ROVACS: A New Rotary-Vane Air-Cycle Air-Conditioning and Refrigeration System

The ROVAC unit is a rotary vane combination compressor-expander-circulator, which is the key element in a new air-cycle refrigeration system. Results of an analytical and experimental feasibility study of the system are reported here. The objective of the study was to develop and verify a mathematical model of the system, including heat-exchanger pressure loss and mechanical friction. A parametric study was made to determine the geometry for a unit capable of cooling a passenger car, and a conservatively designed prototype was built and tested. The prototype system produced a cooling capacity of 5400 Btu/h and generally verified the accuracy of the mathematical model.

The coefficient of performance of the prototype system is somewhat lower than that of a typical vapor-cycle system.* However, the ROVAC system is much simpler and will most likely be cheaper to build. The system response time is very short (approximately 10 s), so immediate passenger comfort could be provided in an automotive application.

Although a passenger car application is used as an example in the paper, the mathematical model could be used for computer-aided design of any ROVAC system.