Electric and Thermal Performance Evaluation of a Serpentine-Pipe PVT Solar Collector

The promotion and application of a solar photovoltaic thermal (PVT) collector is increasingly favored. In this paper, a solar PVT collector with a serpentine pipe has been investigated by using the double iteration strategy. The simulation results are in good agreement with the experimental data. The effects of ambient temperature, solar irradiance, distance between pipes, pipe diameter and mass flow rate on the thermal efficiency and photoelectric conversion efficiency (PCE) are discussed. Specifically, the results show that with an increase in the ambient temperature, the thermal efficiency of the collectors increases and the PCE decreases. By contrast, as the inlet water temperature decreases, the heat dissipation capacity is enhanced, which in turn both improves its thermal efficiency and PCE. Furthermore, the reduction in the distance between pipes also helps to improve thermal efficiency. However, when the distance between pipes is reduced to 0.1 m, the reduction in the thermal efficiency is not significant. It is worth noting that there exists an optimal solution to the influence of the pipe diameter on the thermal performance of the collector. This implies that the large pipe diameter will reduce the thermal efficiency to some extent. In addition, as the mass flow rate increases, the thermal efficiency is improved, and the plate temperature and outlet water temperature decrease simultaneously, with a greater decrease in outlet water temperature.