Active Magnetic Regeneration - Magnetocaloric Energy Conversion: From Theory to Applications - page 96

end of the chapter, a brief review on different processing techniques of AMRs is
presented and discussed.

4.1 Operation of an Active Magnetic Regenerator
(Different Thermodynamic Cycles with an AMR)

The operation of an AMR is generally based on four operational steps, as shown in
Fig. 4.2 . It should be noted that these four steps can also overlap and can be performed
simultaneously, which can lead to a number of different thermodynamic cycles [ 9 , 10 ].
However, the most basic, and by far the most widely applied, thermodynamic
cycle of the AMR is the Brayton-like cycle, which is based on the following four
operational phases (see Fig. 4.2 ):

￿ Magnetization each part of the magnetocaloric material along the AMR is

heated up due to the magnetocaloric effect (Fig. 4.2 a)

—

' ' —

￿ Fluid fl ow from the cold side (cold heat exchanger CHEX) through the

' ' —

heated magnetocaloric material to the hot side (hot heat exchanger HHEX)

in the magnetic uid heats up

(while the material cools down) and in the HHEX transfers the heat to the
surroundings (Fig. 4.2 b)

eld. During this process of heat transfer, the fl

Demagnetization each part of the magnetocaloric material along the AMR is

cooled down due to the magnetocaloric effect (Fig. 4.2 c)

—

￿

Fig. 4.2 Schematics showing the four basic operational phases of the AMR process for the
Brayton-like AMR cycle in a linear (reciprocating) device