**Technological and Engineering Applications**

222 Trends in Electromagnetism – From Fundamentals to Applications

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Schercliff, J.A. (1956). The Flow of Conducting Fluids in Circular Pipes under Transverse Magnetic Fields, *J. of Fluid Mechanics*, Vol. 1, pp. 644-666, ISSN 0022-1120 Sterl, A. (1990). Numerical Simulation of Liquid-Metal MHD Flows in Rectangular Ducts, *J.* 

4077-0, Dordrecht-Boston-London, Netherlands-USA-England

*of Fluid Mechanics*, Vol. 216, pp. 161-191., ISSN 0022-1120

**10** 

*1Saudi Arabia 2Algeria* 

**Magnetic Refrigeration Technology** 

Houssem Rafik El-Hana Bouchekara1,2 and Mouaaz Nahas1

*1Department of Electrical Engineering, College of Engineering and Islamic Architecture,* 

Modern society largely depends on readily available refrigeration methods. Up till now, the conventional vapor compression refrigerators have been mainly used for refrigeration applications. Nonetheless, the conventional refrigerators – based on gas compression and expansion – are not very efficient because the refrigeration accounts for 25% of residential and 15% of commercial power consumption (Tishin, 1999). Moreover, using gases such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) have detrimental effects on our environment. Recently, the development of new technologies – such as magnetic refrigeration – has brought an alternative to the conventional gas compression

The magnetic refrigeration at room temperature is an emerging technology that has attracted the interest of researchers around the world (Bouchekara, 2008). Such a technology applies the magnetocaloric effect which was first discovered by Warburg (Bohigas, 2000; Zimm, 2007). In 1881, Warburg noticed an increase of temperature when an iron sample was brought into a magnetic field and a decrease of temperature when the sample was removed out of it. Thus, the magnetocaloric effect is an intrinsic property of magnetic materials; where it is defined as the response of a solid to an applied magnetic field which appears as a change in its temperature (Bohigas, 2000; Zimm, 2007). Such materials are called magnetocaloric materials. The magnetocaloric effect is present in all transition metals and lanthanide-series elements, which may have ferromagnetic behaviour. When a magnetic field is applied, the magnetic moments of these metals tend to align parralel to it, and the thermal energy released in this process produces the heating of the sample. The magnetic moments become randomly oriented when the magnetic field is removed, thus the

The ultimate goal of this technology would be to develop a standard refrigerator for home use. The use of magnetic refrigeration has the potential to reduce operating and maintenance costs when compared to the conventional method of compressor-based refrigeration. By eliminating the high capital cost of the compressor and the high cost of

**1. Introduction** 

technique (Manh, 2007).

ferromagnet cools down (Gschneidner, 1998).

*2Electrical Laboratory of Constantine "LEC", Department of Electrical Engineering,* 

**at Room Temperature** 

*Umm Al-Qura University, Makkah,* 

*Mentouri University – Constantine, Constantine,* 
