Paper Conference

Proceedings of Building Simulation 2011: 12th Conference of IBPSA


Daylight Distribution In A Building Space: A Comparison Of Real Conditions And Theoretical Sky Models

Dariusz Heim, Eliza Szczepanska

Abstract: Results of measurements and a numerical simulation of daylight distribution are presented and compared. Investigations were conducted for a specific period of time (spring) and European weather conditions. Sky luminousity altered on the day of the analysis as a result of changeable weather conditions and cloud cover. Measurements were taken using an original laboratory stand Heliobox, which is a scale model of a simple rectangular room. It is characterized by constant geometry and changeable materials properties of transparent and opaque surfaces. The post is equipped with nine sensors of illuminance to measure the distribution of luminous intensity in the interiors and outside the Heliobox. Measurement results were obtained for real, changeable weather conditions. The simulation was performed using the Backward Ray Tracing Method and Desktop Radiance computer software. Two basic sky types proposed by the CIE were selected for the simulation: clear and partly cloudy. The greatest difference in the results between the measurements and the simulation was caused by the atmospheric turbidity factor.
Pages: 2718 - 2723