Cryocoolers 10 pp 707-716 | Cite as

Optimal Integration of Binary Current Lead and Cryocooler

  • H.M. Chang
  • S.W. Van Sciver
Chapter

Abstract

An optimal integration of a binary current lead and a two-stage cryocooler has been analytically sought to minimize the required refrigerator power. The binary current lead is a series combination of a normal metal conductor at the warmer part and a high Tc superconductor (HTS) at the colder part. The lead is cooled by direct contacts with the first stage of the two-stage cryocooler at the joint and with the second stage at the cold end. No helium boil-off gas is present.

A new and simple analytical method is developed to calculate the cooling loads at the two locations in the binary lead. A mathematical expression for the required power input for the loads is derived by incorporating a model depicting the performance of actual cryocoolers. With a new graphical method, the optimal conditions are found for the cooling temperature at the joint and the dimensions of the two parts to minimize the refrigerator power per unit current.

The results show that there exists an optimal relation between the length and the current density of the metal lead, which is independent of the HTS part or the cryocooler. It is also demonstrated that the current density of the HTS and the joint temperature have unique optimal values respectively to minimize the refrigerator power per unit current, when the length of the HTS part and its critical properties are given. The actual power input to the cryocooler in the optimal conditions is compared with its minimum as a thermodynamic limit, which can be obtained with reversible refrigerators. In addition, a useful dimensionless number is introduced for the optimal cooling of the binary current leads.

Keywords

Thermodynamic Limit Critical Current Density Current Lead Unit Current Cooling Load 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
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Copyright information

© Kluwer Academic Publishers 2002

Authors and Affiliations

  • H.M. Chang
    • 1
  • S.W. Van Sciver
    • 2
  1. 1.Dept. of Mechanical EngineeringHong Ik UniversitySeoulKorea
  2. 2.National High Magnetic Field LabTallahassee

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