Monitoring of Daylight Controlled Dimming Systems and Occupancy in Three Equivalent Classrooms

Providing a daylight controlled dimming system in a building design can reduce the lighting energy consumption significantly. However, while both the lighting energy savings and the light-on time have a major impact on the payback period of the daylight controlled dimming system, it’s quite difficult to make a true estimation of these parameters. Anyway, it has to be made sure that the energy savings are not at the expense of the visual comfort. This paper presents the results of a 1-year monitoring campaign in 3 classrooms of a school in Belgium in which a daylight controlled dimming system was installed. Aspects regarding both energy savings and visual comfort are examined. Also the results of the monitoring of the occupancy in the classrooms are discussed. The research shows that the occupancy, and thus the light-on time, tends to be low in classrooms. The annual light-on time varied from 567 to 603 hours. The energy savings of the daylight controlled dimming systems in the 3 equivalent classrooms varied significantly, from 18% to 46%. Beside the energetic aspect, the visual comfort due to the lighting systems is even more important. All too often, bad commissioning and a lack of following up the functioning of systems lead to poor performance of the systems.status: publishe