Active Magnetic Regeneration - Magnetocaloric Energy Conversion: From Theory to Applications - page 141

Fig. 4.25 The dependence of the temperature span and the COP on the speci c cooling power for
three different types of magnetic refrigeration cycles for a gadolinium packed-bed AMR in a
magnetic eld change of 1 T for two different frequencies of operation (0.5 and 3 Hz) at U = 0.3

Fig. 4.26 The dependence of the temperature span and the COP on the speci c cooling power for
three different types of magnetic refrigeration cycles for a gadolinium parallel-plate AMR in a
magnetic eld change of 1 T for two different frequencies of operation (0.5 and 3 Hz) at U = 0.3

AMR cycle, and the smallest cooling power can be obtained with the Ericsson-like
AMR cycle.
The highest COP can be obtained with the Ericsson-like, followed by the Hybrid
AMR cycle, while the Brayton-like AMR cycle shows the lowest ef

ciency. There

are two factors that make the Ericsson and Hybrid cycles more ef cient than the

Brayton cycle, regardless of the irreversible, higher heat transfer losses. The rst
reason is a smaller amount of magnetic work that is de

ned as the total surface area
of each particle of magnetocaloric material in the T - s diagram. The other factor that
has a positive effect on the COP of the Ericsson-like and Hybrid AMR cycles is the
lower pressure drop. Since the fl uid fl ow period in the case of the Ericsson-like and