4-kW有机朗肯循环系统运行特性实验研究

Experimental investigation on the operating characteristics of a 4-kW scale organic Rankine cycle system

针对分布式发电系统的多工况运行需求,测试了采用R123工质的4.0 kW级有机朗肯循环实验机组在150℃热源条件下,基于工质流量和膨胀机转速控制的多工况运行特性和输出性能。结果表明:机组在膨胀机转速1 000~1 200 r/min性能最佳,提高工质流量可明显改善机组性能;膨胀机输出功和净功效率随工质流量变化趋势相反,在大流量下获得最大输出功3.7 kW,在小流量下取得最大热效率6.41%。涡旋膨胀机内容积比相对较小,机组在测试工况下均运行于欠膨胀状态,其等熵效率在50.0%~60.0%,随工质流量和膨胀机转速的增大而增大。

The distributed energy and power system requires the organic Rankine cycle operate under various conditions. A 4-kW organic Rankine cycle prototype based on a scroll expander and R123 working fluid is tested at the heat source temperature of 150.0 ℃. Results show that the prototype can achieve optimum performance when the expander rotating speed is within the range of 1 000 to 1 200 r/min. The performance could be improved by increasing the working fluid mass flow rate. The shaft power and thermal efficiency have the opposite varying trend with the working fluid mass flow rate. The maximum shaft power of 3.7 kW is obtained at the high mass flow rate of 900 kg/h while the highest thermal efficiency of 6.41% is achieved at the low mass flow rate of 600 kg/h. The working fluid is under-expanded in the expander due to the relatively small build-in volume ratio of the scroll expander. The isentropic efficiency of the expander is from 50.0% to 60.0%. The increase in the mass flow rate and the expander rotating speed can generally improve the expander isentropic efficiency.