Photoelectric control of daylight-following lighting systems (Daylight-sensing photocell placement)

Technical Report · Wed Feb 01 04:00:00 EST 1989

DOI:https://doi.org/10.2172/7251355· OSTI ID:7251355

Verderber, R. R.; Rubinstein, F. M.; Ward, G.

The ability of daylight-following lighting systems to provide a minimum specified light level at the task surface is influenced by (1) the control algorithm used, (2) the spatial response of the ceiling-mounted control photosensor, and (3) the location of the photosensor relative to task and window. Best performance was obtained with a closed-loop proportional control system controlled by a photosensor, with a large field of view but shielded from direct light from the window. A minimum specified illuminance level could be maintained at specific points on the task surface regardless of daylight condition or room geometry provided that the system gain was properly calibrated to account for the local luminous environment. Open-loop proportional control also performed adequately but offered less precise control than closed-loop systems due to the necessity of using a photosensor that was not shielded from direct window light. Integral-reset systems that were tested performed poorly, but performance could be improved slightly by completely shielding the photocell from direct window light. 8 refs., 45 figs., 4 tabs.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• Sponsoring Organization: DOE/CE; EPRI
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 7251355
• Report Number(s): LBL-24872; ON: DE90007776
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320106* -- Energy Conservation
Consumption
& Utilization-- Building Equipment-- (1987-)
CALIBRATION
CONTROL
CONTROL SYSTEMS
DAYLIGHTING
DIRECT ENERGY CONVERTERS
DOCUMENT TYPES
ENERGY SYSTEMS
LIGHTING SYSTEMS
OPENINGS
PHOTOELECTRIC CELLS
PROGRESS REPORT
WINDOWS