Models of Artificial Sky
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8. Models of artificial sky

Model studies can be used to predict daylight penetration into any building. This is the only reliable prediction method in the case of unusual situations, complex geometries or heavily obstructed windows. Model studies can be carried out under outdoor conditions, but the limitations imposed by weather variations can be quite severe.

The artificial sky simulates the standard overcast sky conditions, giving either uniform luminance or the CIE luminance distribution.

There are two basic forms of artificial sky: the hemispherical and the rectangular (Figure 13). The former may be a diffusely reflective opaque dome surface, illuminated from below, or a translucent dome (hemispherical), with lighting mounted behind. The rectangular sky has a luminous ceiling and four strictly vertical walls lined with mirrors. The multiple reflections between accurately parallel opposing mirrors give an infinite horizon effect. The mirror glass absorption through multiple reflections ensures a luminance distribution similar to that of the CIE sky.

Figure 13 Artificial Sky