Daylight Performances of Atrium Buildings for Different Roof Configuration Under Malaysia Sky Conditions

Abstract

The research endeavours to fill the identified gap in the field’s knowledge on daylighting in atriums, specifically under tropical sky conditions. The atrium’s form, roof configurations, building orientation, roof transmittance, internal surfaces reflectivity, and grazing areas are the key elements in the daylighting design of atrium buildings. Daylight availability in an atrium has been researched extensively using different techniques and models. This paper presents substantial findings from a virtual simulation exploration. Four models were used to perform the daylighting performance analyses involving field experiments and computer simulations (IESRadiance). The models used different roof fenestration designs and structural truss systems (flat, pitched, pyramidal-gridded and saw-tooth roofs) simulated for substantial virtual verification and investigation. The Daylight Factor/Daylight Ratio (DF/DR) on horizontal surfaces under different types of sky conditions at different times of day and different days over a period of one year were obtained. The illuminance levels were quantified for the unique circumstances of intermediate sky conditions. They show a generally linear relationship and a good degree of correlation with the overall reduction of daylight levels in the atrium. Internal roof obstructions created a relatively constant attenuation of daylight compared with the clear unobstructed roof for the four structured roofs. The discrepancy of light distribution was increased if measured between the unobstructed atrium well with complex configurations. This work has paved the way for more design strategies using complicated atrium roof fenestration constructions to be analysed with accuracy while combining aesthetics with energy efficiency.