Speaker
Description
Magnetic refrigeration and hydrogen liquefaction based on the active magnetic regenerator cycle require the applied field to be ramped up and down repeatedly. In a superconducting drive coil the resulting AC loss is dissipated directly into the cryogenic environment, so it competes with the useful cooling power of the device and sets a practical ceiling on the achievable cycle rate. Reducing this loss is therefore a prerequisite for compact, fast-cycling systems.
We report a numerical evaluation of the AC loss of REBCO coils wound from micro-filamentary coated conductor. The conductor is assumed to be processed by a fabrication route proposed by the present authors, which subdivides the tape into narrow filaments while maintaining a high inter-filament resistance. Coils operating at 20 K and generating up to 5 T are analysed using a three-dimensional electromagnetic model that resolves the individual filaments together with the resistive paths between them, so that both the hysteretic and the inter-filament coupling contributions to the total loss are obtained.
Calculations are carried out for filament numbers up to N = 100 and for several winding configurations. The dependence of the total loss on these parameters, the relative weight of the two loss mechanisms, and the resulting implications for the thermal load budget of the cryocooler are discussed.
| Submitters Country | Japan |
|---|---|
| Are you a student? | No |
| Author Affiliations & Email Addresses | I confirm that valid email addresses and affiliations have been added for all co-authors. |
| Co-Author Affirmation | By clicking here, I, the submitting author, affirm that all co-authors know of and concur with the submission of this abstract. |