Multi-objective optimization of a photovoltaic thermal system with different water based nanofluids using Taguchi approach

Abstract

In this study, the effect of different nanofluids on the electrical and thermal efficiencies of photovoltaic thermal (PVT) systems was investigated experimentally and the variables affecting the efficiency were optimized by the Taguchi method. Experiments were carried out under laboratory conditions on the PVT system presently developed. In this study, a novel partitioned cooler block in the form of a rectangular prism was designed and used. Thus, the contact between the cooler block and the back surface of the PV panel and the associated PVT efficiency were increased. The following physical characteristics have been identified as the independent variables for the experiments carried out: SiO2/Water, Al2O3/Water and CuO/Water as different types of nanofluid, 0.1, 0.2 and 0.3 as volumetric concentration, 0.55, 1.1 and 1.65 lpm as volumetric flow rate and 300, 600 and 900 W/m2 as irradiance level. The reliability of the measurements made during the experiments was ascertained through the uncertainty analysis performed. The maximum electrical efficiencies of the PVT system for SiO2/Water, Al2O3/Water, and CuO/Water nanofluids were found to be 20.69 %, 21.18 %, and 20.77 %, and the maximum thermal efficiencies to be 57.06 %, 63.01 %, and 66.49 %, respectively. As the optimization method for determining the most optimum combination of variables, Taguchi analysis has been employed. As a result of this analysis, it has been shown that the most effective variables on the electrical efficiency of the PVT system are the irradiance, flow rate, volumetric concentration, and nanofluid type, respectively. On the other hand, regarding the thermal efficiency of the PVT system, the most effective variables are the irradiance, flow rate, nanofluid type, and volumetric concentration, respectively.