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Cryogenic cooling system of HTS transformers by natural convection of subcooled liquid nitrogen.

Author(s) : CHANG H. M., CHOI Y. S., SCIVER S. W. van, et al.

Summary

Heat transfer analysis on a newly proposed cryogenic cooling system is performed for HTS transformers to be operated at 63-66 K. In the proposed system, HTS pancake windings are immersed in a liquid nitrogen bath where the liquid is cooled simply by colder copper sheets vertically extended from the cold head of a cryocooler. Liquid nitrogen in the gap between the windings and the copper sheets develops a circulating flow by buoyancy force in the subcooled state. The calculation results show that the warm end of the HTS windings can be maintained at only 2-3 K above the freezing temperature of nitrogen, with acceptable values for the height of HTS windings and the thickness of copper sheets. It is concluded that the cooling by natural convection of subcooled liquid nitrogen can be an excellent option for compactness, efficiency, and reliability of HTS transformers.

Details

  • Original title: Cryogenic cooling system of HTS transformers by natural convection of subcooled liquid nitrogen.
  • Record ID : 2005-0039
  • Languages: English
  • Publication date: 2003/10
  • Source: Source: Cryogenics/Proc. Korea-Jpn. jt. Workshop 2002 appl. Supercond. Cryog., Seoul
    vol. 43; n. 10-11; 589-596; fig.; tabl.; 18 ref.

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