Daylighting in atrium building: a study of the influence of atrium façade design

Abstract

Atrium spaces have the potential to make vital contribution to the sustainable strategy and consequently ecodynamics of a building. The environmental benefi ts in terms of daylight, natural ventilation, and heating that an atrium offers are widely recognised. Daylight availability in an atrium space is generally high; however, this may not necessarily be true for the adjoining spaces. Previous studies indicate that the daylight performance of the adjoining spaces can be improved through the design of atrium facades, whereby there is a progressive increase in the fenestration from the upper to the lower fl oors. Therefore, this paper seeks to systematically investigate the effects of different atrium facades design characterised by varied distribution of fenestrations on daylight (DFs) in an atrium and horizontal penetration of daylight in its adjoining spaces under overcast sky conditions for a four sided, top-lit, square atrium building of Well Index (WI) 1.25. Studies were undertaken using computer simulation software programs ECOTECT and RADIANCE with the objective of understanding the infl uence of facades and providing guidelines for facade design to create optimal daylighting conditions in the adjoining spaces. Three main curves were developed, each of which included fi ve options of 20%, 30%, 40%, 50% and 60% openings on top fl oor with a progressive increase in openings and 100% opening on the ground fl oor. Results demonstrate that facade compositions have a very limited infl uence on daylight in the adjoining spaces offering very little benefi ts to the lower fl oors, where daylight is critical. But increase in opening on the top fl oor may increase DFs signifi cantly on the top two fl oors. For this study, the option of 60% opening on top fl oor with progressive increase to 100% opening on ground fl oor provided the best results.