Performance analysis of a rotary active magnetic refrigerator

Jaime Lozano, Kurt Engelbrecht, Christian R.H. Bahl, Kaspar Kirstein Nielsen, Dan Eriksen, Ulrik Lund Olsen, J.R. Barbosa Jr., Anders Smith, A.T. Prata, Nini Pryds

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Performance results for a novel rotary active magnetic regenerator (AMR) and detailed numerical model of it are presented. The experimental device consists of 24 regenerators packed with gadolinium (Gd) spheres rotating inside a four-pole permanent magnet with magnetic field of 1.24T. A parametric study of the temperature span, cooling power, coefficient of performance (COP) and efficiency of the system was carried out over a range of different hot reservoir temperatures, volumetric flow rates and cooling powers. Detailed modeling of the AMR using a 1D model was performed and compared with the experimental results. An overall mapping of the thermal losses of the system was performed, and good agreement between the experimental and numerical results was found when parasitic heat losses were subtracted from the modeling results. The performance of the system was evaluated via the COP, the exergetic-equivalent cooling power (ExQ), and the overall second law efficiency, η2nd. Losses mapping indicated that friction and thermal leakage to the ambient are the most important contributors to the reduction of the system performance. Based on modeling results, improvements on the flow distributor design and reduction of the cold end thermal parasitic losses are expected to enhance the efficiency of the system. For an operating frequency of 1.5Hz, a volumetric flow rate of 400L/h, a hot reservoir temperature of 297.7K, and thermal loads of 200 and 400W, the obtained temperature spans, δTS, were 16.8K and 7.1K, which correspond to COPs of 0.69 and 1.51, respectively. The maximum overall second-law efficiency was 5.6% for a δTS of 12.9K at 500L/h and 400W. © 2013 Elsevier Ltd.
Original languageEnglish
JournalApplied Energy
Volume111
Pages (from-to)669-680
ISSN0306-2619
DOIs
Publication statusPublished - 2013

Keywords

  • Cooling
  • Flow control
  • Flow rate
  • Magnetic refrigeration
  • Meteorology
  • Regenerators
  • Telecommunication links
  • Efficiency

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