US20080230208A1

US20080230208A1 - Liquid Cooling System Cold Plate Assembly

Info

Publication number: US20080230208A1
Application number: US12/053,202
Authority: US
Inventors: Claus Nygaard Rasmussen
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-03-22
Filing date: 2008-03-21
Publication date: 2008-09-25

Abstract

A cold plate assembly (100) consisting of a base structure (102) having a high thermal transfer characteristic, which is adapted for contacting the surface of a heat source (10) on one side. A fluid transfer component (104), having a different thermal transfer characteristic is secured to the base (102) opposite from the heat source receiving side. The fluid transfer component (104) includes protrusions (106) adapted for placement into a flow of liquid coolant. A flow of liquid coolant is permitted to pass over the protrusions (106), but does not contact any portion of the base (102). Heat is then transferred from the heat source (10) through the base (102), into the fluid transfer component (104), and dissipated into the liquid coolant through the protrusions (106) which are immersed in the flow of liquid coolant passing through the chamber (105A) via an inlet (108A) and outlet (108B).

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is related to, and claims priority from, U.S. Provisional Patent Application Ser. No. 60/919,374 filed on Mar. 22, 2007, which is herein incorporated by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not Applicable.

BACKGROUND OF THE INVENTION

The present invention is related generally to liquid cooling systems adapted for use in cooling heat sources such as integrated circuit components, processors, and memory modules in a computer system, and in particular to a cold plate assembly configured for facilitating heat exchange between the heat source and a flow of cooling liquid.
Personal computer systems which are design for desktop or under-desk use, and which are typically characterized by a main-board or motherboard housed in a chassis or case, often provide one or more expansion slots into which auxiliary components may be installed. These auxiliary components may include network adapter circuit boards, modems, specialized adapters, and graphics display adapters. These auxiliary components may receive power through the connection to the motherboard, or through additional connections directly to a system power supply contained within the chassis or case. Additional components, such as hard drives, disk drives, media readers, etc. may further be contained within the chassis or case, and coupled to the system power supply and motherboard as needed.
During operation, the motherboard and various auxiliary components consume power and generate heat. To ensure proper functionality of the computer system, it is necessary to regulate the operating temperatures inside the environment of the chassis or case. Individual integrated circuits, especially memory modules and processors, may generate significant amounts of heat during operation, resulting in localized heat sources or hot spots within the chassis environment. The term “processors”, as used herein, and as understood by one of ordinary skill in the art, describes a wide range of components, which may include dedicated graphics processing units, microprocessors, microcontrollers, digital signal processors, and general system processors such as those manufactured and sold by Intel and AMD. Failure to maintain adequate temperature control throughout the chassis environment, and at individual integrated circuits, can significantly degrade the system performance and may eventually lead to component failure.
Traditionally, a cooling fan is often associated with the system power supply, to circulate air throughout the chassis environment, and to exchange the high temperature internal air with cooler external air. However, as personal computer systems include increasing numbers of individual components and integrated circuits, and applications become more demanding on additional processing components such as graphics display adapters, a system power supply cooling fan may be inadequate to maintain the necessary operating temperatures within the chassis environment.
Specialized liquid cooling systems are available for some components in a personal computer system. Specialized liquid cooling systems typically provide a liquid coolant circulation pathway, which routes a thermal transfer liquid between a heat exchanger such as a radiator and one or more heat source, such as a CPU, GPU, a memory module, a microprocessor, or transformer. At each heat source, the flow of liquid coolant is passed over a heat transfer component, commonly referred to as a cold plate, which is in contact with the heat source on one side, and the flow of liquid coolant on another side. Typically, a cold plate is constructed from a metal, such as copper, which has a good ability to transfer heat from the heat source to the liquid coolant. The surface of the cold plate in contact with the heat source is generally planar, facilitating a large region of contact, while the surface of the cold plate in contact with the liquid coolant flow may have a number of protrusions, fins, or foils extending there from to provide an increased surface area for the exchange of heat.
Being composed of metal, the cold plate is generally an expensive and heavy component in any liquid cooling system. For some metals, which are ideal heat transfer pathways, the formation of the protrusions, fins, or foils is difficult or time consuming. For example, to form a cold plate from copper, with the necessary protrusions to the required tolerances, a complex sintering process is required which is time consuming and expensive. With other types of metals, such as aluminum, the necessary protrusions may be readily formed at a reduced cost by a direct molding process, but lack the heat transfer characteristics of copper. If the two different types of metals are utilized in combination, it is possible that a galvanic corrosion may occur if each metal is in contact with the liquid coolant, leading to a failure of the liquid cooling system, either through corrosion buildup or leakage of the liquid coolant.
Accordingly, it would be advantageous to provide a cold plate assembly which is composed of two or more types of metal, which has a reduced manufacturing cost, an in which only a single type of metal is in contact with the liquid coolant, reducing the risk of galvanic corrosion.

BRIEF SUMMARY OF THE INVENTION

Briefly stated, the present disclosure provides a dual-metal cold plate assembly for use with a circulating liquid cooling system. The cold plate assembly consists of a base of first metal having a high thermal transfer characteristic, which is adapted for contacting the surface of a heat source on one side. A fluid transfer component, formed from a second metal, is secured to the base by soldering or welding, opposite from the heat source receiving side. The fluid transfer component includes numerous protrusions, fins, or pins opposite from the base, and is adapted for placement into a flow of liquid coolant. The cold plate assembly is retained within a housing, such that a flow of liquid coolant is permitted to pass over the numerous protrusions, fins, or pins of the fluid transfer component, but does not contact any portion of the base. Heat is then transferred from the heat source through the base, into the fluid transfer component, and dissipated into the liquid coolant through the various protrusions, fins, and/or pins which are immersed in the circulating flow of liquid coolant.
In an embodiment of the present invention, the base is formed from a solid copper disk, and the fluid transfer component is formed from molded aluminum, soldered to the base.
The foregoing features, and advantages set forth in the present disclosure as well as presently preferred embodiments will become more apparent from the reading of the following description in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the accompanying drawings which form part of the specification:

FIG. 1 is a side sectional view of a cold plate assembly of the present invention; and

FIG. 2 is a bottom view of the cold plate assembly of FIG. 1.

Corresponding reference numerals indicate corresponding parts throughout the several figures of the drawings. It is to be understood that the drawings are for illustrating the concepts set forth in the present disclosure and are not to scale.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The following detailed description illustrates the invention by way of example and not by way of limitation. The description enables one skilled in the art to make and use the present disclosure, and describes several embodiments, adaptations, variations, alternatives, and uses of the present disclosure, including what is presently believed to be the best mode of carrying out the present disclosure.
Turning to the Figures, a cold plate assembly 100 of the present invention adapted for secured over a heat source 10 such as an integrated circuit, video or graphic processing unit is shown configured for connection to an existing liquid cooling circulating flow loop via any suitable liquid pathway. Preferably the liquid cooling loop, which is not directly part of the present invention, provides all necessary components for circulating a flow of liquid coolant to and from the cold plate assembly 100 through inlets 108A and outlets 108B, thereby drawing heat away from the various heat-generating components 10 in proximity to the cold plate 100.
Preferably, the cold plate assembly 100 is made from materials which have a high conductivity to facilitate a transfer of heat, such as metals like copper or aluminum. The cold plate assembly 100 consists generally of a base structure or high thermal conductivity insert 102, a fluid transfer component 104, and a housing 105 which may optionally be integrally formed with the fluid transfer component 104. The base structure 102 is adapted for placement in contact with the surface of the heat source 10, and preferably consists of a high conductivity material which is adapted for contact with the heat source 10. Heat is transferred from the heat source 10 through the region of high conductivity material 102, such as copper, to the fluid transfer component 104. The fluid transfer component 104 is configured to transfer heat from the base structure 102 to a flow of liquid coolant which is circulated through a chamber 105A formed by the housing 105. The flow of liquid coolant enters the chamber 105A through one or more inlets 108A, and exits through one or more discharge outlets 108B.
The fluid transfer component 104 may include a plurality of radiating fins 106 or other structures extending within the chamber 105A to provide for an increase in the available surface area over which heat may be transferred to the flow of liquid coolant passing through the chamber 105A, and to direct the flow of liquid coolant about a circuitous path through the chamber 105A, maximizing heat absorption by liquid coolant.
The cold plate assembly 100 is operatively secured in contact with different types of heat sources 10 such as processors, memory modules, and graphic display cards by utilizing an exchangeable mounting clip structure or other bolt-on attachment means 110. Preferably the exchangeable mounting clip structure 110 is configured to facilitate attachment of the cold plate assembly 100 in operative proximity to the particular heat source 10. While the cold plate assembly shown in FIGS. 1 and 2 is generally cylindrical, having a circular base profile when viewed from the bottom, those of ordinary skill in the art will recognize that the specific shape and dimensions of the cold plate assembly 100, including the shape and dimensions of the base 102, may be varied depending upon the particular application for which the cold plate assembly 100 is intended to be utilized.
The base structure 102 of the cold plate assembly 100 is preferably a monolithic form of a single metal, such as a copper disk, and may be formed through any conventional manufacturing process to have at least one surface adapted for heat transfer from a heat source 10. A second surface of the base 102 is configured to be operatively bonded to the fluid transfer component 104, which is preferably formed from a second metal, such as aluminum. The base structure 102 may be bonded to the fluid transfer component 104 by any suitable bonding means, such as soldering, brazing, or welding.
By forming the fluid transfer component 104 and housing 105 from a second metal or heat conductive material which is different from the metal forming the base structure 102, the second metal or heat conductive material may be selected based in-part on the ease with which various protrusions, fins, radiator surfaces, or pins 106 may be formed into a surface of the fluid transfer component 104 for immersion in the flow of liquid coolant within the housing chamber 105A. For example, the second metal or heat conductive material may be selected to be aluminum, enabling the fluid transfer component 104, housing 105, and associated protrusions, fins, and radiator surfaces 106 to be formed from a molding or casting process. Since only the surfaces of the fluid transfer component 104 and housing 105 are exposed to the liquid coolant flow, the occurrence of galvanic reactions between the base structure 102 and the fluid transfer component 104 are reduced or eliminated.
As various changes could be made in the above constructions without departing from the scope of the disclosure, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Claims

1. A cold plate assembly for use with a liquid cooling system, comprising:

a base structure of first material having a high thermal transfer characteristic, said base structure adapted on at least one surface for contacting a heat source to facilitate a transfer of heat from said heat source to said base structure;

a fluid transfer component, said fluid transfer component formed from a second material having a second thermal transfer characteristic and adapted for partial immersion in a flow of liquid coolant on a first surface; and

wherein said fluid transfer component is coupled on a second surface, to a surface of said base structure to facilitate a thermal transfer of heat from the heat source, through said base structure and said fluid transfer component, to said flow of liquid coolant.

2. The cold plate assembly of claim 1 wherein at least one of said first and second materials is copper.

3. The cold plate assembly of claim 1 wherein at least one of said first and second materials is aluminum.

4. The cold plate assembly of claim 1 wherein said first material is copper, wherein said second material is aluminum.

5. The cold plate assembly of claim 1 wherein said base structure is coupled to said fluid transfer component by at least one of a bonding, welding, soldering, or brazing means.

6. The cold plate assembly of claim 1 wherein said fluid transfer component is a molded component.

7. The cold plate assembly of claim 1 wherein said fluid transfer component includes a plurality of protrusions on said first surface adapted for immersion in said flow of liquid coolant, said plurality of protrusions providing an increased surface area for an exchange of heat between said fluid transfer component and said flow of liquid coolant.

8. The cold plate assembly of claim 1 wherein said fluid transfer component includes a plurality of protrusions on said first surface adapted for immersion in said flow of liquid coolant, said plurality of protrusions directing a flow of liquid coolant within said fluid transfer component.

9. The cold plate assembly of claim 1 wherein said base structure is isolated from contact with said flow of liquid coolant by said fluid transfer component.

10. The cold plate assembly of claim 1 further including a housing defining an enclosed chamber over said first surface of said fluid transfer component, said housing including at least one inlet for receiving a flow of liquid coolant to said chamber, and at least one outlet for discharging a flow of liquid coolant from said chamber.

11. The cold plate assembly of claim 10 wherein said housing is integrally formed with said fluid transfer component.