Performance analysis of a concentrating spectrum splitting photovoltaic-thermoelectric hybrid system based on radiative sky cooling

To achieve efficient full-spectrum solar utilization, this work proposes a novel hybrid system (SS-CPV-TEG-RSC) that integrates spectrum splitting (SS) and radiative sky cooling (RSC) with a concentrating photovoltaic-thermoelectric generator (CPV-TEG). The system is designed for potential 24 h continuous electricity generation. A steady-state thermodynamic model was established and validated to investigate the system performance. The results show that the combination of GaAs cells with Filter 1 (cutoff wavelength at 850 nm) achieves a peak system efficiency of 21.25 % while maintaining a low PV temperature of 301.16 K. Among practical RSC materials, the BaSO4-acrylic coating (RSC1) is identified as the most suitable, offering near-ideal performance. Parametric analysis reveals that increasing the RSC: TEG area ratio improves both daytime and nighttime power output. At a ratio of 25, the system achieves a daytime power density of 1722.63 W/m2 and a nighttime power density of 15.103 mW/m2. In contrast, increasing the selective solar absorber (SSA): TEG area ratio enhances nighttime performance but reduces daytime output, indicating a design trade-off. Comparative analysis indicates that the proposed system achieves a maximum total power output of 13.34 W under equivalent PV temperature constraints. This represents 308 % improvement over the unfiltered CPV-TEG-RSC system. Moreover, it surpasses the fin-cooled counterpart in cooling performance when the RSC: TEG area ratio exceeds 2.85.