Daylighting performance of topside lighting systems under different sky conditions

Daylighting is the controlled access of natural light into a space through windows to reduce or eliminate electric light. Among window systems, topside lighting systems, including monitor, and sawtooth windows, are one of the most popular equipment used to improve lighting quantity. This study aims to evaluate daylighting performance of topside lighting systems under different sky conditions. For this purpose, 1/10 of scale models of the systems were created with the same areas of glazing (10 percent of floor area) on top of the center roof. The scale models were sized 12.0mx12.0mx6.0m (wxdxh). Four types of topside lighting system - toplighting, monitor lighting, sawtooth lighting and sunscoop - were tested and compared. The parameters of lighting performance were the light factors. The sky conditions were overcast and clear sky. Based on the results, toplighting systems are recommended for overcast sky condition, with 9.4% light factor. Topside lighting systems, on the other hand, are for clear sky types with variable sky conditions.