Performance improvement of magnetocaloric cascades through optimized material arrangement

• US 9,245,673 B2
• Filed: 01/23/2014
• Issued: 01/26/2016
• Est. Priority Date: 01/24/2013
• Status: Active Grant

• Current Assignee: BASF SE
• Original Assignee: BASF SE
• Inventors: Carroll, Colman, Rogge, Olaf, Reesink, Bernard Hendrik, Rowe, Andrew, Tura, Armando, Arnold, Danny
• Primary Examiner(s): Ali, Mohammad M
• Application Number:
  US14/162,123
• Publication Number:
  US 20140202171A1
• Time in Patent Office: 733 Days
• Field of Search: 62/31, 62/33, 623/35, 622/381, 623/242, 165/135, 165/185, 252/62.51 R, 252/62.55
• US Class Current: 1/1
• CPC Class Codes: F25B 21/00 Machines, plants or systems, using electric or magnetic effects
• CPC Class Codes: F25B 2321/002 by using magneto-caloric effects
• CPC Class Codes: H01F 1/015 Metals or alloys

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.

Claims

1. 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 magnetocaloric cascade 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 magnetocaloric cascade 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 magnetocaloric cascade 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 magnetocaloric cascade according to claim 1, wherein the layer performance Lp of each of the 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 magnetocaloric cascade 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 magnetocaloric cascade 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 magnetocaloric cascade according to claim 1, wherein the magnetocaloric cascade comprises 3 to 100 different magnetocaloric materials having different Curie temperatures.

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

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

11. The magnetocaloric cascade 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 magnetocaloric cascade according to claim 1, wherein the magnetocaloric materials are selected from

(1) compounds of the general formula (I)

(A_yB₁₋

y)_2+dC_wD_xE_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_xAl<sub>1−

x</sub>)₁₃H_y or La(Fe_xSi<sub>1−

x</sub>)₁₃H_y  

 

(II)

where

x is a number from 0.7 to 0.95,

y is a number from 0 to 3;

La(Fe_xAl_yCo_z)₁₃ or La(Fe_xSi_yCo_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_xFe<sub>2−

x</sub>Ge  

 

(IV)

where

x is a number from 1.7 to 1.95;

(3) Heusler alloys of a MnT_tT_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)

Gd₅(Si_xGe<sub>1−

x</sub>)₄  

 

(V)

where x is a number from 0.2 to 1;

(5) Fe₂P-based compounds;

(6) manganites of a perovskite type;

(7) compounds that comprise rare earth elements and are of the general formulae (VI) and (VII)

Tb₅(Si<sub>4−

x</sub>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<sub>2−

x</sub>Z_xSb  

 

(VIII) and

Mn₂Z_xSb<sub>1−

x</sub>  

 

(IX)

where

Z is Cr, Cu, Zn, Co, V, As, Ge,

x is from 0.01 to 0.5;

Mn<sub>2−

x</sub>Z_xAs  

 

(X) and

Mn₂Z_xAs<sub>1−

x</sub>  

 

(XI)

where

Z is Cr, Cu, Zn, Co, V, Sb, Ge,

x is from 0.01 to 0.5.

13. The magnetocaloric cascade 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 magnetocaloric cascade according to claim 1, which comprises the process comprising:

shaping subjecting powders a powder of each particular magnetocaloric materials to shaping material to form each magnetocaloric material, and

subsequently packing the magnetocaloric materials to form the magnetocaloric cascade.