Multi-parameter optimization of a concentrated spectral splitting photovoltaic/thermal system: Integrating geometric parameters and spectral allocation

The high-temperature operating environments in solar concentrating systems induce material degradation as well as photovoltaic conversion efficiency reduction. Spectral splitting technology effectively resolves the conflict between photothermal and photovoltaic efficiency in concentrated photovoltaic/thermal systems through wavelength-selective spectral utilization. This study proposed an optimization methodology for geometric parameters and received spectra in concentrated spectral splitting photovoltaic/thermal systems to enhance system efficiency. Modeling analysis of component geometric deviations and optical characteristics identified negative focal length deviation in the spectral beam splitter as most significant to system efficiency. At 5 cm focal length deviation, the system thermodynamic conversion efficiency and system comprehensive thermal efficiency decreased by 9.2% and 24.5%, respectively. System efficiency was positively related to the concentrator reflectance, splitter reflectance in the effective power generation band, and photovoltaic module absorptance. The system optimal design showed that a maximum system thermodynamic conversion efficiency of 24.4% was achieved with spectral beam splitter installation height of 740 mm and a photovoltaic spectral reception range of 436-1072 nm. The concentrated spectral splitting photovoltaic/thermal system demonstrated superior performance in energy harvesting and environmental sustainability compared to conventional solar energy systems. The optimized system design provides theoretical guidance for practical engineering applications in system configuration and installation commissioning.