Experimental study on the performance of different photovoltaic thermal collectors with nano-technology

Abstract

ABSTRACT The process of cooling the photovoltaic cell effectively leads to improving the electrical efficiency of the cell. Herein, the current experimental study employed three different nanofluids (CuO, ZnO, and TiO2) to cool the PV panel to produce a hybrid collector, also known as a photovoltaic thermal solar collector (PVT). The nanoparticle volume fraction was 0.1, 0.2, and 0.3 vol%. The process of cooling the PV panel was carried out using a copper tube on the back of the PV, which was placed to cover the largest possible area on the back of the PV. Three different flow cross sections – rectangular, square, and circular – were used to compare them. This experimental study was carried out under solar radiation conditions ranging from 450 W/m2 to 750 W/m2, and the flow rates of the nanofluid were 0.5, 1, 1.5, and 2 L/min. The results show the electrical and thermal efficiency of the PVT system at different conditions. The electrical efficiency increased as a result of adding nanofluid compared to normal water, where the cell with CuO/nanofluids gave the highest value of electrical efficiency at 450 W/m2, equaling 11.8%, while it was equal to 11.6%, 11.5%, and 10.8% for ZnO/nanofluids, TiO2/nanofluids, and water, respectively. An increase in mass flow rate leads to increased thermal, electrical, and combined PVT efficiencies. As well. The high mass flow rate increases the heat transfer coefficients between the tube wall and flowing fluid, which in turn decreases the PV module’s temperature. Finally, the rectangular section and the CuO/nanofluids gave the best value for the electrical power, which reached 83.17 W, and the highest electrical efficiency, which reached 11.5%.