A new overcast sky simulator was developed in the fall of 2000 at the Faculty of Architecture at NTNU, Trondheim, Norway. During the design process the limits of the mirror box concept as an overcast sky simulator were investigated. One of the limits is uneven distribution of luminance over the surface of the luminous ceiling. The reason for this is the uneven light distribution on the diffusing canvas from the light sources. The diffusing canvas itself may not be a perfect lambertian diffuser either. Another limit is the uneven luminance distribution on the mirror walls due to the stepwise changes of luminance on the mirror walls. The methods for reducing those limits are discussed and described.
Get full access to this article
View all access options for this article.
References
1.
Airy A.An artificial sky chamber for daylighting studies. University of Washington, 1978.
2.
Arnesen H. Performance of daylighting systems for sidelighted spaces at high latitudes. PhD thesis. Trondheim, Norway: Department of Building Technology, NTNU, December 2002.
3.
Baker N, Fanchiotti A, Steemers K.Daylighting in architecture. A European reference book. London: James & James Ltd, 1993.
4.
Bouten E, Rutten AJF. Ontwerp daglichtkamer, Concept Eindverslag and Validatie Radiance. TUW Eindhoven, 1995.
5.
Cooksy C, Loveland J, Millet M, Vagangs A.Limits of the sky. Testing and evaluation of the current state-of-the-art in mirror-box sky simulation. Department of Architecture, JO-20, University of Washington, 1989.
6.
Hecht E.Optics. New York: Addison-Wesley, 1990.
7.
Littlefair PJ.Measuring daylight—the effective use of scale models. Building Research Establishment, Garston, Watford, 1993.
8.
MatWorks Inc. MATLAB Mathematical integration program www.mathworks.com
9.
The Sailcloth Producer: Challenge Sailcloth Inc. 104 East Main St. PO Box 716 Vernon, CT 6066, USA.
