50% energy savings with automatic lighting controls

An electronically ballasted lighting control system that was demonstrated at an office building is described. The system demonstrated the energy savings and demand reduction capabilities of a lighting control system designed to exploit all major control strategies, including scheduling, daylighting and lumen maintenance. After nine months of operation, lighting energy savings of approximately 50% relative to previous usage have been consistently achieved. A two-part control photocell, shown to be effective at maintaining light levels at the workplane regardless of the daylight contribution, is presented.<>