Performance Simulation of a Twin-screw Expander Using R513A as Working Fluid in Organic Rankine Cycle System

The organic Rankine cycle (ORC) system is an efficient technology to make energy recovery from low grade thermal sources. The performance of expander has a great influence on the efficiency of the ORC system. In this paper, a thermodynamic model of working process in twin-screw expander is established, in which suction pressure loss, leakage and heat transfer are taken into account. Two working fluids, R134a and R513A, are used as working fluids. Suction pressure loss, mass flow rate, output power, filling factor and isentropic efficiency are simulated and p-V diagrams are presented. The results show that R513A performs well in twinscrew expander as a low global warming potential (GWP) alternative refrigerant to R134a.