| Keywords |
Dimming control ; Photosensor sensitivity ; Partial-shielding ; Lighting energy |
| Abstract |
This study examines the control performance of a photosensor dimming control system in a small office according to three different photosensor sensitivity. Computer simulations were performed for the office with a double skin envelope system under various daylight conditions. Horizontal blind was considered to be installed on the external envelope and a retractable fabric shading device was installed on the internal envelope. Three sky conditions recommended by CIE were used at different times of a day and year. A partiailly-shielded photosensor was placed at the center of ceiling. Photosensor with the most sensitive level to daylight failed to achieve target illuminance providing less light output. The sensor with the least sensitive level provided excessive light output and resulted in overshooting the target illuminance. The sensor with medium sensitive level achieved good control performance and successfully provided target illuminance with reduced light output. The correlation between destkop illuminance and photosensor illuminance due to daylight was greater than 0.79. Reasonable lighting energy savings was achieved by the partiallyshielded photosensor with medium sensitivity. |