Energy Storage Science and Technology ›› 2021, Vol. 10 ›› Issue (5): 1514-1523.doi: 10.19799/j.cnki.2095-4239.2021.0337

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Dynamic regulation and control of the discharge process in compressed air energy storage system

Yang LI1,2(), Xinjing ZHANG2,3(), Jianfei SONG1, Xiaoyu LI2,4, Huan GUO2,3, Yujie XU2,3, Haisheng CHEN2,3   

  1. 1.China University of Petroleum, Beijing 102249, China
    2.Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China
    3.University of Chinese Academy of Sciences, Beijing 100049, China
    4.North China Electric Power University, Baoding 071003, Hebei, China
  • Received:2021-07-13 Revised:2021-07-26 Online:2021-09-05 Published:2021-09-08
  • Contact: Xinjing ZHANG E-mail:2019215349@student.cup.edu.cn;zhangxinjing@iet.cn

Abstract:

Compressed- air energy storage (CAES) is considered the most promising large-scale energy storage technology; however, CAES systems are faced with complex operating conditions, including pressure change in the air storage chamber and input/output power changes. Because of the demand for off-design conditions of CAES systems and the limitations of low control accuracy and large pressure loss in the throttle valve decompression regulating the inlet pressure of turbines, a pressure control unit combined with the valve combinations and expansion tank is proposed herein to regulate the inlet pressure of turbines and meet the output power demand. A thermodynamic model of a 10 MW CAES system with thermal storage integrated pressure control unit was established. Then, the variations of important parameters, including pressure, temperature, mass flow rate, and power, with time in the charging and discharging processes were investigated. Furthermore, the mechanism and effect of the pressure control unit combined with the valve combination and expansion tank in regulating the inlet pressure of the turbine were assessed. Compared with the throttle decompression mode, the total exergy destruction of the pressure control unit in the discharge process was reduced by 1.56×108 J, and the energy storage efficiency and density was increased by 0.24% and 0.04 MJ/m3. The pressure control unit can smoothly regulate the inlet pressure of the turbine, which ensures the stable and efficient operation of the CAES system and improves the comprehensive performance of the system.

Key words: compressed air energy storage system, discharge process, dynamic control, pressure control, system performance

CLC Number: