Improving Daylight Illumination and Energy Efficiency Using an Atrium in a Mixed-Use Building

Abstract

Commercial /mixed use buildings in which electric lighting consumes more than 40% of all electric energy demands are discovering a changing need for daylight under the impacts of energy costs. Using atrium in a design can provide adequate light levels into the core spaces. This research attempts to bring the interior daylighting illumination levels within a mixed used commercial -residential building in a desired range of comfortable intensity by using atrium in combination with other daylighting strategies. This research aims to achieve adequate daylight, along all the levels in the atrium and also achieve comfortable intensities in the surrounding spaces. A mixed use atrium building on a site in Tucson, Arizona, was designed and investigated for daylight which involved physical model (experimental) study and computer simulation using software Superlite. Problem areas in daylight performance of the design with respect to the desired daylight factors were identified and analyzed to optimize the daylight illuminance to a adequate level. The results reveal that for optimization, the changes in atrium roof geometry works best in combination with other daylight strategies such as window area, window sill height, light shelf, surface reflectance etc. Atrium in combination with other strategies is found to make significant contribution in daylighting the deeper spaces thereby reducing the use of artificial lighting energy.