Thermodynamic Analysis and Optimization of a Novel Cogeneration System: Combination of a Gas Turbine with Supercritical CO2 and Organic Rankine Cycles

Thermodynamic analysis of a novel combined system which is combination of methane fired gas turbine cogeneration system (CGAM) with a supercritical CO2 recompression Brayton cycle (SCO2) and an Organic Rankine Cycle (ORC) is reported. Also, a comprehensive parametric study is performed to investigate the effects of some important parameters on the performance of the proposed system. Finally, a thermodynamic optimization is done to maximize energy and exergy efficiencies. The results showed that, the energy and exergy efficiencies are maximized at particular compressor pressure ratios and the values depend on the operating parameters of the system. Energy and exergy efficiencies are determined to be 85.33% and 54.18%, respectively, for the proposed system under the base condition. Moreover, the parametric study showed that in addition to the operating parameters of the system, ambient temperature has also an important effect on the system performance as energy efficiency increases and exergy efficiency decreases with the ambient temperature increment.