Computational simulations for predicting vertical daylight levels in atrium buildings

This paper investigates the impact of well geometry and surface reflectance on vertical daylight levels in atria with square forms under a CIE standard overcast sky. By reviewing some previous investigations and comparing with scale model measurements the vertical daylight factor calculated using Radiance are validated. More simulated vertical daylight factors for a very wide range of atrium geometries and reflectances are given. From the results the attenuation and distribution of the vertical daylight levels on the wall of a square atrium with different reflectances are displayed. Also, the comparisons between simulations and two analytical theories have been performed. Finally some conclusions for supporting daylight design in atria are presented.