Anidolic daylighting system for efficient daylighting in deep plan office building in the tropics

Abstract

Daylight is a natural resource for space illumination. Providing more available daylight in buildings is highly desirable, not only for energy efficiency but also to enhance the occupants’ performance and well-being. Daylight through window is common solution to lit the indoor space, but only provides limited depth of room space. Anidolic Daylighting System (ADS) is one particularly promising technology to be used for transferring daylight into deeper interior spaces. This research determines the ADS variables that are applicable under tropical climate according to modified duct shapes, duct width, duct length and distributor configuration. Experimental scale model and Integrated Environmental Solutions (IES) computer simulation were employed in conducting the research. Physical scale model (1:10) was used to validate the simulation tool and to determine the appropriate orientation. Subsequently, the ADS was simulated in different variables of duct shapes, duct width, duct length and distributor configuration in open plan office. The analysis of results for daylight quantity was done based on absolute Work Plan Illuminance (WPI), daylight factor and daylight ratio, as well as WPI uniformity for daylight quality.The results illustrated that the ADS performed well for all orientations, but its performance in the South orientation was better than other orientations. It was shown that the developed ADS by rectangular duct shape and three meter duct width can transfer daylight as deep as 12.5m and 20m from window wall in overcast and intermediate sky conditions respectively. Moreover, the results demonstrated that effective daylighting depth could be supported with acceptable performance by developed ADS until 12.5m in both quality and quantity under intermediate sky. The new findings give insights for architects, engineers and built environment scientists to reach the complete potential of ADS in visual comfort as well as energy saving.