Experimental testing and numerical simulation of scroll expander in a small scale organic Rankine cycle system

An Organic Rankine Cycle (ORC) system was built to test the performance of a scroll expander with organic working fluid R123. The output performance of the scroll expander was tested under different conditions with various electric loads and pump capacity. Meanwhile, based on the geometric structure of the scroll expander and using thermodynamic method integrated with force balance analysis, the working process of the scroll expander was simulated. The simulation results were compared with the experimental data. The scroll expander modified from a scroll compressor worked stably in the ORC system. The maximum output power, maximum isentropic efficiency, and maximum rotation speed was 1540 W, 86%, and 2165 r/min respectively in the experiments. The average deviation between the simulation and the experimental results was 18.9%. The numerical model developed in this paper could predict the output performance of the scroll expander and state parameters in expansion chambers.