Experimental and numerical investigations on performance of evacuated tube solar collectors with parabolic concentrator, applying synthesized Cu₂O/distilled water nanofluid

In this study, in order to enhance the thermal efficiency of the solar water heating system, the effect of reflector, parabolic concentrator, and the nanofluid copper oxide/distilled water (Cu2O/DW) for 0.01 to 0.08 volume fractions on thermal performance of an evacuated tube solar collector (ETSC) has been both numerically and experimentally investigated. The numerical analysis has been undertaken to develop the experimental setup. The TESCs were simulated for different diameters of the evacuated tube to show how diameter of the tube affects the circulation rate, and the temperature distribution inside the ETSC. To summarize the experimental results the results have been shown for pure water, 0.04 volume concentration, and 0.08 volume fraction of the nanofluid. By use of 0.08 volume fraction of the nanofluid the energy and exergy efficiency of the system were enhanced 10% and 12.7%, respectively. Moreover, the mean temperature of the tank increased dramatically by use of nanofluid. In addition, the impact of different volume concentrations on the thermo-physical properties of the working fluid, such as density, heat capacity, viscosity, and conductivity was theoretically conducted.