Thermodynamic Performance of Solar Full-Spectrum Electricity Generation System Integrating Photovoltaic Cell with Thermally-Regenerative Ammonia Battery

The combination of photovoltaic (PV) cells with a thermoelectric subsystem has received considerable attention as a promising method for improving the overall solar electrical efficiency of full-spectrum solar energy. Previous studies have focused on improving solar electrical efficiency, while less attention has been paid to solar energy storage and the coupled operation between the PV and thermal subsystems. In this study, a new integrated system combining PV cells with a thermally-regenerative ammonia battery (TRAB) is proposed to convert full-spectrum solar energy into electricity. The TRAB subsystem can unify electricity generation and energy storage of long-wavelength solar energy in a single subsystem. The thermodynamic performance of the proposed system integrating the PV and TRAB subsystems under different operating conditions was investigated. The results showed that if both PV and TRAB electricity is transmitted to users directly, the solar electrical efficiency of the integrated system increased by approximately 10.85% compared with a single PV system under the same solar irradiation. If PV and TRAB electricity is stored in the battery, the solar electrical efficiency increased by approximately 13.55% compared to a single PV system. Considering the time-varying nature of solar irradiation and electrical loads in the case study, when the electricity generated by the proposed system was prioritized for delivery to users, and the excess electricity was stored in the battery, the proposed system met users' electricity demand in real time. An overall solar electrical efficiency of approximately 22.07% was achieved, indicating good stability and performance under off-design conditions for the proposed system. This study provides a new approach to improve the efficiency and flexibility of solar full-spectrum electricity supply.