Advanced exergoeconomic evaluation on supercritical carbon dioxide recompression Brayton cycle

This study proposes a comprehensive understanding of the supercritical carbon dioxide recompression Brayton cycle by means of extending and applying the advanced exergoeconomic method as one of the first attempts. The advantages of this advanced exergy-based method are determining the real potential for improvement of each significant component and considering the interactions among system components, which cannot be achieved by using the conventional method. The unavoidable/avoidable and endogenous/exogenous concepts are introduced, and detailed modeling is performed to calculate exergy destruction and investment costs. The results demonstrate that the unavoidable value of each component is higher than the avoidable value for exergy destruction cost (except for high temperature recuperator). Even under the most optimistic scenario, the total exergy destruction cost can only be reduced by 2199.29 $/h (38.86%), and about half of this avoidable variable is exogenous. According to the results of traditional exergoeconomic analysis, the reactor is recommended as the governing component to improve the cost effectiveness of the cycle due mainly to its highest operating cost (5313.39 $/h). On the contrast, the turbine should have the highest improvement priority owing to the highest value of the avoidable operating cost (1390.88 $/h). The findings provide a novel way to guide the design and evaluation of the carbon dioxide Brayton cycle through benefiting from the advanced exergoeconomic analysis.