Effect of façade thickness on daylight performance in a reference office building

Current daylighting simulation practice often ignores the importance of façade thickness, despite its real influence on the total building performance. This research therefore aims to determine the effect of various facade thickness on daylight performance in a simulated reference office. An isolated reference office with an unglazed opening on one of the short façade was taken as case study, modelled and simulated in Radiance and Daysim, using weather data of Bandung, Indonesia. The thickness of the window façade was varied within 0.05~0.50 m, and the following daylight metrics were determined: average daylight factor, spatial daylight autonomy, spatial useful daylight illuminance, simplified daylight glare probability on selected viewpoints, and annual lighting energy demand. Results suggest that variation of façade thickness yields different impacts, which is largely significant on the average daylight factor, but is subtler on the climate-based daylight metrics and lighting energy demand. © 2019 by International Building Performance Simulation Association (IBPSA) All rights reserved.