Exergoeconomic Analysis and Optimization of a Supercritical CO 2 Cycle Coupled with a Kalina Cycle

A novel combined cycle system comprising of a supercritical CO2 (sCO2) cycle and a Kalina cycle is proposed in this paper. Exergoeconomic comparison between the combined sCO2/Kalina cycle and the sCO2 cycle is investigated. The exergoeconomic models are established, and detailed parametric analyses are conducted for both cycles to reveal the influence of selected decision variables on cycle performance based on the self-build thermodynamic simulation platform. Besides, the parameters of both systems are optimized utilizing the exergetic efficiency and total product unit cost as the objective functions through genetic algorithm (GA). The results reveal that there is an optimal main compressor pressure ratio, an evaporating pressure, and a Kalina turbine inlet temperature that contribute to better system performance. A lower pinch point temperature difference in evaporator and a higher ammonia water mass fraction are beneficial to operation. The nuclear reactor and the sCO2 turbine are the most and second important components from the view of exergoeconomics. The total product unit cost and exergetic efficiency of the combined sCO2/Kalina cycle are 5.50% lower and 8.02% higher than the values for the stand-alone sCO2 cycle.