U.S. patent application number 10/698179 was filed with the patent office on 2004-06-17 for method and apparatus for efficient vertical fluid delivery for cooling a heat producing device.
This patent application is currently assigned to Cooligy, Inc.. Invention is credited to Corbin, Dave, Goodson, Kenneth, Hom, James, Kenny, Thomas W., Lovette, James, McMaster, Mark, Munch, Mark, Shook, James Gill, Upadhya, Girish, Zhou, Peng.
Application Number | 20040112571 10/698179 |
Document ID | / |
Family ID | 37741531 |
Filed Date | 2004-06-17 |
United States Patent
Application |
20040112571 |
Kind Code |
A1 |
Kenny, Thomas W. ; et
al. |
June 17, 2004 |
Method and apparatus for efficient vertical fluid delivery for
cooling a heat producing device
Abstract
A method and apparatus for cooling a hat source configured along
a lane. The heat exchanger comprises an interface layer that
perform thermal exchanger with the heat source and configured to
pass fluid from a first side to a second side. The manifold layer
comprises a first layer in contact with the heat source and has an
appropriate thermal conductivity to pass heat to the interface
layer. The manifold layer further comprises a second layer couple
to the first layer and in contact with the second side of the
interface layer. The first layer comprises a recess area having a
heat conducting region in contact with the heat exchanging layer.
The first layer includes at least one inlet and/or outlet port. The
second layer includes at least one inlet and/or outlet port. At
least one inlet and/or outlet port is positioned substantially
parallel or perpendicular with respect to the plane.
Inventors: |
Kenny, Thomas W.; (San
Carlos, CA) ; Munch, Mark; (Los Altos, CA) ;
Zhou, Peng; (Albany, CA) ; Shook, James Gill;
(Santa Cruz, CA) ; Upadhya, Girish; (San Jose,
CA) ; Goodson, Kenneth; (Belmont, CA) ;
Corbin, Dave; (Los Altos, CA) ; McMaster, Mark;
(Menlo Park, CA) ; Lovette, James; (San Francisco,
CA) ; Hom, James; (Redwood City, CA) |
Correspondence
Address: |
HAVERSTOCK & OWENS LLP
162 NORTH WOLFE ROAD
SUNNYVALE
CA
94086
US
|
Assignee: |
Cooligy, Inc.
|
Family ID: |
37741531 |
Appl. No.: |
10/698179 |
Filed: |
October 30, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10698179 |
Oct 30, 2003 |
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10680584 |
Oct 6, 2003 |
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10680584 |
Oct 6, 2003 |
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10439635 |
May 16, 2003 |
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60423009 |
Nov 1, 2002 |
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60442383 |
Jan 24, 2003 |
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60455729 |
Mar 17, 2003 |
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Current U.S.
Class: |
165/80.3 ;
165/133; 165/905; 257/E23.098; 257/E23.1 |
Current CPC
Class: |
F04B 17/00 20130101;
F25B 21/02 20130101; F28F 3/02 20130101; H01L 23/4735 20130101;
H01L 2924/0002 20130101; F28F 3/12 20130101; H01L 2924/00 20130101;
H01L 23/38 20130101; H01L 35/30 20130101; F28F 3/086 20130101; F28D
2021/0029 20130101; F28F 13/06 20130101; F04B 19/006 20130101; G06F
2200/201 20130101; F28D 15/0266 20130101; F28F 2210/10 20130101;
F28D 21/0015 20130101; G06Q 20/20 20130101; H01L 23/473 20130101;
H01L 2924/0002 20130101; F28F 13/185 20130101; F28D 15/00 20130101;
F25B 2321/0252 20130101; G06F 1/20 20130101 |
Class at
Publication: |
165/080.3 ;
165/133; 165/905 |
International
Class: |
F28F 007/00; F28F
013/18; F28F 019/02 |
Claims
What is claimed is:
1. A heat exchanger comprising: a body having a conducting portion
in contact with a heat source configured along a plane, wherein the
conducting portion conducts heat from the heat source to a heat
exchanging layer configured within the body, the body including at
least one inlet port and at least one outlet port, wherein the at
least one inlet port channels fluid through the heat exchanging
layer from a first side proximal to the conducting portion to a
second side distal to the conducting portion.
2. The heat exchanger according to claim 1 wherein the body further
comprises: a. a first layer having the conducting portion and
configured to pass fluid therealong from the at least one inlet
port; and b. a second layer coupled to the first layer, wherein the
heat exchanging layer is configured between the first layer and the
second layer.
3. The heat exchanger according to claim 2 wherein the first layer
further comprises a recess area having a heat conducting region in
contact with the heat exchanging layer.
4. The heat exchanger according to claim 2 wherein the first layer
includes the at least one inlet port.
5. The heat exchanger according to claim 2 wherein the first layer
includes the at least one outlet port.
6. The heat exchanger according to claim 2 wherein the second layer
includes the at least one inlet port.
7. The heat exchanger according to claim 2 wherein the second layer
includes the at least one outlet port.
8. The heat exchanger according to claim 1 wherein the at least one
inlet port is positioned substantially parallel with respect to the
plane.
9. The heat exchanger according to claim 1 wherein the at least one
inlet port is positioned substantially perpendicular with respect
to the plane.
10. The heat exchanger according to claim 1 wherein the at least
one outlet port is positioned substantially parallel with respect
to the plane.
11. The heat exchanger according to claim 1 wherein the at least
one outlet port is positioned substantially perpendicular with
respect to the plane.
12. The heat exchanger according to claim 8 wherein the recess area
includes a plurality of fluid inlet grooves through in the heat
conducting area, the fluid inlet grooves for channeling fluid from
the at least one inlet port to the heat exchanging layer.
13. The heat exchanger according to. claim 8 wherein the second
layer further comprises a plurality of fluid outlet grooves for
channeling fluid from the heat exchanging layer to the second
port.
14. The heat exchanger according to claim 1 wherein the fluid is in
single phase flow conditions.
15. The heat exchanger according to claim 1 wherein at least a
portion of the fluid is in two phase flow conditions.
16. The heat exchanger according to claim 1 wherein the conducting
portion has a thickness dimension within the range of and including
0.3 to 0.7 millimeters.
17. The heat exchanger according to claim 1 wherein an overhang
dimension is within the range of and including 0 to 15
millimeters.
18. The heat exchanger according to claim 1 wherein at least a
portion of the fluid undergoes a transition between single and two
phase flow conditions in the heat exchanger.
19. The heat exchanger according to claim 2 wherein the first layer
is made of a material having a thermal conductivity of at least 100
W/mK.
20. The heat exchanger according to claim 2 wherein the first layer
further comprises a plurality of pillars configured in a
predetermined pattern along the interface layer.
21. The heat exchanger according to claim 20 wherein at least one
of the plurality of pillars has an area dimension within the range
of and including (10 micron).sup.2 and (100 micron).sup.2.
22. The heat exchanger according to claim 20 wherein at least one
of the plurality of pillars has a height dimension within the range
of and including 50 microns and 2 millimeters.
23. The heat exchanger according to claim 20 wherein at least two
of the plurality of pillars are separate from each other by a
spacing dimension within the range of and including 10 to 150
microns.
24. The heat exchanger according to claim 20 wherein at least one
of the plurality of pillars includes at least varying dimension
along a predetermined direction.
25. The heat exchanger according to claim 20 wherein an appropriate
number of pillars are disposed in a predetermined area along the
interface layer.
26. The heat exchanger according to claim 1 wherein at least a
portion of the first layer has a roughened surface.
27. The heat exchanger according to claim 20 wherein the plurality
of pillars include a coating thereupon, wherein the coating has an
appropriate thermal conductivity of at least 10 W/m-K.
28. The heat exchanger according to claim 1 wherein the heat
exchanging layer is made of a porous microstructure.
29. The heat exchanger according to claim 28 wherein the porous
microstructure has a porosity within the range of and including 50
to 80 percent.
30. The heat exchanger according to claim 28 wherein the porous
microstructure has an average pore size within the range of and
including 10 to 200 microns.
31. The heat exchanger according to claim 28 wherein the porous
microstructure has a height dimension within the range of and
including 0.25 to 2.00 millimeters.
32. The heat exchanger according to claim 28 wherein the porous
microstructure includes at least one pore having a varying
dimension along a predetermined direction.
33. The heat exchanger according to claim 1 further comprising a
plurality of microchannels disposed in a predetermined
configuration along the first layer.
34. The heat exchanger according to claim 33 wherein at least one
of the plurality of microchannels has an area dimension within the
range of and including (10 micron).sup.2 and (100
micron).sup.2.
35. The heat exchanger according to claim 33 wherein at least one
of the plurality of microchannels has a height dimension within the
range of and including 50 microns and 2 millimeters.
36. The heat exchanger according to claim 33 wherein at least two
of the plurality of microchannels are separate from each other by a
spacing dimension within the range of and including 10 to 150
microns.
37. The heat exchanger according to claim 33 wherein at least one
of the plurality of microchannels has a width dimension within the
range of and including 10 to 100 microns.
38. The heat exchanger according to claim 1 wherein the first layer
is coupled to the heat source.
39. The heat exchanger according to claim 1 wherein the first layer
is integrally formed to the heat source.
40. The heat exchanger according to claim 1 wherein the heat source
is an integrated circuit.
41. The heat exchanger according to claim 1 further comprising a
thermoelectric device positioned between the conducting portion and
the heat source, wherein the thermoelectric device is electrically
coupled to a power source.
42. The heat exchanger according to claim 41 wherein the
thermoelectric device is integrally formed within the heat
exchanger.
43. The heat exchanger according to claim 41 wherein the
thermoelectric device is integrally formed within the heat
source.
44. The heat exchanger according to claim 41 wherein the
thermoelectric device is coupled to the heat exchanger and the heat
source.
45. A heat exchanger configured to cool a heat source configured
along a plane comprising: a. an interface layer for performing
thermal exchange with the heat source and configured to pass fluid
from a first side to a second side; and b. a manifold layer
comprising: i. a first layer in contact with the heat source and
having an appropriate thermal conductivity to pass heat to the
first side of the interface layer; and ii. a second layer coupled
to the first layer and in contact with the second side of the
interface layer.
46. The heat exchanger according to claim 45 wherein the first
layer further comprises a recess area having a heat conducting
region in contact with the interface layer.
47. The heat exchanger according to claim 45 wherein the first
layer includes the at least one inlet port.
48. The heat exchanger according to claim 45 wherein the first
layer includes the at least one outlet port.
49. The heat exchanger according to claim 45 wherein the second
layer includes the at least one inlet port.
50. The heat exchanger according to claim 45 wherein the second
layer includes the at least one outlet port.
51. The heat exchanger according to claim 45 wherein the at least
one inlet port is positioned substantially parallel with respect to
the plane.
52. The heat exchanger according to claim 45 wherein the at least
one inlet port is positioned substantially perpendicular with
respect to the plane.
53. The heat exchanger according to claim 45 wherein the at least
one outlet port is positioned substantially parallel with respect
to the plane.
54. The heat exchanger according to claim 45 wherein the at least
one outlet port is positioned substantially perpendicular with
respect to the plane.
55. The heat exchanger according to claim 46 wherein the recess
area includes a plurality of fluid inlet grooves through in the
heat conducting region, the fluid inlet grooves for channeling
fluid from at least one inlet port to the interface layer.
56. The heat exchanger according to claim 45 wherein the second
layer further comprises a plurality of fluid outlet grooves for
channeling fluid from the interface layer to at least one outlet
port.
57. The heat exchanger according to claim 45 wherein the fluid is
in single phase flow conditions.
58. The heat exchanger according to claim 45 wherein at least a
portion of the fluid is in two phase flow conditions.
59. The heat exchanger according to claim 45 wherein the first
layer has a thickness dimension within the range of and including
0.3 to 0.7 millimeters.
60. The heat exchanger according to claim 45 wherein an overhang
dimension is within the range of and including 0 to 15
millimeters.
61. The heat exchanger according to claim 45 wherein at least a
portion of the fluid undergoes a transition between single and two
phase flow conditions in the heat exchanger.
62. The heat exchanger according to claim 45 wherein the thermal
conductivity is at least 100 W/m-K.
63. The heat exchanger according to claim 45 wherein the first
layer further comprises a plurality of pillars configured in a
predetermined pattern along the first layer.
64. The heat exchanger according to claim 63 wherein at least one
of the plurality of pillars has an area dimension within the range
of and including (10 micron).sup.2 and (100 micron).sup.2.
65. The heat exchanger according to claim 63 wherein at least one
of the plurality of pillars has a height dimension within the range
of and including 50 microns and 2 millimeters.
66. The heat exchanger according to claim 63 wherein at least two
of the plurality of pillars are separate from each other by a
spacing dimension within the range of and including 10 to 150
microns.
67. The heat exchanger according to claim 63 wherein at least one
of the plurality of pillars includes at least varying dimension
along a predetermined direction.
68. The heat exchanger according to claim 63 wherein an appropriate
number of pillars are disposed in a predetermined area along the
interface layer.
69. The heat exchanger according to claim 45 wherein at least a
portion of the first layer has a roughened surface.
70. The heat exchanger according to claim 63 wherein the plurality
of pillars include a coating thereupon, wherein the coating has an
appropriate thermal conductivity of at least 10 W/m-K.
71. The heat exchanger according to claim 45 wherein the interface
layer is made of a porous microstructure.
72. The heat exchanger according to claim 71 wherein the porous
microstructure has a porosity within the range of and including 50
to 80 percent.
73. The heat exchanger according to claim 71 wherein the porous
microstructure has an average pore size within the range of and
including 10 to 200 microns.
74. The heat exchanger according to claim 71 wherein the porous
microstructure has a height dimension within the range of and
including 0.25 to 2.00 millimeters.
75. The heat exchanger according to claim 71 wherein the porous
microstructure includes at least one pore having a varying
dimension along a predetermined direction.
76. The heat exchanger according to claim 45 further comprising a
plurality of microchannels disposed in a predetermined
configuration along the first layer.
77. The heat exchanger according to claim 76 wherein at least one
of the plurality of microchannels has an area dimension within the
range of and including (10 micron).sup.2 and (100
micron).sup.2.
78. The heat exchanger according to claim 76 wherein at least one
of the plurality of microchannels has a height dimension within the
range of and including 50 microns and 2 millimeters.
79. The heat exchanger according to claim 76 wherein at least two
of the plurality of microchannels are separate from each other by a
spacing dimension within the range of and including 10 to 150
microns.
80. The heat exchanger according to claim 76 wherein at least one
of the plurality of microchannels has a width dimension within the
range of and including 10 to 100 microns.
81. The heat exchanger according to claim 45 wherein the first
layer is coupled to the heat source.
82. The heat exchanger according to claim 45 wherein the first
layer is integrally formed to the heat source.
83. The heat exchanger according to claim 45 wherein the heat
source is an integrated circuit.
84. The heat exchanger according to claim 45 further comprising a
thermoelectric device positioned between the first layer and the
heat source, wherein the thermoelectric device is electrically
coupled to a power source.
85. The heat exchanger according to claim 84 wherein the
thermoelectric device is integrally formed within the heat
exchanger.
86. The heat exchanger according to claim 84 wherein the
thermoelectric device is integrally formed within the heat
source.
87. The heat exchanger according to claim 84 wherein the
thermoelectric device is coupled to the heat exchanger and the heat
source.
88. A method of manufacturing a heat exchanger configured to cool a
heat source positioned along a plane, the method comprising the
steps of: a. providing a first layer configurable to be in contact
with the heat source and to pass fluid along a heat conducting
surface; b. coupling a second layer to the first layer, wherein a
first side of the second layer is in contact with the heat
conducting surface and configured to pass fluid from the first
layer therethrough; and c. coupling a third layer to the first and
second layers, wherein a second side of the second layer is in
contact with the third layer.
89. The method of manufacturing according to claim 88 wherein the
first layer further comprises a recess area having the heat
conducting surface.
90. The method of manufacturing according to claim 88 wherein the
heat exchanger includes at least one inlet port for channeling
fluid to the first side and at least one outlet port for channeling
fluid from the second side.
91. The method of manufacturing according to claim 90 wherein the
first layer includes the at least one inlet port.
92. The method of manufacturing according to claim 90 wherein the
first layer includes the at least one outlet port.
93. The method of manufacturing according to claim 90 wherein the
third layer includes the at least one inlet port.
94. The method of manufacturing according to claim 90 wherein the
third layer includes the at least one outlet port.
95. The method of manufacturing according to claim 90 wherein the
at least one inlet port is positioned substantially parallel with
respect to the plane.
96. The method of manufacturing according to claim 90 wherein the
at least one inlet port is positioned substantially perpendicular
with respect to the plane.
97. The method of manufacturing according to claim 90 wherein the
at least one outlet port is positioned substantially parallel with
respect to the plane.
98. The method of manufacturing according to claim 90 wherein the
at least one outlet port is positioned substantially perpendicular
with respect to the plane.
99. The method of manufacturing according to claim 89 wherein the
recess area includes a plurality of fluid inlet grooves along the
heat conducting surface, the fluid inlet grooves for channeling
fluid from at least one inlet port to the second layer.
100. The method of manufacturing according to claim 88 wherein the
fluid is in single phase flow conditions.
101. The method of manufacturing according to claim 88 wherein at
least a portion of the fluid is in two phase flow conditions.
102. The method of manufacturing according to claim 88 wherein the
first layer has a thickness dimension within the range of and
including 0.3 to 0.7 millimeters.
103. The method of manufacturing according to claim 88 wherein an
overhang dimension is within the range of and including 0 to 15
millimeters.
104. The method of manufacturing according to claim 88 wherein at
least a portion of the fluid undergoes a transition between single
and two phase flow conditions in the heat exchanger.
105. The method of manufacturing according to claim 88 wherein the
first layer is made of a material having a thermal conductivity of
at least 100 W/m-K.
106. The method of manufacturing according to claim 88 further
comprising forming a plurality of pillars in a predetermined
pattern along the interface layer.
107. The method of manufacturing according to claim 106 wherein at
least one of the plurality of pillars has an area dimension within
the range of and including (10 micron).sup.2 and (100
micron).sup.2.
108. The method of manufacturing according to claim 106 wherein at
least one of the plurality of pillars has a height dimension within
the range of and including 50 microns and 2 millimeters.
109. The method of manufacturing according to claim 106 wherein at
least two of the plurality of pillars are separate from each other
by a spacing dimension within the range of and including 10 to 150
microns.
110. The method of manufacturing according to claim 106 wherein at
least one of the plurality of pillars includes at least varying
dimension along a predetermined direction.
111. The method of manufacturing according to claim 88 further
comprising configuring at least a portion of the interface layer to
have a roughened surface.
112. The method of manufacturing according to claim 88 wherein the
second layer is made of a micro-porous structure.
113. The method of manufacturing according to claim 112 wherein the
porous microstructure has a porosity within the range of and
including 50 to 80 percent.
114. The method of manufacturing according to claim 112 wherein the
porous microstructure has an average pore size within the range of
and including 10 to 200 microns.
115. The method of manufacturing according to claim 112 wherein the
porous microstructure has a height dimension within the range of
and including 0.25 to 2.00 millimeters.
116. The method of manufacturing according to claim 88 further
comprising forming a plurality of microchannels onto the first
layer.
117. The method of manufacturing according to claim 116 wherein at
least one of the plurality of microchannels has an area dimension
within the range of and including (10 micron).sup.2 and (100
micron).sup.2.
118. The method of manufacturing according to claim 116 wherein at
least one of the plurality of microchannels has a height dimension
within the range of and including 50 microns and 2 millimeters.
119. The method of manufacturing according to claim 116 wherein at
least two of the plurality of microchannels are separate from each
other by a spacing dimension within the range of and including 10
to 150 microns.
120. The method of manufacturing according to claim 116 wherein at
least one of the plurality of microchannels has a width dimension
within the range of and including 10 to 100 microns.
121. The method of manufacturing according to claim 88 wherein the
first layer is coupled to the heat source.
122. The method of manufacturing according to claim 88 wherein the
first layer is integrally formed to the heat source.
123. The method of manufacturing according to claim 88 wherein the
heat source is an integrated circuit.
124. The method of manufacturing according to claim 88 further
comprising configuring a thermoelectric device between the first
layer and the heat source, wherein the thermoelectric device is
electrically coupled to a power source.
125. The method of manufacturing according to claim 124 wherein the
thermoelectric device is integrally formed within the heat
exchanger.
126. The method of manufacturing according to claim 124 wherein the
thermoelectric device is integrally formed within the heat
source.
127. The-method of manufacturing according to claim 124 wherein the
thermoelectric device is coupled to the heat exchanger and the heat
source.
Description
RELATED APPLICATIONS
[0001] This patent application is a continuation in part of U.S.
patent application Ser. No. 10/680,584, filed Oct. 6, 2003, and
entitled, "METHOD AND APPARATUS FOR EFFICIENT VERTICAL FLUID
DELIVERY FOR COOLING A HEAT PRODUCING DEVICE", hereby incorporated
by reference, which is a continuation in part of U.S. patent
application Ser. No. 10/439,635, filed May 16, 2003 and entitled,
"METHOD AND APPARATUS FOR FLEXIBLE FLUID DELIVERY FOR COOLING
DESIRED HOT SPOTS IN A BEAT PRODUCING DEVICE", hereby incorporated
by reference, which claims priority under 35 U.S.C. 119 (e) of the
now abandoned U.S. Provisional Patent Application, Serial No.
60/423,009, filed Nov. 1, 2002 and entitled, "METHODS FOR FLEXIBLE
FLUID DELIVERY AND HOTSPOT COOLING BY MICROCHANNEL HEAT SINKS",
hereby incorporated by reference, as well as now abandoned U.S.
Provisional Patent Application, Serial No. 60/442,383, filed Jan.
24,2003 and entitled, "OPTIMIZED PLATE FIN HEAT EXCHANGER FOR CPU
COOLING", which is also hereby incorporated by reference and
co-pending U.S. Provisional Patent Application, Serial No.
60/455,729, filed Mar. 17, 2003 and entitled, "MICROCHANNEL HEAT
EXCHANGER APPARATUS WITH POROUS CONFIGURATION AND METHOD OF
MANUFACTURING THEREOF", which is hereby incorporated by reference.
The U.S. patent application Ser. No. 10/439,635, filed May 16, 2003
and entitled, "METHOD AND APPARATUS FOR FLEXIBLE FLUID DELIVERY FOR
COOLING DESIRED HOT SPOTS IN A HEAT PRODUCING DEVICE" also claims
priority under 35 U.S.C. 119 (e) of the now abandoned U.S.
Provisional Patent Application, Serial No. 60/423,009, filed Nov.
1, 2002 and entitled, "METHODS FOR FLEXIBLE FLUID DELIVERY AND
HOTSPOT COOLING BY MICROCHANNEL HEAT SINKS", hereby incorporated by
reference, as well as co-pending U.S. Provisional Patent
Application, Serial No. 60/442,383, filed Jan. 24, 2003 and
entitled, "OPTIMIZED PLATE FIN HEAT EXCHANGER FOR CPU COOLING",
hereby incorporated by reference, and co-pending U.S. Provisional
Patent Application, Serial No. 60/455,729, filed Mar. 17, 2003 and
entitled, "MICROCHANNEL HEAT EXCHANGER APPARATUS WITH POROUS
CONFIGURATION AND METHOD OF MANUFACTURING THEREOF", which is hereby
incorporated by reference.
FIELD OF THE INVENTION
[0002] The invention relates to a method and apparatus for cooling
a heat producing device in general, and specifically, to a method
and apparatus for efficient vertical fluid delivery in cooling an
electronic device with minimal pressure drop within the heat
exchanger.
BACKGROUND OF THE INVENTION
[0003] Since their introduction in the early 1980's, microchannel
heat sinks have shown much potential for high heat-flux cooling
applications and have been used in the industry. However, existing
microchannels include conventional parallel channel arrangements
which are not well suited for cooling heat producing devices which
have spatially-varying heat loads. Such heat producing devices have
areas which produce more heat than others. These hotter areas are
hereby designated as "hot spots" whereas the areas of the heat
source which do not produce as much heat are hereby termed, "warm
spots".
[0004] FIGS. 1A and 1B illustrate a side view and top view of a
prior art heat exchanger 10 which is coupled to an electronic
device 99, such as a microprocessor via a thermal interface
material 98. As shown in FIGS. 1A and 1B, fluid generally flows
from a single inlet port 12 and flows along the bottom surface 11
in between the parallel microchanneis 14, as shown by the arrows,
and exits through the outlet port 16. Although the heat exchanger
10 cools the electronic device 99, the fluid flows from the inlet
port 12 to the outlet port 16 in a uniform manner. In other words,
the fluid flows substantially uniformly along the entire bottom
surface 11 of the heat exchanger 10 and does not supply more fluid
to areas in the bottom surface 11 which correspond with hot spots
in the device 99. In addition, the temperature of liquid flowing
from the inlet generally increases as it flows along the bottom
surface 11 of the heat exchanger. Therefore, regions of the heat
source 99 which are downstream or near the outlet port 16 are not
supplied with cool fluid, but actually warmer fluid or two-phase
fluid which has already been heated upstream. In effect, the heated
fluid actually propagates the heat across the entire bottom surface
11 of the heat exchanger and region of the heat source 99, whereby
fluid near the outlet port 16 is so hot that it becomes ineffective
in cooling the heat source 99. This increase in heat causes
two-phase flow instabilities in which the boiling of fluid along
the bottom surface 11 forces fluid away from the areas where the
most heat is generated. In addition, the heat exchanger 10 having
only one inlet 12 and one outlet 16 forces fluid to travel along
the long parallel microchannels 14 in the bottom surface 11 for the
entire length of the heat exchanger 10, thereby creating a large
pressure drop due to the length the fluid must travel. The large
pressure drop formed in the heat exchanger 10 makes pumping fluid
to the heat exchanger 10 difficult and augments the
instabilities.
[0005] FIG. 1C illustrates a side view diagram of a prior art
multi-level heat exchanger 20. Fluid enters the multi-level heat
exchanger 20 through the port 22 and travels downward through
multiple jets 28 in the middle layer 26 to the bottom surface 27
and out port 24. In addition, the fluid traveling along the jets 28
does not uniformly flow down to the bottom surface 27. In addition,
the heat exchanger in FIG. 1C exhibits the same problems discussed
above with regard to the heat exchanger 10 in FIGS. 1A and 1B.
[0006] What is needed is a heat exchanger which is configured to
achieve a small pressure drop between the inlet and outlet fluid
ports while efficiently cooling the heat source. What is needed is
a microchannel heat exchanger which is configured to achieve proper
temperature uniformity in the heat source. What is also needed is a
heat exchanger which is configured to achieve proper temperature
uniformity in light of hot spots in the heat source.
SUMMARY OF THE INVENTION
[0007] In one aspect of the invention, a heat exchanger comprises
an interface layer which cools a heat source. The interface layer
is in contact with the heat source and is configured to pass fluid
therethrough. The heat exchanger also includes a manifold layer
that is coupled to the interface layer. The manifold layer further
comprises a first set of individualized holes for channeling fluid
to the interface layer and a second set of individualized holes for
channeling fluid from the interface layer. The manifold layer
further comprises a first port which provides fluid to the first
set of individualized holes and a second port which removes fluid
channeled from the second set of individualized holes. The first
set of holes and second set of holes are arranged to provide a
minimized fluid path distance between the first and second ports to
adequately cool the heat source. Each hole in the first set is
positioned a closest optimal distance to an adjacent hole in the
second set. Fluid flowing through the heat exchanger is in one or
two phase flow conditions or a combination thereof. The manifold
layer further comprises a circulation level which has the first and
second holes that extend therethrough. The circulation level is
coupled to the interface layer and is configured to separably
channel fluid to and from the interface layer via the first and
second set of holes. The first set and second set of holes each
include a cylindrical protrusion in communication therewith,
whereby each cylindrical protrusions extends substantially vertical
with respect to the circulation level. The manifold layer further
comprises a first level that is coupled to the circulation level
and the first port. The first level is configured to channel fluid
between the first port and the first set of holes. A second level
is coupled to the first level and the second port. The second level
is configured to channel fluid between the second port and the
second set of holes, wherein fluid channeled via the first level is
kept separate from the fluid channeled via the second level. The
first level further comprises a first corridor that is coupled to
the first port, wherein the first set of holes are in sealable
engagement with the first corridor. The first level further
comprises a second corridor that is coupled to the second port,
wherein the second set of holes are in sealable engagement with the
second corridor. The first set and second set of holes are
thermally insulated from one another to prevent heat transfer
therebetween. The first set and the second set of holes are
arranged in a uniform manner along at least one dimension of the
circulation level in one embodiment. The first set and second set
of holes are arranged in a non-uniform manner along at least one
dimension of the circulation level in another embodiment. The first
set and second set of holes are separately sealed from one another.
Alternatively, the first set and second set of holes are positioned
to cool at least one interface hot spot region in the heat source.
In one embodiment, at least one of the holes in the first set has a
first dimension that is substantially equivalent to a second
dimension of at least one hole in the second set. In another
embodiment, at least one of the first set holes has a first
dimension that is different than a second dimension of at least one
of the second set holes. The interface layer has a thermal
conductivity of at least 100 W/mK. The interface layer further
comprises a plurality of pillars which are configured in a
predetermined pattern along the interface layer. Alternatively, an
appropriate number of pillars are disposed in a predetermined area
along the interface layer. Alternatively, the pillars include a
coating thereupon, wherein the coating has an appropriate thermal
conductivity of at least 10 W/m-K. Alternatively, the interface
layer further comprises a porous microstructure disposed thereon.
Alternatively, the interface layer has a roughened surface.
Alternatively, a plurality of microchanhels are configured in an
appropriate configuration in the interface layer.
[0008] In another aspect of the invention, a heat exchanger is
configureable to be coupled to a heat source. The heat exchanger
comprises an interface layer that is coupled to the heat source and
configured to pass fluid therethrough. Thus, the fluid undergoes
thermal exchange with heat produced from the heat source. The heat
exchanger further comprises a manifold layer that is coupled to the
interface layer which has at least one fluid inlet port. The fluid
inlet port is coupled to a substantially vertical inlet fluid path
which delivers fluid to the interface layer. The heat exchanger
further comprises at least one fluid outlet port that is coupled to
a substantially vertical outlet fluid path which removes fluid from
the interface layer. The inlet and outlet fluid paths are arranged
an optimal minimum fluid travel distance apart from each other. The
manifold layer further comprises a circulation level that is
coupled to the interface layer. The circulation level has a
plurality of inlet apertures that extend vertically therethrough
for channeling fluid along the inlet fluid path to the interface
layer. The circulation level has a plurality of outlet apertures
which extend vertically therethrough for channeling fluid along the
outlet fluid path from the interface layer. The manifold layer
includes an inlet level that is coupled to the circulation level
and the inlet port. The inlet level is configured to channel fluid
from the inlet port to the inlet apertures. The manifold layer
includes an outlet level that is coupled to the circulation level
and the outlet port. The outlet level is configured to channel
fluid from the outlet apertures to the outlet port. Fluid that is
channeled via the inlet level flows separately from the fluid that
is channeled via the outlet level. The fluid path in the inlet
level further comprises a fluid corridor which horizontally
channels fluid from the inlet port to the inlet apertures. The
fluid path in the outlet level further comprises a fluid corridor
which horizontally channels fluid from the outlet apertures to the
outlet port. The inlet and outlet fluid apertures are individually
arranged in a uniform manner along at least one dimension in the
circulation level in one embodiment. The inlet and outlet fluid
apertures are arranged in a nonuniform manner along at least one
dimension in the circulation level in another embodiment. The inlet
and outlet fluid paths are separately sealed from one another. The
inlet and outlet apertures are alternatively arranged to cool at
least one interface hot spot cooling region in the heat source. In
one embodiment, at least one of the inlet apertures has an inlet
dimension that is substantially equivalent to an outlet dimension
of at least one outlet apertures. In another embodiment, at least
one of the inlet apertures has an inlet dimension different than an
outlet dimension of at least one of the outlet apertures. The
interface layer preferably has a thermal conductivity of at least
100 W/mK. The interface layer further comprises a plurality of
pillars disposed thereon in an appropriate pattern, wherein an
appropriate number of pillars are disposed in a predetermined area
along the interface layer. Alternatively, the interface layer has a
roughened surface. The plurality of pillars include a coating
thereupon, wherein the coating has an appropriate thermal
conductivity of at least 10 W/m-K. The interface layer
alternatively has a porous microstructure disposed thereupon. The
heat exchanger includes a plurality of cylindrical protrusions
which extend an appropriate height from the circulation level,
whereby each protrusion is in communication with the first set and
second set of apertures. The cylindrical protrusions are thermally
insulated to prevent heat transfer therebetween.
[0009] In yet another aspect of the present invention, a manifold
layer adapted to be coupled to an interface layer to form a
microchannel heat exchanger comprises an inlet port which provides
a first temperature fluid. The manifold layer also includes an
inlet fluid path in communication with the inlet port, whereby the
inlet fluid path is adapted to channel the first temperature fluid
to the interface layer. The manifold layer includes an outlet fluid
path adapted to remove a second temperature fluid from the
interface layer, whereby the first temperature fluid and the second
temperature fluid are kept separate in the manifold layer. The
manifold layer includes an outlet port which is in communication
with the outlet fluid path. The second temperature fluid exits the
manifold layer via the outlet port. Each inlet passage provides a
direct inlet flow path from the first port to the interface layer
and each outlet passage provides a direct outlet flow path from the
interface layer to the second port. The inlet and outlet passages
are arranged to minimize fluid flow distance therebetween. The
inlet and outlet passages are arranged in a uniform manner along at
least one dimension of the third layer. Alternatively, the inlet
and outlet passages are arranged in a non-uniform manner along at
least one dimension of the third layer. The inlet and outlet
passages are separately sealed from one another. The inlet and
outlet passages are alternatively positioned in the third layer to
cool at least one interface hot spot region in the heat source. At
least one of the inlet passages has an inlet dimension that is
substantially equivalent to an outlet dimension of at least one
outlet passages. Alternatively, at least one of the inlet passages
has an inlet dimension that is different than an outlet dimension
of at least one of the outlet passages. The manifold layer further
comprises a plurality of cylindrical protrusions that extend an
appropriate height from the circulation level, whereby each
protrusion is individually in communication with the inlet and
outlet passages. The cylindrical protrusions are also thermally
insulated to prevent heat transfer therebetween. The protrusions
which are in communication with the inlet passages are sealably
coupled to the fluid entry corridor and the protrusions which are
in communication with the outlet passages are sealably coupled to
the fluid exit corridor.
[0010] Another aspect of the invention includes a method of
manufacturing a heat exchanger which is configured to cool a heat
source. The method comprises the steps of forming an interface
layer which is configurable to be coupled to the heat source. The
interface layer to pass fluid therethrough to cool the heat source.
The method also comprises forming a manifold layer to include a
plurality of substantially vertical inlet fluid paths and a
plurality of substantially vertical outlet fluid paths. The inlet
and outlet fluid paths are arranged to channel fluid flow for an
optimal minimum distance therebetween along the interface layer.
The method also comprises coupling the manifold layer to the
interface layer. The method further comprises the steps of coupling
at least one inlet fluid port to the inlet fluid paths, wherein
fluid enters the heat exchanger via the inlet fluid port. The
method further comprises coupling at least one outlet fluid port to
the outlet fluid paths, wherein fluid exits the heat exchange via
the outlet fluid port. The step of forming the manifold layer
further comprises forming a circulation level which has a plurality
of inlet apertures that extend vertically therethrough to thee
interface layer, whereby the inlet apertures channel inlet fluid
through the inlet fluid paths. The circulation level also has a
plurality of outlet apertures that extend vertically therethrough
to the interface layer and channel outlet fluid through the outlet
fluid paths. The step of forming the manifold layer further
comprises forming an inlet level to channel fluid from the inlet
port to the inlet apertures via the inlet corridor. The step of
forming the manifold layer further comprises coupling the inlet
level to the circulation level, wherein the inlet apertures are
sealably coupled with the inlet corridor. The step of forming the
manifold layer further comprises forming an outlet level to channel
fluid from the outlet apertures to the outlet port via an outlet
corridor. The step of forming the manifold layer also includes
coupling the outlet level to the circulation level, wherein the
outlet apertures are sealably coupled to the outlet corridor. Fluid
channeled via the inlet level is kept separate from the fluid
channeled via the outlet level. The inlet and outlet fluid paths
are positioned to cool at least one interface hot spot region in
the heat source. The method further comprises the step of
insulating the fluid inlet paths and the fluid outlet paths in the
manifold layer to minimize heat transfer therebetween. The
interface layer has a thermal conductivity of at least 100 W/in-K.
The method alternatively includes the step of applying a thermally
conductive coating to the interface layer by an electroplating
process. The method further comprises forming a plurality of
pillars in a predetermined pattern along the interface layer.
Alternatively, the method of manufacturing further comprises
configuring the interface layer to have a roughened surface. The
method of manufacturing alternatively comprises configuring a
micro-porous structure disposed on the interface layer. The method
of manufacturing alternatively comprises forming a plurality of
microchannels onto the interface layer. The method alternatively
comprises the step of applying a thermally conductive coating to
the plurality of pillars. The plurality of pillars are
alternatively formed by an electroforming process, an etching
process such as a wet etching, plasma etching, photochemical
etching, chemical etching, and laser assisted chemical etching. The
electroforming process is alternatively performed in combination
with a hot embossing technique or a soft lithography patterning
technique. The manifold layer is alternatively formed by a laser
drilling process. The manifold layer is alternatively formed by a
soft lithography technique. The manifold layer is formed by a
machining process. The manifold layer is alternatively formed by an
injection molding, electrical discharge machining (EDM), stamping,
metal injection molding (MIM), cross cutting, and sawing
processes.
[0011] Other features and advantages of the present invention will
become apparent after reviewing the detailed description of the
preferred and alternative embodiments set forth below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1A illustrates a side view of a conventional heat
exchanger.
[0013] FIG. 1B illustrates a top view of the conventional heat
exchanger.
[0014] FIG. 1C illustrates a side view diagram of a prior art
multi-level heat exchanger.
[0015] FIG. 2A illustrates a schematic diagram of a closed loop
cooling system incorporating a alternative embodiment of the
flexible fluid delivery microchannel heat exchanger of the present
invention.
[0016] FIG. 2B illustrates a schematic diagram of a closed loop
cooling system incorporating an alternative embodiment of the
flexible fluid delivery microchannel heat exchanger of the present
invention.
[0017] FIG. 3A illustrates a top view of the alternative manifold
layer of the heat exchanger in accordance with the present
invention.
[0018] FIG. 3B illustrates an exploded view of the alternative heat
exchanger with the alternative manifold layer in accordance with
the present invention.
[0019] FIG. 4 illustrates a perspective view of the an interwoven
manifold layer in accordance with the present invention.
[0020] FIG. 5 illustrates a top view of the interwoven manifold
layer with interface layer in accordance with the present
invention.
[0021] FIG. 6A illustrates a cross-sectional view of the interwoven
manifold layer with interface layer of the present invention along
lines A-A.
[0022] FIG. 6B illustrates a cross-sectional view of the interwoven
manifold layer with interface layer of the present invention along
lines B-B.
[0023] FIG. 6C illustrates a cross-sectional view of the interwoven
manifold layer with interface layer of the present invention along
lines C-C.
[0024] FIG. 7A illustrates an exploded view of the interwoven
manifold layer with interface layer of the present invention.
[0025] FIG. 7B illustrates a perspective view of an alternative
embodiment of the interface layer of the present invention.
[0026] FIG. 8A illustrates a top view diagram of an alternate
manifold layer in accordance with the present invention.
[0027] FIG. 8B illustrates a top view diagram of the interface
layer in accordance with the present invention.
[0028] FIG. 8C illustrates a top view diagram of the interface
layer in accordance with the present invention.
[0029] FIG. 9A illustrates a side view diagram of the alternative
embodiment of the three tier heat exchanger in accordance with the
present invention.
[0030] FIG. 9B illustrates a side view diagram of the alternative
embodiment of the two tier heat exchanger in accordance with the
present invention.
[0031] FIGS. 10A-10E illustrate a perspective view of the interface
layer having different micro-pin arrays in accordance with the
present invention.
[0032] FIG. 11 illustrates a cut-away perspective view diagram of
the alternate heat exchanger in accordance with the present
invention.
[0033] FIG. 12A illustrates an exploded view of an alternative heat
exchanger in accordance with the present invention.
[0034] FIG. 12B illustrates an exploded view of an alternative heat
exchanger in accordance with the present invention.
[0035] FIG. 12C illustrates a perspective view of the alternative
circulation level in accordance with the present invention.
[0036] FIG. 12D illustrates a perspective view of the underside of
the alternative inlet level in accordance with the present
invention.
[0037] FIG. 12E illustrates a perspective view of the underside of
an alternative inlet level in accordance with the present
invention.
[0038] FIG. 12F illustrates a perspective view of the underside of
the alternative outlet level in accordance with the present
invention.
[0039] FIG. 12G illustrates a perspective view of the underside of
an alternative outlet level in accordance with the present
invention.
[0040] FIG. 12H illustrates a cross sectional view of the
alternative heat exchanger in accordance with the present
invention.
[0041] FIG. 12I illustrates a cross sectional view of the
alternative heat exchanger in accordance with the present
invention.
[0042] FIG. 13 illustrates a top view of the circulation level
having an arrangement of inlet and outlet apertures for single
phase fluid flow in accordance with the present invention.
[0043] FIG. 14 illustrates a top view of the circulation level
having an arrangement of inlet and outlet apertures for two phase
fluid flow in accordance with the present invention.
[0044] FIG. 15 illustrates a side view diagram of the interface
layer of the heat exchanger having a coating material applied
thereon in accordance with the present invention.
[0045] FIG. 16 illustrates a flow chart of an alternative method of
manufacturing the heat exchanger in accordance with the present
invention.
[0046] FIG. 17 illustrates a schematic of an alternate embodiment
of the present invention having two heat exchangers coupled to a
heat source.
[0047] FIG. 18 illustrates an exploded view of a preferred heat
exchanger in accordance with the present invention.
[0048] FIG. 19 illustrates an exploded view of the preferred heat
exchanger in accordance with the present invention.
[0049] FIG. 20 illustrates a cross-sectional view of the preferred
heat exchanger in accordance with the present invention.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0050] Generally, the heat exchanger captures thermal energy
generated from a heat source by passing fluid through selective
areas of the interface layer which is preferably coupled to the
heat source. In particular, the fluid is directed to specific areas
in the interface layer to cool the hot spots and areas around the
hot spots to generally create temperature uniformity across the
heat source while maintaining a small pressure drop within the heat
exchanger. As discussed in the different embodiments below, the
heat exchanger utilizes a plurality of apertures, channels and/or
fingers in the manifold layer as well as conduits in the
intermediate layer to direct and circulate fluid to and from
selected hot spot areas in the interface layer. Alternatively, the
heat exchanger includes several ports which are specifically
disposed in predetermined locations to directly deliver fluid to
and remove fluid from the hot spots to effectively cool the heat
source.
[0051] It is apparent to one skilled in the art that although the
microchannel heat exchanger of the present invention is described
and discussed in relation to cooling hot spot locations in a
device, the heat exchanger is alternatively used for heating a cold
spot location in a device. It should also be noted that although
the present invention is preferably described as a microchannel
heat exchanger, the present invention can be used in other
applications and is not limited to the discussion herein.
[0052] FIG. 2A illustrates a schematic diagram of a closed loop
hermetically sealed cooling system 30 which includes an alternative
flexible fluid delivery microchannel heat exchanger 100 in
accordance with the present invention. In addition, FIG. 2B
illustrates a schematic diagram of a closed loop cooling system 30
which includes an alternative flexible fluid delivery microchannel
heat exchanger 100 with multiple ports 108, 109 in accordance with
the present invention. It should be noted that the system
alternatively incorporates other heat exchanger embodiments herein
and is not limited to the alternative heat exchanger 100.
[0053] As shown in FIG. 2A, the fluid ports 108, 109 are coupled to
fluid lines 38 which are coupled to a pump 32 and heat condensor
30. The pump 32 pumps and circulates fluid within the closed loop
30. In one alternative, one fluid port 108 is used to supply fluid
to the heat exchanger 100. In addition, one fluid port 109 is used
to remove fluid from the heat exchanger 100. In one embodiment, a
uniform, constant amount of fluid flow enters and exits the heat
exchanger 100 via the respective fluid ports 108, 109.
Alternatively, different amounts of fluid flow enter and exit
through the inlet and outlet port(s) 108, 109 at a given time.
Alternatively, as shown in FIG. 2B, one pump provides fluid to
several designated inlet ports 108. Alternatively, multiple pumps
(not shown), provide fluid to their respective inlet and outlet
ports 108, 109. In addition, the dynamic sensing and control module
34 is alternatively employed in the system to variate and
dynamically control the amount and flow rate of fluid entering and
exiting the preferred or alternative heat exchanger in response to
varying hot spots or changes in the amount of heat in a hot spot
location as well as the locations of the hot spots.
[0054] FIG. 3B illustrates an exploded view of the alternative
three tier heat exchanger 100 with the alternative manifold layer
in accordance with the present invention. The alternative
embodiment, as shown in FIG. 3B, is a three level heat exchanger
100 which includes an interface layer 102, at least one
intermediate layer 104 and at least one manifold layer 106.
Alternatively, as discussed below, the heat exchanger 100 is a two
level apparatus which includes the interface layer 102 and the
manifold layer 106. As shown in FIGS. 2A and 2B, the heat exchanger
100 is coupled to a heat source 99, such as an electronic device,
including, but not limited to a microchip and integrated circuit,
whereby a thermal interface material 98 is preferably disposed
between the heat source 99 and the heat exchanger 100.
Alternatively, the heat exchanger 100 is directly coupled to the
surface of the heat source 99. It is also apparent to one skilled
in the art that the heat exchanger 100 is alternatively integrally
formed into the heat source 99, whereby the heat exchanger 100 and
the heat source 99 are formed as one piece. Thus, the interface
layer 102 is integrally disposed with the heat source 99 and is
formed as one piece with the heat source. In addition, a
thermoelectric device 97 is alternatively configured in between the
thermal interface material 98 and the heat source 99. More detail
of the thermoelectric device 97 is discussed below.
[0055] It is preferred that the microchannel heat exchanger of the
present invention is configured to be directly or indirectly in
contact with the heat source 99 which is rectangular in shape, as
shown in the figures. However, it is apparent to one skilled in the
art that the heat exchanger 100 can have any other shape conforming
with the shape of the heat source 99. For example, the heat
exchanger of the present invention can be configured to have an
outer semicircular shape which allows the heat exchanger (not
shown) to be in direct or indirect contact with a corresponding
semicircular shaped heat source (not shown). In addition, it is
preferred that the heat exchanger is slightly larger in dimension
than the heat source within the range of and including 0.5-5.0
millimeters.
[0056] FIG. 3A illustrates a top view of the alternate manifold
layer 106 of the present invention. In particular, as shown in FIG.
3B, the manifold layer 106 includes four sides as well as a top
surface 130 and a bottom surface 132. However, the top surface 130
is removed in FIG. 3A to adequately illustrate and describe the
workings of the manifold layer 106. As shown in FIG. 3A, the
manifold layer 106 has a series of channels or passages 116, 118,
120, 122 as well as ports 108, 109 formed therein. The fingers 118,
120 extend completely through the body of the manifold layer 106 in
the Z-direction as shown in FIG. 3B. Alternatively, the fmgers 118
and 120 extend partially through the manifold layer 106 in the
Z-direction and have apertures as shown in FIG. 3A. In addition,
passages 116 and 122 extend partially through the manifold layer
106. The remaining areas between the inlet and outlet passages 116,
120, designated as 107, extend from the top surface 130 to the
bottom surface 132 and form the body of the manifold layer 106.
[0057] As shown in FIG. 3A, the fluid enters manifold layer 106 via
the inlet port 108 and flows along the inlet channel 116 to several
fingers 118 which branch out from the channel 116 in several
directions in the X and/or Y directions to apply fluid to selected
regions in the interface layer 102. The fingers 118 are arranged in
different predetermined directions to deliver fluid to the
locations in the interface layer 102 corresponding to the areas at
or near the hot spots in the heat source. These locations in the
interface layer 102 are hereinafter referred to as interface hot
spot regions. The fingers are configured to cool stationary as well
as temporally varying interface hot spot regions. As shown in FIG.
3A, the channels 116, 122 and fingers 118, 120 are disposed in the
X and/or Y directions in the manifold layer 106. Thus, the various
directions of the channels 116, 122 and fingers 118, 120 allow
delivery of fluid to cool hot spots in the heat source 99 and/or
minimize pressure drop within the heat exchanger 100.
Alternatively, channels 116, 122 and fingers 118, 120 are
periodically disposed in the manifold layer 106 and exhibit a
pattern, as in the example shown in FIGS. 4 and 5.
[0058] The arrangement as well as the dimensions of the fingers
118, 120 are determined in light of the hot spots in the heat
source 99 that are desired to be cooled. The locations of the hot
spots as well as the amount of heat produced near or at each hot
spot are used to configure the manifold layer 106 such that the
fingers 118, 120 are placed above or proximal to the interface hot
spot regions in the interface layer 102. The manifold layer 106
allows one phase and/or two-phase fluid to circulate to the
interface layer 102 without allowing a substantial pressure drop
from occurring within the heat exchanger 100 and the system 30
(FIG. 2A). The fluid delivery to the interface hot spot regions
creates a uniform temperature at the interface hot spot region as
well as areas in the heat source adjacent to the interface hot spot
regions.
[0059] The dimensions as well as the number of channels 116 and
fingers 118 depend on a number of factors. In one embodiment, the
inlet and outlet fingers 118, 120 have the same width dimensions.
Alternatively, the inlet and outlet fingers 118, 120 have different
width dimensions. The width dimensions of the fingers 118, 120 are
within the range of and including 0.25-0.50 millimeters. In one
embodiment, the inlet and outlet fingers 118, 120 have the same
length and depth dimensions. Alternatively, the inlet and outlet
fingers 118, 120 have different length and depth dimensions. In
another embodiment, the inlet and outlet fingers 118, 120 have
varying width dimensions along the length of the fingers. The
length dimensions of the inlet and outlet fingers 118, 120 are
within the range of and including 0.5 millimeters to three times
the size of the heat source length. In addition, the fingers 118,
120 have a height or depth dimension within the range and including
0.25-0.50 millimeters. In addition, less than 10 or more than 30
fingers per centimeter are alternatively disposed in the manifold
layer 106. However, it is apparent to one skilled in the art that
between 10 and 30 fingers per centimeter in the manifold layer is
also contemplated.
[0060] It is contemplated within the present invention to tailor
the geometries of the fingers 118, 120 and channels 116, 122 to be
in non-periodic arrangement to aid in optimizing hot spot cooling
of the heat source. In order to achieve a uniform temperature
across the heat source 99, the spatial distribution of the heat
transfer to the fluid is matched with the spatial distribution of
the heat generation. As the fluid flows along the interface layer
through the microchannels 110, its temperature increases and as it
begins to transform to vapor under two-phase conditions. Thus, the
fluid undergoes a significant expansion which results in a large
increase in velocity. Generally, the efficiency of the heat
transfer from the interface layer to the fluid is improved for high
velocity flow. Therefore, it is possible to tailor the efficiency
of the heat transfer to the fluid by adjusting the cross-sectional
dimensions of the fluid delivery and removal fingers 118, 120 and
channels 116, 122 in the heat exchanger 100.
[0061] For example, a particular finger can be designed for a heat
source where there is higher heat generation near the inlet. In
addition, it may be advantageous to design a larger cross section
for the regions of the fingers 118, 120 and channels 116, 122 where
a mixture of fluid and vapor is expected. Although not shown, a
finger can be designed to start out with a small cross sectional
area at the inlet to cause high velocity flow of fluid. The
particular finger or channel can also be configured to expand to a
larger cross-section at a downstream outlet to cause a lower
velocity flow. This design of the finger or channel allows the heat
exchanger to minimize pressure drop and optimize hot spot cooling
in areas where the fluid increases in volume, acceleration and
velocity due to transformation from liquid to vapor in two-phase
flow.
[0062] In addition, the fingers 118, 120 and channels 116, 122 can
be designed to widen and then narrow again along their length to
increase the velocity of the fluid at different places in the
microchannel heat exchanger 100. Alternatively, it is appropriate
to vary the finger and channel dimensions from large to small and
back again many times over in order to tailor the heat transfer
efficiency to the expected heat dissipation distribution across the
heat source 99. It should be noted that the above discussion of the
varying dimensions of the fingers and channels also apply to the
other embodiments discussed and is not limited to this
embodiment.
[0063] Alternatively, as shown in FIG. 3A, the manifold layer 106
includes one or more apertures 119 in the inlet fingers 118. In the
three tier heat exchanger 100, the fluid flowing along the fingers
118 flows down the apertures 119 to the intermediate layer 104.
Alternatively, in the two-tier heat exchanger 100, the fluid
flowing along the fingers 118 flows down the apertures 119 directly
to the interface layer 102. In addition, as shown in FIG. 3A, the
manifold layer 106 includes apertures 121 in the outlet fingers
120. In the three tier heat exchanger 100, the fluid flowing from
the intermediate layer 104 flows up the apertures 121 into the
outlet fingers 120. Alternatively, in the two-tier heat exchanger
100, the fluid flowing from the interface layer 102 flows directly
up the apertures 121 into the outlet fingers 120.
[0064] In the alternative embodiment, the inlet and outlet fingers
118, 120 are open channels which do not have apertures. The bottom
surface 103 of the manifold layer 106 abuts against the top surface
of the intermediate layer 104 in the three tier exchanger 100 or
abuts against the interface layer 102 in the two tier exchanger.
Thus, in the three-tier heat exchanger 100, fluid flows freely to
and from the intermediate layer 104 and the manifold layer 106. The
fluid is directed to and from the appropriate interface hot spot
region by conduits 105 the intermediate layer 104. It is apparent
to one skilled in the art that the conduits 105 are directly
aligned with the fingers, as described below or positioned
elsewhere in the three tier system.
[0065] Although FIG. 3B shows the alternative three tier heat
exchanger 100 with the alternative manifold layer, the heat
exchanger 100 is alternatively a two layer structure which includes
the manifold layer 106 and the interface layer 102, whereby fluid
passes directly between the manifold layer 106 and interface layer
102 without passing through the interface layer 104. It is apparent
to one skilled in the art that the configuration of the manifold,
intermediate and interface layers are shown for exemplary purposes
and is thereby not limited to the configuration shown.
[0066] As shown in FIG. 3B, the intermediate layer 104 includes a
plurality of conduits 105 which extend therethrough. The inflow
conduits 105 direct fluid entering from the manifold layer 106 to
the designated interface hot spot regions in the interface layer
102. Similarly, the apertures 105 also channel fluid flow from the
interface layer 102 to the exit fluid port(s) 109. Thus, the
intermediate layer 104 also provides fluid delivery from the
interface layer 102 to the exit fluid port 109 where the exit fluid
port 108 is in communication with the manifold layer 106.
[0067] The conduits 105 are positioned in the interface layer 104
in a predetermined pattern based on a number of factors including,
but not limited to, the locations of the interface hot spot
regions, the amount of fluid flow needed in the interface hot spot
region to adequately cool the heat source 99 and the temperature of
the fluid. The conduits have a width dimension of 100 microns,
although other width dimensions are contemplated up to several
millimeters. In addition, the conduits 105 have other dimensions
dependent on at least the above mentioned factors. It is apparent
to one skilled in the art that each conduit 105 in the intermediate
layer 104 has the same shape and/or dimension, although it is not
necessary. For instance, like the fingers described above, the
conduits alternatively have a varying length and/or width
dimension. Additionally, the conduits 105 have a constant depth or
height dimension through the intermediate layer 104. Alternatively,
the conduits 105 have a varying depth dimension, such as a
trapezoidal or a nozzle-shape, through the intermediate layer 104.
Although the horizontal shape of the conduits 105 are shown to be
rectangular in FIG. 2C, the conduits 105 alternatively have any
other shape including, but not limited to, circular (FIG. 3A),
curved, elliptical. Alternatively, one or more of the conduits 105
are shaped and contour with a portion of or all of the finger or
fingers above.
[0068] The intermediate layer 104 is horizontally positioned within
the heat exchanger 100 with the conduits 105 positioned vertically.
Alternatively, the intermediate layer 104 is positioned in any
other direction within the heat exchanger 100 including, but not
limited to, diagonal and curved forms. Alternatively, the conduits
105 are positioned within the intermediate layer 104 in a
horizontally, diagonally, curved or any other direction. In
addition, the intermediate layer 104 extends horizontally along the
entire length of the heat exchanger 100, whereby the intermediate
layer 104 completely separates the interface layer 102 from the
manifold layer 106 to force the fluid to be channeled through the
conduits 105. Alternatively, a portion of the heat exchanger 100
does not include the intermediate layer 104 between the manifold
layer 106 and the interface layer 102, whereby fluid is free to
flow therebetween. Further, the intermediate layer 104
alternatively extends vertically between the manifold layer 106 and
the interface layer 102 to form separate, distinct intermediate
layer regions. Alternatively, the intermediate layer 104 does not
fully extend from the manifold layer 106 to interface layer
102.
[0069] FIG. 10A illustrates a perspective view of one embodiment of
the interface layer 302 in accordance with the present invention.
As shown in FIG. 10A, the interface layer 302 includes a series of
pillars 303 which extend upwards from the bottom surface 301 of the
interface layer 302. In addition, FIG. 10A illustrates a
microporous structure 301 disposed on the bottom surface of the
interface layer 302. It is apparent that the interface layer 302
can include only the microporous structure 301 as well as a
combination of the microporous structure with any other interface
layer feature (e.g. microchannels, pillars, etc.). More details
regarding the microporous structure are discussed below.
[0070] As will be discussed in more detail below, the fluid travels
down to the interface layer 302 via a series of inlet apertures,
whereby the fluid then exits from the interface layer 302 via a
series of outlet apertures which are spaced an optimal distance to
the inlet apertures. In other words, the fluid travels away from
each inlet aperture toward the closest outlet aperture. In one
embodiment, each inlet aperture is surrounded by outlet apertures.
Thus, fluid entering the interface layer 302 will flow in the
direction toward the surrounding outlet apertures. Accordingly, the
pillars 303 in the interface layer 302 accommodate sufficient heat
transfer to the fluid as well as allow the fluid to experience the
lease amount of pressure drop while flowing from the inlet
apertures to the outlet apertures.
[0071] The interface layer 302 alternatively includes a dense array
of tall, narrow pillars 303 which extend perpendicular from the
bottom surface 301 are in contact with the bottom surface of the
manifold layer. Alternatively, the pillars 303 are not in contact
with the bottom surface of the manifold layer. In addition, at
least one of the pillars 303 alternatively extend at an angle with
respect to the bottom surface 301 of the interface layer 302. The
pillars 303 are also equidistantly spaced from one another along
the interface layer 302 such that the heat transfer capabilities of
the interface layer 302 are uniform across its bottom surface 301.
Alternatively, the pillars 303 are spaced apart non-equidistantly
as shown in FIG. 10B, in which the pillars 303 in the middle of the
interface layer 302 are spaced further apart than the pillars 303
at the edges. The pillars 303 are spaced apart depending on the
dimensions of the heat source 99, and the flow resistance to the
fluid as well as the size and locations of the hot spots and the
heat flux density from the heat source 99. For instance, a lower
density of pillars 303 will offer less resistance to the flow, but
will also offer less surface area for heat transfer from the
interface layer 302 to the fluid. It should be noted that the
configuration of the non-periodically spaced pillars 303 shown in
the embodiment in FIG. 1OB are not limited thereto and are
configured in any other arrangement depending on the conditions of
the heat source as well as the desired operation of the cooling
system 30 (FIG. 2A).
[0072] In addition, the pillars 303 are circular cylinders as shown
in FIG. 10A to allow the fluid to flow from the inlet apertures to
the outlet apertures with least amount of resistance. However, the
pillars 303 alternatively have shapes including, but not limited to
squared 303B (FIG. 10B), diamond, elliptical 303C (FIG. 10C),
hexagonal 303D (FIG. 10D) or any other shape. In addition, the
interface layer 302 alternatively has a combination of differently
shaped pillars along the bottom surface 301.
[0073] For instance, as shown in FIG. 10E, the interface layer 302
includes several sets of rectangular fins 303E which are radially
disposed with respect to one another in their respective set. In
addition, the interface layer 302 includes several pillars 303B
disposed in between the sets of rectangular fins 303E. In one
embodiment, the open circular areas within the radially arranged
rectangular fins 303E are placed below each inlet aperture, whereby
the fins 303E assist in guiding the flow to the outlet apertures.
Thus, the radially distributed fins 303E assist in minimizing the
pressure drop while allowing nearly uniform distribution of cooling
fluid throughout the interface layer 302. Depending on the size and
relative placement of the inlet and outlet apertures, there are
many possible configurations of the pillars and/or fins, and the
selection of the optimal arrangement of the interface layer 302
depends on whether the fluid undergoes single-phase flow or
two-phase flow conditions. It is apparent to one skilled in the art
that the various pin 303 configurations can be incorporated with
any of the embodiments and variations thereof discussed herein.
[0074] It is preferred that the heat exchanger 100 of the present
invention is larger in width than the heat source 99. In the case
where the heat exchanger 100 is larger than the heat source 99, an
overhang dimension exists. The overhang dimension is the farthest
distance between one outer wall of the heat source 99 and the
interior fluid channel wall of the heat exchanger 100, such as the
inner wall of the inlet port 316 (FIG. 12A). In the preferred
embodiment, the overhang dimension is within the range of and
including 0 to 5 millimeters for single phase and 0 to 15
millimeters for two phase fluid. In addition, the interface layer
302 of the present invention preferably has a thickness dimension
within the range of and including 0.3 to 0.7 millimeters for single
phase fluid and 0.3 to 1.0 millimeters for two phase fluid.
[0075] In the embodiment of the heat exchanger which utilizes a
microporous structure 301 disposed upon the interface layer 302,
the microporous structure 301 has an average pore size within the
range of and including 10 to 200 microns for single phase as well
as two phase fluid. In addition, the microporous structure 301 has
a porosity within the range and including 50 to 80 percent for
single phase as well as two phase fluid. The height of the
microporous structure 301 is within the range of and including 0.25
to 2.00 millimeters for single phase as well as two phase
fluid.
[0076] In the embodiment which utilizes pillars and/or
microchannels along the interface layer 302, the interface layer
302 of the present invention has a thickness dimension in the range
of and including 0.3 to 0.7 millimeters for single phase fluid and
0.3 to 1.0 millimeters for two phase fluid. In addition, the area
of at least one pillar is in the range of and including (10
micron).sup.2 and (100 micron).sup.2 for single phase as well as
two phase fluid. In addition, the area of the separation distance
between at least two of the pillars and/or microchannels is in the
range of and including 10 microns to 150 microns for single phase
as well as two phase fluid. The width dimension of the
microchannels are in the range of and including 10 to 100 microns
for single phase as well as two phase fluid. The height dimension
of the microchannels and/or pillars is within the range of and
including 50 to 800 microns for single phase fluid and 50 microns
to 2 millimeters for two phase fluid. It is contemplated by one
skilled in the art that other dimension are alternatively
contemplated.
[0077] FIG. 3B illustrates a perspective view of another embodiment
of the interface layer 102 in accordance with the present
invention. As shown in FIG. 3B, the interface layer 102 includes a
bottom surface 103 and a plurality of microchannel walls 110,
whereby the area in between the microchannel walls 110 channels or
directs fluid along a fluid flow path. The bottom surface 103 is
flat and has a high thermal conductivity to allow sufficient heat
transfer from the heat source 99. Alternatively, the bottom surface
103 includes troughs and/or crests designed to collect or repel
fluid from a particular location. The microchannel walls 110 are
configured in a parallel configuration, as shown in FIG. 3B,
whereby fluid flows between the microchannel walls 110 along a
fluid path.
[0078] It is apparent to one skilled in the art that the
microchannel walls 110 are alternatively configured in any other
appropriate configuration depending on the factors discussed above.
For instance, the interface layer 102 alternatively has grooves in
between sections of microchannel walls 110, as shown in FIG. 8C. In
addition, the microchannel walls 110 have dimensions which minimize
the pressure drop or differential within the interface layer 102.
It is also apparent that any other features, besides microchannel
walls 110 are also contemplated, including, but not limited to
roughed surfaces and a micro-porous structure, such as sintered
metal and silicon foam. However, for exemplary purposes, the
parallel microchannel walls 110 shown in FIG. 3B is used to
describe the interface layer 102 in the present invention.
Alternatively, the microchannel walls 110 have non-parallel
configurations.
[0079] The microchannel walls 110 allow the fluid to undergo
thermal exchange along the selected hot spot locations of the
interface hot spot region to cool the heat source 99 in that
location. The microchannel walls 110 have a width dimension within
the range of 10-100 microns and a height dimension within the range
of 50 microns to two millimeters, depending on the power of the
heat source 99. The microchannel walls 110 have a length dimension
which ranges between 100 microns and several centimeters, depending
on the dimensions of the heat source, as well as the size of the
hot spots and the heat flux density from the heat source.
Alternatively, any other microchannel wall dimensions are
contemplated. The microchannel walls 110 are spaced apart by a
separation dimension range of 50-500 microns, depending on the
power of the heat source 99, although any other separation
dimension range is contemplated.
[0080] Referring back to the-assembly in FIG. 3B, the top surface
of the manifold layer 106 is cut away to illustrate the channels
116, 122 and fingers 118, 120 within the body of the manifold layer
106. The locations in the heat source 99 that produce more heat are
hereby designated as hot spots, whereby the locations in the heat
source 99 which produce less heat are hereby designated as warm
spots. As shown in FIG. 3B, the heat source 99 is shown to have a
hot spot region, namely at location A, and a warm spot region,
namely at location B. The areas of the interface layer 102 which
abut the hot and warm spots are accordingly designated interface
hot spot regions. As shown in FIG. 3B, the interface layer 102
includes interface hot spot region A, which is positioned above
location A and interface hot spot region B, which is positioned
above location B.
[0081] As shown in FIGS. 3A and 3B, fluid initially enters the heat
exchanger 100 through one inlet port 108. The fluid then flows to
one inlet channel 116. Alternatively, the heat exchanger 100
includes more than one inlet channel 116. As shown in FIGS. 3A and
3B, fluid flowing along the inlet channel 116 from the inlet port
108 initially branches out to finger 118D. In addition, the fluid
which continues along the rest of the inlet channel 116 flows to
individual fingers 118B and 118C and so on.
[0082] In FIG. 3B, fluid is supplied to interface hot spot region A
by flowing to the finger 118A, whereby fluid flows down through
finger 118A to the intermediate layer 104. The fluid then flows
through the inlet conduit 105A, positioned below the finger 118A,
to the interface layer 102, whereby the fluid undergoes thermal
exchange with the heat source 99. As described, the microchannels
in the interface layer 102 are configureable in any direction.
Thus, the microchannels 111 in interface region A are positioned
perpendicular to the rest of the microchannels 110 in the interface
layer 102. Thus, the fluid from conduit 105A travels along the
microchannels 111 as shown in FIG. 3B, although the fluid travel in
other directions along the remaining areas of the interface layer
102. The heated liquid then travels upward through the conduit 105B
to the outlet finger 120A.
[0083] Similarly, fluid flows down in the Z-direction through
fingers 118E and 118F to the intermediate layer 104. The fluid then
flows through the inlet conduit 105C down in the Z-direction to the
interface layer 102. The heated fluid then travels upward in the
Z-direction from the interface layer 102 through the outlet conduit
105D to the outlet fingers 120E and 120F. The heat exchanger 100
removes the heated fluid in the manifold layer 106 via the outlet
fingers 120, whereby the outlet fingers 120 are in communication
with the outlet channel 122. The outlet channel 122 allows fluid to
flow out of the heat exchanger through one outlet port 109.
[0084] In one embodiment, the inflow and outflow conduits 105 are
also positioned directly or nearly directly above the appropriate
interface hot spot regions to directly apply fluid to hot spots in
the heat source 99. In addition, each outlet finger 120 is
configured to be positioned closest to a respective inlet finger
118 for a particular interface hot spot region to minimize pressure
drop therebetween. Thus, fluid enters the interface layer 102 via
the inlet finger 118A and travels the least amount of distance
along the bottom surface 103 of the interface layer 102 before it
exits the interface layer 102 to the outlet finger 120A. It is
apparent that the amount of distance which the fluid travels along
the bottom surface 103 adequately removes heat generated from the
heat source 99 without generating an unnecessary amount of pressure
drop. In addition, as shown in FIGS. 3A and 3B, the corners in the
fingers 118, 120 are curved to reduce pressure drop of the fluid
flowing along the fingers 118.
[0085] It is apparent to one skilled in the art that the
configuration of the manifold layer 106 shown in FIGS. 3A and 3B is
only for exemplary purposes. The configuration of the channels 116
and fingers 118 in the manifold layer 106 depend on a number of
factors, including but not limited to, the locations of the
interface hot spot regions, amount of flow to and from the
interface hot spot regions as well as the amount of heat produced
by the heat source in the interface hot spot regions. For instance,
one possible configuration of the manifold layer 106 includes an
interdigitated pattern of parallel inlet and outlet fingers that
are alternatively arranged along the width of the manifold layer,
as shown in FIGS. 4-7A and discussed below. Nonetheless, any other
configuration of channels 116 and fingers 118 is contemplated.
[0086] FIG. 4 illustrates a perspective view of an alternative
manifold layer 406 in accordance with the heat exchanger of the
present invention. The manifold layer 406 in FIG. 4 includes a
plurality of interwoven or inter-digitated parallel fluid fingers
411, 412 which allow one phase and/or two-phase fluid to circulate
to the interface layer 402 without allowing a substantial pressure
drop from occurring within the heat exchanger 400 and the system 30
(FIG. 2A). As shown in FIG. 8, the inlet fingers 411 are arranged
alternately with the outlet fingers 412. However, it is
contemplated by one skilled in the art that a certain number of
inlet or outlet fingers can be arranged adjacent to one another and
is thereby not limited to the alternating configuration shown in
FIG. 4. In addition, the fingers are alternatively designed such
that a parallel finger branches off from or is linked to another
parallel finger. Thus, it is possible to have many more inlet
fingers than outlet fingers and vice versa.
[0087] The inlet fingers or passages 411 supply the fluid entering
the heat exchanger to the interface layer 402, and the outlet
fingers or passages 412 remove the fluid from the interface layer
402 which then exits the heat exchanger 400. The shown
configuration of the manifold layer 406 allows the fluid to enter
the interface layer 402 and travel a very short distance in the
interface layer 402 before it enters the outlet passage 412. The
substantial decrease in the length that the fluid travels along the
interface layer 402 substantially decreases the pressure drop in
the heat exchanger 400 and the system 30 (FIG. 2A).
[0088] As shown in FIGS. 4-5, the alternative manifold layer 406
includes a passage 414 which is in communication with two inlet
passages 411 and provides fluid thereto. As shown in FIGS. 8-9 the
manifold layer 406 includes three outlet passages 412 which are in
communication with passage 418. The passages 414 in the manifold
layer 406 have a flat bottom surface which channels the fluid to
the fingers 411, 412. Alternatively, the passage 414 has a slight
slope which aids in channeling the fluid to selected fluid passages
411. Alternatively, the inlet passage 414 includes one or more
apertures in its bottom surface which allows a portion of the fluid
to flow down to the interface layer 402. Similarly, the passage 418
in the manifold layer has a flat bottom surface which contains the
fluid and channels the fluid to the port 408. Alternatively, the
passage 418 has a slight slope which aids in channeling the fluid
to selected outlet ports 408. In addition, the passages 414, 418
have a dimension width of approximately 2 millimeters, although any
other width dimensions are alternatively contemplated.
[0089] The passages 414, 418 are in communication with ports 408,
409 whereby the ports are coupled to the fluid lines 38 in the
system 30 (FIG. 2A). The manifold layer 406 includes horizontally
configured fluid ports 408, 409. Altematively, the manifold layer
406 includes vertically and/or diagonally configured fluid ports
408, 409, as discussed below, although not shown in FIG. 4-7.
Alternatively, the manifold layer 406 does not include passage 414.
Thus, fluid is directly supplied to the fingers 411 from the ports
408. Again, the manifold layer 411 alternatively does not include
passage 418, whereby fluid in the fingers 412 directly flows out of
the heat exchanger 400 through ports 408. It is apparent that
although two ports 408 are shown in communication with the passages
414, 418, any other number of ports are alternatively utilized.
[0090] The inlet passages 411 have dimensions which allow fluid to
travel to the interface layer without generating a large pressure
drop along the passages 411 and the system 30 (FIG. 2A). The inlet
passages 411 have a width dimension in the range of and including
0.25-5.00 millimeters, although any other width dimensions are
alternatively contemplated. In addition, the inlet passages 411
have a length dimension in the range of and including 0.5
millimeters to three times the length of the heat source.
Alternatively, other length dimensions are contemplated. In
addition, as stated above, the inlet passages 411 extend down to or
slightly above the height of the microchannels 410 such that the
fluid is channeled directly to the microchannels 410. The inlet
passages 411 have a height dimension in the range of and including
0.25-5.00 millimeters. It is apparent to one skilled in the art
that the passages 411 do not extend down to the microchannels 410
and that any other height dimensions are alternatively
contemplated. It is apparent to one skilled in the art that
although the inlet passages 411 have the same dimensions, it is
contemplated that the inlet passages 411 alternatively have
different dimensions. In addition, the inlet passages 411
alternatively have varying widths, cross sectional dimensions
and/or distances between adjacent fingers. In particular, the
passage 411 has areas with a larger width or depths as well as
areas with narrower widths and depths along its length. The varied
dimensions allow more fluid to be delivered to predetermined
interface hot spot regions in the interface layer 402 through wider
portions while restricting flow to warm spot interface hot spot
regions through the narrow portions.
[0091] In addition, the outlet passages 412 have dimensions which
allow fluid to travel to the interface layer without generating a
large pressure drop along the passages 412 as well as the system 30
(FIG. 2A). The outlet passages 412 have a width dimension in the
range of and including 0.25-5.00 millimeters, although any other
width dimensions are alternatively contemplated. In addition, the
outlet passages 412 have a length dimension in the range of and
including 0.5 millimeters to three times the length of the heat
source. In addition, the outlet passages 412 extend down to the
height of the microchannels 410 such that the fluid easily flows
upward in the outlet passages 412 after horizontally flowing along
the microchannels 410. The inlet passages 411 have a height
dimension in the range of and including 0.25-5.00 millimeters,
although any other height dimensions are alternatively
contemplated. It is apparent to one skilled in the art that
although outlet passages 412 have the same dimensions, it is
contemplated that the outlet passages 412 alternatively have
different dimensions. Again, the inlet passage 412 alternatively
have varying widths, cross sectional dimensions and/or distances
between adjacent fingers.
[0092] The inlet and outlet passages 411, 412 are segmented and
distinct from one another, as shown in FIGS. 4 and 5, whereby fluid
among the passages do not mix together. In particular, as shown in
FIG. 8, two outlet passages are located along the outside edges of
the manifold layer 406, and one outlet passage 412 is located in
the middle of the manifold layer 406. In addition, two inlet
passages 411 are configured on adjacent sides of the middle outlet
passage 412. This particular configuration causes fluid entering
the interface layer 402 to travel a short distance in the interface
layer 402 before it flows out of the interface layer 402 through
the outlet passage 412. However, it is apparent to one skilled in
the art that the inlet passages and outlet passages are positioned
in any other appropriate configuration and is thereby not limited
to the configuration shown and described in the present disclosure.
The number of inlet and outlet fingers 411, 412 are more than three
within the manifold layer 406 but less than 10 per centimeter
across the manifold layer 406. It is also apparent to one skilled
in the art that any other number of inlet passages and outlet
passages are used and thereby is not limited to the number shown
and described in the present disclosure.
[0093] The manifold layer 406 is coupled to the intermediate layer
(not shown), whereby the intermediate layer (not shown) is coupled
to the interface layer 402 to form a three-tier heat exchanger 400.
The intermediate layer discussed herein is referred to above in the
embodiment shown in FIG. 3B. The manifold layer 406 is
alternatively coupled to the interface layer 402 and positioned
above the interface layer 402 to form a two-tier heat exchanger
400, as shown in FIG. 7A. FIGS. 6A-6C illustrate cross-sectional
schematics of the alternative manifold layer 406 coupled to the
interface layer 402 in the two tier heat exchanger. Specifically,
FIG. 6A illustrates the cross section of the heat exchanger 400
along line A-A in FIG. 5. In addition, FIG. 6B illustrates the
cross section of the heat exchanger 400 along line B-B and FIG. 6C
illustrates the cross section of the heat exchanger 400 along line
C-C in FIG. 5. As stated above, the inlet and outlet passages 411,
412 extend from the top surface to the bottom surface of the
manifold layer 406. When the manifold layer 406 and the interface
layer 402 are coupled to one another, the inlet and outlet passages
411, 412 are at or slightly above the height of the microchannels
410 in the interface layer 402. This configuration causes the fluid
from the inlet passages 411 to easily flow from the passages 411
through the microchannels 410. In addition, this configuration
causes fluid flowing through the microchannels to easily flow
upward through the outlet passages 412 after flowing through the
microchannels 410.
[0094] In the alternative embodiment, the intermediate layer 104
(FIG. 3B) is positioned between the manifold layer 406 and the
interface layer 402, although not shown in the figures. The
intermediate layer 104 (FIG. 3B) channels fluid flow to designated
interface hot spot regions in the interface layer 402. In addition,
the intermediate layer 104 (FIG. 3B) can be utilized to provide a
uniform flow of fluid entering the interface layer 402. Also, the
intermediate layer 104 is utilized to provide fluid to interface
hot spot regions in the interface layer 402 to adequately cool hot
spots and create temperature uniformity in the heat source 99. The
inlet and outlet passages 411, 412 are positioned near or above hot
spots in the heat source 99 to adequately cool the hot spots,
although it is not necessary.
[0095] FIG. 7A illustrates an exploded view of the alternate
manifold layer 406 with the an alternative interface layer 102 of
the present invention. The interface layer 102 includes continuous
arrangements of microchannel walls 110, as shown in FIG. 3B. In
general operation, similar to the manifold layer 106 shown in FIG.
3B, fluid enters the manifold layer 406 at fluid port 408 and
travels through the passage 414 and towards the fluid fingers or
passages 411. The fluid enters the opening of the inlet fingers 411
and flows the length of the fingers 411 in the X-direction, as
shown by the arrows. In addition, the fluid flows downward in the Z
direction to the interface layer 402 which is positioned below to
the manifold layer 406. As shown in FIG. 7A, the fluid in the
interface layer 402 traverses along the bottom surface in the X and
Y directions of the interface layer 402 and performs thermal
exchange with the heat source 99. The heated fluid exits the
interface layer 402 by flowing upward in the Z-direction via the
outlet fingers 412, whereby the outlet fingers 412 channel the
heated fluid to the passage 418 in the manifold layer 406 in the
X-direction. The fluid then flows along the passage 418 and exits
the heat exchanger by flowing out through the port 409.
[0096] The interface layer, as shown in FIG. 7A, includes a series
of grooves 416 disposed in between sets of microchannels 410 which
aid in channeling fluid to and from the passages 411, 412. In
particular, the grooves 416A are located directly beneath the inlet
passages 411 of the alternate manifold layer 406, whereby fluid
entering the interface layer 402 via the inlet passages 411 is
directly channeled to the microchannels adjacent to the groove
416A. Thus, the grooves 416A allow fluid to be directly channeled
into specific designated flow paths from the inlet passages 411, as
shown in FIG. 5. Similarly, the interface layer 402 includes
grooves 416B which are located directly beneath the outlet passages
412 in the Z-direction. Thus, fluid flowing horizontally along the
microchannels 410 toward the outlet passages are channeled
horizontally to the grooves 416B and vertically to the outlet
passage 412 above the grooves 416B.
[0097] FIG. 6A illustrates the cross section of the heat exchanger
400 with manifold layer 406 and interface layer 402. In particular,
FIG. 6A shows the inlet passages 411 interwoven with the outlet
passages 412, whereby fluid flows down the inlet passages 411 and
up the outlet passages 412. In addition, as shown in FIG. 6A, the
fluid flows horizontally through the microchannel walls 410 which
are disposed between the inlet passages and outlet passages and
separated by the grooves 416A, 416B. Alternatively, the
microchannel walls are continuous (FIG. 3B) and are not separated
by the microchannels 410. As shown in FIG. 6A, either or both of
the inlet and outlet passages 411, 412 have a curved surface 420 at
their ends at the location near the grooves 416. The curved surface
420 directs fluid flowing down the passage 411 towards the
microchannels 410 which are located adjacent to the passage 411.
Thus, fluid entering the interface layer 102 is more easily
directed toward the microchannels 410 instead of flowing directly
to the groove 416A. Similarly, the curved surface 420 in the outlet
passages 412 assists in directing fluid from the microchannels 410
to the outer passage 412.
[0098] In an alternative embodiment, as shown in FIG. 7B, the
interface layer 402' includes the inlet passages 411' and outlet
passages 412' discussed above with respect to the manifold layer
406 (FIGS. 8-9). In the alternative embodiment, the fluid is
supplied directly to the interface layer 402' from the port 408'.
The fluid flows along the passage 414' towards the inlet passages
411'. The fluid then traverses laterally along the sets of
microchannels 410' and undergoes heat exchange with the heat source
(not shown) and flows to the outlet passages 412'. The fluid then
flows along the outlet passages 412' to passage 418', whereby the
fluid exits the interface layer 402' by via the port 409'. The
ports 408', 409' are configured in the interface layer 402' and are
alternatively configured in the manifold layer 406 (FIG. 7A).
[0099] It is apparent to one skilled in the art that although all
of the heat exchangers in the present application are shown to
operate horizontally, the heat exchanger alternatively operates in
a vertical position. While operating in the vertical position, the
heat exchangers are alternatively configured such that each inlet
passage is located above an adjacent outlet passage. Therefore,
fluid enters the interface layer through the inlet passages and is
naturally channeled to an outlet passage. It is also apparent that
any other configuration of the manifold layer and interface layer
is alternatively used to allow the heat exchanger to operate in a
vertical position.
[0100] FIGS. 8A-8C illustrate top view diagrams of another
alternate embodiment of the heat exchanger in accordance with the
present invention. In particular, FIG. 8A illustrates a top view
diagram of an alternate manifold layer 206 in accordance with the
present invention. FIGS. 8B and 8C illustrate a top view of an
intermediate layer 204 and interface layer 202. In addition, FIG.
9A illustrates a three tier heat exchanger utilizing the alternate
manifold layer 206, whereas FIG. 9B illustrates a two-tier heat
exchanger utilizing the alternate manifold layer 206.
[0101] As shown in FIGS. 8A and 9A, the manifold layer 206 includes
a plurality of fluid ports 208 configured horizontally and
vertically. Alternatively, the fluid ports 208 are positioned
diagonally or in any other direction with respect to the manifold
layer 206. The fluid ports 208 are placed in selected locations in
the manifold layer 206 to effectively deliver fluid to the
predetermined interface hot spot regions in the heat exchanger 200.
The multiple fluid ports 208 provide a significant advantage,
because fluid can be directly delivered from a fluid port to a
particular interface hot spot region without significantly adding
to the pressure drop to the heat exchanger 200. In addition, the
fluid ports 208 are also positioned in the manifold layer 206 to
allow fluid in the interface hot spot regions to travel the least
amount of distance to the exit port 208 such that the fluid
achieves temperature uniformity while maintaining a minimal
pressure drop between the inlet and outlet ports 208. Additionally,
the use of the manifold layer 206 aids in stabilizing two phase
flow within the heat exchanger 200 while evenly distributing
uniform flow across the interface layer 202. It should be noted
that more than one manifold layer 206 is alternatively included in
the heat exchanger 200, whereby one manifold layer 206 routes the
fluid into and out-of the heat exchanger 200 and another manifold
layer (not shown) controls the rate of fluid circulation to the
heat exchanger 200. Alternatively, all of the plurality of manifold
layers 206 circulate fluid to selected corresponding interface hot
spot regions in the interface layer 202.
[0102] The alternate manifold layer 206 has lateral dimensions
which closely match the dimensions of the interface layer 202. In
addition, the manifold layer 206 has the same dimensions of the
heat source 99. Alternatively, the manifold layer 206 is larger
than the heat source 99. The vertical dimensions of the manifold
layer 206 are within the range of 0.1 and 10 millimeters. In
addition, the apertures in the manifold layer 206 which receive the
fluid ports 208 are within the range between 1 millimeter and the
entire width or length of the heat source 99.
[0103] FIG. 11 illustrates a broken-perspective view of a three
tier heat exchanger 200 having the alternate manifold layer 200 in
accordance with the present invention. As shown in FIG. 11, the
heat exchanger 200 is divided into separate regions dependent on
the amount of heat produced along the body of the heat source 99.
The divided regions are separated by the vertical intermediate
layer 204 and/or microchannel wall features 210 in the interface
layer 202. However, it is apparent to one skilled in the art that
the assembly shown in FIG. 11 is not limited to the configuration
shown and is for exemplary purposes. The heat exchanger 200 is
coupled to one or more pumps, whereby by one pump is coupled to the
inlets 208A and another pump is coupled to the inlet 208B.
[0104] As shown in FIG. 3, the heat source 99 has a hot spot in
location A and a warm spot, location B, whereby the hot spot in
location A produces more heat than the warm spot in location B. It
is apparent that the heat source 99 alternatively has more than one
hot spot and warm spot at any location at any given time. In the
example, since location A is a hot spot and more heat in location A
transfers to the interface layer 202 above location A (designated
in FIG. 11 as interface hot spot region A), more fluid and/or a
higher rate of liquid flow is provided to interface hot spot region
A in the heat exchanger 200 to adequately cool location A. It is
apparent that although interface hot spot region B is shown to be
larger than interface hot spot region A, interface hot spot regions
A and B, as well as any other interface hot spot regions in the
heat exchanger 200, can be any size and/or configuration with
respect to one another.
[0105] Alternatively, as shown in FIG. 11, the fluid enters the
heat exchanger via fluid ports 208A is directed to interface hot
spot region A by flowing along the intermediate layer 204 to the
inflow conduits 205A. The fluid then flows down the inflow conduits
205A in the Z-direction into interface hot spot region A of the
interface layer 202. The fluid flows in between the microchannels
210A whereby heat from location A transfers to the fluid by
conduction through the interface layer 202. The heated fluid flows
along the interface layer 202 in interface hot spot region A toward
exit port 209A where the fluid exits the heat exchanger 200. It is
apparent to one skilled in the art that any number of inlet ports
208 and exit ports 209 are utilized for a particular interface hot
spot region or a set of interface hot spot regions. In addition,
although the exit port 209A is shown near the interface layer 202A,
the exit port 209A is alternatively positioned in any other
location vertically, including but not limited to the manifold
layer 209B.
[0106] Similarly, in the example shown in FIG. 11, the heat source
99 has a warm spot in location B which produces less heat than
location A of the heat source 99. Fluid entering through the port
208B is directed to interface-hot spot region B by flowing along
the intermediate layer 204B to the inflow conduits 205B. The fluid
then flows down the inflow conduits 205B in the Z-direction into
interface hot spot region B of the interface layer 202. The fluid
flows in between the microchannels 210 in the X and Y directions,
whereby heat generated by the heat source in location B is
transferred into the fluid. The heated fluid flows along the entire
interface layer 202B in interface hot spot region B upward to exit
ports 209B in the Z-direction via the outflow conduits 205B in the
intermediate layer 204 whereby the fluid exits the heat exchanger
200.
[0107] Alternatively, as shown in FIG. 9A, the heat exchanger 200
alternatively includes a vapor permeable membrane 214 positioned
above the interface layer 202. The vapor permeable membrane 214 is
in sealable contact with the inner side walls of the heat exchanger
200. The membrane is configured to have several small apertures
which allow vapor produced along the interface layer 202 to pass
therethrough to the port 209. The membrane 214 is also configured
to be hydrophobic to prevent liquid fluid flowing along the
interface layer 202 from passing through the apertures of the
membrane 214. More details of the vapor permeable membrane 114 is
discussed in co-pending U.S. application Ser. No. 10/366,128, filed
Feb. 12, 2003 and entitled, "VAPOR ESCAPE MICROCHANNEL HEAT
EXCHANGER" which is hereby incorporated by reference.
[0108] FIG. 12A illustrates an exploded view of an alternative heat
exchanger 300 in accordance with the present invention. FIG. 12B
illustrates an exploded view of an alternative heat exchanger 300'
in accordance with the present invention. As shown in FIGS. 12A and
12B, the heat exchanger 300, 300' includes the interface layer 302,
302' and the manifold layer 306, 306' coupled thereto. As stated
above, the heat exchanger 300, 300' is coupled to the heat source
(not shown) or alternatively fully integrated within the heat
source (e.g. embedded in a microprocessor). It is apparent to one
skilled in the art that the interface layer 302, 302' is
substantially enclosed, and is only shown exposed in FIG. 12A for
exemplary purposes only. In one embodiment, the interface layer
302, 302' includes a plurality of pillars 303 disposed along the
bottom surface 301. In addition, the pillars 303 alternatively has
any shape, as discussed in relation to FIGS. 10A-10E and/or
radially distributed fins 303E. Again, the interface layer 302
alternatively has any other features as discussed above (e.g.
microchannels, roughened surfaces). The interface layer 302 as well
as the features within the layer 302 also has the same thermal
conductivity characteristics as discussed above. Although the
interface layer 302 is shown as smaller compared to the manifold
layer 306, it is apparent to one skilled in the art that the
interface layer 302 and manifold layer 306 can be any other size
with respect to each other and the heat source 99. The remaining
features of the interface layer 302, 302' has the same
characteristics as the interface layers described above and will
not be discussed in any more detail.
[0109] Generally, the heat exchanger 300 minimizes the pressure
drop within the heat exchanger using the delivery channels 322 in
the manifold layer 306. The delivery channels 322 are vertically
positioned within the manifold layer 306 and vertically provide
fluid to the interface layer 302 to reduce the pressure drop in the
heat exchanger 300. As stated above, pressure drop is created or
increased in the heat exchanger 300 due to fluid flowing along the
interface layer in the X and Y directions for a substantial amount
of time and/or distance. The manifold layer 306 minimizes the flow
in the X and Y directions by vertically forcing the fluid onto the
interface layer 302 by the several delivery channels 322. In other
words, several individual jets of fluid are applied directly onto
the interface layer 302 from above. The delivery channels 322 are
positioned an optimal distance from one another to allow fluid to
flow minimally in the X and Y directions and vertically upward out
of the interface layer 302. Therefore, the force of individual
fluid paths from the optimally positioned channels 322 naturally
cause the fluid to flow in an upward fluid path away from the
interface layer 302. In addition, the individual channels 322
maximize the division of fluid flow among the several channels 322
in the interface layer 302, thereby reducing the pressure drop in
the heat exchanger 300 while effectively cooling the heat source
99. In addition, the configuration of the heat exchanger 300 allows
the heat exchanger 300 to be smaller in size than other heat
exchangers, because fluid does not need to travel a large amount of
distance in the lateral X and Y directions to adequately cool the
heat source 99.
[0110] The manifold layer 306 shown in FIG. 12A includes two
individual levels. In particular, the manifold layer 306 includes a
level 308 and a level 312. The level 308 is coupled to the
interface layer 302 and the level 312. Although FIG. 12A
illustrates that the level 312 is positioned above the level 308,
it is contemplated by one skilled in the art that the level 308 is
alternatively positioned above the level 312. It is also apparent
to one skilled in the art that any number of levels are
alternatively implemented in accordance with the present
invention.
[0111] The alternative manifold layer 306' shown in FIG. 12B
includes three individual levels. In particular, the manifold layer
306' includes a circulation level 304', a level 308' and a level
312'. The circulation level 304' is coupled to the interface layer
302' as well as the level 308'. The level 308' is coupled to the
circulation level 304' and the level 312'. Although FIG. 12B
illustrates that the level 312' positioned above the level 308', it
is contemplated by one skilled in the art that the level 308' is
alternatively positioned above the level 312'. It is also apparent
to one skilled in the art that any number of levels are
alternatively implemented in accordance with the present
invention.
[0112] FIG. 12C illustrates a perspective view of the circulation
level 304' in accordance with the present invention. The
circulation level 304' includes a top surface 304A' and a bottom
surface 304B'. As shown in FIGS. 12B and 12C, the circulation level
304' includes several apertures 322' which extend therethrough. In
one embodiment, the openings of the apertures 322' are flush with
the bottom surface 304B'. Alternatively, the apertures 322' extend
beyond the bottom surface 304B' to apply fluid closer to the
interface layer 302'. In addition, the circulation level 304'
includes several apertures 324' which extend therethrough from the
top surface 304A' to the bottom surface 304B' as well as protrude
vertically as cylindrical protrusions in the Z-direction a
predetermined distance. It is apparent to one skilled in the art
that the apertures 322', 324' alternatively extend at an angle
through the circulation level and do not need to be completely
vertical. As stated above, in one embodiment, the interface layer
302' (FIG. 12B) is coupled to the bottom surface 304B' of the
circulation level 304'. Thus, fluid enters the interface layer 302'
by flowing only through the apertures 322' in the Z-direction and
exits the interface layer 302' by flowing only through the
apertures 324' in the Z-direction. As discussed below, fluid
entering the interface layer 302' via the apertures 322' is kept
separate from fluid exiting the interface layer 302' via the
apertures 324' through the circulation level 304'.
[0113] As shown in FIG. 12C, a portion of the apertures 324' have
cylindrical members extending from the top surface 304A' in the
Z-direction from the circulation level 304', such that fluid flows
through the apertures 324' directly to the corridor 326' in the
level 312' (FIGS. 12F and 12G). The cylindrical protrusions are
circular as in FIG. 12C, but alternatively has any other shape.
Along the interface layer 302', however, the fluid flows from each
aperture 322' to the adjacent apertures 324' in the lateral and
vertical directions. In one embodiment, the apertures 322' and the
apertures 324' are thermally insulated from one another so that
heat from the heated fluid exiting the interface layer 302' through
the manifold layer 306' does not propagate to the cooled fluid
flowing to the interface layer 302' through the manifold layer
306'.
[0114] FIG. 12D illustrates an alternative embodiment of the level
308 in accordance with the present invention. As shown in FIG. 12D,
the level 308 includes a top surface 308A and a bottom surface
308B. The bottom surface 308B of the level 308 is coupled directly
to the interface layer 302, as shown in FIG. 12A. The level 308
includes a recessed corridor 320 which includes several fluid
delivery channels 322 which deliver fluid to the interface layer
302. The recessed corridor 320 is in sealable contact with the
interface layer 302, wherein fluid exiting the interface layer 302
flows around and between the channels 322 in the corridor 320 and
out through the port 314. It should be noted that fluid exiting the
interface layer 302 does not enter the delivery channels 322.
[0115] FIG. 12E illustrates a perspective view of the underside of
alternative embodiment of the level 308' in accordance with the
present invention. The level 308' includes a top surface 308A' and
a bottom surface 308B', whereby the bottom surface of the level
308B' is coupled directly to the circulation level 304' (FIG. 12C).
The level 308' includes a port 314', a corridor 320' and a
plurality of apertures 322', 324' in the bottom surface 308B'. It
is apparent to one skilled in the art that the level 308' includes
any number of ports and corridors. The apertures 322', 324' in FIG.
12E are configured to face the circulation level 304'. In
particular, as shown in FIG. 12E, the apertures 322' direct fluid
entering the corridor 320' to flow into the interface layer 302',
whereas the apertures 324' direct fluid from the interface layer
302' to flow to the level 312'. The apertures 324' extend
completely through the corridor 320' in the level 308'. The
apertures 324' are individualized and separated, such that fluid
flowing through the apertures 324' does not mix or come into
contact with the fluid flowing through the cylinders associated
with the apertures 324'. The apertures 324' are also individualized
to ensure that fluid entering through each aperture 324' flows
along the fluid path provided by the aperture 324'. In one
embodiment, the apertures 324' are vertically configured.
Therefore, the fluid is channeled vertically through a substantial
portion of the manifold layer 306'. It is apparent that the same
applies to the apertures 322', especially in the case in which the
level is positioned between the interface layer and the level.
[0116] Although the apertures or holes 322 are shown as having the
same size, the apertures 322 can have different or varying
diameters along a length. For instance, the holes 322 closer to the
port 314 can have a smaller diameter to restrict fluid flow
therethrough. The smaller holes 322 thus force the fluid to flow
down the apertures 322 which are further away from the port 314.
This variation in the diameters in the holes 322 allow a more
uniform distribution of fluid into the interface layer 302. It is
apparent to one skilled in the art that the hole 322 diameters are
alternatively varied to address cooling in known interface hot spot
regions in the interface layer 302. It is apparent to one skilled
in the art that the above discussion is applicable to the apertures
324', whereby the dimensions of the apertures 324' vary or are
different to accommodate uniform outflow from the interface layer
302.
[0117] In the alternative embodiment, the port 314 provides fluid
to the level 308 and to the interface layer 302. The port 314 in
FIG. 12D extends from the top surface 308A through a portion of the
body of the level 308 to the corridor 320. Alternatively, the port
314 extends to the corridor 320 from the side or the bottom of the
level 308. In one embodiment, the port 314 is coupled to the port
315 in the level 312 (FIGS. 12A-12B). The port 314 leads to the
corridor 320 which is enclosed, as shown in FIG. 12C, or recessed,
as in FIG. 12D. The corridor 320 serves to channel fluid to the
port 314 from the interface layer 302. The corridor 320
alternatively channels fluid from the port 314 to the interface
layer 302.
[0118] As shown in FIGS. 12F and 12G, the port 315 in the level 312
is aligned with and in communication with the port 314. In relation
to FIG. 12A, fluid enters the heat exchanger 300 via port 316 and
flows through the corridor 328 down to the delivery channels 322 in
the level 308 eventually to the interface layer 302. In relation to
FIG. 12B, fluid alternatively enters the heat exchanger 300' enters
via the port 315' and flows through the port 314' in the level 308'
and eventually to the interface layer 302'. The port 315 in FIG.
12F extends from the top surface 312A through the body of the level
312. Alternatively, the port 315 extends from a side of the level
312. Alternatively, the level 312 does not include the port 315,
whereby the fluid enters the heat exchanger 300 via the port 314
(FIGS. 12D and 12E). In addition, the level 312 includes a port 316
which channels the fluid to the corridor 328'. It is apparent to
one skilled in the art that the level includes any number of ports
and corridors. The corridor 328 channels fluid to the delivery
channels 322 and eventually to the interface layer 302.
[0119] FIG. 12G illustrates a perspective underside view of an
alternative embodiment of the level 312' in accordance with the
present invention. The level 312' is coupled to the level 308' in
FIG. 12E. As shown in FIG. 12F, the level 312' includes a recessed
corridor area 328' within the body which is exposed along the
bottom surface 312B'. The recessed corridor 328' is in
communication with the port 316', whereby fluid travels directly
from the recessed corridor 328' to the port 316'. The recessed
corridor 328' is positioned above the top surface 308A' of the
level 308' to allow fluid to freely travel upward from the
apertures 324' to the corridor 328'. The perimeter of the recessed
corridor 320' and bottom surface 312B' is sealed against the top
surface 308A' of the level 312' such that all of the fluid from the
apertures 324' flows to the port 316' via the corridor 328'. Each
of the apertures 330' in the bottom surface 312B' is aligned with
and in communication with a corresponding aperture 321' in the
level 308' (FIG. 12E), whereby the apertures 330' are positioned
flush with the top surface 308A' of the level 308' (FIG. 12E).
Alternatively, the apertures 330 have a diameter slightly larger
than the diameter of the corresponding aperture 324', whereby the
apertures 324' extend through the apertures 330' into the corridor
328'.
[0120] FIG. 12H illustrates a cross sectional view of the heat
exchanger in FIG. 12A along lines H-H in accordance with the
present invention. As shown in FIG. 12H, the interface layer 302 is
coupled to a heat source 99. As stated above, the heat exchanger
300 is alternatively integrally formed with the heat source 99 as
one component. The interface layer 302 is coupled to the bottom
surface 308B of the level 308. In addition, the level 312 is
coupled to the level 308, whereby the top surface 308A of the level
308 is sealed against the bottom surface 312B of the level 312. The
perimeter of the corridor 320 of the level 308 is in communication
with the interface layer 302. In addition, the corridor 328 in the
level 312 is in communication with the apertures 322 in the level
308. The bottom surface 312B of the level 312 is sealed against the
top surface 308A of the level 308 such that fluid does not leak
between the two levels 308, 312.
[0121] FIG. 12I illustrates a cross sectional view of the
alternative heat exchanger in FIG. 12B along lines I-I in
accordance with the present invention. As shown in FIG. 12I, the
interface layer 302' is coupled to a heat source 99'. The interface
layer 302' is coupled to the bottom surface 304B' of the
circulation level 304'. Also, the circulation level 304 is coupled
to the level 308', whereby the top surface 304A' of the circulation
level 304' is sealed against the bottom surface 308B' of the level
308'. In addition, the level 312' is coupled to the level 308',
whereby the top surface 308A' of the level 308' is sealed against
the bottom surface 312B' of the level 312'. The perimeter of the
corridor 320' of the level 308' is in communication with the
apertures in the top surface 304A' of the circulation level 304'
such that fluid does not leak between the two levels. In addition,
the perimeter of the corridor 328' in the level 312' is in
communication with the apertures in the top surface 308A' of the
circulation level 308' such that fluid does not leak between the
two levels.
[0122] In the operation of the heat exchanger 300, as shown by the
arrows in FIGS. 12A and 12H, cooled fluid enters the heat exchanger
300 through the port 316 in the level 312'. The cooled fluid
travels down the port 316 to the corridor 328 and flows downward to
the interface layer 302 via the delivery channels 322. The cooled
fluid in the corridor 320 does not mix or come into contact with
any heated fluid exiting the heat exchanger 300. The fluid entering
the interface layer 302 undergoes thermal exchange with and absorbs
the heat produced in the heat source 99. The apertures 322 are
optimally arranged such that the fluid travels the least amount of
distance in the X and Y direction in the interface-layer 302 to
minimize the pressure drop in the heat exchanger 300 while
effectively cooling the heat source 99. The heated fluid then
travels upward in the Z-direction from the interface layer 302 to
the corridor 320 in the level 308. The heated fluid exiting the
manifold layer 306 does not mix or come into contact with any
cooled fluid entering the manifold layer 306. The heated fluid,
upon entering the corridor 320 flows to the ports 314 and 315 and
exits the heat exchanger 300. It is apparent to one skilled in the
art that the fluid alternatively flows opposite the way shown in
FIGS. 12A and 12H without departing from the scope of the present
invention.
[0123] In the alternative operation, as shown by the arrows in
FIGS. 12B and 12I, cooled fluid enters the heat exchanger 300'
through the port 316' in the level 312'. The cooled fluid travels
down the port 315' to the port 314' in the level 308'. The fluid
then flows into the corridor 320' and flows downward to the
interface layer 302' via the apertures 322' in the circulation
level 304'. However, the cooled fluid in the corridor 320' does not
mix or come into contact with any heated fluid exiting the heat
exchanger 300'. The fluid entering the interface layer 302'
undergoes thermal exchange with and absorbs the heat produced in
the heat source 99. As discussed below, the apertures 322' and
apertures 324' are arranged such that the fluid travels the optimal
closest distance along the interface layer 302' from each aperture
322' to an adjacent aperture 324' to reduce the pressure drop
therebetween while effectively cooling the heat source 99. The
heated fluid then travels upward in the Z-direction from the
interface layer 302' through the level 308' via the several
apertures 324' to the corridor 328' in the level 312'. The heated
fluid does not mix or come into contact with any cooled fluid
entering the manifold layer 306' as it travels up the apertures
324'. The heated fluid, upon entering the corridor 328' in the
level 312' flows to the port 316' and exits the heat exchanger
300'. It is apparent to one skilled in the art that the fluid
alternatively flows opposite the way shown in FIGS. 12B and 12I
without departing from the scope of the present invention.
[0124] In the manifold layer 306, the apertures 322 are arranged
such that the distance which the fluid flows in the interface layer
302 is minimized while adequately cooling the heat source 99. In
the alternative manifold layer 306', the apertures 322' and
apertures 324' are arranged such that the distance which the fluid
flows in the interface layer 302' is minimized while adequately
cooling the heat source 99. Specifically, the and apertures 322',
324' provide substantially vertical fluid paths, such that the flow
is minimize in the X and Y lateral directions in the heat exchanger
300'. Thus, the heat exchanger 300, 300' greatly reduces the
distance that the fluid must flow to adequately cool the heat
source 99, which in turn, greatly reduces the pressure drop
generated within the heat exchanger 300, 300' and system 30, 30'
(FIGS. 2A-2B). The specific arrangement and cross-sectional sizes
of the apertures 322 and/or apertures 324 depend on a variety of
factors, including, but not limited to, flow conditions,
temperature, heat generated by the heat source 99 and fluid
flow-rate. It is noted that although the following discussion
relates to apertures 322 and 324, it is apparent that the
discussion also applies to only apertures 322 or apertures 324.
[0125] The apertures 322, 324 are spaced apart from each other an
optimal distance whereby the pressure drop is minimized as the heat
source 99 is adequately cooled to a desired temperature. The
arrangement and optimal distance of the apertures 322 and/or
apertures 324 in the embodiment also allows independent
optimization of the apertures 322, 324 and fluid paths, in general,
through the interface layer 302 by changing the dimensions and
locations of the individual apertures. In addition, the arrangement
of the apertures in the embodiment also significantly increases the
division of total flow entering the interface layer as well as the
amount of area cooled by the fluid entering through each aperture
322.
[0126] In one embodiment, the apertures 322, 324 are disposed in an
alternating configuration or a `checkerboard` pattern in the
manifold layer 306, as shown in FIGS. 13 and 14. Each of the
apertures 322, 324 are separated by the least amount of distance
that the fluid must travel in the checkerboard pattern. However,
the apertures 322, 324 must be separated a distance large enough
from each other to provide the cooling liquid to the interface
layer 302 for a sufficient amount of time. As shown in FIGS. 13 and
14, one or more of the apertures 322 are disposed adjacent to a
corresponding number of apertures or vice versa such that the fluid
entering the interface layer 302 travels the least amount of
distance along the interface layer 302 before exiting the interface
layer 302. Thus, as shown in the figures, the apertures 322, 324
are radially distributed around each other to assist the fluid in
traveling the least amount of distance from any aperture 322 to the
closest aperture 324. For example, as shown in FIG. 13, fluid
entering the interface layer 302 via one specific aperture 322
experiences the path of least resistance to an adjacent aperture
324. In addition, the apertures 322, 324 are circular in shape,
although the apertures can have any other shape.
[0127] In addition, as stated above, although the apertures 324
shown in the figures protrude from the circulation level 304 or
level 308, 312 as a cylindrical member, the apertures alternatively
do not protrude from any of the levels in the manifold layer 306.
The manifold layer 306 has rounded surfaces around the areas where
fluid changes direction to aid in reducing the pressure drop in the
heat exchanger 300.
[0128] The optimal distance configuration as well as the dimensions
of the apertures 322, 324 depend on the amount of temperature that
the fluid is exposed to along the interface layer 302. It is also
important that the cross sectional dimensions for the fluid paths
in the apertures 322, 324 are large enough to reduce pressure drop
in the heat exchanger 300. For the case in which fluid experiences
only single-phase flow along the interface layer 302, each aperture
322 is surrounded by several adjacent apertures 324 in a
symmetrical hexagonal arrangement, as shown in FIG. 13. In
addition, for single-phase flow, the number of apertures are
approximately equal in the circulation level 304. Additionally, for
single-phase flow, the apertures 322, 324 are the same diameter. It
is apparent to one skilled in the art that other arrangements as
well as any ratio of apertures 322, 324 are alternatively
contemplated.
[0129] For the case in which the fluid experiences two-phase flow
along the interface layer 302, non-symmetric arrangements of the
apertures 322, 324 are used to accommodate acceleration of the
two-phase fluid. However, symmetric arrangements of the apertures
322, 324 are also contemplated for two-phase flow. For instance,
the apertures 322, 324 can be symmetrically arranged in the
circulation level 304, whereby the apertures 324 have larger
openings than the apertures 322. Alternatively, the hexagonal
symmetrical arrangement shown in FIG. 13 are used in the
circulation level 304 for two-phase flow, whereby more apertures
324 are present in the circulation level 304 than apertures
322.
[0130] It is should be noted that the apertures 322, 324 in the
circulation level can alternatively be arranged to cool hot spots
in the heat source 99. Thus, for example, two apertures 322 are
alternatively positioned immediately next to each other in the
circulation level 304, whereby both apertures 322 are positioned
near or above an interface hot spot region. It is apparent that the
appropriate number of apertures 324 are positioned adjacent to both
apertures 322 to reduce the pressure drop in the interface layer
302. Therefore, the two apertures 322 supply cool fluid to the
interface hot spot region to compel the interface hot spot region,
discussed above, to be a uniform, substantially equal
temperature.
[0131] As stated above, the heat exchanger 300 has significant
advantages over other heat exchangers. The configuration of the
heat exchanger 300 is alternatively utilized with a
modest-performance pump due to the reduction of pressure drop
caused by the vertical fluid paths. In addition, the configuration
of the heat exchanger 300 allows independent optimization of the
inlet, and fluid paths along the interface layer 302. Additionally,
the separate levels allow a customizable design foundation to
optimize the uniformity of heat transfer, reduction of pressure
drop and dimensions of the individual components therein. The
configuration of the heat exchanger 300 also reduces the pressure
drop in systems in which the fluid undergoes two phase flow and
thereby can be used in single phase and two phase systems. Further,
as discussed below, the heat exchanger accommodates many different
manufacturing methods and allows adjustment of component geometry
for tolerance purposes.
[0132] FIG. 18 illustrates a perspective view of the heat exchanger
of the preferred embodiment of the present invention. As shown in
FIG. 18, the heat exchanger 600 includes a bottom manifold layer
604, an interface layer 602 and a top manifold layer 606. The top
manifold layer 606 is coupled to the bottom manifold layer 604,
whereby the interface layer 602 is positioned in between the top
and bottom manifold layers 604, 606. As shown in FIGS. 18 and 19,
the top manifold layer 606 preferably includes two apertures 608,
609 which extend therethrough. In particular, the inlet aperture
608 channels preferably cooled fluid into the heat exchanger 600
and the outlet aperture 609 channels warm or hot fluid from the
heat exchanger 600. It should be noted that although one inlet and
outlet aperture 608, 609 is shown in FIGS. 18 and 19, any number of
inlet and outlet apertures 608, 609 are alternatively contemplated.
In addition, although the inlet and outlet apertures 608, 609 are
shown to be vertically configured in the top manifold 606, the
apertures 608, 609 are alternatively configured horizontally and/or
diagonally. In addition, the top manifold 606 includes several
outlet fluid channels 610 which are in communication with the
outlet chamber 612 and the outlet aperture 609. Although the fluid
channels 610 show in FIG. 19 are straight and parallel to one
another, it is contemplated that the fluid channels 610 are
alternatively configured in any pattern and have any appropriate
shape.
[0133] The bottom manifold layer 604 includes a top surface 614
which mates to the bottom surface 615 (FIG. 19) of the top manifold
606. The bottom manifold layer 604 includes a recess area 616 from
the top surface 614 into the body of the bottom manifold layer 604.
The recess 616 has an appropriate depth to accept the interface
layer 602, whereby the interface layer 602 is preferably flush with
the top surface 615 when coupled to the bottom manifold layer 604,
as shown in FIG. 20. As shown in FIG. 18, the recess area 616
includes a raised surface 620 having several fluid channels 618
configured in parallel with one another in the raised surface 620.
The raised surface 620 protrudes upward from the bottom surface of
the recess area 616 an appropriate distance such that the bottom
surface of the interface layer 602 is in contact with the raised
surface 620. The bottom manifold layer 604 as well as the raised
surface 620 is made of a material having a high thermal
conductivity, such that heat generated by the heat source 99
transfers directly through the raised surface 620 to the interface
layer 602. In addition, fluid within the recess area 616 flows
along the fluid channels 618 through the raised surface 620 and
absorbs the heat in the recessed area 616, wherein the temperature
of the fluid increases due to thermal exchange in the recess area
616.
[0134] The higher temperature fluid flows from the fluid channels
618 to the interface layer 602. The interface layer 602 passes the
fluid from the recess area 616 in the bottom manifold layer 604 to
the fluid channels 610 (FIG. 19) in the top manifold layer 602. The
interface layer 602 is also in contact with the raised conductive
surface 620 of the bottom manifold layer 604. The interface layer
602 provides a thermal exchange environment where the fluid is able
to adequately absorb the heat from the heat source 99. Thus, the
interface layer 602 is preferably a microporous structure as
discussed above, whereby the interface layer 602 has a high surface
volume characteristic. Alternatively, the interface layer 602
includes microchannels (not shown), pillars (not shown) or any
combination thereof.
[0135] It should be noted that although FIGS. 18-20 illustrate that
fluid enters and exits the heat exchanger 600 via the top manifold
layer 606, the fluid alternatively enters and exits through the
bottom manifold layer 604 or a combination of the top and bottom
manifold layers 604, 606. For example, in an alternative
embodiment, the fluid enters the heat exchanger 600 from underneath
the bottom manifold layer 604, whereby the fluid exits the heat
exchanger 600 via the aperture 609 in the top manifold layer
606.
[0136] The operation of the preferred heat exchanger 600 will now
be discussed in relation to FIGS. 18-20. In the preferred
embodiment, the cooled fluid enters the heat exchanger 600 via the
inlet port 608. As stated above, the bottom surface 615 of the top
manifold layer 606 is mated in contact with the top surface 614 of
the bottom manifold layer 604. Thus, the fluid flows in the Z
direction directly from the top manifold layer 606 to the recess
area 616 in the bottom manifold layer 604. Upon reaching the recess
area 616, the fluid travels in the X direction along the recess
area 616 toward the fluid grooves 618 which are disposed within the
raised heat exchange surface 620. In regard to FIG. 20, the
interface layer 602 is positioned in contact with the raised heat
exchange surface 620, whereby heat is transferred from the raised
heat exchange surface 620 to the interface layer 602. As stated
above, the raised heat exchange surface 620 as well as the bottom
manifold layer 604 itself have an appropriate thermal conductivity
to allow sufficient heat transfer to occur from the heat source 99
to the interface layer 602. Therefore, the heat from the heat
source 99 conducts to the interface layer 602, whereby the cooled
fluid travels through the fluid grooves 618 and performs some
thermal exchange with the heated raised heat exchange surface 620.
The fluid travels from the fluid grooves 618 in the Z direction to
the interface layer 602, whereby the fluid further performs thermal
exchange with the interface layer 602. As stated above, the
interface layer 602 is preferably a microporous structure which has
a large surface to volume characteristic which absorbs the fluid
and heat from the bottom surface manifold 604 to allow the fluid to
sufficiently remove the heat from the heat source 99. The heated
fluid then flows along the fluid channels 610 to the outlet chamber
612 and exits the heat exchanger 606 via the outlet port 609.
[0137] The details of how the heat exchanger 100 as well as the
individual layers in the heat exchanger 100 are fabricated and
manufactured are discussed below. The following discussion applies
to the preferred and alternative heat exchangers of the present
invention, although the heat exchanger 100 in FIG. 3B and
individual layers therein are expressly referred to for simplicity.
It is also apparent to one skilled in the art that although the
fabrication/manufacturing details are described in relation to the
present invention, the fabrication and manufacturing details also
alternatively apply to conventional heat exchangers as well as two
and three-tier heat exchangers utilizing one fluid inlet port and
one fluid port as shown in FIGS. 1A-1C.
[0138] Preferably, the interface layer has a coefficient of thermal
expansion (CTE) which is approximate or equal to that of the heat
source 99. Thus, the interface layer preferably expands and
contracts accordingly with the heat source 99. Alternatively, the
material of the interface layer 302 has a CTE which is different
than the CTE of the heat source material. An interface layer 302
made from a material such as Silicon has a CTE that matches that of
the heat source 99 and has sufficient thermal conductivity to
adequately transfer heat from the heat source 99 to the fluid.
However, other materials are alternatively used in the interface
layer 302 which have CTEs that match the heat source 99.
[0139] The interface layer preferably has a high thermal
conductivity for allowing sufficient conduction to pass between the
heat source 99 and fluid flowing along the interface layer 302 such
that the heat source 99 does not overheat. The interface layer is
preferably made from a material having a high thermal conductivity
of 100 W/m-K. However, it is apparent to one skilled in the art
that the interface layer 302 has a thermal conductivity of more or
less than 100 W/m-K and is not limited thereto.
[0140] To achieve the preferred high thermal conductivity, the
interface layer is preferably made from a semiconductor substrate,
such as Silicon. Alternatively, the interface layer is made from
any other material including, but not limited to single-crystalline
dielectric materials, metals, aluminum, nickel and copper, Kovar,
graphite, diamond, composites and any appropriate alloys. An
alternative material of the interface layer 302 is a patterned or
molded organic mesh.
[0141] As shown in FIG. 15, it is preferred that the interface
layer is coated with a coating layer 112 to protect the material of
the interface layer as well as enhance the thermal exchange
properties of the interface layer. In particular, the coating 112
provides chemical protection that eliminates certain chemical
interactions between the fluid and the interface layer 302. For
example, an interface layer 302 made from aluminum is etched by the
fluid coming into contact with it, whereby the interface layer 102
would deteriorate over time. The coating 112 of a thin layer of
Nickel, approximately 25 microns, is thus electroplated over the
surface of the interface layer 302 to chemically pacify any
potential reactions without significantly altering the thermal
properties of the interface layer 302. It is apparent that any
other coating material with appropriate layer thickness is
contemplated depending on the material(s) in the interface layer
302.
[0142] The interface layer 302 is formed by an etching process
using a Copper material coated with a thin layer of Nickel to
protect the interface layer 302. Alternatively, the interface layer
302 is made from Aluminum, Silicon substrate, plastic or any other
appropriate material. The interface layer 302 being made of
materials having poor thermal conductivity are also coated with the
appropriate coating material to enhance the thermal conductivity of
the interface layer 302. One method of electroforming the interface
layer is by applying a seed layer of chromium or other appropriate
material along the bottom surface of the interface layer 302 and
applying electrical connection of appropriate voltage to the seed
layer. The electrical connection thereby forms a layer of the
thermally conductive coating material 112 on top of the interface
layer 302. The electroforming process also forms feature dimensions
in a range of 10-100 microns. The interface layer 302 is formed by
an electroforming process, such as patterned electroplating. In
addition, the interface layer is alternatively processed by
photochemical etching or chemical milling, alone or in combination,
with the electroforming process. Standard lithography sets for
chemical milling are used to process features in the interface
layer 302. Additionally, the aspect ratios and tolerances are
enhanceable using laser assisted chemical milling processes.
[0143] The pillars 303 discussed above are manufactured a variety
of methods. However, it should be noted that the pillars 303 are
manufactured to have a high thermal conductivity. In one
embodiment, the pillars 303 are made with a highly conductive
material such as Copper. However, other materials, such as Silicon
are contemplated by one skilled in the art. The pillars 303 are
manufactured by various means including, but not limited to,
electroforming, EDM wire manufacturing, stamping, MIN and
machining. In addition, cross-cutting with saws and/or milling
tools can also produce the desired configuration in the interface
layer 302. For an interface layer 302 made of Silicon, the pillars
303 would be manufactured by methods such as plasma etching,
sawing, lithographic patterning and various wet etching depending
on the desired aspect ratio of pillars 303 in the interface layer
302. The radially distributed rectangular fins 303E (FIG. 10E) can
be manufactured by lithographic patterning whereby plasma etching
or electroplating methods are employed within the lithographically
defined molds.
[0144] In the alternative embodiment, microchannel walls 110 used
in the interface layer 102 are made of Silicon. The microchannel
walls 110 are alternatively made of any other materials including,
but not limited to, patterned glass, polymer, and a molded polymer
mesh. Although the microchannel walls 110 are made from the same
material as that of the bottom surface 103 of the interface layer
102, the microchannel walls 110 are alternatively made from a
different material than that of the rest of the interface layer
102.
[0145] In the alternative embodiment, the microchannel walls 110
have thermal conductivity characteristics of at least 10 W/m-K.
Alternatively, the microchannel walls 110 have thermal conductivity
characteristics of more than 10 W/m-K. It is apparent to one
skilled in the art that the microchannel walls 110 alternatively
have thermal conductivity characteristics of less than 10 W/m-K,
whereby coating material 112 is applied to the microchannel walls
110, as shown in FIG. 15, to increase the thermal conductivity of
the wall features 110. For microchannel walls 110 made from
materials already having a good thermal conductivity, the coating
112 applied has a thickness of at least 25 microns which also
protects the surface of the microchannel walls 110. For
microchannel walls 110 made from material having poor thermal
conductivity characteristics, the coating 112 has a thermal
conductivity of at least 50 W/m-K and is more than 25 microns
thick. It is apparent to one skilled in the art that other types of
coating materials as well as thickness dimensions are
contemplated.
[0146] To configure the microchannel walls 110 to have an adequate
thermal conductivity of at least 10 W/m-K, the walls 110 are
electroformed with the coating material 112 (FIG. 15), such as
Nickel or other metal, as discussed above. To configure the
microchannel walls 110 to have an adequate thermal conductivity of
at least 50 W/m-K, the walls 110 are electroplated with Copper on a
thin metal film seed layer. Alternatively, the microchannel walls
110 are not coated with the coating material.
[0147] The microchannel walls 110 are formed by a hot embossing
technique to achieve a high aspect ratio of channel walls 110 along
the bottom surface 103 of the interface layer 102. The microchannel
wall features 110 are alternatively fabricated as Silicon
structures deposited on a glass surface, whereby the features are
etched on the glass in the desired configuration. The microchannel
walls 110 are alternatively formed by a standard lithography
techniques, stamping or forging processes, or any other appropriate
method. The microchannel walls 110 are alternatively made
separately from the interface layer 102 and coupled to the
interface layer 102 by anodic or epoxy bonding. Alternatively, the
microchannel features 110 are coupled to the interface layer 102 by
conventional electroforming techniques, such as electroplating.
[0148] There are a variety of methods that can be used to fabricate
the intermediate layer 104. The intermediate layer is made from
Silicon. It is-apparent to one skilled in the art that any other
appropriate material is contemplated including, but not limited to
glass, laser-patterned glass, polymers, metals, glass, plastic,
molded organic material or any composites thereof. Alternatively,
the intermediate layer 104 is formed using plasma etching
techniques. Alternatively, the intermediate layer 104 is formed
using a chemical etching technique. Other alternative methods
include machining, etching, extruding and/or forging a metal into
the desired configuration. The intermediate layer 104 is
alternatively formed by injection molding of a plastic mesh into
the desired configuration. Alternatively, the intermediate layer
104 is formed by laser-drilling a glass plate into the desired
configuration.
[0149] The manifold layer 306 is manufactured by a variety of
methods. In one embodiment, the manifold layer 306 is manufactured
as one entire piece. Alternatively, the manifold layer 306 is
manufactured as separate components shown in FIG. 12 which are then
coupled together. The manifold layer 306 can be fabricated is an
injection molding process utilizing plastic, metal, polymer
composite or any other appropriate material, whereby each layer is
made from the same material. Alternatively, as discussed above,
each layer is made from a different material. The manifold layer
306 is alternatively generated using a machined or etched metal
technique. It is apparent to one skilled in the art that the
manifold layer 306 is manufactured utilizing any other appropriate
method.
[0150] The intermediate layer 104 is coupled to the interface layer
102 and manifold layer 106 to form the heat exchanger 100 using a
variety of methods. The interface layer 102, intermediate layer 104
and manifold layer 106 are coupled to one another by an anodic,
adhesive or eutectic bonding process. The intermediate layer 104 is
alternatively integrated within features of the manifold layer 106
and interface layer 102. The intermediate layer 104 is coupled to
the interface layer 102 by a chemical bonding process. The
intermediate layer 104 is alternatively manufactured by a hot
embossing or soft lithography technique, whereby a wire EDM or
Silicon master is utilized to stamp the intermediate layer 104. The
intermediate layer 104 is then alternatively electroplated with
metal or another appropriate material to enhance the thermal
conductivity of the intermediate layer 104, if needed.
[0151] Alternatively, the intermediate layer 104 is formed along
with the fabrication of the microchannel walls 110 in the interface
layer 102 by an injection molding process. Alternatively, the
intermediate layer 104 is formed with the fabrication of the
microchannel walls 110 by any other appropriate method. Other
methods of forming the heat exchanger include, but are not limited
to soldering, fusion bonding, eutectic Bonding, intermetallic
bonding, and any other appropriate technique, depending on the
types of materials used in each layer.
[0152] Another alternative method of manufacturing the heat
exchanger of the present invention is described in FIG. 16. As
discussed in relation to FIG. 16, an alternative method of
manufacturing the heat exchanger includes building a hard mask
formed from a silicon substrate as the interface layer (step 500).
The hard mask is made from silicon dioxide or alternatively
spin-on-glass. Once the hard mask is formed, a plurality of
under-channels are formed in the hard mask, wherein the
under-channels form the fluid paths between the microchannel walls
110 (step 502). The under-channels are formed by any appropriate
method, including but not limited to HF etching techniques,
chemical milling, soft lithography and xenon difluoride etch. In
addition, enough space between each under-channel must be ensured
such that under-channels next to one another do not bridge
together. Thereafter, spin-on-glass is then applied by any
conventional method over the top surface of the hard mask to form
the intermediate and manifold layers (step 504). Following, the
intermediate and manifold layers are hardened by a curing method
(step 506). Once the intermediate and manifold layers are fully
formed and hardened, one or more fluid ports are formed into the
hardened layer (step 508). The fluid ports are etched or
alternatively drilled into the manifold layer. Although specific
methods of fabricating the interface layer 102, the intermediate
layer 104 and manifold layer 106 are discussed herein, other known
methods known in art to manufacture the heat exchanger 100 are
alternatively contemplated.
[0153] FIG. 17 illustrates an alternative embodiment of the heat
exchanger of the present invention. As shown in FIG. 6, two heat
exchangers 200, 200' are coupled to one heat source 99. In
particular, the heat source 99, such as an electronic device, is
coupled to a circuit board 96 and is positioned upright, whereby
each side of the heat source 99 is potentially exposed. A heat
exchanger of the present invention is coupled to one exposed side
of the heat source 99, whereby both heat exchangers 200, 200'
provide maximum cooling of the heat source 99. Alternatively, the
heat source is coupled to the circuit board horizontally, whereby
more than one heat exchanger is stacked on top of the heat source
99 (not shown), whereby each heat exchanger is electrically coupled
to the heat source 99. More details regarding this embodiment are
shown and described in co-pending U.S. patent application Ser. No.
10/072,137, filed Feb. 7, 2002, entitled "POWER CONDITIONING
MODULE" which is hereby incorporated by reference.
[0154] As shown in FIG. 17, the heat exchanger 200 having two
layers is coupled to the left side of the heat source 99 and the
heat exchanger 200' having three layers is coupled to the right
side of the heat source 99. It is apparent to one skilled in the
art that the heat exchangers are coupled to the sides of the heat
source 99. It is also apparent to one skilled in the art that the
alternative embodiments of the heat exchanger 200' are
alternatively coupled to the sides of the heat source 99. The
alternative embodiment shown in FIG. 17 allows more precise hot
spot cooling of the heat source 99 by applying fluid to cool hot
spots which exist along the thickness of the heat source 99. Thus,
the embodiment in FIG. 17 applies adequate cooling to hot spots in
the center of the heat source 99 by exchanging heat from both sides
of the heat source 99. It is apparent to one skilled in the art
that the embodiment shown in FIG. 17 is used with the cooling
system 30 in FIGS. 2A-2B, although other closed loop systems are
contemplated.
[0155] As stated above, the heat source 99 alternatively has
characteristics in which the locations of one or more of the hot
spots change due to different tasks required to be performed by the
heat source 99. To adequately cool the heat source 99, the system
30 alternatively includes a sensing and control module 34 (FIGS.
2A-2B) which dynamically changes the amount of flow and/or flow
rate of fluid entering the heat exchanger 100 in response to a
change in location of the hot spots.
[0156] In particular, as shown in FIG. 17, one or more sensors 124
are placed in each interface hot spot region in the heat exchanger
200 and/or alternatively the heat source 99 at each potential hot
spot location. Alternatively, a plurality of heat sources are
uniformly placed in between the heat source and heat exchanger
and/or in the heat exchanger itself. The control module 38 (FIG.
2A-2B) is also coupled to one or more valves in the loop 30 which
control the flow of fluid to the heat exchanger 100. The one or
more valves are positioned within the fluid lines, but are
alternatively positioned elsewhere. The plurality of sensors 124
are coupled to the control module 34, whereby the control module 34
is preferably placed upstream from heat exchanger 100, as shown in
FIG. 2. Alternatively, the control module 34 is placed at any other
location in the closed loop system 30.
[0157] The sensors 124 provide information to the control module 34
including, but not limited to, the flow rate of fluid flowing in
the interface hot spot region, temperature of the interface layer
102 in the interface hot spot region and/or heat source 99 and
temperature of the fluid. For example, referring to the schematic
in FIG. 17, sensors positioned on the interface 124 provide
information to the control module 34 that the temperature in a
particular interface hot spot region in heat exchanger 200 is
increasing whereas the temperature in a particular interface hot
spot region in heat exchanger 200' is decreasing. In response, the
control module 34 increases the amount of flow to heat exchanger
200 and decreases the amount of flow provided to heat exchanger
200'. Alternatively, the control module 34 alternatively changes
the amount of flow to one or more interface hot spot regions in one
or more heat exchangers in response to the information received
from the sensors 118. Although the sensors 118 are shown with the
two heat exchangers 200, 200' in FIG. 17, it is apparent that the
sensors 118 are alternatively coupled with only one heat
exchanger.
[0158] In an alternative embodiment, the heat exchanger 100 of the
present invention is coupled to a thermoelectric device 97, as
shown in FIG. 2A, whereby the thermoelectric device 97 is coupled
to the heat source 99. The thermoelectric device 97 has the same
dimensions of the heat source 99 and is coupled to a power source
96 which operates the thermoelectric device 97. The thermoelectric
device 97 serves to depress the junction temperature below the
hottest surface of the heat exchanger 100 and is alternatively used
to reduce temperature differences across the heat source 99. The
thermoelectric device 97 is alternatively utilized to aid in
cooling one or more hot spots in the heat source 99. In one
embodiment, the thermoelectric device 97 is formed integrally
within the heat exchanger 100 as part of the interface layer 102.
In another embodiment, the thermoelectric device 97 is formed
integrally within the heat source or microprocessor 99. It is
apparent to one skilled in the art that the thermoelectric device
97 is of any conventional type thermoelectric device 97 appropriate
for use with the heat source 99 and heat exchanger 100. It is also
apparent to one skilled in the art that the thermoelectric device
97 is utilized with any of the heat exchangers discussed and
described in the present application.
[0159] The present invention has been described in terms of
specific embodiments incorporating details to facilitate the
understanding of the principles of construction and operation of
the invention. Such reference herein to specific embodiments and
details thereof is not intended to limit the scope of the claims
appended hereto. It will be apparent to those skilled in the art
that modifications may be made in the embodiment chosen for
illustration without departing from the spirit and scope of the
invention.
* * * * *