LAUSR

In this research, the effects of sonication time and volume concentration of cupric oxide (CuO)/water nanofluids on the thermal conductivity, viscosity and performance of photovoltaic–thermal (PVT) solar collector are investigated experimentally. Pure water, 0.05, 0.1 and 0.2% volume concentrations of CuO/water nanofluids prepared with 1, 2, 3 and 4 h sonication time are used as the heat transfer fluids in this study. The experimental results show that the thermal conductivity and viscosity of nanofluids are the functions of sonication time and volume concentration and using a 0.2 vol.% nanofluid prepared with 4 h sonication time, the thermal conductivity and viscosity were enhanced up to 3.5 and 7.5%, respectively, with respect to the base fluid, whereas for the same volume concentration and sonication time, the observed thermal and electrical efficiencies of the PVT solar collector are 80.7 and 15.1%, respectively, at 12 noon. It was observed that the highest total efficiency of the PVT solar collector of about 95.8% was obtained for 0.2% CuO/water nanofluid and 4 h sonication time at 12 noon.