Dynamic coupling of a heat transfer model and whole building simulation for a novel cadmium telluride-based vacuum photovoltaic glazing

Abstract

In recent years, building-integrated photovoltaic (BIPV) windows have drawn attention from both the building industry and academic society. As a multifunctional application of photovoltaic technologies, semi-transparent BIPV panels can generate renewable energy in situ and play the role of typical windows. Unlike those PV windows made by crystalline silicon solar cells, the semi-transparent cadmium telluride (CdTe) photovoltaic (STPV) windows can admit natural daylight with a certain degree of transmittance without any shading. Therefore, it can provide better visual comfort to occupants. However, typical BIPV windows are not suitable for cold regions due to inadequate thermal insulation. To improve the thermal performance of the BIPV glazing, a novel CdTe-based vacuum PV glazing (VPV) is developed with a highly integrated three-layer structure. To fully understand the dynamic heat transfer process and thermal behaviour, this study developed a mathematical heat transfer model for the CdTe-based VPV. The dynamic heat transfer model was validated with laboratory tests. To investigate the whole year performance of the VPV, a dynamic coupling approach is proposed to integrate the transit heat transfer model with a whole building simulation model conducted by EnergyPlus to obtain more accurate simulation results. Comparing the simulation results of the decoupled and coupled methods, it was found that EnergyPlus tends to slightly underestimate the cooling energy consumption and overestimate the heating energy consumption to a considerable level. Therefore, the dynamic coupling approach is more reliable than the EnergyPlus model, especially in the heating-dominated regions.