01602nas a2200145 4500008004100000024001000041245006500051210006400116260001200180520111500192100002801307700002701335700002201362856007201384 1989 eng d aL-13000aPhotoelectric Control of Daylight-Following Lighting Systems0 aPhotoelectric Control of DaylightFollowing Lighting Systems c02/19893 a
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.
1 aRubinstein, Francis, M.1 aVerderber, Rudolph, R.1 aWard, Gregory, J. uhttps://facades.lbl.gov/publications/photoelectric-control-daylight