Advances in Solar Power Generation and Energy Harvesting

The light coupling and scattering property of silver (Ag) nanoparticles (NPs) depend on Ag NPs’ size, shape and interparticle distance of adjacent Ag NPs on the respective silicon (Si) substrate surface. In this Ag NPs’ arrangement onto the Si surface, least surface coverage is always required to minimize the parasitic resistance and enhance light transmission into Si layer which helps to enhance Si solar cell efficiency. In this work, fabrication and optimization of silver (Ag) nanoparticles onto the polycrystalline silicon (pc-Si) have been discussed for enhancing light trapping into Si substrate. Silver NPs of different sizes have been fabricated by using rapid thermal annealing (RTP) of RF deposited Ag thin film on pc-Si surface at RTP temperature of 200, 250, 300, 350 and 400 °C for various annealing durations. A shrinkage force generated at the interface due to the difference in thermal expansion coefficient between Ag thin film and pc-Si surface is responsible for the formation of these Ag NPs. The magnitude of RTP temperature and amount of RTP heat treatment helps in reshaping of Ag NPs, and accordingly, surface coverage by Ag NPs changes onto the pc-Si surface. Experimental results show that minimum surface coverage of 12.17% can be achieved at 400 °C for 35 min RTP treatment which can be utilized for enhancing light trapping property into Si surface.

The optoelectronic and electrical properties of zinc oxide (ZnO) nanostructures are dependent on the morphology and dimensions at the nanoscale. The present work explains different methods to grow zinc oxide nanostructures to be applied in dye-sensitized solar cells (DSSCs). The importance of aligned nanostructures of ZnO has been described with advantages specific to DSSC applications. The aligned ZnO nanostructures are generally helpful in reducing recombination instances and faster electron collection rates when used as photoanode in DSSCs. This helps to enhance short-circuit current density and open-circuit voltage which result in increased efficiency of the devices. The significance of optimization of the thickness of the photoanode has also been explained to achieve these advantages.

Phase change materials (PCMs) have been widely investigated as latent heat energy storage medium for effective thermal management. Presently, PCM nanocomposites have been prepared by dispersing aluminum dioxide (Al₂O₃) nanoparticles (NPs), which act as thermally conductive nanofillers, in molten magnesium nitrate hexahydrate (Mg(NO₃)₂·6H₂O), an inorganic salt hydrate. Al₂O₃ NPs with mass fractions of 0.5, 1.0 and 1.5 wt% have been dispersed in liquid PCM to obtain PCM nanocomposites, which are used to study the heat transfer properties. The morphology of the Al₂O₃ NPs, PCM and PCM nanocomposites has been studied by scanning electron microscopy (SEM). Fourier-transform infrared spectroscopy (FTIR) analysis was carried out to investigate the interaction between Al₂O₃ and PCM in PCM nanocomposite. The melting (charging) and solidification (discharging) characteristics of the PCM nanocomposites have been recorded and analyzed. The experimental results clearly showed that the rate of melting and solidification of PCM nanocomposite increases by 15% and 38%, respectively, with an increase in the mass fraction (1.5 wt%) of nanofillers as compared to the pristine PCM. The observed reduction in heat release time confirmed the effective enhancement of thermal conductivity in Al₂O₃-PCM nanocomposite samples as compared to the pristine PCM. The prepared PCM nanocomposites displayed superior heat transfer capability, making it a potential candidate for thermal energy storage.

The heating effect in solar panels under solar irradiation is a major problem. The elevated solar cell temperature causes a decrease in its efficiency. Therefore, the research community is driven towards enhancing the working efficiency of solar panel by thermal cooling techniques. In this direction, activated carbon-based cooling layer beneath solar cell has been proposed and experimental optimization has led to enhance working efficiency by reducing the working temperature of the device from 88 to 69.5 °C. This paper presents a theoretical investigation of experimentally observed temperature-dependent solar cell parameters, such as open-circuit voltage (V_oc), short-circuit current density (J_sc), fill factor (FF) and efficiency (η), of our previous study. The reverse saturation current density (J_o) is a critical diode parameter which ultimately determines the temperature-dependent performance of the solar cell. In this work, constant factor ‘C’ value of 51.43 mA-cm⁻²K⁻³ is obtained for the calculation of reverse saturation current density in the temperature range from 273 to 373 K, and accordingly, solar cell output parameters are calculated.

Poly (3, 4-ethylene dioxythiophene)-poly (styrene sulfonate) (PEDOT:PSS) is one of the most commonly explored conducting polymers for applications in numerous electronic devices. The polymer is environmentally stable and exhibits good conductivity. The evolution of carbon nanotubes (CNTs) as filler materials has contributed to the realization of CNT-polymer nanocomposites as next-generation materials. Here, we report a two-layer device based on multiwall carbon nanotubes (MWCNT) and pure PEDOT:PSS. Different devices were fabricated by varying the concentration of MWCNT to investigate the voltage generation. It was found that the voltage varied from 0.3 to 0.6 V on increasing the concentration of MWCNT from 5 to 20 wt%.

During the summer season, the most common discomfort experienced by helmet wearer is heavy sweat, which occurs due to the excess heat formation, inside the helmet. During hot weather, helmet outer surface temperature can reach up to 50–60 °C. This heat is transferred from the helmet outer surface to inner surface, which cause discomfort to the wearer. In an effort to solve this problem, a novel helmet cooling system using PCM nanocomposite was designed to provide the thermal comfort. The PCM nanocomposite is prepared by dispersing carbon nanotubes (CNTs), acting as thermally conductive nanofiller in molten eicosane, an organic PCM. The PCM-CNT nanocomposite was packed into a lightweight, flexible material, i.e., aluminum foil, which also provides a thermal conducting path for better heat transfer. This novel cooling unit was placed between the wearer head and helmet which can provide the thermal comfort to the wearer head for 2 h. The heat inside the helmet is absorbed by the PCM pouch, through the process of conduction. The stored heat in the pouch had to be discharged for its reuse. The PCM helmet cooling system is simple and had the potential to be implemented as a practical solution to provide thermal comfort to helmet wearer.

Light-induced degradation (LID) is a major concern in solar cells as it can significantly affect the long-term stability, and this issue has been highly observed in modules of silicon substrates doped with boron during the Czochralski (Cz) process. In addition to LID, major performance degradation has been observed at elevated temperature conditions in case of Cz silicon solar cells as well as mass produced multi-crystalline PERC solar cells which use dielectrically passivated surfaces. Increasing the efficiency of solar cells has proved to be a challenging task, and hence further reduction in degradation should be controlled and mitigated for better performance of cells. This review paper helps to understand several causes behind LeTID like excess carrier concentration, temperature and its effects on PERC solar cells. Few possible mitigation techniques like fast firing and laser annealing which are practiced by Tier 1 Module manufacturers are discussed at the end.

One-dimensional nanofibers fabricated by the process of electrospinning have found engaging applications in the field of dye sensitized solar cells (DSSC) due to semi-directed electron transport. Current research accounts for the development of conductive mats made from nanofibers, which is achieved through the electrospinning of TiO₂–ZnO composites and by using polyvinylpyrrolidine as a carrier solution. This fiber was annealed at 450 °C to attain a continuous network of conducting nanofibers. ZnO from the composite was selectively etched to fabricate high surface area anisotropic TiO₂ hierarchical fiber. Morphological and phase analysis conducted by scanning electron microscopy and X-ray diffraction studies confirmed the formation of anatase phase and 1-D hierarchical morphology of TiO₂. These structures were employed as photoanodes in DSSC, which had shown superior photoconversion efficiency.

Renewable energy resources are clean and nearly everlasting in nature. These days, daylighting using renewable energy resources is of great concern. The sun is an extraordinary source of renewable energy and is an immense source of illuminance available during daytime. The available daylight can be harnessed using an appropriate daylighting device to illuminate dark spaces located at a distance from conventional fenestration. Innovative daylighting systems have the capability to deliver the desired level of illuminance in deep-plan and high-rise buildings. Tubular daylighting device (TDD), one of the passive daylighting devices, is discussed in this paper. This study reviews the effect of various parameters affecting the performance of TDD. Numerical simulation was done for 300-mm diameter transparent dome collector with two configurations of mirror light tube of a vertically projected length of 830 mm. Performance of TDD has been evaluated in the summer, equinox and the winter solstices for clear sky conditions. The results were analyzed for direct and diffuse components of sunlight separately.

The deposition of CdS thin film using three different methods, that is, thermal vapor deposition, electrodeposition and chemical bath deposition for the application as electron transport layer (ETL) in perovskite solar cells has been reported. Surface morphology of thin films obtained by all three methods was analyzed using SEM images. Optical properties were studied using UV-visible spectroscopy. The film deposited by thermal vapor deposition showed high uniformity, and however, adherence properties and transmittance properties are found to be poor. Thin film fabricated by chemical bath deposition showed high uniformity with very good adherence properties but poor transmittance. Thin film obtained by electrodeposition showed good surface morphology, improved adherence properties and best transmittance properties in the visible region and was found suitable to be used as ETL.

Requirement of energy for human sustenance and growth has increased exponentially during the last century. The rate of rise in demand for energy has reached unprecedented levels leading to widening of gap between demand and supply of electric energy due to the scarcity of resources. The harmful effects of excessive usage of energy on the environment pose a great danger to the sustainability of our ecosystem. In this scenario, it becomes pertinent to design a strategy for increased efficiency of electricity utilization with an aim to minimize air pollution and carbon footprint. Hence, energy management systems are the need of the hour to identify the potential for improvements in energy efficiency. However, the implementation of Energy Information and Management System (EIMS) in academic institutes is extremely limited due to lack of awareness and relevant green policies. The current work presents a blueprint of Energy Information and Management System for an academic institute leading to multi-measure energy efficiency through multiple strategies including equipment operational improvements and upgrades, and occupant behavioural changes. The design of Intelligent EIMS enables energy savings relative to a baseline model, which predicts energy consumption from key parameters such as occupancy levels mapped with the timetable and operational schedule. The need for policies to be adopted by educational institutes for optimum utilization of electrical energy has been discussed and presented in the paper. In the present work, the different sub-domains/facilities of the college were primarily divided into three categories, namely facilities mapped with college timetable (like classrooms, laboratories, etc.), facilities mapped with fixed or regular schedule (like hostel mess, corridors, etc.) and facilities independent of college timetable or fixed schedule (like canteen, staffroom, common room, etc.). The two basic categories were further subdivided on the basis of scheduled usage and ad hoc usage of these facilities. Based on these categorizations, policies for energy usage were framed for these facilities, and prototype EIMS was designed and implemented at Maharaja Agrasen College, University of Delhi. 4.8% saving in the power consumption was observed post-EIMS implementation.

In the present study, the effects on the thermal performance of nanofluid in flat-plate solar collector are studied experimentally. The thermophysical properties (thermal conductivity, viscosity, density, and specific heat) of CeO₂–water nanofluid measured with a wide range of volume concentrations (0.25–2.0%) using 30 nm particle size. Maximum enhancement in thermal conductivity is observed up to 41.7% at 1.5% volume fraction of nanofluid at an 80 °C temperature in comparison with the base fluid. Viscosity decreases with increasing the temperature but increases with a particle volume concentration of nanofluid at a particular temperature. The experimental setup fabricated for the study of heat collection using a flat plate. The mass flow rate of nanofluids was adjusted (at a given volume concentration) for experimentation. The collector temperatures, ambient, and tap water temperatures, radiation, and wind speed were measured. Experimental results exhibit that the maximum collector efficiency is obtained up to 57.1% at an optimum concentration with a mass flow rate of 0.03 kg/s. The results show that the CeO₂–water nanofluid as working fluid improves the collector efficiency in comparison with water as a working fluid. This also has been observed that the thermal efficiency of collector increases with a decrease in the temperature reduced parameter.

In the development of next-generation solar panels, high-energy conversion efficiency has been the focal point of global research in energy. More than 80% of the efficiency of solar panels is wasted. In order to materialize this wasted energy, there has been an emerging interest in innovating hybrid solar–thermoelectric systems. In this chapter, we propose a novel hybrid photovoltaic–thermoelectric system and its expansive experimental analysis. This modified system consists of a solar wafer, thermoelectric generator (TEG), and a heat sink, which is placed beneath the solar cell of the same size to dissipate heat. A series of experiments have been performed under certain laboratory conditions, which remain constant for all sets of experiments. The heat sink beneath the solar cell reduces the working temperature of the cell from 72 °C (without heat sink) to 52 °C (with heat sink and TEG), which leads to approximately 10% increment in the relative efficiency of the solar cell. Finally, a thermoelectric generator (TEG) is inserted between the solar cell and heat sink. The TEG adds an extra power of 1.2 mW to the total output of the system.

Electrochemically active conducting polymers are an important class of materials for applications in energy storage devices. Herein, we report the synthesis of an electrically conducting polypyrrole (PPY) through ferric chloride initiated chemical oxidative polymerization of pyrrole in presence of supercritical carbon dioxide at 70 and 80 °C. The formation of PPY was ascertained through various analytical methods. Polypyrrole graphite electrodes (PGEs) were fabricated through dispersion of PPY synthesized at 70 and 80 °C into graphite in presence of sulfonated polysulfone binder and named as PGE1 and PGE2, respectively. PGE2 demonstrated better DC conductivity over that of PGE1 with morphology retention up to 35 K. Electrochemical studies reveal superior capacitive performance of PGE2 in KOH electrolyte (97.74 F/g) and reduction in corrosion rate of steel electrode @0.16 mm/y.

Recent studies on the potential of the nanofluids on the performance enhancement of the parabolic trough collectors seem to be pointing toward development of the next generation of the solar collectors having great potential to be used for co-generation with integrated solar thermal systems. To achieve it, most researchers are investigating the superior performance of non-conventional heat transfer fluids, such as the nanofluids. The present paper is an effort to review recent research efforts on the performance of parabolic trough collectors using nanofluids. Studies on the various properties of nanofluids seem to be suggesting the positive impact of these fluids in increasing the heat transfer characteristics. The concurrent studies carried out to use nanofluids in coupled solar thermal systems are likely to enhance the process of heat energy collection from the sun in a highly concentrating trough type collector. The objective of the current study is to report recent progress on thermal efficiency enhancement in the parabolic solar trough collector using nanofluids. Experimental and numerical simulation results have been covered by referring to recent research papers. This work will act as a valuable tool to future researchers.

Under swift heavy ion irradiation at different fluences, the structural transformations of fullerene C₇₀ thin film prepared by thermal evaporation are investigated. Fullerene C₇₀ thin films are irradiated with 65 MeV Ni ions beam at different fluences from 1 × 10¹² to 1 × 10¹⁴ ions/cm². The impact of energetic ions on the fullerene molecule leads to the extinction of C₇₀ molecule. In order to study the stability of fullerene C₇₀ under ion irradiation, damage cross section and ion track radius of damaged cylindrical zones are determined using fullerene C₇₀ vibration modes and their change at different fluences as recorded by Raman spectroscopy. Damage cross section is found to be 1.01 × 10⁻¹³ cm², and ion track radius of damaged cylindrical zone is found to 1.8 nm. Fullerene C₇₀ is completely converted from crystalline structure to amorphous carbon at a fluence of 1 × 10¹⁴ ions/cm².

The energy generating modular array network is the costliest unit of solar photovoltaic systems. The amount of energy that is transformed into electricity by the solar photovoltaic panels depends on its tilt angle with the horizontal plane as well as the orientation of the module. The optimum tilt angle of these panels is decided on the basis of annual solar energy incident on the panels, and this angle is kept fixed during the year-round cycle. In this paper, we have investigated the optimum tilt angles determined on the basis of the amount of energy incident on the panels at yearly and seasonal basis. In this investigation, we have also investigated the shading effect of these panels on the rooftop at Delhi (latitude 28.7° N). In accordance with the latitude of Delhi, the solar radiation data has been classified into three seasons, i.e., summer (May, June, July, August), winter (November, December, January, February) and equinoxes (March, April, September, October). It is found that the panels placed facing due south and seasonally adjusted at their optimum tilt angles will produce more electrical energy, 6.52% in summer, 5.94% in winter and 5–7% more electrical energy on annual basis and a larger shadow in summer and smaller shadow in winter in comparison with the panels at annually fixed tilt angle, and this in turn will decrease the indoor solar heat flux in summer and enhance the indoor solar heat flux in winter and hence will favorably affect the indoor solar heat flux as well as load leveling.

Solar energy is an alternative to conventional resources of energy. Among the many applications, solar parabolic trough collector is an application that receives heat from the radiation of the sun. Such energy is an alternative way for many rural applications: solar cooker, water pumping, water heating, solar driers, etc. Parabolic trough collector consists of the collector of a paraboloid shape and mounted with the mirrors to reflect and concentrate the solar radiation and focus the same over the receiver/absorber. This heat energy is absorbed by the heat transfer fluid inside the receiver. Such energy also converts water into steam and usually used to drive conventional electrical generators. Receiver heat loss by the mode of convection and radiation is the major cause of lower thermal efficiency. This is why it is essential to study the methods for enhancement of the heat transfer in the parabolic trough receiver. This study focused on the review and feasibility of various heat transfer augmentation techniques for parabolic trough collector receiver/absorber. Study from various publications considers various techniques that are being used by many researchers; this includes use of evacuated receivers, inserts, porous disk, fins, nanofluids, various types of inserts, etc. It is observed that with the use of insert heat transfer augmentation was reported as the highest; however, few of the insert types are yet not used.

Zinc oxide (ZnO) nanostructures have been successfully synthesized using rapid thermal chemical vapor deposition (RTCVD) technique under ambient oxygen environment. During the growth of ZnO nanostructure, the gas pressure of oxygen was maintained at 5 Torr, and the low pressure inside the growth chamber was kept of the order of 10⁻⁶ Torr in order to increase the vapor pressure during sublimation. The morphological and application aspects of the grown ZnO nanostructures were studied at room temperature and at LN₂ temperature. Different characterization techniques such as X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDAX) and UV–Vis spectroscopy have been performed for elemental analysis, crystalline nature, shape, size and band gap calculation of as-grown ZnO nanostructure. The results exhibited that grown ZnO nanostructures have various applications including solar cells and supercapacitor for energy storage devices.

There are various complexities involves with enzymatic glucose sensors such as poor shelf life due to the inherent instability of an enzyme, a fabrication complexity included in enzyme immobilization procedures and interference caused by soluble redox mediators. Therefore, research towards enzymeless glucose sensing has increased. Further, the integration of photovoltaic or alternate energy harvesting methods with glucose sensors results in the development of cost-effective and energy-efficient biosensor systems. Continuous technological advancements of novel materials having distinctive nanostructures assist in understanding the fundamentals of enzymeless glucose detection. In this paper, we have discussed the electrochemical method of glucose detection and the role of nanostructures in development of energy-efficient electrochemical non-enzymatic glucose sensors.