Thermal and electrical performance analysis of monofacial double-glass photovoltaic module with radiative cooling coating on the rear surface

Abstract

The monofacial double-glass photovoltaic modules are still seriously affected by the temperature effect. The coatings with spectral regulation characteristics are expected to reduce the impact from the temperature effect. A coupled thermal-electrical model was established to evaluate the thermal and electrical performance of the monofacial double-glass modules applied with different spectral regulation coatings, including sub-bandgap reflection coating, mid-infrared emission coating and a combination of the two coatings. The cooling effect and output power gain of these coatings on the front and rear surface of the modules were compared comprehensively. The results show that the most suitable cooling coating for the module is the mid-infrared emission coating (i.e. radiative coating) on the rear surface when absorption loss of solar cell caused by spectral regulation coating was considered. Thus, we prepared the radiative coatings of TPX/SiO2 by doping SiO2 particles into the TPX polymer matrix. The thermal and electrical performances of the modules applied with different coatings on the rear surfaces of PV modules were calculated to optimize the coating parameters, such as thickness, size and volume fractions of SiO2 particles. The results reveal that the module applied with the TPX/SiO2 coating (size: 50 nm, volume fraction: 5 vol%, thickness: 60 μm) on the rear surface exhibited the lowest temperature and the highest output power. In the outdoor experiments, the radiative coating realized the cooling effect of ∼1 °C, and the efficiency improvement of 0.21 %. This work demonstrates that radiative cooling coating on the rear surface can bring PV module heat dissipation. Further research and development of radiative coatings would improve the cooling and electrical performances of PV module.