A comparative study on energy performance between different PV/T systems and PV system in a cold highland area in winter

This paper aims to investigate the influence of active cooling and natural cooling on the electrical performance of photovoltaic (PV) modules in a cold highland area in winter, and the thermal performance of two photovoltaic thermal (PV/T) systems for space heating. A comparative system with exactly the same size of a PV system, liquid-cooled PV/T system, and heat pipe PV/T system was designed and constructed in Ganzi city, China. The energy performance of these systems was tested under real weather conditions for several days. The experimental results show that the PV module can achieve the cooling effect by natural cooling, with a daily average temperature between 30 °C and 40 °C, and an electrical efficiency 3.71% higher than that of active cooling. However, the temperature of naturally cooled PV modules fluctuates drastically with time, and the temperature changes above 10 °C in a short time. The solar energy conversion efficiency of PV/T systems is more than 2.67 times that of a PV system. The heating power of the liquid-cooled PV/T system and heat pipe PV/T system can reach 847.4 and 948.5 W, and the primary-energy saving efficiency can reach 68.8% and 76.7%. A comparison of the intercept efficiency shows that the heat pipe PV/T system has the best energy performance.