Magnetic Field Sources - Magnetocaloric Energy Conversion: From Theory to Applications - page 88

continuous cooling and balance the magnetic forces; however, the device was
constructed only for experimental purposes for the investigation and characteriza-
tion of AMRs.

3.4.4 Halbach (3D) Magnet Assemblies

Besides the solutions in which the magnetic ux path in the magnet assembly can

be approximated by two dimensions, three-dimensional guidance of the magnetic
fl

fl

ux density in the desired direction (see
also Fig. 3.29 ). However, higher dimensions will be, in most cases, associated with
the complexity of the magnet assembly and the related costs for such a structure.
Figure 3.47 shows the magnet assembly designed by Chell and Zimm [ 61 ]. This
magnet assembly represents the rotary part of a device, which was presented by
Zimm et al. [ 62 ].
The magnet assembly rotates over the AMR beds, which are separated by an
angle of 30

ux can lead to an increase in the magnetic fl

° . The high- eld region of 1.5 T is provided at an angle of 60 ° on its

opposite sides.
Another magnet assembly, designed by Kitanovski et al. [ 63 ] and presented by
Egolf et al. [ 44 , 64 ], is shown in Fig. 3.48 . This design was made for a rotary ring
with magnetocaloric material beds. Two high and two low regions of magnetic eld

were provided, each on the opposite side of the magnet assembly. In Fig. 3.48 b, the
cross-section of the magnet assembly shows only the high magnetic eld regions.

For these, the Ansys simulations showed a magnetic fl ux density of 2.1 T. The

magnetic ux passes the magnetocaloric material in the radial direction. A soft iron

body envelopes the magnet assembly, thus, providing guidance of the magnetic

fl

fl ux

as well as magnetic shielding. It contains openings for the introduction of the fl uid

connection (shown in Fig. 3.48 a).

Fig. 3.47 The rotating
magnet assembly as designed
by Chell and Zimm [ 61 ]