EFFECTS OF A MIXTURE OF CuO AND Al2O3 NANOPARTICLES ON THE THERMAL EFFICIENCY OF A FLAT PLATE SOLAR COLLECTOR AT DIFFERENT MASS FLOW RATES

Abstract

This research experimentally investigates the effects of adding nanoparticles with a volume fraction of 0.1% on the thermal efficiency of a flat plate solar collector at different mass flow rates. CuO/water and Al2O3/water nanofluids were studied in mixtures with different mass ratios. The results show that the nanofluids increase the efficiency of the solar collector significantly. The best mass flow rate was obtained for each nanofluid to obtain the maximum collector efficiency. Compared with water, the solar collector efficiency at the optimal rate is increased by 50%, 16%, 15%, 8%, and 2% for CuO, Al2O3, 25% CuO + 75% Al2O3, 75% CuO + 25% Al2O3, and 50% CuO + 50% Al2O3, respectively. Because of the high thermal conductivity of the CuO nanoparticles, the energy received from the collector increases. The highest energy absorption occurs in the case of CuO nanoparticles, followed by Al2O3 nanoparticles. Although the Brownian motion of Al2O3particles can be a significant feature in the heat transfer properties, the high thermal conductivity of CuO had a greater effect. Finally, the heat loss and heat absorption through the solar collector were calculated for all of the nanofluids to confirm the results.