Utilizing Daylighting Controls in a Manufacturing Facility

Opportunities exist to reduce artificial lighting in manufacturing facilities which have skylights and/or fenestration that provide sufficient quantities of daylight to the work space. Using photometric sensors to measure the illuminance in the space, artificial lights can be automatically switched off during periods when sufficient daylight is available. Daylighting controls used in commercial buildings often use dimmable ballasts with fluorescent lights. Most fluorescent lighting used in manufacturing facilities use high output ballasts which are nondimmable. The preferred method for reducing artificial lighting output is to switch the lamps off. For multi-lamp fixtures such as six-lamp Super T8’s, ballast/lamp configurations are either 2-4 or 3-3, thus giving rise to various stages of lighting reduction. This paper examines these lighting control strategies for a 90,000 square foot manufacturing facility in Iowa. Using the EnergyPlus building energy simulation code, annual lighting energy savings associated with utilization of daylighting were computed for the building. Results showed that the 24 switching control strategy provided better energy reduction opportunity compared to 3-3 switching control.