Research on combined solar fiber lighting and photovoltaic power generation system based on the spectral splitting technology

Abstract

Modern buildings tend to be high-rise and dense, and indoor lightings are extensively depending on electricity even on sunny days currently. In addition, for those existing solar lighting technologies in development, only the visible light of solar radiation has been used, with the extra spectral energy dissipated by waste heat. A solar fiber optic lighting and photovoltaic power generation system based on spectral splitting technology (SSLP) is proposed and tested in this study. The sunlight is divided into different wave bands through a spectral beam splitter, where the visible light is used for optical fiber illumination, and the near-infrared radiation is used for photovoltaic power generation. The designed SSLP system is simulated with the Monte Carlo ray tracing method, and then experimentally tested. The effects of structural parameters and tracking accuracy on the optical performances of the system are examined. The experimental results show that the sunlight transmitted to the room using optical fiber is bright and comfortable, with an average lighting efficiency of 15.1 %; meanwhile, the average power generation efficiency of the system is about 6.1 %, reaching one-third of the value of conventional PV modules. When the output luminous flux is converted by the luminous efficiency of fluorescent lamps, the overall average efficiency of the system can reach to 29.5 %; when converted by LED lamps, the overall average efficiency can reach to 25.4 %, which are both more efficient than the conventional PV power generation. Taking the solar radiation conditions in Beijing as an example, when the sunlight collection area of the system is 1 m2, it can provide 8 h of sunlight illumination of 500 lx per day for a room of 19.7 m2, while the daily generated electricity can be provided to the LED lamps to extend the lighting time by 2.5 h.