Abstract:

For the analysis of thermodynamic process of compressed air in underground rock cavern of compressed air energy plant, based on construction of the mass and energy conservation equation of compressed air, a difference method combined with software FLAC3D and analytical model was proposed for the solution of thermodynamic process analysis. The influence of charge and discharge velocity, minimum operating pressure, storage air temperature and type of sealing material on temperature and pressure of the compressed air during operation was calculated. The research results indicate that the temperature and pressure of the compressed air increase during charging period due to the heat exchange between the compressed air and the surrounding rock of the gas cavern and decrease during the high-pressure gas storage phase. Air charged and discharged rate, the minimum operation pressure of the cavern, the inlet air temperature, material characteristics of sealing layer are the main factors influencing on the variation process of compressed air temperature and pressure. Therefore it is necessary to evaluate the influence of above factors on the operation status of rock cavern for the purpose of safe operation of compressed air energy storage plant during design and operation period.

Key words: compressed air energy storage, underground rock cavern, compressed air, thermodynamic process, energy loss