U.S. patent application number 11/958114 was filed with the patent office on 2009-06-18 for cooling systems and heat exchangers for cooling computer components.
Invention is credited to Alexander I. Yatskov.
Application Number | 20090154091 11/958114 |
Document ID | / |
Family ID | 40752923 |
Filed Date | 2009-06-18 |
United States Patent
Application |
20090154091 |
Kind Code |
A1 |
Yatskov; Alexander I. |
June 18, 2009 |
COOLING SYSTEMS AND HEAT EXCHANGERS FOR COOLING COMPUTER
COMPONENTS
Abstract
Computer systems having heat exchangers for cooling computer
components are disclosed herein. The computer systems include a
computer cabinet having an air inlet, an air outlet spaced apart
from the air inlet, and a plurality of computer module compartments
positioned between the air inlet and the air outlet. The air inlet,
the air outlet, and the computer module compartments define an air
flow path through the computer cabinet. The computer systems also
include a heat exchanger positioned between two adjacent computer
module compartments. The heat exchanger includes a plurality of
heat exchange elements canted relative to the air flow path.
Inventors: |
Yatskov; Alexander I.;
(Kenmore, WA) |
Correspondence
Address: |
PERKINS COIE LLP;PATENT-SEA
P.O. BOX 1247
SEATTLE
WA
98111-1247
US
|
Family ID: |
40752923 |
Appl. No.: |
11/958114 |
Filed: |
December 17, 2007 |
Current U.S.
Class: |
361/679.49 ;
165/104.33 |
Current CPC
Class: |
F28D 2021/0064 20130101;
H05K 7/2039 20130101; H05K 7/20572 20130101; H05K 7/20736 20130101;
F28D 1/05383 20130101; F28F 1/12 20130101; G06F 1/20 20130101; H05K
7/20709 20130101; H05K 7/20218 20130101; F28D 1/0426 20130101; F28F
1/022 20130101; H05K 7/20009 20130101 |
Class at
Publication: |
361/679.49 ;
165/104.33 |
International
Class: |
H05K 7/20 20060101
H05K007/20; F28D 15/00 20060101 F28D015/00 |
Claims
1. A computer system, comprising: a computer cabinet having: an air
inlet; an air outlet spaced apart from the air inlet; and a
plurality of computer module compartments positioned between the
air inlet and the air outlet, wherein the air inlet, the air
outlet, and the computer module compartments define an air flow
path through the computer cabinet; and a heat exchanger positioned
between two adjacent computer module compartments, the heat
exchanger including a plurality of heat exchange elements canted
relative to the air flow path.
2. The computer system of claim 1 wherein the heat exchange
elements form an angle of from about 10.degree. to about 45.degree.
relative to the air flow path.
3. The computer system of claim I wherein individual heat exchange
elements include a plurality of fins between a first end and a
second end, and wherein at least one of the passage portions and
the plurality of fins are canted relative to the air flow path.
4. The computer system of claim 3 wherein the passage portion
includes a plurality of internal channels extending between the
first end and the second end.
5. The computer system of claim 1 wherein the heat exchange
elements include a first heat exchange element and a second heat
exchange element, and wherein the first heat exchange element forms
a first angle relative to the air flow path and the second heat
exchange element forms a second angle relative to the air flow
path, the first angle being different than the second angle.
6. A computer system, comprising: a computer cabinet having a
plurality of computer module compartments positioned between an air
inlet and an air outlet; a heat exchanger positioned between two
adjacent computer module compartments, the heat exchanger including
a plurality of heat exchange elements in fluid communication with
an inlet manifold and an outlet manifold, wherein the individual
heat exchange elements include a plurality of internal channels
configured to receive a working fluid from the inlet manifold and
transfer the working fluid to the outlet manifold, the individual
internal channels having different cross-sectional shapes.
7. The computer system of claim 6 wherein the internal channels
have different cross-sectional areas.
8. The computer system of claim 6 wherein the air inlet, the air
outlet, and the computer module compartments define an air flow
path through the computer cabinet, and wherein the internal
channels have cross-sectional areas that sequentially decrease
along the air flow path.
9. (canceled)
10. A computer system, comprising: a computer cabinet having a
plurality of computer module compartments positioned between an air
inlet and an air outlet: and a heat exchanger positioned between
two adjacent computer module compartments, the heat exchanger
including a plurality of heat exchange elements individually having
a passage portion and a plurality of fins extending from the
passage portion, wherein the plurality of fins include a first fin
portion having a first configuration and a second fin portion
having a second configuration different than the first
configuration, wherein the air inlet, the air outlet, and the
computer module compartments define an air flow path through the
computer cabinet, and wherein the first and second fin portions are
arranged at least partially along the air flow path.
11. The computer system of claim 10 wherein the first fin portion
is upstream of the second fin portion along the air flow path.
12. The computer system of claim 10 wherein the first fin portion
is upstream of the second fin portion along the air flow path, and
wherein the second fin portion has a larger number of fins than the
first fin portion.
13. The computer system of claim 10 wherein the first fin portion
is upstream of the second fin portion along the air flow path, and
wherein the second fin portion has a higher heat conductance than
the first fin portion.
14. A computer system, comprising: a computer cabinet having a
plurality of computer module compartments positioned between an air
inlet and an air outlet, wherein the air inlet, the air outlet, and
the computer module compartments define an air flow path through
the computer cabinet; and a heat exchanger positioned between two
adjacent computer module compartments, the heat exchanger including
a first flow path and a second flow path in fluid isolation from
the first flow path.
15. The computer system of claim 14 wherein the first and second
flow paths are arranged sequentially along the air flow path.
16. The computer system of claim 14 wherein the heat exchanger
includes an inlet manifold having an inlet divider separating the
inlet manifold into a first inlet volume and a second inlet volume;
an outlet manifold having an outlet divider separating the outlet
manifold into a first outlet volume and a second outlet volume; and
a plurality of heat exchange elements positioned between the inlet
manifold and the outlet manifold, the individual heat exchange
elements including a passage portion having a first channel portion
and a second channel portion, wherein the first channel portion is
in fluid communication with the first inlet volume and the first
outlet volume, and wherein the second channel portion is in fluid
communication with the second inlet volume and the second outlet
volume.
17. The computer system of claim 16 wherein the first inlet volume,
the first channel portion, and the first outlet volume at least
partially define the first flow path, and wherein the second inlet
volume, the second channel portion, and the second outlet volume at
least partially define the second flow path.
18. The computer system of claim 16, further comprising a first
working fluid portion in the first flow path and a second working
fluid portion in the second flow path, and wherein the first
working fluid portion and the second working fluid portion have
different physical characteristics.
19. The computer system of claim 18 wherein the first working fluid
portion has at least one of a higher flow rate, a higher heat
transfer coefficient, a lower boiling point, a higher heat of
vaporization than the second working fluid portion.
20. The computer system of claim 14 wherein the heat exchanger
includes a first manifold having a first divider separating the
first manifold into a first inlet volume and a first outlet volume;
a second manifold having a second divider separating the second
manifold into a second inlet volume and a second outlet volume; a
first heat exchange element in fluid communication with the first
inlet volume and the second outlet volume while being isolated from
the second inlet volume and the first outlet volume; and a second
heat exchange element in fluid communication with the second inlet
volume and the first outlet volume while being isolated from the
first inlet volume and the second outlet volume, wherein the first
inlet volume, the first heat exchange element, and the second
outlet volume at least partially define the first flow path and the
second inlet volume, the second heat exchange element, and the
first outlet volume at least partially define the second flow
path.
21. The computer system of claim 20, further comprising a first
working fluid portion in the first flow path and a second working
fluid portion in the second flow path, and wherein the first
working fluid portion and the second working fluid portion have
different flow directions when flowing through the first and second
heat exchange elements.
22. The computer system of claim 20, further comprising a first
working fluid portion in the first flow path and a second working
fluid portion in the second flow path, and wherein computer system
further includes a directing means for directing the first working
fluid portion to flow through the first heat exchange element in a
first direction and the second working fluid portion to flow
through the second heat exchange element in a second direction
opposite of the first direction.
23. A method for operating a computer cabinet having a plurality of
computer module compartments positioned between an air inlet and an
air outlet and a heat exchanger positioned between two adjacent
computer module compartments, the method comprising: flowing a
first working fluid portion along a first flow path of the heat
exchanger; flowing a second working fluid portion in a second flow
path of the heat exchanger, the first and second flow paths being
in fluid isolation from each other; and controlling at least one
characteristic of at least one of the first and second working
fluid portions.
24. The computer system of claim 23 wherein controlling at least
one characteristic includes controlling a flow rate, a heat
transfer coefficient, a boiling point, and/or a heat of
vaporization of the first and/or second working fluid portions.
25. The computer system of claim 23 wherein controlling at least
one characteristic includes flowing the first and second working
fluids in generally opposite directions across the heat exchanger.
Description
TECHNICAL FIELD
[0001] The present disclosure relates generally to cooling systems
and heat exchangers for cooling electronic components in computer
systems.
BACKGROUND
[0002] Supercomputers and other large computer systems typically
include a large number of computer modules housed in cabinets
arranged in banks. The computer modules are typically positioned in
close proximity to each other. During operation, the close
proximity can make dissipating heat generated by the modules
difficult. If not dissipated, the heat can damage the modules or
significantly reduce system performance.
[0003] One conventional technique for computer module cooling
includes drawing air into the cabinet to cool the computer modules
and discharging the heated air to the room. One shortcoming of this
technique, however, is that the heat capacity of the cooling air
can quickly become saturated. As a result, some of the computer
modules may not be adequately cooled. Accordingly, there is a need
to effectively dissipate heat generated by computer modules during
operation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1A is a partially schematic elevation view of a
computer system having internal heat exchangers configured in
accordance with an embodiment of the invention.
[0005] FIG. 1B is an enlarged perspective view of a heat exchanger
having canted heat exchange elements configured in accordance with
an embodiment of the invention.
[0006] FIG. 1C is an enlarged, cross-sectional side view of two
heat exchange elements from the heat exchanger of FIG. 1B,
configured in accordance with an embodiment of the invention.
[0007] FIG. 2 is a cross-sectional side view of a heat exchange
element having non-identical internal channels configured in
accordance with another embodiment of the invention.
[0008] FIG. 3 is a front view of a heat exchange element having a
plurality of fin configurations positioned along an air flow path
in accordance with another embodiment of the invention.
[0009] FIG. 4 is a perspective view of a heat exchanger having
partitioned inlet and/or outlet manifolds configured in accordance
with another embodiment of the invention and suitable for use in
the computer system of FIG. 1A.
[0010] FIG. 5 is a top view of a heat exchanger having
counter-flowing working fluids configured in accordance with a
further embodiment of the invention and suitable for use in the
computer system of FIG. 1A.
DETAILED DESCRIPTION
[0011] The following disclosure describes several embodiments of
cooling systems for use with supercomputers and/or other computer
systems. Persons of ordinary skill in the art will understand,
however, that the invention can have other embodiments with
additional features, or without several of the features shown and
described below with reference to FIGS. 1-5. In the Figures,
identical reference numbers identify structurally and/or
functionally identical, or at least generally similar,
elements.
[0012] FIG. 1A is a partially schematic elevation view of a
computer system 100 having a plurality of internal heat exchangers
118 (identified individually as heat exchangers 118a-d) configured
in accordance with an embodiment of the invention. The computer
system 100 can include a computer cabinet 102 in a room 101.
Working fluid lines 106 (identified individually as a supply line
106a and a return line 106b) connect the computer cabinet 102 to a
heat removal system 104. In the illustrated embodiment, the heat
removal system 104 is situated in the room 101 and spaced apart
from the computer cabinet 102. In other embodiments, however, the
heat removal system 104 can be integrated into the computer cabinet
102, positioned outside the room 101, or situated in other suitable
places.
[0013] The computer cabinet 102 can include an air inlet 114 for
receiving cooling air from the room 101 or a floor plenum (not
shown), an air outlet 116 for discharging air to the room 101, and
a plurality of computer module compartments 120 (identified
individually as first, second, and third computer module
compartments 120a-c, respectively) arranged vertically between the
air inlet 114 and the air outlet 116 in a chassis 110. Individual
computer module compartments 120 hold a plurality of computer
modules 112 oriented edgewise with respect to the flow of cooling
air through the chassis 110.
[0014] The computer cabinet 102 can also hold a plurality of heat
exchangers 118 in the chassis 110. As described in greater detail
below with reference to FIGS. 1B-4, the individual heat exchangers
118 can be configured to receive a working fluid (not shown) from
the heat removal system 104 via the supply line 106a. After flowing
through the heat exchangers 118, the working fluid returns to the
heat removal system 104 via the return line 106b. The working fluid
can include hydrofluorocarbons, hydrochlorofluorocarbons,
chlorofluorocarbons, ammonia, and/or other suitable refrigerants
known in the art. The working fluid can include a vapor phase
fluid, a liquid phase fluid, or a two-phase fluid when flowing
through the heat exchangers 118.
[0015] The computer cabinet 102 can additionally include an air
mover 130 (e.g., a fan) positioned proximate to the air inlet 114
to facilitate movement of the cooling air through the chassis 110
along a flow path 117. The air mover 130 can draw air from the room
101 or a floor plenum into the chassis 110 through the air inlet
114. The air then flows through the chassis 110 past the computer
modules 112, and exits the chassis 110 via the air outlet 116.
[0016] The heat removal system 104 can include a pump 124 in fluid
communication with a condenser 122. The condenser 122 can be a
shell-and-tube type heat exchanger, a plate-and-frame type heat
exchanger, or other suitable type of heat exchanger known in the
art. The condenser 122 can include a working fluid inlet 126a for
receiving heated working fluid returning from the computer cabinet
102, and a working fluid outlet 126b for supplying cooled working
fluid to the pump 124. The condenser 122 can also include a coolant
inlet 128a and a coolant outlet 128b for circulating chilled water,
cooling water, or other suitable coolant (not shown) to cool the
working fluid. The pump 124 can include a positive displacement
pump, a centrifugal pump, or other suitable type of pump for
circulating the working fluid back to the heat exchangers 118 via
the supply line 106a.
[0017] During operation of the computer system 100, the air mover
130 draws air into the chassis 110 through the air inlet 114. The
first heat exchanger 118a cools the air before it flows into the
first compartment 120a. As the air flows through the first
compartment 120a, the computer modules 112 in the first compartment
120a transfer heat to the air. The second heat exchanger 118b then
cools the air before the air passes into the second compartment
120b by absorbing heat from the air into the working fluid. The air
is similarly cooled by the third heat exchanger 118c before flowing
into the third compartment 120c. The fourth heat exchanger 118d
then cools the heated air leaving the third compartment 120c before
the air is discharged to the room 101 via the air outlet 116.
[0018] In one embodiment, the working fluid is in phase transition
between liquid and vapor as the working fluid leaves the heat
exchangers 118. In other embodiments, the working fluid can have
other phase conditions at this time. The heated working fluid from
the heat exchangers 118 returns to the condenser 122 via the return
line 106b. The coolant in the condenser 122 cools the working fluid
before the pump 124 circulates the working fluid back to the heat
exchangers 118.
[0019] Only a single computer cabinet 102 is shown in FIG. 1A for
purposes of illustration and ease of reference. In other
embodiments, however, supercomputers and other large computer
systems can include a plurality of computer cabinets arranged in
banks or other configurations. In such embodiments, the heat
removal system 104 can provide working fluid to one or more of the
computer cabinets 102 via an appropriately configured piping
circuit. Further, although the heat exchangers 118 have been
described above in the context of working fluid-type heat
exchangers, in other embodiments, other types of heat exchangers
can be used to inter-cool the air moving through the compartments
120 without departing from the spirit or scope of the present
invention.
[0020] FIG. 1B is an enlarged perspective view of one of the heat
exchangers 118 configured in accordance with an embodiment of the
invention. The heat exchanger 118 can include a plurality of heat
exchange elements 132 extending between and in fluid communication
with an inlet manifold 134 and an outlet manifold 135. Although
four heat exchange elements 132 are shown in FIG. 1B, in other
embodiments, the heat exchanger 118 can include more or fewer heat
exchange elements 132 depending on a number of factors including
heat load, cost, manufacturability, etc.
[0021] The inlet manifold 134 can include a distribution section
137c extending between an inlet port 137a and a capped inlet end
137b. In the illustrated embodiment, the distribution section 137c
includes a generally tubular structure (e.g., a section of a pipe
or a tube) with a plurality of first slots 137d arranged along a
length of the distribution section 137c. The first slots 137d are
configured to receive first end portions of the heat exchange
elements 132. In other embodiments, the distribution section 137c
can have other configurations to accommodate other factors.
[0022] In the illustrated embodiment, the outlet manifold 135 is
generally similar to the inlet manifold 134. For example, the
outlet manifold 135 includes a collection section 139c extending
between an outlet port 139a and a capped outlet end 139b. The
collection section 139c includes a generally tubular structure with
a plurality of second slots 139d arranged along a length of the
collection section 139c in one-to-one correspondence with the first
slots 137d. In other embodiments, the outlet manifold 135 can have
other configurations, including others that differ from the inlet
manifold 134. For example, the collection section 139c can have a
different cross-sectional shape and/or a different size than the
distribution section 137c.
[0023] The individual heat exchange elements 132 can include a
plurality of fins 142 extending from a passage portion 140. A first
end portion 132a of the passage portion 140 is coupled to the inlet
manifold 134 via the first slots 137d, and a second end portion
132b of the passage portion 140 is coupled to the outlet manifold
135 via the second slots 139d. In the illustrated embodiment, the
passage portion 140 extends into both the inlet manifold 134 and
the outlet manifold 135. In other embodiments, however, the ends of
the passage portion 140 can be generally flush with the first
and/or second slots 137d, 139d. Further details of several
embodiments of the passage portion 140 are described below with
reference to FIG. 1C.
[0024] FIG. 1C is an enlarged side view of two of the heat exchange
elements 132 of FIG. 1B, configured in accordance with one
embodiment of the invention. As illustrated in FIG. 1C, the heat
exchange elements 132 can be at least generally parallel to each
other with a gap D (e.g., from about 1 to about 2 cm, or any other
desired spacing) therebetween. In other embodiments, however, at
least some of the heat exchange elements 132 can be nonparallel to
the other heat exchange elements 132. The gap D can form an air
passage 136 in fluid communication with the air flow path 117. The
air passage 136 allows cooling air to flow past the heat exchange
elements 132 during operation of the computer system 100.
[0025] In certain embodiments, individual heat exchange elements
132 can be canted relative to the incoming air flow path 117a. For
example, as illustrated in FIG. 1C, the heat exchange elements 132
can form an angle A of from about 10.degree. to about 45.degree.,
preferably from about 15.degree. to about 40.degree., and more
preferably about 20.degree. to about 30.degree. relative to the air
flow path 117a. In other embodiments, the heat exchange elements
132 and the air flow path 117a can form other suitable angles. Each
of the heat exchange elements 132 can form the same angle or
different angles relative to the air flow path 117. For example,
the angles can increase or decrease (e.g., linearly, exponentially,
etc.) from one heat exchange element 132 to another.
[0026] The individual heat exchange elements 132 can include a
plurality of internal fluid channels 144 (identified individually
as first, second, third, and fourth internal channels 144a-d,
respectively). In the illustrated embodiment, the internal channels
144 have generally the same cross-sectional shape, e.g., a
generally rectangular shape, and generally the same cross-sectional
area. In other embodiments, however, the internal channels 144 can
have other cross-sectional shapes, such as triangular shapes,
circular shapes, oval shapes, and/or other suitable shapes and/or
cross-sectional areas. In further embodiments, the internal
channels 144 can have non-identical configurations, as described in
more detail below with reference to FIG. 2.
[0027] Referring to FIG. 1B and FIG. 1C together, in operation, a
working fluid (not shown) flows into the inlet manifold 134 via the
inlet port 137a, as indicated by the arrow 131a. The inlet manifold
134 distributes the working fluid to the internal channels 144 at
the first end 132a of each of the heat exchange elements 132. The
working fluid flows across the heat exchange elements 132 from the
first end 132a toward the second end 132b. As the working fluid
flows across the heat exchange elements 132, the working fluid
absorbs heat from cooling air flowing through the air passage 136
and/or past the fins 142. As a result, in one embodiment, the
working fluid can be at least partially vaporized (i.e., a
two-phase fluid) at the outlet manifold 135. In other embodiments,
the working fluid can be sub-cooled at the outlet manifold 135. In
further embodiments, the working fluid can be substantially
completely vaporized at the outlet manifold 135. In all these
embodiments, the collection section 139c of the outlet manifold 135
collects the heated working fluid and returns the heated working
fluid to the heat removal system 104 (FIG. 1A) via the outlet port
139a, as indicated by the arrow 131b.
[0028] Canting the heat exchange elements 132 can improve heat
distribution along a length L (FIG. 1C) of the heat exchange
elements 132. For example, as the cooling air flows past the heat
exchange elements 132, the working fluid in one of the internal
channels 144 (e.g., the fourth internal channel 144d) can absorb
heat from air streams that have not been significantly cooled by
working fluid flowing through other internal channels 144 (e.g.,
the first, second, and/or third internal channels 144a-c). As a
result, heat distribution along the length L of the heat exchange
element 132 can be more efficient than with heat exchange elements
arranged parallel to the air flow. The canted heat exchange
elements 132 can also increase the heat transfer area without
significantly affecting the height of the heat exchanger 118.
Furthermore, the canted heat exchange elements 132 can improve
energy distribution in the computer cabinet 102 (FIG. 1A) because
the canted heat exchange elements 132 can deflect cooling air to
other parts of the computer cabinet 102 during operation, as
indicated by the arrow 117.
[0029] FIG. 2 is a cross-sectional side view of a heat exchange
element 232 having non-identical internal channels configured in
accordance with another embodiment of the invention. As illustrated
in FIG. 2, the heat exchange element 232 can include a plurality of
internal channels 244 (identified individually as first, second,
third, and fourth internal channel 244a-d, respectively), and at
least one internal channel 244 has a different internal
configuration than others. For example, the cross-sectional area of
the internal channels 244 can sequentially decrease from the first
internal channel 244a to the fourth internal channel 244d. In other
embodiments, the first and second internal channels 244a-b can have
a first cross-sectional area, and the third and fourth internal
channels 244c-d can have a second cross-sectional area, smaller
than the first cross-sectional area. As the foregoing illustrates,
in further embodiments, the internal channels 244 can have
different cross-sectional shapes and/or other arrangements.
[0030] In operation, the different internal configurations of the
internal channels 244 can allow the working fluid to have different
mass flow rates when flowing through the internal channels 244. For
example, in the illustrated embodiment, the first internal channel
244a has a larger cross-sectional area than that of the second
internal channel 244b. As a result, the mass flow rate of working
fluid through the first internal channel 244a will be greater than
the mass flow rate of the working fluid through the second internal
channel 244b for a given fluid pressure.
[0031] Controlling the flow rate of the working fluid flowing
through individual internal channels 244 can improve heat transfer
performance of the heat exchange element 232. The inventor has
recognized that, in certain situations, the working fluid flowing
through the first internal channel 244a can be completely vaporized
before and/or when it reaches the outlet manifold 135 (FIG. 1B).
The completely vaporized working fluid typically cannot efficiently
transfer heat because of a low heat capacity. By increasing the
flow rate of the working fluid flowing through the first internal
channel 244a, the working fluid can be at least a two-phase fluid
when it reaches the outlet manifold 135, thus improving the heat
transfer efficiency.
[0032] In other embodiments, the heat exchange element 232 can
include other features that affect the mass flow rate of the
working fluid in the internal channels 244. For example, individual
internal channels 244 can include an orifice, a nozzle, and/or
other flow restricting components. In another example, the heat
exchange element 232 can include a barrier (not shown) that
partially blocks the cross-section of at least one of the internal
channels 244.
[0033] FIG. 3 is a front view of a heat exchange element 332 having
a fin configuration configured in accordance with a further
embodiment of the invention. In this embodiment, the heat exchange
element 332 includes a first fin portion 342a and a second fin
portion 342b arranged along the air flow path 117. The first fin
portion 342a can include a plurality of first fins 343a, and the
second fin portion 342b can include a plurality of second fins
343b, different than the first fins 343a. For example, in the
illustrated embodiment, the second fin portion 342b can have a
larger number of fins 343b than the first fin portion 342a. In
another embodiment, the second fin portion 342b can include
different types of fins than the first fin portion 342a (e.g., the
second fins 343b can have different heights, thicknesses, etc). In
a further embodiment, the second fins 343b can have a higher heat
conductance than the first fins 343a. In any of these embodiments,
the second fin portion 342b can have a higher heat transfer
coefficient that the first fin portion 342a.
[0034] Having different fin configurations along the air flow path
117 can improve the heat transfer efficiency between the working
fluid and the cooling air. The inventor has recognized that if the
fins have the same configuration along the length L of the heat
exchange element 332, the working fluid flowing through the fourth
internal channel 144d (FIG. 1C) is likely to be mostly liquid when
it reaches the outlet manifold 135 (FIG. 1B). Thus, the heat
transfer between the working fluid and the cooling air is limited
because the mostly liquid working fluid typically has a latent heat
capacity much lower than its heat of vaporization. The inventor has
further recognized that the limiting factor in the heat transfer
between the working fluid and the cooling air is the heat transfer
rate between the fins and the cooling air. Thus, by increasing the
heat transfer efficiency and/or capability of the second fin
portion 342b, the heat transfer between the working fluid in the
fourth internal channel 144d and the cooling air can be
improved.
[0035] FIG. 4 is a partially exploded perspective view of a heat
exchanger 418 configured in accordance with another embodiment of
the invention and suitable for use in the computer system 100 of
FIG. 1A. Many features of the heat exchanger 418 can be at least
generally similar in structure and function to the heat exchangers
118 describe above. For example, the heat exchanger 418 can include
a plurality of heat exchange elements 432 extending between an
inlet manifold 434 and an outlet manifold 435. The individual heat
exchange elements 432 can include a plurality of fins 442 extending
from a passage portion 440. The passage portion 440 can be
generally similar to the passage portion 140 of FIGS. 1B and 1C, or
the passage portion 240 of FIG. 2.
[0036] The inlet manifold 434 can include a distribution section
437c extending between an inlet opening 437a and a capped inlet end
437b. The inlet manifold 434 can also include an inlet divider 448
extending between the inlet opening 437a and the inlet end 437b.
The inlet divider 448 separates the distribution section 437c into
a first inlet volume 450a and a second inlet volume 450b. The inlet
divider 448 also separates the inlet opening 437a into a first
inlet port 452a and a second inlet port 452b.
[0037] In the illustrated embodiment, the outlet manifold 435 is
generally similar to the inlet manifold 434. For example, the
outlet manifold 435 includes a collection section 439c extending
between an outlet opening 439a and a capped outlet end 439b. The
outlet manifold 435 can also include an outlet divider 458 that
separates the collection section 439c into a first outlet volume
460a and a second outlet volume 460b. The outlet divider 458 also
separates the outlet opening 439a into a first outlet port 462a and
a second outlet port 462b.
[0038] The inlet and outlet dividers 448, 458 cooperate to separate
the internal channels 144 (FIG. 1C) of individual heat exchange
elements 432 into a first channel portion 444a corresponding to the
first inlet/outlet volumes 450a, 460a and a second channel portion
444b corresponding to the second inlet/outlet volumes 450b, 460b.
Thus, the first inlet volume 450a, the first channel portion 444a,
and the first outlet volume 460a form a first flow path of the heat
exchanger 418. Similarly, the second inlet volume 450b, the second
channel portion 444b, and the second outlet volume 460b form a
second flow path of the heat exchanger 418. The first and second
flow paths are isolated from each other and arranged along the air
flow path 117.
[0039] In operation, the heat exchanger 418 can receive a first
working fluid portion via the first inlet port 452a, as indicated
by arrow 470a, and a second working fluid portion via the second
inlet port 452b, as indicated by arrow 472a. The first and second
inlet volumes 450a-b distribute the first and second working fluid
portions to the first and second channel portions 444a-b,
respectively. The first and second working fluid portions flow
across the heat exchange elements 432, as indicated by arrows 470b
and 472b, respectively. As the first and second working fluid
portions flow across the heat exchange elements 432, they absorb
heat from the cooling air flowing past the fins 442. The first and
second outlet volumes 460a-b collect the heated first and second
working fluid portions and returns them to the heat removal system
104 (FIG. 1A) via the first and second outlet ports 462a and 462b,
respectively, as indicated by arrows 470c and 472c,
respectively.
[0040] The first and second working fluid portions can have
different physical characteristics. For example, in one embodiment,
the first working fluid portion can have a mass flow rate that is
less than the second working fluid portion. In another embodiment,
the first working fluid portion can have a higher heat transfer
coefficient than the second working fluid portion. In a further
embodiment, the first working fluid portion can have a lower
boiling point than the second working fluid portion. In yet another
embodiment, the first working fluid portion can have a higher heat
of vaporization than the second working fluid portion.
[0041] By controlling the physical characteristics of the first and
second working fluid portions, the heat exchanger 418 can have
improved heat transfer performance compared to conventional heat
exchangers. The inventor has recognized that if the same working
fluid is flowing through all the internal channels of the heat
exchange elements 432, the working fluid in those channels
proximate to the incoming cooling air is likely to be completely
vaporized, while the working fluid in other channels spaced apart
from the incoming cooling air may still be in liquid phase. Thus,
by selecting appropriate heat transfer characteristics of the first
and second working fluids, an operator can improve the heat
transfer between the working fluid and the cooling air.
[0042] Although the inlet divider 448 and the outlet divider 458
are illustrated in FIG. 4 as being generally perpendicular to the
air flow path 117, in other embodiments, at least one of the inlet
divider 448 and the outlet divider 458 can be canted relative to
the air flow path 117. In further embodiments, at least one of the
inlet divider 448 and the outlet divider 458 can be omitted, and/or
at least one of the first and second inlet/outlet volumes 450a-b,
460a-b can be standalone structures. For example, the first and
second inlet volumes 450a-b can each include a generally tubular
structure and spaced apart from each other.
[0043] FIG. 5 is a top view of a heat exchanger 518 configured in
accordance with a further embodiment of the invention and suitable
for use in the computer system 100 of FIG. 1A. Many features of the
heat exchanger 518 can be at least generally similar in structure
and function to the heat exchangers 118 describe above. For
example, the heat exchanger 518 can include a plurality of heat
exchange elements 532 (identified individually as first, second,
third, and fourth heat exchange elements 532a-d, respectively)
extending between a first manifold 534 and a second manifold 535.
The individual heat exchange elements 532 can include a passage
portion 540 and have a plurality of fins 542 extending from the
passage portion 540. The passage portion 540 can be generally
similar to the passage portion 140 of FIGS. 1B and 1C, or FIG.
2.
[0044] The first manifold 534 can include a first intermediate
section 537c extending between a first opening 537a and a capped
first end 537b. The first manifold 534 can also include a first
divider 548 extending between the first opening 537a and the first
end 537b. The first divider 548 separates the first intermediate
section 537c into a first distribution volume 550a and a first
collection volume 550b. The first divider 548 also separates the
first opening 537a into a first inlet port 552a and a first outlet
port 552b.
[0045] The first distribution volume 550a and the first collection
volume 550b are in fluid communication with only a portion of the
heat exchange elements 532. For example, in the illustrated
embodiment, the first distribution volume 550a is in fluid
communication with the second and fourth heat exchange elements
532b, 532d, and the first collection volume 550b is in fluid
communication with the first and third heat exchange elements 532a,
532c. In other embodiments, the first manifold 534 can also have
other flow configurations.
[0046] The second manifold 535 can include a second intermediate
section 539c extending between a second opening 539a and a capped
second end 539b. The second manifold 535 can also include a second
divider 558 extending between the second opening 539a and the
second end 539b. The second divider 558 separates the second
intermediate section 539c into a second distribution volume 560a
and a second collection volume 560b. The second divider 558 also
separates the second opening 539a into a second inlet port 562a and
a second outlet port 562b.
[0047] The second distribution volume 560a and the second
collection volume 560b are in fluid communication with only a
portion of the heat exchange elements 532. For example, in the
illustrated embodiment, the second distribution volume 560a is in
fluid communication with the first and third heat exchange elements
532a, 532c, and the second collection volume 560b is in fluid
communication with the second and fourth heat exchange elements
532b, 532d. In other embodiments, the second manifold 535 can also
have other flow configurations.
[0048] The heat exchanger 518 can thus have a first flow path from
the first inlet port 552a to the second outlet port 562b via the
first distribution volume 550a, the second and fourth heat exchange
elements 532b, 532d, and the second collection volume 560b. The
heat exchanger 518 can also have a second flow path from the second
inlet port 562a to the first outlet port 552b via the second
distribution volume 560a, the first and third heat exchange
elements 532a, 532c, and the first collection volume 550b.
[0049] In operation, the heat exchanger 518 can receive a first
working fluid portion via the first inlet port 552a, as indicated
by arrow 570a, and a second working fluid portion via the second
inlet port 562a, as indicated by arrow 572a. The first and second
distribution volumes 550a, 560a distribute the first and second
working fluid portions to corresponding heat exchange elements 532.
The first working fluid portion then flows across the second and
fourth heat exchange elements 532b, 532d in a first direction, as
indicated by arrow 570b. The second working fluid portion then
flows across the first and third heat exchange elements 532a, 532c
in a second direction, as indicated by arrow 572b. In the
illustrated embodiment, the second direction is generally opposite
the first direction. In other embodiments, the first and second
directions can form an angle of about 120.degree. to about
180.degree.. As the first and second working fluid portions flow
across the heat exchange elements 532, the cooling air flowing past
the fins 542 heats the first and second working fluid portions. The
first and second collection volumes 550b, 560b collect the heated
first and second working fluid portions and return them to the heat
removal system 104 (FIG. 1A) via the first and second outlet ports
552b, 562b, as indicated by arrows 570c, 572c, respectively.
[0050] By flowing the first and second working fluid portions in
generally opposite directions, the heat exchanger 518 can have
improved heat transfer efficiency compared to conventional heat
exchangers. The inventor has recognized that the heat transfer
efficiency decreases as the first and/or second portions of working
fluid flow across the heat exchange elements. Thus, if the first
and second working fluid portions flow in the same direction, one
side of the heat exchanger 518 may have insufficient heat transfer.
However, by alternating the flow directions of the first and second
working fluid portions, the heat transfer efficiency between the
first and second working fluid portions and the cooling air can be
improved.
[0051] From the foregoing, it will be appreciated that specific
embodiments of the invention have been described herein for
purposes of illustration, but that various modifications may be
made without deviating from the spirit and scope of the invention.
For example, the heat exchangers shown in FIGS. 4 and 5 can also
incorporate the heat exchange elements shown in FIGS. 2 and 3. In
another example, the heat exchanger shown in FIG. 1B can also
incorporate the inlet/outlet manifolds of FIG. 4 or FIG. 5.
Further, while advantages associated with certain embodiments of
the invention have been described in the context of those
embodiments, other embodiments may also exhibit such advantages,
and not all embodiments need necessarily exhibit such advantages to
fall within the scope of the invention. Accordingly, the invention
is not limited, except as by the appended claims.
* * * * *