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Experimental comparison of 3He/4He heat switches at 1K.

Author(s) : WANG X., WANG Y., YING K., LU L., JIANG Z., WU Y., LIU S.

Type of article: IJR article

Summary

In cryogenic systems, gas-gap heat switches (GGHSs) are preferred for simple structure, no moving parts and high reliability, of which helium gas gap heat switches are the most widely applied. This paper compares the per formance of ⁴He/³He GGHSs at an ultra-low temperature of 1 K by installing them on an ⁴He adsorption refrigerator. Performances analysed include response time, the on-state characteristics, switch ratio, and the effect of the adsorption pump temperature on thermal conductance. Experiment results reveal that the 3He GGHS exhibits a 50% shorter response time when switching on, but needs an extra 19 min to switch off compared to the 4He GGHS. Under a certain charging pressure, the on-state conductance of the 3He GGHS is 3.043 mW⋅K-1 and that of the 4He GGHS is 2.674 mW⋅K-1. The switch ratio of ⁴He GGHS with a heating power of 50 μW is 127, while that of 3He GGHS under 1 bar is only 112, even drops to 90 with a heating power of 100 μW. For different charging pressures, the switch ratio of ³He GGHS under 1 bar is higher than that under 0.5 bar (96 with a heating power of 50 μW). Therefore, in practical applications, selection between 4He and 3He GGHSs can be made based on engineering requirements and pump temperature ranges.

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Details

  • Original title: Experimental comparison of 3He/4He heat switches at 1K.
  • Record ID : 30034983
  • Languages: English
  • Subject: Technology
  • Source: International Journal of Refrigeration - Revue Internationale du Froid - vol. 188
  • Publication date: 2026/08
  • DOI: http://dx.doi.org/10.1016/j.ijrefrig.2026.106959

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