The effect of temperature distribution on parabolic triangular-based CPVT system performances: Electrical and thermal perspectives

Abstract

The performance of photovoltaic (PV) and photovoltaic-thermal (PVT) systems is affected by environmental parameters and working conditions such as, partial shading, refrigerant and operating temperature. This study focuses on the investigation of the operating conditions and performance of a low concentrated parabolic-trough PVT (CPVT) system. Electro-thermal (electrical and thermal) analysis of the CPVT system was investigated. In the electrical analysis, the effect of series, serial-parallel (SP), total cross-tied (TCT) and grouped connection forms were investigated using a single diode model. In thermal analyses, temperature distribution of the CPVT system was investigated using finite volume methods considering different fluid inlet temperatures. Firstly, thermal analysis was carried out under certain conditions of the CPVT system. Then the obtained temperature distribution was applied to the electrical model. Thus, the electrical and thermal performance of the CPVT system under certain conditions was estimated. Obtained results show that series connection is negligibly better than TCT connections. According to identical mass and pressure and under operating conditions, fluid inlet and outlet temperature differences is 8.77 °C for water. PV module temperature increases up to 110 °C, when fluid inlet temperature is 50 °C for R134a. So, the PV module output power significantly decreases. When the electrical and thermal efficiencies of the CPVT system were evaluated, water obtains better results than the other fluids due to its high specific heat. Therefore, fluid, fluid mass and pressure have to be carefully selected and designed before system's experimental design. Finally, fluid mass should be selected at more and more rates in high temperature applications.