Window-to-Wall Ratio as a Mode of Daylight Optimization for an Educational Building with Opaque Double-Skin Façade

Abstract

This study investigates the impact of Window-to-Wall Ratio (WWR) and Shading Coefficients (SC) as passive design strategies to optimise daylight in an opaque brick Double-Skin Façade (DSF) of an education building in Depok, Indonesia. A sample education building was simulated with DiaLux software for calculating the daylight distribution due to WWR on a daily basis during normal office hours. The optimum amount of window size and glazing were investigated for a typical floor plate area of 315.16m2. WWR was considered from 30% to 60% at 10% intervals in a horizontal and vertical expanding method of window. The simulations were performed in two sky conditions (sunny sky and standard CIE overcast sky) on different dates using glazing material of different SC. The primary findings of this study are that 40% WWR with SC 0.42 and 60% WWR with SC 0.95 achieve the best results for the north and south façade respectively of a DSF building.