Combined Sunlight and Occupancy Dynamic Lighting System Design in Offices

A comfortable and healthy lighting environment can improve people's work efficiency, and can avoid physical damages caused by an uncomfortable lighting environment. However, most offices still face problems with lighting-related energy saving and comfort. To resolve these problems, this study proposes a lighting control system that takes sunlight and occupancy as input and the dimming coefficient K ( 0=K=1) of lamps as output. The system establishes a linear mathematical model among sunlight, occupancy, the illuminance component of adjacent lamps, and the dimming coefficient through an algorithm and uses the Matlab least squares method to obtain the optimal dimming coefficient of each lamp. The lighting design software DIAlux was used to investigate the lighting environment under the control system. The results show that under the control of the system, the illuminance of the occupied and unoccupied working surfaces reaches 500 and 300 lx, respectively, and the uniformity of illuminance is greater than 0. 7. Therefore, the control system solves the problem of low uniformity of illuminance in the daytime. In terms of satisfying the office lighting needs, the energy-saving efficiency of the control system in the daytime and nighttime reaches 66% and 14%, respectively.