液体活塞近等温压缩空气储能过程热力性能评估

In this paper, a dimensionless evaluation model is established based on the container size (a) and spray parameter (b) to realize the accurate and rapid evaluation of the global thermodynamic performance in the near-isothermal compressed air energy storage process with a liquid piston. Research is conducted on the variation of thermodynamic parameters during the near-isothermal compressed air energy storage process. Finally, the significant effect of liquid piston on the compressed air energy storage system is clarified. The results show that, without spraying, the air-side relative temperature changes gently when the dimensionless number of a reaches 120, which indicates that the liquid piston can realize near-isothermal compression. However, a smaller value of a can result in dramatic change of the air-side relative temperature. Under the spraying condition, the near-isothermal compression mainly occurs in the middle stage of the compression process, and the increase of the dimensionless number of b can weaken the effect of a on the air-side relative temperature. The efficiency of near-isothermal compression with a liquid piston can be higher than 95% under ideal conditions, but with a D155-30 water pump under experimental conditions, it can only be 66%.