Thermodynamic Performance Comparison and Optimization of sCO2 Brayton Cycle, tCO2 Brayton Cycle and tCO2 Rankine Cycle

In this paper, to further improve thermodynamic performance of supercritical carbon dioxide cycle, simple/recompression transcritical carbon dioxide Brayton cycle (STBC/RTBC) and simple/recompression transcritical carbon dioxide Rankine cycle (STRC/RTRC) are proposed. Thermal and exergy performance analysis and optimization for the above four transcritical CO 2 cycles and simple/recompression supercritical cycle (SSBC/RSBC) are conducted. The effect of key thermodynamic parameters on those CO 2 cycle performance is studied. Results indicate that the improvements of thermodynamic performance of CO 2 cycle are obvious when transcritical Brayton and Rankine cycle are applied in it. Within the same range of optimization variables, the maximum thermal efficiency improvements of RTRC and RTBC are 4.98% and 3.6%, and maximum exergy efficiency improvements of RTRC and RTBC are 7.08% and 5.13% when compared with RSBC. Moreover, the thermodynamic performances of STBC and STRC are also outstanding than that of SSBC. This work provides a way to further improve the thermodynamic performance of CO 2 power cycle.