Thermodynamic analysis and optimization of a novel green hydrogen-electricity-heat tri-generation system based on full spectrum utilization of solar energy

Current research on solar spectrum splitting Photovoltaic-Thermal hybrid systems face issues such as dependence on fossil energy and low efficiency in solar-to-product. To address these issues, this paper proposes a novel hydrogen-electric-thermal tri-generation system that integrates photovoltaic cells power generation with a supercritical CO2 Brayton cycle, which achieves efficient utilization of the full spectrum of solar energy. A thermodynamic analysis and optimization model of the proposed system is established. The three modes of the proposed system are proposed to satisfy the requirements of different productions (hydrogen-electricity-heat, electricity-heat, and hydrogen-heat). A comparison between the proposed system and reference system is conducted, and the results indicate that the solar-to-hydrogen efficiency and solar-to-product efficiency of the proposed system are increased by 0.98%-11.63% and 2.35%-41.61%, respectively. The maximum solar-tohydrogen efficiency of the proposed system at the optimal left cutoff wavelength is 49.8%. The solar-toproduct efficiency of the three operating modes of the proposed system is 77.7%, 80.2%, and 71.2%, respectively. This study offers a novel approach to efficiently utilizing solar energy and achieving zero-carbon hydrogen production.