Performance evaluation of a light shelf with a solar module based on the solar module attachment area

摘要

The lighting energy consumptions of buildings are continuously increasing, and more studies on light shelves, which are natural lighting systems, are being carried out as part of an effort to address this issue. The purpose of this study is to propose a light shelf with a solar module covering only part of the light shelf so that lighting and generation are carried out at the same time, and to verify its effectiveness by conducting a performance evaluation. In order to accomplish these, a full-scale test bed was established in this study, and the performances of lighting systems were compared and analyzed by deriving the lighting energy consumption of the light-shelf according to the solar module attachment area, power generation quantity, and uniformity ratio of illumination. Results suggest that (1) the optimum angle varies for both the light shelf without a solar module for saving lighting energy and the optimum angle for a light shelf with a solar module for increasing the sunlight power generation efficiency; (2) the appropriate variable of the light-shelf with a solar module which is suitable to save the building energy is the light shelf with 66.8% attachment of the solar module and the proper angle of the adjustment is required for summer, intermediate season, and winter respectively; and (3) the uniformity ratio of illumination decreases according to the solar module attachment area on the light shelf with a solar module.