U.S. patent application number 13/258994 was filed with the patent office on 2012-01-19 for heat sink with multiple vapor chambers.
This patent application is currently assigned to HEWLETT-PACKARD DEVELOPEMENT COMPANY L.P.. Invention is credited to Joseph R. Allen, Sarah Nicole Anthony, John P Franz.
Application Number | 20120012281 13/258994 |
Document ID | / |
Family ID | 44319607 |
Filed Date | 2012-01-19 |
United States Patent
Application |
20120012281 |
Kind Code |
A1 |
Franz; John P ; et
al. |
January 19, 2012 |
HEAT SINK WITH MULTIPLE VAPOR CHAMBERS
Abstract
A heat sink is disclosed. The heat sink comprises a base (102,
402) with at least one vapor chamber (208, 408) containing a fluid
with a first activation point. The base has at least one vapor
chamber (212, 412) containing a fluid with a second activation
point. The first activation point is different than the second
activation point.
Inventors: |
Franz; John P; (Houston,
TX) ; Anthony; Sarah Nicole; (Houston, TX) ;
Allen; Joseph R.; (Houston, TX) |
Assignee: |
HEWLETT-PACKARD DEVELOPEMENT
COMPANY L.P.
|
Family ID: |
44319607 |
Appl. No.: |
13/258994 |
Filed: |
January 26, 2010 |
PCT Filed: |
January 26, 2010 |
PCT NO: |
PCT/US10/22087 |
371 Date: |
September 22, 2011 |
Current U.S.
Class: |
165/104.26 ;
165/104.21 |
Current CPC
Class: |
H01L 23/427 20130101;
G06F 1/20 20130101; H01L 2924/0002 20130101; H01L 2924/0002
20130101; H01L 2924/00 20130101; G06F 2200/201 20130101 |
Class at
Publication: |
165/104.26 ;
165/104.21 |
International
Class: |
F28D 15/04 20060101
F28D015/04 |
Claims
1. A heat sink, comprising: a base; at least one vapor chamber
inside the base having a fluid with a first activation point; at
least one vapor chamber inside the base having a fluid with a
second activation point wherein the first activation point is
different than the second activation point.
2. The heat sink of claim 1, wherein the fluid with the first
activation point and the fluid with the second activation point are
the same fluid.
3. The heat sink of claim 1, wherein a volume of the least one
vapor chamber inside the base having a fluid with a first
activation point is larger than a volume of the at least one vapor
chamber inside the base having a fluid with a second activation
point.
4. The heat sink of claim 1, wherein the first activation point is
higher than the second activation point.
5. The heat sink of claim 1, wherein the at least one vapor chamber
inside the base having a fluid with a second activation point is
contained inside the at least one vapor chamber inside the base
having a fluid with a first activation point.
6. The heat sink of claim 1, wherein the at least one vapor chamber
inside the base having a fluid with a second activation point is
comprised of at least one heat pipe.
7. The heat sink of claim 1, wherein the at least one vapor chamber
inside the base having a fluid with a first activation point is
comprised of at least one heat pipe.
8. The heat sink of claim 1, wherein: the first activation point is
between 60 and 80 degrees C. and the second activation point is
between 35 and 65 degrees C.
9. The heat sink of claim 1, further comprising: a least one vapor
chamber inside the base having a fluid with a third activation
point wherein the third activation point is different than the
first or second activation point.
10. A method for cooling a component, comprising: activating a
fluid, inside a first vapor chamber in a heat sink mounted on the
component, at a first temperature; activating a fluid, inside a
second vapor chamber in the heat sink mounted on the component, at
a second temperature, wherein the first temperature is different
than the second temperature.
11. The method for cooling a component of claim 10, wherein the
fluid inside the first vapor chamber is a different fluid than the
fluid inside the second vapor chamber.
12. The method for cooling a component of claim 10, wherein a
volume of the first vapor chamber is larger than a volume of the
second vapor chamber.
13. The method for cooling a component of claim 10, wherein the
first vapor chamber and the second vapor chamber are heat
pipes.
14. The method for cooling a component of claim 10, wherein the
second vapor chamber is broken into at least two parts.
15. The method for cooling a component of claim 10, further
comprising: activating a fluid inside a third vapor chamber in the
heat sink mounted on the component at a third temperature, wherein
the third temperature is different than the first or second
temperature.
Description
BACKGROUND
[0001] Computer systems and servers generate large amounts of heat.
A significant portion of the heat generated in these systems comes
from individual electronic components mounted in the systems, for
example the central processing units (CPU). A heat sink is
typically mounted to the components to help remove the heat
generated by the component. As the chip densities of the components
have increased, the heat produced by the components has also
increased.
[0002] Some components operate at different power levels depending
on the current demands of the system. When the component is
operating at full power, it may generate large amounts of heat.
When operating at lower power, or when in a standby mode of
operation, the amount of heat generated may be significantly
reduced, compared to the high power condition. Constructing a heat
sink that efficiently removes the heat under all of the operating
condition of the component has become a challenge.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] FIG. 1 is a heat sink 100 in an example embodiment of the
invention.
[0004] FIG. 2 is an isometric cutaway view of heat sink 100, in an
example embodiment of the invention.
[0005] FIG. 3a is a sectional top view of heat sink 100 in an
example embodiment of the invention.
[0006] FIG. 3b is a sectional side view of heat sink 100 in an
example embodiment of the invention.
[0007] FIG. 4a is a sectional top view of heat sink 400 in an
example embodiment of the invention.
[0008] FIG. 4b is a sectional top view of heat sink 401 in an
example embodiment of the invention.
[0009] FIG. 4c is a sectional top view of heat sink 402 in an
example embodiment of the invention.
[0010] FIG. 4d is a sectional top view of heat sink 403 in an
example embodiment of the invention.
[0011] FIG. 4e is a sectional side view of heat sink 403 from FIG.
4d in an example embodiment of the invention.
DETAILED DESCRIPTION
[0012] FIGS. 1-4, and the following description depict specific
examples to teach those skilled in the art how to make and use the
best mode of the invention. For the purpose of teaching inventive
principles, some conventional aspects have been simplified or
omitted. Those skilled in the art will appreciate variations from
these examples that fall within the scope of the invention. Those
skilled in the art will appreciate that the features described
below can be combined in various ways to form multiple variations
of the invention. As a result, the invention is not limited to the
specific examples described below, but only by the claims and their
equivalents.
[0013] FIG. 1 is a heat sink 100 in an example embodiment of the
invention. Heat sink 100 is comprised of a base or body 102 and a
plurality of fins 104. Heat sink 100 may be constructed of any
material with a high thermal conductivity, for example copper,
platinum, aluminum, iron, etc. Fins 104 are formed on the top
surface of base 102 and are positioned in parallel rows with gaps
between the fins. In operation, air is typically forced through the
gaps between the parallel rows of fins to remove heat from heat
sink 100.
[0014] Heat sink 100 is typically positioned on top of a component
that requires cooling, for example component 106. In some example
embodiments of the invention, the bottom of heat sink 100 may have
a cavity sized to accept component 106 such that component 106
contacts heat sink 100 on the top and the four sides of component
106. A thermal grease may be placed between component 106 and heat
sink 100 to increase the thermal coupling between the two
parts.
[0015] FIG. 2 is an isometric cutaway view of heat sink 100, in an
example embodiment of the invention. Base 102 forms a first vapor
chamber 208. First vapor chamber 208 is rectangular and essentially
fills base 102. Positioned inside first vapor chamber 208 are two
hollow secondary structures 210. These two hollow structures form
two sealed secondary vapor chambers 212. In one example embodiment
of the invention, the volume of the first vapor chamber 208 is
larger than the combined volumes of the two secondary vapor
chambers 212. The first vapor chamber 208 contains a fluid with a
first boiling point. The two secondary vapor chambers 212 contain a
fluid with a second, different, boiling point. In one example
embodiment of the invention the boiling point of the fluid in the
first vapor chamber 208 is higher than the boiling point of the
fluid in the two secondary vapor chambers 212.
[0016] In operation, when the component 106 is operating at a lower
power or in a standby mode, the component 106 will dissipate a
first amount of power. When the component 106 is operating in a
high power mode, a second, higher amount of power will be
dissipated by the component 106. In general, a higher amount of
power dissipated by the component 106 will correspond to a higher
temperature at the base of the heat sink. When the secondary vapor
chambers 212 contain a fluid with a lower boiling point than the
fluid in the first vapor chamber 208, the fluid in the secondary
vapor chambers will boil at the lower power or standby operating
mode of the component. As the component dissipates more power, the
fluid in the secondary vapor chambers may saturate (i.e. never get
cool enough to condense). Once saturated, the fluid in a vapor
chamber has a lower capacity to transfer heat. The fluid in the
first vapor chamber (with a higher boiling point) will start to
boil as the temperature of the component increases. In this way the
fluid in the secondary vapor chambers transfers the heat from the
component across the heat sink during lower power operations. As
the temperature of the component increases, the fluid inside the
first vapor chamber is used to transfer the heat from the component
across the heat sink.
[0017] FIG. 3a is a sectional top view of heat sink 100 in an
example embodiment of the invention. Heat sink 100 comprises first
vapor chamber 208 and two secondary vapor chambers 212. Component
106 is positioned under heat sink 100. FIG. 3b is a sectional side
view of heat sink 100 in an example embodiment of the invention.
Arrows 318, 320, 322 and 324 in FIGS. 3a and 3b show the flow of
the first fluid inside vapor chamber 208. As component 106 heats
up, the first fluid begins to boil directly above component 106. As
the first fluid boils and turns into a vapor, the vapor rises as
shown by arrows 318 (FIG. 3b). The vapor moves across the top of
vapor chamber 208 as shown by arrows 320. As the vapor flows across
the top of vapor chamber 208, the heat contained in the vapor is
transferred into the top of heat sink 100. Air flowing past fins
104 removes the heat from heat sink 100. As the first fluid
transfers heat into the top of heat sink 1.00, the vapor cools and
condenses back into a fluid as shown by arrows 322. The cooled
fluid flow back to component 106, as shown by arrows 324, to begin
the cooling cycle again.
[0018] The second fluid inside the two secondary vapor chambers 212
follows a similar flow pattern. The fluid boils where the vapor
chambers are positioned over component 106 and the vapor condenses
as the vapor chambers moves away from component 106. When the
second fluid in the two secondary vapor chambers 212 has a lower
boiling point than the first fluid in the first vapor chamber 208
the second fluid will activate and boil at a lower temperature than
the first fluid.
[0019] In one example embodiment of the invention, the fluids
inside the first and second vapor chambers may be different working
fluids with different boiling points. For example, the fluid in the
first vapor chamber may be water and the fluid inside the secondary
vapor chambers may be alcohol. In another example embodiment of the
invention, the fluids inside the first and second vapor chambers
may be the same working fluid, but the different vapor chambers may
be filled with different volumes and pressures of the fluid to
adjust the boiling point of the fluids in the different vapor
chambers to activate at different power and temperatures. In
another example embodiment of the invention, the different vapor
chambers may have unique surface treatments and/or wicking
structures that modify the activation points of the fluids
contained in the vapor chamber. In one example embodiment of the
invention, the first activation point may be in the range of 35-65
degrees C., and the second activation point may be in the range of
60-80 degrees C.
[0020] Heat sink 100 is shown with the secondary vapor chamber 212
broken into two separate parts (see FIGS. 2 and 3) with two
separate volumes. In some example embodiments of the invention, the
secondary vapor chamber may be comprised of one or more separate
volumes. FIG. 4a is a sectional top view of heat sink 400 in an
example embodiment of the invention. Heat sink 400 has a first
vapor chamber 408 that fills heat sink base 402. A single secondary
vapor chamber 412 is shaped as a star and is centered over
component 406. The first vapor chamber 408 is filled with a fluid
having a first boiling or activation point. The second vapor
chamber 412 is filled with a fluid having a second, different
boiling or activation point.
[0021] FIG. 4b is a sectional top view of heat sink 401 in an
example embodiment of the invention. Heat sink 401 has a first
vapor chamber 408 that fills heat sink base 402. Four secondary
vapor chambers 412 arc positioned inside the first vapor chamber
408. The ends of the four secondary vapor chambers are positioned
over component 406. The first vapor chamber 408 is filled with a
fluid having a first boiling or activation point. The four
secondary vapor chambers 412 are filled with a fluid having a
second, different boiling or activation point in some example
embodiments of the invention, the secondary vapor chambers may
comprise heat pipes placed inside the first vapor chamber 408, with
the cold ends of the heat pipes positioned over component 406. In
other example embodiments, the secondary vapor chambers may be
structures formed into heat sink base 402.
[0022] In some example embodiments of the invention, the first
vapor chamber may be broken into more than one volume. FIG. 4c is a
sectional top view of heat sink 402 in an example embodiment of the
invention. Heat sink 402 has a first vapor chamber 408 that is
broken into three separate volumes (408a, 408b, and 408c). Heat
sink 402 also has the secondary vapor chamber 412 broken into two
separate volumes. The three separate volumes of the first vapor
chamber 408 are filled with a fluid having a first boiling or
activation point. The two secondary vapor chambers 412 are filled
with a fluid having a second, different boiling or activation
point.
[0023] FIG. 4d is a sectional top view of heat sink 403 in an
example embodiment of the invention. Heat sink 403 has the first
vapor chamber 408 broken into four separate parts or volumes and
the secondary vapor chamber 412 broken into two separate parts or
volumes. The four parts of the first vapor chamber 408 are formed
as separate parallel columns perpendicular to the long axis of
component 406. Two of the separate parts of the first vapor chamber
are placed over each end of component 406 with the other two
volumes places over the center of component 406. The two parts of
the secondary vapor chamber 412 are formed as separate parallel
columns perpendicular to the long axis of component 406. The two
separate volumes of the secondary vapor chamber are placed
in-between the two end volumes of the first vapor chamber and the
two center volumes of the first vapor chamber. In one example
embodiment of the invention, the four separate parts of the first
vapor chamber comprise four separate heat pipes, each having a
fluid with the same boiling or activation point. The two separate
volumes of the secondary vapor chamber comprise two separate heat
pipes have the same boiling or activation point, wherein the
boiling point of the fluid in the first vapor chamber is different
than the boiling point of the fluid in the secondary vapor chamber.
As can be seen by FIGS. 4c and 4d, the secondary vapor chambers may
not be contained inside the first vapor chamber.
[0024] FIG. 4e is a sectional side view of heat sink 403 from FIG.
4d in an example embodiment of the invention. Heat sink 403
comprises base 402, fins 404, vapor chambers 408 and vapor chambers
412. Heat sink 403 is positioned over component 406. Vapor chambers
408 and vapor chambers 412 are located in a chamber or cavity
centered over component 406. Vapor chambers 408 are four heat pipes
with a first activation temperature. Vapor chambers 412 are two
heat pipes with a second, different, activation temperature. In one
example embodiment of the invention, the first activation
temperature is higher than the second activation temperature.
[0025] In some example embodiments of the invention, the component
to be cooled may have more than two different power levels. For
example, the component may have a standby mode, a low power
operating point, and a high power operating point. In this example
embodiment of the invention there may be three or more vapor
chambers with different boiling or activation points. For example,
in FIG. 4c a first vapor chamber having a fluid with a first
boiling point may be comprised of volume 408b. A second vapor
chamber having a fluid with a second boiling point may be comprised
of volumes 408a and 408c. A third vapor chamber having a fluid with
a third boiling point may be comprised of the two separate volumes
412.
* * * * *