Cold Cycle Dilution and Superfluid Joule-Thomson Refrigerator

Massachusetts Institute Of Technology, Cambridge MA

Investigators

Abstract

A new ultra low temperature refrigerator, the superfluid Joule-Thomson refrigerator (SJTR), will be developed. The SJTR is a single-phase refrigerator that can be used in zero gravity as well as terrestrial environments. It is projected to provide cooling to temperatures of 0.5 Kelvin (K). The SJTR uses a cold (~1 K) superleak-bypassed piston compressor to compress the 3He component of a 3He-4He liquid mixture . In the SJTR cycle, the compressed 3He is discharged by the compressor and passed through counterflow heat exchangers to a superleak bypassed throttle. The 3He component of the mixture cools as it passes through the throttle and the fluid is used to absorb heat from a thermal load. The 3He component is warmed back up to the compressor temperature by passing back through the counterflow heat exchanger. The 3He is then recompressed in the compressor where it continues back through the cycle. The project will include the development of the cold compressor and a demonstration of the superfluid Joule- Thomson concept.