非共沸工质与纯工质在ORC系统中的特性比较研究  

Comparative Study on Characteristics of Zeotropic and Pure Working Fluids in Organic Rankine Cycle System

作　　者：王小柳[1] 吴俐俊[1] 张晓君[1] 袁志成[1] 

机构地区：[1]同济大学机械与能源工程学院,上海201804

出　　处：《热能动力工程》2017年第5期37-43,共7页Journal of Engineering for Thermal Energy and Power

基　　金：国家自然科学基金(51574179)

摘　　要：工质的特性是影响ORC(有机朗肯循环)系统性能的重要因素之一。建立了65~100℃低温地热水有机朗肯循环发电系统数学模型,将R245fa分别与R601a和R227ea以不同比例混合作为ORC系统的工质,比较了非共沸混合物和纯物质两类工质对ORC系统循环净功、热效率和火用效率的影响。研究结果表明:无论是纯工质还是非共沸工质,系统的循环净功、热效率和火用效率都随着热源温度的升高而增大。工质在相变过程中是否存在温度滑移,是影响ORC系统性能的重要因素之一。在65~100℃的热源条件下,综合考虑3个评价指标,当R245fa配比为0.1~0.7时,R245fa/R601a混合物的循环净功、热效率和火用效率分别提升0.012~2.48 k W、0.005%~1.15%和0.08%~10.7%;当R245fa配比为0.5~0.9时,R245fa/R227ea混合物的循环净功、热效率和火用效率分别提升0.049~4.25 k W、0.057%~1.75%和0.21%~16.1%。Characteristic of working fluids is one of the most important factors that affect the Organic Rankine Cyclesystem( ORC). A mathematical model for low temperature geothermal water Organic Rankine Cycle power generation system at 65 ℃ ~ 100 ℃ was established. R245fa was mixed respectively with R601a and R227ea in different propor-tions as working fluids in ORC system. The effects of zeotropic mixtures and pure substance on cycle net work,thermal efficiency and exergy efficiency in ORC system were compared. The results showed that for both pure and zeotropic working fluids,the cycle net work,thermal efficiency and exergy efficiency increase with the heat source temperature. During the phase transition process,whether or not there is temperature slip is one of the important factors that affect the performance of ORC system. With three evaluation indexes considered,for the heat source condition of 65 ℃ ~ 100 ℃ and the R245fa ratio of 0. 1 ~ 0. 7,the cycle network,thermal efficiency and exergy efficiency of R245fa/R601a increase by 0. 012 kW ~ 2. 48 kW,0. 005% ~ 1. 15% and 0. 08% ~ 10. 7%,respectively. For the R245fa ratio of 0. 5 ~ 0. 9,the cycle network,thermal efficiency and exergy efficiency of R245fa/R227ea increase by 0. 049 kW ~ 4. 25 kW,0. 057% ~ 1. 75% and 0. 21% ~ 16. 1%,respectively.

关 键 词：非共沸工质 纯工质 有机朗肯循环 特性比较 

分 类 号：TK47[动力工程及工程热物理—动力机械及工程]