The Estimated Frequencies of CIE Sky Luminance Distributions and the Impact of the Circumsolar Region Using TMY Weather Files

摘要

Solar and daylight availability depend on the dynamics of atmospheric changes during the course of a day. This paper reports on the feasibility of classifying sky luminance distributions and estimating the frequencies of their occurrences for daylight calculations using Typical Meteorological Year Data (TMY) weather files. The basis for these classifications uses sets of sky luminance distributions that incorporate the CIE Standards. This paper examines the impacts of water content and atmospheric turbidity on the circumsolar size within the sky luminance and radiance distributions. The results show that the size of the circumsolar region influences the solar and daylight availability, which may lead to an over or under estimation of the energy used by the building. The use of a specific sky model with a high probability of occurrence contributes to the design of more efficient daylighting systems. The accurate selection of sky models for a given climate region contributes to a better design of daylight harvesting or solar energy collecting system.