Editing Cryocooler (section)

{{Short description|Refrigeration system that cools to below 120 K}}
A '''cryocooler''' is a refrigerator designed to reach [[cryogenic]] temperatures (below 120 K, -153 °C, -243.4 °F). The term is most often used for smaller systems, typically table-top size, with input powers less than about 20&nbsp;kW. Some can have input powers as low as 2&ndash;3 W. Large systems, such as those used for cooling the superconducting magnets in particle accelerators are more often called cryogenic refrigerators. Their input powers can be as high as 1 MW. In most cases cryocoolers use a cryogenic fluid as the working substance and employ moving parts to cycle the fluid around a thermodynamic cycle. The fluid is typically compressed at room temperature, precooled in a heat exchanger, then expanded at some low temperature. The returning low-pressure fluid passes through the heat exchanger to precool the high-pressure fluid before entering the compressor intake. The cycle is then repeated.
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