An energy-efficient simulation-assisted lighting control system for buildings

ABSTRACT: We present a prototypical implementation of an energy-efficient daylight-responsive lighting systems control in buildings that makes use of real-time sensing and lighting simulation. The controller application in this system can control the position of window blinds and the status (on/off, dimming level) of the luminaires. It possesses an internal digital representation involving models of the room, the context (sky), and the occupancy. The room model entails information about room geometry, furniture, the location and size of windows as well as the physical properties of room components (such as reflectance and transmittance). The room model provides the basis of system's internal representation and is updated dynamically using a location-sensing system. The sky model is generated on a real-time basis using calibrated digital photography. To provide and maintain the desired performance under dynamically changing internal and external conditions, the proposed control system operates as follows: i) At regular time intervals, the system considers a set of alternative combinations of the states of control devices for the subsequent time step; ii) These alternatives are then assessed via simulation; iii) The simulation results are compared and ranked according to the preferences specified by the occupants and/or facility manager to identify the candidate control state with the most desirable performance