A novel method to hit the limit temperature of Stirling-type cryocooler
Journal of Applied Physics, 2018, 123(6): 063901.
The Stirling-type cryocooler with its compact size and high efficiency is always expected to obtain its temperature limit of below 3K. However, the pressure drop losses caused by high-frequency oscillation create large obstacles for this objective. This paper reports a novel thermal-driven Stirling-type cryocooler to obtain the lowest temperature of a Stirling-type cryocooler. The advantages of a thermal-driven cryocooler (Vuilleumier cryocooler) and pulse tube cryocooler are combined with a new type of cryocooler, called the Vuilleumier gas-coupling pulse tube hybrid cryocooler (VM-PT). A prototype of the VM-PT was recently developed and optimized in our laboratory. By using helium-4 as the working gas and magnetic regenerative materials (HoCu2 and Er3Ni), the lowest temperature of 2.5K was obtained, which can be regarded as an important breakthrough for the Stirling-type cryocooler to achieve its limit temperature of below 3K. It can supply > 30mW cooling power at 4.2K and > 500mW cooling power at 20K simultaneously. Theoretically, it is feasible to use this VM-PT for cooling the superconducting devices in space applications. Published by AIP Publishing.