A novel spectrally selective radiation shield for cooling a photovoltaic module

Abstract

The cooling of photovoltaic panels plays an important role in improving electrical efficiency and increasing the lifetime. In this paper, a radiation shield for filtering the thermal part of solar irradiance has been proposed as a passive cooling method. A 3D model of a PV module with all consisting layers has been numerically simulated. The radiative transfer equation has been solved by discrete ordinates (DO) method. The numerical results of the uncooled PV module have been compared with the experimental data. The radiation shields with 40% and 80% reflections in the wavelength interval between 1 μm and 2.4 μm have been performed to reduce the thermal effect of solar irradiation over the PV module. The effects of radiation shield on the instantaneous and monthly average surface temperature of the PV module have been investigated. It has been found that the effect of radiation shield on temperature reduction of the PV module is more considerable in seasons with high solar irradiation. The numerical results show that the radiation shield with 80% reflectivity has more effect on temperature reduction and the electrical efficiency of the PV module. The numerical results reveal that, for solar irradiation between 1025 and 1142 W/m2, the radiation shield with 80% reflection can increase the electrical efficiency by about 5.14%–5.72%.