**3.10 The Slovenian system**

An interesting prototype of a rotary magnetic refrigerator (Tusek et al., 2009) has been built on the basis of permanent magnets at the University of Ljubljana in Slovenia. Their rotary magnetic refrigerator consisted of a rotating drum (cylinder) that rotated around an internally positioned stationary soft iron core and externally positioned stationary permanent magnets. As shown in Fig. 15, the magnetic structure was composed of four NdFeB permanent magnets and low carbon 1010 steel used as a soft ferromagnetic material, and two magnetic circuits existed to allow the rotary movement of the AMR's. After optimization of the magnet structure geometry, a range of magnetic field intensities from 0.05 T to 0.98 T was obtained in the air gaps. There were 34 AMR's in the rotary drum and each AMR had the dimensions 10 mm × 10 mm × 50 mm. Gd plates, with a thickness of 0.3 mm, were filled in the AMR's and the total mass of Gd was approximately 600 g. The prototype could operate up to a frequency of 4 Hz. This reference mainly focused on the experience in development of such a rotary magnetic refrigeration prototype and no experimental results were reported. However, first predictions according to the researchers are that approximately a 7 K temperature difference will be achieved (Yu, 2010).

Fig. 15. The rotary magnetic refrigerator developed at the University of Ljubljana in Slovenia (Tusek et al., 2009).
