Experimental evaluation of a thermal interface and a cold circulator used in remote cooling loop driven by a cryocooler

Due to helium's limited accessibility and non-renewable nature, superconducting systems need more sustainable alternatives to cryogenic plants, which feature elevated helium losses. Cryogenic systems based on commercially available cryocoolers are seen as a promising solution. In this paper, a remote cooling loop driven by a cryocooler and cold circulator is introduced, and an experimental study of the heat exchanger serving as the cryocooler-to-gas thermal interface is presented. This thermal interface is intended for integration into a remote cooling system, which is designed to intercept the 300 W heat load from 3 kA hybrid current leads. The heat exchanger successfully maintained a gas outlet temperature below 50 K under 300 W. A mathematical model is developed to forecast both the gas outlet temperatures and the cooling capacity of the heat exchanger for a given geometry, and validation is conducted using experimental data. Furthermore, an experimental verification of the isentropic efficiency of the selected cold circulator is included. Finally, an estimation of the mass flow within the hydraulic system is presented and compared with the measured results.