Research Progress on Supercritical CO2-Based Mixture Brayton Cycle

ObjectivesThe supercritical CO2 Brayton cycle has the advantages of high efficiency, compact structure, enormous power generation potential, and strong scalability. CO2-based mixtures as working fluids can change the critical point and improve cycle performance, which has been the focus in recent years. It is of great significance to review its research progress for basic theoretical research and engineering application.MethodsA review is conducted on the research progress on the application of CO2-based mixtures in the supercritical Brayton cycle. The types of commonly explored mixed working fluids are summarized. The research on cycle components and structure layout is discussed, and the commonly used cycle performance and operating conditions are analyzed.ConclusionsThe application of CO2-based mixtures can increase or decrease the critical temperature of CO2, but the predicted physical properties range is limited, and experimental data is lacking. The recompression Brayton cycle is a commonly investigated cycle layout, and thermodynamic performance and design conditions are widely focused. It is recommended to strengthen and deepen the theoretical and experimental research on the thermodynamic properties of mixed working fluids, conduct reasonable verification on the compatibility of component materials, and propose the novel cycle structure layout for the different thermodynamic properties of mixed working fluids. Further exploration is needed for the analysis of comprehensive performance and dynamic characteristics of the CO2 mixtures supercritical Brayton cycle.