Magnetic refrigeration: Single and multimaterial active magnetic regenerator experiments

Richard, Marc-André; Rowe, Andrew; Chahine, Richard

doi:10.1063/1.1643200

Cited by 123 publications

(70 citation statements)

References 8 publications

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“…However, sintered mixtures of compounds are not well suited because they behave as a material with a single T C [5]. Instead of that, the design of specific composites [6][7][8] can lead to an enlargement of the MCE temperature span and an almost constant ΔS M (T) curve. The efficiency of the magnetic material in terms of the energy transfer between the cold (T cold ) and hot (T hot ) reservoirs, is quantified by its refrigerant capacity, RC, an important figure of merit that characterizes the magnetocaloric material [9,10]:…”

mentioning

confidence: 99%

Enhanced refrigerant capacity and magnetic entropy flattening using a two-amorphous FeZrB(Cu) composite

Álvarez

Llamazares

Gorría

et al. 2011

Applied Physics Letters

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The temperature dependence of the isothermal magnetic entropy change, ΔS M , and the The ideal Ericsson cycle (two isothermal and two isomagnetic field processes) is optimal for RT applications [2]. Its maximum efficiency is reached when the MCE exhibits a constant temperature dependence of the isothermal magnetic entropy change, ΔS M (T), within the operating temperature range [3]. This condition is difficult to be accomplished by a single material, but a composite made of two ferromagnetic materials may fulfill it provided that the difference between their Curie points, T C , is customized [4]. However, sintered mixtures of compounds are not well suited because they behave as a material with a single T C [5]. Instead of that, the design of specific composites [6][7][8] can lead to an enlargement of the MCE temperature span and an almost constant ΔS M (T) curve. The efficiency of the magnetic material in terms of the energy transfer between the cold (T cold ) and hot (T hot ) reservoirs, is quantified by its refrigerant capacity, RC, an important figure of merit that characterizes the magnetocaloric material [9,10]:where T cold and T hot are commonly selected as the temperatures corresponding to the full width at half maximum of ΔS M (T). In order to attain large RC values, a large magnetic entropy change over a wide temperature range is desirable. However, it has been shown that although the maximum value of ΔS M decreases, a large broadening of the ΔS M (T)curves can overcompensate such decrease, giving rise to a significant RC enhancement [7,10]. In turn, numerical calculations and their proof-of-principle in practical systemsshow that the design and practical realization of multiphase or composite magneto-3 caloric materials with optimized RC and ΔS M (T) curves is not a simple task [4][5][6]. For a two-phase composite the magnetic field variation of the RC is complex, and depends on several factors such as ΔT C and the shape, width and peak value of ΔS M (T) curve of the two constituents [6].In this letter we report on the MCE in a two-ribbon composite showing a larger RC with respect to that of each individual ribbon and a flattened ΔS M (T) curve. The composite is formed by two Fe-rich FeZrB(Cu) amorphous ribbons. These alloys, which were extensively studied due to their re-entrant spin-glass fig. 3). This RC enhancement is a consequence of the increase in δT FWHM . Nevertheless, a compromise between the value of the δT FWHM and the potential lost of efficiency of the machine (due to an increase of cycles in the heat exchange medium) is needed. In turns, the ΔS comp (T) curves under low magnetic field changes (μ o ∆H < 0.4 T) exhibit a double-peak profile [see inset of Fig. 2(a)], and the δT FWHM cannot be properly defined. 5Both, the enhancement of RC comp and the flattening observed in the ΔS comp curve stimulated us to measure the M(H) curves for the two-ribbon composite. This is important in order to assess whether the shape of M(H) curves is in some extend affected by dipolar interactions between ...

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confidence: 99%

Enhanced refrigerant capacity and magnetic entropy flattening using a two-amorphous FeZrB(Cu) composite

Álvarez

Llamazares

Gorría

et al. 2011

Applied Physics Letters

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“…[5][6][7][8] Recently, nanotechnology has enriched the quest for advance magnetocaloric materials utilizing nanocomposition for materials design. [9][10][11][12][13] Despite the innovation in the field of magnetocaloric materials science through the nanotechnological approach, the scientific community kept looking at the problem from the conventional perspective of employing the MCE by exposing the active magnetocaloric material to an external magnetic field.…”

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confidence: 99%

Near-room-temperature refrigeration through voltage-controlled entropy change in multiferroics

Binek

Burobina

2013

Applied Physics Letters

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Composite materials with large magnetoelectric effect are proposed for application in advanced near-room-temperature refrigeration. The key innovation rests on utilizing the magnetocaloric effect in zero applied magnetic fields. This approach promises sizable isothermal entropy change and virtually temperature-independent refrigerant capacity through pure voltage-control. It is in sharp contrast with the conventional method of exploiting the magnetocaloric effect through applied magnetic fields. We outline the thermodynamics and estimate an isothermal entropy change specifically for the La0.7Sr0.3MnO3/Pb(Mg1/3Nb2/3)O3-PbTiO3(001) two-phase composite material. Finally, we propose structural variations of two-phase composites, which help in overcoming the challenging task of producing nanostructured material in macroscopic quantities.

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“…Indeed the Curie temperature of MCMs can be modified by tuning the proportion of additive elements in order to increase the efficiency and the temperature span of multi-material AMR (Richard et al, 2004). This approach can significantly improve the efficiency of the MHP compared to non-layered AMR .…”

Section: Magnetic Heat Pumpmentioning

confidence: 99%

Sizing of a reversible magnetic heat pump for the automotive industry

Torregrosa-Jaime

Corberán

Vasile

et al. 2014

International Journal of Refrigeration

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This paper focuses on the design of an innovative air-conditioning system, namely a magnetocaloric air-conditioner for an electric minibus. An integrated design of the complete system is necessary, as the hot and cold side of the regenerator will work under dynamic conditions which depend on the instantaneous thermal load in the cabin.In order to assist the design of the system, a dynamic model has been developed for the cabin, the hydraulic loops and heat exchangers, and the magnetocaloric unit. This paper presents (i) a description of the dynamic models, (ii) an analysis of the operating conditions of the magnetocaloric unit and (iii) a discussion on the design of the magnetocaloric air-conditioner. The results show that 2 the electric minibus requests 1.60 kW of cooling power over a span of 37 K in cooling mode, and 3.39 kW of heating power over a span of 40K.

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Magnetic refrigeration: Single and multimaterial active magnetic regenerator experiments

Cited by 123 publications

References 8 publications

Enhanced refrigerant capacity and magnetic entropy flattening using a two-amorphous FeZrB(Cu) composite

Enhanced refrigerant capacity and magnetic entropy flattening using a two-amorphous FeZrB(Cu) composite

Near-room-temperature refrigeration through voltage-controlled entropy change in multiferroics

Sizing of a reversible magnetic heat pump for the automotive industry

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