Experimental and theoretical analysis of glazed tube-and-sheet photovoltaic/thermal system with earth water heat exchanger cooling

In the present paper, an attempt has been made to investigate the theoretical and practical performances of the photovoltaic/thermal (PV/T) system coupled with earth water heat exchanger (EWHE) cooling system for the conditions of semi-arid region of Pilani, Rajasthan. The experimental studies have been performed for different flow rates of cooling water (0.033 kg/s, 0.025 kg/s and 0.017 kg/s) for a typical day climatic conditions. An electrical efficiency comparison was made for two scenarios when the PV panel was connected or disconnected with the thermal collector and found out that the average electrical efficiency of PV/T panels is higher than the normal PV efficiency. The results of the experimental study showed that the maximum PV panel temperature goes up to 73 °C without any cooling. On the other hand, the PV panel temperature drops in the range of 43.68-49.64 °C with the flow rate of 0.033 kg/s. It has been estimated that the electrical and thermal efficiencies of the PV/T system with cooling are in the range of 8.26-8.52% and 44.06-55.45% respectively for flow rate of 0.033 kg/s. The EWHE pipe length of 38 m found to be sufficient for the proposed system. The experimental results are validated with the theoretical model by using basic energy balance equations and found in good agreement with percentage error of 0.91-12.09%.