Optimization-based form finding - The effect of bay window’s geometry on natural lighting

The paper investigated the optimization of window geometry for boosting daylight performance. In previous studies, the effects of window size, position, and orientation on daylighting are well established. However, a little attention is paid to the impact of changing the geometrical properties of bay windows on daylight efficiency. The paper presents a parametric exploration of the effects of bay window geometry on natural lighting. It examined the impact of different shapes of bay windows on the daylight availability in a room. A hypothetical case study was conducted to measure daylight for 24 parametrically varied bay window designs in three cardinal orientations (East, South, and West). The sample alters geometrically by differentiating the horizontal angle of each pane. The simulation of cases was run in DIVA plug-in for Rhinoceros and Grasshopper to calculate the spatial Daylight Autonomy (sDA) for each bay window, with and without a shed. The research findings revealed that 66% of 144 simulated cases could efficiently optimize daylight compared to a flat window. The impact of changing bay window geometry on daylight variability is higher in bay windows with and without a shed in the East than in the South and West. The geometrical properties of bay windows, such as symmetry, asymmetry, and reflection, showed different influences on daylight performance. In addition, increasing the projection sizes of the same bay windowpanes has a marginal effect on boosting daylight. Lastly, changing the cardinal direction of most simulated bay window geometries affects their daylight optimization ranking.