WO2012055924A1

WO2012055924A1 - Heat pipe system for cooling electronics

Info

Publication number: WO2012055924A1
Application number: PCT/EP2011/068781
Authority: WO
Inventors: Iver Munk
Original assignee: Tyst Design V/Iver Munk
Priority date: 2010-10-28
Filing date: 2011-10-26
Publication date: 2012-05-03

Abstract

A heat pipe system (1) for cooling electronic devices by transferring heat away from at least one heat producing entity (7), said heat pipe system (1) comprising at least one primary heat pipe (10) comprising an evaporator section (101) and a condenser section (102), and at least one distribution heat pipe (12) for distributing heat received from said at least one heat producing entity (7), and said at least one primary heat pipe (10) being adapted to being connected to said at least one distribution heat pipe (12), so that heat can be transferred between said primary heat pipe (10) and said distribution heat pipe (12) wherein that said evaporator section (101) and said condenser section (102) are separated by a distance, D, said evaporator section (101) and said condenser section (102) extending in a direction substantially parallel to each other. By constructing a web of heat pipes, heat may be more efficiently dissipated.

Description

Heat pipe system for cooling electronics

The present invention relates to a heat pipe system for cooiing electronic devices by transferring heat away from at least one heat producing entity, said heat pipe system comprising at least one primary heat pipe comprising an evaporator section and a condenser section, and at least one distribution heat pipe for distributing heat received from said at least one heat producing entity, and said at least one primary heat pipe being adapted to being connected to said at least one distribution heat pipe, so that heat can be transferred between said primary heat pipe and said distribution heat pipe.

Background of the invention

Heat pipes are widely use for cooling purposes in e.g. computers or other electronic devices. Heat pipes works by exploiting phase changes of a working fluid, such as acetone, in a closed circuit. A heat pipe comprises an evaporation portion and a condensation portion between which the working fluid moves due to among other reasons gravity and pressure differences. US Patent No. 6,189,601 discloses a heat sink for cooling electronic devices. The heat sink incorporates a finned member and a panel type heat pipe. The heat pipe transfers heat generated by a component to different parts of the finned member. When constructing heat pipe systems for use in e.g. a computer, it is desirable that the heat pipe system is as flexible as possible, in terms of allowing the heat pipe system to be adapted to the specific configuration of components inside the computer casing. An example in this regard is that the position of a heat generating central processing unit (CPU) varies from design to design. Bending and/or changing the shape of heat pipes may in many cases be inconvenient and undesirable due to among others the risk of destroying heat pipe functionality. Especially in off the self heat pipe system for non professional end users, the need for modification of heat pipes may advantageous be kept to a minimum. A heat pipe system easy to customize may however also contribute to reductions in production and/or assembly times in a professional setting.

Summary of the invention The invention is set forth and characterized in the main claim, while the dependent claims describe other characteristics of the invention.

The present invention seeks to provide a flexible heat pipe system easy to customize according to the specific use.

This is achieved by the heat pipe system wherein said evaporator section (101 ) and said condenser section (102) are separated by a distance, D, said evaporator section (101 ) and said condenser section (102) extending in a direction substantially parallel to each other.

An advantage in this respect is that a flexible system of heat pipes is obtained. By combining several heat pipes, the heat pipes can be positioned more freely while still being connected to e.g. the casing of an electronic device. By having a flexible system of heat pipes the need for bending and/or reshaping heat pipes may be reduced.

In one embodiment the evaporator section of the primary heat pipe is adapted to be arranged in connection with a heat producing entity and the primary heat pipe is adapted to transfer the heat from the evaporator section towards the condenser section and transfer the heat via the condenser section to the at least one distribution heat pipe. An advantage in this respect is that the primary heat pipe can be more freely positioned below the one or more distribution heat pipes. The one or more distribution heat pipes create a web through which heat can be distributed. The primary heat pipe establishes a heat transfer connection between heat producing entities and the distribution heat pipes.

Brief description of the drawings

In the following, the invention will be described in greater detail with reference to embodiments shown by the enclosed figures. It should be emphasized that the embodiments shown are used for example purposes only and should not be used to limit the scope of the invention.

Fig. 1 is an exploded view of a heat pipe system according to one

embodiment of the invention,

Fig. 2 is a cross-section of a mounted heat pipe system comprising a heat sink. Fig. 3a, b, c illustrates how the primary heat pipe can be positioned in various positions above e.g. an electronic device layout.

Detailed description A heat pipe system according to one embodiment of the invention will be described in the following with reference to the drawing.

The heat pipe system 1 comprises a primary heat pipe 10, a layer of top level heat pipes 12 and may also comprise a iayer of connection heat pipes 13. The heat pipes 10, 12, 13 are separate closed containers comprising a working fluid such as acetone but not limited hereto. The working fluid transfers heat from warm to colder regions by respectively evaporating and condensing. The working fluid may be transported inside the heat pipes by means of gravity, by utilizing a wick structure or by any other means known to the person skilled in the art,

In a section of a heat pipe where the heat pipe is heated, e.g. by a heat producing component, the working fluid evaporates to form a vapour or gas. The vapour is then transferred to a colder section of the heat pipe and condensate, thereby releasing the absorbed heat,

A section of a heat pipe where the working fluid evaporates will in the following be referred to as an evaporator section and a section of a heat pipe where the working fluid condensate will be referred to as a condenser section. Heat pipes have owing to their technical nature a flow direction. The flow direction of a heat pipe is determined by the location of the evaporation section in relation to the condensation section. The flow direction of a heat pipe is the direction in which the working fluid and/or vapour moves.

Now referring to fig. 3,a,b,c showing the primary heat pipe 10 in different positions above e.g. a mother board or other electronic layout. In electronic devices such as computers heat producing components may be located in different positions and the primary heat pipe 10 may be positioned

accordingly, The primary heat pipe 10 may be positioned with its evaporator section 101 adjacent a heat producing component 7 such as a computer chip, CPU etc. as shown in fig. 2. The primary heat pipe 10 has a substantially planar and horizontal evaporator section 101 and a substantially planar and horizontal condenser section 102. The evaporator section 101 and the condenser section 102 are mutual overlapping, parallel and separated by a distance, D. The evaporator section 101 is fluidly connected to the condenser section 102 by a connecting portion 103, The connecting portion 103 has an inclining angular position and slopes away from evaporator section 101 . The angle, X as defined in fig. 2 may thus be above ninety degrees and the angle, Y between the condenser section 102 and the connecting portion 103 may be below ninety degrees. View from the side, the primary heat pipe 10 has a U- shaped form, and the evaporator section 101 and condenser section 102 will be overlapping.

The primary heat pipe 10 has a substantially planar and horizontal evaporator section 101 and a substantially planar and horizontal condenser section 102. The evaporator section 101 and the condenser section 102 are parallel and separated by a distance, D, but not overlapping or only partly overlapping, depending on the angle X being an acute or an obtuse angle. Thereby, viewed from the side, the primary heat pipe has an S or Z-shaped form.

When the angle X is an obtuse angle, the evaporator section 101 and condenser section 102 will not be overlapping, and the primary heat pipe will have an S-shaped form. When the angle X is an acute angle, the evaporator section 101 and the condenser section 102 will be partly overlapping, and the primary heat pipe will have a Z-shaped form.

Still referring to fig. 2 the condenser section 102 of the primary heat pipe 10 is connected to one or more of the distribution heat pipes 12. The condenser section 102 and thereby the primary heat pipe 10 is held in place by a mounting plate 6 secured to a cooling member 14 via bolts 6.

The distribution heat pipes 12 may be arranged in grooves in the cooling member 14, with the exposed surface of the distribution heat pipes 12 in flush with the underside of the cooling member 14. The distribution heat pipes 12 may be arranged such that their flow direction is substantially perpendicular to the flow direction of the primary heat pipe 10.

The layer of one or more connection heat pipes 13 may be arranged below the distribution heat pipes 12, In the embodiment shown in fig. 1 and 2, two connection heat pipes are arranged such that they connect opposite ends of the shown distribution heat pipes 12. The flow direction of the connection heat pipes 13 is substantially perpendicular to the flow direction of the distribution pipes 12. Hereby a web of interconnected heat pipes is created.

The cooling member 14 may be the chassis of a computer casing, a heat sink or any other surface or element suitable for cooling a part of the system of heat pipes. The cooling member shown in fig. 2 has multiple substantially perpendicular extending fins. The fins increase the surface area of the cooling member, thereby enhancing heat dissipation properties.

Having described the device in detail, its use and operation will be described in further detail below.

The primary heat pipe 10 transfers heat away from a heat producing area or component 7. The primary heat pipe 10 is connected to a cooling member 14, preferably via a web of distribution heat pipes 12 and/or connection heat pipes 13. Heat received at the evaporator section 101 may be transferred via the connecting portion 103 to the condenser section 102. From the condenser section 102, heat may be transferred to one or more distribution heat pipes 12. Inside the one or more distribution heat pipes 12 the working fluid evaporates under influence of the heat from the primary heat pipe 10. Vapour or gas is distributed in the distribution heat pipes, thereby transferring heat to colder sections. Several condenser sections are thereby created in the distribution heat pipes 12. Via these condenser sections heat may de transferred to the cooling member 14 and/or connection heat pipes 13. The primary function of the level of connection heat pipes 13 is to distribute heat more evenly. If for instance more heat is transferred to one distribution heat pipe than the other, the connection heat pipes 13 may transfer heat between the distribution heat pipes 12 to reduce these differences. Hereby the utilization of the web of heat pipes is optimized,

The surface area of said condenser section (102) of said primary heat pipe (10) is larger than the surface area of said evaporator section (101 ) of said primary heat pipe (10), The surface area of said condenser section (102) can be two, three and four or even up to seven times the size of the surface area of said evaporator section (101 ).

When building e.g. a computer or other electronic device heat producing components may be arranged differently from time to time. When the electronic layout has been completed one or more primary heat pipes 10 may be arranged in connection with heat producing components. The evaporator section 101 of a primary heat pipe 10 may be arranged directly on top of e.g. a computer chip or alternatively a shield or other heat-conducting material may be positioned in-between. The positioning of the one or more primary heat pipes 10 is very flexible due to the web of distribution heat pipes 12, As the one or more primary heat pipes 10 are moved around, they will be in contact with one or more different distribution heat pipes 12. It is to be noted that the figures and the above description have shown the example embodiments in a simple and schematic manner. Internal electronic and mechanical details have not been shown since the person skilled in the art should be familiar with these details and they would just unnecessarily complicate this description.

Claims

aims

1 . A heat pipe system (1 ) for cooling electronic devices by transferring heat away from at least one heat producing entity (7), said heat pipe system (1 ) comprising;

• at least one primary heat pipe (10) comprising an evaporator section (101 ) and a condenser section (102), and

• at least one distribution heat pipe (12) for distributing heat received from said at least one heat producing entity (7), and

• said at least one primary heat pipe (10) being adapted to being connected to said at least one distribution heat pipe (12), so that heat can be transferred between said primary heat pipe (10) and said distribution heat pipe (12) characterized in that said evaporator section (101 ) and said condenser section (102) are separated by a distance, D, said evaporator section (101 ) and said condenser section (102) extending in a direction substantially parallel to each other.

2. A heat pipe system (1 ) according to claim 1 , wherein said evaporator section (101 ) and said condenser section (102) are parallel and partially or fully overlapping.

3. A heat pipe system (1 ) according to any one of the preceding claims, wherein said primary heat pipe (10) and/or said distribution heat pipe (12) have/has substantially planar surfaces.

4. A heat pipe system (1 ) according to any one of the preceding claims, wherein said evaporator section (101 ) of said primary heat pipe (10) is adapted to be arranged in connection with a heat producing entity (7); said primary heat pipe (10) being adapted to transfer said heat from said evaporator section (101 ) towards said condenser section (102) and transfer said heat via said condenser section (102) to said at least one distribution heat pipe (12).

5. A heat pipe system (1 ) according to any one of the preceding claims, wherein a surface area of said condenser section (102) of said primary heat pipe (10) is larger than a surface area of said evaporator section (101 ) of said primary heat pipe (10).

6. A heat pipe system (1 ) according to any one of the preceding claims, wherein a surface area of said condenser section (102) is between three and seven times the size of the surface area of said evaporator section (101 ).

7. A heat pipe system (1 ) according to any one of the preceding claims, wherein said condenser section (102) of said primary heat pipe (10) is adapted to be connected to at least two distribution heat pipes (12).

8. A heat pipe system (1 ) according to any one of the preceding claims, wherein a connection portion (103) connecting said evaporator section (101 ) and said condenser section (102) together with said condenser section (102) defines an angle below 90 degrees, and wherein a distance D between said evaporator section (101 ) and said condenser section (102) may be varied by changing said angle.

9. A heat pipe system (1 ) according to any one of the preceding claims, said heat pipe system (1 ) further comprising a mounting plate (1 1 ) adapted to receive and secure said primary heat pipe (10).

10. A heat pipe system (1 ) according to any one of the preceding claims, said heat pipe system (1 ) further comprising at least one connection heat pipe (13) adapted to be connected to at least two distribution heat pipes (12),

1 1. A heat pipe system (1 ) according to any one of the preceding claims, said heat pipe system (1 ) further comprising a cooling member (14) comprising one or more grooves for receiving said one or more distribution heat pipes (12).

12. A heat pipe system (1 ) according to any one of the preceding claims, wherein a flow direction of said distribution heat pipe (12) is

substantially perpendicular to a flow direction of said primary heat pipe