Thermodynamic Assessment of High-Parameter Transcritical Cycle Enabled by CO2–SO2 Mixture

High-parameter transcritical CO2 power cycle is regarded as one of the most promising energy conversion systems owing to its high efficiency and compactness. However, it is possible to further improve the thermal efficiency and reduce the size of components by adding CO2 binary mixtures. In this study, a comprehensive thermodynamic analysis of the high-parameter transcritical power cycle enabled by CO2–SO2 mixture is conducted. Simulation results indicate that thermal efficiency increases with the SO2 mass fraction, while specific work does the opposite. And thermal efficiency increases abruptly as the SO2 mass fraction is higher than 0.2. However, thermal efficiency decreases with the SO2 mass fraction at higher maximum pressure. Additionally, system at a higher minimum temperature is more sensitive to SO2 mass fraction. This preliminary research will serve as a guideline for the optimization of transcritical power cycle enabled by CO2–SO2 mixture at design and off-design conditions.