System Design and Application of Supercritical and Transcritical CO2 Power Cycles: A Review

Improving energy efficiency and reducing carbon emissions are crucial for the technological advancement of power systems. Various carbon dioxide (CO 2 ) power cycles have been proposed for various applications. For high-temperature heat sources, the CO 2 power system is more efficient than the ultra-supercritical steam Rankine cycle. As a working fluid, CO 2 exhibits environmentally friendly properties. CO 2 can be used as an alternative to organic working fluids in small- and medium-sized power systems for low-grade heat sources. In this paper, the main configurations and performance characteristics of CO 2 power systems are reviewed. Furthermore, recent system improvements of CO 2 power cycles, including supercritical Brayton cycles and transcritical Rankine cycles, are presented. Applications of combined systems and their economic performance are discussed. Finally, the challenges and potential future developments of CO 2 power cycles are discussed. CO 2 power cycles have their advantages in various applications. As working fluids must exhibit environmentally-friendly properties, CO 2 power cycles provide an alternative for power generation, especially for low-grade heat sources.