Academic literature on the topic 'Active magnet regenerator'
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Journal articles on the topic "Active magnet regenerator"
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Dall'Olio, S., M. Masche, Liang J., et al. "Novel design of a high efficiency multi-bed active magnetic regenerator heat pump." International Journal of Refrigeration 132 (December 9, 2021): 243–54. https://doi.org/10.1016/j.ijrefrig.2021.09.007.
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The design of a rotary active magnetic regenerator heat pump device with a multi-bed concept is presented. Important design features are the rotating two-pole magnet assembly, the laminated iron ring, the 13 fixed tapered regenerator beds, and the dynamically adjustable parallel flow circuit. The optimized magnet design was developed with optimally shaped segments and optimum remanence for the desired magnetic field distribution oscillating between 0 and 1.44 T in the air gap. The iron ring was laminated to reduce the eddy currents, allowing the device to run at cycle frequencies up to 3 Hz. The design of the regenerator housing was optimized with respect to parasitic losses and even flow distribution in both directions. Employing 3.4 kg of La(Fe,Mn,Si)<sub>13</sub>H<sub>y</sub> (CALORIVAC HS) refrigerant and at a hot reservoir temperature of 295 K and a cycle frequency of 0.5 Hz, the heat pump achieved a maximum second-law efficiency of 20.6 %, while providing a heating load of 340 W with a heating COP of 6.7 at a 10.3 K span. The COP values presented only consider the magnetic power and ideal pump power delivered to the AMR, neglecting the pump efficiency. At 1.2 Hz, the device produced a maximum heating power of 950 W while maintaining a 5.6 K span, resulting in a heating coefficient of performance and second-law efficiency of 7.0 and 11.6 %, respectively. The performance demonstrated in this paper could be an important milestone in the development of future magnetocaloric devices.
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Keawkamrop, Thawatchai, Ahmet Selim Dalkilic, Lazarus Godson Asirvatham, Jafar Amani, Omid Mahian, and Somchai Wongwises. "Experimental Investigation on the Performance of a Parallel Plate-Based Active Magnetic Regenerator." International Journal of Air-Conditioning and Refrigeration 26, no. 02 (2018): 1850018. http://dx.doi.org/10.1142/s2010132518500189.
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This paper describes a prototype of a linear reciprocating magnetic refrigerator using a gadolinium parallel plate. The new design of the regenerator, installation, and experiment is presented. The regenerator consists of a gadolinium plate and an inlet/outlet section. The thickness and length of the gadolinium plate are 1[Formula: see text]mm and 80[Formula: see text]mm, respectively. The gap between parallel plates is 0.1[Formula: see text]mm. Water is used as the heat transfer fluid. The permanent magnet structure used in the present study can generate a maximum magnetic field intensity of 0.94 T. The effects of surface roughness of the gadolinium parallel plate on the temperature span and cooling capacity are investigated. The results show that there is no significant effect of surface roughness on the magnetic refrigerator performance at a high utilization factor. The results from the present study are important for the design of magnetic refrigerators operating at room temperature.
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Park, Inmyong, Chankyeong Lee, Jiho Park, Seokho Kim, and Sangkwon Jeong. "Performance of the Fast-Ramping High Temperature Superconducting Magnet System for an Active Magnetic Regenerator." IEEE Transactions on Applied Superconductivity 27, no. 4 (2017): 1–5. http://dx.doi.org/10.1109/tasc.2017.2652324.
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Park, Inmyong, Chankyeong Lee, Jiho Park, Seokho Kim, and Sangkwon Jeong. "Ramping Operation of the Conduction-Cooled High-Temperature Superconducting Magnet for an Active Magnetic Regenerator System." IEEE Transactions on Applied Superconductivity 26, no. 4 (2016): 1–5. http://dx.doi.org/10.1109/tasc.2016.2524568.
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Masche, M., J. Liang, K. Engelbrecht, and C.R.H Bahl. "Efficient modulation of the magnetocaloric refrigerator capacity." International Journal of Refrigeration 145 (November 28, 2022): 59–67. https://doi.org/10.1016/j.ijrefrig.2022.10.005.
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Magnetocaloric energy conversion devices (e.g., room air conditioners and household refrigerators) have the potential to significantly reduce the emissions associated with refrigerant leakage into the atmosphere but still have lower efficiencies compared to mature vapor compression systems. The efficiency of a magnetocaloric cooling device derives not only from its design characteristics (e.g., solid refrigerant, hydraulic system, and magnet system) and its operating temperature span but also from its modulating capability. Owing to the lack of experimental data regarding this topic, the advantage of modulating the cooling capacity (i.e., the part-load performance) of an active magnetic regenerator prototype is demonstrated experimentally for the first time. The capacity modulation is carried out by means of regulating both the cycle frequency of the device and the volumetric flow rate of the heat transfer fluid. At a 14 K temperature span and a 1.4 Hz frequency, the magnetocaloric refrigerator prototype using 3.8 kg of gadolinium provided a maximum cooling capacity of 452 W with an appreciable coefficient of performance of 3.2, which corresponds to a second-law efficiency of 15.5 %. At part-load operating conditions, the device can produce a cooling capacity of 245 W with an increased second-law efficiency of 29.7 %, or a coefficient of performance of 6.2, making it more competitive with traditional vapor compression systems. In future studies, the experimental data obtained may be implemented in a dynamic building energy model to quantify the energy-saving benefits of part-load operation by estimating the overall system efficiency during a typical cooling season.
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Montazeri-Gh, M., and O. Kavianipour. "Investigation of the active electromagnetic suspension system considering hybrid control strategy." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 228, no. 10 (2013): 1658–69. http://dx.doi.org/10.1177/0954406213511430.
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This paper deals with an electromagnetic damper, which is composed of a permanent-magnet direct current motor, a ball screw, and a nut, as an active actuator. The main objective pursued in the paper is to study the active electromagnetic suspension system (AEMSS) considering hybrid control strategy (the hybrid control strategy is a linear combination of skyhook and groundhook control strategy). For this purpose, the nonlinear equations of the electric circuit of the AEMSS should be developed. Supposing linear conditions, the coefficients determination of the hybrid control strategy is carried out in the frequency domain using the genetic algorithm in order to improve the vehicle performance and energy regeneration simultaneously. Afterwards, the achieved coefficients are used to examine the designed AEMSS in the actual conditions for an actual road profile. The simulation results demonstrate that the designed AEMSS has the desired performance while energy can be regenerated from the road excitation and transformed into electric energy. Furthermore, it has been shown that the designed AEMSS regenerates energy during the ascent and descent of a bump and consumes energy near the top of the bump.
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Nielsen, Kaspar Kirstein, Christian R.H. Bahl, and Kurt Engelbrecht. "The effect of flow maldistribution in heterogeneous parallel-plate active magnetic regenerators." journal of physics d 46 (February 12, 2013): 105002. https://doi.org/10.1088/0022-3727/46/10/105002.
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The heat transfer properties and performance of parallel-plate active magnetic regenerators (AMRs) with heterogeneous plate spacing are investigated using detailed models previously published. Bulk heat transfer characteristics in the regenerator are predicted as a function of variation in plate spacing. The results are quantified through a Nusselt number scaling factor that is applied in a detailed 1D AMR model. In this way, the impact of flow maldistribution due to heterogeneous parallel plate stacks on AMR performance is systematically investigated. It is concluded that parallel-plate stacks having a standard deviation greater than about 5% on their plate spacing are severely penalized in terms of both cooling power and achievable temperature span due to the inhomogeneity of the stacks.
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Masche, M., J. Liang, K. Engelbrecht, and C.R.H Bahl. "Improving magnetic cooling efficiency and pulldown by varying flow profiles." Applied Thermal Engineering 215 (July 13, 2022): 118945. https://doi.org/10.1016/j.applthermaleng.2022.118945.
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Magnetic refrigeration systems are promising cooling solutions that employ the active magnetic regenerator refrigeration cycle to achieve practical temperature spans and environmental benefits. The hydraulic system that ensures a continuous flow of the heat transfer fluid through the system with a reciprocating flow in each regenerator bed is critical to the performance of the refrigeration cycle. Hence, we investigate the characteristics of the parallel flow circuit of a rotary active magnetic regenerator system, which consists of thirteen trapezoidshaped regenerators, each filled with 295 g of gadolinium spheres. Fluid flow is controlled via electrically actuated solenoid valves (both piloted and direct-acting) connected to the regenerator hot side. By varying the percentage of opening of the control valves, different blow fractions (or fluid flow waveforms) could be investigated. The objective of the study is twofold: (i) assess whether flow imbalances of the heat transfer fluid exist in the cold-to-hot blow (cold blow) and hot-to-cold blow (hot blow) directions, and (ii) determine whether there is an optimal value of the blow fraction both to maximize the cooling performance and realize a rapid temperature pulldown. Flow resistance measurements demonstrate a symmetric flow circuit design and resistances that are similar in the cold and hot blow directions. Moreover, for the studied temperature spans of 6 K and 16 K, the best blow fraction was found to be about 41.6 %. For instance, at a 16 K span, a utilization of 0.32, and at 1.4 Hz, increasing the fluid blow fraction from 25.0 to 41.6 % enhanced the cooling capacity and second-law efficiency from 70 to 330 W and from 2.6 to 17.4 %, respectively. In turn, lower blow fractions favored a more rapid temperature pulldown. The magnetocaloric system was about 30 % faster in establishing approximately 14 K temperature span when the blow fraction was reduced from 41.6 to 30.6 %. Hence, magnetic refrigeration systems can benefit greatly from solenoid valves, which allow the system to operate either in a time-saving mode or an energy-saving mode.
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Zanatta, Ana Paula, Ben Hur Bandeira Boff, Paulo Roberto Eckert, Aly Ferreira Flores Filho, and David George Dorrell. "Tubular linear permanent magnet synchronous machine applied to semi-active suspension systems." COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 37, no. 5 (2018): 1781–94. http://dx.doi.org/10.1108/compel-01-2018-0022.
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Purpose Semi-active suspension systems with electromagnetic dampers allow energy regeneration and the required control strategies are easier to implement than the active suspensions are. This paper aims to address the application of a tubular linear permanent magnet synchronous machine for a semi-active suspension system. Design/methodology/approach Classical rules of mechanics and electromagnetics were applied to describe a dynamic model combining vibration and electrical machines theories. A multifaceted MATLAB®/Simulink model was implemented to incorporate equations and simulate global performance. Experimental tests on an actual prototype were carried out to investigate displacement transmissibility of the passive case. In addition, simulation results were shown for the dissipative semi-active case. Findings The application of the developed model suggests convergent results. For the passive case, numerical and experimental outcomes validate the parameters and confirm system function and proposed methodology. MATLAB®/Simulink results for the semi-active case are consistent, showing an improvement on the displacement transmissibility. These agree with the initial conceptual thoughts. Originality/value The use of linear electromagnetic devices in suspension systems is not a novel idea. However, most published papers on this subject outline active solutions, neglect semi-active ones and focus on experimental studies. However, here a dynamic mechanical-electromagnetic coupled model for a semi-active suspension system is reported. This is in conjunction with a linear electromagnetic damper.
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Shen, Limei, Xiao Tong, Liang Li, Yiliang Lv, Zeyu Liu, and Junlong Xie. "Performance Simulation of the Active Magnetic Regenerator under a Pulsed Magnetic Field." Energies 15, no. 18 (2022): 6804. http://dx.doi.org/10.3390/en15186804.
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Magnetic refrigeration is acknowledged as a potential substitute for the conventional vapor-compression refrigeration technology, owing to its high efficiency and environmental friendliness. Existing magnetic refrigeration systems are mostly based on permanent magnets, owing to the characteristics of lower magnetic field intensity, non-uniform magnetic field distribution, and lower operating frequency due to the moving parts, which results in a low cooling capacity and small temperature difference. Thus, this study proposes the application of a pulsed magnetic field, with a high intensity and frequency, to a magnetic refrigeration system to achieve a high performance. A verified numerical model is established to investigate the thermodynamic cycle and cooling performance of an active magnetic regenerator (AMR). The transient and steady-state performances of AMR under pulsed and permanent magnetic fields are compared. The results suggest that an AMR can establish a stable temperature difference under a pulsed magnetic field that is 40 times faster than that under a permanent magnetic field. The maximum steady-state cooling capacity under a pulsed magnetic field is 2.5 times that under a permanent magnetic field when the temperature difference is 20 K. Additionally, the effects of pulsed magnetic field waveforms, frequency, and intensity on the performance of AMR are investigated under various utilization factors. These results can guide the improvement of room-temperature magnetic refrigerators.
Dissertations / Theses on the topic "Active magnet regenerator"
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Tura, Armando. "Energetic performance of regenerators in an active magnetic refrigerator." Doctoral thesis, Universita degli studi di Salerno, 2012. http://hdl.handle.net/10556/339.
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2010 - 2011<br>A technology that has the potential to create more efficient and compact refrigeration
devices is an Active Magnetic Regenerative Refrigerator (AMRR). An AMRR can operate
over a broad range of temperatures, as long as the appropriate refrigerant is implemented.
Thus this flexible technology can be used for small, efficient, and simple room temperature
refrigerators, as well as efficient gas liquefaction plants (AMRLs). Active Magnetic
Regenerator Refrigeration exploits the magnetocaloric effect displayed by magnetic materials
whereby a reversible temperature change is induced when the material is exposed to a
magnetic field. By using the magnetic materials in a regenerator as the heat storage medium
and as the means of work input, one creates an Active Magnetic Regenerator (AMR).
Active Magnetic Regenerator refrigeration systems still rely on correlations between fluid
and matrix material to determine the heat transfer coefficient. Typical configurations operate
in low Reynolds number and high Prandtl number ranges. For the oscillating fluid flow
through these regenerators correlations are used based on single blow experiments. There are
large discrepancies for low Reynolds numbers and high Prandtl numbers between the
commonly used correlations, even for typically used packed beds, such as packed stainless
steel spheres with uniform diameter of 1 mm. Therefore, this thesis addresses the
determination of the heat transfer coefficients for oscillating fluid flow with a new approach
which combines an analytical model with experimental data. In this work findings for a
passive regenerator test apparatus (PRTA) are determined based on thermal and hydraulic
effects. Experiments are performed for different operational parameters in respect of the low
Reynolds number range, for varying fluid flow frequencies, mass flow rates and heat loads.
The generated experimental data are the input for the analytical model for the heat transfer
coefficient determination. The results are compared to a commonly used correlation for
regenerators like Wakao and Engelbrechts correlations. [edited by author]<br>X n.s.
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Bayer, Daniel Nicholas. "The Magnetocaloric Effect & Performance of Magnetocaloric Materials in a 1D Active Magnetic Regenerator Simulation." Wright State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=wright1578587695272946.
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Almanza, Morgan. "La réfrigération magnétique : conceptualisation, caractérisation et simulation." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENT105/document.
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La réfrigération magnétique est une alternative pertinente dans un contexte où les gaz réfrigérants sont soumis à des restrictions environnementales. Ces restrictions nécessitent l'évolution de la technologie actuelle ou bien l'émergence d'une nouvelle, d'où l'opportunité pour la réfrigération magnétique de prouver son potentiel. En effet, elle pourrait s'avérer énergiquement plus efficace et avec des densités de puissance supérieure. Ces travaux de thèse apportent des réponses sur le potentiel de la réfrigération magnétique. Dans cette logique, la thermodynamique et le magnétisme, outils indispensables à notre étude, sont développés dans le cas des matériaux à effet magnétocalorique. Puis, nous verrons que les caractérisations de ces derniers sont en mesure de fournir des modèles matériaux cohérents et réalistes, si des précautions sont prises. L'effet magnétocalorique étant limité en termes de variation de température, nous allons étudier différentes structures de réfrigération. Enfin, des modèles numériques sont développés pour permettre d'optimiser les structures à régénérations actives, qui sont les plus utilisées. Ces modèles doivent permettre de dimensionner des systèmes proches de leurs optimums<br>Magnetic refrigeration is a relevant alternative in consideration of environmental restrictions of refrigerants gases. These restrictions require to improve the current technology or to pave the way for a new one, hence the opportunity for magnetic refrigeration to demonstrate its potential. Indeed, it could be energetically efficient and with higher power densities. This work aims to estimate the potential of magnetic refrigeration. Magnetism and thermodynamic, essential tools for our study, are developed in a case of magnetocaloric effect. With some care, we show that material characterizations are able to give consistence and relevant model. Magnetocaloric effect suffers of small temperature variations; therefore structures that increase the temperature span and give competitive system are studied. Finally numerical models are developed to optimize active magnetic regenerators, which are currently the most used. These models are used to calculate and design systems close to their optimum
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Lionte, Sergiu. "Caractérisation, étude et modélisation du comportement thermomagnétique d'un dispositif de réfrigération magnétique à matériaux non linéaires et point de Curie proche de la température ambiante." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAD008/document.
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L’objectif de ce travail est de développer un modèle multi-physique et multi-échelle de Régénérateur Magnétique Actif en vue d’optimiser le fonctionnement d’un système de réfrigération magnétique. Le modèle numérique développé lors de cette thèse est un modèle multi-physique et multi-échelle qui prend en compte trois phénomènes distincts (le magnétisme, la fluidique et le transfert de chaleur), chacun à une échelle différente (micro-échelle, mini-échelle et macro-échelle). Une étude expérimentale a été menée afin de déterminer les propriétés thermophysiques des matériaux magnétocaloriques et d’intégrer les résultats de ces mesures dans le modèle numérique. Le modèle a été validé par une comparaison avec des données expérimentales et les résultats obtenus ont montré une bonne corrélation entre les résultats du modèle et les mesures. Enfin, le modèle a été exploité par une analyse de sensibilité des paramètres en vue d’étudier le fonctionnement ainsi que les performances du système. Ce modèle permettra d’identifier une stratégie de conception optimale d’un Régénérateur Magnétique Actif afin de concevoir des systèmes de réfrigération magnétique performants<br>The objective of this work is the developing of a multi-physics and multi-scale numerical model of an Active Magnetic Regenerator in order to optimize the operation of a magnetic refrigeration system. The numerical model developed in this thesis is a multi-physics and multi-scale model that takes into account simultaneously three distinct phenomena (magnetism, fluid flow and heat transfer), each on a different scale (micro-scale, mini-scale scale and macro-scale). An experimental study was conducted to determine the thermophysical properties of magnetocaloric materials and integrate the results of these measurements in the numerical model. The model has been validated by comparison with experimental data and the results showed a good correlation between the model results and measurements. Finally, the model was exploited by an analysis of parameter sensitivity allowing studying the operation and performance of the system. This model will identify an optimal design strategy of an Active Magnetic Regenerator in order to design high-performance magnetic refrigeration systems
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Mira, Mohamed Amine. "Modélisation et conception optimale d'un système de réfrigération magnétocalorique." Thesis, Besançon, 2016. http://www.theses.fr/2016BESA2030/document.
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La réfrigération magnétique est une technologie émergente grâce à des avantages considérables par rapport aux technologies de réfrigération classiques. Cette technologie basée sur l’effet magnétocalorique offre d’importants avantages environnementaux car d’une part l’efficacité théorique des cycles utilisés est supérieure à celle des technologies classiques et d’autre part son fonctionnement ne nécessite pas une utilisation de gaz/vapeur `a fort effet de serre. En revanche des verrous scientifiques restent à lever, Le modèle multi-physique proposé dans cette thèse à pour but d’améliorer la précision de calcul. Il consiste à coupler un modèle 3D magnétostatique résolu par la méthode des éléments finis, un modèle magnétocalorique analytique et un modèle thermo-fluidique résolu par méthode des différences finies. Parallèlement, un banc d’essais a été conçu, optimisé et réalisé, ce banc permettra de faire des mesures fines des différents phénomènes qui interagissent dans la réfrigération magnétique<br>The magnetic refrigeration technology is a promising alternative technology to the production of cold. The work of this thesis deals with studying and designing a magnetic refrigeration prototype. A multiphysic model is developed, this model taking into account several magnetic and magnetocaloric aspect that never dealt in the literature. It is used to investigate the influence of a range of parameters on the performance of the AMR. A new test bench of magnetic refrigeration is also designed, it is based on a particular electromagnet that was optimally realized. The magnetic performances are showed and concord with design prevision. Finally, suggestions for future works are provided based on the knowledge presented here
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Brédy, Philippe. "Etude d'un cycle de réfrigération magnétique par régénération active entre 15 et 4,2 kelvins." Grenoble 1, 1989. http://www.theses.fr/1989GRE10004.
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L'etude experimentale est realisee en partant d'une source chaude a 14 k; ce qui permet d'atteindre des puissances froides de 20 mw sur un bain d'helium liquide a 4,2 k et un facteur de merite de la boucle de refrigeration voisin de 20%. Differentes geometries de regenerateur sont utilisees et un modele numerique de simulation est developpe
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Torregrosa, Jaime Bárbara. "Modelling and analysis of an air-conditioning system for vehicles based on magnetocaloric refrigeration." Doctoral thesis, Universitat Politècnica de València, 2016. http://hdl.handle.net/10251/68503.
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[EN] This PhD thesis studies the application of the magnetic refrigeration technology in the air-conditioning system of automobiles. Thermal models of each of the components of such a system have been developed with the purpose of determining accurately its global performance.
A dynamic one-dimensional model of a parallel-plate active magnetic regenerator (AMR) has been developed. The model is based in a new numerical scheme that reduces the computation time by 88% compared to the most commonly employed method. The model reproduces very accurately the passive regenerator cases with analytic solution and has been thoroughly validated against experimental results of both passive regenerator and AMR tests. The inclusion in the model of the magnetocaloric properties experimentally measured with a sample of the employed material, the demagnetizing effect, the fluid flow maldistribution and the losses to the ambient in the experimental setup have all been keys to obtain a good agreement with the experiments. The influence of the uncertainties and simplifications assumed when modelling these physical phenomena has been analyzed in detail, which has allowed the validation of different approaches.
Besides, a dynamic model of the air-conditioning (AC) system of an electric vehicle has been developed. Thermal models of each of the system components have been included, namely the cabin, the hydraulic loops with the air-to-coolant heat exchangers and the electric auxiliaries. The modelling methodology employed is based on the combination of the conservation equations with the semi-empirical fitting of the global heat transfer coefficient. Excellent validation results have been obtained with experimental results in a wide range of operating conditions.
The vehicle model has been employed to obtain the cooling and heating demand of a commercial full electric minibus, as well as the working temperatures. A broad optimization study has been carried out with the AMR model with the purpose of determining the design and working parameters of such a refrigerator that fulfil the cooling requirements of the vehicle with a minimum combined total system mass (affecting the weight of the vehicle and the economic cost) and electric consumption. The electric demand of the electrical AC auxiliaries has also been considered. Additionally, the heating performance of the optimal designs has been calculated. The application of AMR refrigerators in mobile air-conditioning systems is analyzed in comparison to the features of current vapor-compression systems.<br>[ES] En la presente tesis doctoral se ha estudiado la aplicación de un refrigerador magnético en un sistema de aire acondicionado para automóviles. Con el fin de determinar las prestaciones de dicho sistema de manera global y precisa, se ha desarrollado un modelo térmico de cada uno de sus componentes.
Por un lado, se ha desarrollado un modelo dinámico unidimensional de regenerador magnético activo (AMR) de placas planas paralelas, basado en un nuevo esquema numérico que reduce el tiempo de cálculo hasta en un 88% respecto al esquema más empleado. El modelo reproduce con gran exactitud los casos de regenerador con solución analítica y ha sido validado exhaustivamente con resultados experimentales funcionando como regenerador pasivo y como AMR. Para obtener buenos ajustes ha sido clave la inclusión en el modelo de las propiedades magnetocalóricas medidas experimentalmente con una muestra del material empleado, el efecto desmagnetizante, la mala distribución del fluido y las pérdidas hacia el ambiente del montaje experimental. La influencia de las incertidumbres y las simplificaciones en el modelado de estos fenómenos se ha analizado detalladamente, lo cual ha permitido validar diferentes aproximaciones.
Por otro lado, se ha desarrollado un modelo dinámico del sistema de aire acondicionado de un vehículo eléctrico. Se incluye el modelo térmico de la cabina, los bucles hidráulicos para la distribución de la potencia térmica con los intercambiadores de calor agua-aire y los auxiliares eléctricos. La metodología empleada para el desarrollo de estos modelos, basada en la combinación de ecuaciones de conservación con el ajuste semi-empírico de los coeficientes globales de transmisión de calor, ha producido excelentes resultados de validación con resultados experimentales en un amplio rango de condiciones de funcionamiento.
El modelo del vehículo se ha empleado para obtener la demanda de refrigeración y calefacción de un minibús eléctrico comercial, así como las temperaturas de funcionamiento del sistema. Con el modelo de AMR se ha llevado a cabo un amplio estudio de optimización para determinar los parámetros de diseño y de funcionamiento de dicho refrigerador que cubren las necesidades de refrigeración del vehículo una masa del conjunto del sistema y un consumo eléctrico mínimos, incluyendo el consumo de los auxiliares. Adicionalmente se han calculado las prestaciones de calefacción de las combinaciones óptimas. La aplicabilidad de este sistema en automóviles se analiza en comparación con un sistema equivalente de compresión de vapor.<br>[CAT] En aquesta tesi doctoral s'ha estudiat l'aplicació d'un refrigerador magnètic en un sistema d'aire condicionat per a automòbils. A fi de determinar les prestacions d'aquest sistema de manera global i precisa, s'ha desenvolupat un model tèrmic de cadascun dels components.
D'una banda, s'ha desenvolupat un model dinàmic unidimensional de regenerador magnètic actiu (AMR) de plaques planes paral·leles, basat en un nou esquema numèric que redueix el temps de càlcul fins d'un 88% respecte a l'esquema més emprat. El model reprodueix amb gran exactitud els casos de regenerador amb solució analítica, i ha sigut validat exhaustivament amb resultats experimentals funcionant com a regenerador passiu i com a AMR. Per a obtenir bons ajustos ha sigut clau la inclusió en el model de les propietats magnetocalòriques mesurades experimentalment amb una mostra del material emprat, l'efecte desmagnetitzador, la mala distribució del fluid i les pèrdues cap a l'ambient del muntatge experimental. La influència de les incerteses i les simplificacions en la modelització d'aquests fenòmens s'ha analitzat detalladament, la qual cosa ha permès validar diferents aproximacions.
D'altra banda, s'ha desenvolupat un model dinàmic del sistema d'aire condicionat d'un vehicle elèctric. S'hi inclouen el model tèrmic de la cabina, els bucles hidràulics per a la distribució de la potència tèrmica amb els bescanviadors de calor aigua-aire i els auxiliars elèctrics. La metodologia emprada per al desenvolupament d'aquests models, basada en la combinació d'equacions de conservació amb l'ajust semiempíric dels coeficients globals de transmissió de calor, ha produït excel·lents resultats de validació amb resultats experimentals en un ampli rang de condicions de funcionament.
El model del vehicle s'ha emprat per a obtenir la demanda de refrigeració i calefacció d'un minibús elèctric comercial, així com les temperatures de funcionament del sistema. Amb el model d'AMR s'ha dut a terme un ampli estudi d'optimització per determinar els paràmetres de disseny i de funcionament de la refrigeradora esmentada que cobreixen les necessitats de refrigeració del vehicle, una massa del conjunt del sistema i un consum elèctric mínims, incloent el consum dels auxiliars. Addicionalment s'han calculat les prestacions de calefacció de les combinacions òptimes. L'aplicabilitat d'aquest sistema en automòbils s'analitza comparant-la amb la d'un sistema equivalent de compressió de vapor.<br>Torregrosa Jaime, B. (2016). Modelling and analysis of an air-conditioning system for vehicles based on magnetocaloric refrigeration [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/68503<br>TESIS<br>Premiado
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Teyber, Reed. "System optimization and performance enhancement of active magnetic regenerators." Thesis, 2018. https://dspace.library.uvic.ca//handle/1828/9440.
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Energy conversion devices using solid-state magnetocaloric materials have the potential to reduce energy consumption and mitigate environmental pollutants. To overcome the limited magnetic entropy change of magnetocaloric materials, magnetic refrigeration devices typically use the active magnetic regenerator (AMR) cycle. AMR devices have demonstrated promising performance, however costs must be reduced for broad market penetration. Although the magnet cost is of greatest importance for commercialization, literature has decoupled magnet design from AMR optimization. And while multilayered regenerators can improve performance without increasing cost, a number of questions remain unanswered as a result of the prohibitive parameter space.
This dissertation explores methods of improving AMR performance and decreasing cost both at the subsystem level, namely the magnetocaloric regenerator, fluid flow system and magnetic field source, and the device level by coupling the regenerator and magnet design problems in a cost optimization framework. To improve AMR performance, multilayered regenerators with second-order magnetocaloric materials are experimentally and numerically investigated, yielding insight on how individual layers behave and interact over a wide range of regenerator compositions and operating parameters. An efficient AMR modeling approach is presented where individual layers are treated as cascaded AMR elements, and simulations are in excellent agreement with experiments. Insights from the computationally efficient model are used to inform device modifications, and a no-load temperature span of 40 K is measured in close proximity to the simulated optimum; one of the highest in literature.
To simultaneously decrease AMR costs, a permanent magnet optimization framework is explored that is conducive to nonlinear objectives and constraints. This is used to investigate the optimal design of permanent magnet structures with reduced rare-earth permanent magnet materials. The regenerator and magnet design problems are then coupled in a permanent magnet topology optimization to minimize the combined capital and operating costs of an AMR. The optimal magnetic field waveform and the optimal means of producing this waveform are simultaneously obtained. The lifetime ownership costs of the optimized AMR device are shown to be in the realm of existing entry-level cooling devices. The presented cost optimization framework is of interest to both scientists and engineers, and demonstrates the importance of fast AMR models in identifying system designs, regenerator compositions and operating regimes that increase AMR performance and decrease cost.<br>Graduate
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Tura, Armando. "Design and Analysis of a Nested Halbach Permanent Magnet Magnetic Refrigerator." Thesis, 2013. http://hdl.handle.net/1828/4783.
Full textAbstract:
A technology with the potential to create efficient and compact refrigeration devices is
an active magnetic regenerative refrigerator (AMRR). AMRRs exploit the
magnetocaloric effect displayed by magnetic materials whereby a reversible temperature
change is induced when the material is exposed to a change in applied magnetic field. By
using the magnetic materials in a regenerator as the heat storage medium and as the
means of work input, one creates an active magnetic regenerator (AMR). Although
several laboratory devices have been developed, no design has yet demonstrated the
performance, reliability, and cost needed to compete with traditional vapor compression
refrigerators. There are many reasons for this and questions remain as to the actual
potential of the technology.
The objective of the work described in this thesis is to quantify the actual and potential
performance of a permanent magnet AMR system. A specific device configuration
known as a dual-nested-Halbach system is studied in detail. A laboratory scale device is
created and characterized over a wide range of operating parameters. A numerical model
of the device is created and validated against experimental data. The resulting model is
used to create a cost-minimization tool to analyze the conditions needed to achieve
specified cost and efficiency targets.
Experimental results include cooling power, temperature span, pumping power and
work input. Although the magnetocaloric effect of gadolinium is small, temperature
spans up to 30 K are obtained. Analysis of power input shows that the inherent magnetic
work is a small fraction of the total work input confirming the assumption that potential
cycle efficiencies can be large. Optimization of the device generates a number of areas
for improvement and specific results depend upon targeted temperature spans and cooling
powers. A competitive cost of cooling from a dual-nested-Halbach configuration is
challenging and will depend on the ability to create regenerator matrices with near-ideal
adiabatic temperature change scaling as a function of temperature.<br>Graduate<br>0548<br>0791<br>0607<br>atura@uvic.ca
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Burdyny, Thomas. "Simplified modeling of active magnetic regenerators." Thesis, 2012. http://hdl.handle.net/1828/4210.
Full textAbstract:
Active magnetic regenerator (AMR) refrigeration is an alternative technology to conventional vapor-compression refrigerators that has the potential to operate at higher efficiencies. Based on the magnetocaloric effect, this technology uses the magnetization and demagnetization of environmentally neutral solid refrigerants to produce a cooling effect. To become competitive however, a large amount of research into the optimal device configurations, operating parameters and refrigerants is still needed. To aid in this research, a simplified model for predicting the general trends of AMR devices at a low computational cost is developed. The derivation and implementation of the model for an arbitrary AMR is presented. Simulations from the model are compared to experimental results from two different devices and show good agreement across a wide range of operating parameters. The simplified model is also used to study the impacts of Curie temperature spacing, material weighting and devices on the performance of multilayered regenerators. Future applications of the simplified AMR model include costing and optimization programs where the low computational demand of the model can be fully exploited.<br>Graduate
Book chapters on the topic "Active magnet regenerator"
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Meddeb, Zina. "Modelling of Active Magnetic Regenerative Refrigeration System Performance by New Approaches." In Advances in the Modelling of Thermodynamic Systems. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-7998-8801-7.ch010.
Full textAbstract:
This work aimed to study the coefficient of performance (COP) of an active magnetic regenerative refrigeration (AMRR) system by new analytical approaches of magnetic work Wm(B,x,y) and magnetocaloric effect MCE (T,B). Those approaches were applied to a permanent magnet magnetic refrigerator. The studied refrigeration system consisted of four regenerators, each of which was formed by parallel plates of gadolinium, a circulation pump, a rotating magnet, and two heat exchangers. The heat transfer fluids used were water and gallium. A resolution of the continuity equation, the amount of movement equation, and the heat equation were carried out in order to study the temperature profile in both the regenerator and the fluid. Furthermore, the authors deduced the temperatures at the inlet and the outlet of the heat exchangers in order to establish a thermal balance.
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Aprea, Ciro, Adriana Greco, Angelo Maiorino, and Claudia Masselli. "Magnetocaloric as Solid-State Cooling Technique for Energy Saving." In Advances in Human Services and Public Health. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-3576-9.ch012.
Full textAbstract:
Magnetocaloric is an emerging cooling technology arisen as alternative to vapor compression. The main novelty introduced is the employment of solid-state materials as refrigerants that experiment magnetocaloric effect, an intrinsic property of changing their temperature because of the application of an external magnetic field under adiabatic conditions. The reference thermodynamic cycle is called active magnetocaloric regenerative refrigeration cycle, and it is Brayton-based with active regeneration. In this chapter, this cooling technology is introduced from the fundamental principles up to a description of the state of the art and the goals achieved by researches and investigations.
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Shikuku, Victor O., Chispin O. Kowenje, and Wilfrida N. Nyairo. "Fundamentals and Sources of Magnetic Nanocomposites and Their Sorption Properties." In Research Anthology on Synthesis, Characterization, and Applications of Nanomaterials. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-8591-7.ch028.
Full textAbstract:
Over the years, adsorption has been the most widely applied technique for pollutants remediation in conventional water and wastewater treatment regimes with commendable results. Consequently, multiple adsorbents have been synthesized, characterized and tested for various pollutants sequestration such as; heavy metals, dyes, pharmaceutically active ingredients, among others, in aqueous media. Unfortunately, most of the sorbents face many inherent limitations such as high production cost, difficult separation of adsorbent from solution, and complex synthesis processes. Therefore, an efficient adsorbent that would be sustainably adopted for industrial application in wastewater treatment requires, among other properties, a simple and efficient recovery step from a continuous flowing system. The regenerated adsorbent must also possess near original properties after several cycles of reuse thereby resulting to low capital investment. To address this challenge, studies conducted in the past few years incorporating magnetism in both natural and synthetic sorbents to improve their removal from water via magnetic separation have yielded stupendous results compared to conventional technologies. This chapter concisely discusses synthesis methods and adsorption capacities and mechanisms of selected magnetic nanocomposite adsorbents under diverse physicochemical conditions for removal of cations, dyes and organic pollutants from wastewater. Magnetic nanocomposites present eco-friendly properties and are potential alternatives for application in water purification processes subject to commercial viability evaluation before practical use.
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Hanaei, Shirin B., and Yvonne Reinwald. "Application of Bioceramics to Cancer Therapy." In Applications of Nanomaterials in Medical Procedures and Treatments. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815136951123040008.
Full textAbstract:
Despite the great medical developments, cancer remains the main cause of death amongst individuals under 85 years. Novel therapeutic approaches for cancer therapy are constantly being developed, and bioactive ceramics show great promise in this respect. Bioceramics contain inorganic components, which help in the repair, replacement, and regeneration of human cells; for that reason, their use is growing in scope. Bioceramics have a flexible nature and can be modified with biologically active substances for a particular treatment or improvement of tissue or organ functionality. Materials, including glass-ceramics and calcium phosphate, can be loaded with specific drugs, growth factors, peptides, and hormones in a particular fashion. Also, for the elimination of infections and inflammations after surgery, the surface of bioceramics can be modified, and antibiotics can be introduced to prevent bacterial biofilm formation. In the context of bone cancer diagnosis and treatment, mesoporous bioceramics have demonstrated excellent properties not only for being osteoinductive and osteoconductive but also for drug delivery, therefore, being rendered as a remarkable platform for the creation of bone tissue engineering scaffolds for the purpose of bone cancer treatment. Furthermore, the creation of ceramic magnetic nanoparticles as thermoseeds for hyperthermia exhibits promising development for cancer treatment. The conjugation of ceramic nanoparticles with therapeutic agents and heat treatment via different magnetic fields improve the efficacy of hyperthermia to the extent that it makes them an alternative to chemotherapy. This chapter discusses the therapeutic value of bioceramics.
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Peri, Angela Denise. "A Smart Materials Driven Approach to the Interior Design of Cruise Ships." In Progress in Marine Science and Technology. IOS Press, 2023. http://dx.doi.org/10.3233/pmst230027.
Full textAbstract:
The cruise ship unit is often defined as a “floating city” where the presence of large, open and closed spaces reproduces, in terms of dimensions and functions, those of public and private civil architecture. The aim of this research activity is to identify a theoretical process of mutual interaction among these two fields and functional links between material, technology and design, starting from a scoping activity review of the currently constituent finishing materials. This can lead to a possible application of adaptive solutions, which mainly rely on the use of smart materials, where external stimuli induced by electric, magnetic, mechanical and thermal fields of force, as well as variations in environmental parameters (temperature, pH, humidity, lightness, noise and the possible presence of harmful substances) give rise to an active, reversible response which causes variations of the intrinsic properties as well as a change in their structure, composition, function or shape. All the potential applications will have to assess the compatibility with the marine environment, durability and compliance with the rules and include performance paints and inks, photocatalytic systems with self-sanitizing properties, fabrics with antibacterial and water-repellent properties which, together with a protective action, able to generate electricity if exposed to light. Some polymeric fibres can thermally modify their sensitivity to humidity and allow for better adaptability and reversible shrinkage; self-healing surfaces regenerate after the occurrence of a crack. It is possible to create devices integrated with sensors and actuators capable of reacting automatically, monitoring the status of an electronic system and to detect specific environmental and human parameters. These applications are shaping a new perception of reality which include intelligent materials as elements of a new design-driven language, where all the phases of the concept design become interactive, adaptive and conscious, in closer affinity with the dynamics of living beings.
Conference papers on the topic "Active magnet regenerator"
1
Lei, Tian, Kaspar K. Nielsen, and Kurt Engelbrecht. "Modelling and Simulation of Regenerators With Complex Flow Arrangements for Active Magnetocaloric Refrigeration." In ASME 2014 12th Biennial Conference on Engineering Systems Design and Analysis. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/esda2014-20146.
Full textAbstract:
Compared to a conventional vapor compression refrigeration system, a magnetocaloric refrigerator has many advantages, such as potentially high efficiency, low vibration and avoidance of refrigerants that deplete the ozone layer and cause the greenhouse effect. As a main component of the active magnetic regenerative refrigerator, the regenerator plays an important role in the cooling performance and efficiency of the whole system. However, the regenerator design is constrained by several external factors, such as the geometry of the magnetic field source and flow resistance. In this work, novel regenerators with complex flow arrangements, providing high performance at lower pressure drop, are investigated. Correspondingly a one dimensional model is presented and comparative studies between novel and conventional regenerators are carried out by simulation. The effect of regenerator geometries and different flow arrangements on the cooling performance, pressure drop and efficiency are investigated. In particular, the effect of so-called dead volume on the performance of a regenerator is researched.
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Tura, A. "Cryogenic Active Magnetic Regenerator Test Apparatus." In ADVANCES IN CRYOGENIC ENGINEERING: Transactions of the Cryogenic Engineering Conference - CEC. AIP, 2006. http://dx.doi.org/10.1063/1.2202511.
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Cararo, Jean Eduardo, Jaime Lozano, Paulo Trevizoli, Jader Barbosa, Andrew Rowe, and Reed Teyber. "OPTIMIZATION OF MULTILAYER ACTIVE MAGNETIC REGENERATORS." In 16th Brazilian Congress of Thermal Sciences and Engineering. ABCM, 2016. http://dx.doi.org/10.26678/abcm.encit2016.cit2016-0320.
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Rowe, A. "Demagnetizing Effects in Active Magnetic Regenerators." In ADVANCES IN CRYOGENIC ENGEINEERING: Transactions of the Cryogenic Engineering Conference - CEC. AIP, 2004. http://dx.doi.org/10.1063/1.1774870.
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Trevizoli, Paulo V., Jader R. Barbosa, Armando Tura, Daniel Arnold, and Andrew Rowe. "Modeling of Thermo-Magnetic Phenomena in Active Magnetic Regenerators." In ASME 2013 Heat Transfer Summer Conference collocated with the ASME 2013 7th International Conference on Energy Sustainability and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/ht2013-17108.
Full textAbstract:
The active magnetic regenerator (AMR) is at the heart of the thermo-magnetic Brayton cooling cycle. It consists of a porous matrix heat exchanger whose solid phase is a magnetocaloric material (solid refrigerant) that undergoes a reversible magnetic phase transition when subjected to a changing magnetic field. The cooling capacity of the cycle is proportional to the mass of solid refrigerant, operating frequency, volumetric displacement of the working fluid (generally an aqueous solution) and regenerator effectiveness. AMRs can be modeled via a porous media approach and a model has been developed to simulate the time-dependent fluid flow and heat transfer processes. Gadolinium (Gd) is usually adopted as a reference material for magnetic cooling at near room temperature and, in this study, its magnetic temperature change and physical properties were accounted for using a combination of experimental data and the Weiss-Debye-Sommerfeld theory. In this paper, the influence of the applied magnetic field waveform and of demagnetizing effects on the AMR performance is investigated numerically. An evaluation of the model is also carried out in the light of a comparison against experimental data for a regenerator containing spherical Gd particles.
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Tahavori, Maryamsadat, Christian Veje, Tian Lei, Kaspar K. Nielsen, and Kurt Engelbrecht. "Computationally efficient model of an active magnetic regenerator." In 2015 IEEE International Conference on Control System, Computing and Engineering (ICCSCE). IEEE, 2015. http://dx.doi.org/10.1109/iccsce.2015.7482172.
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Leonteva, Anna Ouskova, Michel Risser, Radia Hamane, Anne Jeannin-Girardon, Pierre Parrend, and Pierre Collet. "A hybrid optimization tool for active magnetic regenerator." In GECCO '22: Genetic and Evolutionary Computation Conference. ACM, 2022. http://dx.doi.org/10.1145/3520304.3529055.
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Rowe, A. M. "Design of an active magnetic regenerator test apparatus." In ADVANCES IN CRYOGENIC ENGINEERING: Proceedings of the Cryogenic Engineering Conference - CEC. AIP, 2002. http://dx.doi.org/10.1063/1.1472121.
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Fidelis Peixer, Guilherme, Jaime Lozano, and Jader Barbosa. "Designing an active magnetic regenerator for a fixed magnetic circuit." In 24th ABCM International Congress of Mechanical Engineering. ABCM, 2017. http://dx.doi.org/10.26678/abcm.cobem2017.cob17-1773.
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Dikeos, J. "Numerical Analysis of an Active Magnetic Regenerator (AMR) Refrigeration Cycle." In ADVANCES IN CRYOGENIC ENGINEERING: Transactions of the Cryogenic Engineering Conference - CEC. AIP, 2006. http://dx.doi.org/10.1063/1.2202512.
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