Over-Reexpansion as a Means of Compressor Capacity Modulation

The purpose of this paper is to introduce the development of a unique compressor capacity modulation concept which utilizes reexpansion volume as a means of capacity reduction in hermetic air conditioning and refrigeration system. While there are various methods of compressor capacity modulation in use, each particular method is limited in its application or appeal for different reasons such as cost, vibration,performance, reliability or limited compressor range because of high operating temperature. This paper compares this over-reexpansion method with other common methods, and presents its thermodynamic and operating performance characteristics. Then, actual performance data obtained from prototype hardware are compared with actual data of other capacity modulation methods. The comparisons show that this over-reexpansion concept offers unique advantages including a wider compressor application range.