Active Magnetic Regeneration - Magnetocaloric Energy Conversion: From Theory to Applications - page 136

c cooling power and the maximum COP
(obtained at the optimum utilization factor

In Fig. 4.22 , the maximum speci

— mass fl ow rate for each case) are

presented as a function of the magnetic eld. In this particular case the frequency of

the device was held constant at 3 Hz.
In Fig. 4.23 , the maximum speci c cooling power and the maximum COP are

presented as a function of the frequency of the operation (for a constant magnetic

eld of 1 T). Like for the results shown in Figs. 4.19 , 4.20 , 4.21 and 4.22 , the
utilization factor was varied in order to obtain the maximum values of the COP and
the maximum values for the speci

c cooling power per mass of magnetocaloric

material.
According to Fig. 4.22 , the maximum speci c cooling power can be obtained

with a Brayton-like AMR cycle, which shows slightly better cooling performance
than the Ericsson-like AMR cycle. However, the highest COP can be obtained with
the Ericsson-like AMR cycle. When compared to a Brayton-like and an Ericsson-
like AMR cycle, a substantially lower speci

c cooling power and a lower COP can
be obtained with the Carnot-like AMR cycle. The increases in the cooling power
and the COP with the magnetic eld are more evident for the Carnot-like AMR

cycle.

Fig. 4.22 a The maximum
speci c cooling power as a
function of the magnetic eld
for three different magnetic
refrigeration thermodynamic
cycles. b The maximum COP
as the function of the
magnetic eld for three
different magnetic
refrigeration thermodynamic
cycles