Environmental Engineering Reference
In-Depth Information
Table 2.1 Some MCMs with their magnetocaloric properties near room temperature
Material
T
C
(K)
−Δ
s
M
(Jkg
−
1
K
−
1
)
Δ
T
ad
(K)
ʔ
B
(T)
q
R,max
(Jkg
−
1
)
References
Gd
*
293
3.1
3.3
1
913
[
38
]
Gd
0.9
Tb
0.1
286
2.3
1.9
1
1,148
[
43
]
*
Gd
5
Si
2
Ge
2
278
14
7.3
2
3,943
[
22
]
*
LaFe
11.06
Co
0.86
Si
1.08
*
276
6.1
2.3
1
1,690
[
38
]
LaFe
11.05
Co
0.94
Si
1.01
287
5.1
2.1
1
1,469
[
38
]
*
LaFe
10.96
Co
0.97
Si
1.07
289
5.3
2.2
1
1,537
[
38
]
*
La(Fe
0.88
Si
0.12
)
13
H
*
274
19
6.2
2
5,264
[
48
]
La(Fe
0.89
Si
0.11
)
13
H
1.3
*
291
24
6.9
2
7,066
[
48
]
La(Fe
0.88
Si
0.12
)
13
H
1.5
323
19
6.8
2
6,201
[
48
]
*
MnAs
318
31
4.7
2
9,930
[
52
]
*
MnFeP
0.45
As
0.55
*
306
12.5
2.8
1
3,842
[
55
]
Mn
1.1
Fe
0.9
P
0.47
As
0.53
292
11
2.8
1
3,227
[
55
]
*
LCSM (x =0)
267
5.9
2.0
1.2
1,581
[
59
]
*
LCSM (x = 0.055)
*
285
2.8
1
1.2
800
[
59
]
LCSM (x = 0.165)
332
1.8
0.93
1.2
598
[
59
]
*
An overview of a numerical and experimental analysis of layered AMRs is
presented in Sect.
4.2
. However, recently, a new material was presented by Barcza
et al. [
60
]. They presented a layered LaFe
13
−
x
−
y
Co
x
Si
y
material in which the Curie
temperature changes continuously along the length. They managed to produce such
a layered material by pressing several powders with different Curie temperatures on
top of each other with a subsequent sintering and diffusion treatment [
60
]. In this
manner gradients of the Curie temperature between 0.3 and 10 Kmm
−
1
were
obtained. The general idea is to make such a material in which the Curie temper-
ature gradient would linearly and continuously change along the length (Fig.
2.2
b).
2.2.6 Conclusions
In the above sections a brief review of some of the most common MCMs that
exhibit a MCE close to room temperature were presented. In this way the reader can
obtain a general impression about which direction to search in the study of magnetic
refrigeration, heat pumping or power generation. There are a number of extensive
and thorough reviews on MCMs of different sorts already published in the litera-
ture, if the reader needs to study MCMs in more detail.
In conclusion, Table
2.1
shows some of the most interesting types of MCMs
with regards to their MCE.
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