A commercial pulse tube cryocooler with 200 W refrigeration at 80 K

An electrically driven pulse tube cryocooler that produces 200 W of refrigeration at 80 K is now available from Praxair Inc. The unit can be used to provide refrigeration by de-superheating, liquefying and/or subcooling a stream of nitrogen. The electroacoustic transducer used in the cryocooler is a dual opposed piston, moving magnet design from CFIC Inc. The pistons maintain a clearance seal and thus no lubricants are needed. The electrical power consumed by the driver at full refrigeration load is 4.3 kW giving an overall efficiency of 13% of Carnot. The cryocooler as a whole is designed for high reliability and no routine maintenance. The paper will describe the rapid evolution of the cryocooler from a laboratory-based prototype to a commercial offering. Experimental results from refrigeration performance tests and load curves will be described. A brief overview of continuing efforts to improve performance, efficiency and envelope size will also be provided.