An Investigative Review and Experimental Approach for the Performance Assessment of Small Scale Gifford-McMahon Cryocooler

Abstract

Helium recondensation or liquefaction system is the best platform to liquefy or to condense the helium in many applications viz., Nuclear Magnetic Resonance (NMR), Magnetic Resonance Imaging (MRI) and Superconducting Quantum Interference Devices (SQUIDS). These applications make use of liquid helium as a refrigerator. The large scale liquefaction systems serve as a central facility to provide liquid helium. The above mentioned applications require refilling on a regular basis which is troublesome in case of large scale liquefaction system; one can make use of small scale liquefaction setup based on a cryocooler. An effort has been made to develop a small scale liquefaction system by using two-stage Gifford McMahon cryocooler. This investigative review paper illustrates the liquefaction of helium by using a commercial cryocooler with 1.5 W cooling power at 4.2 K, provided with facility to precooling of incoming gas by using special type of heat exchangers.Impact Factor (JCC): 7.6197 SCOPUS Indexed Journal NAAS Rating: 3.11 either isentropic or isenthalpic. Usually Joule-Thomson expansion results in an isenthalpic expansion and a reciprocating engine or turbine expansion results in an isentropic expansion. Normally the helium gas liquefaction is carried out by the conventional Linde and Claude's processes. In Linde method, air is cooled, compressed and expanded in an alternate manner and the expansion process results in a lowering of temperature each time [3,4].