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. © 2019, Chemical Industry Press. All right reserved.