A prismatic daylight redirecting fenestration system for southern skies

Daylighting had always played a crucial role in reducing the electric energy consumption in balance with preserving a high quality of illumination. Modern architectural design in densely populated areas would result in inadequate illumination. Such conditions raised the urge of using non-traditional solutions to assist light in penetrating deep dark spaces. Many systems have been designed to serve northern skies with low solar altitudes. This paper clarifies the design process of a light harvesting system for southern skies; however, for higher solar altitudes. The system has been developed using optical analytical equations and the bidirectional scattering distribution function (BSDF) for the system was derived, and simulations were carried out using RADIANCE. A small-scale prototype was manufactured to validate the simulation results and prove the concept of prismatic light redirection. The design turned out to improve the daylighting performance in deep dark spaces. Dynamic daylighting measures such as daylight autonomy and continuous daylight autonomy were used in rating and improvements ranging from 25% to 34% were achieved using the system as compared to traditional glazing.