Active Magnetic Regeneration - Magnetocaloric Energy Conversion: From Theory to Applications - page 101

sides of the AMR, from the initial temperatures to the periodic steady state, is
shown in Fig. 4.5 a, while Fig. 4.5 b shows the temperature pro le along the AMR

during the establishment of the temperature span from the initial state to the point
where the periodic steady state is reached.
The dotted lines in Fig. 4.6 show the temperature pro

le at the beginning of a

particular phase, while the full lines show the pro le at its end. It should be noted

that these phases are the same as schematically shown in Fig. 4.2 . Figures 4.4 , 4.5
and 4.6 are reproduced using a numerical model of the AMR (with Gd as the
magnetocaloric material), which is presented in detail in Tu

š ek et al. [ 16 , 17 ].

4.1.1 Characteristics of an Ericsson-like AMR Cycle

An AMR can also be applied with some other thermodynamic cycles. This is
achieved by using different combinations of the (de)magnetization and fl uid fl ow

process simultaneously.
The Ericsson-like AMR cycle is, unlike the Brayton-like AMR cycle, based on
an isothermal (de)magnetization rather than adiabatic. In Fig. 4.7 the Ericsson-like
AMR cycle is schematically presented in a T

s diagram in the periodic steady state
(Fig. 4.7 a), together with the required magnetic eld prole and fluid flow regime
(Fig. 4.7 b). In this case, each part of the magnetocaloric material along the AMR
performs its own small Ericsson thermodynamic cycle. Even though the distribution
of the magnetic

-

eld can be similar to the case of the Brayton-like AMR cycle, the
Ericsson-like AMR cycle, in order to perform the isothermal (de)magnetization,

Fig. 4.7 The AMR Ericsson thermodynamic cycle and its characteristics