Energy Storage Science and Technology ›› 2021, Vol. 10 ›› Issue (5): 1796-1805.doi: 10.19799/j.cnki.2095-4239.2021.0330

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Performance of pumped thermal electricity storage system based on reverse/forward Brayton cycle

Han ZHANG1,2(), Liang WANG1,2(), Xipeng LIN1, Haisheng CHEN1,2,3   

  1. 1.Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China
    2.University of Chinese Academy of Sciences, Beijing 100049, China
    3.Nanjing Institute of Future Energy System, Institute of Engineering Thermophysics, Chinese Academy of Science, Nanjing 211135, Jiangsu, China
  • Received:2021-07-12 Revised:2021-07-22 Online:2021-09-05 Published:2021-09-08

Abstract:

Pumped thermal electricity storage (PTES) systems are a novel type of physical energy storage technology with low capital cost, high energy density, and no geographical restriction. In this study, the transient behavior of PTES systems based on the Brayton cycle was explored under cyclic stable state by coupling dynamics analysis method, transient heat transfer, and finite-time thermodynamics. The performance of the two concepts of PTES systems proposed by Isentropic Ltd. and Saipem S.A. company (hereafter, Is-PTES and Sa-PTES system, respectively) was analyzed and compared, and the influence of the working fluid, system maximum temperature, and volume of thermal energy storage reservoirs on the performance of the system are discussed. Under standard operating conditions, the round-trip efficiency of the Sa-PTES system is higher, whereas the Is-PTES system exhibits better output stability. The round-trip efficiency of the Is-PTES and Sa-PTES systems reaches 56.42% and 64.28%, respectively, and the performance of the PTES system using He is the best, followed by that of the system using air, and that of the system using Ar is the worst. Exergy analysis demonstrated that the compressors and expanders account for the highest proportion of exergy loss in the Is-PTES system, which was converted into heat exchangers and thermal energy storage reservoirs in the Sa-PTES system. When the allowable upper limit temperature of the PTES system is low, the performance of the Is-PTES system becomes better than that of the Sa-PTES system. For the Sa-PTES system, better performance can be obtained under high upper-temperature conditions, and it is affected more by the volume of packed beds.

Key words: Brayton cycle, pumped thermal electricity storage, energy storage, exergy analysis

CLC Number: