or self repair behavior. These along with a review of the current status of sealing technology for SOFC will be discussed.

ABSTRACT. Carbon materials are being used  for  both energy harvesting and for energy storage devices. Many challenges arise when building devices from, particularly in the preparation of these materials as well as in their modification, functionalization, and stabilization. The interesting field for real world application is the fuel cells, batteries  and supercapacitors,  which convert the chemical energy in to  electricity.  Activated carbon  find interest as storage medium for hydrogen in molecular  form due to its high surface area and porosity.  Activated Carbon materials were cost effective and low density as compared to Metal hydrides, Alloys and other materials. Activated carbon with high surface area and microporosity is suitable for storage hydrogen at ambient condition. Fuel cells , which are one of the arms in the energy conversion devices, require catalyst layers for reduction and oxidation reactions at the electrode/electrolyte interface. Pt can be used for these applications, either  as ultrathin films or  as nanoparticles. These catalyst particles can be mono- or bimetallic nanoparticles of Pt and/orRu. The nanoparticles are typically supported on carbon black but alternatively, a carbon nanotube network structure can be used. Similarly Li-ion batteries also  use  carbon based materials for their anode.  At CFCT we are working on developing activated carbons from various precursors obtained from agricultural wastes and are being studied for various energy related applications. These  topics will be discussed. 

ABSTRACT. Carbon, derived from human hair through an economically viable and an environmentally benign approach is found to contain hetero atoms such as  N and S, due to which the sample exhibits multifunctional properties, desirable for its application in energy storage and geneartion related devices. When explored as an anode for LIBs, the  human hair derived carbon (HHC), bestowed with mesoporous nature and an appreciable BET surface area of 1617 m² g^-1 exhibits a steady state reversible capacity of 700 and 610 mAh g^-1 against 50 and 100 mA g^-1 current density. An acceptable capacity of 181 mAh g^-1 has also been exhibited at 10.21 C rate, by withstanding a current density of 3800 mA g^-1. The inter layer distance of  >0.37 nm offers advantages in terms of exploiting the same as an anode for SIBs, wherein an accepatble capacity of  210 mAh g^-1 has been delivered at C/10 rate. Further, with the advantages reaped from the presence of N and S, the defect chemistry triggered electrocatalytic effect has also been found to play a key role in promoting the HHC carbon as a potential and metal-free electrocatalyst for the ORR process involved in fuel cell applications. In addition, HHC acts as a promising additive to prepare a wide variety of M_xO_y/C composites, wherein the electrochemical performance is found to get improved significantly due to the synergistic effect of added HHC. The study demonstrates the exploitation of a universal waste material, viz., human hair, as a potential electrode for the most sought after energy generation and storage applications. Further, the process of filth-to-wealth conversion is bestowed with economic and environmental benefits, thus qualifying itself as an energy efficient process.

ABSTRACT. The most important power-loss-mechanisms in a standard single p-n junction solar-cell are the inability to absorb photons with energy less than the band-gap and thermalization of electron-hole pairs generated by absorption of short-wavelength-photons of energy exceeding the band-gap, through electron/hole relaxation to the conduction/valence band-edge. The ‘Third-Generation- Photovoltaic-Strand’ targets on the more efficient utilization of above and below band-gap photons, simultaneously using abundant, non-toxic materials (e.g., silicon) and processes (e.g., thin-film- technology) those are amenable to large-scale-production. The Si-QDs of dimension ~Bohr-radius produce confined-energy-levels through quantum-confinement in all three dimensions. For closely spaced QDs significant tunneling effect helps to form a true-mini-band and results widening in the effective-band-gap of the tailored quantum-dot-materials, in which Si-QDs are embedded either in dielectric-matrix or superlattice-structure. This in turn can be used to fabricate the tandem-structure cell, wherein individual cells with increasing band-gaps are stacked on top of each other such that each cell absorbs a different part of the solar-spectrum with a narrower range and hence more optimally for each absorbed photon. The sum of the output from these cells can boost the overall efficiency beyond the conventional one. 

ABSTRACT. Highly transparent nano-diamond (NCD) and diamond-like carbon (DLC) films are produced by Micro-Wave PECVD and Radio-Frequency magnetron sputtering, respectively for comparative study on application perspective, as antireflection coating (ARC) for silicon solar cells. Considering application of ARC on the already fabricated top electrode of solar cells, the typical synthesis techniques are selected on the basis of their advantages of being the low temperature processes. Optical band-gap (Eg), transmittance, reflectance, ID/IG ratio in Raman spectra and sp3-fraction of the films have been estimated and the magnitude of refractive index has been optimized between that of air (n=1) and Si (n=3.4), satisfying the basic requirement. Economic development of commercially viable ARC-grade NCD and DLC films are developed for Si solar cells without any external heating of the substrates.

ABSTRACT. The growth mechanism of the active layers of twin donor layer organic solar cell based on zinc and copper phthalocyanine materials at different substrate temperature and its influence on the device performance has been investigated. AFM measurements show the variation of morphology of the thin films with different substrate temperature. Devices with active twin layer deposited in 150 ᵒC are found to have the highest short circuit current 1.26 mAcm-2 and show the highest efficiency 0.2%. The other electrical characteristics of the as fabricated devices were obtained by investigating the current–density (J-V) curve, the fill factor (FF) and external quantum efficiency (EQE) and electrochemical impedance spectroscopy (EIS) analysis.

ABSTRACT. Recently, research on Si-conducting organic polymer heterojunction solar cells has gained prominence owing to their low fabrication cost and relatively good efficiency potential. Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) coated over n type Si forms such heterojunction which has theoretical capabilities comparable to the conventional p-n Si junction. However these devices still need fabrication parameters optimization in order to compete with conventional p-n junction silicon solar cells. Here, we report the response of Ag/PEDOT:PSS/n-Si/Al solar cell at different light intensities and different wavelengths. The device is fabricated by spin coating PEDOT:PSS over textured n-Si. The response of cell with varying intensity can help to optimize the illumination condition for the cell. The wavelength response of the cell can help us better understand the solar cell working and can help in optimizing the fabrication parameters. It is observed that the fill factor deteriorates significantly at higher intensities and the solar cell performance is best at 900 nm wavelength. It is further noted that the short circuit current is significantly lower in I-V response than that derived from quantum efficiency measurements. This is suggestive of some space charge build up at Si-PEDOT:PSS interface at higher intensities because of difference in hole mobility in Si and PEDOT:PSS.

ABSTRACT. Hair is discarded material for our societies and easily found in municipal waste as polluted materials. And large volume is occupied by hair fiber in dumps/waste streams due to slow degradation. So the best way is to develop the approach for utilization the waste material as resources or raw materials. Polymer composites are very common and light weighted material to use everywhere with different reinforced materials. This research work has been investigated the mechanical properties of hair fiber reinforced composites. These reinforced composites are shown the effect of fiber loading and fiber ratios on HDPE polymer reinforced composites in terms of the mechanical behaviour of composites, and also compared the effect of treated and untreated fiber on reinforced polymer composites. Water absorption and FTIR analysis are also done for the study of reinforced polymer composites. These type of fiber reinforced polymer composites are very useful for our society to utilize the waste materials as resources.

ABSTRACT. In the first part of my talk, I will be talking about rationally designed organic molecules that hold promise for the applications in opto-electronic devices like OPVs, OLEDs, etc. We mainly designed the donor-acceptor based molecules by adopting three schemes in which conjugation length, planarity, and strength of the donor and acceptor moieties are varied to tune the electronic and optical gaps. Our results reveal that all these schemes work well and can help in tailoring the electronic and optical gap over a wide range varying from 0.7 to 3.7 eV, that covers a broad range of the light spetrum. These molecules are also found to be air-stable and predicted to exhibit high charge carrier mobility, with the presence of ambipolar characteristics in few of the investigated molecules, which make them suitable candidate for device applications. The other part of my talk will focus on investigation of the yet unknown Li-Sn phases, that are thermodynamically stable at ambient conditions. Interestingly, we discovered the most Li-rich phase, Li5Sn1, that can store ~13% more Li-atoms as compared to the known maximum ithiated phase, Li22Sn5. This study can provide a new dimension in the research of Li-Sn batteries. 

ABSTRACT. In order to meet emission norms, modern day diesel engines rely on methods of in cylinder emission reduction and expensive exhaust after treatment devices. Engine manufacturers across the world are finding it hard to maintain balance between customers demand for better fuel consumption and obeying the stringent legislative emission regulations. Optimum combination of variables such as piston bowl shape, compression ratio, fuel injection and turbo charging systems precisely matched with engine, Exhaust Gas Re-circulation (EGR) rate etc. can result in refined combustion leading to better engine out emissions as well as fuel efficiency. The naturally aspirated single cylinder diesel engine used for this research had its dilute emission passed at the 800 kg inertia class category using continuous EGR. The need for this research arises due to the requirement of passing the above engine with the higher 910 kg inertia class category. Since this up-gradation of inertia class has its effects on the total vehicle emission, the primary task of this research was to investigate the principal pollutant of NOx and its coherence with the corresponding PM levels. Even though the above investigation is concerned with the emission norms, the customer satisfaction of better performance and fuel economy must also be optimized. The overall changes made to achieve the target includes retarded injection timing, use of proportional EGR & exhaust after treatment to achieve emission with minimum 10% margin for all the pollutants from the base emission values.

ABSTRACT. Cyclone separator is a stationary mechanical cleaning device. Objective of the present study involves development of experimental cyclone model for fluidized bed gasifier. An experimental model developed in laboratory and investigation was performed on a laboratory scale model of a gas cyclone separator. The cyclone separator design is stairmand high efficiency cyclone separator and experiment investigations on the flow field characterization and collection efficiency of the Stairmand cyclone separator. The barrel diameter D = 190mm and all other dimension are define from barrel diameter. Approach of CFD modeling in ANSYS Fluent 15.0 has been employed to simulate the three dimensional, unsteady turbulent gas solid flows in a cyclone separator. The effect of the tangential velocity on the performance and flow field pattern has been investigated computational fluid dynamic using the Reynolds stress turbulence model for fluidized bed gasifire. Collection efficiency of cyclone separators has been numerically investigated using the Reynolds stress turbulence model (RSTM).

ABSTRACT. Under certain operating conditions, the rapid expansion of steam through a high-speed nozzle causes condensation. Droplets formed as a result of condensation causes wetness losses which are classified into mechanical and thermodynamic. A significant contributor to the wetness loss is the thermodynamic loss associated with the latent heat released during condensation. The thermodynamic loss is estimated in terms of change in entropy due to condensation. Using this method, a numerical analysis is made to predict the thermodynamic loss coefficient, in the present study. A two-dimensional converging–diverging steam nozzle has been investigated. A density based Eulerian-Eulerian approach is used to model the flow and the phase change mechanism. The aim of this paper is to study the behaviour of the thermodynamic loss.

ABSTRACT. Compact heat exchangers are used in many domestic and industrial systems such as electronic cooling, refrigeration, automobile engine cooling, etc. Even a small increase in the effectiveness of heat exchanger considerably reduces the total energy consumption. In the present study an attempt is made to enhance the heat transfer and overall performance of the heat exchanger by inserting symmetric airfoil pins as secondary fins symmetrically between the tubes. A three dimensional numerical simulations are carried out in the laminar flow regime (in the velocity range 0.5 to 2.5m/s) by using finite volume method based solver ANSYS FLUENT 15.0. The effect of mounting location and orientation of the airfoil pin fin on flow and heat transfer characteristics and overall performance of the heat exchanger are investigated.The percentage rises in pressure drop due to airfoil pin-fin insert are 29.01 and, 41.14, respectively for 0.5and 2.5m/s of flow velocities. Similarly,the percentage rises in heat transfer coefficientare2.54 and13.31.Optimum location and orientation of the pin-fin inserts with better overall performance are identified.

ABSTRACT. Ambient temperature sodium-ion batteries (NIBs) are expected to play a key role in the future as an alternate battery technology to lithium-ion batteries, especially for stationary storage applications where the weight and size of a battery are not crucial. In this context, implementation of NIB systems for handling the intermittency of renewable sources such as solar and wind will be especially attractive. Factors such as globally abundant sodium reserves and the identification of some newly discovered high energy density NIB cathodes^[1] could make NIBs feasible for future electrical energy storage systems. However, such high performance NIB cathodes would need an equally capable anode. In this talk, we will present our results on the sodium storage characteristics and performance of some phases within the sodium titanate family operating as low voltage NIB anodes. In particular, we will discuss three separate NIB anodes^[2-4] from this family which have individually attractive features for different stationary storage applications. Furthermore, we will discuss our analyses on the unreliability of sodium metal acting as a counter electrode with special considerations to the possibility of erroneous data interpretations in sodium half cells^[5] with some specific examples.

References

[1] D. Kundu, E. Talaie, V. Duffort, L.F. Nazar, Angew. Chem. 54 (2015) 3431-3448.

[2] A. Rudola, K. Saravanan, S. Devaraj, H. Gong, P. Balaya, Chem. Commun. 49 (2013)  7451-7453.

[3] A. Rudola, K. Saravanan, C.W. Mason, P. Balaya, J. Mater. Chem. A 1 (2013)  2653-2662.

[4] A. Rudola, N. Sharma, P. Balaya, Electrochem. Commun. 61 (2015)  10-13.

[5] A. Rudola, D. Aurbach, P. Balaya, Electrochem. Commun. 46 (2014)  56-59.

ABSTRACT. Prabaharan et al first reported on the possibility of using a rocksalt type Li2NiTiO4 as a positive electrode for Li-Ion batteries and proven that the redox energy for the reaction Ni2+/4+ and Ti4+/3+ would favor facile redox reactions. We present here our first report on the possibility of using Li2NiTiO4 as pseudocapacitive electrode and demonstrate the Li-Ion hybrid capacitor. It is deduced that the specific capacitance (~100 mAhg-1) by converting its specific capacity into capacitance and used the same against a pure porous carbon electrode (AC) as Li-Ion capacitor couple, Li2NiTiO4//AC yield ~1.8 V in aqueous electrolytes. The important result is that both Ti and Ni activities were used for both low voltage aqueous cell respectively as the former exhibits redox activity close ~1.5V vs. SCE whereas Ni2+/4+ activity has been found to yield two electron transfer corresponding to oxidation/reduction. Specific capacitance of Li2NiTiO4 was measured using three electrode cell in Li+ alkaline electrolytes against Ag reference electrode charge/discharge and impedance profile were compared. A hybrid Li-Ion capacitor Li2NiTiO4//AC was fabricated and studied for its capacitive performance.

ABSTRACT. We synthesized LiFePO4 and Li3V2(PO4)3 cathode materials using sol-sel route in nanostructure geometries and microstructural properties are investigated. X-ray diffraction measurements confirmed that LiFePO4 and Li3V2(PO4)3 crystallized into orthorhombic and monoclinic structures. The particle size was found ~ 18nm and 24nm for LiFePO4 and Li3V2(PO4)3 respectively. Scanning Electron Microscope (SEM) and Energy Dispersive X-ray (EDX) measurements confirm granular microstructure and right stoichiometry of synthesized materials. We will discuss the electrochemical performance, such as cyclic voltammetry and charge-discharge characteristics for these synthesized materials in half cell configurations.

ABSTRACT. Amongst energy storage devices, Lithium Sulfur (Li-S) batteries are gathering immense interest because of inherent higher theoretical energy density (2600 Whkg-1) and capacity (1672 mAhg-1) of elemental sulfur. However simultaneous dissolution of sulfur in the electrolyte affect both cyclability and performance of these energy devices. Recently to address this issue, inverse-vulcanization based polymer composites have received attention as promising cathodic materials for Li-S batteries. However, the exploitation of sustainable materials especially in the urge of utilization of renewable energy sources necessitated the development of materials which are naturally abundant and have minimal toxicity issues. In present work we unfold new class of alternative materials prepared via-sustainable route to counter the problems associated with current Li-S batteries.

ABSTRACT. Abstract: In a solar photo voltaic system battery has to operate under varying environmental and loading conditions. The health and performance of a solar battery is affected not only by the depth of discharge but also by the operating temperature of the battery. Further, a battery is not only affected by the ambient temperature but also by its internal temperature. Where the ambient is usually a natural phenomenon, the internal temperature is a result of extreme loading conditions or improper charging profile. Though the ambient is not in our hands but the internal temperature should be controlled as the co-existence of both these factors can result in early ageing of the battery. In a country like India, where the ambient temperature has wide differences, it becomes essential to consider the effect of temperature on battery, while designing a solar photo voltaic system. This paper presents the study of effect of both internal and external temperature on capacity of flooded lead acid battery samples with respect to charging voltage. A charging profile for usual operating temperature conditions is also suggested.

ABSTRACT. The commercial and residential buildings consume about 33% of energy for cooling and day lighting in India. This paper presents the thermal performance of buildings constructed with various building and window glass materials in five different climatic zones of India, such as composite (Delhi), hot and dry (Ahmedabad), warm and humid (Madras), moderate (Bangalore) and cold (Guwahati) climatic zones. In this study, four building materials such as, laterite stone, dense concrete, burnt brick and mud brick were selected and four window glass materials such as, clear, bronze, green and reflective glasses were selected. This paper also presents the experimentally measured solar thermal properties of four glass materials studied. The building models with the measured thermal properties were designed in Design builder software and thermal analysis was carried out in Energy plus. From the results, it is observed that mud brick with reflective glass window buildings were found to be energy efficient due to the less heat gain into the buildings among twenty studied building models in five different climatic zones of India. This study helps in selecting the best combination of building and window glass materials from a low heat gain perspective in different climatic zones.

ABSTRACT. Grid connected or grid tied inverters connecting photovoltaic (PV) modules to the power grid is now considered a significant grid power supplement. There is a high penetration of these PV systems into the power grid. These systems need to adhere to power quality and safety requirements that are imposed by electric supply companies in order to maintain a stable and quality grid. For this to happen, the output waveform of the inverter need to have low total harmonic distortion (THD), zero DC injection and ac power decoupling. There are many PV based grid tied inverters that use two-level inverters. These are operated at higher frequencies to achieve required performance. Operating power devices at higher frequencies leads to higher power losses. Since last decade, multilevel inverters have become more attractive for researchers and manufacturers due to their advantages over conventional two-level inverters. They offer improved output waveforms, smaller filter size, lower EMI and lower total harmonic distortion (THD).

The conventional topologies for multilevel inverters are, i) diode clamped (also called neutral point clamped); ii) capacitor clamped (flying capacitors); and iii) cascaded H-bridge configuration. In addition, several modulation and control strategies have been developed or adopted for multilevel inverters, including the following: multilevel sinusoidal (PWM), multilevel selective harmonic elimination, and space vector modulation. These inverters require large number of switches, diodes, balancing capacitor and DC sources.

This paper proposes a novel topology that is specific to PV based grid tied inverters. Here an attempt is made to reduce the number of power switches for a given number of inverter levels and also to address all the drawbacks mentioned above. Further the proposed topology does not require a very large DC link capacitor that is normally used in conventional grid tied topologies.

ABSTRACT. The Thermoelectric Power Generators (TEG) are solid state devices which utilize temperature gradients to produce electrical energy. In domestic wood-stoves, these devices have carved out a niche for themselves and can be used for generation of electricity in rural areas. This paper presents the design of a shield based thermoelectric power generation system consisting of a thermosyphonic heat sink, for utilization in wood stoves. The average current density of the TEG module improved by 28.3% and 22.3% when compared to the conventional plate fin heat sink based converter system and a simple single loop thermosyphonic heat sink based converter system respectively. The converter system achieved a maximum power output of 3.2 Watts along with a maximum conversion efficiency of 5.05 % which was higher than the conventional heat sink based module systems in wood burning stoves. An optimal shield thickness of 6 cm reduced the steady state hot side temperature below the permissible limit and an optimal coolant velocity of 8 m/sec ensured efficient removal of heat from the cold side of the generator

ABSTRACT. We present that CO2 can also be used as best working fluid in subsurface to harness large amount of energy because of its excellent thermodynamic and fluid mechanical properties like thermosyphon effect which can transfer heat more efficiently than water/brine systems. Production of electric energy along with its supply in conjunction with CCUS can improve economic viability of CO2 sequestration which is the major challenge for its large scale implementation in India. In this work we present results of calculations demonstrating the potential of geothermal energy capture in CO2 based geothermal system and its implications on geologic CO2 sequestration in terms of economic viability for India geothermal provinces.

ABSTRACT. This paper deals about the reduction of power drawn from the supply system during generation uncertainties in D.C Micro grids using D.C Electric springs. In this work supply system is modelled using a fluctuating power source and a battery i.e. during generation uncertainties the system runs on battery support. In this work power conservation is achieved by making the non-critical loads draw less power during generation uncertainties which in turn relives the battery and renewable generator to the possible extent. A small micro grid system which has a critical load and non-critical load has been taken for the study and the simulations are done in MATLAB. D.C Electric springs are extension to A.C Electric springs used in A.C systems which make the non-critical loads draw less power by adjusting the voltage applied to them.

ABSTRACT. This paper discusses the energy savings in radial distribution systems with wind turbine integration with probabilistic load power demands. The energy savings are determined by calculating the difference cost of energy losses of the distribution system without and with the wind power source. Deterministic load flow (DLF) studies do not incorporate the randomness of the load power demands. The probabilistic load flow (PLF) method incorporates this randomness to provide more realistic and accurate results regarding the performance of the system. In this paper, the load and the substation voltages of the distribution system are considered as random variables for the calculation of energy savings. The main contributions of this paper are: i) Comparison of annual energy savings and cost of energy losses obtained using DLF and PLF calculations ii) Analysis of 24 hour energy savings of radial distribution systems with the integration of wind turbines using practical 24 hour wind data iii) Comparison of energy savings of radial distribution systems for winter and summer seasons. This study can help extensively in the realistic analysis of radial distribution systems with renewable integration. The results are obtained for a standard IEEE 33 bus radial distribution system.

ABSTRACT. Silicon nanowires (SiNWs) are promising building blocks in various research areas of modern nanoscience and nanotechnology. Vertical SiNWs arrays exhibit low reflection, strong broadband absorption and may be used as efficient light absorber in solar cells. In addition, SiNW arrays also have the potential for efficient charge carrier collection across the nanowire diameter for radial junction (homo/hetro p-n junctions) solar cells and therefore may relax high quality material requirement, enabling lower-cost photovoltaic (PV) cells. Here, recent R&D efforts to realize such PV devices with an emphasis on minimization of reflection losses through TWO nano-structuring schemes and their application in silicon solar cells would be briefly discussed.

ABSTRACT. Current efforts have been given to develop new photovoltaic materials to improve the efficiency with reducing cost. The factors that have been taken into account in developing new photovoltaic materials include: a suitable energy band gap, the possibility of depositing the material using low cost deposition methods, abundance of the elements and low environmental costs with respect to the synthesis of the elements, production, operation and disposal of modules. It’s been a long time that continuous efforts has been given to find out the most appropriate material to be employed as absorber material for solar cell and some advanced material has been proposed too as potential solar cell material. Here in our present study we have taken Cu2-xS as a suitable p-type absorber layer material but the formation of stable Cu2-xS film was being difficult task. Different researchers proposed different methods among them we have found the elemental stacked layer deposition method is one of the promising technique. But this technique requires further optimization on thickness and layer no’s to get the best result with required stoichiometry. With this context we have tried to optimize the thickness and layer no’s for developing multilayer Cu2-xS thin film on the glass substrate by physical vapour deposition technique. The results obtained in this method shows that the optimum numbers of layer is 10 ensures formation of crystalline Cu2S structure with optical band gap is around 1.65 ev to 1.85 ev by different characterization technique like XRD, EDX, SEM, Spectrophotometry and PL. The I-V characteristic of Schottky junction using silver with the sample shows semiconductor behavior of the same. To the best of our knowledge this is the first time such type of nano-structured Cu2S film fabrication is reported.

ABSTRACT. Cu2ZnSnS4 (CZTS) is a promising candidate as an absorber material for thin film solar cells. In view of large fluctuation in Indium pricing and relative environmental impact of processing Gallium, CZTS presents itself as a viable alternative to CuInGaS2 (CIGS) based technologies. The primary methods used for fabricating CZTS thin films include sputtering, co-evaporation, electrochemical synthesis and wet chemical routes. Whereas sputtering and co-evaporation suffer from issues like high energy input, non-scalability and intensive infrastructural costs, phase formation is a critical issue with electrochemical synthesis and co-evaporation. The wet chemical approaches for making CZTS thin films suitable for solar cell applications include solvothermal routes, nano-ink based techniques and direct liquid coating technique. The reported wet chemical synthesis approaches often have a high environmental impact due to the usage of abrasive solvents such as hydrazines, hydroxylamines, etc. We report an eco-friendly solvent based approach for making CZTS thin films with desirable absorption characteristics for solar cell applications. By changing the relative ratios of precursors, we are able to make Zn rich and Zn poor counterparts with associated band gap tunability.

ABSTRACT. A low cost non-vacuum solution process has been developed for Cu2ZnSnS4 (CZTS) thin film synthesis without any external sulfurization. The metal chloride salts are used to prepare CZTS sol and its viscosity has been tailored for homogeneous thin films using spin coating. The spin coated thin films are treated under optimized thermal conditions to achieve the right stoichiometry and kesterite CZTS phase. The structure, and stoichiometry of CZTS thin films are confirmed using X-ray diffraction and energy dispersive X-ray (EDX) measurements. The films are tin (Sn) rich and copper (Cu) deficient, causing the p-type carries in synthesized thin films. The optical bandgap of these thin films is ~ 1.52 eV with hole concentration ~ 2.98 x1016 cm-3.

ABSTRACT. Copper Zinc Tin sulfide (CZTS) has shown promising performance as an absorber semiconductor for solar cell devices. Due to multicomponent system, low cost synthesis method results in presence of secondary phases, which is nagging issue it effects optoelectronic properties. In this study, we have achieved the growth of phase pure CZTS nanorods by using appropriate amount of salt concentration in stating solution and optimized temperature CZTS nanorods have been grown by hydrothermal process with Ethylenediamine (EDA) as solvent using optimum constituent salt concentration amount at temperature 200 °C upto 72 hrs. XRD and Raman analysis confirm that grown samples having keseterite phase without any extra impurities. HRTEM images of CZTS nanorod show interplanar spacing of around 0.332 nm having good agreement with XRD results. KPFM method provides information about topography and local work function at nanometric scale. It has been observed that surface potential of CZTS nanorods varies as function of nanorod diameter. Presence of grain boundaries, change in the carrier concentration at the surface, surface defects and variation of chemical composition at surface together results change in surface potential values along. These results are important in terms of the application of CZTS nanorods in solar cell applications.

ABSTRACT. Motivation of the current studies comes from the fact that despite the myriad studies on polybenzimidazole (PBI) based proton exchange membranes (PEM) for fuel cell operating above 100^°C, the development of membranes with higher proton conductivity with workable mechanical strength and low acid leaching are the prime challenges. Our group has developed and been working on several strategies to address these key challenges. Briefly our approaches are: (1) synthesis of tailor made PBI structures, (2) development of a novel fabrication process called 'Gel Process', (3) blending of PBI with suitable polymers, and (4) formation of PBI hybrid nanostructures/nanocomposites with inorganic fillers [1-5].

In this presentation, I wish to share our recent contributions towards the development of PEM membranes designed from tailor made organic/inorganic hybrid PBI nanocomposites and PBI diblock copolymer consisting of nanophase domain. A judicious choice of polymer structure and functionality along with inorganics structures are the key factors to have favourable interactions which yield to nanocomposites. In this presentation, I wish to highlight the preparations, structures and properties of oxy-polybenzimidazole (OPBI), a heterocyclic polymer with ether linkage in the backbone, nanocomposites with varieties of clays and silica particles. Structurally different clays and nano sized silica particles have been used after appropriate organic modifications which induce the compatibility of these inorganic fillers with the PBI/OPBI. We observed that the structure of the inorganics dictates the nanocomposites structures and hence the properties. Newly developed organic/inorganic hybrid nanostructure membranes displayed very high proton conducting behaviour at 160°C and remarkably high thermal, mechanical, and oxidative stabilities. Most importantly, we are able to reduce the acid leaching from the PEM. The lecture will also highlight, the development of PBI diblock copolymer in which the nanophase separation of blocks facilitate the faster proton conduction at higher temperature.  

References

1. Ghosh, S.; Maity, S.; Jana, T. J. Mater. Chem., 21 (2011) 14897.
2. Ghosh, S.; Sannigrahi, A.; Maity, S.; Jana, T. J. Phys. Chem. C, 115 (2011) 11474.
3. Maity, S; Jana, T. ACS Appl. Mater. Interfaces, 6 (2014) 6851.
4. Singha, S.; Jana, T. ACS Appl. Mater. Interfaces, 6 (2014) 21286.
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ABSTRACT. This paper reports the use of artificial neural network (ANN) integrated with genetic algorithm (GA) to predict the performance of direct expansion solar assisted heat pump (DX-SAHP), in Calicut (Latitude of 11.15 0N, longitude of 75.49 0E), India. The performance parameters such as power consumption, heating capacity, energy performance ratio and compressor discharge temperature of DX-SAHP obtained from the experimentation at different solar intensities and ambient temperatures are used as training data for the network. The back propagation learning algorithm with variants Lavenberg–Marguardt (LM) with 10 neurons in the hidden layer and logistic sigmoid transfer function were used in the network to predict the performance of DX-SAHP. Then those values obtained from the analysis using ANN are optimized further by integrating the ANN procedure with GA. The resulting computations confirmed that the use of ANN integrated with GA gives better optimized values compared to the value obtained from ANN for the performance prediction of DX-SAHP.

ABSTRACT. Solar parabolic collectors exploit solar energy for both thermal and power generation applications. But, they demand long arrays of reflective concentrating surfaces with receiver tube throughout the length of axis of the concentrators. For one and half meter long parabolic trough with aluminium sheet as reflective surface, experimental analysis was done attempting to increase the energy transfer rate and reduce the length of arrays. Two absorber tubes were fabricated and distilled water was used as the working fluid in the tubes. The modified absorber tube with hinged blades delivered an average efficiency of 69.33% compared to 60.82% obtained for simple conventional absorber tube. Plots for performance results of the tubes with varying direct normal irradiance and mass flow rates were obtained. Slope and intercept values of 70.887 and -0.419 respectively were obtained for the collector equation of absorber tubes hinged blades compared to slope and intercept values of 61.571 and -0.401 respectively. The present work delivers better performance compared to earlier works Thus, the proposal present its scope for both domestic and industrial applications.

ABSTRACT. This paper presents the design, development and performance evaluation of a compound parabolic concentrator for medium temperature application. In the present study Compound Parabolic Concentrator(CPC) has been used as a non imaging solar concentrator. A single piece of evacuated tube heat pipe solar collector has been used to collect the solar radiation which is concentrated by the CPC. The condenser of the heat pipe has been directly inserted into the storage tank. The performance of the system has been evaluated for different tilt angles. Different performance parameters such as system thermal efficiency and standard power have also been evaluated in this paper.

ABSTRACT. In this paper, effect of wind generation integration has been obtained considering the 24 hour wind speed variation on its output. Mixed integer nonlinear programming (MINLP) approach has been proposed with wind generation integration for determining optimal location and fuel cost savings of conventional generators. The results have been obtained for the fuel cost, total real and reactive power loss, optimal conventional generation schedule and optimal DG sizes and location. The results have been obtained for IEEE 24 bus reliability test system.

ABSTRACT. The introduction of solar energy into Australia has been interesting with solar PV being primarily residential roof-top. We are now seeing large-scale solar farms being proposed, with the first two sites totalling 159 MW in Broken Hill and Nyngan now being commissioned. The University of Queensland has also recently commissioned a 3.275MW Solar PV Research Facility at the Gatton Campus that includes fixed, single and dual-axis tracking arrays. In addition a 760kWh lithium-ion battery system will be installed during the final quarter of 2015. This system will provide valuable learnings in relation to how different PV systems operate, however initially the primary focus is going to be on how the system integrates with the local distribution network and what role the battery storage system will play. The Research Facility has been designed around a number of specific research programs, but with the flexibility to allow for ongoing research and development with the view to look at how best renewable energy technologies can be integrated into distribution networks and the role that control systems and storage will play as the role of distributed energy increases.

ABSTRACT. Integrating absorption chillers with diesel engine generators makes possible the use of its rejected energy for meeting cooling energy demand. The performance of such an absorption chiller is sensitive to the temperature at its desorber section. In hot water driven double effect absorption system, the temperature of hot water is to be maintained between 170 0C and 165 0C. A hot water tank is therefore proposed to be integrated so as to maintain the water temperature within allowable limits. Sizing of such a hot water storage referred to as a thermal stabilizer is therefore an important objective. One such technique proposed is a sizing curve method based on thermal stability time. A generalized methodology for generating a sizing curve for a cooling load is presented in this paper. The method offers a simplified approach for sizing of thermal stabilizer for a given diesel generator catering to combined power and thermal demands. This sizing methodology is illustrated for a 180 kW diesel engine based trigeneration system catering to fluctuating cooling loads.

ABSTRACT. Biodiesel is renewable energy resources that can be derive from numerous sources. In the current study, energy and exergy analysis of variable compression ratio (VCR) diesel engine for Biodiesel has been performed. The Biodiesel is prepared from karanja (Pongamia Pinnata) vegetable oil by two-step transesterification process. A comparative energy and exergy analysis of different blends (petroleum diesel with 0% karanja biodiesel (KB0), petroleum diesel with 10% karanja biodiesel (KB10), petroleum diesel with 20% karanja biodiesel (KB20), and petroleum diesel with 30% karanja biodiesel (KB30),) of biodiesel with petroleum diesel are also been studied on four stroke constant rpm CI diesel engine. Energy and exergy analysis include various calculation of net heat release rate, cumulative heat release rate, net energy destruction rate, first law efficiency, shaft input, available input, second law efficiency, cooling water and exhaust availability respectively. The energy and exergy balance sheet analysis has proof that KB30 blend of karanja biodiesel is most suitable than other karanja biodiesels for CI diesel engine. Due to greater, first law efficiency and second law efficiency KB30 was found to be the most suitable blend for utilization in CI engines.

ABSTRACT. Black liquor is a high energy content by-product of paper mill industries which can be processed to generate energy and help in energy sustainability. In this study, experimental analysis were done to find the various properties of black liquor and characterization of its bio-oil and bio-char obtained through pyrolysis of dried black liquor solids. In the present study, it was observed that temperature has a significant effect on the distribution of products yields. The bio-oil yield was maximum at 500°C temperature with the heating rate of 40°C/min. The bio-oil obtained from Dry black liquor solids (DBLS) has a calorific value of the DBLS bio-oil is 29.86MJ/kg. Chemical composition of the biooils was investigated by using FTIR and 1H NMR analysis. Biochars obtained as by-product were also analysed by using SEM-EDX, FTIR and XRD. It was found that the biochar obtained were basic in nature. Hence, it may be used as a potential liming agent for reclamation of acidic soil.

ABSTRACT. In the present work a venturi type biogas mixer has been designed for converting the commercially available small capacity Spark Ignition (SI) engines to independently operate with biogas. A GK-100 Honda engine was chosen for the study because of its wide use in agricultural, commercial and household appliances as a driver to water pump or as a gen-set. The preliminary design of the biogas mixer was based on fundamental correlation of fluid mechanics and reported methods in the literature. The final dimensions are obtained through exhaustive computational analysis using ANSYS Workbench 14.5. With these proposed dimensions, exhaustive analysis is performed for the variable flow mixer to check the extent of homogeneous air-fuel mixing. The optimum dimensions of biogas mixer have been identified which is supposed to be attached to the engine intake system along with the existing carburetor so as to enable the engine to run with biogas and gasoline independently.

ABSTRACT. Biomass gasification based combined heat and power plants are becoming promising option for site dependent, efficient and environment friendly mode of power generation technique in now a days. However, detailed thermodynamic and economic performance analyses of such biomass based power generation systems are very essential to improve the system performance and to check the economic viability. Again, the implementation of externally firing technique in a conventional biomass integrated combined heat and power plant eliminates the necessity of complex gas cleaning trains and design modification of a conventional combustor. Energetic and techno-economic performance analyses of a externally fired biomass gasification based combined cogeneration plant (EF-BGCCP) is reported in the present paper. The plant is capable of producing 700-800 kW electrical power along with utility heat. Gas turbine (GT) provides fixed 500 kWe power output along with bottoming steam turbine (ST) output. Utility heat of 100 kW or more is also available form the plant. Saw dust is considered as fuel feed to the plant which undergoes gasification in a downdraft gasifier. A combustor-heat exchanger (CHX) duplex unit is used in the topping GT cycle to heat up the working fluid. Schematic diagram of the proposed plant is shown in Fig. 1. Effect of plant design parameters in terms of topping cycle pressure ratio (rp=4-12), gas turbine inlet temperature (TIT=900-1100 deg C), cold end temperature difference (CETD=230-280 deg C) of the heat exchanger of CHX unit and outlet temperature of the economizer (TEOUT=130-180 deg C) on the energetic and techno-economic performance is reported in the study. Energetic performance of the plant is evaluated via energy efficiency, required biomass consumption and fuel energy savings ratio (FESR) of the plant whereas, techno-economic performance is evaluated via levelized unit cost of electricity (LUCE) delivered to the consumers. The FESR calculation method is significant for indicating the savings in fuel of a combined power and heating plant instead of separate plants for power and process heat. Energetic performance of the EF-BGCCP reveals that, plant efficiency along with FESR is maximized at a particular value of rp, for a given GT TIT. Higher TIT results in higher efficiency and FESR value. Again, increase in CETD of the heat exchanger results in decreased efficiency value and FESR value for a fixed TIT and rp value. However increased CETD value results in decreased overall area (UAHX) of the exchanger. Also, increased value of TEOUT results in decrease in plant efficiency and increase in FESR of the plant. Techno-economic analysis of the plant suggest that LUCE value changes with change in operating conditions of the plant. LUCE value is minimized at a particular value of, for a fixed GT TIT. Also, higher TIT results in lower LUCE delivered to the consumers. Again, higher CETD value of the heat exchanger results in decreased LUCE value as the size of the heat exchanger decreases with increase in CETD. The study also reveals that, for a fixed rp , TIT and CETD value lower TEOUT results in higher LUCE value due to increased cost of the steam turbine. The study also discusses on the effect of load factor and subsidies on plant economics. LUCE value decreases with increase in load factor and increase in subsidy on the capital cost of the plant components.

ABSTRACT. The thermochemical fuel characteristics and thermokinetic decomposition of melon seed husks (MSH) was examined under pyrolysis conditions. The activation energy E and frequency factor A for MSH decomposition under pyrolysis conditions were determined using the Kissinger and isoconversional Flynn-Wall-Ozawa (FWO) methods. The kinetic values of MSH using the Kissinger method are E = 161.26 kJ/mol and frequency factor, A = 2.08 x 1010 min-1 with the correlation value, R2 = 0.9958. For FWO the values of E for MSH ranged from 146.81 to 296 kJ/mol for conversion α = 0.15 to 0.60. The decomposition of MSH process was fastest at α = 0.15 and slowest at α = 0.60 with average E and A values of 192.96 kJ/mol and 2.86 x 1026 min-1, respectively at correlation values of 0.9847. The results indicate that MSH possesses important characteristics of a potential solid biofuel (SBF) for future thermochemical applications in clean energy and power generation.

Keywords: Kinetic, Melon, Seed Husk, Thermogravimetry, Nigeria

ABSTRACT. With the ongoing investments in smarter electric grid, several new algorithms and devices have been developed. Synchrophasor applications in transmission systems, distribution automation and adoption of microgrid are some of the most critical smart grid technologies. Synchrophasors devices provide synchronized measurements at faster rates for enhanced wide area situational awareness enabling number of new applications. Distribution automation helps in optimized integrated volt/ var control as well as conservation voltage reduction (CVR). Smart meter data also helps in load modeling and CVR. Microgrid helps in increased penetration of renewable distributed energy sources and high reliability. This talk will discuss about several smart grid technologies and couple of smart grid research, demonstration and implementation projects related to these critical smart grid technologies. This talk will also discuss, what lies ahead in smart grid including emerging smart grid technologies and concept of smart cities.

ABSTRACT. Advances in microgrid enabling technologies and utilization of Renewable Energy Sources are prompting more and more number of smaller investors to invest in Renewable energy generation and distribution at microgrid level. The increased competition requires the energy producers to offer energy at minimum possible cost to gain the confidence of consumers, which needs efficient methods to schedule the energy generation among the available Renewable Energy Sources. Optimal scheduling of generation is one of the methods used to reduce the cost of generation. Out of many types of algorithms used effectively to solve the problem, evolutionary program techniques are proven and time tested to be one of the best solutions. A stochastic based search algorithm, called Artificial Fish Swarm Algorithm is used in this article to solve the problem of optimal scheduling of energy generation among the available Renewable Energy Sources. The effectiveness of the algorithm is validated by implementing to schedule generation in a microgrid scenario. The results are validated by comparing to an already tested Additive Increase Multiplicative Decrease algorithm.

ABSTRACT. Compression Ignition Engines are a significant source of power, both for stationary and mobile applications. The diesel engine presents itself as an attractive source of energy due to their relatively smaller size and lighter weight compared to the magnitude of power it produces. The major concern in harvesting energy from such engines is the nature and amount of toxic pollutants that get released during their operation. Ever since the advent of Clean Air Act in 1970, stringent measures have been in practice to exercise control over the pollution of our planet. Thus the ethics towards preserving the nature has posed the greatest of challenges for engine designers by putting a limit on the extraction of energy from the fossil fuels. Nanotechnology has provided the researchers around the world with an opportunity of overcoming this limitation. Many efforts have been put forward in studying the physical,chemical and thermal properties of a number of species of nano particles and their effect when employed as an additive to diesel fuel or its derivatives. However, no valid works have been effected in blending multiple nano particles in the fuel, integrating the positive effects of both the species at one go. In this work, we present the combined effect of Alumina and Cobalt oxide nano particles,blended in different dosages with neat diesel, on the combustion,performance and emission characteristics of a four stroke, single cylinder diesel engine. The analysis of experimental results revealed a substantial enhancement in brake thermal efficiency of the engine and a marginal reduction in the emission of toxic pollutants.