The integration of operable shading systems and electric lighting controls
Using daylighting in commercial buildings may significantly reduce electric lighting requirements if appropriate photoelectric controls are used to adjust the electric lighting output according to the available daylight. Prior analysis and results from monitored buildings and scale-model measurements suggest that the selection, placement, and installation of the control photosensor is a difficult task, even with simple non-operable fenestration systems, since the daylight contributions from sun, sky, and ground change continuously. The problem becomes even more complex for fenestration systems that incorporate operable shading devices, because every adjustment changes the system's optical properties. This paper presents results from measurements in a scale model under real skies, designed to better understand the problem of integrating fenestration and lighting controls. The scale model represented a typical office space and was equipped with motorized venetian blinds. Three control photosensors mounted on the ceiling were considered for the operation of the electric lighting system, and two control strategies were considered for the operation of the venetian blinds. Two ground-plane reflectances and two window orientations were examined. Results indicate that the signal from a ceiling-mounted control photosensor shielded from direct light from the window shows the best correlation with daylight work-plane illuminance, regardless of ground plane reflectance or venetian blind slat angle for all slat angles that do not allow penetration of direct solar radiation. Results also indicate that the control strategies of the venetian blinds that were considered for the purposes of this study may result in significantly different slat angles and thus different daylighting work-plane illuminances and electric lighting requirements, especially when the ground-plane reflectance is high. 3 refs., 31 figs., 1 tab.
- Research Organization:
- Lawrence Berkeley Lab., CA (USA)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6509171
- Report Number(s):
- LBL-20536; CONF-861109-6; ON: DE89006612
- Country of Publication:
- United States
- Language:
- English
Similar Records
Improving the performance of photo-electrically controlled lighting systems
Measured daylighting potential of a static optical louver system under real sun and sky conditions
Related Subjects
320106* -- Energy Conservation
Consumption
& Utilization-- Building Equipment-- (1987-)
BUILDINGS
COMMERCIAL BUILDINGS
CONTROL
CONTROL SYSTEMS
DATA
DAYLIGHTING
ENERGY CONSERVATION
ENERGY SYSTEMS
EXPERIMENTAL DATA
INFORMATION
LIGHTING SYSTEMS
NUMERICAL DATA
PHOTOSENSITIVITY
SCALE MODELS
SENSITIVITY
SHADING
STRUCTURAL MODELS