Special cycles
Helium liquefaction and medium and high energy consumption helium refrigeration.

A cycle capable of absorbing high powers (e.g. over 1 kW at 4.5 K) must, above all, be efficient. To achieve this, it is necessary, if possible, to expand with external work absolutely all the flow that has been compressed. The energy extracted by the expansion machines should be recovered, but this is not currently the case. The Brayton pre-cooling stages also need to be expanded at optimally staggered temperatures. The number of expansion stages also needs to be optimized. Considerations specific to the plant to be cooled must also be taken into account (temperature requirements...