Direct luminous efficacy for vertical surfaces facing north, east, south and west, for clear skies

摘要

The luminous efficacy model for direct radiation incident on a horizontal surface developed by Robledo and Soler (2000) has been used in the present work to predict the direct illuminance incident on vertical surfaces facing north, east, south and west. Results of the statistical assessment show that this model estimates direct illuminance on vertical surfaces with practically the same accuracy as when used to predict direct illuminance on a horizontal surface.