Performance evaluation and parametric choice criteria of a Brayton pumped thermal electricity storage system

• A cycle model of the Brayton pumped thermal electricity storage system is proposed.
• Internal and external irreversible losses are considered.
• Maximum power output and efficiency of the system are calculated.
• Optimum performance characteristics of the system are revealed.
• Rational ranges of key controlling parameters are determined.

A more realistic thermodynamic model of the pumped thermal electricity storage (PTES) system consisting of a Brayton cycle and a reverse Brayton cycle is proposed, where the internal and external irreversible losses are took into account and several important controlling parameters, e.g., the pressure ratio and heat flows of the two isobaric processes in the Brayton cycle, are introduced. Analytic expressions for the round trip efficiency and power output of the PTES system are derived. The general performance characteristics of the PTES system are revealed. The optimal relationship between the round trip efficiency and the power output is obtained. The influences of some important controlling parameters on the performance characteristics of the PTES system are discussed and the optimally operating regions of these parameters are determined.