Using daylighting in highly luminous climates: Visual comfort and performance

Countries having climates of high solar radiation can benefit from favourable natural lighting conditions to achieve energy savings and visual comfort in office spaces. However, potential problems may arise from excessive contrast between the area close to the window and that opposite to it. Uncontrolled access of solar radiation increases thermal loads during summer, affecting air-conditioning systems. Integral glazing/shading systems are rarely considered although they improve overall energy performance and provide visually comfortable uniformity. This work presents a qualitative and quantitative approach to evaluate daylighting systems for such climates. Three systems for a sidelit office space were analysed in an environment of high solar radiation: a single window without external protection, a horizontal lightshelf and a basic anidolic concentrator mounted on the view window. Radiance simulations for different seasons during the year and hours of the day were made on a prototype corresponding to a deep office space typology that includes enhanced reflectance in the surfaces' finishes. The systems are compared for illuminance and glare performance. Recommendations and architectural implications are presented and discussed.