Recent Advances in Gifford-McMahon Cryocoolers

Abstract

Cryocoolers are devices which produce the required refrigeration at a specific low temperature, and they can replace the normal cryogenic fluids. Cryogenic fluids give refrigeration only at a specific temperature whereas cryocooler can produce refrigeration at varying low temperatures. There are many types of cryocoolers like Pulse tube, Stirling, Joule-Thomson, Gifford-McMahon (GM) etc. Many advances have occurred over the years in these cryocoolers. For obtaining very low temperatures along with large cooling powers GM and Pulse tube cryocoolers are found to be better among the others. Hence, this article focuses the advances in GM cryocoolers. This article discusses the working of GM cryocooler, importance of regenerator material and how one can use special regenerator materials to reach very low temperatures. Further, the advances in these cryocoolers such as the use of Labyrinth finish regenerators to obtain higher cooling powers etc. are also discussed. It is presumed that the reader obtains a basic understanding of the GM cryocooler, latest developments and the possible future areas for research from this article.

Gifford McMahon Refrigerating Cycle for Liquefying Small Amounts of Hydrogen: Analysis of the Performances

“…Finally, it is observed that the amount of gas that remains in the hot chamber A (after the exhaust valve is closed), which recirculates in the next cycle and which mixes with the gas coming from the compressor, is always negligible. In fact, it represents about 0.8% of the total gas that completes the cycle (see Table 1) Through this analysis Theoretically and experimentally, we have found some conclusions that are congruent with other experimental works [15][16][17][18]: indeed, the regenerator is the most critical part of the machine.…”