| Keywords |
Control performance ; Daylight dimming ; Sky conditions ; Control algorithm ; Photosensor |
| Abstract |
This study investigates control performance of daylight dimming control system under various sky conditions in order to examine the influence of daylight conditions on dimming performance. Field measurements were conducted in a full-scale mock-up model to collect actual data and computer simulations were performed to determine light output of fixtures. Results indicate that the variation patterns of desktop illuminance were similar to those of illuminance arriving at window. The direct component of daylight affected photosensor illuminance generating strong reflected components from wall surfaces. Relationship between desktop and photosensor illuminance was stronger than that of between window and photosensor. This implies that desktop illuminance was effective to predict the variation of photosensor illuminance. Compared to overcast sky conditions, dimming control was effective under clear sky and achieved good energy savings. Under overcast sky conditions, excessive dimming occurred due to the influence of electric lighting. It appears that control algorithm or photosensor conditions should be reset in order to block light input to photosensor and generate less dimming from lighting fixtures. |