An Experimental Investigation on the Effect of Al2O3-H2O and Cuo- H2O Nanofluid on the Efficiency of Flat-plate Solar Collectors

iIn this research, the effect of using aluminum oxide and copper oxide nanofluid (pure water mixed with Cuo and Al2O3 nanoparticle with 35-50 nm diameters) on the thermal efficiency enhancement of a heat pipe on the different operating state was investigated. The heat pipe was made of a straight copper tube with an outer diameter of 12mm and inner diameter 10mm. In the heat pipe tube, there is a 90 curve between the evaporator and condenser sections. The tested concentration levels of nanofluid are 0.3 %, 0.6 % and 0.9 %wt. Results show that by charging the nanofluid to the heat pipe, thermal performance is enhanced by reducing the thermal resistance and wall temperature difference. The thermal efficiency of heat pipe charged with nanofluid is compared in water, Al2o3 and Cuo.