Illuminance of the working plane in attic spaces under different exterior daylight conditions

Kristián Kondáš

Abstrakt

The assessment of interior daylight conditions, under the current Slovak standards, is based on the Daylight Factor concept. It means that the worst exterior daylight conditions are reflected in calculations, represented by the CIE overcast sky. Since this evaluation criterion was adopted, several decades have passed. Because the overcast sky is not the only sky type observable in nature, the development of a new criterion, based on photometric variables, e.g. illuminance in lux, became necessary. This article presents a study which investigates the relation between relative and absolute illuminance, in specified points on the working plane illuminated by the standard overcast and clear sky.

Słowa kluczowe: daylighting, attic room, illuminance, overcast sky, clear sky
References

STN 73 4301: 2005, Budovy na bývanie (Dwelling buildings), SÚTN, Bratislava 2005.

STN 73 0580-1: 1987, Denné osvetlenie budov. Časť 1: Základné požiadavky (Daylighting in buildings. Part 1: Basic requirements), ÚNM, Praha 1987.

STN 73 0580-2: 2000, Denné osvetlenie budov. Časť 2: Denné osvetlenie budov na bývanie (Daylighting in buildings. Part 2: Daylighting of residential buildings), SÚTN, Bratislava 2000.

Perez R., Seals R., Michalsky J., All weather model for sky luminance distribution – preliminary configuration and validation, Solar Energy, vol. 50, no. 3, 1993, 235-245.

Kittler R., Darula S., Perez R., A new generation of sky standards, Proc. LuxEuropa Conf., Amsterdam 1997, 359-373.

ISO 15409:2004/ CIE S 011/E:2003. Spatial distribution of daylight – CIE Standard General Sky, 2004.