The Impact of Occupant Behavior on Daylight Performance of an Office Room in a Tropical Climate

Abstract

This work explores three patterns of occupants' control of window blinds and the potential influence on daylight performance of an office room oriented to the East. In Natal city (5o S), Northeast coast area of Brazil, windows oriented to East are frequently obstructed by curtains, despite the daylighting and the exterior view. The daylight discomfort leads the occupant to close the blinds. The consequences are obstructed outside view, poor daylight quality and dependency on artificial lighting. This paper assesses the impact on available daylight using parametric analysis based on daylighting dynamic computer simulations run in Grasshopper and Daysim software, and the parameters assessed are window-to-wall ratio (40% and 80% WWR), sky view factor (small and large SVF) and occupant behavior (active, intermediate and passive users). The performance criteria combines Useful Daylight Illuminance (UDI500-5000lux) and illuminance uniformity distribution. Results confirm the role of user behavior on the daylighting performance. The combination of external shading devices, high Sky View Factor (SVF) and high window size can make daylighting user proof for 1/3 of the time, and can double the daylighting performance if combined with an active user.