Cost-effective controlled illumination using daylighting and electric lighting in a dual-function prism light guide

We have developed a system that enables both daylight and electric light to be efficiently delivered to core areas of a building. Daylight is directed into the building by means of a new and cost-effective canopy system which collects sunlight and directs it into the dual-function luminaire. It efficiently transports and distributes the light along its length, and when the amount of daylight is insufficient, auxiliary electric light is automatically provided by fluorescent lamps. This paper focusses on the prototype illumination control system and its performance.