一种新型的跨临界CO2储能系统
A Novel Transcritical CO2 Energy Storage System

为了解决我国风电并网时电力不稳定等问题,实现规模储能,针对目前压缩空气储能(CAES)系统存在的问题,提出了一种新型的跨临界CO2储能系统概念。系统储能介质CO2以液态形式进行储存,以热能和冷能为能量存储主要形式,实现风电的储能和释能过程。对该系统进行了热力学分析和多目标优化,结果表明:在合适的储能压力下,系统储能效率和储能密度均随着释能压力的增大先增大后减小,分别存在最佳释能压力;随着储能压力升高,系统储能效率不断降低,储能密度却不断增加;减小蓄冷器和中间换热器换热温差是提高系统储能效率的关键;通过对储能系统进行多目标优化,最优解对应的系统储能效率为50’4％,储能密度为21’7 kW？h/m3。跨临界CO2储能系统具有储能密度较高、绿色高效、不受地理条件限制等优点,在风电的规模存储中具备很好的应用前景。
To ensure grid frequency and power stability and realize bulk energy storage, a novel transcritical CO2 energy storage system was proposed in view of the defects in the existing compressed air energy storage systems. The concept is based on taking liquid CO2 as the storage media, thermal energy and cold energy as the main storage forms, so as to realize charging and discharging processes for wind power. Thermodynamic analysis and multi？？objective optimization were performed and results showed that both round？？trip efficiency and energy density increase firstly and then decline with the increase of discharging pressure at suitable charging pressure, which means that there exists an optimal discharging pressure. As charging pressure increases, round？？trip efficiency declines while energy density increases. The key approach to improve the round？？trip efficiency is to decrease the heat transfer temperature differences of cool storage unit, intercooler and reheater. The optimum round？？trip efficiency and energy density are 50.4％ and 21.7 kW？h/m3, respectively. The transcritical CO2 energy storage system has advantages such as high energy density, high？？efficiency and environment friendly, no geographical restriction, showing a promising potential for storing wind power in large scale