Thermal and electrical performance assessment of a bifacial photovoltaic green facade based on CFD simulation

The bifacial photovoltaic green facade (BPVGF) system was introduced to maximize the energy and environmental advantages offered by photovoltaic buildings and vertical greening technologies, thereby contributing to the realization of the zero-carbon target in the construction sector. This system involves the vertical installation of bifacial photovoltaic panels on building facades, which are overlaid with climbing vegetation or modular plant systems. Solar radiation incident upon these facades is partially harnessed as electricity by the bifacial photovoltaic panels, while the remainder is absorbed by the plants, beneficial for summer thermal insulation. Meanwhile, the plants aid in cooling the photovoltaic materials through evapotranspiration, thereby enhancing the solar-to-electricity conversion efficiency. In this study, a computational fluid dynamics (CFD) model of the BPVGF was developed to evaluate its thermal performance. The findings indicate that the incorporation of vertical greening with varying parameters can significantly mitigate the temperatures of both the interior and exterior walls, as well as the bifacial PV panels. Specifically, with a greening thickness of 80 mm, the maximum temperature reductions for the interior and exterior wall surfaces, and the bifacial PV panels were recorded at 2.59 ℃, 5.29 ℃, and 4.72 ℃, respectively. Moreover, the photovoltaic efficiency of the bifacial PV panels experienced an increase of 2.5%. This study highlights the dual potential of vertical greening in optimizing thermal environments and elevating PV conversion efficiency.