Sky luminance models: Sensitivity to sky-dome subdivision

Abstract

Up to now the evaluation of illuminances on workplane and luminances of indoor surfaces has been usually performed using the well-known CIE 'Clear' and 'Overcast' standard luminance distributions. However, these models are not always close enough to the real sky conditions that may occur in several climatic zones worldwide. An international effort (IDMP) has been initiated to establish other typical luminance distributions, and different models, as functions of climatic data, have been proposed. Starting from the availability of the standard luminance distributions, this paper presents the first step of development of a daylighting calculation program. A sensitivity analysis of sky dome discretisation was performed with the aim of calculating of horizontal outdoor diffuse illuminances due to the sky component associated with each luminance distribution, and the paper presents the results.

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