US20060185831A1

US20060185831A1 - Heat exchanger assembly

Info

Publication number: US20060185831A1
Application number: US11/065,326
Authority: US
Inventors: David Moore; John Franz
Original assignee: Hewlett Packard Development Co LP
Current assignee: Hewlett Packard Development Co LP
Priority date: 2005-02-24
Filing date: 2005-02-24
Publication date: 2006-08-24

Abstract

A heat exchanger assembly for use in an electronic assembly having a heat source comprises a heat transfer section and heat dissipation fins. The heat transfer section includes a first portion attachable to the heat source and a second portion extending away from the first portion. The heat dissipation fins have a longitudinal dimension and are attached to at least part of the second portion of the heat transfer section along the longitudinal dimension.

Description

BACKGROUND

Heat generated by components within electronic devices/systems, such as computer systems, etc., must be transferred away from the components in order to ensure proper and efficient operation of these components. As the electronic systems and/or components become faster, smaller, more densely packed and/or more powerful, the amount or density of heat generated by the various components becomes greater. Likewise, the difficulty encountered in dissipating the heat from these components within the confines of the systems becomes greater. Consequently, electronic systems makers continue to pursue heat transfer technology or devices capable of satisfying the increased heat transfer requirements of new components and/or new systems.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top, front, left side perspective view of a computer system incorporating various embodiments of the present invention.
FIG. 2 is a top, front, left side perspective view of a heat exchanger assembly for use in a system, such as the computer system shown in FIG. 1, and incorporating an embodiment of the present invention.
FIG. 3 is a front view of folded metal heat dissipation fins for use in various embodiments of the present invention, such as the embodiments incorporated in the computer system shown in FIG. 1.
FIG. 4 is a front view of a portion of a heat exchanger assembly for use in a system, such as the computer system shown in FIG. 1, and incorporating an embodiment of the present invention.
FIG. 5 is a side view of a portion of a heat exchanger assembly for use in a system, such as the computer system shown in FIG. 1, and incorporating an embodiment of the present invention.
FIG. 6 is a top, front, left side perspective view of another heat exchanger assembly for use in a system, such as the computer system shown in FIG. 1, and incorporating another embodiment of the present invention.
FIG. 7 is a top, front, left side perspective view of a portion of the heat exchanger assembly shown in FIG. 6 and incorporating an embodiment of the present invention.
FIG. 8 is a top, front, left side perspective view of another portion of the heat exchanger assembly shown in FIG. 6 and incorporating an embodiment of the present invention.
FIG. 9 is a top, front, left side perspective view of an alternative structure of a portion of the heat exchanger assembly shown in FIG. 6 and incorporating an alternative embodiment of the present invention.

DETAILED DESCRIPTION

A computer system 100 incorporating various embodiments of the present invention is shown in FIG. 1 having elements such as a housing 102, a keyboard 104 and a display 106. A first heat exchanger assembly 108, incorporating a first embodiment, for transferring heat away from various components 110 of the computer system 100, is disposed at an appropriate location within the housing 102. A second heat exchanger assembly 112, incorporating a second embodiment, for transferring heat away from another component 114 of the computer system 100, is disposed at another appropriate location within the housing 102. The components 110 and 114 may be various appropriate heat sources, such as a processor, an IC (Integrated Circuit), an ASIC (Application Specific IC), a power supply, a hard drive, etc. The components 110 and 114 are typically mounted on a printed circuit board 116 within the housing 102. A vent 117 in the front of the housing 102 may permit air to flow into the housing 102 to cool the heat exchanger assemblies 108 and 112. Although the present invention is described with respect to its use in the computer system 100 and the heat exchanger assemblies 108 and 112, it is understood that the invention is not so limited, but may be used in any appropriate electronic system or assembly that includes a heat source with appropriate heat dissipation requirements and regardless of any other elements or components included in the electronic system.
The first heat exchanger assembly 108, according to the embodiment shown, generally includes heat transfer sections 118 and a central heat dissipation section 120. (See also FIG. 2.) The heat transfer sections 118 each include a first portion 122 that attaches to the components 110 and a second portion 124 that extends away from the first portion 122. Only one of the first portions 122, and thus only one complete heat transfer section 118, is shown in FIG. 2 for simplicity. The heat transfer sections 118 may be an evaporative-cycle closed-loop type of heat transfer device, such as a heat pipe, a vapor chamber, a radiator-type exchanger, a thermo-siphon, etc. In this manner, heat transfer through the heat transfer sections 118 from the components 110 to the heat dissipation section 120 is enhanced, because the evaporative-cycle closed-loop type heat transfer devices have a low thermal resistance in order to efficiently transport heat. Furthermore, the heat is effectively concentrated in one place, i.e. at the heat dissipation section 120, for more efficient cooling or dissipation. The size and lengths of the heat transfer sections 118 and the heat dissipation section 120 may depend on the amount of power or heat to be dissipated and the geometry of the specific situation.
The heat dissipation section 120, according to the embodiment shown, generally includes a number of sets of thermally conductive heat dissipation fins 126 with each set of heat dissipation fins 126 surrounded by an optional sleeve 128. The illustrated embodiment shows four sets of the heat dissipation fins 126, but it is understood that the invention is not so limited. Instead, any appropriate number of sets of heat dissipation fins 126 may be used.
The sleeves 128 duct airflow passed the heat dissipation fins 126. Additionally, one or more optional fans 130 may be positioned adjacent one end of the heat dissipation section 120 to flow the air through the sleeves 128 and passed the heat dissipation fins 126. Furthermore, each set of heat dissipation fins 126 is attached to a part of the second portion 124 of one of the heat transfer sections 118. In this manner, heat generated by the components 110 is transferred through the first portion 122 of the heat transfer sections 118, through the second portion 124 to the heat dissipation fins 126, where the heat is dissipated to the air flowing through the sleeves 128. Without the sleeves 128, much of the air still flows passed the heat dissipation fins 126, but is not specifically channeled to pass with maximum airflow next to the heat dissipation fins 126. With the sleeves 128, the airflow through the housing 102 or the number of fans used in the housing 102 may be reduced, thereby reducing fan noise and electrical power usage.
Additionally, the first heat exchanger assembly 108 may be removed and replaced for ease of manufacturing and/or servicing the first heat exchanger assembly 108 and/or the components 110. Alternatively, each set of heat dissipation fins 126, with or without the sleeves 128, may be individually removed and replaced.
An exemplary way to form a set of the heat dissipation fins 126 uses a folded metal fin structure 132, as shown in FIG. 3. (Other types of fin structures may also be used.) Each heat dissipation fin 126 is thus joined at the top and/or bottom with the next and/or previous heat dissipation fins 126 via top and bottom fin connections 134 and 136 between the heat dissipation fins 126. The folded metal fin structure 132 is wrapped around part of the second portion 124 of the heat transfer section 118, as shown in FIGS. 4 and 5. The bottom fin connections 136 are attached to the second portion 124, e.g. by soldering or other appropriate means, along a longitudinal dimension of both the heat dissipation fins 126 and the second portion 124. The heat dissipation fins 126, therefore, extend radially from the second portion 124. The bottom fin connections 136 must be of an appropriate size to fit all of the heat dissipation fins 126 onto the diameter of the second portion 124. Although the top fin connections 134 are shown as being approximately the same size as the bottom fin connections 136, the top fin connections 134 may be any appropriate length to permit airflow between each of the heat dissipation fins 126. Additionally, the fin configuration may have any appropriate longitudinal and radial dimensions.
The heat dissipation fins 126 are attached along the longitudinal dimension, rather than around the circumference of the second portion 124. In this manner, the heat dissipation fins 126 are parallel to the axis of the cylindrical second portion 124, rather than perpendicular to the axis. This configuration maximizes the contact between the heat dissipation fins 126 and the second portion 124 of the heat transfer section 118. In this manner, the transfer of heat from the second portion 124 through the heat dissipation fins 126 is also maximized.
Having the heat dissipation fins 126 attached to only part of the second portion 124 enables the heat dissipation fins 126 to be located away from the components 110. Thus, the components 110 can be laid out on the printed circuit board 116 without regard to the size of the heat dissipation fins 126 or other mechanical constraints related thereto. In this manner, components can be placed close together to maximize the use of the surface area of the printed circuit board 116 and/or to reduce electrical line length and propagation delay problems. Additionally, having the heat dissipation fins 126 located away from the components 110 enables the dissipation fins 126 to be placed adjacent an outer wall of the housing 102, where the air heated by the first heat exchanger assembly 108 can be dispelled directly out of the housing 102. Therefore, an almost direct thermal path is provided from the components 110 to the outside environment. Furthermore, having the heat dissipation fins 126 located away from the components 110 also minimizes restriction of airflow to other components within the housing 102 and enables removal of heat from the components 110 without heating the air used to cool the other components.
The second heat exchanger assembly 112, according to the embodiment shown, generally includes an inverted T-shaped heat transfer section 138 and heat dissipation fins 140, as shown in FIG. 6. The heat exchanger assembly 112 may also include an optional cover 142 surrounding the heat dissipation fins 140. The heat transfer section 138 and the heat dissipation fins 140 (and optionally the cover 142) may be made of any appropriate thermally conductive material. The cover 142 ducts the flow of air between the heat dissipation fins 140. In this manner, the airflow enters the second heat exchanger assembly 112 at one open end, e.g. the front 144, and exits at the other open end, e.g. the back 146.
The heat transfer section 138 generally includes a horizontal base 148 and a vertical section 150, both of which are substantially rectangular in shape. The horizontal base 148 may have optional small vertical fins 152 protruding therefrom.
The heat dissipation fins 140 and the vertical section 150 have a longitudinal dimension in the direction of arrow A, as shown in FIG. 7. The heat dissipation fins 140 are attached (e.g. by soldering, thermally conductive epoxy, etc.) to the vertical section 150 along the longitudinal dimension. Thus, the heat dissipation fins 140 extend horizontally from the vertical section 150, so the air flows horizontally across the heat dissipation fins 140. The folded metal fin structure 132 (FIG. 3) is an exemplary type of fin structure that may be used for the heat dissipation fins 140. (Other types of fin structures may also be used.)
According to a particular embodiment, the heat transfer section 138 generally includes a vapor chamber 154, as shown in FIG. 8. The vapor chamber 154 generally includes a portion 156 within the horizontal base 148 and a portion 158 within the vertical section 150. The vapor chamber 154 enhances heat transfer from the component 114 (FIG. 1) through the horizontal base 148 and into the vertical section 150, so the heat can be transferred to the heat dissipation fins 140 with minimal losses.
According to another particular embodiment, the heat transfer section 138 generally includes one or more embedded heat pipes 160, 162 and 164, as shown in FIG. 9. The embedded heat pipes 160 are vertical within the vertical section 150. The embedded heat pipe 162 is horizontal within the junction between the vertical section 150 and the horizontal base 148. The embedded heat pipes 164 are horizontal within the horizontal base 148. For simplicity, the embodiment in FIG. 8 shows the embedded heat pipes 164 in only one half of the horizontal base 148, but it is understood that additional such embedded heat pipes may be in the other half of the horizontal base 148. In much the same way that the vapor chamber 154 enhances heat transfer for the embodiment shown in FIG. 8, though perhaps not as efficiently, the heat pipes 160, 162 and 164 enhance heat transfer from the component 114 (FIG. 1) through the horizontal base 148 and into the vertical section 150.
Other embodiments having evaporative-cycle closed-loop type heat transfer means, in addition to those illustrated in FIGS. 8 and 9, may be incorporated in the heat transfer section 138. Additionally, variations on the embodiments shown in FIGS. 8 and 9 may have various different geometrical configurations or combinations of vapor chambers and/or embedded heat pipes, whether or not various parts of the vapor chambers and heat pipes are connected together as shown in FIGS. 8 and 9. Furthermore, some parts of the heat transfer section 138 may include a vapor chamber and/or an embedded heat pipe, while other parts of the heat transfer section 138 do not. Also, an alternative-embodiment heat transfer section 138 may have more than one vertical section 150.
The embodiments shown in FIGS. 8 and 9, and variations thereof, rapidly transfer heat from the component 114 (FIG. 1) through the horizontal base 148 and into the vertical section 150 of the heat transfer section 138. In this manner, the heat is quickly transferred to a surface area, i.e. the surfaces of the vertical section 150, where the heat can then be transferred to the heat dissipation fins 140 (FIGS. 6 and 7) for rapid dissipation to the air. The vertical section 150, therefore, enables a more efficient use of the space above the component 114 for heat dissipation than does (for example) a horizontal base section alone with vertical heat dissipation fins. The efficiency gain occurs because the usable surfaces of the vertical section 150 have a much larger area than the top surface of the horizontal base 148, so the distance between the hottest and coolest points on the heat dissipation fins 140 (i.e. the size of the heat dissipation fins 140) can be minimized and the contact area between the heat dissipation fins 140 and the surface of the vertical section 150 can be maximized. Additionally, due to the low heat loss characteristics of the evaporative-cycle closed-loop type heat transfer means and the presence of the vertical section 150, the second heat exchanger assembly 112 (FIG. 6) can be made taller with improved fin efficiency over prior solutions that may rely on a larger horizontal base for heat transfer. Having a smaller horizontal base 148 along with the vertical section 150, on the other hand, enables the components 114 to be laid out on the printed circuit board 116 (FIG. 1) with less regard to the size of the heat exchanger assembly 112 or other mechanical constraints related thereto. In this manner, the components 114 can be placed close to other components to maximize the use of the surface area of the printed circuit board 116 and/or to reduce electrical line length and propagation delay problems.
Furthermore, the horizontal base 148 and the vertical section 150 provide structural strength in x-y-z directions for the second heat exchanger assembly 112. Thus, the second heat exchanger assembly 112 has a robust structure that prevents shock and vibration problems and allows for strong retention methods to hold the second heat exchanger assembly 112 onto the component 114 (FIG. 1).

Claims

1. A heat exchanger assembly for use in an electronic assembly having a heat source comprising:

a heat transfer section including a first portion attachable to the heat source and a second portion extending away from the first portion; and

a set of heat dissipation fins, each heat dissipation fin having a longitudinal dimension and attached to at least part of the second portion of the heat transfer section along the longitudinal dimension.

2. A heat exchanger assembly as defined in claim 1 wherein:

the electronic assembly is a computer system.

3. A heat exchanger assembly as defined in claim 1 wherein:

the heat transfer section comprises an evaporative-type heat transfer device.

4. A heat exchanger assembly as defined in claim 3 wherein:

the second portion of the heat transfer section has a cylindrical shape; and

the heat dissipation fins extend radially away from the second portion.

5. A heat exchanger assembly as defined in claim 4 further comprising:

a cylindrical sleeve surrounding the heat dissipation fins to duct airflow passed the heat dissipation fins within the cylindrical sleeve.

6. A heat exchanger assembly as defined in claim 3 further comprising:

a fan positioned adjacent the heat dissipation fins to flow air passed the heat dissipation fins.

7. A heat exchanger assembly as defined in claim 3, wherein the electronic assembly has a plurality of the heat sources, further comprising:

a plurality of the heat transfer sections attached together, each including the first portion attachable to one of the heat sources and the second portion extending away from the first portion; and

a plurality of the sets of heat dissipation fins, each set of heat dissipation fins attached to at least part of the second portion of one of the heat transfer sections along the longitudinal dimension of the heat dissipation fins.

8. A heat exchanger assembly as defined in claim 3 wherein:

the first portion of the heat transfer section has a horizontal rectangular shape;

the second portion of the heat transfer section has a vertical rectangular shape; and

the heat dissipation fins extend horizontally from the second portion.

9. A heat exchanger assembly as defined in claim 8 wherein:

the first and second portions of the heat transfer section form an inverted T shape.

10. A heat exchanger assembly as defined in claim 8 further comprising:

a vapor chamber within the heat transfer section.

11. A heat exchanger assembly as defined in claim 8 further comprising:

at least one heat pipe embedded within the heat transfer section.

12. A heat exchanger assembly for use in a computer system having a heat source comprising:

a means for attaching to and receiving heat from the heat source;

a means for transferring the received heat to a location within the computer system remote from the heat source; and

a plurality of means for dissipating the transferred heat from the transferring means, the dissipating means each having a longitudinal dimension and being attached to the transferring means along the longitudinal dimension.

13. A computer system comprising:

a heat source; and

a heat exchanger assembly comprising:

a heat transfer section including a first portion attached to the heat source and a second portion extending away from the first portion and the heat source; and

heat dissipation fins having a longitudinal dimension and attached to at least part of the second portion of the heat transfer section along the longitudinal dimension.

14. A computer system as defined in claim 13 wherein:

the heat transfer section of the heat exchanger assembly comprises an evaporative-type heat transfer device.

15. A computer system as defined in claim 14 wherein:

the second portion of the heat transfer section comprises a cylindrical heat pipe; and

the heat dissipation fins extend radially out from the heat pipe.

16. A computer system as defined in claim 15 wherein:

the heat exchanger assembly further comprises:

a plurality of the heat transfer sections attached together.

17. A computer system as defined in claim 15 wherein:

the heat exchanger assembly further comprises:

a sleeve surrounding the heat dissipation fins to duct airflow passed the heat dissipation fins.

18. A computer system as defined in claim 15 wherein:

the heat exchanger assembly further comprises:

a fan adjacent the heat dissipation fins to flow air passed the heat dissipation fins.

19. A computer system as defined in claim 14 wherein:

the heat dissipation fins extend horizontally from the second portion.

20. A computer system as defined in claim 19 wherein:

the second portion of the heat transfer section comprises a vapor chamber.

21. A computer system as defined in claim 19 wherein:

the heat transfer section comprises at least one embedded heat pipe.