Predicting transmittance, absorptions and reflectance characteristics for the design of transparent dome passive daylight collector

Daylighting systems are a particular type of solar collector which may be used to provide illumination for the interior of a building by directing daylight into the building. Daylighting and thermal loads are very important design issues for passive daylight collector design. A mathematical model has been developed to predict the visible solar transmittance, absorptance and reflectance of a transparent domed passive daylight collector for both direct and diffuse radiation. The model is based on tracking the beam and diffuse radiation transmission through the dome surface. The shape of the daylight collector geometry, among other factors, has an effect on the amount of daylighting contribution and solar heat gains. The optimum design can only be accomplished by a careful understanding of light transmission process though the dome geometry. This paper describes the mathematical modelling for the design of a transparent domed passive daylight collector with a narrow solar light pipe penetrating the roof to provide a high transmission of light from the exterior to the interior of the building.