| Keywords |
System performance ; Daylight dimming control ; Open-plan office ; Sky conditions ; Target illuminance ; Lighting energy |
| Abstract |
This study investigates system performances of a daylight dimming control installed in a large open-plan office space with a curtain wall structure. Under a variety of daylight conditions, computer simulations were performed for two zones of the office space which are facing east and west. Results indicate that the changes of photosensor illuminances were strongly influenced by the direct component of daylight under clear and intermediate sky. Overcast sky was a weak contributor to the changes due to diffused components of daylight. For the majority of time periods under all sky conditions, the dimming control system overshot a target illuminance of 750 lx due to insufficient dimmed levels. Reasonable lighting energy savings were achieved under clear and intermediate sky conditions. Overcast sky was not a favorable condition for lighting energy savings due to insufficient daylight. Strong linear correlations existed between desktop and photosensor illuminances by daylight under all sky conditions. Statistical test results imply that reasonable reductions of error variance can be achieved for the correlations. |