Performance improvement of magnetocaloric cascades through optimized material arrangement

Patent metadata

Field	Value
Publication number	US-9915447-B2
Application number	US-201514978679-A
Country	US
Kind code	B2
Filing date	Dec 22, 2015
Priority date	Jan 24, 2013
Publication date	Mar 13, 2018
Grant date	Mar 13, 2018

Abstract

A magnetocaloric cascade containing at least three different magnetocaloric materials with different Curie temperatures, which are arranged in succession by descending Curie temperature, wherein none of the different magnetocaloric materials with different Curie temperatures has a higher layer performance Lp than the magnetocaloric material with the highest Curie temperature and wherein at least one of the different magnetocaloric materials with different Curie temperatures has as lower layer performance Lp than the magnetocaloric material with the highest Curie temperature wherein Lp of a particular magnetocaloric material being calculated according to formula (I):

Lp=m*dT ad,max

with
dT ad,max : maximum adiabatic temperature change which the particular magnetocaloric material undergoes when it is magnetized from a low magnetic field to high magnetic field during magnetocaloric cycling, m: mass of the particular magnetocaloric material contained in the magnetocaloric cascade.

First claim

The invention claimed is:

1. An apparatus selected from the group consisting of a refrigeration system, a climate control unit, and a heat pump, comprising:
a magnet; and
a magnetocaloric cascade comprising at least three different magnetocaloric materials having different Curie temperatures, which are arranged in succession by descending Curie temperature,
wherein none of the different magnetocaloric materials having different Curie temperatures has a higher layer performance Lp than the magnetocaloric material having the highest Curie temperature; and
wherein at least one of the different magnetocaloric materials having different Curie temperatures has a lower layer performance Lp than the magnetocaloric material having the highest Curie temperature;
wherein Lp of a particular magnetocaloric material is calculated according to a formula:
Lp=m*dT ad,max

where
dT ad,max is a maximum adiabatic temperature change that the particular magnetocaloric material undergoes when it is magnetized from a low magnetic field to high magnetic field during magnetocaloric cycling, and
m is a mass of the particular magnetocaloric material in the magnetocaloric cascade.

2. The apparatus according to claim 1 , wherein none of the different magnetocaloric materials having different Curie temperatures has a lower layer performance Lp than the magnetocaloric material having the lowest Curie temperature.

3. The apparatus according to claim 1 , wherein the layer performance Lp of the magnetocaloric material having the highest Curie temperature is 2 to 100% higher than the layer performance Lp of each of the other different magnetocaloric materials having a different Curie temperature.

4. The apparatus according to claim 1 , wherein the layer performance Lp of each of the different magnetocaloric materials having different Curie temperatures is equal or higher than the layer performance Lp of its adjacent magnetocaloric material having a lower Curie temperature.

5. The apparatus according to claim 1 , wherein the layer performance Lp of each magnetocaloric material layer is higher by 2 to 100% than the layer performance Lp of its adjacent magnetocaloric material layer having lower Curie temperature.

6. The apparatus according to claim 1 , wherein the mass of each of the different magnetocaloric materials having different Curie temperatures is equal or higher than the mass of the adjacent magnetocaloric material having a lower Curie temperature.

7. The apparatus according to claim 1 , wherein a difference in the Curie temperatures between two adjacent different magnetocaloric materials having different Curie temperatures is 0.5 to 6 K.

8. The apparatus according to claim 1 , wherein the magnetocaloric cascade comprises 3 to 100 different magnetocaloric materials having different Curie temperatures.

9. The apparatus according to claim 1 , wherein adjacent magnetocaloric materials having different Curie temperatures have a separation of 0.01 to 1 mm.

10. The apparatus according to claim 1 , wherein the magnetocaloric materials are insulated from one another by intermediate thermal and/or electrical insulators.

11. The apparatus according to claim 1 , wherein the magnetocaloric materials form a layer sequence, the layer thickness of each of the magnetocaloric materials being 0.1 to 100 mm.

12. The apparatus according to claim 1 , wherein the magnetocaloric materials are selected from
(1) compounds of the general formula (I)
(A y B 1−y ) 2+d C w D x E z   (I)

where
A is Mn or Co,
B is Fe, Cr or Ni,
at least two of C, D and E are different, have a non-vanishing concentration and are selected from the group consisting of P, B, Se, Ge, Ga, Si, Sn, N, As and Sb, where at least one of C, D and E is Ge, As or Si,
d is a number in the range from −0.1 to 0.1,
w, x, y, and z are numbers in the range from 0 to 1, where w+x+z=1;
(2) La- and Fe-based compounds of the general formulae (II) and/or (III) and/or (IV)
La(Fe x Al 1−x ) 13 H y or La(Fe x Si 1−x ) 13 H y   (II)

where
x is a number from 0.7 to 0.95,
y is a number from 0 to 3;
La(Fe x Al y Co z ) 13 or La(Fe x Si y Co z ) 13   (III)

where
x is a number from 0.7 to 0.95,
y is a number from 0.05 to 1−x,
z is a number from 0.005 to 0.5;
LaMn x Fe 2−x Ge  (IV)

where
x is a number from 1.7 to 1.95;
(3) Heusler alloys of a MnT t T p type where T t is a transition metal and T p is a p-doping metal having an electron count per atom e/a in the range from 7 to 8.5;
(4) Gd- and Si-based compounds of the general formula (V)
Gd 5 (Si x Ge 1−x ) 4   (V)

where x is a number from 0.2 to 1;
(5) Fe 2 P-based compounds;
(6) manganites of a perovskite type;
(7) compounds that comprise rare earth elements and are of the general formulae (VI) and (VII)
Tb 5 (Si 4−x Ge x )  (VI)

where x is 0, 1, 2, 3, 4; and
XTiGe  (VII)

where X is Dy, Ho, Tm; and
(8) Mn- and Sb- or As-based compounds of the general formulae (VIII), (IX), (X), and (XI)
Mn 2−x Z x Sb  (VIII) and

Mn 2 Z x Sb 1−x   (IX)

where
Z is Cr, Cu, Zn, Co, V, As, Ge,
x is from 0.01 to 0.5;
Mn 2−x Z x As  (X) and

Mn 2 Z x As 1−x   (XI)

where
Z is Cr, Cu Zn, Co, V, Sb, Ge,
x is from 0.01 to 0.5.

13. The apparatus according to claim 12 , wherein the magnetocaloric material is a quaternary compound of the general formula (I) comprising
Mn;
Fe;
P;
at least one element selected from the group consisting of Ge, Si and As;
and optionally Sb.

14. A process for producing the apparatus according to claim 1 , the process comprising:
shaping a powder of each particular magnetocaloric material to form each magnetocaloric material, and
subsequently packing the magnetocaloric materials to form the magnetocaloric cascade.

15. The apparatus according to claim 1 , wherein the magnet is configured to apply a magnetic field to the magnetocaloric cascade.

16. The apparatus according to claim 1 , further comprising a heat transfer medium.

Assignees

• Basf Se

Inventors

• Carroll Colman
• Rogge Olaf
• Reesink Bernard Hendrik
• Rowe Andrew
• Arnold Danny
• Tura Armando

Classifications

• H01F1/015 Primary

  Metals or alloys · CPC title

• F25B21/00 Primary

  Machines, plants or systems, using electric or magnetic effects · CPC title

• F25B2321/002

  by using magneto-caloric effects · CPC title