Paper Conference

Proceedings of SimBuild Conference 2012: 5th conference of IBPSA USA


Preliminary Evaluation of a Daylight Performance Indicator for Urban Analysis: Facade Vertical Daylight Factor per Unit Floor Area

Ji Zhang, Chye Kiang Heng, Lai Choo Malone-Lee, Yi Chun Huang, Patrick Janssen, Daniel Jun Chung Hii, Ibrahim Nazim
Centre for Sustainable Asian Cities, School of Design and Environment, National University of Singapore
School of Design and Environment, National University of Singapore
Department of Architecture, School of Design and Environment, National University of Singapore

Abstract: Daylight potential for interior spaces has been one of the primary concerns of building performance simulation and various performance indicators have been proposed for interior daylighting quality evaluation. However, interior daylight simulation on urban scale is time consuming and might be affected by a variety of factors. There is the need for measurement on urban scale that can provide relatively efficient and precise estimation of interior daylight potential. A daylight performance indicator for urban analysis was proposed: facade Vertical Daylight Factor per unit floor area, which is calculated as areaweighted total facade Vertical Daylight Factor divided by total floor area. Numerical simulation was conducted across 20 generic forms and 4 different density scenarios. The results showed a strong and positive correlation between the proposed indicator and the reference indicator of interior daylight potential, i.e. area-weighted average horizontal Daylight Factor at work plane height. The utility of the proposed daylight performance indicator lies in its efficiency of simulation for urban scale of analysis and, therefore, the impacts of geometry, spatial arrangement and envelope material properties of urban built forms on interior daylight potential can be evaluated efficiently in the early planning stage. The limitations of this study and potential future explorations are also addressed.
Pages: 638 - 646