基于单螺杆膨胀机有机朗肯循环有无回热系统性能分析

有机朗肯循环（ORC）是实现中低温热源发电利用的有效技术,膨胀机是系统热功转换核心部件,其性能表现直接制约系统整体性能。本文设计搭建单螺杆膨胀机回热式有机朗肯循环发电系统,R245fa为系统工质,实验分析恒定冷热源参数下回热式和无回热两类系统和膨胀机主要性能参数的变化规律。实验结果表明：两类系统效率随着膨胀机转矩和转速的增加而增大,膨胀机转矩和转速相同时回热式系统效率较大,当膨胀机转速为1300r/min,回热式系统最大效率为7.20%,比无回热系统效率增加了11.9%;由于回热器利用膨胀机乏汽预热蒸发器入口的有机工质,因此回热式系统相对于无回热式系统的膨胀机入口过热度、等熵效率增加,膨胀比和蒸发器的换热量减小,工质在回热器中的压降是回热式系统膨胀比变小的主要因素。随着膨胀机转矩和转速增加,两类系统蒸发器吸热量和膨胀比增大,膨胀机等熵效率和入口过热度减小。

Performance analysis of regenerative and non-regenerative organic Rankine cycle using single-screw expander

Organic Rankine cycle (ORC) system is an effective way to generate electricity with medium and low temperature heat sources. ORC system with a regenerator was designed and constructed with R245fa as the working fluid in this study. The efficiencies of the two systems and the expander performance were studied under constant cold and heat source. The results showed that the efficiencies of the two systems were higher with increasing expander torque and speed. The regenerative system had a higher efficiency. When the speed of the expander was 1300r/min, the maximum efficiency of the regenerative system was 7.20%, being 11.9% higher than the non-regenerative system. Because heat transfer of exhaust steam from evaporator and high pressure organic working fluid at the entrance of evaporator occurred in regenerator, the isentropic efficiency and superheat of inlet of expansion of regenerative system were higher than the non-regenerative system, but the expansion ratio and heat absorption of evaporator were reduced. With increasing expander torque and speed, the heat absorption and expansion ratio of the two systems were higher, but the isentropic efficiency and inlet superheating of the expander showed opposite tendency.