Patent Application
20160102920
The following disclosure is directed generally to hybrid heat pipe assemblies.
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.
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.
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.
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.
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.
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.
Described herein are multiple example embodiments related to hybrid heat pipe assemblies.
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.
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.
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.
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.
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.
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.
Other features and aspects may be apparent from the following detailed description, the drawings and the claims.
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.
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.
While the devices 4 illustrated in
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.
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.
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
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
This application claims the benefit of U.S. Provisional Application No. 62/061,311, filed Oct. 8, 2014, which is fully incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62061311 | Oct 2014 | US |
