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Fujita, Akira; Fujieda, Shun; Hasegawa, Yoshihiko; Fukamichi, K.

doi:10.1103/physrevb.67.104416

Cited by 1,045 publications

(654 citation statements)

References 34 publications

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“…In this section the flow in the channels is modeled as being fully developed over the entire length of the regenerator. The regenerator material is assumed to be a layered bed of La(Fe x Si 1-x ) 13 H y compound with properties consistent with those described by Fujita et al (2003).…”

Section: Advanced Regenerator Resultsmentioning

confidence: 99%

A Numerical Model of an Active Magnetic Regenerator Refrigeration System

2005

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Active magnetic regenerator refrigeration (AMRR) systems are an environmentally attractive space cooling and refrigeration alternative that do not use a fluorocarbon working fluid. Two recent developments have made AMRRs appear possible to implement in the near-term. A rotary regenerator bed utilizing practical and affordable permanent magnets has been demonstrated to achieve acceptable COP. Concurrently, families of magnetocaloric material alloys with adjustable Curie temperatures have been developed. Using these materials it is possible to construct a layered regenerator bed that can achieve a high magnetocaloric effect across its entire operating range, resulting in an improved COP.There is currently no tool capable of predicting the performance of a layered AMRR. This project provides a numerical model that predicts the practical limits of these systems for use in space conditioning and refrigeration applications. The model treats the regenerator bed as a one dimensional matrix of magnetic material with a spatial variation in Curie temperature and therefore magnetic properties. The matrix is subjected to a spatially and temporally varying magnetic field and fluid mass flow. The variation of these forcing functions is based on the implementation of a rotating, multiple bed configuration. The numerical model is solved using a fully implicit (in time and space) discretization of the governing energy equations. The nonlinear aspects of the governing equations (e.g., fluid and magnetic property variations) are handled using a relaxation technique.The model is used to optimize AMRR applications by varying model inputs such as matrix material, fluid mass flow rate, working fluid, reservoir temperatures, and the variation of the Curie temperature across the bed. The preliminary model has been verified qualitatively using simple cycle parameters and constant property materials and quantitatively by comparing the results with prior solutions to the regenerator governing equations in the limits of constant properties and no magnetocaloric effect. A second goal of this project is to create a cost estimate for a future project that will design, build, and test a prototype AMRR to be used to verify the numerical model.

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Section: Advanced Regenerator Resultsmentioning

confidence: 99%

A Numerical Model of an Active Magnetic Regenerator Refrigeration System

2005

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“…Systems based on La(Fe,Si) 13 also exhibit significant MCE, enabling them to be considered as potential refrigerants [10]. Most of the materials studied so far show considerable MCE close to their magnetic ordering temperatures, resulting in a single peak in the temperature variation of MCE plots.…”

Section: Introductionmentioning

confidence: 99%

Role of Fe substitution on the anomalous magnetocaloric and magnetoresistance behaviour in Tb(Ni_1−xFe_x)₂compounds

Singh¹,

Суреш²,

Rana³

et al. 2006

J. Phys.: Condens. Matter

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Abstract. We report the magnetic, magnetocaloric and magnetoresistance results obtained in Tb(Ni 1-x Fe x ) 2 compounds with x=0, 0.025 and 0.05. Fe substitution leads to an increase in the ordering temperature from 36 K for x=0 to 124 K for x=0.05. Contrary to a single sharp MCE peak seen in TbNi 2 , the MCE peaks of the Fe substituted compounds are quite broad. We attribute the anomalous MCE behavior to the randomization of the Tb moments brought about by the Fe substitution. Magnetic and magnetoresistance results seem to corroborate this proposition. The present study also shows that the anomalous magnetocaloric and magnetoresistance behavior seen in the present compounds is similar to that of Ho(Ni,Fe) 2 compounds.

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“…15) . Below the Curie temperature T C in the range 200 -260 K, the compound orders ferromagnetically, and above T C an itinerant-electron metamagnetic transition is induced by an external fi eld 16 . Such an itinerant-electron metamagnetic transition originates from a magnetic-fi eld-induced change in the density of states of the 3d electrons at the Fermi level 17 .…”

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confidence: 99%

“…Th ere is no change in the crystal symmetry, but the sample isotropically expands as it transforms from the high-temperature paramagnetic to the lowtemperature ferromagnetic phase. Such a volume change makes the compound highly sensitive to the application of an external hydrostatic pressure; and indeed the eff ect of pressure on the magnetic and magnetocaloric properties has been reported 16,20 . Th e volume change reported for La -Fe -Si is one of the largest for magnetocaloric materials undergoing magnetostructural transitions.…”

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confidence: 99%

Inverse barocaloric effect in the giant magnetocaloric La–Fe–Si–Co compound

et al. 2011

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Application of hydrostatic pressure under adiabatic conditions causes a change in temperature in any substance. This effect is known as the barocaloric effect and the vast majority of materials heat up when adiabatically squeezed, and they cool down when pressure is released (conventional barocaloric effect). There are, however, materials exhibiting an inverse barocaloric effect: they cool when pressure is applied, and they warm when it is released. Materials exhibiting the inverse barocaloric effect are rather uncommon. Here we report an inverse barocaloric effect in the intermetallic compound La-Fe-Co-Si, which is one of the most promising candidates for magnetic refrigeration through its giant magnetocaloric effect. We have found that application of a pressure of only 1 kbar causes a temperature change of about 1.5 K. This value is larger than the magnetocaloric effect in this compound for magnetic fi elds that are available with permanent magnets.

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Itinerant-electron metamagnetic transition and large magnetocaloric effects inLa(FexSi1−x

Cited by 1,045 publications

References 34 publications

A Numerical Model of an Active Magnetic Regenerator Refrigeration System

A Numerical Model of an Active Magnetic Regenerator Refrigeration System

Role of Fe substitution on the anomalous magnetocaloric and magnetoresistance behaviour in Tb(Ni_1−xFe_x)₂compounds

Inverse barocaloric effect in the giant magnetocaloric La–Fe–Si–Co compound

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Itinerant-electron metamagnetic transition and large magnetocaloric effects inLa(FexSi1−x

Cited by 1,045 publications

References 34 publications

A Numerical Model of an Active Magnetic Regenerator Refrigeration System

A Numerical Model of an Active Magnetic Regenerator Refrigeration System

Role of Fe substitution on the anomalous magnetocaloric and magnetoresistance behaviour in Tb(Ni1−xFex)2compounds

Inverse barocaloric effect in the giant magnetocaloric La–Fe–Si–Co compound

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Role of Fe substitution on the anomalous magnetocaloric and magnetoresistance behaviour in Tb(Ni_1−xFe_x)₂compounds