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

ABSTRACT 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. Although 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.