Numerical evaluation and sensitivity analysis on dynamic heat transfer of a novel CdTe-base vacuum PV glazing

Abstract

Building-integrated photovoltaic (BIPV) technology plays an important role on the path to carbon neutral society. The CdTe-based vacuum PV glazing is proposed to improve the thermal performance of the PV glazing. Therefore, the goals of renewable energy production and energy-efficient building can be achieved at the same time. To fully understand the dynamic heat transfer process and thermal behaviour, this study conducted a comprehensive numerical evaluation based on a mathematic heat transfer model for the CdTe-based vacuum PV glazing. It was found the average dynamic solar heat gain coefficient (SHGC) of the CdTe-based vacuum PV glazing is 0.147 and will increase with the increment of incident solar radiation. The dynamic overall heat transfer coefficient (U-value) varies from 0.451 to 0.467 W/m 2 K under summer conditions which are higher than which under winter conditions. The solar radiation dominates the total heat transfer compared with the temperature difference in the daytime. The solar radiation and ambient temperature have a negative effect on the PV efficiency and a distinctly positive effect on the outside surface temperature. However, the inside surface temperature is much more stable. A sensitivity analysis was also conducted to investigate the thermal response of the vacuum PV glazing with different design parameters and various environmental conditions. The emissivity of low-e coating is the most effective design parameter. The results indicate that the vacuum PV glazing can perform an excellent thermal insulation performance and contribute to the optimization of the design parameters in future studies.