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Abstract In building integrated photovoltaic (BIPV) systems, PV elements are integrated along with the building which often serves as the exterior weathering skin. PV researchers from various countries have been working for several years to optimize these systems. Sustainable BIPV system has many benefits such as the building itself becomes the PV support structure, and the BIPV components displace the conventional building materials and labor cost, thereby reducing the net installed cost of the PV system and building construction. It also provides on-site generation of electricity and architectural elegance, which increases the market acceptance of the buildings. The BIPV systems can be interfaced with the available utility grid or used as off-grid systems. This paper identifies sustainable building concept in South Asian countries and role of BIPV applications in sustainable building. This article gives review of BIPV applications in South Asian countries. Finally, Barrier and challenges of BIPV system have been discussed and future direction is highlighted.

Abstract Energy rating of PV module as per the site-specific climatic condition is essential for customer’s point of view to choose suitable PV technologies. For site and technology-specific energy rating of PV module, it is essential to design standard datasets for it. In this paper, energy ratings of three different technologies with the data sets based on the angle of incidence, spectrum, irradiance, wind and temperature using existing formulae has been reported. The performance surfaces of PV technologies are designed based on the IEC 61853-1 & 2, and IEC 60891. A procedure is reported to including the degradation rate in the energy rating method. Comparisons of energy rating of amorphous silicon, HIT and multi-crystalline silicon using the existing method considering the degradation rate are done with the measured data. It has been observed that all the three technologies at Cold & sunny zone shows the highest energy rating. A procedure, to find out the most frequent conditions in terms of occurrence probability for different PV technologies is also reported.

Abstract Recently a simple explicit model was introduced to represent the J–V characteristics of an illuminated solar cell with parasitic resistances and bias dependent photocurrent as j = (1 − vm)/(1 + αv), here the normalized voltage, v and normalized current density j can be represented as v = V/Voc and j = J/Jsc respectively, where Voc is the open circuit voltage and Jsc is the short circuit current density. The model is an equivalent rational function form and useful for design, characterization and calculation of maximum power point voltage. The model is intuitive and lacks the analytical support. In this paper an analytical derivation of the model is presented using the physics based implicit J–V equation.

Abstract Quantum efficiency and impedance spectroscopy tools are employed for understanding the influence of parasitic absorption losses and partial field effect surface passivation by the silver nanoparticles (Ag NPs) on electrical properties of textured silicon solar cells without and with Si3N4 spacer layer. The parasitic absorption losses from Ag NPs reduced the internal quantum efficiency near the surface plasmon resonance region. The passive components like; series and parallel resistances, chemical capacitance of solar cells without and with Ag NPs are estimated after fitting impedance semicircles, which are further used for estimating effective carrier lifetime (τeff) values. Under AM1.5G illumination, cells with Si3N4 spacer layer showed a large decrease in the τeff due to the strong parasitic absorption losses from the Ag NPs. But, the cells without Si3N4 spacer layer showed a small decrease in the τeff due to the reduced surface recombination after partial field effect passivation from near-fields of Ag NPs’ surface plasmon resonances on the emitter surface.

Abstract Thermal annealing is an important process to improve the power conversion efficiency (PCE) of bulk-hetero junction organic solar cells (BHJ OSCs) by inducing micro-structural changes within the active layer blend’s constituents leading to amelioration of charge transfer/transport dynamics and interfacial properties. This work investigates the impact of thermal annealing on the photovoltaic performance ofPoly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]] (PTB7):[6,6]-Phenyl C71-butyric acid methyl ester (PC71BM) (PTB7:PC71BM) thin film blend in the presence of DIO (1,8 –Diiodooctane) additive, at different annealing temperatures (40, 60 and 80 °C) and correlates with the performance of DIO-free devices investigated under similar annealing conditions. Our results show that DIO-containing (w/DIO)blends, annealed at moderate temperature (40 °C) for 1 h exhibit significantly improved short circuit current (Jsc)as well as fill factor (FF) and hence 25% improvement in PCE over bench dried (unannealed) DIO-containing blend films. Interestingly, thermal treatment of DIO containing blend films at a higher temperature of 80 °C results in significant reduction of FF. However, for without DIO (w/o DIO) devices, FF remains unchanged while decrease in Jsc is significant. The inferior performance of both (w/DIO and w/o DIO) the devices at higher temperatures ~80 °C emanates from an unfavorable distribution of the polymer- fullerene network, as shown by morphological and surface potential analyses. Specifically, in w/DIO devices, the decreased performance is possibly induced by the temperature driven, accelerated loss of DIO additive that produces the evolution of undesirable morphology thus deteriorating the performance.

Abstract This paper reports an experimental study on the performance characteristics of four solar air heaters. Two were of a corrugated type and two were of a mesh type. All used ordinary black-painted surfaces. Instead of comparing the efficiencies at the same rate of discharge, the same amount of pumping power was employed so that the unequal frictional losses were also taken into account in the comparison of over-all heater efficiency. The rating parameters, such as plate efficiency factor, heat-removal efficiency factor, over-all heat-loss coefficient, and the effective absorption coefficient have been reported for average winter conditions for these heaters at Roorkee, India. The air-heater performance can be computed from these parameters for any other usual range of operating conditions.

Abstract Conventional maximum power point tracking (MPPT) algorithms fails to track peak power from a solar photovoltaic panel (SPV) effectively under rapidly changing atmospheric and partial shading conditions (PSC). To track peak power more effectively under these conditions, low cost, powerful soft computing (SC) have been introduced by the researchers. Due to the ability to solve non-linear problems, flexibility and adaptive nature, SC based MPPT techniques can track peak power under varying atmospheric conditions. Various SC based MPPT techniques have been proposed by researchers till date. Comprehensive studies on all these techniques are not available. This work summarizes working principle of various SC-MPPT techniques and are compared each other based on the certain parameters like accuracy, tracking efficiency, SPV array dependency, convergence time, complexity of algorithm, hardware implementation, ability to handle PSC’s and variables used. The information that is gathered and summarized in this paper will help researchers for future studies in this area.

Abstract Hybrid photovoltaic thermal systems consisting of solar panels and solar thermal absorbers are generally used for improving the electrical and thermal efficiency of the photovoltaic panel by cooling. Thus, thermal energy produced can be used for other applications. Depending on solar insolation and location, building integrated photovoltaic (BIPV) systems are designed and developed to fulfill energy needs. This paper reviews the detailed study on the effect of the front surface, back surface and combined front and back surface cooling on the water-based photovoltaic systems. This paper also discusses different designs of solar thermal absorber collectors. The front surface cooling resolves two problems. Firstly, it significantly reduces the PV panel temperature by 22–27 °C depending on the cooling phenomena used and secondly, it cleans the PV panel, thereby increasing the optical efficiency. The PV panel temperature reduction (5–6 °C) in the water spraying cooling system is more than water flowing over the front surface. The photovoltaic thermal absorber collector system is the most economically viable system from the electrical and thermal energy generation perspectives. The evaporative cooling on the backside of PV panels using clay and cotton wick structure could be an effective solution for a standalone PV system. It is observed that dual cooling is suitable for PV panels cooling in a hot arid region but needs further investigation. Finally, the environmental impact and economic feasibility of water-based photovoltaic cooling systems are discussed.