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Sun Tunnels, Tubular Skylights, and Solar Tubes
Sun Tunnels, Tubular Skylights, and Solar Tubes

How to account for daylight from indirect or diffuse sources

Patrick Chopson avatar
Written by Patrick Chopson
Updated over a week ago

Diffuse sources are not going to work right for a daylight simulation in the platform if one makes the hole the same size as the actual source in the ceiling. This is because the reflective coating and prism on the top of the collector focuses the light and does not provide direct sun to the floor. In reality, a solar tube is more like a lighting fixture in that it provides continuous, even light throughout the day. That is, the sun does not move across the space.

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To properly account for a solar tube you will need to determine the combined affect of the solar tube collection and then make a skylight that approximates the affect of that tube. Until we introduce electric lighting, this is an approximate method of accounting for a continuous diffuse light source. As rule of thumb, a skylight about 4 times larger than the diameter of the reflector will give one an equivalent result.

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