Editing Refrigeration (section)

===Other methods===
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Other methods of refrigeration include the [[air cycle machine]] used in aircraft; the [[vortex tube]] used for spot cooling, when compressed air is available; and [[thermoacoustic refrigeration]] using sound waves in a pressurized gas to drive heat transfer and heat exchange; [[steam jet cooling]] popular in the early 1930s for air conditioning large buildings; thermoelastic cooling using a smart metal alloy stretching and relaxing. Many [[Stirling cycle]] heat engines can be run backwards to act as a refrigerator, and therefore these engines have a niche use in [[cryogenics]]. In addition, there are other types of [[cryocoolers]] such as Gifford-McMahon coolers, Joule-Thomson coolers, [[Pulse tube refrigerator|pulse-tube refrigerators]] and, for temperatures between 2 mK and 500 mK, [[dilution refrigerator]]s.