基于多目标函数的亚临界有机朗肯循环的参数优化和性能分析  

Parametric optimization and performance analysis of subcritical organic Rankine cycle based on multi-objective function

作　　者：吴双应[1,2] 易甜甜 肖兰[1,2] 

机构地区：[1]重庆大学低品位能源利用技术及系统教育部重点实验室 [2]重庆大学动力工程学院,重庆400044

出　　处：《化工学报》2014年第10期4078-4085,共8页CIESC Journal

基　　金：国家重点基础研究发展计划项目(2011CB710701)~~

摘　　要：以系统净输出功率Wnet、热源流体进出口降ΔEg、系统总不可逆损失I和系统总投资成本C2013构建多目标优化模型,采用线性加权评价函数法对该模型进行求解,以R600a、R245fa、R601a、Pentane 4种纯工质以及R600a/R601a、R245fa/R601a、R245fa/Pentane和R600a/R245fa 4种非共沸混合工质为例,对亚临界有机朗肯循环(ORC)的蒸发温度Te和冷凝温度Tc进行优化。研究结果表明:采用单目标有时得不到最优值,而采用多目标均能得到最优值,且多目标优化可以较好地协调各性能指标间的关系,使所要求的各项指标均能达到较优,因此多目标优化比单目标优化更加合理;存在最优蒸发温度Te,opt和最优冷凝温度Tc,opt使多目标函数F(X)最小,同时,Te,opt、Tc,opt随工质不同而不同;在Te,opt或Tc,opt下,对比纯工质和混合工质的不同单目标函数值和F(X)值时,混合工质并不总是优于纯工质。A multi-objective optimization model is built, which incorporates the net power outputWnet, exergy drop of exhaust fluid from inlet to outletΔEg, total exergy destruction rateI, and total costC2013 of system into one function, and solved with the method of linear weighted evaluation function. Taking single working fluids R600a, R245fa, R601a and Pentane, and non-azeotropic mixed working fluids R600a/R601a, R245fa/R601a, R245fa/Pentane, and R600a/R245fa as examples, the evaporation temperatureTe and condensation temperatureTc of subcritical organic Rankie cycle （ORC） are optimized. The results reveal that sometimes the optimal point can not be obtained using single-objective function, while it always can with multi-objective function. Moreover, the multi-objective optimization of ORC seems superior to single-objective optimization, because the multi-objective optimization coordinates the relationships among various performance indicators, which makes each indicator reach the optimal point as possible. Additionally, there exists optimal evaporation temperatureTe,opt and condensation temperature Tc,opt minimizing the multi-objectivefunctionF（X） values, but they vary with working fluids. Formulti-objective optimization atTe,opt andTc,opt, the comparisons of different single-objective function values andF（X） between non-zeotropic mixed working fluids and single working fluids show that the ORC performance of mixed working fluids is not always better than that of single working fluids.

关 键 词：有机朗肯循环 纯工质 混合工质 多目标优化 经济 热力学 

分 类 号：TK123[动力工程及工程热物理—工程热物理]