A Hemispherical Sky Simulator for Daylighting Model Studies

Light measurements in scale models provide a powerful design and analysis tool for quantitative and qualitative daylighting studies. Models can be measured outdoors, but to facilitate measurements under standard sky conditions and for situations where reproducible results are desired without extensive manipulation of measured data, an indoor sky simulator is essential.

This paper describes the design of a 24-foot-diameter hemispherical sky simulator recently completed at LBL. The goal was to produce a facility in which large models could be tested; which was suitable for research, teaching, and design; which could provide a uniform sky, an overcast sky, and several clear-sky luminance distributions, as well as accommodating an artificial sun.

Initial operating experience with the facility is described, the sky simulator capabilities are reviewed, and its strengths and weaknesses relative to outdoor modeling tests are discussed.