Electrocaloric vs. magnetocaloric energy conversion / M. Ožbolt in International journal of refrigeration, Vol. 37 N° 1 (Janvier 2014)  

Public ISBD [article]  inInternational journal of refrigeration > Vol. 37 N° 1 (Janvier 2014) . - pp. 16-27 Titre : Electrocaloric vs. magnetocaloric energy conversion Titre original : Comparaisons des conversions d'énergie électrocalorique et magnétocalorique Type de document : texte imprimé Auteurs : M. Ožbolt, Auteur ; A. Kitanovski, Auteur ; Jaka Tušek, Auteur Année de publication : 2014 Article en page(s) : pp. 16-27 Note générale : refrigeration Langues : Anglais (eng) Mots-clés : Electrocaloric effect  magnetocaloric magnetic refrigeration  energy conversion  refrigeration Résumé : Currently, one of the most interesting alternatives to conventional compressor refrigeration is magnetic refrigeration. However, despite its great potential, some important obstacles, relating mostly to the relatively low power density and the related high costs, must be overcome. Another alternative, which also shows great potential, is electrocaloric refrigeration. Until recently, electrocaloric materials were not so common; however, a number of different electrocaloric materials exist today. Like magnetocalorics, these can be used in the form of a regenerator in order to increase the temperature span. Based on a previously developed numerical model, we have made a comparison between electrocaloric and magnetocaloric regenerators. The results suggest that electrocaloric energy conversion represents a serious alternative, not only to compressor-based technologies, but also to magnetocalorics. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713001655 [article] Electrocaloric vs. magnetocaloric energy conversion = Comparaisons des conversions d'énergie électrocalorique et magnétocalorique [texte imprimé] / M. Ožbolt, Auteur ; A. Kitanovski, Auteur ; Jaka Tušek, Auteur . - 2014 . - pp. 16-27. refrigeration Langues : Anglais (eng) in International journal of refrigeration > Vol. 37 N° 1 (Janvier 2014) . - pp. 16-27 Mots-clés : Electrocaloric effect  magnetocaloric magnetic refrigeration  energy conversion  refrigeration Résumé : Currently, one of the most interesting alternatives to conventional compressor refrigeration is magnetic refrigeration. However, despite its great potential, some important obstacles, relating mostly to the relatively low power density and the related high costs, must be overcome. Another alternative, which also shows great potential, is electrocaloric refrigeration. Until recently, electrocaloric materials were not so common; however, a number of different electrocaloric materials exist today. Like magnetocalorics, these can be used in the form of a regenerator in order to increase the temperature span. Based on a previously developed numerical model, we have made a comparison between electrocaloric and magnetocaloric regenerators. The results suggest that electrocaloric energy conversion represents a serious alternative, not only to compressor-based technologies, but also to magnetocalorics. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713001655

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Modeling of a two-stage magnetic refrigerator with wavy-structure gadolinium heat exchangers / D. Vuarnoz in International journal of refrigeration, Vol. 33 N° 4 (Juin 2010)  

Public ISBD [article]  inInternational journal of refrigeration > Vol. 33 N° 4 (Juin 2010) . - pp. 745-752 Titre : Modeling of a two-stage magnetic refrigerator with wavy-structure gadolinium heat exchangers Titre original : Modélisationon d’un réfrigérateur magnétique biétagé muni d’échangeurs de chaleur ondulés en gadolinium Type de document : texte imprimé Auteurs : D. Vuarnoz, Auteur ; A. Kitanovski, Auteur ; C. Gonin, Auteur Année de publication : 2010 Article en page(s) : pp. 745-752 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Magnetic refrigerator Two-stage system Modelling Simulation Performance-COP Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : In a rotary magnetic refrigerator a porous ring is turning in and out of a magnetic field region. The adiabatic demagnetization of the magnetocaloric material produces the “cold energy”. This is described by a discontinuous temperature decrease, known as adiabatic temperature difference. For such a machine a physical model has been developed, based on a mapping of the magneto-thermodynamic problem. In this model, in a basic centre cell, two coupled linear partial differential equations are solved, which have been programmed in the Modelica language. The operation of a magnetic refrigerator is simulated with numerous parameters. Steady state solutions are obtained to verify the coefficient of performance under stable operation conditions. Optimal running conditions – defined by maximum values of the coefficient of performance – are not presented in this article, but can now easily be obtained with the existing program. A simple regulation strategy is proposed and implemented into the program. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700709003119 [article] Modeling of a two-stage magnetic refrigerator with wavy-structure gadolinium heat exchangers = Modélisationon d’un réfrigérateur magnétique biétagé muni d’échangeurs de chaleur ondulés en gadolinium [texte imprimé] / D. Vuarnoz, Auteur ; A. Kitanovski, Auteur ; C. Gonin, Auteur . - 2010 . - pp. 745-752. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 33 N° 4 (Juin 2010) . - pp. 745-752 Mots-clés : Magnetic refrigerator Two-stage system Modelling Simulation Performance-COP Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : In a rotary magnetic refrigerator a porous ring is turning in and out of a magnetic field region. The adiabatic demagnetization of the magnetocaloric material produces the “cold energy”. This is described by a discontinuous temperature decrease, known as adiabatic temperature difference. For such a machine a physical model has been developed, based on a mapping of the magneto-thermodynamic problem. In this model, in a basic centre cell, two coupled linear partial differential equations are solved, which have been programmed in the Modelica language. The operation of a magnetic refrigerator is simulated with numerous parameters. Steady state solutions are obtained to verify the coefficient of performance under stable operation conditions. Optimal running conditions – defined by maximum values of the coefficient of performance – are not presented in this article, but can now easily be obtained with the existing program. A simple regulation strategy is proposed and implemented into the program. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700709003119

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New thermodynamic cycles for magnetic refrigeration / A. Kitanovski in International journal of refrigeration, Vol. 37 N° 1 (Janvier 2014)  

Public ISBD [article]  inInternational journal of refrigeration > Vol. 37 N° 1 (Janvier 2014) . - pp. 28-35 Titre : New thermodynamic cycles for magnetic refrigeration Titre original : Nouveaux cycles thermodynamiques pour le froid magnétique Type de document : texte imprimé Auteurs : A. Kitanovski, Auteur ; U. Plaznik, Auteur ; Jaka Tušek, Auteur Année de publication : 2014 Article en page(s) : pp. 28-35 Note générale : refrigeration Langues : Anglais (eng) Mots-clés : Magnetic refrigeration  active magnetic regenerator  thermodynamic cycle  energy efficiency  heat transfe Résumé : Most of the existing prototype devices for magnetic refrigeration are based on a thermodynamic cycle with an active magnetic regenerator (AMR) that operates as a Brayton-type regenerative magnetic refrigeration cycle. However, there are several other cycles that may potentially influence not only the efficiency, but also the cost, compactness and simplicity of magnetocaloric devices. In this article we discuss the possibility of introducing new thermodynamic cycles. This is supported by information about, and a comparison of, the corresponding magnetic field sources. We present the results of numerical analyses and compare the characteristics of different thermodynamic cycles under different operating conditions and for different magnetic field intensities. Guidelines for future work on new magnetic thermodynamic cycles are presented. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713001412 [article] New thermodynamic cycles for magnetic refrigeration = Nouveaux cycles thermodynamiques pour le froid magnétique [texte imprimé] / A. Kitanovski, Auteur ; U. Plaznik, Auteur ; Jaka Tušek, Auteur . - 2014 . - pp. 28-35. refrigeration Langues : Anglais (eng) in International journal of refrigeration > Vol. 37 N° 1 (Janvier 2014) . - pp. 28-35 Mots-clés : Magnetic refrigeration  active magnetic regenerator  thermodynamic cycle  energy efficiency  heat transfe Résumé : Most of the existing prototype devices for magnetic refrigeration are based on a thermodynamic cycle with an active magnetic regenerator (AMR) that operates as a Brayton-type regenerative magnetic refrigeration cycle. However, there are several other cycles that may potentially influence not only the efficiency, but also the cost, compactness and simplicity of magnetocaloric devices. In this article we discuss the possibility of introducing new thermodynamic cycles. This is supported by information about, and a comparison of, the corresponding magnetic field sources. We present the results of numerical analyses and compare the characteristics of different thermodynamic cycles under different operating conditions and for different magnetic field intensities. Guidelines for future work on new magnetic thermodynamic cycles are presented. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713001412

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