Ames Laboratory; Materials Science and Engineering
Materials Science and Engineering, Ames Laboratory
Energy Conversion and Management
We report operation of a device designed specifically for rapid experimental evaluation of performance of magnetocaloric materials in different magnetic fields using a compact active magnetic regenerator bed with a total volume of approximately 5 mL. Other features of the system include digital control of the rotating-permanent-magnet field source and custom dual-opposed syringe pump that enable precise tuning and coupling of the flow profile and the magnetic field profile. Performance of the device is demonstrated for flow volumes between 1 and 4 mL (utilization from 0.48 to 1.9), maximum magnetic fields of 1.13 and 1.45 T, and applied cooling powers from 0 to 20 W at frequencies from 0.5 to 4 Hz. A regenerator comprised of 25 g of 200 µm spherical Gd powder reached temperature spans of 19.3 K under no applied cooling load and 2.6 K under the maximum applied cooling load of 20 W. The device also achieves a very high specific exergetic cooling power of 73 W L−1 T−1. Results obtained at two different maximum magnetic fields in the same device suggest a powerful new scaling for regenerator performance: the exergetic power quotient. The exergetic power quotient shows a simple scaling of device cooling performance with the amount of active material and the magnetic field strength. This suggests results from a small device correlate to expected performance of a larger regenerator, making the exergetic power quotient a well-suited parameter for evaluating functionality of active magnetic regenerators employing new magnetocaloric materials.
DOE Contract Number(s)
Iowa State University Digital Repository, Ames IA (United States)
Available for download on Wednesday, September 23, 2020