Assessment and modeling of the daylight efficacy in Thailand

This research aims to study the characteristics of the daylight efficacy in Thailand. With the solar irradiance and daylight illuminance measurement at a station in Bangkok, the statistical data of the hourly mean values of the efficacy of global and diffuse horizontal components were derived. This study explores the variations of daylight efficacy with climate conditions as well as the correlations with some insolation parameters. Evaluation of prediction performances of the efficacy models proposed by various authors show that no model is suitable for Thailand. Therefore, new models for luminous efficacy were proposed for Thailand.