Assessment of daylight performance of a commercial office space in hot, arid climate for enhanced visual comfort conditions

Abstract

Daylight penetration into the interiors not only reduces the artificial light requirement but also enhances the well being and in turn, productivity of occupants in a building. The spaces designed with daylight-artificial light integrated schemes thus satisfy the dual objective of minimum energy consumption and maximum comfort of occupants. However, direct solar radiation poses some significant challenges to daylighting such as glare and visual discomfort in regions with hot, arid climate. Visual comfort conditions for the occupants can be assessed by lighting simulation tools. This article presents the results of a simulation study, aimed to identify the most appropriate shading strategies for an office space located in hot, arid climate of Abu Dhabi, UAE. Daylight factor, daylight autonomy and useful daylight illuminances were obtained for horizontal shading options with different orientations using Daysim software. The study revealed that horizontal overhangs exhibited best daylight performance when placed on south facade and north-south facades. This paper also observes that the most efficient strategy for horizontal louvers is to have an angle of obstruction at 20°, because such a strategy resulted in the space receiving illuminances in the useful range between 100 to 2000 lux, indicating significant reduction in glare and visual discomfort for the occupants. The article's ultimate objective is to highlight the use of daylight simulation tools to assess and improve the daylight performance of building interiors in hot, arid climate so that such studies serve as a guide to architects and designers to design spaces that are optimally day lit.