Building-integrated photovoltaics (BIPV): A mathematical approach to evaluate the electrical production of solar PV blinds

Lower prices for photovoltaic systems lead to the spread of building-integrated photovoltaics (BIPV). In this paper, a simple method is proposed to evaluate the electrical power produced by Solar Photovoltaic Blinds (SPB). The equations allow to assess slat mutual shading and view factors and are applicable to any slat inclination, any orientation and any geometry. The possibility that the PV layer does not entirely cover the lamella is also considered. A parametric study is performed to evaluate the impact of geometric factors on the annual yield. The paper shows that 1) The south-east (or -west) orientation provides maximum electrical production. 2) Automating closing PV blinds in summer, when room is unoccupied, allows to increase electricity production by approximately 9% for the south, east and west exposures and 16% for the north exposure. 3) There is a slat distance/width ratio that maximizes the annual electricity produced. It depends on the handling strategy and is about 0.6 for energy optimizing methods and 0.7 for standard uses. 4) Solar tracking that maximizes the radiation entering the room in winter significantly reduces electricity production. 5) The reflectivity of the back of the slats has a little influence on the annual production (up to 5%).

Automated summary

A simple method is proposed in this paper to evaluate the electrical power produced by Solar Photovoltaic Blinds (SPB), considering slat shading and view factors as well as the possibility of partial PV coverage. A parametric study shows that the south-east (or -west) orientation provides maximum electrical production and automating closing PV blinds in summer can significantly increase electricity production. There is an optimal slat distance/width ratio for maximizing annual electricity production and solar tracking in winter reduces electricity production. The reflectivity of the back of the slats has a minor influence on the annual production (up to 5%).