RELATED APPLICATIONS
FIELD OF THE INVENTION
[0002] The following disclosure is directed generally to hybrid heat pipe assemblies.
BACKGROUND OF THE INVENTION
[0003] A device usually generates heat as a result of losses in efficiency. A heat sink
is a passive heat exchanger that can cool a device by transferring heat generated
by the device into a surrounding cooling medium, such as air. A heat sink may have
a baseplate that can extract heat from a device that is in contact with the baseplate.
A heat sink may also include an assembly of fins bonded to the baseplate that can
transfer the extracted heat from the baseplate to the surrounding cooling medium.
Thus, there is a flow of heat from the device through the baseplate and the fins to
the surrounding cooling medium, thereby serving to cool the device in contact with
the baseplate.
[0004] Since the heat sink is a passive heat transfer mechanism, there may be situations
in which the heat sink is not able to adequately cool a device in contact therewith.
In such cases, a heat pipe apparatus might be applied. A heat pipe apparatus is also
a heat exchanger than can cool a device by transferring heat generated by the device
into a surrounding cooling medium. The heat pipe apparatus may include an evaporator
plate that can extract heat from a device that is in contact with the evaporator plate.
The apparatus may also include a plurality of heat pipes in contact with the evaporator
plate that can transfer heat from the evaporator plate to another location using liquid-to-vapor
phase changes.
[0005] Each of the heat pipes includes a working fluid, such as water, sealed in a long
thin walled cavity under vacuum. The cavity may be cylindrical or rectangular, but
is not limited thereto. When heat is applied to a portion of the heat pipe, the working
fluid boils and is converted into vapor. The vapor moves from the heated portion,
or an evaporating area, of the pipe to a lower temperature area, or a condensing area,
of the heat pipe via an adiabatic portion of the pipe where no phase change takes
place. The lower temperature area of the heat pipe is at an opposite end of the heat
pipe from the end of the heat pipe in contact with the evaporator plate. In the lower
temperature area of the heat pipe, the vapor will condense back into a liquid. The
liquid will move back to the heated area of the heat pipe via the adiabatic portion
of the pipe to be heated and evaporated again. Thus, a two-phase flow cycle is created.
[0006] The condensed liquid moves from the lower temperature area of the heat pipe to the
heated area of the heat pipe using gravity or a wicking structure. If the liquid moves
back to the heated area as a result of gravity, the heat pipe has been oriented in
such a way that gravity can draw the condensed liquid down toward the heated portion
of the heat pipe. For example, such an orientation may include a heat pipe being angled
downwardly from the lower temperature area of the heat pipe to the heated area of
the heated pipe. This allows gravity to draw the condensed liquid from the higher,
condensing area of the heat pipe toward the lower, evaporating area of the heat pipe.
[0007] A large fin stack is positioned around the lower temperature area, and possibly the
adiabatic portion, of the heat pipe. The fin stack can transfer the heat away from
the heat pipes into the air through forced or natural convection.
[0008] However, even such a heat pipe apparatus may not be effective to dissipate heat from
certain devices that are either exceedingly inefficient or of a size significant enough
to require a greater cooling capacity than such a heat pipe apparatus can provide
on its own.
SUMMARY OF THE INVENTION
[0009] Described herein are multiple example embodiments related to hybrid heat pipe assemblies.
[0010] In an aspect, a hybrid heat pipe is provided. The assembly includes a baseplate dimensioned
to be placed in surface contact with a device, the baseplate being configured to extract
heat from the device. The assembly additionally includes a plurality of fins bonded
to the baseplate, the fins being configured to transfer a first portion of the extracted
heat from the baseplate to air surrounding the fins. The assembly further includes
a complex heat pipe extending from the baseplate and having an end positioned within
the baseplate, the complex heat pipe being configured to receive and transfer a second
portion of the extracted heat transferred from the baseplate. Moreover, the assembly
includes a heat pipe fin stack to which the complex heat pipe is configured to transfer
the second portion of heat, the heat pipe fin stack being joined to the complex heat
pipe and configured to transfer the second portion of the extracted heat received
from the complex heat pipe to air surrounding the stack.
[0011] In an example of the aspect, the complex heat pipe extends from the baseplate and
through the fins and the heat pipe fin stack. In another example of the aspect, the
fins are bonded to the baseplate in a plurality of groups. The groups are separated
from each other by the complex heat pipe. In a further example of the aspect, the
complex heat pipe extends from the baseplate and through two of the fin groups and
the heat pipe fin stack. In an additional example of the aspect, each of the complex
heat pipes extends through the heat pipe fin stack.
[0012] In a further example of the aspect, the heat pipe fin stack includes a heat pipe
protective fin into which the complex heat pipe extends. The heat pipe protective
fin is positioned on an opposite side of the heat pipe fin stack from the fins. In
an example of the aspect, the heat pipe protective fin is positioned adjacent to one
end of the complex heat pipe. In yet another example of the aspect, another end of
the complex heat pipe is embedded in the baseplate.
[0013] In an additional example of the aspect, the fins are mounted to an opposite side
of the baseplate from a side of the baseplate in contact with the device. In still
another example of the aspect, the complex heat pipe is embedded in the baseplate.
In a further example of the aspect, the complex heat pipe extends at an angle from
the baseplate to an end of the complex heat pipe.
[0014] In a second aspect, a hybrid heat pipe assembly for cooling a device in contact is
provided. The assembly includes a baseplate dimensioned to be placed in surface contact
with a device, the baseplate being configured to extract heat from the device. The
assembly also includes a plurality of fins bonded to the baseplate, the fins being
configured to transfer a first portion of the extracted heat from the baseplate to
air surrounding the fins. The assembly further includes a complex heat pipe apparatus
positioned within the baseplate, the apparatus including a chamber positioned within
the baseplate and a plurality of complex heat pipes secured within the chamber, the
complex heat pipes extending from the baseplate and having ends positioned within
the baseplate, the chamber being configured to receive a second portion of the extracted
heat transferred from the baseplate and transfer the second heat portion to the complex
heat pipes, the complex heat pipes being configured to receive and transfer the second
heat portion from the chamber. The assembly additionally includes a heat pipe fin
stack to which the complex heat pipes are configured to transfer the second portion
of heat, the heat pipe fin stack being joined to the complex heat pipes and configured
to transfer the second portion of the extracted heat received from the complex heat
pipes to air surrounding the stack.
[0015] In an example of the aspect, the complex heat pipes extend from the chamber through
the fins and the heat pipe fin stack. In an additional example of the aspect, the
fins are bonded to the baseplate in a plurality of groups, and the groups are separated
from each other by the complex heat pipes. In a further example of the aspect, the
complex heat pipes extend from the chamber through two of the fin groups and the heat
pipe fin stack. In yet another example of the aspect, the chamber is mounted horizontally
in the baseplate. In another example of the aspect, the chamber is embedded in the
baseplate. In a still further example of the aspect, the chamber is positioned in
a baseplate channel comprising walls defining the baseplate channel, the chamber being
secured to the walls.
[0016] Other features and aspects may be apparent from the following detailed description,
the drawings and the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017]
FIG. 1 is a perspective view illustrating an example of a hybrid heat pipe assembly.
FIG. 2 is front view illustrating an example of the hybrid heat pipe assembly shown
in FIG. 1.
FIG. 3 is a side cross-sectional view taken along lines 3-3 of FIG. 2 illustrating
an example of the hybrid heat pipe assembly shown in FIG. 1.
FIG. 4 is a close-up view of area 4 of FIG. 3 illustrating an example of an interface
of a baseplate and a complex heat pipe of the hybrid heat pipe assembly shown in FIG.
1.
FIG. 5 is a perspective view illustrating an example of a complex heat pipe of the
hybrid heat pipe assembly shown in FIG. 1.
FIG. 6 is a perspective view illustrating an example of the hybrid heat pipe assembly
shown in FIG. 1 with devices in contact therewith.
[0018] Throughout the drawings and the detailed description, unless otherwise described,
the same drawing reference numerals will be understood to refer to the same elements,
features and structures. The relative size and depiction of these elements may be
exaggerated for clarity, illustration and convenience.
DETAILED DESCRIPTION
[0019] Examples incorporating one or more embodiments are described and illustrated in the
drawings. These illustrated examples are not intended to be limiting. For example,
one or more aspects of an embodiment may be utilized in other embodiments and even
other types of devices.
[0020] FIGS. 1-6 illustrate an example hybrid heat pipe assembly in surface contact with
a plurality of devices 4. While the devices 4 illustrated in FIG. 6 bear a common
resemblance with electronic modules, embodiments described herein are not limited
thereto. In fact, one having ordinary skill in the art may use the hybrid heat pipe
assembly 2 to cool any applicable heat-generating device having the ability to be
in contact with the hybrid heat pipe assembly 2.
[0021] While the devices 4 illustrated in FIG. 6 are mounted to the hybrid heat pipe assembly
2 using fasteners 6, embodiments described herein are not limited thereto. For example,
the devices 4 may merely be in contact with the hybrid heat pipe assembly 2 without
being fixed or mounted thereto. In addition, the devices 4 contacting the hybrid heat
pipe assembly 2 may be related or unrelated to each other. Moreover, the devices 4
may be in contact with or isolated from each other. Whatever the case, the devices
4 to be cooled by the hybrid heat pipe assembly 2 are positioned with respect to the
hybrid heat pipe assembly in such a way as to maximize surface contact with the hybrid
heat pipe assembly 2, thereby serving to increase an amount of heat extracted from
the devices 4 by the hybrid heat pipe assembly 2.
[0022] The illustrated hybrid heat pipe assembly 2 may combine various aspects and elements
of a bonded fin heat sink and a heat pipe apparatus. However, the hybrid heat pipe
assembly 2 is not limited thereto and can be further supplemented by other heat transfer
means known by those of ordinary skill in the art.
[0023] The example hybrid heat pipe assembly 2 described and illustrated herein includes
a baseplate 8 in contact with the devices 4, baseplate fins 10 bonded to the baseplate
8, a complex heat pipe 12 extending from the baseplate 8 and having an end positioned
within the baseplate 8, and a heat pipe fin stack 14 joined to the complex heat pipe
12.
[0024] The baseplate 8 is configured to extract heat from the devices 4 in contact with
the baseplate 8. As was previously noted with respect to the hybrid heat pipe assembly
2, while the devices 4 illustrated in FIG. 6 are mounted to the baseplate 8 using
fasteners 6, embodiments described herein are not limited thereto. For example, the
devices 4 may be in contact with the baseplate 8 without being fixed or mounted thereto.
In addition, the devices 4 may be related or unrelated to each other or other items
contacting the baseplate 8.
[0025] The baseplate 8 may have a shape consistent with that of a rectangular block. However,
embodiments disclosed herein are not limited thereto as the baseplate 8 can have any
shape or structure that is effective in cooling devices in contact therewith. Further,
while the baseplate 8 is illustrated in the example herein as being flat or planar,
embodiments described here are not limited thereto, as the baseplate 8 may be curved
or otherwise to maximize surface contact with the devices 4 and extract heat from
the devices 4 as efficiently as possible. Thus, the shape and design of the baseplate
8 may be adjusted for effective extraction of heat from whatever device might be in
surface contact therewith.
[0026] The baseplate 8 may be mounted on a corresponding structure such that an edge line
20 of the baseplate 8 is parallel with gravity. However, embodiments disclosed herein
are not limited thereto, as the baseplate 8 can be mounted in any plane particularly
suited for cooling the devices 4 in contact therewith, as long as requirements for
cooling the heat-generating devices 4 are met and acceptable support is provided for
the baseplate 8.
[0027] The heat extracted from the devices 4 by the baseplate 8 may be transferred therefrom
to the baseplate fins 10 bonded to the baseplate 8. The heat received by the baseplate
fins 10 may be directly transferred to the air surrounding the baseplate fins 10.
[0028] The baseplate fins 10 may be mounted directly on the baseplate 8 or on a fin plate
30 that is subsequently mounted on the baseplate 8. If mounted directly on the baseplate
8, each of the baseplate fins 10 may include a flange (not shown) via which the baseplate
fin 10 is fastened to the baseplate 8. The flange may extend from an edge of a body
32 of the baseplate fin 10 in a substantially perpendicular manner that is additionally
substantially parallel with the sides 16, 18 of the baseplate 8. The baseplate fins
10 may be bonded to the baseplate 8 in a plurality of groups. In addition, the baseplate
fins 10 may be mounted to an opposite side 16 of the baseplate 8 from a side 18 of
the baseplate 8 in contact with the devices 4.
[0029] In some cases, when cooling requirements for the devices 4 are great, the heat generated
by the devices 4 may be too substantial to be effectively dissipated solely by the
baseplate fins 10. When this occurs, the excess heat may be dissipated from the baseplate
8 through the complex heat pipe 12. The complex heat pipe 12 may transfer the received
excess heat from the baseplate 8 to the heat pipe fin stack 14 for subsequent dissipation
to air surrounding the heat pipe fin stack 14.
[0030] As is the case with the baseplate fins 10, the complex heat pipe 12 may also be positioned
on the opposite side 16 of the baseplate 8 from the side 18 of the baseplate 8 in
contact with the devices 4. In addition, the complex heat pipe 12 may be mounted on
the complex heat pipe side of the baseplate 8 in a location that corresponds with
a location of the devices 4 positioned on the opposite side 18 of the baseplate 8.
When the complex heat pipe 12 is mounted on the baseplate 8 in such a location, the
heat extraction from the devices 4 may be more efficient.
[0031] The complex heat pipe 12 may be similar in design to a clarinet heat pipe or a tube
that has been fabricated to seal a working fluid under vacuum pressure. Several complex
heat pipes 12 may be mounted in the baseplate 8 to extend therefrom. Ends of the complex
heat pipes 12 may also be embedded in the baseplate 8.
[0032] As such, a complex heat pipe 12 may separate one group of the baseplate fins 10 from
another group of the baseplate fins 10. The complex heat pipe 12 may extend from the
baseplate 8 and through the baseplate fins 10 and the heat pipe fin stack 14. The
baseplate fins 10 may be mounted to and arranged on the baseplate 8 in a plurality
of separated groups. In such cases, the groups of the baseplate fins 10 may be separated
from each other by a complex heat pipe 12 extending from the baseplate 8, between
the groups of the baseplate fins 10, and through the heat pipe fin stack 14. For example,
two groups of baseplate fins 10 may be separated by a complex heat pipe 12 mounted
to the baseplate 8 in an area between the two groups of the baseplate fins 10. The
complex heat pipe 12 may extend between and past the baseplate fins 10 and into the
heat pipe fin stack 14. The heat pipe fin stack 14 may be separated from the baseplate
8 by the baseplate fins 10.
[0033] Further, a complex heat pipe apparatus 22 may include a plurality of the complex
heat pipes 12 secured within a closed chamber 24 that is positioned within the baseplate
8. The complex heat pipes 12 may be secured within respective recesses in the closed
chamber 24 by brazing the heat pipes 12 to respective walls that define the recesses.
The chamber 24 may be embedded in a baseplate channel 26 formed within the baseplate
8 such that chamber 24 can fit therein. For example, the chamber 24 may be welded
to walls that define the baseplate channel 26. The closed chamber 24 may act as a
fluid reservoir within the baseplate 8 to expedite the transfer of heat from the baseplate
8 using a two-phase flow cycle created within the complex heat pipes 12.
[0034] Moreover, the closed chamber 24 may be mounted at a location in the baseplate 8 that
enhances or maximizes heat extraction from the devices 4. For example, the chamber
24 may be placed within a baseplate channel 26 at a location on the side 18 at which
the devices 4 make surface contact with the baseplate 8. The baseplate channel 26
location on the side 16 may be essentially opposite a location on the side 18 at which
the devices 4 are in surface contact therewith.
[0035] Further, the chamber 24 and the channel 26 may be correspondingly oriented to maximize
exposure to devices 4 in surface contact with the baseplate 8 in order to enhance
or maximize extraction of heat therefrom. For example, while both the chamber 24 and
the channel 26 are illustrated herein as being straight, embodiments disclosed herein
are not limited thereto, as the channel 24 can be correspondingly curved to a curved
channel 26 and of the baseplate 8 in order to maximize heat extraction from a correspondingly
positioned and/or shaped group of devices 4 making surface contact with the baseplate
8.
[0036] The heat pipe fin stack 14 may include a heat pipe protective fin 28 to provide protection
for a complex heat pipe 12 extending therethrough. The heat pipe protective fin 28
may be positioned on an opposite side of the heat pipe fin stack 14 from the baseplate
fins 10 and adjacent to one end 36 of the complex heat pipe 12. The pipe end 36 may
extend through the heat pipe protective fin 28, such that the pipe end 36 is separated
from a remainder of the complex heat pipe 12 by the heat pipe protective fin 28. Further,
an end cap 34 may be positioned on the pipe end 36 of the complex heat pipe 12 to
provide additional protection to the complex heat pipe 12.
[0037] In the examples described herein, the complex heat pipe 12 is positioned to absorb
excess heat from the baseplate 8 when cooling requirements are high enough that the
baseplate fins 10 are unable to effectively cool the devices 4 contacting the baseplate
8. As a result, melting of a devices 4 due to insufficient cooling may be inhibited.
[0038] A number of examples have been described above. Nevertheless, it will be understood
that various modifications may be made. For example, suitable results may be achieved
if the described elements are combined in a different manner and/or replaced or supplemented
by other elements or their equivalents. Accordingly, other implementations are within
the scope of the following claims.
1. A hybrid heat pipe assembly comprising:
a baseplate dimensioned to be placed in surface contact with a device, the baseplate
being configured to extract heat from the device;
a plurality of fins bonded to the baseplate, the fins being configured to transfer
a first portion of the extracted heat from the baseplate to air surrounding the fins;
a complex heat pipe extending from the baseplate and having an end positioned within
the baseplate, the complex heat pipe being configured to receive and transfer a second
portion of the extracted heat transferred from the baseplate; and
a heat pipe fin stack to which the complex heat pipe is configured to transfer the
second portion of heat, the heat pipe fin stack being joined to the complex heat pipe
and configured to transfer the second portion of the extracted heat received from
the complex heat pipe to air surrounding the stack.
2. The assembly of claim 1, wherein the complex heat pipe extends from the baseplate
and through the fins and the heat pipe fin stack.
3. The assembly of claim 1 or 2, wherein the fins are bonded to the baseplate in a plurality
of groups, and
wherein the groups are separated from each other by each complex heat pipe.
4. The assembly of claim 3, wherein the complex heat pipe extends from the baseplate
and through two of the fin groups and the heat pipe fin stack.
5. The assembly of any one of the previous claims, wherein the heat pipe fin stack is
separated from the baseplate by the fins.
6. The assembly of any one of the previous claims, wherein the fins are bonded to the
baseplate in a plurality of groups,
wherein the complex heat pipe is one of a plurality of complex heat pipes, and
wherein each of the complex heat pipes separates one of the fin groups from another
one of the fin groups.
7. The assembly of claim 6, wherein each of the complex heat pipes extends through the
heat pipe fin stack.
8. The assembly of any one of the previous claims, wherein the heat pipe fin stack comprises
a heat pipe protective fin into which the complex heat pipe extends, and
wherein the heat pipe protective fin is positioned on an opposite side of the heat
pipe fin stack from the fins.
9. The assembly of claim 8, wherein the heat pipe protective fin is positioned adjacent
to one end of the complex heat pipe.
10. The assembly of claim 9, wherein another end of the complex heat pipe is embedded
in the baseplate.
11. The assembly of any one of the previous claims, wherein the fins are mounted to an
opposite side of the plate from a side of the baseplate in contact with the device.
12. The assembly of any one of the previous claims, wherein the complex heat pipe is embedded
in the baseplate.
13. The assembly of claim 12, wherein the complex heat pipe extends at an angle from the
baseplate to an end of the complex heat pipe.
14. The assembly of any one of the previous claims, further comprising:
a complex heat pipe apparatus positioned within the baseplate, the apparatus comprising
a chamber positioned within the baseplate and a plurality of complex heat pipes secured
within the chamber, the complex heat pipes extending from the baseplate and having
ends positioned within the baseplate, the chamber being configured to receive a second
portion of the extracted heat transferred from the baseplate and transfer the second
heat portion to the complex heat pipes, the complex heat pipes being configured to
receive and transfer the second heat portion from the chamber;
wherein the complex heat pipes are configured to transfer the second portion of heat
to said heat pipe fin stack, the heat pipe fin stack being joined to the complex heat
pipes and configured to transfer the second portion of the extracted heat received
from the complex heat pipes to air surrounding the stack.
15. The assembly of claim 14, wherein the complex heat pipes extend from the chamber through
the fins and the heat pipe fin stack.