Abstract:

In order to improve the impact of fluctuations in new energy generation on the power grid, this paper proposes an integrated thermal system called the photothermal coupled transcritical compressed carbon dioxide energy storage (TC-CCES) cycle. The dynamic mathematical models of TC-CCES system and photothermal system were established based on the energy and mass balance relationship, and the dynamic response curves of key parameters of TC-CCES system in energy storage and release stage were obtained. The research results show that the energy storage density of the system reaches 28.43 kW/m³, the energy storage efficiency and cycle efficiency are 58.01% and 60.85% respectively, and the maximum error of the dynamic mathematical model is less than 5%. In addition, changes in direct solar radiation cause the system heat source temperature to change, and the system load is very sensitive to changes in heat source temperature. The heat source temperature increases by 2.29%, and the heat exchanger load increases by 3.36%. In a typical day of four seasons in a certain area, the unit load in winter is 23.9% lower than that in autumn. The dynamic mathematical model presented in this paper can be used to analyze the dynamic characteristics of solar power generation, and lays a theoretical foundation for the design of the control system.

Key words: photothermal, T-CO₂ energy storage cycle, model, dynamic characteristic, modeling and simulation

摘要：

为了改善新能源发电波动对电网的影响，提出了一种光热-跨临界压缩二氧化碳储能（transcritical compressed carbon dioxide energy storage，TC-CCES）循环集成热力系统，采用模块化机理建模方法，基于能质平衡关系分别建立TC-CCES系统与光热系统的动态数学模型，获取TC-CCES系统在储释能阶段关键参数的动态响应曲线。研究结果表明，系统的储能密度达到28.43 kW/m³，储能效率与循环效率分别为58.01%和60.85%，动态数学模型的最大误差均小于5%。此外，太阳直射辐射变化促使系统热源温度变化，而系统负荷对热源温度变化非常敏感，热源温度升高2.29%，换热器负荷升高3.36%，而且在某地区四季典型日冬季比秋季机组负荷低了23.9%。提出的动态数学模型可用于分析太阳能发电的动态特性，可为控制系统的设计提供理论参考。

关键词: 光热, T-CO₂储能循环, 模型, 动态特性, 建模仿真