An isobaric compressed carbon dioxide system operating at high temperature

Compressed carbon dioxide energy storage has attracted considerable academic interest due to its benefits, including high efficiency and low investment costs. This paper investigates an isobaric carbon dioxide energy storage system and establishes a thermodynamic model to evaluate its system performance. The results indicate that higher pressure in the carbon dioxide high-pressure storage tank can increase the energy density of the system; however, it will reduce the system's round-trip efficiency. Increasing the reheater's preheating temperature during the energy storage process improves the system round-trip efficiency and energy density. At the same time, improving the reheater's split ratio, the low-pressure compressor's outlet pressure, and the cooling temperature of the first-stage cooler can improve the system round-trip efficiency and energy density.