基于能量梯级利用原理,分别提出了双级储热、三级储热高温预热和三级储热高温再热的三种压缩CO₂液态储能系统的余热回收利用方案。建立了该三种储能系统的数学模型并进行了热力学分析,研究了压力和温度对系统的热力学性能影响。结果表明：采用三级储热高温预热的余热回收利用方案,系统性能最优,设计条件下,循环效率为62.3 %,储能密度为20.6 kW.h/m₃^,比采用双级储热和三级储热高温再热的方案循环效率分别高出1.9 %和4.5 %,储能密度分别高出0.6 kW.h/m₃^和1.4 kW.h/m₃^。此外,增大系统压缩过程压差,合理分配换热器的换热比例有利于系统热力学性能的提升。研究结果为压缩CO₂储能系统效率的提高提供了参考。

Based on the principle of energy cascade utilization, three kinds of waste heat recovery and utilization schemes of compressed CO2 liquid energy storage system, including two-stage heat storage, three-stage heat storage and high temperature preheating and three-stage heat storage and high temperature reheating, are proposed respectively. The mathematical models of the three kinds of energy storage systems are established and thermodynamic analysis is carried out, and the influence of pressure and temperature on the thermodynamic performance of the systems is studied. The results show that: The waste heat recovery and utilization scheme of three-stage heat storage and high temperature preheating has the best system performance. Under the design conditions, the cycle efficiency is 62.3 % and the energy storage density is 20.6 kW .h/m3^{, which is 1.9} % and 4.5 % higher than that of the schemes of two-stage heat storage and three-stage heat storage and high temperature reheating, respectively. The energy storage density is 0.6 kW.h/m3 ^and 1.4 kW.h/m³ higher, respectively. In addition, increasing the pressure difference in the compression process of the system and rationally distributing the heat transfer ratio of the heat exchanger are conducive to improving the thermodynamic performance of the system. The research results provide a reference for improving the efficiency of compressed CO2 energy storage system.

TK221

国家自然科学基金项目（面上项目，重点项目，重大项目）