Performance improvement of supercritical carbon dioxide power cycles through its integration with bottoming heat recovery cycles and advanced heat exchanger design: A review

In this article, the performance improvement of supercritical carbon dioxide (sCO₂) Brayton cycles through heat recovery and advanced heat exchanger (HX) design is reviewed. The configuration of sCO₂ cycles and the bottleneck of the design of an efficient sCO₂ cycle is first evaluated. It was found that heat rejected in the precooler is a large waste that could potentially enhance the overall sCO₂ system performance. Then integration of the absorption cycle, organic Rankine cycle, and thermal desalination plant to the sCO₂ cycle to recover the waste thermal energy is reviewed and discussed. Results showed that these bottoming heat recovery cycles could substantially improve the overall sCO₂ system efficiency. The combined system of sCO₂/absorption chiller, sCO₂/ORC increases the cycle efficiency to about 78% and 79%, respectively. Also, a combined system of sCO₂/desalination produces about 200 000 m³/day with a cost of less than $1.0/m³. Based on the review, the evaluation criteria are proposed for decision-makers. Another bottleneck of the design of the sCO₂ system is the HXs (recuperators) used in the sCO₂ cycle which are relatively large and negatively affect the cycle compactness and performance. Therefore, various types of recuperators proposed and designed for sCO₂ cycles are reviewed and evaluated. This review highlights the need for further research to enhance heat recovery, reduce the cost of bottoming cycles, and improve the design of HXs.