Use of Models and Artificial Skies

USE OF MODELS AND ARTIFICIAL SKIES

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 uniform luminance.

Forms of aritificial sky

There are two basic forms of artificial sky:

(i) Hemispherical artificial sky

(ii) Rectangular artificial sky 0 23

Hemispherical (Dome shaped) artificial sky

The hemispherical artificial sky may be a diffusely reflective opaque dome surface, illuminated from below, or a translucent dome (hemispherical), with lighting mounted behind (Fig. 3.14).

The rectangular artificial sky has a luminous ceiling and four strictly vertical walls lined with mirrors. The multiple reflections between accurately vertical walls lined with mirrors give an infinite horizon effect.

The mirror glass absorption through multiple reflections ensures a luminance distribution (Fig. 3.15).