Experimental and Comprehensive Study of a Full-Spectrum Solar Energy Efficient Cascade Utilization System Based on Spectral Splitting and Passive Cooling

Solar photovoltaic (PV) conversion has become a key area in today's energy supply. However, incomplete utilization of the PV cell bandgap results in the conversion of photon energy outside the bandgap into waste heat, reducing the overall efficiency. Improving spectral utilization efficiency and mitigating the effects of PV waste heat are top priorities. In order to solve these problems, this study proposes a full-spectrum solar energy step utilization system that combines spectral splitting with passive radiative cooling. Spectral splitting is utilized to direct photon energy from inside and outside the bandgap to the PV cell and the thermoelectric generator, respectively, and passive radiative cooling is utilized to increase the thermoelectric temperature difference, broaden the spectral utilization range, and improve the energy utilization efficiency. The accuracy of the simulation model was verified through outdoor experiments, and the surface temperature of the PV modules was found to be reduced by 2.59 °C. With the help of the model, the study investigated the effect of environmental factors such as wind speed, humidity and ambient temperature on the performance of the system. This comprehensive analysis demonstrates the potential of combining radiative cooling with full-spectrum solar energy utilization for efficient and high-quality spectral utilization.