Design methodology for optimization of electricity generation and daylight utilization for façade with semi-transparent photovoltaics

Semi-transparent photovoltaics (STPV) have a large potential for integration in fenestration systems, adding the option of solar electricity production while still allowing for satisfaction of daylight needs. This paper studies the potential of using such a technology and examines the impact of changing the photovoltaics (PV) area ratio (ratio of PV coverage to fenestration area) on the STPV façade. It includes a preliminary verification of the workplane illuminance model through comparison with measured data from an experimental office with a specially built fullscale prototype of a window with spaced solar cells in its upper section. The paper will address the issue of optimizing the PV area ratio for a simplified model based on a typical office in Montreal with a 3- section façade. The effect of changing orientation and PV efficiency on the overall net electricity generation (including the lighting load, heat gain from the artificial lighting, and the output of the PV) is presented. The annual simulation results show that a façade with integrated STPV has the potential to improve overall energy performance when compared with opaque PV due to the significant daylighting  benefits even at low transparency ratios.