The calibration and error analysis of an artificial mirrored sky converted to a clear sky luminance distribution

Abstract

An inexpensive conversion of a mirrored artificial sky from an overcast sky source to a clear sky source allows more extensive model investigation. For a solar altitude angle of 40°, the model sees the relative CIE standard clear sky luminance distribution away from the sun caused by a low perimeter source illuminating a cloth drape covering the mirrored walls. Problems in calibrating the “sky” are explained and compared to a model in a similar real sky and a computer calculation. The errors due to a shifts in angular relationship to the luminance distribution of a close artificial sky source are calculated for different room locations, window types and model sizes.