Supercharger, heat pumps, Centrifugal compressor
The on-going development of a compact centrifugal compressor as a first stage or pre-compressor for cold climate operation of heat pumps is described. Positioned in the low pressure vapor portion of the refrigerant loop, this compressor will, on cold days, operate automatically to boost refrigerant pressure, in a manner similar to the way an automotive supercharger pressurizes air. The single stage motor driven centrifugal compressor runs on oil-free bearings. It is being configured to work in concert with a traditional heat pump compressor. The goal of this work is to enable air source heat pumps to efficiently extract heat from even the coldest ambient air without backup heat and without changing refrigerant type or the basic design of the positive displacement style compressors widely used in today’s heat pumps. Doing so will allow air source heat pumps to operate effectively in virtually all major population centers. To date, a first article supercharger has been designed and built, and its performance mapped. Work to integrate it with a commercially available positive displacement (PD) heat pump compressor is underway.