Comprehensive analysis of active and passive daylighting towards power savings in an office room

Abstract

A comprehensive method is presented to simulate illuminance distribution for two office room designs with same area of 7.8 m2 each: room 1 has a window whilst room 2 has no window. The integration of passive daylighting system and light emitting diodes (LEDs) is adopted for illuminating room 1, while the integration of active daylighting system and LED lighting is adopted for illuminating room 2. The effectiveness and power savings are analysed for the aforementioned two cases. The impact of using LED lighting to control the illuminance and light distribution (uniformity) of light is also studied. For both cases, simulation was performed for a selected day under three sky conditions: clear sky, mixed sky and overcast sky using a software called DIALux 4.13 to obtain the average illuminance in the rooms and the power saved via the use of active and passive daylighting systems. Results obtained showed that active and passive daylighting systems are both effective for power savings depending on the location of rooms and time of the day. Also, active daylighting system is more effective under clear sky, while passive daylighting system can be effective under clear or mixed sky.