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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