Experimental investigation of the effect of thermal efficiency by using nanofluid in solar collectors

Solar energy, which occupies the first place amongst the renewable energy resources, enables a more efficient energy consumption through various applications due to its ecologist nature and cheaper operating costs with the application. In the present work the effect of nanofluid, as working fluid, on the efficiency of a flat-plate solar collector was investigated experimentally. Nanofluids were prepared adding Al2O3, CuO and TiO2 nanoparticles in volume fraction 0.2%, 0.4% and 0.8%, into pure water and thermophysical properties of prepared nanofluids( thermal conductivity, viscosity..) was determined. Temperature of collector input, collector output, ambient and water, radiation, velocity and humidity were measured and recorded to compare the thermal efficiency. The mass flow rate of nanofluids varied from 50 to 250 Lit/h. The ASHRAE standard was used to calculate the efficiency. The results show that, in comparison with water as absorption medium using the nanofluids as working fluid increase the efficiency.