耦合有机朗肯循环的液化空气储能系统优化

Optimization of Liquefied Air Energy Storage System Coupled with Organic Rankine Cycle

储能是解决风能和太阳能等可再生能源发电间歇性和不稳定性的重要技术途径。针对常规液化空气储能系统循环效率较低的问题,引入有机朗肯循环以利用空气液化阶段产生的压缩热。构建耦合有机朗肯循环的液化空气储能系统,以系统循环效率和空气释能发电阶段㶲效率为目标函数,以压缩机组出口压力、低温泵出口压力、冷箱窄点温差和换热器效能为决策变量,运用非劣分类遗传算法NSGA-Ⅱ进行多目标优化。绘制Pareto最优前沿曲线,采用TOPSIS优选法,得到贴近度最大的系统最优设计方案,与之对应的系统循环效率为62.75%。

Energy storage is an important technical route to solve the intermittence and instability issue of renewable energy generation,such as wind energy and solar energy.Hence in this paper,regarding the low cycle efficiency of conventional liquefied air energy storage system,the organic Rankine cycle is introduced to make use of the compressed heat generated during the liquefaction stage.To construct the liquefied air energy storage model coupled with organic Rankine cycle,the system cycle efficiency and the exergy efficiency in the air energy release and generation stage are set as objective functions.The outlet pressure of compressor unit,the outlet pressure of cryopump,the narrow temperature difference of cold box and the efficiency of heat exchanger are taken as decision variables respectively.And the non-inferior classification genetic algorithm NSGA-II is used for multi-objective optimization.The Pareto optimal frontier curve is then depicted and by virtue of the TOPSIS optimization method,the optimal system design scheme is obtained with the nearest approximation degree in which the corresponding system cycle efficiency is 62.75%.