Introduction of the Revolving Vane Expander

Expanders are becoming increasingly important as refrigeration systems that use carbon dioxide gain popularity. This paper discusses the revolving vane expander, which is a highly efficient, new type of rotary expander. Although the design is similar to that of a rolling piston machine, its design eliminates the friction power losses at all rubbing surfaces, except for at the vane side and the shaft bearings. In this paper, the expander design and its working principles are introduced. A mathematical model is also presented that has been used to investigate the operating characteristics of the expander. The theoretical results confirm that the only significant frictional losses left are at the shaft bearing and that a mechanical efficiency of 94.2% can be obtained.