中文摘要：

建立有机朗肯循环热力学模型和蒸发器传热模型;基于工质的实验经验状态方程,利用REFPROP 8.0软件获得非共沸工质物性;以获得最佳的凝汽器温度匹配为原则选择工质。采用种温度的地热能,在给定的蒸发器和凝汽器夹点温差下,分析了采用组分比例为0.64：0.36的R600a/R601非共沸工质的有机朗肯循环发电系统的特性,并与R601纯工质发电循环进行了比较。结果表明：以对外输出功为目标函数的利用地热的中低温有机朗肯循环发电系统中不宜加入回热器;对于蒸发器热源进出口温差较小的工况,如热源来自水蒸气凝结放热,采用混合工质的循环的性能不如纯工质的;有机朗肯循环采用混合工质时其最大对外输出功要高于纯工质的,且热源温度越低时,这种优势越明显。

英文摘要：

Thermodynamic model of organic Rankine cycle（ORC） and heat transfer model for evaporator were developed,and thermal properties for mixture working fluid were obtained by REFPROP 8.0 on the basis of the empirical equations of state.The selection principle for working fluids was based on the matching between working fluid and cooling water in the condenser.Geothermal energy in three heat source temperatures was simulated,and a zeotropic mixture,R600a/R601 with mole fraction 0.64/0.36,was used as the working fluid of ORC for power generation with the given pinch temperature for the evaporator and condenser.Its performance was analyzed and compared with that of pure working fluid,R601.The analytical results show that it is not suitable to introduce the internal heat exchanger（IHX） to the ORC system using medium or low temperature geothermal energy as heat source with work output as objective function.ORC system with pure working fluid has a better performance than that with mixture under the condition that temperature difference between inlet and outlet of heat source is small（i.e.using latent heat of steam as heat source）.The maximum work output of the ORC system using mixture as working fluid is much larger than that using pure working fluid.And when the inlet temperature of heat source is lower,the advantage is greater.