Comparing superconducting and permanent magnets for magnetic refrigeration

Rasmus Bjørk, Kaspar Kirstein Nielsen, C. R. H. Bahl, Anders Smith, Anders Christian Wulff

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We compare the cost of a high temperature superconducting (SC) tape-based solenoidwith a permanent magnet (PM) Halbach cylinder for magnetic refrigeration.Assuming a five liter active magnetic regenerator volume, the price of each type ofmagnet is determined as a function of aspect ratio of the regenerator and desiredinternal magnetic field. It is shown that to produce a 1 T internal field in theregenerator a permanent magnet of hundreds of kilograms is needed or an area ofsuperconducting tape of tens of square meters. The cost of cooling the SC solenoidis shown to be a small fraction of the cost of the SC tape. Assuming a cost ofthe SC tape of 6000 $/m2 and a price of the permanent magnet of 100 $/kg, thesuperconducting solenoid is shown to be a factor of 0.3-3 times more expensive thanthe permanent magnet, for a desired field from 0.5-1.75 T and the geometrical aspectratio of the regenerator. This factor decreases for increasing field strength, indicatingthat the superconducting solenoid could be suitable for high field, large coolingpower applications. 
Original languageEnglish
Article number056205
JournalA I P Advances
Issue number5
Number of pages6
Publication statusPublished - 2016

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© 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.


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