Performance Optimization of Building Facade Floodlighting under Dynamic Sky Luminance

Abstract

With the continuous progress of urbanization and the rapid development of building facade floodlighting, problems such as excessive lighting, serious light pollution, and high energy consumption are becoming increasingly prominent. In this paper, three methods comprising field measurement, questionnaire survey, and energy-efficiency simulation were integrated to develop the floodlighting luminance control curve of a building facade at night and also to carry out an energy-efficiency analysis. Through the field measurement of the floodlighting of the building facade, combined with the method of scene simulation, several virtual combined scene pictures with different sky luminance and different floodlighting luminance of the building facade were made. Furthermore, the optimal floodlighting luminance range as the sky luminance varies was obtained in the form of a questionnaire when the virtual scene pictures were presented on a computer. Then, the floodlighting luminance control curve with the decrease of the sky luminance was developed to achieve the purpose of reducing energy consumption. Finally, energy efficiency analysis of the lighting control curve was undertaken. The result revealed that when the sky background luminance is 8.98–0.51 cd/m2, the recommended floodlighting luminance range of the building facade is 6.13–4.44 cd/m2. What is particularly interesting is that the energy-saving effect is remarkable, and the energy-saving rate at each time is greater than 15%.