The Sky Radiance and Luminance Distributions Estima Ted by Global Irradiance and Diffuse Irradiance

Abstract

Previously ， the daylit environment and the thermal environment were individually examined ． h is necessary to establish a method ofthe ove 旧 11 plan and design， which integrates the daylit and thermal environments fbr the energy conservation ， and to secure the quality ofthe indoor environme 爪 ． Therefore ， a min 戚 e ， realistic model concerning the daylight and the solar radiation caused by the sun and sky is neGessa π y ． Howeve ら the proposal ofthe model by which sky radiance and luminan distributions are integrated is noI seen ． Authors have proposed the numerical e 唖u 飢 ion model conceming the sky luminance distribution and dle sky τadiance distribution ． This paper aims to improve the current melhod of classifying the sky conditions ， and to propose a numerical ¢ quation model by which the sky π adiance and Eum孟 nance distributions are int ¢ grated ． The clear sky index is de 価ned based on the global irradiance ， and the cioudless index is de亜ned based on the cloud ratio ， and 1he sky conditions are classified based on both indices ． The meIhod by which 山 e rel 飢 ive sky luminance and radiance distribuIions are shown by 翫 esar 口 e equation is developed． And the ¢ quations fbr the sky radiance and luminance distributions shown in absolute value are proposed ． Kepmvords． ' Sky radiance