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power generation thermodynamic cycles and their speci
c processes. Their work
was based on that of Tesla [
1
] and Edison [
2
], who had patented ideas on
“
pyro-
magnetic generators
”
. At this time, electric coils were used as the sources of the
magnetic
eld. However, there is no evidence that such devices were ever built.
At the end of 1950s, one of the
rst thermodynamic analyses of magnetocaloric
power generation was presented by Brillouin and Iskenderian [
3
]. This was soon
followed by other reports [
4
7
]. Whereas most of the early investigations consid-
ered magnetocaloric materials in their solid form, in the 1960s there was a lot of
interest in the idea of producing magnetic power generators by using magnetoca-
loric suspensions as the working
-
uids. Most of this pioneering work was per-
formed by Resler and Rosensweig [
8
,
9
]. Subsequent work in the 1980s considered
magnetocaloric power generators based on solid working materials [
10
fl
12
]. There
is no evidence that any real prototype device for power generation has been
developed.
With the discovery of the giant magnetocaloric effect in 1997 [
13
], which was
followed by a number of prototypes for magnetic refrigerators, magnetocaloric
power generation has again become an interesting topic. Furthermore, a knowledge
about many new materials and the possibility of layering these materials (in order to
have a potentially larger temperature span) also led to new activities in magnetic
power generation [
14
-
eld of
thermodynamics in recent years has been dedicated to magnetic refrigeration. This
is also the reason why the thermodynamic cycles presented in this chapter relate to
refrigeration. A discussion of aspects relating to power generation is therefore only
given in the Chap.
8
.
The earlier investigations that considered particular thermodynamic cycles were
performed by Resler and Rosensweig in the 1960s [
8
,
9
], who mostly did work on
magnetocaloric
-
22
]. Despite this, most of the published work in the
uids. Brown in 1976 [
23
], then Steyert in 1978 [
24
], analysed the
thermodynamics of solid magnetocaloric refrigerants, with the latter focused on a
magnetic Stirling cycle. Kirol and Mills in 1984 and 1985 [
25
] performed analyses
of the thermodynamics of magnetocaloric power generators with solid magnetoc-
aloric materials. Rosensweig in 1985 [
26
] published a topic on ferrohydrodynamics,
with a comprehensive description of the thermodynamics and the
fl
fl
uid dynamics of
magnetocaloric
fl
uids. Barclay [
27
] in 1990 investigated magnetocaloric heat
pumps.
No systematic approach has been employed by the research community to
evaluate the various magnetocaloric thermodynamic cycles. The
rst record of this
can be found in Chen et al. 1992 [
28
]. They performed a theoretical evaluation
based on four different magnetocaloric thermodynamic cycles: Carnot, Brayton,
Stirling, and the so-called
cycle. In the last of these, the authors
proposed a thermodynamic cycle that is similar to the Stirling cycle. However, there
is no evidence of any experimental results relating to such a cycle.
Since 1990 there have been a large number of publications related to the basics
of magnetocaloric thermodynamics [
29
“
ideal regenerative
”
38
].
-
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