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Abstract: In order to obtain a better reliability, consistency and accuracy of results obtained with a numerical simulation of an AMRR (active magnetic regenerator refrigerator), a dimensionless numerical model was developed, which can equally be used for determination of regenerator’s heat transfer coefficient and simulation of passive heat regenerators or AMRR operation. Regenerator’s heat transfer coefficient α f, is a crucial input parameter in the simulation of AMRR operation and has a primal effect on the outcome of a solution. This paper deals with a derived dimensionless model and discusses errors involved when using different models for heat transfer coefficient and AMRR operation simulation. [Copyright &y& Elsevier]

Abstract: Magnetic refrigeration, heating and power conversion technologies are interesting alternatives to the conventional refrigeration, heat pumping and different conventional energy conversion technologies. At present they all show a realistic potential to enter conventional markets, respectively to be applied in a few years. In this review paper, mainly magnetic refrigeration and magnetic heating are addressed and from these two technologies the main part is dedicated to magnetic refrigeration at room temperature. This article covers the demand of giving a complete list and description of existing magnetic heating and cooling prototypes up to the year 2010. Forty-one machines, their components and operation principles are presented in detail. [Copyright &y& Elsevier]

Abstract: This paper presents the study of the magnetic change of the magnetic flux density into the magnetocaloric materials (MCMs). The MCMs are shaped in thin parallel plates separated by a fluid forming together an insert. It is shown that keeping all the parameters equal, the unique modification of the orientation of the insert induces a change of the magnetic flux density into the magnetocaloric materials. Like all paramagnetic and ferromagnetic materials, the MCMs have variable magnetic permeability according to the density of flux that crosses them. The influence of a thermal circuit on a permanent magnetic circuit assembly is also evaluated. In order to ensure the heat exchange between the magnetocaloric materials and the outside space, the use of a heat transfer fluid is needed. The heat transfer fluid goes along the mini plates and is also placed inside the magnetic field. Because a fluid is generally a diamagnetic element, this increases the total magnetic reluctance of the assembly. Two different configurations named serial and parallel have been studied and evaluated in order to find the configuration that causes minimal disturbances to the magnetic flux and thus increases the magnetocaloric effect (MCE). Both configurations were also compared in respect to the induction obtained inside the vacuum gap of the magnet assembly. [Copyright &y& Elsevier]

Abstract: In the present paper we consider the problem of optimizing the cooling of a magnetocaloric refrigerator. In this work we first theoretically and then experimentally study the performance of a single material regenerator under different operating conditions. The basic principles of the design and implementation of our magnetic refrigerator prototype are presented as well as a new magnetic assembly of NdFeB permanent magnets. The design of the equipment uses a movement of relative displacement optimized for the phases of activation and inactivation of the magnetic field. Each part of the equipment is implemented in order to be controlled separately and to allow a large variety of the tests: gear pumps with individual control, sequence of programmable magnetocaloric cycle, unit control by programmable controller and application programming interface by color LCD touch screen, real-time processing data acquisition using a National Instruments System implemented on Independent PC, expelled heat using different standard heat exchangers. [Copyright &y& Elsevier]