Optimization and advance thermodynamic analysis of dual stage Co2 power cycle combined to gas turbine

This paper presents a thermodynamic and economic modeling of Rankine cycles (RCs) that use waste exhaust energy of a gas turbine in the power plant of Sirri Island in Iran based on energy, exergy and economic concepts. In addition, the exergoeconomic and advanced exergy analyses were performed. This cycle is composed of a supercritical CO2 Rankine and a transcritical CO2 cycle. Two objective functions, including the most rate of net power generation of the Rankine cycle (as a thermodynamic criterion) and the lowest total purchased equipment cost (as an economic criterion), are considered simultaneously. This model is constructed on the basis of the energy, exergy and economic analysis according to the Total Revenue Requirement (TRR) method. After validating the model, the advanced exergy analysis is performed to split exergy destruction rate into endogenous, exogenous, avoidable and unavoidable parts in order to provide detailed information about the potential improvement of the system components. The final results indicate that the net electric power output of the Rankine cycle and the total purchased equipment cost become 2.31 (MW) and 301473 (US$), respectively. Also, the exergy efficiency and the total exergy destruction of the cycle reach 48.4% and 8757.4 (KW), respectively.