Estimating the switching frequency and energy saving for daylight-linked lighting on-off controls

Daylighting is an important and useful strategy for enhancing visual comfort and reducing the electricity consumption by light fittings. In a well day-lit space when the available daylight is far larger than the required level, daylight-linked lighting switching controls can provide substantial energy reductions. However, a drawback with the switching control type is the frequent and swift on and off, annoying occupants and shortening the lamp life. This paper analyses the electric lighting energy reductions and switching frequency of an atrium building under different daylight-linked lighting on-off controls. The results are based on field measurement of daylight illuminance and design implications are discussed.