基于MOSSA算法的混合工质双压ORC系统多目标优化

Multi-objective optimization of mixed working fluid dual-pressure ORC system based on Mossa algorithm

以R141b/R245fa混合工质为研究对象,利用Matlab软件建立混合工质双压有机朗肯循环(ORC)系统数学模型,分析混合工质组分、高压蒸发温度、低压蒸发温度对系统热力、经济、环境性能的影响。采用多目标麻雀搜索(MOSSA)算法对系统热力、经济、环境性能进行多目标优化,并对3种性能的函数关系进行拟合。结果表明:系统热效率与R141b质量分数呈负相关,随高压蒸发温度呈先增大后减小趋势,存在最佳高压蒸发温度使系统热效率达到最大,与低压循环蒸发温度呈正相关;混合工质双压ORC热经济环境三目标优化的Pareto最优解(η_(orc),LEC,ECE)为(0.1343,0.7019元/kWh,11.605 kgCO_(2)eq/kWh),综合性能最优时的运行参数为R245fa质量分数为0.1,高压循环蒸发温度为387.65 K,低压循环蒸发温度为357.83 K,窄点温差为5.02 K,提高系统热力性能和环境性能必然会降低其经济性能。

R141b/R245fa mixed working fluid is used as the research object,the mathematical model of the hybrid working fluid double-pressure organic Rankine cycle(ORC)system is established by Matlab software,the effects of mixed working fluid components,high-pressure evaporation temperature and low-pressure evaporation temperature on the thermal,economic and environmental performance of the system are analyzed,and the multi-objective sparrow search algorithm(MOSSA)algorithm is used to optimize the thermal,economic and environmental performance of the system,and the functional relationship of the three performances is fitted.The results show that the thermal efficiency of the system is negatively correlated with the mass fraction of R141b,and the trend of first increasing and then decreasing with the high-pressure evaporation temperature,and the existence of the optimal high-pressure evaporation temperature maximizes the thermal efficiency of the system,which is positively correlated with the low-pressure circulating evaporation temperature.The Pareto optimal solution(η_(orc),LEC,ECE)for three-objective optimization of hybrid working fluid double-pressure ORC thermal economic environment is(0.1343,0.7019 yuan/kWh,11.605 kgCO_(2)eq/kWh),the operating parameters at the optimal comprehensive performance are R245fa mass fraction of 0.1,the high-pressure circulating evaporation temperature is 387.65 K,the low-pressure circulating evaporation temperature is 357.83 K,and the narrow point temperature difference is 5.02 K.Improving the thermal performance and environmental performance of the system will inevitably reduce its economic performance.