Field Performance of Daylight-Linked Lighting Controls
A. Galasiu, M. Atif and R. MacDonald. IES Conference Proceedings, Ottawa, Ontario, August 5-8, 2001, pp. 207-215Review by Scott Schuetter, Energy Center of Wisconsin:
This paper evaluates the performance of photosensor-controlled electric lighting under different configurations of office spaces. Four offices spaces in Ottawa, Canada were studied, each having a floor area of 14 m2 (150 ft2), height of 3 m (9.8 ft), and an occupied schedule of weekdays from 8:00 am to 5:00 pm. The offices each have a high visible transmittance view window and a low visible transmittance clerestory window along with 2 two lamp, 32 W, T8 fluorescent lamps. This equates to a lighting power density of 9 W/m2 (0.84 W/ft2). The electric lights were controlled to a work plane illuminance of 570 lux (57 fc). Two of the offices had electronic dimming ballasts, while the other two had on/off controls. One of the "dimming" offices and one of the "on/off" offices had motorized blinds tied to the photosensors. The results were preliminary at the publishing of this paper. However, the results did show that adding static blinds increased the electric lighting usage by between 40 and 45% for the "on/off" system and between 30 and 35% for the "dimming" system. Further, controlling the blind angles via the photosensors showed only a 10% increase in electrical usage.