| Keywords |
Control performance; Daylight dimming system; Perimeter zones; Daylight glare probability; Sky; Light output; Lighting energy |
| Abstract |
This study examines the control performance of a daylight dimming system in two perimeter zones of office space. Computer simulations using Radiance were conducted to predict daylight illuminance and daylight glare probability(DGP). A series of computation procedures were performed to predict final dimming levels of lighting fixtures controlled by the system. Results indicate that DGP values under overcast sky conditions varied within acceptable ranges.
The differences between actual and ideal light outputs in the zone facing south-east were less than those in the zone facing north-west. The differences under overcast sky were greater than those under clear sky. The 45o blind conditions should be avoided under overcast sky to achieve acceptable dimming controls. The success of control occurred more frequently under clear sky than overcast sky. Lighting energy savings achieved by the best control performance ranged from 67.46% to 86.11%. Coefficients of determination between workplane and photosensor illuminance due to daylight ranged from 0.8146 to 0.9590 and from 0.8737 to 0.9802 under clear and overcast sky, respectively. |