串联双级蒸发有机朗肯循环系统的多目标优化及工质优选

Multi-objective optimization and working fluids selection of two-stage evaporation series organic Rankine cycle system

为了探究串联双级蒸发有机朗肯循环系统在特定工况下的最佳混合工质,选取了3组不同特性的混合工质,即R21/R113、R1234ze/R141b和R227ea/R245fa,引入热力学性能指标、经济指标和环境指标,利用非支配排序遗传算法进行多目标优化.通过求解Pareto边界,采用3种决策方法对每组工质流体进行最优解的选择,根据偏移量选取最优决策方法.结果表明:在热源温度为150℃、冷源温度为15℃的工况下,混合工质R1234ze/R141b最优解的[火用]效率相对较高,平准化度电成本(levelized cost of energy, LCOE)和当量二氧化碳排放量(equivalent carbon emission, ECE)相对也较低,热源温度也适配,为该工况下较为合适的混合工质.

To explore the best mixing working fluid of the two-stage evaporation series organic Rankine cycle system under specific working conditions,three groups of mixing working fluids with different characteristics of R21/R113,R1234ze/R141b and R227ea/R245fa were selected.According to thermodynamic performance,economic index and environmental index,the non-dominated sorting genetic algorithm was used for the multi-objective optimization.By solving Pareto boundary,three decision methods were used to select the optimal solution for each working fluid group.The optimal decision method was selected according to the offset.The results show that when the heat source temperature is 150℃with the cold source temperature of 15℃,the exergy efficiency of the optimal solution of the mixing working fluid of R1234ze/R141b is relatively high with relatively low levelized cost of energy(LCOE)and equivalent carbon emission(ECE),and the heat source temperature is also suitable,which illuminates that R1234ze/R141b is relatively suitable mixing working fluid in this working condition.