The Daylight Performance of an Integrated Skylight and Shading Dome for the Tropics

Abstract

This paper evaluates the daylighting performance of an integrated skylight and shading dome with natural ventilation (SDV) for residential buildings in the tropics using the RADIANCE lighting simulation program and the Energy Plus Weather (EPW) file for Bangkok, Thailand. Indoor illuminance levels at work plane height of a simulation model with the SDV was compared to that of from similar physical scale model located in natural environment. A typical unit base case model (1.35 m x 1.35 m x 2.80 m) with a circular translucent opening (60% transmittance, r = 0.175 m) was developed to relate with sizing of available conventional roofing materials and typical residence room’s height. Daylighting performance of the base case based on Daylight Autonomy (DA 300 lux) was compared to the original SDV and the modified SDVs, which the skylight plate replaced with different translucent materials (40%, 50%, and 60% transmittance). The results show that the modified SDVs’ DA are all above 50%. Four typical units of the modified SVD (60% transmittance) were developed to represent an application and compare to a conventional translucent sheet in an extended residence area. The results confirm that the modified SDV has better daylighting quality than the translucent sheet which has similar opening area and light transmittance value (60%). With proper design and material selection, the modified SDV (60% transmittance) could significantly reduce direct sunlight, which is the cause of glare and heat problems for buildings in tropical climates.