Development and Testing of a Rotary-Vane Two-Phase Refrigerating Expander

Rotary-vane positive displacement machines have played an important role for many years in refrigeration and air compression applications because of their inherent simplicity and reliability. This paper details the development and testing of a rotary-vane two-phase expander for the purpose of work recovery in an air-cooled chiller. The paper describes the methodology used to design an expander for two-phase flow from a single-phase compressor and an air-motor. Input from detailed analytical models developed by the authors are used to improve the expander design with respect to internal leakage losses and friction. Controls and performance testing are also presented. Directions for future research are highlighted.