Paper Conference

Proceedings of BauSim Conference 2010: 3rd Conference of IBPSA-Germany and Austria


A simple method for the derivation of illuminance values from radiance data

Sokol Dervishi, Ardeshir Mahdavi

Abstract: Daylight simulation applications require information on sky luminance distribution. Sky distribution maps can be generated synthetically, but the process requires external illuminance information for calibration purposes. As measured external illuminance levels are not available for many locations, the more widely available irradiance measurements can be translated, using proper luminance efficacy functions, into illuminance values. In this context, the present paper compares five alternative luminous efficacy models for the prediction of external illuminance based on irradiance. The first option is based on a fixed global luminous efficacy assumptions. The other options consider potential dependencies of luminous efficacy on outdoor temperature and humidity ratio. The models are first derived based on a first set of measured data and then test against a second set of empirical observations. Keywords: luminous efficacy, irradiance, illuminance, temperature, humidity ratio
Pages: 495 - 498