Device and method for cooling or liquefying fluid

There is disclosed a device for refrigerating or liquefying a fluid, such as natural gas or hydrogen, comprising a circuit (3) for the fluid to be cooled and having an upstream end connected to a source (2) of gaseous fluid and a downstream end (23) connected to a means for collecting the cooled or liquefied fluid, the device (1) comprising a heat exchanger assembly (6, 10), the invention relates to a device (1) for cooling a fluid to be cooled, comprising a circuit (3) of fluid to be cooled, a heat exchanger assembly (6, 10) in heat exchange with the circuit (3) of fluid to be cooled, the device (1) comprising a refrigerator (20) in heat exchange with at least a portion of the heat exchanger assembly (6, 10), the refrigerator (20) being of the type having a cycle for refrigerating a cycle gas containing at least one of helium, hydrogen, nitrogen or neon; the refrigerator (20) comprises, arranged in series in the circulation circuit (14), means (15) for compressing the circulation gas, at least one means (7,