Counterflow thermoelectric configuration employing thermal transfer fluid in closed cycle

• US 7,293,416 B2
• Filed: 12/23/2004
• Issued: 11/13/2007
• Est. Priority Date: 12/23/2004
• Status: Active Grant

• Current Assignee: Sheetak, Inc.
• Original Assignee: Nanocoolers, Inc.
• Inventors: Ghoshal, Uttam
• Primary Examiner(s): Jones; Melvin
• Application Number:
  US11/020,355
• Publication Number:
  US 20060137359A1
• Time in Patent Office: 1,055 Days
• Field of Search: 62/32, 62/36, 62/37, 622/591
• US Class Current: 62/3.7
• CPC Class Codes: F25B 21/02 using Peltier effect; using Nernst-Ettinghausen effect
• CPC Class Codes: F25B 2321/0252 by liquids or two-phase fluids
• CPC Class Codes: F25B 25/005 using primary and secondary systems
• CPC Class Codes: H10N 10/13 characterised by the heat-exchanging means at the junction
• CPC Class Codes: H10N 10/17 characterised by the structure or configuration of the cell or thermocouple forming the device

Abstract

Active cooling technologies such as thermoelectrics can be used to introduce thermal “gain” into a cooling system and, when employed in combination with forced flow liquid metal cooling loops, can provide an attractive solution for cooling high heat flux density devices and/or components. Total cooling power can be increased by employing multiple thermoelectric elements. Indeed, by employing modern semiconductor technologies, including e.g., thin-film technologies, thermoelectric elements may be cost-effectively employed and configured in large arrays.

Claims

1. A thermoelectric system comprising:

plural thermoelectric modules, each including at least one thermoelectric element and together defining a thermoelectric array, individual ones of the thermoelectric elements having respective first and second sides and exhibiting respective thermal differentials during operation;

a first closed fluid loop pathway portion in thermal communication with the first sides of the thermoelectric elements; and

a second closed fluid loop pathway portion in thermal communication with the second sides of the thermoelectric elements,

wherein a counterflow topology of the first and second closed fluid loop pathway portions is structured to ensure that the respective thermal differentials are substantially uniform during operation with a thermal transfer fluid.

2. The thermoelectric system of claim 1, further comprising:

the thermal transfer fluid disposed within at least one of the first and second closed fluid loop pathway portions.

3. The thermoelectric system of claim 2,

wherein the thermal transfer fluid includes one or more of a liquid metal, a conductive fluid, and a conductive slurry.

4. The thermoelectric system of claim 1, further comprising:

at least one electromagnetic pump to motivate flow of the thermal transfer fluid through one or both of the first and second closed fluid loop pathway portions.

5. The thermoelectric system of claim 1,

wherein the first and second closed fluid loop pathway portions are each part of a respective closed fluid loop for transfer of the thermal transfer fluid away from, and back to, the thermoelectric array.

6. The thermoelectric system of claim 1, further comprising:

two distinct closed fluid loops for transfer of the thermal transfer fluid away from, and back to, the thermoelectric array,

the first closed fluid loop including the first closed fluid loop pathway portion and in thermal communication with the first sides of the thermoelectric elements and

the second closed fluid loop including the second closed fluid loop pathway portion and in thermal communication with the second sides of the thermoelectric elements.

7. The thermoelectric system of claim 6, further comprising,

at least one electromagnetic pump to motivate flow of a liquid metal thermal transfer fluid through the first closed fluid loop pathway portion.

8. The thermoelectric system of claim 7, further comprising,

at least one electromagnetic pump to motivate flow of a liquid metal thermal transfer fluid through the second closed fluid loop pathway portion.

9. The thermoelectric system of claim 1, further comprising:

a single closed loop in thermal communication with both the first and second sides of the thermoelectric elements,

the single closed fluid loop including both the first and the second closed fluid loop pathway portions.

10. The thermoelectric system of claim 9,

wherein a single electromagnetic pump is disposed within the single closed loop to motivate flow of a liquid metal thermal transfer fluid through both the first and second closed fluid loop pathway portions.

11. The thermoelectric system of claim 1, further comprising:

two at least partially overlapped closed fluid loops for transfer of the thermal transfer fluid away from, and back to, the thermoelectric array,

the first closed fluid loop including the first closed fluid loop pathway portion and in thermal communication with the first sides of the thermoelectric elements and

the second closed fluid loop including the second closed fluid loop pathway portion and in thermal communication with the second sides of the thermoelectric elements,

wherein thermal transfer fluid from the first and second closed fluid loops is commingled at at least one point in the overlapped closed fluid loops.

12. The thermoelectric system of claim 11, further comprising:

at least one electromagnetic pump disposed in an overlapped portion of the overlapped closed fluid loops.

13. The thermoelectric system of claim 1,

wherein the flow topology traverses N-stages of the thermoelectric array, and

wherein the flow topology is structured so that, at any particular one of the thermoelectric modules, impinging hot-side and cold-side flows respectively traverse x and N-1-x stages {x:

0≦

x<

N} enroute to the particular thermoelectric module.

14. The thermoelectric system of claim 4,

wherein the at least one electromagnetic pump includes a magnetofluiddynamic (MFD) pump.

15. The thermoelectric system of claim 4,

wherein the at least one electromagnetic pump is continuously operable.

16. The thermoelectric system of claim 4,

wherein the at least one electromagnetic pump is operable periodically or intermittently.

17. The thermoelectric system of claim 1, further comprising:

a recuperator that substantially equilibrates temperature of the thermal transfer fluid entering the first and second closed fluid loop pathway portions.

18. The thermoelectric system of claim 17,

wherein the recuperator commingles fluid flows.

19. The thermoelectric system of claim 17,

wherein the recuperator includes a heat exchanger.

20. The thermoelectric system of claim 1,

wherein a first formulation of the thermal transfer fluid is disposed within the first closed fluid loop pathway portion;

and

wherein a second formulation of the thermal transfer fluid is disposed within the second closed fluid loop pathway portion.

21. The thermoelectric system of claim 20,

wherein the first and second formulations are different formulations.

22. The thermoelectric system of claim 20,

wherein the first and second formulations are substantially identical formulations.

23. The thermoelectric system of claim 1, configured to perform one or more of the following:

cool a heat source or target;

heat a target;

at least partially regulate temperature of a heat source or target; and

generate current flow in response to a temperature differential.

24. The thermoelectric system of claim 1, further comprising:

a closed fluid loop including one or both of first and second closed fluid loop pathway portions.

25. The thermoelectric system of claim 24, further comprising either or both of:

a heat sink in thermal communication with the closed fluid loop; and

a heat source or target in thermal communication with the closed fluid loop.

26. The thermoelectric system of claim 1, wherein the thermoelectric array includes:

a linear array;

or

a 2-dimensional array.

27. A thermoelectric array configuration that that motivates flow of a liquid metal thermal transfer fluid in a first closed fluid loop using a magnetofluiddynamic (MFD) pump, wherein the motivated flow is part of a counterflow topology structured to ensure that thermal differentials across modules of the thermoelectric array are substantially uniform during operation.

28. The thermoelectric array configuration of claim 27,

wherein the first closed fluid loop is in thermal communication with first sides of the modules.

29. The thermoelectric array configuration of claim 28, further comprising:

a second closed fluid loop distinct from the first closed fluid loop, wherein the second closed fluid loop is in thermal communication with second sides of the modules.

30. The thermoelectric array configuration of claim 29, further comprising,

at least one additional MFD pump to motivate flow of the liquid metal thermal transfer fluid through the second closed fluid loop.

31. The thermoelectric array configuration of claim 28, further comprising:

a second closed fluid loop partially overlapped with the first closed fluid loop, wherein the second closed fluid loop is in thermal communication with second sides of the modules.

32. The thermoelectric array configuration of claim 31,

wherein liquid metal thermal transfer fluid from the first and second closed fluid loops is commingled at at least one point in an overlapped portion of the first and second closed fluid loops.

33. The thermoelectric array configuration of claim 31,

wherein the MFD pump is disposed in an overlapped portion of the first and second closed fluid loops.

34. The thermoelectric array configuration of claim 27,

wherein the first closed loop constitutes a single closed loop in thermal communication with both first and second sides of the modules.

35. The thermoelectric array configuration of claim 27,

wherein the flow topology traverses N modules of the thermoelectric array, and

wherein the flow topology is structured so that, at any particular one of the modules, impinging hot-side and cold-side flows respectively traverse x and N-1-x stages {x:

0≦

x<

N} enroute to the particular module.

36. The thermoelectric array configuration of claim 27, further comprising:

a recuperator that substantially equilibrates temperature of the liquid metal thermal transfer fluid entering the first and second closed fluid loop pathway portions that respectively traverse first and second sides of the modules.

37. The thermoelectric array configuration of claim 36,

wherein the recuperator commingles fluid flows.

38. The thermoelectric array configuration of claim 36,

wherein the recuperator includes a heat exchanger.

39. A method of operating a thermoelectric system that includes plural thermoelectric modules, each including at least one thermoelectric element and together defining a thermoelectric array, individual ones of the thermoelectric elements having respective first and second sides and exhibiting respective thermal differentials during operation, the method comprising:

motivating flow of a first thermal transfer fluid through a first closed fluid loop pathway portion in thermal communication with the first sides of the thermoelectric elements; and

motivating flow of a second thermal transfer fluid through a second closed fluid loop pathway portion in thermal communication with the second sides of the thermoelectric elements,

wherein topologies of the motivated flows are selected to achieve substantially uniformity of the thermal differentials during operation of the thermoelectric system.

40. The method of claim 39,

wherein the first and second closed fluid loops are distinct.

41. The method of claim 40,

wherein the motivating of respective flows of thermal transfer fluid through respective ones of the first and second closed fluid loops is by operation of respective first and second magnetofluiddynamic (MFD) pumps.

42. The method of claim 39,

wherein the first and second closed fluid loops constitute a single closed fluid loop;

and

wherein the first and second thermal transfer fluids are a same fluid.

43. The method of claim 42,

wherein the motivating of respective flows of thermal transfer fluid through the first and second closed fluid loops is by operation of a single magnetofluiddynamic (MFD) pump.

44. The method of claim 39,

wherein the second closed fluid loop is partially overlapped with the first closed fluid loop;

and

wherein the first and second thermal transfer fluids are a same fluid.

45. The method of claim 44, further comprising:

commingling the first and second thermal transfer fluids at at least one point in an overlapped portion of the first and second closed fluid loops.

46. The method of claim 44,

wherein the motivating of respective flows of thermal transfer fluid through the first and second closed fluid loops is by operation of at least one magnetofluiddynamic (MFD) pump disposed in an overlapped portion of the first and second closed fluid loops.

47. The method of claim 39, wherein the topologies of the motivated flows traverse N of the thermoelectric modules, the method further comprising:

traversing as part of a first side flow, x stages enroute to a particular module; and

traversing as part of a second side flow, N-1-x stages enroute to the particular module, wherein {x;

0≦

x<

N}.

48. The method of claim 39,

wherein the topologies of the motivated flows include counterflows.

49. The method of claim 39, further comprising:

substantially equilibrating temperature of thermal transfer fluid entering the first and second closed fluid loop pathway portions.

50. The method of claim 39, further comprising:

commingling thermal transfer fluid flows entering the first and second closed fluid loop pathway portions.

51. The method of claim 39, further comprising:

exchanging heat between thermal transfer fluid flows entering the first and second closed fluid loop pathway portions.

52. A method of making a thermoelectric system product, the method comprising:

providing plural thermoelectric modules, each including at least one thermoelectric element and together defining a thermoelectric array, individual ones of the thermoelectric elements having respective first and second sides;

configuring a first closed fluid loop pathway portion in thermal communication with the first sides of the thermoelectric elements;

configuring a second closed fluid loop pathway portion in thermal communication with the second sides of the thermoelectric elements; and

coupling an electromagnetic pump to at least one of the first and second closed fluid loop pathway portions.

53. A method of making a thermoelectric system product as recited in claim 52, the method further comprising:

closing a first closed fluid loop including one of the first and second closed fluid loop pathway portions.

54. A method of making a thermoelectric system product as recited in claim 52, the method further comprising:

closing a single closed fluid loop including both the first and second closed fluid loop pathway portions.

55. A method of making a thermoelectric system product as recited in claim 52, the method further comprising:

closing at least a first one of two partially overlapped closed fluid loops, the first closed fluid loop including one of the first and second closed fluid loop pathway portions.

56. A method of making a thermoelectric system product as recited in claim 52, the method further comprising:

introducing a thermal transfer fluid into a closed fluid loop that includes one or both of the first and second closed fluid loop pathway portions.

57. A method of making a thermoelectric system product as recited in claim 52,

wherein the providing includes providing N of the thermoelectric modules;

and

wherein the configuring of first and second closed fluid pathway portions includes

causing the first closed fluid pathway portion to traverse x of the thermoelectric modules enroute to any particular one of the thermoelectric modules; and

causing the second closed fluid pathway portion to traverse N-1-x of the thermoelectric modules enroute to the particular module, wherein {x0≦

x<

N}.

58. A method of making a thermoelectric system product as recited in claim 52,

wherein the configuring of first and second closed fluid pathway portions includes defining a counterflow topology.

59. A method of making a thermoelectric system product as recited in claim 52, the method further comprising:

positioning a recuperator to substantially equilibrate temperature of thermal transfer fluid destined for the first and second closed fluid loop pathway portions.

60. A method of making a thermoelectric system product as recited in claim 52, the method further comprising:

thermally coupling a closed fluid loop to a heat source, the closed fluid loop including one or both of the first and second closed fluid loop pathway portions.

61. A method of making a thermoelectric system product as recited in claim 52, the method further comprising:

thermally coupling a closed fluid loop to a heat sink, the closed fluid loop including one or both of the first and second closed fluid loop pathway portions.

62. A method of making a thermoelectric system product as recited in claim 52, the method further comprising:

thermally coupling a closed fluid loop to a thermal regulation target, the closed fluid loop including one or both of the first and second closed fluid loop pathway portions.

63. An apparatus comprising:

plural thermoelectric modules, each including at least one thermoelectric element and together defining a thermoelectric array;

means for motivating flow of an electrically-conductive thermal transfer fluid away from, or back to, the thermoelectric array; and

means for defining a flow topology that ensures that respective thermal differentials across modules of the thermoelectric array are substantially uniform during operation.

64. The apparatus of claim 63, further comprising:

means for guiding flow of the electrically-conductive thermal transfer fluid in at least one closed fluid cycle.

65. The apparatus of claim 63, further comprising:

means for exchanging thermal energy between the electrically-conductive thermal transfer fluid and a heat source, target or sink.

66. The apparatus of claim 63, further comprising:

means for substantially equilibrating temperature of the electrically-conductive thermal transfer fluid destined for respective sides of the thermoelectric array.