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Hybrid photovoltaic-thermal heat pump (PV/T-HP) solar energy systems are promising since they can achieve a system total efficiency greater than 80%. By maximizing the output of a PV/T system for simultaneous heating and cooling, this strategy can meet over 60% of urban households’ heating needs and around 40% of their cooling needs. In this work, a novel PV/T evaporator was designed, fabricated, and an aluminium foil encapsulated hydrated salt (HS36) PCM was integrated with the PV/T evaporator of the PV/T direct expansion heat pump system (PV/T-DXHP). Energy analysis was carried out on the PV/T-DXHP system with PCM in tropical climate regions of India for achieving net zero energy buildings. The experimental study revealed that the average PV electricity efficiency was 14.17%, which is near the PV panel’s STC value. The average thermal efficiency of the system was 104.38%, and the PV/T system’s average overall efficiency was 117.58%. The heating and cooling COPs of the system were 5.73 and 4.62, respectively. It was concluded that net-zero energy buildings are possible with the help of photovoltaic heat pump systems that use PCM and solar energy to make electricity, cool spaces, and heat water.

The design of solar concentrating collectors for the effective utilization of solar energy is a challenging condition due to tracking errors leading to different divergences of the solar incidence angle. To enhance the optical performance of solar parabolic trough collectors (SPTC) under a diverged solar incidence angle, an additional compound parabolic concentrator (CPC) is introduced as a secondary reflector. SPTC with CPC is designed and modeled for a single axis-tracking concentrating collector based on the local ambient conditions. In this work, the optical performance of the novel SPTC system with and without a secondary reflector is investigated using MATLAB and TRACEPRO software simulations for various tracking errors. The significance parameters such as the solar incidence angle, aperture length, receiver tube diameter, rim angle, concentration ratio, solar radiation, and absorbed flux are analyzed. The simulation results show that the rate of the absorbed flux on the receiver tube is significantly improved by providing the secondary reflector, which enhances the optical efficiency of the collector. It is found that the optical efficiency of the SPTC with a secondary reflector is 20% higher than the conventional collector system for a solar incidence angle of 2°. This work can effectively direct the choice of optimal secondary reflectors for SPTC under different design and operating conditions.

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The moisture present in the farming yields and in seeds is one of the greatest affecting factors which are playing a major role in storing it for longer days. The quality of products can be increased by preventing the formation of bacteria, yeast, etc. The moisture content present in the groundnut must be between 10 to 15% (weight basis). In this study a numerical analysis was investigated on a solar dryer, which is used to diminish the moisture content present in the groundnut to preserve it for longer days. The performance analyses of forced convection solar dryer with dryer compartment were analysed based on local ambient conditions at sathyamangalam for various required design and operating parameters such as moisture removal rate, air mass flow rate, air inlet, and outlet temperature. The proposed basic solar collector aperture area is about 2 m2 which is made of the copper plate as an absorber plate coated with black powder coating for better absorption. The moisture content present in the freshly harvested groundnut varies from 25-30 % (weight basis). The analysis was done for drying groundnut to remove the moisture content to the required moisture level of 10% by utilizing solar energy. The results from the study illustrate that the Efficiency of dryer is a maximum of 39.2% for the optimized mass flow rate of 0.022 kg/s and also it was found that the dryer overall efficiency and average collector temperature is gradually decreasing for increasing the mass flow rate.

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Increase in demand for drinking water due to growth in world population and industrialization has lead route for innovating new technologies for purifying sea water. Desalination by conventional energy source increases the emission of greenhouse gases and leads to global warming. As a solution for pollution and water scarcity, solar desalination techniques are incorporated worldwide for converting brackish water into portable water using solar power. Solar power helps water purification via solar thermal systems and also using solar photovoltaic panels which provide electric supply. This review article consolidate the solar thermal energy based small, medium and large scale solar desalination plants for extracting pure water. The environmental benefits and the futuristic challenges of utilizing solar thermal system for purification of water is also highlighted.