Spectral‐Splitting Photovoltaic‐Thermal Solar Collectors Using Selective Hybrid Liquid‐Solid Optical Filters

Photovoltaic-thermal (PVT) solar collectors offer a promising solution for the co-generation of electricity and heat. Here, we
investigate a spectral-splitting PVT collector that integrates a selectively-absorptive hybrid liquid-solid optical filter (LSOF). The LSOF offers a stable and efficient alternative to conventional nanofluid-based optical filters for spectral-splitting PVT collectors. Two photovoltaic (PV) configurations are examined—a silicon (Si) solar cell operated under non-concentrated sunlight, and a gallium arsenide (GaAs) solar cell operated under concentrated sunlight. A Fresnel lens with a geometric concentration ratio of 100 is employed to focus sunlight onto the LSOF, which selectively absorbs ultraviolet and sub-bandgap infrared radiation for heat generation. The remaining solar spectrum is transmitted to the PV cells for electricity generation. This configuration enables fluid temperatures of up to 86.8◦C, while maintaining the PV cell temperature as low as 38.2◦C, demonstrating effective thermal decoupling between the PV and solar thermal absorber. The PV cells have electrical efficiencies of 7.9% for the Si cell and 5.7% for the GaAs cell. ... mehrAlthough the efficiency and output heat temperature of the current LSOF-based PVT collectors remain modest owing to optical losses and elevated temperatures, the system demonstrates the potential of hybrid optical filtering for solar co-generation.