Performance Comparison of Gas Turbine Cycle Combined With Supercritical CO2 Recompression and Regenerative Cycle

With the aim to recover waste heat from a specific micro gas turbine (MGT), and improve the thermal efficiency and the system compactness, simulation models of regenerative gas turbine cycle combined with supercritical CO2 recompression cycle and supercritical CO2 regenerative cycle respectively are developed. The influence of the introduction of the gas turbine recuperator with three cycle coupling methods on the thermal efficiency of the system is discussed. Compare to the micro gas turbine system combined with supercritical CO2 regenerative cycle, the improved system can increase the thermal efficiency and the output power by 3.32 percent point and 10.54% respectively. The impact on system performance of cycle parameters, including split ratio, the maximum temperature of the bottoming cycle, the recuperator effectiveness of the bottoming cycle and the hot side outlet temperature of the intermediate heat exchanger have been analyzed and optimized. From the viewpoints of the thermal efficiency and the heat transfer area, performance comparison between two bottoming cycles with different coupling methods is done. The multi objective optimization study shows that the regenerative gas turbine cycle coupled in series with supercritical CO2 recompression cycle performs better than that coupled in parallel with supercritical CO2 regenerative cycle in terms of thermal efficiency.