U.S. patent application number 12/265726 was filed with the patent office on 2010-08-26 for phase-separated evaporator, blade-thru condenser and heat dissipation system thereof.
This patent application is currently assigned to ArticChoke Enterprises. Invention is credited to Frederick K. Husher, Jee Shum, Paul Silverstein.
Application Number | 20100214740 12/265726 |
Document ID | / |
Family ID | 46206146 |
Filed Date | 2010-08-26 |
United States Patent
Application |
20100214740 |
Kind Code |
A1 |
Silverstein; Paul ; et
al. |
August 26, 2010 |
Phase-Separated Evaporator, Blade-Thru Condenser and Heat
Dissipation System Thereof
Abstract
A phase-separated evaporator includes a boiler plate and a phase
separation chamber that includes a housing, connected to the boiler
plate, having a gas port and a liquid port; and a phase partitioner
connected to interiors of the housing, dividing the phase-separated
evaporator into a vapor directing compartment and a condensate
directing compartment. The phase partitioner includes a partition
panel and multiple feeding injectors extending from the partition
panel, with the injector tips disposed immediately above the boiler
plate. The returning condensate from a condenser enters from the
liquid port into the condensate directing compartment and feeds
onto the boiler plate through the feeding injectors; while the
vapor generated in the vapor directing compartment exits from the
gas port, without encountering the condensate. Further disclosed
are a high efficiency heat dissipation system utilizing the
phase-separated evaporator and a blade-thru condenser, and a
computer system utilizing the heat dissipation system.
Inventors: |
Silverstein; Paul; (Miami,
FL) ; Husher; Frederick K.; (Pembroke Pines, FL)
; Shum; Jee; (Miramar, FL) |
Correspondence
Address: |
YI LI
CUSPA TECHNOLOGY LAW ASSOCIATES, 11820 SW 107 AVENUE
MIAMI
FL
33176
US
|
Assignee: |
ArticChoke Enterprises
Miami
FL
|
Family ID: |
46206146 |
Appl. No.: |
12/265726 |
Filed: |
November 5, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11800248 |
May 5, 2007 |
7450386 |
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12265726 |
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11494238 |
Jul 27, 2006 |
7686071 |
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11800248 |
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60797848 |
May 6, 2006 |
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60703945 |
Jul 30, 2005 |
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60797848 |
May 6, 2006 |
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Current U.S.
Class: |
361/679.52 ;
165/185; 62/519 |
Current CPC
Class: |
H01L 2924/0002 20130101;
F25B 23/006 20130101; F25B 39/00 20130101; H01L 23/427 20130101;
H01L 2924/00 20130101; F28D 15/0266 20130101; H01L 2924/0002
20130101 |
Class at
Publication: |
361/679.52 ;
62/519; 165/185 |
International
Class: |
G06F 1/20 20060101
G06F001/20; F25B 39/02 20060101 F25B039/02; F28F 7/00 20060101
F28F007/00 |
Claims
1. A phase-separated evaporator comprising: (a) a boiler plate; and
(b) a phase separation chamber comprising: (i) a housing having a
base connected to said boiler plate; said housing having a liquid
port and a gas port; and (ii) a phase partitioner inside said
housing, dividing said phase-separated evaporator into a vapor
directing compartment on a side of said boiler plate and a
condensate directing compartment on an opposing side of said phase
partitioner; said vapor directing compartment being in
communication with said gas port and said condensate directing
compartment being in communication with said liquid port; said
phase partitioner including a plurality of openings permitting a
condensate in said condensate directing compartment to pass
therethrough to said vapor directing compartment.
2. The phase-separated evaporator of claim 1, wherein said phase
partitioner includes a partition panel and said openings include a
plurality of feeding injectors extending from a surface of said
partition panel within said vapor directing compartment toward an
upper surface of said boiler plate.
3. The phase-separated evaporator of claim 2, wherein each of said
feeding injectors has an injector inlet and an opposing injector
tip; and said injector tip is disposed immediately adjacent said
upper surface of said boiler plate.
4. The phase-separated evaporator of claim 2, wherein said
partition panel has a pressure vent opening for balancing pressure
between said condensate directing compartment and said vapor
directing compartment.
5. The phase-separated evaporator of claim 2, wherein said liquid
port and said gas port are positioned on a side wall of said
housing; and said liquid port is disposed between a top wall of
said housing and said partition panel, and said gas port is
disposed between said partition panel and said boiler plate.
6. The phase-separated evaporator of claim 1, wherein a top wall of
said housing and said partition panel incline along a longitudinal
axis of said phase separation chamber toward said boiler plate; and
said partition panel is substantially in parallel with said top
wall.
7. The phase-separated evaporator of claim 3, wherein said upper
surface of said boiler plate is coated with a micro porous coating
material.
8. The phase-separated evaporator of claim 7, wherein said upper
surface of said boiler plate comprises a plurality of pins
extending upward therefrom.
9. The phase-separated evaporator of claim 7, wherein said boiler
plate comprises a plurality of landing zones on said upper surface
in spaces among said pins, surfaces of said landing zones being
substantially free of said micro porous coating material; and said
injector tips are disposed immediately adjacent said landing
zones.
10. The phase-separated evaporator of claim 1, wherein said phase
partitioner and said housing are made of a thermal-insulating
material.
11. The phase-separated evaporator of claim 1, wherein a top wall
of said housing has an inclined section covering substantially an
upper surface of said boiler plate along a longitudinal axis of
said phase separation chamber, and a port section adjacent to, and
vertically extending above, said inclined section; and said liquid
port and said gas port are positioned on top of said port
section.
12. The phase-separated evaporator of claim 11, wherein said
partition panel includes an inclined panel substantially in
parallel with said inclined section of said top wall of said
housing and a vertical section extending from one end of said
inclined panel upwardly within said port section; and said inclined
panel comprises a plurality of feeding injectors extending
therefrom toward said boiler plate.
13. A heat dissipation system comprising: (a) a phase-separated
evaporator, comprising: (i) a boiler plate; and (ii) a phase
partitioner inside said housing, dividing said phase-separated
evaporator into a vapor directing compartment on a side of said
boiler plate and a condensate directing compartment on an opposing
side of said phase partitioner; said vapor directing compartment
being in communication with said gas port and said condensate
directing compartment being in communication with said liquid port;
said phase partitioner including a plurality of openings permitting
a condensate in said condensate directing compartment to pass
therethrough to said vapor directing compartment; (b) a condenser;
(c) a vapor conduit connected between said gas port of said
evaporator and an input interface of said condenser; and (d) a
condensate conduit connected between an output interface of said
condenser and said liquid port of said evaporator.
14. The heat dissipation system of claim 13 further comprising a
fan positioned adjacent to said condenser, for removing hot air
released from said condenser.
15. The heat dissipation system of claim 13, wherein said condenser
is a blade-thru condenser comprising: (a) a condenser core
comprising multiple substantially planar blades, each of said
multiple blades having at least one chamber formed monolithically
therein, a floor of said chamber having at least one aperture; said
multiple blades joined in parallel alignment, with said apertures
positioned to permit vapor and condensate to pass through said
apertures; (b) an input interface; and (c) an output interface.
16. The heat dissipation system of claim 15, wherein said apertures
include at least one reed.
17. The heat dissipation system of claim 13, wherein said condenser
is a blade-thru condenser comprising: (a) a condenser core
comprising multiple substantially planar blades joined in parallel
by one or more spacer rings disposed between two adjacent blades;
each of said blades comprising one or more chambers formed within
interiors of said spacer rings, wherein an area of said blades
enclosed within said spacer ring forms a floor of said chamber and
said spacer ring forms a wall of said chamber, said floor having at
least one aperture; said chambers of said multiple blades in
alignment to permit vapor and condensate to pass through said
apertures; (b) an input interface; and (c) an output interface.
18. The heat dissipation system of claim 17, wherein said floor of
said chamber and rest of said blades are monolithic.
19. A computer system comprising a heat dissipation system
comprising a phase-separated evaporator, a condenser, and a coolant
hermetically sealed therein; said phase-separated evaporator
comprising: (a) a boiler plate being in a direct contact with a
heat generating component of said computer system; and (b) a phase
separation chamber comprising a housing and a phase partitioner;
said housing having a base connected to said boiler plate and
having a liquid port and a gas port; and said phase partitioner
inside said housing, dividing said phase-separated evaporator into
a vapor directing compartment on a side of said boiler plate and a
condensate directing compartment on an opposing side of said phase
partitioner; said vapor directing compartment being in
communication with said gas port and said condensate directing
compartment being in communication with said liquid port; said
phase partitioner including a plurality of openings permitting a
condensate in said condensate directing compartment to pass
therethrough to said vapor directing compartment.
20. The computer system of claim 19, wherein said condenser
comprises a condenser core comprising multiple substantially planar
blades, each of said multiple blades having at least one chamber
formed monolithically therein, a floor of said chamber having at
least one aperture; said multiple blades jointed in parallel
alignment, with said apertures positioned to permit vapor and
condensate to pass through said apertures.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 11/800,248, filed on May 5, 2007, which claims
the benefit under 35 USC 119(e) of the provisional patent
application Ser. No. 60/797,848, filed May 6, 2006, and is a
continuation-in-part of U.S. patent application Ser. No.
11/494,238, filed on Jul. 27, 2006, which claims the benefit under
35 USC 119(e) of provisional patent application Ser. No.
60/703,945, filed Jul. 30, 2005, and provisional patent application
Ser. No. 60/797,848, filed May 6, 2006. All parent patent
applications are herein incorporated by reference in their
entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to an evaporator and a heat
dissipation system utilizing the evaporator. More specifically, the
evaporator includes phase-partitioner which separates the vapor and
the condensate into two compartments. The present invention further
relates to a high efficiency heat dissipation system utilizing the
phase-separated evaporator and a blade-thru condenser.
BACKGROUND OF THE INVENTION
[0003] With the never-ending increase of computing power,
effectively cooling a CPU has become a technical challenge. The
present temperature limit for a CPU is approximately 60.degree. C.
As the power of a CPU increases, more heat is generated; therefore,
the CPU requires a higher efficiency and capacity of the heat
dissipation device in order to provide an effective thermal
management to the computer system. Heat dissipation can be achieved
by moving the heat generated primarily at the CPU and other
components such as the memory controller, memory chips, graphics
processor or power chips, to a location where it can be safely
discharged to the ambient air.
[0004] One type conventional heat dissipation device is passive
metal heat sinks. The heat sinks are typically made of thermally
conductive metal blocks that can be attached to the cover plate of
a CPU for dissipating heat. The block can be fabricated to include
plurality of thin fins to increase the surface area for heat
dissipation. The heat sinks are only effective to dissipate heat
generated up to about 90 watts. Another type of conventional heat
dissipation device is heat pipes, which are only effective to
dissipate heat generated up to about 130 watts. Therefore, the
conventional heat dissipation devices have very limited capacities
and are inadequate for cooling the high power CPU, which operates
with a power of about 235 watts or higher.
[0005] At this time the computer industry in general believes that
liquid cooling is the only viable solution for the immediate
future. Recently, major computer manufacturers have started to
release high power computers using liquid cooling devices for
thermal management. For example, Dell's new top line system XPC 700
includes a refrigerated liquid cooling system. IBM has released its
Power 6 Plus chip at 5.2 GHz, which operates with a power in a
range of 300 to 425 watts and is expected to be supported with
liquid cooling devices. However, liquid cooling devices are
expensive, noisy and difficult to maintain.
[0006] In heat dissipation devices based on the phase exchange of a
coolant between the liquid and gas phases, the efficiency of the
heat dissipation devices depends on both the evaporator and the
condenser. Traditional evaporators only have one chamber or
compartment above the boiler plate. When the generated vapor exits
the evaporator, it encounters the returning condensate, this causes
a premature condensation of the vapor before it exits from the
evaporator. On the other hand, prior to the condensate reaches the
boiler plate, the condensate is already heated up by the vapor. As
such, the efficiency of the evaporator is compromised.
[0007] Based on the above, it is apparent that a strong need exists
in the computer industry for improved heat dissipation devices that
have higher efficiency and capacity for thermal management of
computer systems. Furthermore, there is also a strong need for
improved heat dissipation devices in other industries, such as
automobile and air conditioning.
SUMMARY OF THE INVENTION
[0008] In one aspect, the present invention is directed to a
phase-separated evaporator. In one embodiment, the phase-separated
evaporator comprises a boiler plate and a phase separation chamber
that comprises a housing having a base connected to the boiler
plate; the housing having a liquid port and a gas port; and a phase
partitioner connected to interiors of the housing, dividing the
phase-separated evaporator into a condensate directing compartment
and a vapor directing compartment. The condensate directing
compartment is in communication with the liquid port, and the vapor
directing compartment is in communication with the gas port. The
phase partitioner includes a partition panel and a plurality of
feeding injectors extending from the partition panel toward the
boiler plate.
[0009] In a further aspect, the present invention is directed to a
heat dissipation system utilizing the instant phase-separated
evaporator. The heat dissipation system comprises a phase-separated
evaporator as described above, a condenser, a vapor conduit
connected between the gas port of the evaporator and an input
interface of the condenser, and a condensate conduit connected
between an output interface of the condenser and the liquid port of
the evaporator. The heat dissipation system further comprises a fan
positioned adjacent to the condenser, for removing hot air released
from the condenser.
[0010] In one embodiment, the condenser is a blade-thru condenser.
In a specific embodiment, the blade-thru condenser comprises a
condenser core, an input interface, and an output interface. The
condenser core comprises multiple substantially planar blades, each
of the multiple blades having at least one chamber formed
monolithically therein, and a floor of the chamber having at least
one aperture. The multiple blades are joined in parallel alignment,
with the apertures positioned to permit vapor and condensate to
pass through the apertures. The apertures include at least one
reed.
[0011] In a further embodiment, the blade-thru condenser comprises
a condenser core that comprises multiple substantially planar
blades joined in parallel by one or more spacer rings disposed
between two adjacent blades. Each of the blades comprises one or
more chambers formed within interiors of the spacer rings, and a
floor of the chamber has at least one aperture. The chambers of the
multiple blades are in alignment to permit vapor and condensate to
pass through the apertures.
[0012] In another aspect, the present invention is directed to a
computer system that comprises a housing, a motherboard comprising
a central processing unit (CPU) and input, output interfaces, a fan
disposed within the housing, and a heat dissipation system
comprising the instant phase-separated evaporator with the boiler
plate in a direct contact with a heat generating component of the
computer and the condenser as described above. The heat generating
component includes the CPU, memory controller, memory chip,
graphics processor, or power chip.
[0013] The advantages of the present invention will become apparent
from the following description taken in conjunction with the
accompanying drawings showing the exemplary embodiments of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a perspective exterior view of the phase-separated
evaporator of one embodiment of the present invention.
[0015] FIG. 2 is a top view of the phase-separated evaporator shown
in FIG. 1.
[0016] FIG. 3 is a cross-sectional view of the phase-separated
evaporator of FIG. 1, along line A-A of FIG. 2.
[0017] FIG. 4 is a perspective cut-out view of the phase-separated
evaporator of FIG. 1, along line A-A of FIG. 2.
[0018] FIG. 5 is a see-through image view of the phase-separated
evaporator shown in FIGS. 1 and 4.
[0019] FIGS. 6 and 6A are top and side views of the phase
partitioner of the phase-separated evaporator shown in FIG. 3.
[0020] FIG. 6B is a cut-out view of the phase partitioner along
line A-A of FIG. 6.
[0021] FIG. 7 is a bottom perspective view of the phase partitioner
of the phase-separated evaporator shown in FIG. 3.
[0022] FIG. 8 is a top view of the boiler plate of the
phase-separated evaporator shown in FIG. 3, showing the locations
of the landing zones.
[0023] FIG. 9 is a perspective view of a heat dissipation system of
one embodiment of the present invention.
[0024] FIG. 10 is a cross-sectional view showing the
phase-separated evaporator of FIG. 3 positioned with a 90 degree
rotation.
[0025] FIG. 11 is a cross-sectional view of the phase-separated
evaporator of a further embodiment of the present invention.
[0026] FIG. 12 is a top view of the condenser core of the
blade-thru condenser of one embodiment of the present
invention.
[0027] FIG. 13 is a partial enlarged side view of the condenser
core along line A-A of FIG. 12.
[0028] FIG. 13A is a magnified side view of a solder joint between
two blades of the condenser core shown in FIG. 13.
[0029] FIG. 13B is magnified cross-sectional view of a reed of the
condenser core shown in FIG. 13.
[0030] FIG. 14 is a top view of the input manifold of the
blade-thru condenser of FIG. 9.
[0031] FIG. 14A is a cross-sectional view of the input manifold of
the blade-thru condenser along line C-C of FIG. 9.
[0032] FIG. 14B is a cross-sectional view of the input manifold of
the blade-thru condenser along line D-D of FIG. 14A.
[0033] FIG. 15 is a top view of the output manifold of the
blade-thru condenser of FIG. 9.
[0034] FIG. 15A is a cross-sectional view of the output manifold
along line A-A of FIG. 15.
[0035] FIG. 16 is a top view of the condenser core of the
blade-thru condenser of a further embodiment of the present
invention.
[0036] FIG. 16A is a perspective view of a spacer ring of the
condenser core of FIG. 16.
[0037] FIG. 16B is an enlarged top view of the aperture on the
floor of the condensation chamber on a blade of the condenser core
shown in FIG. 16.
[0038] FIG. 17 is a side view of a blade-thru condenser of one
embodiment of the present invention.
[0039] FIG. 18 is the test power circuit used in the Example.
[0040] FIGS. 19A and 19B are the test results of the performance of
an existing heat pipe.
[0041] FIGS. 20A and 20B are the test results of the performance of
the heat dissipation system of the present invention.
[0042] It is noted that in the drawings like numerals refer to like
components.
DETAILED DESCRIPTION OF THE INVENTION
[0043] In one aspect, the present invention provides a
phase-separated evaporator for enhancing the efficiency of an
evaporator in liquid-gas phase exchange process and the efficiency
of heat dissipation.
[0044] Referring to FIGS. 1 to 5, in one embodiment,
phase-separated evaporator 10 comprises a boiler plate 20 and a
phase separation chamber 40, as shown in FIGS. 3 and 4.
[0045] In the embodiment shown, boiler plate 20 has an upper
surface 22, a bottom surface 24, and a plurality of pins 30
extending upward from upper surface 22. Preferably, upper surface
22 and pins 30 are coated with a micro porous coating material.
Boiler plate 20 is made of a heat conductive material, preferably
metal, for example, copper. For use with an existing CPU, a boiler
plate can have a square shape with a dimension of about 40 cm
(centimeter) by about 40 cm. The micro porous coating material
coated area is about 30 cm by about 30 cm. In one embodiment, pins
30 have a square cross section, with a dimension of about 1 mm
(millimeter) by 1 mm and a height about 4 mm. However, pins 30 can
also have other geometries, such as rectangular, circular, or oval
in the cross section. Furthermore, a boiler plate coated with the
micro porous coating material, without pins, can also be used in
the evaporator of the present invention.
[0046] Phase separation chamber 40 comprises a housing 50 and a
phase partitioner 80. Housing 50 includes side walls 52, 54, 55a
and 55b, a top wall 70 and a base 60 connected to periphery 26 of
boiler plate 20. The top wall 70 inclines, from the first side wall
52 to the second side wall 54 along longitudinal axis 2, toward
boiler plate 20. As shown in FIG. 3, the first side wall 52 extends
beyond boiler plate 20 in the longitudinal direction, hence, phase
separation chamber 40 has a longitudinally extended section 42,
which provides an additional space for expansion of the vapor.
Housing 50 has a gas port 56 and a liquid port 58 positioned on
first side wall 52. In the configuration shown, base 60 has two
anchoring flanges, 62 and 64, each having an aperture 66 for
fastening the evaporator to the device which needs heat
dissipation.
[0047] Housing 50 is made of a thermal-insulating material, which
minimizes the conductive heat transfer from boiler plate 20 to
housing 50, in turn, minimizes the conductive heat transfer from
the evaporator to the connection conduits and the condenser used in
a heat dissipation system. In this sense, housing 50 is also
referred to as a decoupling chamber, as it thermally decouples the
evaporator from the condenser. The terms decoupling and decouple
used herein refer to the effect of inhibiting the conductive heat
transfer from the base of the evaporator which can be in a direct
contact with the heat source, such as the CPU of a computer,
through the walls of the housing of the evaporator, to the
condenser.
[0048] Furthermore, housing 50 insulates the heat inside the
evaporator from the environment, which maximizes the heat carried
out by the vapor. Suitable thermal-insulating materials include,
but are not limited to, ceramic, thermoplastic, for example, epoxy
plastic, diallyl phthalate, diallyl isophthalate, and phenolic
resin. Preferably, housing 50 has an integral single piece
structure, which can be produced by injection plastic molding.
[0049] In the embodiment shown, phase partitioner 80 includes a
partition panel 82 and a plurality of feeding injectors 90
extending from lower surface 86 of partition panel 82 toward upper
surface 22 of boiler plate 20. The periphery of phase partitioner
80 is hermetically connected to the interiors of the side walls of
housing 50, which divides phase-separated evaporator 10 into a
vapor directing compartment 6 and a condensate directing
compartment 8. Partition panel 82 also inclines from the first side
wall 52 to the second side wall 54 along longitudinal axis 2,
toward boiler plate 20, and is substantially in parallel with, and
adjacent to, top wall 70 of housing 50. To facilitate the
positioning of partition panel 82 within housing 50, housing 50 can
have a bossing around the interior of the side walls, so that
partition panel 82 can be conveniently disposed against the
bossing.
[0050] As shown in FIGS. 3 thru 5, partition panel 82 separates gas
port 56 and liquid port 58 into two compartments. Gas port 56 is in
communication only with vapor directing compartment 6 and liquid
port 58 is in communication only with condensate directing
compartment 8. As shown in FIGS. 6 and 7, partition panel 82
further includes an opening 89 functioning as a pressure vent for
balancing the pressure between vapor directing compartment 6 and
condensate directing compartment 8. Preferably, opening 89 is
positioned above the longitudinally extended section 42 beyond the
nucleated boiling surface on which the evaporation of the coolant
occurs, as described hereinafter.
[0051] Referring to FIGS. 6 thru 7 and 3, each feeding injector 90
has an injector inlet 92 communicating with upper surface 84 of
partition panel 82 and an opposing injector tip 94. In the
embodiment shown, feeding injector 90 tapers toward injector tip
94, with injector tip 94 disposed immediately above upper surface
22 of boiler plate 20. However, it should be understood that
feeding injectors without tapering can also be used.
[0052] In one embodiment shown in FIG. 8, boiler plate 20 has a
plurality of landing zones 28 on upper surface 22 among pins 30. In
the embodiment shown, a landing zone 28 is located at a regular
position of a pin within the array of pins 30, yet with a pin
removed or not present at such a location. Feeding injectors 90 are
disposed immediately above landing zones 28. With this
configuration, there is a sufficient space for each injector tip 94
among pins 30, which ensures no physical contact between feeding
injector 90 and adjacent pins 30. The surfaces of landing zones 28
are substantially free of micro porous coating material, and hence
it reduces bubble formation at these locations, and provides
effective receiving areas for the condensate.
[0053] Phase partitioner 80, inclusive feeding injectors 90, is
made of a thermal-insulating material, which minimizes the
conductive heat transfer through partition panel 82 between vapor
directing compartment 6 and condensate directing compartment 8.
Suitable thermal-insulating materials include those described above
for housing 50.
[0054] In a further aspect, the present invention provides a heat
dissipation system 100, which comprises phase-separated evaporator
10 of the present invention described above, a blade-thru condenser
200, and conduits connecting between the evaporator and the
condenser, as shown in FIG. 9. The system includes a fan 500
positioned next to the condenser, which blows ambient air through
the blades to remove the heat released from the condenser.
Preferably, the condenser is a blade-thru condenser as described
hereinafter. A blade-thru condenser has been described in detail in
co-pending U.S. patent application Ser. No. 11/494,238, which is
hereby incorporated by reference in its entirety.
[0055] However, the condenser can also be a conventional
tube-and-blade condenser. It should be understood that the
operational mechanism of the phase-separated evaporator of the
present invention is independent of the structure of the condenser,
although the performance of the heat dissipation system can be
affected by the structure and cooling capacity of a specific
condenser.
[0056] The heat dissipation system 100 further comprises an aqueous
coolant. Suitable coolants include, but are not limited to,
deionized water and refrigerant, such as refrigerant HFE7000
manufactured by 3M and Genetron.RTM. refrigerant 245FA manufactured
by Honeywell.
[0057] Preferably, two separate conduits, a vapor conduit 120 and a
condensate conduit 130 are used to connect phase-separated
evaporator 10 and condenser 200. The first end 122 of vapor conduit
120 is connected to gas port 56 of phase separation chamber 40, the
second end 124 of vapor conduit 120 is connected to an input
interface of condenser 200. The first end 132 of condensate conduit
130 is connected to an output interface of condenser 200 and the
second end 134 of condensate conduit 130 is connected to liquid
port 58 of phase separation chamber 40. In the embodiment shown,
vapor conduit 120 has a larger diameter for delivering gas.
[0058] Preferably, conduits 120 and 130 are made of flexible
material, such as corrugated stainless steel tubing, copper alloy
tubing, or other suitable materials, which provides the flexibility
of positioning the condenser. Furthermore, the material used for
the conduits is impermeable to the refrigerant, and is a poor heat
conducting material. Corrugated stainless steel tubing possesses
these preferred properties. Moreover, both conduits can be further
thermally insulated from the ambient environment to reduce heat
transfer between the conduits and the environment.
[0059] The operation of phase-separated evaporator 10 is described
hereinafter in reference to a system environment. Referring now to
FIGS. 3, 4 and 5, in operation a predetermined amount of an aqueous
coolant, for example deionized water comprising a surface active
agent, is placed into phase-separated evaporator 10 and the heat
dissipation system is sealed under the vacuum. Phase-separated
evaporator 10 is placed on a heat generating device that needs heat
dissipation, with bottom surface 24 of boiler plate 20 in direct
contact with a contact surface of the device, for example, placing
bottom surface 24 of boiler plate 20 on top of the die face of a
central processing unit (CPU) of a computer.
[0060] As the heat is transferred conductively through boiler plate
20, the coolant absorbs the heat and evaporates. This process
occurs on top of the micro porous coating material coated on the
upper surface 22 and pins 30, which is known as the nucleated
boiling process, hence, the coated surface is herein also referred
to as the nucleated boiling surface. The vapor generated inside
vapor directing compartment 6 exits from gas port 56, and enters
into condenser 200 through vapor conduit 120. The vapor releases
heat inside condenser 200, and is condensed into the liquid form
inside the condenser. Then, the condensate returns back to
phase-separated evaporator 10 through condensate conduit 130. The
condensate enters from liquid port 58 into condensate directing
compartment 8, therein it flows down on the inclined partition
panel 82. The condensate enters feeding injectors 90, as driven by
gravity, and injects from injector tips 94 onto landing zones 28 on
boiler plate 20. From the landing zones, the condensate diffuses on
the nucleated boiling surface by a capillary effect of the micro
porous coating material, and thereon absorbs heat and evaporates
again. As such, the evaporation and condensation processes
repeatedly continue within the heat dissipation system, which
effectively remove heat from the heat generating device to a
surrounding environment.
[0061] With regard to the feeding of the condensate from injector
tips 94 to landing zones, in addition to the gravity drive, it is
believed that there may be a localized differential pressure at the
landing zones, which may further facilitate feeding of the
condensate. In the process of nucleated boiling, when a bubble
leaves the pin immediately adjacent to a landing zone, a localized
vacuum is formed as the condensate rushes in to replace the space
of the bubble. This continuous liquid to gas conversion and liquid
replacement may cause a localized differential pressure around the
landing zone, which may have an inductive effect to the feeding of
condensate from an injector tip.
[0062] As described above, phase-separated evaporator 10 of the
present invention separates vapor and condensate into two
compartments within the evaporator. This profoundly enhances the
efficiency of the evaporator. In the phase-separated evaporator,
when the vapor exits from the evaporator, it is guided by vapor
directing compartment 6, without any physical contact with the
returning condensate; therefore, the vapor remains at its high
temperature and effectively carries heat into the condenser.
Furthermore, by separating the condensate from the vapor, the exit
of the vapor is not impeded by the counter flow turbulence caused
by the returning condensate. On the other hand, as the condensate
enters the evaporator, it is guided by condensate directing
compartment 8, without any physical contact with the rising vapor;
therefore, the condensate remains at its low temperature when it is
injected onto the boiler plate. Consequently, the phase-separated
evaporator of the present invention generates higher temperature
vapor as it leaves the evaporator and maintains lower temperature
condensate as it reaches the boiler plate in comparison to the
traditional evaporator. In other words, the phase-separated
evaporator maximizes the temperature difference (.DELTA.T) between
the out-bound vapor and the in-bound condensate. It can be
understood that the lower the temperature of the condensate is, the
faster the conductive heat transfers from the boiler plate to the
condensate, and more heat is absorbed in the process of
evaporation.
[0063] As well known in traditional evaporators, which only have
one chamber or compartment above the boiler plate, the rising vapor
encounters the returning condensate, and premature condensation of
the vapor occurs before it exits from the evaporator. On the other
hand, prior to the condensate reaches the boiler plate, the
condensate is already heated up by the vapor. Herein, the term
"premature condensation" refers to condensation of the vapor prior
to the vapor entering into the condenser. It can be appreciated
that using the phase-separated evaporator of the present invention,
without physical contact with the in-bound condensate, the
premature condensation of the out-bound vapor within the evaporator
is minimized. This maximizes the amount of heat carried by the
vapor out of the evaporator.
[0064] Furthermore, the space between top wall 70 and partition
panel 82 is very limited, and the condensate does not accumulate
within this space. Hence, the condensate has very short retention
time within condensate directing compartment 8 before being
delivered to boiler plate 20. This reduces heating of the
condensate by conductive heat transfer.
[0065] To further minimize the retention time of the condensate in
condensate directing compartment 8, partition panel 82 can further
include several condensate grooves (not shown) on upper surface 84,
connecting inlets 92 of feeding injectors 90 in the longitudinal
direction. The condensate grooves can start immediately next to
liquid port 58, and end at the lower edge of the inlet 92 of the
feeding injector 90 nearest to the second side wall 54. The
condensate grooves further guide the condensate into feeding
injectors 90, and minimize the retention of condensate in the area
around inlets 92. It should be understood that other suitable
configurations or arrangement to facilitate the delivery of
condensate into the feeding injectors can also be used for the
purpose of the present invention.
[0066] To facilitate efficient delivery of the condensate to the
boiler plate, injector tip 94 can have a meniscus cross section.
Because of the minimum distance between injector tip 94 and upper
surface 22 of boiler plate 20, for example 0.25 mm, the meniscus
shape eases the flow of the condensate, and also minimizes
disruption of the flow from the bubbles generated by the nucleated
boiling.
[0067] As shown in FIG. 10, the phase-separated evaporator shown in
FIGS. 1-5 can also be used with boiler plate 20 in a vertical
orientation. With certain computer configurations, the contact
surface of the CPU is in a vertical position, which requires a
vertical interface with the heat dissipation device. As shown in
FIG. 10, the functions of phase-separated evaporator 10 are
maintained in this orientation. The condensate flows down along the
top wall 70 of housing 50 and injects onto boiler plate 20 in a
horizontal direction as guided by feeding injectors 90.
[0068] In a further embodiment, feeding injectors 90 of partition
panel 82 may have different inner diameters, depending on the
locations of the feeding injectors. For example, for the vertical
orientation of the phase-separated evaporator, the feeding
injectors in a higher position, or more adjacent to the first side
wall 52, have a larger inner diameter; and the inner diameter of
the feeding injectors reduces gradually in a downward direction, or
more closed to the second side wall 54. Such a gradual reduction of
the inner diameter of the feeding injectors assists in controlling
the condensate flow when it is delivered to upper surface 22 of
boiler plate 20 to obtain more even distribution of the
condensate.
[0069] Depending on the arrangement between the phase-separated
evaporator and the condenser of the heat dissipation system, the
phase-separated evaporator can be configured differently. In an
alternative embodiment, a phase-separated evaporator 10A is
provided as shown in FIG. 11. In this configuration, top wall 70a
of housing 50a has two sections, an inclined section 72, which
covers substantially upper surface 22 of boiler plate 20 along
longitudinal axis 2a, and a port section 74, which is next to, and
vertically extending above, inclined section 72. The port section
74 has a connection wall 76 on one side, which connects with
inclined section 72. On the other side, the first side wall 52a of
housing 50a extends into the portion section 74, which is
substantially in parallel with connection wall 76, forming a
chimney-like structure. Liquid port 58a and gas port 56a are
positioned on top of port section 74 of top wall 70a. To provide
phase separation within phase separation chamber 40a, partition
panel 82a includes an inclined panel 81 substantially in parallel
with inclined section 72 of top wall 70a and a vertical section 83
extending from inclined panel 81 upwardly between connection wall
76 and first side wall 52a. The structure and orientation of
feeding injectors 90 are the same as described above in the phase
separation chamber 40. The opening 89a, or pressure vent, is
positioned on vertical section 83 of partition panel 82a between
condensate directing compartment and the vapor directing
compartment. With this configuration, liquid port 58a and gas port
56a, positioned on top wall 70a, can be connected to the condenser
by the vapor and condensate conduits, or can directly interface
with the inlet and the outlet of a condenser disposed above port
section 74.
[0070] Furthermore, the phase-separated evaporator 10A can also be
orientated with boiler plate 20 in the vertical position, in the
same manner shown in FIG. 10 of the evaporator 10. In this
orientation, the section of the condensate directing compartment
between connection wall 76 and vertical section 83 of partition
panel 82a can also function as a condensate reservoir.
[0071] The phase-separated evaporator of the present invention has
made a revolutionary breakthrough in the structure of an
evaporator. It has abandoned the conventional single chamber
structure, and for the first time, introduces phase separation
within the evaporator to direct the returned condensate directly
onto the boiler plate without encountering the exiting vapor. The
efficiency enhancement achieved by the instant phase-separated
evaporator contributes to the record-breaking heat dissipation
efficiency of the heat dissipation system of the present invention
as illustrated hereinafter in the example.
[0072] As stated above, in a preferred embodiment the heat
dissipation system of the present invention includes a blade-thru
condenser. The structure and operation mechanism of the blade-thru
condenser are described hereinafter.
[0073] Referring now to FIGS. 9, 12 and 13 thru 13B, in one
embodiment blade-thru condenser 200 comprises a condenser core 220,
a vapor input interface in the form of input manifold 300, and a
condensate output interface in the form of output manifold 400.
[0074] Condenser core 220 comprises a plurality of layers of blades
230 joined one on top of another along a longitudinal axis 212 of
condenser 200 by joint interfaces 240 formed between two adjacent
blades. Each layer of blades 230 has multiple chambers 250, herein
also referred to as condensation chambers. In the embodiment shown,
condensation chambers 250 are drawn chambers, which are formed
monolithically in each blade. On floor 252 of each condensation
chamber 250 there can be one or more apertures, or openings, 260,
which permit vapor and condensate to pass therethrough and cause
vibration of floor 252 of condensation chamber 250. As shown, a
plurality of layers of blades 230 are so aligned that floors 252 of
condensation chambers 250 of each layer of blade 230 are on top of
walls 256 of condensation chambers 250 of blade 230 immediately
underneath, thereby forming multiple phase exchange columns 280 in
parallel to longitudinal axis 212. In the embodiment shown, each
blade 230 of condenser core 220 includes three condensation
chambers. However, the number of condensation chambers can vary
depending on the desired capacity and/or size of the condenser. For
example, in a low capacity condenser, each blade can have only one
or two condenser chambers, and the condenser core has only one or
two phase exchange columns.
[0075] Blades 230 are made of heat conducting materials, preferably
metal, such as copper or aluminum. In an exemplary embodiment,
blade 230 is made of a copper blank. As shown, blades 230 are
substantially planar except the areas having the drawn chambers.
Between each two adjacent blades 230, there is a sufficient
distance for dissipating heat released from the blades by
convection driven by ambient air flow. In the exemplary embodiment
described above, the distance between two adjacent blades is about
1.5 mm.
[0076] To construct condenser core 220, multiple drawn chambers 250
(three are shown in FIG. 12) are formed monolithically in each
blade 230. Two apertures, 270 and 274, are fabricated on floor 252
of each drawn chamber 250. The cross sectional profile of a lower
portion of wall 256 of each drawn chamber 250 is configured to
interlock with a top portion 254 of the wall of drawn chamber 250
of the immediately underlying blade. FIG. 13A shows detailed
structure of a joint interface 240 between two immediately adjacent
blades 230 of one embodiment of the present invention, which can be
jointed together by soldering, adhesive, or other suitable means.
As shown, top portion 254 of wall 256 is a small planar recess,
which provides a seating rim to the condensation chamber 250 of the
blade immediately above.
[0077] It should be understood that in a preferred embodiment each
blade 230 has a monolithic structure. Each drawn chamber 250 is an
integral part of blade 230, and there is no interface of different
materials between drawn chamber 250 and the rest of blade 230. This
monolithic structure eliminates the metal to metal interfaces
between a tubular core and separate fins affixed thereto by
soldering or brazing, which are the interface structures used in
most conventional condensers, radiators and heat exchangers. These
metal to metal interfaces have intrinsically a significant thermal
resistance, and therefore, seriously hinder the heat transfer from
the tubular core to the fins.
[0078] Therefore, it can be understood that the term "blade-thru"
used herein refers to a structural feature wherein a monolithic
blade forms part of the chamber where the phase exchange of vapor
occurs, and the exterior fin. In the condenser so structured, along
each layer of blade there is no interface between different
materials at the transition point between the fin and the
condensation chamber which, in function, corresponds to part of the
conventional tubular core. Therefore, there is no hindrance to heat
transfer from the floor of the condensation chamber to the fin.
[0079] In one exemplary embodiment as shown in FIGS. 12 thru 13B,
condenser core 220 comprises about 40 planar blades 230,
interconnected together as described above. In the embodiment
shown, condensation chamber 250 has a circular shape with a
diameter about 12 mm. In this structure, apertures 260 include an
orifice 270 on one side of floor 252, and a semispherical aperture
274 on the other side of floor 252. The semispherical aperture 274
can be produced by partial piercing, which forms a reed flap 272.
It noted that reed flap 272 is part of semispherical aperture 274,
and in the context herein when the term of semispherical aperture
274 is used it refers to the aperture inclusive of the reed flap.
In the structure shown, orifice 270 is circular. In one embodiment,
orifice 270 has a diameter of 3 mm and semispherical aperture 274
has a height about 0.4 mm at the center of the aperture. However,
orifice 270 can also have other shapes or geometries, such as
elliptical, square, rectangular, triangle, elongated slot, etc.
Similarly, semispherical aperture 274 can also have various other
shapes and geometries; for example, an alternative aperture having
a reed can be produced by a knife edge formed by a narrow slot cut,
or other such cuts that produce a reed which can vibrate in a
passage of vapor flow. Furthermore, the reed flap can have a
different thickness between the edge portion and root portion that
is adjacent to the wall of the chamber, and typically, the edge
portion is thinner. In operation, the thinner the edge portion is,
the lower the vapor pressure that triggers the vibration. Moreover,
the temper, or hardness, of the metal also contributes to the
triggering threshold of the vibration and the frequency of the
vibration.
[0080] In the working environment of the blade-thru condenser of
the present invention, orifice 270 and semispherical aperture 274
are vibratory openings, which vibrate when vapor passes through the
apertures. In the hermetically sealed condenser 200, which is
connected to evaporator 10 by conduits, as vapor enters a phase
exchange column from the upper end of the condenser core, it
travels down the column by passing through orifice 270 and
semispherical aperture 274 in every condensation chamber. The vapor
flow, more specifically, the pressure difference between the upper
and lower sides of the floor of the condensation chamber, induces
vibration of the floor.
[0081] Between orifice 270 and semispherical aperture 274, the
vibration of semispherical aperture 274 can be initiated at a lower
vapor pressure, or a lower pressure difference between the upper
and lower sides of the floor. This can be appreciated by the fact
that a much lower pressure difference, which is also referred to as
differential pressure, can cause vibration of reed flap 272, hence,
induce the vibration of the floor. The vibrations of orifice 270
and semispherical aperture 274 are both in multiple frequencies,
yet can be in different frequency ranges. When both orifice 270 and
semispherical aperture 274 are present on the floor of condensation
chamber 250, as shown in FIGS. 12 and 13, the vibration can be
initiated by different vapor pressures, or pressure differences,
and the vibration frequencies also have a broader spectrum. This
results in an enhancement of heat exchange efficiency of the
condenser, as further described hereinafter. Moreover, it can be
appreciated that the vibration of the condensation chambers might
cause the vapor to pass the apertures in an oscillatory manner,
which in turn, could further enhance the vibration of the floors.
It should be understood that combinations of other suitable
aperture structures or configurations can also be used to achieve
the same effect.
[0082] Therefore, the term of vibratory opening or aperture used
herein refers to one or more apertures on a thin blade, which
vibrates when exposed to a passage of vapor flow or a differential
pressure. This is similar to the working mechanism of a Helmholtz
resonator.
[0083] Further details of the structure and operation of condenser
220 are described hereinafter in reference of FIGS. 12 and 13. As
shown, within one phase exchange column 280, the first blade 230
from the upper end of condenser core 220 has its orifice 270
aligned near semispherical aperture 274 of the second blade 230,
and its semispherical aperture 274 aligned near orifice 270 of the
second blade 230. In this sense, orifices 270 and semispherical
apertures 274 of two immediately adjacent blades 230 are
misaligned. However, orifices 270 and semispherical apertures 274
of every alternate layer of blades are in alignment, therefore, the
positioning of orifices 270 and semispherical apertures 274 is
bilaterally symmetric.
[0084] As vapor enters each phase exchange column from input
manifold 300, it passes through orifices 270 and semispherical
apertures 274 forming a vapor column, which causes vibration of
floor 252 of each condensation chamber 250. Furthermore, as can be
visualized in FIG. 13, with the bilaterally symmetric arrangement
within each phase exchange column 280, the vapor travels down with
a zig-zag pathway through orifices 270 and semispherical apertures
274, which forces the vapor to have a maximum contact with the
metal surface, and hence to achieve a maximum heat exchange between
the vapor and the metal. On the other hand, the angle of reed flap
272 also facilitates the condensate to flow down through
semispherical apertures 274 within the column. It should be
understood, however, that the bilaterally symmetric arrangement is
only one of possible arrangement of the vibratory apertures, and
various other structures and arrangements of the vibratory
apertures can be used for the purpose of the present invention.
[0085] In the process of continuous heat exchange inside the
condenser, the condensate formed in each condensation chamber flows
down within columns 280. The vibration of the chamber floor reduces
retention of the condensate within the condenser chamber.
Furthermore, it is known that the liquid film temporarily formed by
the condensate on the metal surface insulates the metal from a
direct contact with the vapor, which slows down the rate of heat
exchange between the vapor and the metal, therefore, could reduce
the heat exchange efficiency of the condenser. With the structure
and the operation mechanism of condenser core 220 of the present
invention, this film effect has been substantially reduced by the
vibration of the floor induced by the vibratory apertures in each
condensation chamber, as described above. The vibration reduces the
liquid film formation and retention on the surface of condenser
chamber, and hence, reduces the loss of heat exchange efficiency
caused by this film.
[0086] Moreover, it can be further appreciated when the metal
vibrates within the flow of the vapor, the effective surface
contact between the higher temperature vapor to the lower
temperature metal is maximized. Therefore, vibration of the metal
increases the heat transfer from the vapor to the metal beyond the
heat transfer that occurs in a static environment, because of the
increased effective surface contact between the metal and the
surrounding column of vapor.
[0087] As described above, the condenser core of the present
invention utilizes the monolithic and integral blade-thru structure
and preferably vibratory effect to substantially enhance heat
exchange efficiency, it is hence, also referred to as a blade-thru
Helmholtz condenser.
[0088] Fan 500 is positioned adjacent to condenser core 220, which
blows air through condenser core 220 in a direction transverse to
the longitudinal axis 212 of condenser core 220, to dissipate heat
released inside condenser core 220 into the surrounding
environment.
[0089] As shown in FIGS. 9 and 14 thru 14B, in one embodiment input
manifold 300 is in a form of a chamber, having a case 310 and a
base 320. Case 310 has a vapor inlet 312 to which the second end
124 of vapor conduit 120 is connected. There are multiple vapor
outlets 330a, 330b and 330c on base 320. As shown in FIG. 9, input
manifold 300 is disposed on top of condenser core 220, wherein each
vapor outlet is positioned directly above a condensation chamber
250 on the first blade 230 of condenser core 220, for directing
vapor into one column of condensation chambers 250 within condenser
core 220. As shown in FIGS. 14A and 14B, vapor outlets 330a, 330b
and 330c have different diameters. The diameter of the vapor outlet
increases with the distance of the outlet from vapor inlet 312,
which compensates the pressure difference due to the distance from
vapor inlet 312, and balances the amount of vapor entering into the
three columns of condensation chambers 250.
[0090] As shown in FIGS. 15 and 15A, output manifold 400 has a
similar, yet reversed structure of the input manifold 300, wherein
case 410 faces up and the lowest blade 230 is disposed on a top
panel 420. Output manifold 400 has multiple condensate inlets 430
on top panel 420. Each condensate inlet 430 is positioned directly
underneath one condensation chamber 250 of the lowest blade 230 of
condenser core 220. As shown in FIG. 15, a spacer ring 580 is
positioned on the top panel 420 around each condensate inlet 430.
Different from the vapor inlets of the input manifold, condensate
inlets 430 can have the same diameter, because at this location the
vapor has completely condensed and no pressure difference needs to
be compensated. Output manifold 400 has a condensate outlet 440 to
which the first end 132 of condensate conduit 130 is connected.
[0091] Input manifold 300 and output manifold 400 are preferably
made of a thermal-insulating material. The materials described
above for housing 50 of evaporator 10 can be used for making Input
manifold 300 and output manifold 400. In one exemplary embodiment,
LE grade Garolite sheet from McMaster Carr, Atlanta, Ga. is used.
This material is composed of several layers of fine weave cotton
fabric that is compressed, heated and cured in phenolic resin.
[0092] FIGS. 16 thru 17 show condenser core 220a of condenser 200a
of a further embodiment of the present invention, which has a
different condensation chamber structure and interface between
adjacent blades. Condenser 200a can have the same input manifold
300 and output manifold 400 described above. FIG. 16 shows a top
view of condenser core 220a. In this embodiment, blade 230a is
planar, and condensation chamber 550 is formed by placing a spacer
ring 580 around a radially extended multi-slot aperture 560. As
shown in FIG. 16A, spacer ring 580 has a height 582, which
separates two adjacent blades 230a. The condenser core 220a is
formed with a plurality of blades 230a stacking one on top another
along the longitudinal axis 212a, with spacer rings 580 in-between
each two adjacent blades 230a, as shown in FIG. 17.
[0093] Spacer ring 580 can be attached to blade 230a by soldering,
or by other suitable means. In one embodiment, spacer ring 580 is
made of stainless steel, which is a poor heat conductive material
in comparison to copper. Therefore, the heat transfer by conduction
between adjacent blades, other than by vapor, is reduced. This
further enhances the temperature difference between the top of
condenser core 220a where the vapor enters, and the bottom of
condenser core 220a where the condensate exits the condenser.
Consequently, the condensate produced has a low temperature, which
is not prematurely heated within the condenser by conductive heat
transfer between the blades through the space rings.
[0094] As shown in the enlarged view of FIG. 16B, multi-slot
aperture 560 has multiple slots 564 extending radially from a
center aperture 562. In this configuration, there are no separate
orifice and semispherical aperture as described above. Instead, the
radially extended multi-slot aperture 560 provides the passages for
both vapor and the condensate, and functions as a multi-frequency
resonator, as further described below. In condensation chamber 550,
the condensate flows down through the ends of slots 564 near spacer
ring 580, while the vapor passes through center aperture 562 and
the ends of slots 564 near center aperture 562.
[0095] As shown, multiple slots 564 have different lengths, for
example, the pair of opposing slots 564a is the longest and the
pair of opposing slots 564b is the shortest. This forms multiple
different reeds. Because of the length difference in the slots, one
reed 568 formed between two adjacent slots can have a different
triggering threshold for vibration or resonance in the pressurized
vapor from the triggering thresholds of other reeds. Some reeds
start to vibrate at a lower vapor pressure, and others start to
vibrate at a higher vapor pressure. With this configuration, the
vibration can be induced even under a relatively low vapor
pressure, such as under a condition where the heat generating
device has not reached very high temperature. This mechanism
broadens the effective operating range for initiating vibration,
which, in turn, enhances the efficiency of the condenser when the
heat generating device has yet reached an undesirable high
temperature.
[0096] It should be understood that other suitable structures or
configurations of the condensation chamber and the apertures on the
blades, which enable vibration in the presence of the vapor flow,
can also be used for the purpose of the present invention.
[0097] The operation mechanisms of the phase-separated evaporator
and the blade-thru condenser have been individually described
above. The operation of the heat dissipation system 100 of the
present invention is briefly described below from the perspective
of the whole system.
[0098] Vacuum is applied to heat dissipation system 100 to remove
air, then a predetermined amount of a coolant is placed into the
phase-separated evaporator 10 under vacuum, and the system is
sealed. It is noted that all connections between the evaporator and
the conduits, and between the condenser and the conduits are air
and liquid tight. In operation, when the refrigerants described
above are used, they evaporate at a temperature about 30.degree.
C., and the vapor pressure in evaporator 10 can be from about 10
psi to about 25 psi.
[0099] In general, the bottom surface 24 of boiler plate 20 is
placed in direct contact with a contact surface of a heating
generating device, for example, attached to the die face of a CPU
of a computer's motherboard for dissipating heat generated at the
CPU. In operation, as the heat is transferred conductively from the
CPU, or other heat generating devices, to boiler plate 20,
nucleated boiling occurs on top of the micro porous upper surface
22 and pins 30. The coolant absorbs heat, evaporates, and exits
from the vapor directing compartment 6. The vapor travels through
vapor conduit 120, enters input manifold 300, and then enters phase
exchange columns 280 of condenser core 220. As described above, the
high temperature and high pressure vapor passes through apertures
of condensation chambers 250, travels down in phase exchange
columns 280. Upon contacting with the blades, the vapor releases
heat and converts back into liquid condensate within phase exchange
columns 280. In this process, the vapor passes through the
apertures and causes vibration of the floor, which further
increases the heat exchange efficiency as described above. The
condensate formed exits from output manifold 400, flows through
condensate conduit 130, and then enters liquid port 58 of
condensate directing compartment 8 of phase-separated evaporator
10. The condensate fills into the plurality of feeding injectors
90, and dispenses onto the landing zones 28. The condensate
diffuses on the nucleated boiling surface of the boiler plate,
which is then heated up again by the heat absorbed from the CPU,
and is converted into vapor again.
[0100] As such, the evaporation and condensation processes continue
repetitively within heat dissipation system 100, and the phase
change from the liquid form to the gas form and from the gas form
back to the liquid form effectively removes heat from the CPU, or
other heat generating devices, to a surrounding environment.
[0101] Using two separate conduits in heat dissipation system 100
substantially reduces heat exchange between the vapor and the
condensate during their traveling between the evaporator and the
condenser. As the vapor leaves the evaporator, it enters vapor
conduit 120 without physical contact with the returning condensate;
therefore, the vapor remains at its high temperature and
effectively carries heat into the condenser. On the other hand, as
the condensate exits the condenser, it does not contact the rising
vapor; therefore, the condensate remains at its low temperature
when it returns back into the evaporator. Moreover, preferably,
both vapor conduit 120 and condensate conduit 130 are thermally
insulated from the ambient environment. Thermal insulation reduces
heat exchange between the vapor inside the vapor conduit and the
environment, and therefore, maximizes the heat carried by the vapor
into the condenser. Similarly, thermal insulation also reduces heat
exchange between the condensate and the environment, which
minimizes premature heating of condensate by the environment and
maintains the condensate at a low temperature as it enters the
evaporator.
[0102] An unprecedented heat dissipation efficiency has been
observed using the instant heat dissipation system. As illustrated
in the example below, using the heat dissipation system of the
present invention, the temperature of a simulated die face of CPU
was maintained below 55.degree. C. with an input power of 330 W for
simulating heat generation. In comparison, when an existing
commercial ThermalRight XP90C 4-tube heat pipe was used as the heat
dissipation device, the temperature of the same die face was
already about 60.degree. C. when the input power was only 170
W.
[0103] As further shown in FIGS. 19A and 20A, when expressed with
the heat resistance .theta.cs (C/W), using the instant heat
dissipation system the heat resistance of the simulated die face of
CPU was about 0.08 (C/W) when the input power was about 330 W,
while using ThermalRight XP90C, the heat resistance of the
simulated die face of CPU was about 0.22 (C/W) when the input power
was about 170 W. It is noted that the lower the heat resistance of
the die face of the CPU, the more effective the heat dissipation
device is.
[0104] Currently, the lowest heat resistance achieved by the
existing heat dissipation devices known in the art is about 0.12
(C/W). Therefore, the heat dissipation system of the present
invention has made a revolutionary breakthrough in terms of
efficiency and capacity in heat dissipation.
EXAMPLE
[0105] A prototype heat dissipation system was built, which
included a phase-separated evaporator, illustratively shown in FIG.
11, a blade-thru condenser comprising condenser core 220a (as
illustrated in FIGS. 16-17), a condensate conduit, and a vapor
conduit.
[0106] In the phase-separated evaporator, the boiler plate had a
square shape with a dimension of about 40 cm by about 40 cm. The
micro porous coating material coated area is about 30 cm by about
30 cm. The boiler plate had a matrix of 256 pins formed with 16
rows by 16 column pins, with 7 pins removed at the locations
corresponding to the 7 feeding injectors. The pins had a square
cross section, with a dimension of about 1 mm by 1 mm and a height
about 4 mm.
[0107] The housing and the partitioner were made of
thermal-insulating plastics then coated with an epoxy coating to
render the surface impermeable to the refrigerant. The boiler plate
was connected to the base of the housing of the phase-separated
evaporator by epoxy adhesive. The partitioner had 7 tapered feeding
injectors toward the boiler plate, immediately above the landing
zones located at the spaces formed by the removed pins.
[0108] In the condenser, the condenser core was constructed with 40
blades of copper blank. Each blade had a length about 127 mm, a
width about 44.5 mm, and a thickness about 0.17 mm. The blades were
substantially planar, and the distance between two adjacent blades
was about 1.5 mm.
[0109] On each blade, three multi-slot apertures as illustrated in
FIG. 16B were produced using wire EDM. Each slot had a width about
0.25 mm. The pair of longest slots (546a) had a total length of
about 18 mm, and the pair of shortest slots (546b) had a total
length of about 8 mm. Two positioning apertures (569) were provided
for each multi-slot aperture for alignment of the spacer ring.
[0110] The spacer rings were made of plastics, which had an oblong
shape, with a width of about 17 mm, a length of about 25 mm and a
height of about 1.5 mm. On the lower side of the spacer ring, there
were two positional bumps (not shown, about 0.5 mm in height)
complementary to the two positioning apertures (569) on the blade.
On the upper side of the spacer ring, there were two positional
dimples (567, about 0.5 mm in depth) complementary to the two
positional bumps on the lower side of the spacer rings. Two spacer
rings, above and below one blade, were aligned by inserting the
positioning bumps through the positioning apertures into the
positioning dimples underneath the blade. Each spacer ring was
attached to the blade by epoxy adhesive to form an air and liquid
tight connection. As such, three spacer rings were positioned
around the multi-slot apertures between every two adjacent blades,
and the process was repeated to form the condenser core.
[0111] The input manifold and output manifold were in a form of
rectangular case, hermetically sealed to the condenser core by
epoxy adhesive. The input manifold and output manifold were made of
thermal-insulating plastics and coated with epoxy.
[0112] Vacuum is applied to the hermetically sealed system through
a sealable opening on the condensate conduit, such as a valve, then
about 65 ml of Genetron.RTM. refrigerant 245FA from Honeywell was
added into the evaporator through the condensate conduit.
[0113] Heat dissipation efficiency of the heat dissipation system
described above was tested in comparison to a commercial
ThermalRight XP90C 4-tube heat pipe. The test used a variable AC
transformer (Variac) to apply an AC voltage to a heater cartridge,
which was in direct contact with the bottom surface of the boiler
plate. A current sense resistor allowed the current to be measured
with a voltmeter to avoid circuit path errors. Both voltage
measurements were performed with true RMS voltmeters. The fan was
powered by a precise 12.00V. The ambient air and the simulated die
face temperature were measured with thermocouples. The test power
circuit is illustrated in FIG. 18.
[0114] The test results using two different fan speeds (100 CFM and
79 CFM) are shown in FIGS. 19A thru 20B. FIGS. 19B and 20B show the
curves of input power to the heater cartridge vs. the temperature
of the simulated die face of a CPU. As shown in FIG. 19B, with the
fan speed of 100 CFM, when ThermalRight XP90C was used as the heat
dissipation device, the temperature of the simulated die face
reached about 60.degree. C. when the input wattage was 170 W.
However, as shown in FIG. 20B when the instant heat dissipation
system described above was used, the temperature of the simulated
die face was maintained below 55.degree. C., when the input wattage
to the heater cartridge was about 330 W, which was nearly double of
170 W.
[0115] FIGS. 19A and 20A show the curves of heat resistance
(.theta.cs) of the simulated die face of CPU vs. input power to the
heater cartridge. As shown in FIG. 19A, when ThermalRight XP90C was
used, with the fan speed of 100 CFM, the heat resistance .theta.cs
of the simulated die face of CPU was about 0.22 (C/W) when the
input power was about 170 W. As shown in FIG. 20A, when the instant
heat dissipation system described above was used, with the same fan
speed, the heat resistance of the simulated die face of CPU was
about 0.08 (C/W) when the input power was about 330 W.
[0116] The invention has been described with reference to
particularly preferred embodiments. It will be appreciated,
however, that various changes can be made without departing from
the spirit of the invention, and such changes are intended to fall
within the scope of the appended claims. While the present
invention has been described in detail and pictorially shown in the
accompanying drawings, these should not be construed as limitations
on the scope of the present invention, but rather as an
exemplification of preferred embodiments thereof. It will be
apparent, however, that various modifications and changes can be
made within the spirit and the scope of this invention as described
in the above specification and defined in the appended claims and
their legal equivalents. All patents and other publications cited
herein are expressly incorporated by reference.
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