High temperature solar S-CO₂ and ORC combined Systemcycle Using with low temperature thermal storage

Supercritical CO₂ Brayton cycle (S-CO₂) is kownknown as the most potential type of the next generation of the solar power station. However, its high turbine inlet temperature bring brings difficulties to thermal storage. This paper presenteds a combined S-CO₂ and organic Rankine cycle (ORC) combined system. The system generates power by S-CO₂ part during the day and by ORC part during the night. The powerPower source of the ORC part is the heat releasing of the S-CO₂ part during the day and which is storaged stored. Thereby, the this solar power system could generates power continuously day and night, at the same time, difficulties brought by high temperature to thermal storage can be avoided. Simulating calculation of this paper indicated indicates that siloxanes show better performance than other fluids in this system, the ORC part power output reaches 50% of the whole system power output when the ORC turbine inlet temperature is about 220 -230℃, and the thermal efficiency of this system can be kept above 38%. Researches showed show that the combined S-CO₂ and ORC combined system has the ability to keep high system efficiency, generate power continuously day and night, and avoid thermal storage at high temperature at the same time.