| 摘要 |
2149130 9411684 PCTABS00032 A system for providing a cold environment which has a number of cooling stages (10, 10A, 16) with variable displacement volumes (1, 1A, 2) into which input fluid from a compressor (30) flows in an input channel (23) to and from the displacement volumes (1, 1A, 2) and output fluid flows in an output fluid channel (24) to the compressor (30). Volume changers vary the volumes of the displacement volumes (1, 1A, 2) and the input fluid flowing to a first set of displacement volumes is pre-cooled by regenerative heat exchange and counterflow heat exchange and input fluid flowing to the final displacement volume is pre-cooled primarily by counterflow heat exchange. The volume changer at at least one of the stages is thermally decoupled from the input (23) and output (24) channels.
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