Advances in Energy Research, Vol. 1

The present work reports on the initial results of experiments conducted aiming to investigate the effects of soiling losses on tilted PV surfaces. Identical glass coupons have been exposed outdoors for eight weeks at different inclinations (0°–36°), and weekly hemispherical transmittance measurements and drop in short-circuit current of solar cell placed under the glass are compared. The results show that the blue end of the spectrum is more affected by dust accumulation. Maximum losses as high as 6.86% and 7.66% in hemispherical transmittance and short-circuit current, respectively, have been recorded during the 8-week outdoor exposure for coupon with 0° tilt angle. Minimum loss occurred for the coupon kept at 36° tilt angle and was found to be 4.86% and 5.02% for hemispherical transmittance and short-circuit current, respectively. It is observed that transmittance drop is linearly correlated with that of tilt angle of a surface. As expected, more the tilt angle of a surface, less is the transmittance drop.

In this study, we investigate the use of silver (Ag) nanoparticles (NPs) to enhance the efficiency of betanin dye-sensitized solar cells (DSSCs) by plasmonic effect. Betanin is a natural pigment with an absorption band in the green region (from 450 to 600 nm peaking at 535 nm). If there is good energy match between the extinction bands of the metallic NPs and absorption bands of the dye, an enhancement in solar cell efficiency can be achieved by incorporating them with betanin in the solar cell. The extinction band of the metallic NPs depends upon its size, morphology and dielectric medium. In order to optimize the nanoparticle dimensions according to the absorption band of betanin, finite-difference time-domain (FDTD) simulations have been performed. The electric field profiles of the AgNPs were studied at ON and OFF resonant wavelengths. It was determined that the performance of DSSCs could be potentially enhanced by incorporating AgNPs of sizes ranging from 50 to 80 nm. An average efficiency of 0.581% is achieved for a betanin DSSC, while an increased efficiency of 0.683% is achieved for AgNP-incorporated betanin DSSCs. The 17.55% increase in efficiency is due to enhanced light harvesting by the AgNPs due to surface plasmon resonance (SPR) which resulted in an increased photocurrent density.

The present chapter focuses on the downshifting properties of ZnS phosphor nanoparticles (NPs). ZnS phosphor NP is successfully synthesized by chemical co-precipitation method. The downshifting technique for solar cell was designed to overcome the energy losses due to the spectral mismatch between the incident solar spectrum and the solar cell. Downshifting layer is placed above the top surface of solar cell. Phase identification and surface morphology were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques, respectively. The photoluminescence (PL) spectrum was studied at a wavelength of 300 nm excitation. The emission peak of nanoparticles was found at 500 nm near the visible region. The transmittance spectrum showed some absorption dips at UV and near the visible area. Moreover, it was used to determine the band gap of the ZnS NP. The prepared ZnS NP/PMMA was applied over the multi-crystalline (mc) silicon solar cell, and the quantum efficiency was measured and compared with the bare solar cell.

The power conversion efficiency of single-junction photovoltaic cell is fundamentally restricted by Shockley–Queisser limit due to broadband distribution of solar spectrum. The intrinsic limit can be exceeded by utilizing high-/low-energy photons above/below the bandgap energy using down/up converters. But these approaches have resulted in meager efficiency improvements so far. Recently, new approaches have been explored to tune the broadband solar spectrum into narrowband spectrum, ideally matched to near-bandgap energy of solar cell, using sub-wavelength photonic structures. In this work, the use of spectrally narrow emitters, optimally matched with the bandgap energy of the photovoltaic cells, is investigated. Here, we propose a grating-based nanophotonic emitter with copper as a substrate and SiO2 as the grating material. Simulations were performed by using rigorous coupled-wave analysis (RCWA) and finite-difference time-domain (FDTD) methods to design narrowband emitters. The optimized grating parameters of period 1.0 µm, duty cycle 0.5, and thickness 0.57 µm resulted in a narrowband emission (peak emission at 1.03 µm with a bandwidth of 20 nm) suitable for integration with silicon photovoltaic cells. The dependency of emittance on directional selectivity is also investigated. The grating-based structures were also optimized for other solar cells.

Luminescent solar concentrators (LSCs) are explored as a cost-effective alternative to traditional solar PV technologies. LSCs based on quantum dots with large Stokes shifts are used to reduce the photon reabsorption losses. However, LSC design still suffers from escape cone losses resulting in inefficient guiding of light to the edges. Here, we propose the integration of high index contrast gratings on the backside of the LSC substrate to reduce these losses. Grating parameters (period, duty cycle, and thickness) are optimized for increasing light guiding efficiency to the edge of the LSC. Simulation results show that an improvement of 14% in the guiding efficiency is achieved compared to the conventional LSCs.

Renewable energy generation has gained much more importance in India than ever before. Photovoltaic (PV)-based electricity generation shares a major portion of renewable energy generation in India. PV-based electricity generation requires land of about 2 ha per MW of installation. Since both food and energy are required for human civilization to progress, here a concept of integrating PV-based electricity generation and crop production from a single land unit is designed and developed, which is known as agri-voltaic system. Such systems of 105 and 25 kW have been established at ICAR-Central Arid Zone Research Institute, Jodhpur, and its regional station at Bhuj, respectively, with a land requirement of 29 m2 per kW. Rainwater harvesting system from top surface of PV module has been designed and developed. The harvested water is expected to provide supplemental irrigation of 43 mm in 0.76 acre land on which 105 kW system has been established. Suitable crops for agri-voltaic system have been identified, which generally does not attain height not more than 50 cm during its crop growth period. Few of the selected crops are Vigna radiata (moong bean), Vigna aconitifolia (moth bean), Plantago ovata (isabgool), cuminum cyminum (cumin), etc.

The objective of this paper is to analyze the performances of different photovoltaic (PV) array configurations under partial shading condition (PSC). The array output characteristics for different PV array configurations: Series (S), Parallel (P), Series-Parallel (SP), Total-Cross-Tied (TCT), Bridge-Linked (BL), Honey-Comb (HC) and proposed hybrid configurations: Series Parallel-Total Cross Tied (SPTCT) and Bridge Linked-Total Cross Tied (BLTCT) are generated under uniform irradiance condition (UIC) and PSC analogous to a specific shading pattern in the presence and absence of bypass diodes. The analysis of the performances of all the aforesaid configurations has been accomplished by evaluating their maximum powers, fill-factors, and relative power losses for a specific shading pattern. The single-diode model of PV module is considered in this paper for modeling of PV module and array, and the overall procedure is implemented by MATLAB programming. The obtained programming outcomes of different PV array configurations give useful understanding regarding the performances of these configurations under PSC. The effect of varying temperature on different PV array configurations under PSC is also observed.

The hot spot phenomenon is a relatively frequent problem with solar photovoltaic modules (SPV). The module installations in the recent year are increasing due to different technical and commercial improvements; however, their inspection and maintenance requirements are likewise demanded. As the SPV technology installed on various residential and commercial buildings, safety issues are also the prime concern; it should neither damage the structures nor harm the residents. This paper undertakes a systematic compilation of a simple procedure to examine the faults in four solar module technologies, i.e., interdigitated back cell (i), hetero-junction intrinsic thin layer silicon (HIT), and multi-crystalline (mc-si) and mono-crystalline (m-si) silicon modules using infrared inspection. The infrared images are accepted up to 10 min to ensure the relevant results and thermal stress over modules. The distribution of the temperature was reported in the paper for all the four technologies, including two high-efficiency SPV modules.

In this study, we have synthesized metallic copper incorporated silver indium sulfide (AgInS2-Cu) nanocrystals (NCs) solvothermally by a unique method (hot injection method) to improve the photovoltaic performance of the base material, i.e., AgInS2 (AIS) ternary semiconductor NCs. Incorporation of metallic copper has been confirmed by the characteristic peaks of Cu(0) appeared at powder XRD pattern and also by clear dark spots found in the TEM images of the hybrid nanomaterial. Also, incorporation of copper induces redshift of the electronic spectra which facilitate the absorption of visible light. Experimental results indicate about ninefold enhancement of the solar efficiency for AgInS2-Cu (AIS-Cu) NCs compared to that of the pure hybrid nanomaterial. Photocurrent sensitivity and stability have also been examined by chronoamperometric measurements within a wide time range. Nyquist plots reveal the decrease in the resistance (Rct and Rs) values and increase in the charge carrier densities which indicate that incorporation of metal into the semiconductor helps to propagate the electrons of the semiconductor through the metal toward electrolyte, thus resulting in the improvement of its photovoltaic performance.

Based on the energy balance equation of semitransparent PV module, an improved analytical expression for solar cell electrical efficiency (ηc) and solar cell temperature (Tc) has been derived. Numerical computations have been carried out for New Delhi climatic condition for all weather conditions. It has been observed that there is an increase of 0.97% in the electrical efficiency of solar cell for New Delhi climatic condition in comparison with the results of the previous proposed model.

This paper describes the development of the dielectric-coated metal-integrated solar panel, which is lightweight and can be used as an alternative roofing material, which can harvest energy. The idea is to leverage the surface area of the roof and its exposure to the sun by generating distributed off-grid solar power. This type of structure can be used also for making solar energy-driven vehicle.

Cu2ZnSnS4 thin films were deposited using spray pyrolysis deposition technique. The effect of deposition temperature and film thickness on various physical properties of Cu2ZnSnS4 thin films was studied. The structural study using X-ray diffraction technique revealed that the crystallinity of films was improved on increasing substrate temperature and film thickness. Energy-dispersive X-ray spectroscopy analysis revealed near-stoichiometric film composition. The atomic force microscope images showed formation of smooth, compact and uniform Cu2ZnSnS4 thin films over substrate surface. The X-ray photoelectron spectroscopy characterizations confirm the oxidation states of the elements in CZTS as 1+, 2+, 4+ and 2− for copper, zinc, tin and sulfur, respectively. Energy band gap was estimated to be 1.56 eV, indicating that Cu2ZnSnS4 compound has absorbing properties favorable for applications for solar cell devices.

In the present work, a mathematical modeling of concentrated photovoltaic/thermal humidification and dehumidification (CPV/T-HDH) desalination plant has been modeled and presented to estimate the performance of the plant. A concentrating photovoltaic thermal is a type of photovoltaic technology which generates electricity and useful thermal energy form high-intensity sunlight focused by lenses and curved mirrors. The efficiency of PV panel drops with increase in cell temperature. In order to maintain the cell temperature at an optimum level, the excess heat or thermal energy was recovered by circulating water. The recovered heat energy was used in humidification and dehumidification desalination plant to generate distilled water from seawater. The performance of plant was analyzed for various solar radiation values (800 W/m2, 900 W/m2, and 1000 W/m2) in terms of cell temperature, PV efficiency, hot water temperature, electricity generation, distilled water production, gained output ratio (GOR), and energy utilization factor (EUF) of the plant. The coolant water flow rate in PV panel was varied from 300 kg/h to 400 kg/h at each solar radiation level. The work is aimed to make use of process integration to optimize the existing system performance. The highest overall efficiency of the CPV/T system is 88.40%. The optimum operating condition of the plant is 800 W/m2 and 300 kg/h. The plant EUF and GOR at optimum operating condition are 0.1593 and 3.01, respectively.

This paper presents CFD study of air-based photovoltaic thermal (PVT) system with forced circulation of air. A PVT system is a combination of photovoltaic and solar thermal system that simultaneously generates electricity and produces low-grade heat. Till now, huge research work has been carried out for the performance enhancement of PVT systems, though very few PVT systems are commercially available. The high overall cost of the PVT system, unavailability of long-term performance data, unawareness about the benefits of the PVT systems to the customers and production of low-grade heat are some of the important factors responsible for less availability of PVT systems in the commercial market. In this study, CFD analysis of PVT system has been carried out for its thermal performance enhancement using radiation model available in commercial software ANSYS Fluent. The temperature distribution at the PV surface and thermal efficiencies of PVT systems are compared with the experimental results available in the literature and found to be in good agreement.

Bismuth sulfide is a promising n-type semiconductor for solar energy conversion. In this work, we have successfully synthesized bismuth sulfide nanoparticles (Bi2S3 NPs)] from [Bi(ACDA)3] complex. The as-synthesized particles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and UV-vis spectroscopy. The prepared material exhibits a high absorbance coefficient, a low bandgap, and good disparity. Thus, prepared Bi2S3 material provides a new candidate for the fabrication of environmentally friendly and low-cost inorganic hybrid solar cells.

Photovoltaic (PV) module converts only a fraction of the incident irradiation to electricity, and the remaining is mainly absorbed into the cells raising the cell temperature as a consequence the efficiency of the cell drops. A PV-thermal (PV-T) system has been designed, fabricated, and investigated experimentally in the present work. To actively cool the PV module, a parallel array of channel with inlet and outlet manifold was built for uniform airflow distribution and connected to the back of the module. The experiments have been carried out with and without active cooling. The forced convective fan cooling provided with two types of cooling arrangement and each arrangement consists of two PV modules. In one arrangement below one panel, air channel provided which is made of conducting material and another panel is reference panel without cooling arrangement. Similarly in second case non-conducting material provided in the place of conducting material and other is same as a reference panel. The purpose of the present study is to improve the design of photovoltaic installations placed in roof applications by comparing the electrical efficiency of the PV module with and without cooling arrangement by varying the air channel duct material. This will ensure low operating temperatures which will reverse the effects produced on efficiency by high temperature. The electrical performance has also been investigated.

Silicon nanoclusters/nanocrystals (Si-NC) embedded in silicon carbide (SiC) host matrix is a promising alternative to high bandgap dielectric matrices for solar cell application. However, the formation of Si-NC is a challenge since silicon carbide nanoclusters (SiC-NC) are formed with greater ease in the SiC host matrix. In this context, this work focuses on analyzing the influence of process parameters (deposition and annealing temperature) to synthesize the silicon-rich SiC film (a-SixCy) for favoring Si-NC formation in the host matrix. In this paper, the Si-NC in a-SixCy is obtained by co-sputtering of SiC and Si targets at different deposition temperatures (Td) such as room temperatures 200 °C, 350 °C, and 500 °C. It is annealed at various temperatures and ambience such as vacuum (VA) and conventional thermal annealing (CTA). The structural and optical properties are investigated using spectroscopic ellipsometry, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and photoluminescence spectroscopy (PL). The refractive index varies between 3.3 and 3.7 which indicates the Si richness in the film. In FTIR absorption spectra and Raman spectra, change in intensity and position of Si-related vibrations varies depending on the excess Si incorporation. PL spectra show emission in the range of 412–440 nm that varies with different annealing and confirms the possibility of the Si-NC formation in the film.

This study explores the deposition and post-deposition treatment of TiO2 films in the context of using those films as electron selecting layers in diffusion-free solar cells. The passivation provided by TiO2 films is known to improve after annealing. Therefore, the effect of annealing on electrical performance of the films is analyzed in this study. The study reveals that annealing may lead to a formation of thin interfacial silicon oxide which may impede the transport of electrons to the desired contact. It is also noted that annealing does not contribute significantly to lowering of reverse saturation current, and the ideality factor values also remain the same. Interestingly, while annealing improves the lifetime, the same is not reflected in electrical behavior of diodes. A plausible explanation of this behavior is given on the basis of numerical modeling of the fabricated device. Finally using the as-deposited TiO2 film as electron collecting contact and MoO3 as a hole quencher, solar cells are fabricated with an efficiency of 5.52%.

The intrinsic nature of Cu2O to be p-type makes the n-type Cu2O formation difficult, thereby leading toward the heterojunction solar cells. The interface mismatching between Cu2O and the n-type layer in the cell limits its efficiency. Strontium titanate (SrTiO3) is an n-type semiconductor having minimal band offset with Cu2O and possess superior electric properties. SrTiO3 not only serves as an n-type layer in solar photovoltaic but also can work as a protective layer in Cu2O photoelectrochemical cell. Its conduction band lies in between the conduction band of Cu2O and hydrogen reduction potential. In this work, the synthesis of SrTiO3 via pulsed laser deposition (PLD) is discussed on the thermally oxidized Cu2O sheets. It is observed that Cu2O reduces to Cu in its equilibrium phase field during the deposition of SrTiO3 via PLD.

In today’s scenario of utilizing maximum renewable energy, thermal storage systems are making boon because renewable energy sources are intermittent and dilute source of energy. Thermal energy storage system provides us freedom to use energy (heat) to meet the demand at that particular instant of time. Therefore, packed bed solar storage systems are used to store solar energy when it is available and this stored energy is utilized further. In this work, an experimental study is carried out in a sensible heat storage packed bed to find the effect of large-sized perforated cylinders in void fraction ε = 0.35 keeping the elements in a staggered manner. Cylindrical elements of concrete with perforation ratio range from 0.4 to 0.6, and numbers of perforation 2, 4, 6 are used to find energy stored and thermo-hydraulic performance in the storage bed. The Reynolds number varies from 1200 to 3200. Thermo-hydraulic performance of storage bed was found maximum 0.19 at 0.6 perforation ratio at 6 perforations, while maximum thermal heat stored in the bed was found maximum of 5.22 MJ at 0.6 perforation ratio at 6 perforations.

Different local ionic configurations can be encountered in the long-time dynamics of yttria-stabilized zirconia (YSZ). In our previous work, we introduced a new theoretical framework to capture the effect of these configurations on oxygen ion movement in a coarse-grained sense, with which we can capture the effect of the local environments in YSZ on kinetic parameters. Here ionic diffusion in bulk YSZ is probed using microsecond long classical molecular dynamics (MD) calculations using another interatomic potential. The overall results obtained from a classical MD simulation are qualitatively similar to the ones obtained in our previous study employed. We show that the probability of finding O2−-vacancy (O2−-vac) pairs in a local environment affects the oxide ion movement. The average rates and Arrhenius parameters are found to be sensitive to Y3+ content in the local environment.

Latent heat thermal energy storage (LHTES) has been receiving considerable attention in recent years because of high storage density and isothermal phase transition. In this study, an analytical model has been proposed for prediction of solid–liquid interface and temperature during solidification of phase-change material (PCM) in a two-dimensional rectangular LHTES with horizontal internal plate fins and an imposed constant heat flux on the vertical walls. The results are compared with available one-dimensional exact analytical results and two-dimensional numerical results, and good agreement has been observed.

In this work, Cu2O thin films having a thickness of 1.5 µm have been deposited on FTO glass substrate by electrodeposition in aqueous solution using copper sulfate as precursor and lactic acid as an additive. Deposited cuprous oxide film showed good photoresponse with a current density of 0.95 mA/cm2 at −0.1 V vs RHE. Protective over layers of AZO and NiOx were deposited over electrodeposited Cu2O film to inhibit the photo-corrosion.

Under operating conditions relevant to polymer electrolyte membrane fuel cell (PEMFC), NixPt1−x is known to exhibit oscillations in Pt compositions with the layer position, which is crucial to the catalytic activity of the alloy material. For example, the outermost and third layers of NiPt3 are Pt-rich, whereas as the subsurface layer is Ni-rich. Using Monte Carlo simulations, we investigate the surface segregation behavior in the presence of solvent. An inversion in the segregation behavior can be observed as Ni content is increased, such that the surface becomes Ni-rich when x ≥ 0.6 compared to the bulk layer composition. A thermodynamic framework based on distribution coefficients is employed to elucidate this effect. The distribution coefficients have a value less than 1, which indicates Pt-enrichment at the surface for small x, increases to a value beyond 1 when x is large causing Ni atoms to populate the surface layer.

The metal–organic frameworks (MOFs) have the potential as hydrogen storage materials due to large surface areas and presence of binding sites. To further enhance H2 storage capacities of MOFs, crown ethers have been incorporated to improve the interaction energies between the framework and binding molecules (H2). Therefore, the present study deals with the structure and energy of complexes of H2 with crown ethers (dibenzo-12-crown-4 and dibenzo-18-crown-6) and alkali metal ion decorated crown ethers at the DFT level of theory. The binding energy of H2 with only crown ethers was shown to be positive and thus not suitable for adsorption. But, after decoration with metal, namely Li and K, the binding energy of H2 was seen to be negative indicating feasibility for H2 adsorption. Increase in binding energy indicates an increase in stability of the complex, and as such, catenated crown ethers have a much improved hydrogen storage capacity allowing them to hold more molecules of hydrogen. Also, the binding energies are greater for Li+ systems compared to K+ systems, thus showing it as a better catenating agent than the latter. Also, Li+ incorporated DB18C6 in the MOF moiety has shown favorable H2 binding compared to Li+ incorporated DB18C6. The present computational results thus suggest that Li+-crown ether might be incorporated within MOF to enhance hydrogen storage capacity.

Metal alloy nanoparticles (NPs) are important to several renewable energy applications, such as photovoltaic devices, fuel cells, and batteries. Mixing behavior and segregation of the metal species in the NP is crucial to govern the performance of the NPs. Segregation, mixing, and catalytic activity are strongly influenced by the nanoparticle size, composition, and temperature. Quantifying these effects within the NP requires with understanding thermodynamic and microscopic nature of species distribution within the NP. In this work, we show that these effects can be captured using a nano-thermodynamic model based on the distribution coefficients for a ternary alloy NP. Ternary alloy NPs are far more complicated than pure metal and binary NPs. We investigate the effectiveness of the nano-thermodynamic model in gaining the fundamental understanding of ternary systems AuPtPd and AuPtNi.

The enthalpy of formation of metal hydrides is estimated by van’t Hoff equation. Pressure-concentration isotherms (PCIs) at different temperatures are used to obtain van’t Hoff plots. Enthalpy of formation is an important input in simulation and performance estimation of metal hydride-based engineering devices. The absolute error in the measurement of enthalpy of formation depends upon the relative error of PCI measurements. The error in the estimation of this quantity depends upon the number of temperature points used for obtaining van’t Hoff plots and, temperature range and size of the range. In the present study, PCIs of MmNi3.5Co0.8Al0.7 hydride were measured in the temperature range of 20–240 ℃. The effect of number of temperature points, temperature range and size of the range on the estimation of enthalpy of formation is studied. The effect of the temperature range and size of the range are found to be more sensitive in the estimation of enthalpy of formation.

In the present work, polyaniline (PANI) electrode material is synthesized by simple electrodeposition method on stainless steel (SS) substrate. The crystal structure and morphological characterizations of the obtained electrode material were carried out by using X-ray diffraction (XRD) technique and field emission-scanning electron microscopy (FE-SEM), respectively. The FE-SEM micrographs show interconnected nanofiber network like morphology. The electrochemical properties of PANI electrode like cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) and electrochemical impedance spectroscopy (EIS) were studied in a 1 M H2SO4 solution as electrolyte. The maximum specific capacitance is 277 F/g at scan rate 5 mV/sec obtained from CV. The electrochemical stability of PANI electrode was investigated using CV for 500 cycles. The PANI electrode exhibits good cycling stability for 500 cycles at scan rate 100 mV/sec. From all the electrochemical properties of PANI electrode, it indicates that it will be promising electrode material for supercapacitor application.

In this paper, a reduced order model of latent heat thermal energy storage (LHTES) containing spherical capsules filled with phase change material (PCM) is presented. The numerical method is based on the two-temperature non-equilibrium energy equations for heat transfer fluid (HTF) and PCM coupled with the enthalpy method to account for phase change in PCM. The numerical model is validated with the experimental results reported in the literature. The effects of porosity, capsule diameter, and capsule thickness on the temperature of HTF at the outlet of LHTES for charging period are studied. It is found that the stabilization time can be increased with low porosity and low mass flow rate, whereas the capsule shell thickness negligibly influences the heat transfer process from HTF to PCM.

The work outlined here provides a method to synthesize Pb nanoparticle catalyst as sulfides (PbS) and its subsequent reductive transformation to an active Pb nanoparticle catalyst for electrochemical reduction of CO2. The ease of synthesis and stability of metal sulfide nanoparticles make this route especially attractive. Characterization tools such as XRD, SEM, EDX, TEM, and XPS were employed to analyze the structure, shape, bulk, and surface compositions of the catalyst both pre- and post-reduction. Formate production rates were observed at four different potentials, viz. −1.6, −1.8, −2.0, and −2.2 V vs Hg/HgO. The production rate was found to be the highest (0.1585 mmol/h) at −2.0 V.

In this paper, unrestricted melting of erythritol phase change material (PCM) is studied in a spherical reservoir to describe sinking effects on heat storage and heat transfer rate with nano-enhancement. The unrestricted melting leads to strong stratified thermal zones in the reservoir, and further nanoparticles’ presence modifies base fluid thermophysical properties which in turn alter the heat transfer and the phase change patterns. A macroscopic one-domain continuum model for the unrestricted melting of erythritol is developed. The complete set of conservative governing equations is solved employing pressure poisson equation (PPE) with finite volume discretization method. The homogeneous modeling approach is used to predict thermophysical properties of the nano-enhanced phase change material (NEPCM). The developed model is validated with the experimental results available in the literature. The unrestricted melting behavior of PCM and NEPCM is compared. The influence of nano-enhancement on the coupled fluid flow and heat transfer behavior is described. Further, performance indicators of PCM/NEPCM-based thermal energy storage (TES) systems, like sensible energy and latent energy content, are delineated in both cases to explore its potential in designing erythritol-based TES systems with nano-enhancement, in the medium temperature range of 100–150 °C.

Thippeswmay, Pavankumar Bhaskar, Abhinav Mondal, SomThe critical challenge in designing a thermal energy storage is enhancement of the heat exchange between the fluid and the stationary storage material. The aim of this study was to design a thermal energy storage for storing energy from hot air in a paraffin wax-based phase change material (PCM). A commercially available automobile air-cooled radiator has been used as heat exchanger between air to PCM due to high heat transfer coefficient. The air was passed through the inner micro-channels of the heat exchanger, and the heat exchanger was immersed in paraffin wax. The charging and discharging of the storage unit were studied. During the charging process, a temperature difference of 40–$$50\,^{\circ }\mathrm{C}$$ was observed between inlet and outlet air, which suggest high heat transfer from air to PCM. During the discharging process, a maximum temperature difference of $$13.5\,^{\circ }\mathrm{C}$$ between outlet and inlet air was observed. The outlet air was maintained at $$48\,^{\circ }\mathrm{C}$$ for 22 min. The average temperature difference between solid–liquid interface of PCM and air inlet was at $$10.6\,^{\circ }\mathrm{C}$$ during the discharge process. However, a uniform melting of PCM could not be achieved throughout the whole storage unit. Further modification of the compact heat exchanger with extended surface may lead to better performance of the thermal energy storage model.

In this work, a numerical study is performed to analyze the reaction kinetics and associated transport phenomena pertaining to the dissociation mechanism of salt hydrates (Epsom salt [MgSO4·7H2O]). During the dissociation process, the salt hydrate dissociates into a lower hydrate or an anhydrate and evolves water vapor. The chemical energy used for the process of dissociation gets stored in the lower hydrate or anhydrate in the form of bond formation internal energy. This energy can be recovered back either by passing water vapor through it or by extracting a heat flux, thus converting the stored chemical energy into sensible heat. For this, a macroscopic model of decomposition of salt hydrate has been presented by taking into account solid-state chemical kinetics, thermodynamics and associated transport phenomenon. Equations of chemical rate, mass and energy have been coupled employing a single domain continuum formulation and have been solved numerically for the process of diffusion. Subsequently, the influence of reaction kinetics on the heat storage and heat transfer behavior is described. Further, an energy analysis during the dissociation process is delineated. The model is able to predict temperature and concentrations of all the attendant species during the thermochemical dissociation reaction. The insights from the current study can develop a deeper understanding of the decomposition process and can be useful in designing thermal energy storage (TES) systems using salt hydrates.

Nanostructured CuO has been synthesized by surfactant-assisted chemical bath deposition (CBD) method. The copper foam has been used as conductive substrate for CuO deposition, which can be used as binder-free electrode for supercapacitor. Due to the addition of organic surfactant Triton X-100, there is tremendous change in structure, morphology, surface area and electrochemical property of copper oxide. The nanostructured CuO was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectrum (FTIR). Electrochemical performance was evaluated through cyclic voltammetry and galvanostatic charge-discharge techniques. The XRD peaks showed that monoclinic CuO formed. The SEM images revealed the formation of flower-like structure by connecting many nanosheets together by addition of Triton X-100. The FTIR graph confirms the formation of CuO. The binder-free electrode developed using this nanopetals flower-like CuO exhibits high specific capacitance of 150 F/g at scan rate 5 mV/s, and excellent power performance and cycling stability. This study revealed that morphology plays an important role in supercapacitor.

The energy crisis in the present scenario is the main motive force behind development of energy conservation opportunities, thermal energy from solar and various process industries has the opportunity to harvest the available energy. The existing materials possess relatively lower thermophysical properties which makes unsuitable for thermal storage application. To improve the thermophysical properties of phase change material, nanoparticles are dispersed. A bounded domain of square geometry was considered for the numerical study. The composite phase change material (Paraffin wax as base and copper nanoparticles as additives) has shown the enhanced thermophysical properties compared to base material at different volume fractions, but only up to certain limit. The nanoparticles improved the thermophysical properties only up to 5% loading and above this value, it showed the adverse effect on thermal energy storage applications. The presented results conclude composite phase change materials with optimum concentration have the great potential towards the energy conservation opportunities.

Sodium-ion battery is most alternative advanced technology for portable electronics devices. In our present study, we are dealing with a suitable cathode material for sodium-ion battery which can deliver high capacity as well as good stable cyclic performance. We prepared sodium vanadium phosphate (Na3V2(PO4)3) by the simple solvothermal process. The as-prepared electrode is characterized by X-ray diffraction (XRD) analysis, field emission gun scanning electron microscope (FEG-SEM). The cathode material gives very high reversible discharge capacity of 123 mAh g−1 at current rate C/6 and has a very good stable cyclic performance. After 50 cycles, we achieved a discharge capacity of 115 mAh g−1 with same current rate, almost 94% capacity retention.

In the current study, nickel oxide (NiO) nanoparticles have been synthesized via sucrose-derived carbon sphere as a soft template derived from the hydrothermal treatment of sucrose. The size of the carbon sphere template is around 2–4 µm, and the derived NiO varied in size between 40 and 100 nm. The derived NiO-coated CNF has been used to coat glass fiber separator which works by effectively blocking and activating the lithium polysulfide thus resulting in the high capacity as well as high Columbic efficiency. The modified NiO/CNF employed cells provided a reversible capacity of 461.11 mAh g−1 along with the high Columbic efficiency of 92% at the end of 50 cycles. The cells also displayed high reversible capacities of 1105.74 mAh g−1, 800 mAh g−1, 603.92 mAh g−1, 415.49 mAh g−1 and 742.9 mAh g−1 at the end of 0.05C, 0.2C, 0.5C, 1C and 0.05C, respectively. The modified separator with its electrostatic interactions of lithium polysulfide with functional groups of CMC binder and electronegative part of NiO nanoparticles combined with the high surface area of carbon nanofibers provides a promising design for developing high-energy lithium–sulfur batteries.

High temperature thermal storage in a packed bed is considered for air-based concentrated solar power plants. In this work, the performance of a high temperature sensible heat system has been analyzed using mathematical simulation. Heat transfer and fluid flow equations for a one-dimensional two-phase model has been discretized using explicit center difference scheme in space and Euler forward difference scheme in time. Discretized equations were solved to determine temperatures of different elements of bed, and corresponding temperature of air as a function of space and time coordinates. Temperature distribution of bed elements was utilized to obtain mean bed temperature and energy stored in the bed. These values were used to determine charging efficiency as a function of system parameters, namely void fraction and equivalent diameter. The extensive investigation of parametric effects of important bed parameters, namely element size, void fraction has been done in this work.

Three-dimensional mathematical model is developed and solved numerically for predicting the charging characteristics of MmNi4.6Fe0.4 based hydrogen storage device, using COMSOL Multiphysics 4.3a. This study investigates the transient heat and mass transfer phenomenon occurring during absorption of hydrogen by taking into account of pressure gradient between hydride bed and supply condition, diffusion of hydrogen and heat transfer between the bed and cooling fluid with emphasis on convective boundary condition. Using this model, charging characteristics of two cylindrical reactor configurations, each having 48 embedded cooling tubes (ECT) in a unique pattern, are predicted at the supply condition of 3.5 MPa and 298 K. One of the configurations is designed with an additional outer cooling jacket (OCJ). From the analysis, it is evident that ECT configuration highly influences the hydrogen absorption rate, which is further enhanced by OCJ. Due to inclusion of OCJ, average bed temperature dropped from 334.5 to 305.8 K within a span of just 200 s, while 80% of hydrogen storage capacity is achieved within 165 s and observed maximum storage capacity is 1.15 wt% within 800 s.

Micro-scale capacity organic Rankine cycle (ORC) is commercially unavailable in the Indian market due to cost effectiveness and unavailability of local manufactures. The present work is an effort toward manufacturing ORC test rig from the locally available components. In this paper, an experimental study of ORC test rig using low-temperature source has been presented. The experimental results show that the isentropic efficiency of the expander is in the range of 60–73%. The overall thermal efficiency of the cycle is calculated in the range of 2.5–4.8%. The levelized cost of energy for the developed ORC test rig is calculated 0.079 USD/kWh.

Solar heat gain through windows is a significant factor in determining the cooling load of buildings. External shading devices are extensively used in buildings to reduce the cooling load. However, use of shading devices reduces illuminance level inside the room which in turn increases the use of artificial lighting. A case study is carried out to study the impact of four different types of shading devices on solar gain, cooling load, lighting gain and illuminance level in four rooms facing west facade at hostel building located in coastal area near Mumbai. A computerized simulation tool (IES<VE>) is used to carry out the investigations. The results indicate that egg-crate and diagonal fins shading devices perform better compared to other shading devices. Peak cooling load is reduced by about 28% with egg-crate shading device with 500 lx illuminance level.

In the conventional thermal power plants, water-cooled condensers are used which need gallons of water to take away the heat from the low-pressure steam of the turbine exhaust. Due to scarcity of water in several regions of the world, water-cooled condenser (WCC) is not the viable option and hence can be replaced by air-cooled condenser (ACC). ACC leads to decrease in the plant efficiency by 5–10%, but still it holds greater importance in terms of reduction in water consumption to a greater extent. The current study computationally assesses the performance of axial fans used in air-cooled condenser for various pitch angles (PA) and speed ranging from 80 to 94.9 rpm. Air flow rate of the fan is found to be the maximum at pitch angle of 40.9°. All these studies are performed using the commercial CFD codes of ANSYS Fluent 17.1. This study attempts to lay down the foundation to use different fans in the ACC fan grid at their optimum operating conditions and find a greater relevance in future applications for the optimal design of the axial flow fans.

In the light of the current interests and policies in reducing the environmental pollution and global warming, nuclear energy is a strong contender to meet the energy needs of the country in a sustainable manner capable of providing clean and reliable energy for decades. Economic competence will also play a crucial role for the growth of nuclear energy in the country. Cost of electricity produced by a power plant is one of the most important factors in deciding its economic competence. Essentially, the cost of energy from the power plant shall be economically attractive and competitive to be able to contest with alternative energy sources. Levelised unit energy cost (LUEC) is often cited as a figure of merit of the overall competitiveness of different generating technologies. In this paper, the elements, which contribute to the economics of nuclear power plants, are brought out and a generic method is presented to evaluate Levelised unit energy cost, based on the discounted cash flow analysis. The method is illustrated by simulation and comparison of the economics of typical cases of nuclear, coal, gas, hydro, solar and wind power plants in India in the prevailing economic scenario.

The availability of potable water is one of the emerging challenges of the twenty-first century. This problem is more acute in arid, semi-arid regions, and population centers because of the continuous dropping of groundwater levels and increasing pollution of surface water bodies. In this regard, atmospheric water harvesting (AWH), i.e., cooling of the ambient air for moisture condensation is a promising alternative. AWH allows us to obtain clean drinking water in regions geographically far away from the sea, rivers, and other water bodies. Accordingly, it is necessary to develop relevant off-grid and environmentally friendly AWH systems. Here, we investigate the potential of a biomass gasifier-powered adsorption refrigeration system for AWH. We develop a thermodynamic model to estimate the water harvesting performance of this adsorption-based AWH system. Ambient climate conditions and crop residue availability in various developing countries are considered to quantify the AWH potential of this system. We show that the proposed AWH system can satisfy the potable water requirement (drinking and cooking) of around 19, 16, 12, 4, and 7% of the populations in Sri Lanka, Bangladesh, Pakistan, Nepal, and India, respectively.

The paper presents a new design of a solar tree where solar panels are appropriately positioned like the leaves of a tree. Compared to fixed orientation solar panels, the main advantage of a solar tree is the ability to optimize the orientation of individual solar leaves in order to tune the power generation curves as required, for example, increasing the energy production during the winter months when solar insolation is low. Since orientation of solar panels is the key to achieve the maximum productivity of solar photovoltaic (PV) plants, data-driven and location-specific approach is employed to determine optimal orientation of five solar panels for solar tree structure for seven locations covering a large latitude range. Compared to the commonly employed latitude tilt orientation for solar PV modules, optimal solar tree design shows the feasibility of tuning the power generation curves to increase the power production in winter months or any other desired months. Scope for such tuning is higher for locations having high direct normal irradiance (DNI) and high standard deviation in the solar insolation curve. Also, higher number of solar panels in a solar tree provides higher degrees of freedom and hence larger flexibility to tune the power generation curve.

In this work, we develop a framework to estimate region-wise, crop-wise electricity usage for irrigation using secondary datasets. The main secondary datasets considered were electricity consumption in agricultural feeders, Minor Irrigation Census data for water sources, Groundwater Survey and Development Agency data on well depth, theoretical crop water requirement from various sources, cropping area and rainfall recordings from the Department of Agriculture. Three case studies on an area each in Nasik, Nanded and Kolhapur district of Maharashtra were done to verify the efficacy of the framework at the village level. In these cases, we find that the amount of irrigation water used by farmers largely abides by the theoretical requirement. Hence, the cropping pattern and total electricity used in a region, whether at feeder level, taluka level or district level, can be used to find average energy consumption per acre by a particular crop within that geographical boundary. We find that farmers use water sources in many indirect ways which complicate their use in the framework. Also, the secondary data on water sources is unreliable; hence, water heads and sources cannot be used to calculate energy usage. The method developed here can be used in states with a dominant number of irrigators supplied by agricultural feeders.

The present study investigates the performance of two-bed adsorption refrigeration system for various types of activated carbon–ammonia pairs by employing steady-state thermodynamic model. Two performance parameters, namely coefficient of performance (COP) and specific cooling effect (SCE), are evaluated and compared for different types of activated carbon particles under various working conditions. The control parameters to depict variable working conditions are chosen to be maximum desorption temperature, minimum adsorption temperature, condensation pressure and evaporation pressure. A simple thermodynamic model has been developed to obtain the cycle analysis. Heats of adsorption and desorption are estimated using the Clausius–Clapeyron equation, while the Dubinin-Astakhov (D-A) adsorption model has been used to correlate concentration of ammonia (W) in the adsorber/desorber bed with respect to pressure (P) and temperature (T) under equilibrium condition. The theoretical analysis shows that activated carbon–ammonia adsorption refrigeration system can achieve COP of 1.4 and SCE of 240 kJ/kg at maximum and minimum bed temperature of 185 ℃ and 22 ℃, respectively, for compact AS12 activated carbon ammonia pair. The result of this simulation will provide convenient guidelines for the design of a two-bed continuous type basic adsorption refrigeration cycle.

Solar photovoltaic (SPV) pumps for irrigation are being used widely across the world for various reasons like increase in green energy, reduction in diesel usage, and a reliable source of energy to provide livelihoods to farmers. In this work, we develop a framework based on secondary datasets, to determine appropriate pump sizes and characteristics for a district to address the needs of the appropriate demographic of farmers. We conduct primary surveys in two districts of Maharashtra (Akola and Buldhana) where the government has implemented an SPV pumps scheme to verify the efficacy of the framework. We find that the pump sizes being promoted are quite large and under-utilized by the typical small farmer. Through this same framework, we also determine the seasonality of unused energy that could be fed back into the grid by net metering. The framework could be used to determine seasonal tariffs that encourage water efficiency, yet prevent gaming. We analyze the current SPV pumps scheme being implemented in Maharashtra.

Government of India (GoI) had a target to provide 24 × 7 electricity supply to all residential consumers by March 2019. Along with the electrification of all the households, load shedding is being removed for residential consumers in Maharashtra state. It is essential to understand the effects of change in supply availability on the feeder parameters due to recent policy changes. This study undertakes the analysis of rural residential feeders under three substations of Maharashtra state in India (where load shedding is removed from June 2015). The paper analyzes the feeder parameters such as electricity consumption, all types of interruptions (duration and frequency), aggregated technical and commercial (AT&C) losses, and bill collection efficiency with respect to change in electricity supply availability. Statistical tests were conducted to see the changes in AT&C losses, mean consumption, and bill collection efficiency for the periods with and without load shedding. This study intends to reflect upon the impacts of reliable electricity supply and its effects on feeder parameters. It is observed that both seasonality and availability of supply affect residential electricity consumption, while variation in AT&C losses and bill collection efficiency is region (substation) specific.

In this study, we investigate the association of building energy consumption with the site-based airflow characteristics in three different spatial configurations of buildings in low-income tenement housing, with the form factor and compactness ratio of the buildings remaining constant. Energy simulations were performed for each of the building layout types, and site-based airflow characteristics were calculated using steady-state Reynolds Averaged Navier Stokes equations with standard k–ε turbulence model on hexahedral computational grids. Simulation validation was performed using data acquired through an environmental sensor. Results show that the layout of the building had no impact on the annual building energy consumption. However, the variation of the plan did vary the air exchange rates through wind-driven natural ventilation, glazing health gain and the operative temperature. It indicates a probable difference of thermal comfort ranges with the change in the layout of these low-income tenement houses. Future work lies in quantifying these factors regarding energy conservation measures and prepares a guideline for urban renewal and rejuvenation of this low-income neighbourhood.

This study explores the ubiquitous links between human behavior and perception of first-generation green buildings in India. It is generally assumed that similar rated green buildings should invoke similar levels of user satisfaction. However, this remains significantly under-researched in case of India’s first-generation green buildings. The level of user experience and perception is studied through a five-point occupant questionnaire survey across three similar green-rated office buildings in India. The case study buildings are located in Delhi-NCR and lie in the same climatic zone. Twenty-five attributes related to user satisfaction are taken into consideration. The questionnaire responses are statistically analyzed using data reduction method of factor analysis to understand the latent variables that affect human experience. The results indicate that there is significant non-uniformity in the user experience and perception. The study suggests that human behavioral aspects should be considered in the design process as only physical attributes and environmental factors may not be sufficient to evaluate the performance of a green building. The broader aim of the study is to create higher acceptability of green buildings among the users that would enable across urban sectors.

Bangladesh, the eighth most populous country in the world, is facing an acute problem in managing the energy demand. Its gas reserve, on which it has been dependent for years, is depleting. However, the energy demand will keep on increasing as Bangladesh has already set the goals to become a higher middle-income country by the year 2021 and a high-income country by 2041, with per capita electricity consumption of 600 and 1500 kWh, respectively. Although the annual greenhouse gas (GHG) emissions of Bangladesh are quite low (0.37 tCO2 / capita / year), Bangladesh is one of the most vulnerable countries to the impacts of climate change. According to the Intended Nationally Determined Contributions (INDC) submitted by Bangladesh, it is committed to reduce GHG emissions by 5% (with respect to the base year 2011) from business-as-usual levels by 2030. However, it is planning to have 35% coal-based electricity generation by 2041, resulting in 400% increase in GHG emission from power sector alone. In such context, this study examines the current energy plans in Bangladesh (Power Sector Master Plan, i.e., PSMP 2016) and proposes an alternative energy mix for the next couple of decades.

Some of the highest solar insolation regions of the world are in the arid and semi-arid zones. These zones have seen large-scale deployment of solar power plants during the previous decade. Data quality analysis of solar radiation information from various sources is significant in this context. Semi-arid zones have large number of clear-sky days per year but are also subjected to other micro-climactic events. All the three components of solar radiation change during these events. The gaps in the solar radiation data sets need to be filled appropriately to obtain a continuous time series that can be used for solar resource assessment and forecasting. A review of the gap-filling techniques and their application to a semi-arid zone solar radiation data set is presented in this work. Further, it is pointed out that various cloud conditions need to be considered while gap filling for a better assessment of bankability of a solar power project.

Simultaneous use of more than one type of renewable energy source known as Renewable Hybrid Energy System (RHES) is becoming limelight these days. Due to the presence of multiple sources of energy in RHES, the overall timely availability of energy production increases. However, the optimum sizing of the RHES is very important for cost-effective energy supply and overall reliability. This paper gives an account of a basic model for the optimization of RHES, its economics and summarizes the initial evaluation.

Energy conservation is the need of the hour in the world and more so in India, not only due to energy imports and energy security concerns but also due to growing concerns of its environmental implications. Indian Railways (IR), the nations transport lifeline, is one of the nation’s major energy consumer and is passing through a difficult financial state due to high operating costs of which energy is one amongst them. Carriage Repair Workshops (CRWs) in IR undertake Periodical Overhauling (PoH) of coaches and are major consumers of energy in various forms, viz. petroleum diesel and electricity other than traction applications. CRWs were established in pre-independence era and over the years they have successfully implemented many state-of-the-art energy conservation measures (ECMs) using the latest technologies available globally. This study focuses on two CRWs both located in the south Indian state of Karnataka, one at north part of Karnataka, i.e. Hubli and the second one at Mysore which is in south Karnataka which are into PoH of coaches since several decades. The study delves into two aspects, viz. the drives which have promoted the ECM and the barriers which are impeding the implementation of ECM. Prioritization of barriers helps in focused attention and efforts in the process of overcoming them. The stakeholder’s perspective in any such prioritization scheme is essential and also rewarding. It is observed that the attrition rates in railways are very low and as such most of the employees have vast experience in the organization. To take advantage of the same, the main stakeholders (officers and engineers) of CRWs are interviewed and the various dimensions pertaining to drivers and barriers are collected by face-to-face interviews. Totally 124 respondents which comprise of one-third of the population including both the CRWs were involved in the study. Questionnaire was developed to rank the drivers and factor analysis approach was adopted to group the variables representing barriers into manageable factors and rank them. Forced ranking method was employed to rank the drivers and factor scores for prioritizing the barriers. Five-point Likert scale was used to measure the stakeholder’s perceptions regarding the 25 barrier dimensions in the factor analysis. The study revealed that topmost driver for ECM was “the drive by the workshop management” and the topmost barrier factor was “motivation of employees”. This underscores the need for policy reforms by IR for aggressive implementation of ECMs in CRWs for fruitful results in the years to come.

Power grid is a common platform connecting all the generating stations and demand centres (loads), where the energy is generated and consumed instantaneously. The demand varies from minute to minute, and the generation needs to be adjusted accordingly to meet the demand. However, with large intermittent renewable power plants coming online, this balancing becomes even more complicated. Although there is a growing emphasis on predicting the renewable generation, prediction of demand also can help in grid-level energy management. In this paper, we compare the prevalent demand forecasting practice with the model developed using multivariable regression technique. This simple model shows an improvement of 3% over the present demand prediction scenario, with respect to the mean absolute error. In future, use of more precise data for model training and addition of further variables may increase the accuracy level. This model does not need any large computational set-up or capacity building. We have used electricity demand data of Karnataka to train and test the model. However, it can be replicated for any other state.

High temperature and corrosion are the challenging obstacles for any device to be used for molten salt flow measurement. Existing flow measuring devices have limitations due to operating temperatures above 550 ℃, corrosion, maintenance, and high cost. We have introduced a simple and economical method of high-temperature flow measurement which involves measuring the time interval between changes in temperature of successive K-type thermocouples. The device is calibrated using cold and hot water, within the selected range of temperature 30–80 ℃, and the non-dimensional thermophysical properties of molten salt and water are nearly matched. The results obtained show the device is capable of measuring the flow rates with less than 10% error.

Nambram, Sushibala Jana, Arnab Narayanan, KrishnanEnergy efficient building design measures can reduce the building energy consumption significantly. In the warm and humid climatic zone, energy consumption for maintaining the thermal comfort level is the major contributor to the building energy consumption. This study explores the energy consumption reduction potential of energy efficient building design measures by varying combinations of the different building envelopes, window to wall ratios, orientations and system components of building energy system. The objective of simulation study is to assess the potential energy saving and emission reduction of Energy Conservation Building Code (ECBC) if applied to a residential building operating in a mixed mode in the context of urban redevelopment schemes in Mumbai. 12.24% reduction in energy consumption was achieved by adopting ECBC compliant energy efficient building envelope design. Further reduction of 16.61% was achieved by selection of appropriate Heating, Ventilating and Air Conditioning system, optimization of daylight and occupancy load using control systems, use of higher efficiency appliances and reducing operating hours. The results show substantial energy savings and the need for future residential building under redevelopment to be brought under the purview of ECBC, if our sustainable development goals of 2030 are to be achieved.

A novel multi-utility, medium temperature, seasonally tracked, concentrated solar technology-based collector with absorber integrated heat storage is developed and tested in Heat Pump Laboratory at IIT Bombay. This solar collector can be used for different applications such as water heating, steam generation, cooking and liquid desiccant regeneration. Theoretical and experimental performance of the novel solar thermal collector as a one through water heater is presented in this paper. Theoretical analysis of the evacuated glass-based solar collector shows the optical efficiency to be 62%. The five solar collector panels, 1.42 m2 each, were connected in series and were used for once-through water heating. Water was heated from 30 °C to above 95.4 °C. Weighted average efficiency of 55 ± 1.7% was recorded over 6 h periods, for average global insolation of 800 W/m2 and ambient temperature of about 30 °C. Absorber integrated heat storage enabled generation of hot water even after sunset. The solar thermal collectors have already been deployed for solar cooking and will be used for regeneration of liquid desiccant in a solar air-conditioning system in the near future.

Despite the evolution in cooking practices over the globe, a large population still relies on traditional cooking practices, such as wood-fired cookstoves or “chullahs”. Though the fuel is locally available, the collection of wood is time consuming and tiring. An increase in the efficiency of the “chullahs” reduces the wood consumption and saves the effort of wood collection. Various techniques have been introduced in order to reduce the amount of fuel by improving the thermal performance of the “chullah”. It is experienced that the minimally retrofitted traditional “chullahs” have better acceptance among the users than the ones which are completely differently designed. The objective of the present work is to test one such traditional chullah and investigate the scope of improvement of thermal performance with minimal modifications in the actual stove or in the cooking practice. To achieve that goal, a traditional cookstove from the Kaiyal village of Kadi block from the Mehsana district of Gujarat is selected. Experiments are performed in order to identify the sources of heat loss and to find out the best modification. Water boiling test is carried out for the measurement of thermal performance. The efficiency is found to increase by 37.18% as compared to the original cookstove with an increase in the base height and insertion of twisted tapes.

Integration of CO2 capture and storage (CCS) with biomass-based energy production can play a vital role in reducing greenhouse gas (GHG) emissions by achieving negative emissions of CO2. This paper analyzes two key bio-energy pathways, ‘biomass gasification-based hydrogen production’ and ‘anaerobic digestion for biogas production’ for their integration with CO2 capture (CC). Each of these pathways has been analyzed based on the available literature so as to compare the following parameters: pre-combustion CO2 captured per unit of energy production, fraction of total carbon captured from the biomass feedstock, cost of energy production with and without CC and cost of CO2 capture. It has been found that biomass gasification-based H2 production offers a possibility to capture the majority of CO2 on pre-combustion basis itself. While bio-CNG production is a pathway with a relatively lower cost of energy production and lower cost of CO2 capture as well, it offers a significantly lower amount of CO2 available to be captured on pre-combustion basis.

The effect of three different thermal boundary conditions on fluid flow, entropy generation and heat transfer is analyzed for natural convection in a closed square porous cavity. The generalized lattice Boltzmann method (based on Brinkman–Forchheimer-extended Darcy model) is used to simulate the flow through the porous medium. The three different cooling arrangements are made at the vertical walls of the cavity via uniform, sinusoidal and linear temperature distributions while maintaining the bottom wall uniformly heated and the top wall thermally insulated. The comparison is carried out with existing published results to lend legitimacy to the findings. Numerical simulations are carried out for the range of Rayleigh number (Ra) from 103 to 105 and Darcy number (Da) from 10−1 to 10−5 with porosity (ε) at 0.5. The volume fractions ($$\phi$$) of Cu nanoparticles in water are varied from 0 to 5% to check the influence of nanofluid on the enhancement of heat transfer efficiency. The entropy generation minimization (EGM) approach, based on heat transfer rate and entropy generation, is implemented in order to make a judicious choice of boundary condition in terms of energy efficiency. The results indicate that the selection of optimum boundary condition depends on the values of Ra and Da.

In this paper, the techno-economic feasibility and environment impact of CdTe- and micromorph-based PV technologies has been assessed. The CdTe- and micromorph-based grid-connected PV systems have been simulated on PVsyst software including thermal, electrical, optical losses, and inverter losses. The yearly energy generation from the system is used to determine the discounted payback period and levelized cost of electricity (LCOE) incorporating the yearly degradation rate of the system. The viability of CdTe- and micromorph-based system has been compared with conventional wafer-based multi-crystalline silicon PV technology. The impact of deployment of thin-film PV technologies on environment has been investigated. The embodied energy and CO2-equivalent emission of thin-film PV system have been determined. The carbon footprint, energy payback time (EPBT), energy return on investment (EROI), and CO2 mitigation of CdTe- and micromorph-based thin-film PV technologies have been evaluated for Indian conditions. A comparison of environmental impact of these technologies with multi-crystalline silicon PV technology has been presented.

This paper is an attempt to improve the heat transfer coefficient of a rectangular plate fin through a milling process called knurling. In this study, different types of knurling that can be done on rectangular plate fins are analysed. These fins are modelled using Solidworks and the simulations of various conditions are run on ANSYS Fluent. All the fins have equal mass as the comparison is primarily based on the idea of subjecting rectangular plates of equal thickness and breadth through different types of knurling, where the length of fins varies. It is assumed that forced convection heat transfer takes place in a channel of rectangular cross section and the flow is turbulent. Heat transfer coefficients of knurled fins are compared among themselves and with plain rectangular fin while varying the air flow velocity through the duct. Consistency of the values is verified by varying the base temperature of the fin and the channel.

In the present situation, energy segments and industrial visionaries can pick another method for control age utilizing the most liberally accessible inexhaustible wellspring of vitality as biomass squanders. Among the biomass assets, coconuts are the copious inexhaustible asset of vitality accessible all around the globe. The novelty of this work is to imagine an approach of producing electricity by intermediate pyrolysis and to acquire a more yield of pyrolysis liquid (bio-oil) that easily can be utilized as value-added bio-fuels. Pyrolysis is defined as thermal decomposition of organic material which decomposes at elevated temperatures (500–600 °C) in the absence of oxygen. Solids, liquids and gases are the end products.

Jain, Manisha Rao, Anand B. Patwardhan, AnandMandatory labelling and periodic revision of efficiency standards have improved the energy efficiency of room air conditioners in India. The impact of standards on the incremental price of efficiency is not well understood due to fragmented data on retail price and energy efficiency. In this study, the incremental price of efficiency for room air conditioners in India is estimated before and after strengthening of efficiency standards. The results show that there has been a decline in the incremental price of efficiency in 2016–17 as compared to 2012–13 despite strengthening of efficiency standards in 2014.

In this study, the experimental analysis of concentric tube heat exchanger has been done with synthesized zinc oxide nanofluid. Zinc oxide nanoparticles were prepared by polymer precursor method characterized by SEM and X-ray diffraction. These nanoparticles were dispersed in DI water with varying volume concentrations (ɸ = 0.02–0.1%) with acetylacetone as a surfactant for stability and complete dispersion. In this experiment, the inner side flow rate maintained constant with DI water and from the outer side, nanofluid flow rate varied between 40 lph and 160 lph. The actual heat transfer and overall heat transfer coefficient were calculated for each concentration. Because of enhancement in the thermo-physical properties of nanofluid, it shows promising results on the overall performance of concentric heat exchangers.

Access and availability of modern energy resources such as electricity are crucial for the quality of life. The present study traces the contours of inequality of access to electricity and its consumption at the household level using the data from population census of 2001 and 2011 and three different survey rounds of the National Sample Survey Organization (NSSO), respectively. While the census data allow us to map the contours of inequality spatially, the panel data from the NSSO surveys allow us to trace this inequality among different groups by economic deciles within and across states. It is pertinent to mention that the electricity consumption at the household level and the economic prosperity as inferred from average monthly per capita expenditure (AMPCE) shows a significantly robust log-linear relationship. The study explores inter- and intra-state inequality in residential electricity consumption and the spatio-temporal transition of the Gini coefficient across the states. The timeseries data bring out two major concerns—the persistence of inequality within and across the states and the significant uneven consumption between the top and bottom deciles. This opens up different pathways for moving towards a regime of better electricity access and low inequality and insights to policy.

The heat transfer characteristics along with pressure drop inside a rectangular channel embedded with pin fins are numerically and experimentally investigated. The geometry of the problem, meshing, and models have been solved by ANSYS Fluent 17 solver to find the optimum pin fin shape based on maximizing the heat transfer. Several geometrical shaped pin fins (i.e., circular, square threaded, and helix grooved) with the identical cross-sectional areas are compared in staggered arrangement. The Reynolds number is varied from 13,500 to 42,000 with the clearance ratio (C/H) 1 and the inter fin spacing ratio (Sy/D) 3.417. An adiabatic thermal condition is applied to the side walls of rectangular channel and a constant heat flux 3200 W/m2 condition is applied to the heated aluminum base plate. The thermal performance analysis is made under constant air supply by air blower at inlet. Nusselt number and Reynolds numbers are considered as performance parameters. The experimental review shows that the modifications with square threaded and helix grooved geometries produce blockage to fluid flow which increases turbulence within a channel and lead to heat transfer enhancement and pressure drop. The result of staggered configuration and different geometries are also compared with the result of pin fins with solid cylindrical geometry. In terms of pressure drop and heat transfer, the square threaded cylindrical-shaped pin fin is a promising alternative configuration to conventional geometrical shape pin fins.

This paper describes the extension of CREST’s popular and open-source domestic energy demand model for UK households into one that can also model households in India. The model is based on a representation of individual appliances and their usage, dependent on ‘active occupancy’, meaning the times that people are both at home and awake. The model is well suited to the analysis of low-voltage networks and micro-grids, for which its ability to account for demand diversity is of critical importance. Energy consumption in households in India is quite different from that in the UK. Several functional extensions are required in order to represent features that are significant in India. The per-household ownership of appliances and lighting fixtures is currently much lower in India than in the UK. The model represents both urban and rural locations and the expected increase in appliance ownership in India. In India, the model shows that domestic demand profile is currently more heavily dominated by an evening peak of demand.