Remote Cooling System Study Based on a Two-Stage Cryocooler with a Helium Circulation Loop

Helium circulation loops enable the separation of the cooling source, e.g. a cryocooler from its cooling interface. Such remote cooling systems need to be adapted to the cooling power of the cryocooler at the respective temperature levels while respecting its performance and possible noise sources such as mechanical or temperature fluctuations. This paper presents the performance results of a remote cooling circuit, which uses three high-effectiveness mesh-based counter-flow heat exchangers. The used two-stage GM cryocooler has a cooling power of 0.4 W at 8.8 K, while the introduction of the helium circulation loop with a Joule-Thomson stage allowed to reach a cooling power of 0.4 W at 4.6 K remote cooling interface. The circulation loop is characterised at pressures of up to 4 bar and below 1.3 bar on the high- and low-pressure sides, respectively. The return flow is brought below atmospheric pressure with the aim to achieve even lower temperature at the cooling interface.