Energy Storage Science and Technology ›› 2020, Vol. 9 ›› Issue (3): 892-900.doi: 10.19799/j.cnki.2095-4239.2019.0224

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Cavern volume of CAES system based on energy efficiency analysis

JIANG Zhongming1,2(), GUO Jing1, TANG Dong1,3   

  1. 1. School of Hydraulic Engineering, Changsha University of Science & Technology
    2. Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province, Changsha University of Science & Technology
    3. Open Research Fund of Science and Technology Innovation Platform of Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, Changsha University of Science & Technology, Changsha 410114, Hunan, China
  • Received:2019-10-09 Revised:2019-10-31 Online:2020-05-05 Published:2019-11-05

Abstract:

The volume of an underground air-storage cavern is a basic parameter in the planning and engineering of large-scale compressed-air energy-storage power stations. The volume of an isochoric air-storage cavern must be accurately matched with the installed capacity of the power station. This work calculates the energy storage of compressed air in the cavern and determines the energy storage efficiency of the cavern. Based on the energy storage efficiency, it calculates the cavern volume and finally derives the efficiency of the expansion device and the power generation efficiency of a generator set. To assess the correctness and rationality of the calculation method, the main factors affecting the energy storage efficiency and volumetric quantity of the cavern were quantified in numerical examples. As the operation cycles proceeded, the energy storage efficiency gradually improved and the variations decreased, reaching stability in the later stage. The energy storage efficiency decreased with increasing leakage amount of compressed air, and was enhanced by increasing the coefficient of convective heat transfer. The operation pressure difference also increased the energy storage efficiency up to a certain value. Increasing both the storage efficiency and the operation pressure difference reduced the cavern volume that matched the installed capacity. Therefore, to decrease the construction cost of the cavern, the operation scheme should increase the operating pressure and the operating pressure difference as much as possible.

Key words: compressed air energy storage, underground air storage cavern, energy storage efficiency, cavern volume

CLC Number: