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Patents & Resources
Patents & Publications
Selected publications, patents and resources in magnetic refrigeration, cryogenic liquefaction and cryocooling.
Selected Publications
Performance investigation of a high-field active magnetic regenerator
Reed Teyber et al.; co-author John Barclay. Reports a 100 K temperature span and describes it as the largest reported in the literature at that time.
Open paper →Propane liquefaction with an active magnetic regenerative liquefier
Open paper →Methane liquefaction with an active magnetic regenerative refrigerator
Corey Archipley et al. reports the first successful liquefaction of pure methane with an active magnetic regenerative refrigerator after cooling with four layers of magnetic refrigerants to span from 295 K to 135 K.
Open paper →Can process intensification of liquefaction technology for LNG and LH₂ accelerate adoption for transportation use?
J. A. Barclay and C. C. Archipley. Open-access paper discussing process-intensification concepts for LNG and liquid-hydrogen systems.
Open paper →Selected patents
From active magnetic regeneration to liquefaction systems.
US4332135A
Active magnetic regenerator
John A. Barclay and William A. Steyert. Foundational 1982 patent describing active magnetic regeneration over relatively large temperature ranges.
View patent →US4408463A
Wheel-type magnetic refrigerator
John A. Barclay. Historical magnetic-refrigeration patent using a wheel-type configuration.
View patent →US4507927A
Low-temperature magnetic refrigerator
John A. Barclay. Historical patent addressing magnetic refrigeration in the 4 K to 20 K range.
View patent →US5182914A
Rotary dipole active magnetic regenerative refrigerator
Selected historical patent in active magnetic regenerative refrigeration.
View patent →US6467274B2
Apparatus and methods for cooling and liquefying a fluid using magnetic refrigeration
John A. Barclay and Thomas C. Brook. Patent directed to cooling and liquefaction using magnetic refrigeration.
View patent →US10443928B2
Active magnetic regenerative liquefier using process-gas precooling
Selected liquefaction patent listing Emerald Energy NW and Battelle Memorial Institute as assignees.
View patent →US11555652B2
Active magnetic regenerative processes employing hydrogen as heat-transfer fluid and process fluid
Selected hydrogen-liquefaction patent.
View patent →What is magnetic refrigeration—and why use it?
Cooling with the magnetocaloric effect.
Magnetic refrigeration uses the magnetocaloric effect: certain magnetic materials change temperature as a magnetic field is applied and removed. In an active magnetic regenerator, that effect is coupled with regenerative heat transfer to move heat across a temperature span and, in suitable configurations, to liquefy gases.
Why use it? In the right system, magnetic regeneration can provide efficient cryogenic cooling and liquefaction while reducing reliance on conventional gas-compression refrigeration. Whether it is the right choice depends on the application, operating range and surrounding system. That is where experience—and the numbers—matter.
Industry context
Why cryogenic cooling and liquefaction matter.
Independent sources provide context for the technical and market problems surrounding cryogenic cooling and liquefaction.
Cold Rush
Industry context on scaling cryogenic cooling for quantum computing, helium-3 constraints and alternative approaches including magnetic cooling.
Open source →The Pursuit of Liquid Hydrogen
PNNL feature describing magnetocaloric hydrogen-liquefaction work involving PNNL, EENW and Ames Laboratory.
Open source →Small Business–National Laboratory Collaboration
DOE announcement describing a PNNL collaboration with EENW on a rotary magnetic-wheel seal test apparatus.
Open source →Questions about the work?