Performance assessment of compound parabolic concentrating photovoltaic system based on optical-thermal-electrical-environmental coupling

Abstract

Based on established optical-thermal-electrical-environmental coupling model and proposed method for calculating electrical efficiency, the effects of tilt angle (θ) on the optical performance, thermal performance and electrical performance of compound parabolic concentrating photovoltaic (CPC-PV) system were numerically investigated by using the coupled Monte Carlo ray tracing (MCRT) and finite volume method (FVM). The results show that with the increase of θ, the peak irradiation flux on the PV panel surface increases sharply. When θ is larger than the critical angle, the shadow area appears and the distribution uniformity of irradiation flux decreases rapidly. Under natural convection condition, increasing θ reduces the distribution uniformity of temperature on the silicon elements with a maximum temperature difference of 120.93 °C at the same position. While, the air average flow velocity around PV panel and reflector surfaces decreases, and the maximum flow velocity appears on reflector surface. Radiative heat loss is dominant in CPC-PV system, and convective heat transfer on the glass surface has a greater impact on the combined heat transfer than that on the TPT surface. From the aspects of values and variation trends, the electrical efficiency calculated by using traditional empirical formula defies the facts. The regional discrete integral method proposed in this study accounts for the effects of shaded areas and non-uniform temperatures on electrical performance. The maximum difference between the electrical efficiency calculated by using the present method and the traditional empirical formula is 10.59 %.