The assessment of vertical daylight factors across the walls of atrium buildings, Part 2: Rectangular atria

This study investigated the impact of well geometry and surface reflectance on vertical daylight factors on the walls of rectangular atria under a CIE standard overcast sky. The vertical daylight factors predicted using the modelling software Radiance were validated by artificial sky scale model measurements. More simulated data of vertical daylight factors for a very wide range of rectangular atrium geometries and surface reflectances are presented. From the results the variations of the vertical daylight factor on the walls of rectangular atria were assessed and some empirical functions were derived. Initial guidelines for supporting design are presented