Experimental and numerical analysis of naturally ventilated PV-DSF in a humid subtropical climate

Photovoltaic double-skin façades (PV-DSFs) have great potential to simultaneously achieve power generation, thermal insulation and natural lighting when applied in buildings. Among them, crystalline silicon PV-DSF is one of the common types due to its high efficiency and mature technology. However, the alternate arrangement of opaque crystalline silicon and transparent glass in crystalline silicon PV-DSF complicates its heat transfer characteristics. Furthermore, the ventilation air cavity in crystalline silicon PV-DSF could induce a vertical convective heat transfer process. It is difficult to accurately predict the complex multidimensional heat transfer process in crystalline silicon PV-DSF by simplified 1-D or 2-D thermal models. Therefore, a comprehensive numerical model of PV-DSF including the optics, electricity and 3-D heat transfer sub-models is developed in this paper to estimate the annual electrical and thermal properties of PV-DSF in a humid subtropical climate. The effects of structure, orientation, air cavity depth and solar cell coverage on the overall performance of PV-DSF are analyzed. In comparison with single-glazed semi-transparent photovoltaic, PV-DSF provides a 30.4% reduction in heat gain and a 50.3% reduction in heat loss. The preferred installation orientation is due south for PV-DSF in a humid subtropical climate. • A 3-D numerical heat transfer model of PV-DSF is established and validated. • The preferred installation orientation is due south for PV-DSF in a humid subtropical climate. • PV-DSF obviously reduces heat gain and loss compared to STPV glazing. • The difference in annual heat gain or loss of PV-DSF caused by different depths is tiny.