Correlating daylight availability metric with lighting, heating and cooling energy consumptions

Abstract

This paper examines the relationship between the Daylight Availability (DAv) metric and annual energy consumption. DAv was established as a means of describing indoor daylight sufficiency both for research and practical purposes. To balance daylighting with energy concerns, the specific amount of daylight sufficiency within a space should neither be too low; nor should it be excessive. However, there is little if any notion of what the relationship between a DAv area and the energy used on-site to supply the artificial lighting, heating and cooling systems might be. The aim of this research is to determine if one or more of the DAv areas predicted on the workplane could serve as a proxy for the overall building energy consumption (lighting plus heating and cooling). The office setting is designed to offer a wide range of daylight exposures, depending on the orientation of the fully-glazed façade and that of the perforated solar screen configuration. Results indicated a strong linear relationship between the overlit area and the cooling energy use. Moreover, confining the overlit area to less than 40% at South and less than 50% at North, East and West could help limit the overall energy consumption to less than 120 kWh/m2-year.