Derived energy storage systems from Brayton cycle

Summary: Various energy storage systems (ESS) can be derived from the Brayton cycle, with the most representative being compressed air energy storage and pumped thermal electricity storage systems. Although some important studies on above ESS are reported, the topological structure behind those systems (i.e., derivations of the Brayton cycle) has not been studied, and the underlying thermodynamic ideas still need to be further explored. This paper first introduces the topological structure and the symmetry of ESS and their based Brayton cycles. The formation method of ESS based on paths and separation points is specified. It is found that round-trip path can form ESS directly. Then various ESS formed are compared. Finally, the synergistic effect and gain principle of thermal cycle and ESS are revealed. This work helps to reveal the intrinsic relationship between thermal cycles and ESS, understand the general laws behind ESS, and guide the combination of thermal cycles and ESS.