Solar lighting is considered as a promising technique, which has huge potential to energy conservation and help to relax the mood of residents in the building. However, existing solar lighting systems used a filter to allow only visible light (shortwave) entering buildings and all the other energy contained in the longwave of the solar was released into the surrounding air, which caused the low efficiency of solar energy utilization and the high costs due to such a filter. It is not beneficial for promoting the market application of solar lighting technology. In this paper, a solar lighting-heating dual-effect system was developed which uses a hollow filter that filled by nanofluids to separate the longwave and shortwave of the solar. Based on the spectral selectivity of nanofluids, this system can utilize solar energy in different wavelengths separately. A series of tests were conducted and results suggested that the solar energy utilization efficiency of this system was much higher than traditional solar lighting systems.
Keywords Solar lighting, Nanofluids, Spectral selectivity, Experimental investigation