Effect of the use of metal–oxide and boron-based nanoparticles on the performance in a photovoltaic thermal module (PV/T): Experimental study

• Different nanofluids is used in PV/T module for cooling • The best thermal efficiency is obtained as 37.91% in ZnO (0.03). • The highest sustainability index is determined 1.207 in ZnO (0.03) • The exergy efficiency is higher 3.8% in ZnO (0.03) compared water-antifreeze. • The electrical efficiency is obtained 15.01% in ZnO. Renewable energy sources are constantly on the agenda because the fossil fuels used are limited and the need for energy is constantly increasing. Among these resources, solar energy stands out because it is clean and endless energy. Nowadays, heat energy and electrical energy production from solar energy are quite common. Photovoltaic (PV) solar panels can convert a limited portion of the solar energy falling on them into electrical energy. In PV panels, heat energy that cannot be converted into electricity is discharged back to the external environment. Photovoltaic thermal (PV/T) panels are used to remove this heat from the system and convert it into useful energy. Many cooling techniques are applied to reduce the surface temperature of PV/T panels and increase their electrical efficiency. One of these techniques is liquid-cooled PV/T panels. In some of the studies, forced circulation (using a pump) and in others natural circulation (thermosiphon effect) were applied. In this study, a natural circulation indirect heated PV/T system was designed. Al 2 O 3 , ZnO, and BN nanoparticle concentrations were added to the cooling water to increase heat transfer within the PV/T panel. According to the experimental results, using nanofluid in the PV/T panel increased the thermal and total efficiency. Total efficiencies of ZnO, BN, and Al 2 O 3 were obtained as 52.8%, 47.86%, and 43.49%, respectively, at 0.03 concentration. The highest exergy efficiency and sustainability index were determined as 17.155% and 1.207, respectively, at 0.03 concentration of ZnO nanofluid.