Quantifying the benefits of BIPV windows in urban environment under climate change: A comparison of three Chinese cities

Building-integrated photovoltaic (BIPV) windows are an effective way to increase distributed PV capacity in the urban environment. However, the effects of BIPV windows on an annual scale have not been rigorously studied. In this study, we compared their performances with different window-to-wall ratios, canyon aspect ratios, and orientations in three Chinese cities. Our results show that in Beijing, BIPV windows with the southward orientation have the highest potential for power generation of 44.7 kWh/(m(2)yr), which is 1.5 times the potential in Shenzhen and Nanjing. Compared to clear windows, BIPV windows are advantageous when the window coverage is greater than 50 % in a shallow canyon. The highest electricity saving ratios are found in Beijing (29.7 %), followed by Shenzhen (26.3 %) and Nanjing (23.3 %). However, the electricity saving ratio decreases by over 10 % in deep canyons. Under future climate forcing, the saving potential of BIPV windows increases slightly in Nanjing and remain stable in Shenzhen and Beijing. The study also found that BIPV windows could increase canyon air temperatures by over 0.2 degrees C during winter days but slightly cool the canyon in summer. The findings guide BIPV application in the built environment and cast light on the construction of low-carbon neighbourhoods.