Performance enhancement of a hybrid photovoltaic/thermal system using wire coils inside the cooling tube: numerical and experimental case

There are several strict reasons to overcome the dependence on fossil fuels and count on renewable energy sources such as solar energy. In this study, a numerical/experimental investigation on a hybrid photovoltaic/thermal system is carried out. A hybrid system would achieve higher electrical efficiency by reducing panel surface temperature, and the heat transferred could have further benefits. Using wire coils inside cooling tubes is a passive method selected in this paper to improve heat transfer. The appropriate number of wire coils was determined using numerical simulation, and then the experimental study began in real-time. Different flow rates with different pitch to diameter ratios for wire coils were considered. The results show that placing three wire coils inside the cooling tube would increase the average electrical and thermal efficiency by 2.29 and 16.87%, respectively, compared to the simple cooling mode. According to the results, if a wire coil is used in the cooling tube, a 9.42% increase in the average total efficiency based on electricity generation during a test day would appear compared to the simple cooling. A numerical method was applied again to evaluate the results of experimental tests as well as observe the phenomena in the cooling fluid path.