A solar photovoltaic (PV) system produces electrical energy from solar energy. This green, sustainable system has low energy conversion efficiency due to the rise in PV temperature throughout the day. In order to keep the temperature of the panels close to ambient, this study examines the usage of hydrated salt (HS36) as a Phase Change Material (PCM) for PV cooling. The primary goal of this experimental study is to cool the PV panel by introducing PCM behind the PV system (PV-PCM), thus increasing its performance. An energy and exergy performance assessment was carried out on PV and PV-PCM systems. The result indicates that placing a PCM over the back of the solar panel’s back reduced the operational temperature by 25.4% and increased the panel’s electrical efficiency by 17.5%. PV-PCM systems’ maximum exergy efficiency increased by 12.57%, and their exergy destruction ratio decreased by 12.49%. The proposed PV-PCM system with HS36 PCM increased the PV panel performance and can be deployed in the PV system.

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.

By modifying the angle of tilt of 2 distinct tool pin shapes, both tapered with and without threaded structures, TPT tool pin with threads and TPNT tool pin with no threads, the mechanical behaviour and microstructural attributes were examined for the joints of AZ91B alloy formed by friction stir welding. Spindle torque and unique forces operating laterally and axially (referred to as Y-force and X-force, respectively) were created at the junction of the tool and plate, which were monitored and assessed in order to know the influence of degrees of tilt. When the tools angle of tilt advances, torque and forces of the spindle also show an increasing trend that is important to friction stir welding. The spindle torque and Y-force produced by the TPT tool are higher than those of the TPNT tool, whereas the X-force associated with the TPT tool is less. Discrepancies in forces grow along the concurrent increase in the angle of tilt for the TPNT as well as TPT tools, exhibiting opposite behaviour. The onion ring-type structure was visualized in the threaded tool pin structure TPT due to the high flow of plasticized metal compared to TPNT tool joints, for which the onion ring shape is not visible. With the TPT tool, the joint made at a 0° angle of tilt had a peak tensile strength of 232MPa.