Supercritical CO2 Brayton cycle: Intelligent construction method and case study

Abstract

The supercritical CO2 Brayton cycle is considered to be a potential alternative cycle to solar and nuclear energy because of its high efficiency and compactness. However, a challenge on collaborative optimization of parameters and structure in this field is still highly depending on engineering experiences or simplified calculation. In this paper, an intelligent construction method of supercritical CO2 Brayton cycle is proposed, and a two-layer algorithm is designed to solve such a problem. To simplify the cycle, the Brayton cycle is divided into heat transfer part and basic configuration part. Then, based on free-superstructure method, the cycle could be established through a combination of thermodynamic processes. After the accuracy and reliability of the algorithm are verified, three cases are studied and then optimized with the intelligent construction method, the specific work is increased by 47.97 kJ/kg, 46.50 kJ/kg, 42.59 kJ/kg, respectively. The best basic configuration is reheating and inter-cooling Brayton cycle, which is selected from all possible structures generated by no more than two elementary cycles, instead of studying the mechanism of the cycle as previous studies. Finally, the heat transfer network is designed according to the information of the hot steams and cold streams. The study would provide a new viewpoint to design of such cycles based on integration of computational intelligence in thermodynamic field.