Impact of BIPV windows on building energy consumption in street canyons: Model development and validation

Abstract

Photovoltaic components have been increasingly integrated into the façades of buildings as a means to enhance their energy efficiency in recent years, yet the impact of using building-integrated photovoltaic (BIPV) windows in street canyons has been rarely studied due to the lack of modelling tools. In this study, we developed a new parametrization scheme for BIPV windows, and incorporated it into building energy simulations coupled with a single-layer urban canopy model. Evaluation against in-situ measurements and EnergyPlus simulation suggests that the coupled model is able to reasonably capture the diurnal profiles of BIPV window temperature, building cooling load, and outdoor microclimate. A set of simulations were conducted to examine the impact of BIPV windows on summertime building energy consumption and outdoor air temperature in different street canyons. Compared to clear glass windows, BIPV windows can reduce canyon air temperature and building cooling load. Temperature reduction is found to increase with window coverage but does not change significantly with canyon geometry. Savings on cooling energy consumption vary between 9.16% and 63.71% for the studied neighbourhood in Phoenix, US, but tend to be higher for open street canyons with north–south orientation and large window-to-wall ratios. The coupled model takes into account the dynamic interactions between building energy consumption and the outdoor microclimate, thus providing insight into the benefit of using BIPV windows at the neighbourhood scale.