Abstract:
A system for cooling a component in a computer system is disclosed. The cooling system of the present invention comprises a heat collection chamber including an inlet opening and an outlet opening, wherein the inlet opening is located in a position vertically higher than a location of the outlet opening. The system includes a heat conductive jacket adapted to be in thermal contact with the component. The jacket includes an inlet port and an outlet port through which a cooling fluid circulates. The system also includes a first hollow tube for coupling the outlet port to the inlet opening, and a second hollow tube for coupling the outlet opening to the inlet port.

Description:
FIELD OF THE INVENTION 
     The present invention relates to cooling components in a computer system, and more particularly to a highly efficient system for cooling high heat generating components. 
     BACKGROUND OF THE INVENTION 
     As computer components evolve into more powerful devices, their power requirements consequently increase. With this increase in power consumption, a commensurate increase in power dissipation in the form of heat results. Microprocessors are a major source of heat in computer systems. One computer system might incorporate several microprocessors, thereby multiplying the amount of heat generated by the system. Moreover, the situation is compounded when several pieces of equipment are stored vertically in a rack, where each piece of equipment contains power consuming and heat generating components. 
     Heat dissipation is an important consideration in the design of modern-day computer systems. If heat is not adequately dissipated from the system, components may fail causing catastrophic damage to the system. To date, cooling systems have utilized finned heat sinks, augmented by axial flow fans mounted on the heat sink and/or air movers in the form of fans within or around the computer system. Nevertheless, as the amount of heat generated by the components increases, the current cooling systems will prove inadequate because larger heat sinks and/or fans will not fit into the already cramped space in and around a computer system. 
     Accordingly, a need exists for a more efficient system for cooling components in a computer system. The system should be compact, highly reliable, and cost effective. The present invention fulfills this need and provides related advantages. 
     SUMMARY OF THE INVENTION 
     A system for cooling a component in a computer system is disclosed. The cooling system of the present invention comprises a heat collection chamber including an inlet opening and an outlet opening, wherein the inlet opening is located in a position vertically higher than a location of the outlet opening. The system includes a heat conductive jacket adapted to be in thermal contact with the component. The jacket includes an inlet port and an outlet port through which a cooling fluid circulates. The system also includes a first hollow tube for coupling the outlet port to the inlet opening, and a second hollow tube for coupling the outlet opening to the inlet port. 
     Through the aspects of the present invention, the chassis of the computer system or equipment is advantageously used to dissipate heat generated from the enclosed components. By utilizing the present invention, heat sinks, and/or fans are eliminated. The present invention is reliable, and relatively easy to implement given the current related technology. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective of a computer system incorporating the cooling system in accordance with the preferred embodiment of the present invention. 
     FIG. 2 illustrates a perspective view of the heat conductive jacket attached to the microprocessor in accordance with the preferred embodiment of the present invention. 
     FIG. 3 is a cross sectional view of the heat collecting chamber in accordance with a first preferred embodiment of the present invention. 
     FIGS. 4A and 4B illustrate a second preferred embodiment of the heat collecting chamber in accordance with the present invention. 
     FIG. 5 is a schematic view of a third embodiment of the cooling system in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION 
     The present invention relates to cooling components in a computer system, and more particularly to a highly efficient system for cooling high heat generating components. The following description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements. Various modifications to the preferred embodiment and the generic principles and features described herein will be readily apparent to those skilled in the art. For instance, although the component in the preferred embodiment is a microprocessor, the present invention could be utilized for any heat generating component. Thus, the present invention is not intended to be limited to the embodiment shown but is to be accorded the widest scope consistent with the principles and features described herein. 
     In accordance with a preferred embodiment of the present invention, the component cooling system utilizes a heat conductive jacket affixed to the component, through which a cooling fluid is circulated. The cooling fluid absorbs heat generated from the component via the heat conductive jacket, and transfers the heat to a heat collection chamber formed out of the chassis enclosing the computer system. The heat is then dissipated into the environment directly through the chassis. The now cooled cooling fluid circulates back to the heat conductive jacket to repeat the process. 
     For a better understanding of the present invention, please refer to FIG. 1, which is a perspective of a computer system  100  incorporating the cooling system in accordance with the preferred embodiment of the present invention. The computer system  100  includes a planar  110 , onto which is coupled a microprocessor  120 . As stated above, the microprocessor generates heat, which must be dissipated. According to the preferred embodiment of the present invention, a heat conductive jacket  130  is placed in thermal contact with the microprocessor  120 . The heat conductive jacket  130  is adapted to allow a cooling fluid (not shown) to circulate through it, and is preferably made of copper, or any other suitable heat conductive material. 
     FIG. 2 illustrates a perspective view of the heat conductive jacket  130  attached to the microprocessor  120 . Preferably, a heat conductive adhesive  140  is disposed between the jacket  130  and the microprocessor  120  to secure one to the other. Two ports, an inlet port  150  and an outlet port  160 , are provided in the jacket  130  to allow the cooling fluid (not shown) to circulate into and out of the jacket  130 . Inlet port  150  and outlet port  160  are located at opposite corners of the jacket  130  to ensure that the cooling fluid flows across the entire surface of the microprocessor  120 . 
     Referring back to FIG. 1, a heat collecting chamber  180  is a closed space defined by the cavity formed between a portion of the chassis  105  and a second sheet  185  bonded thereto. The heat collecting chamber  180  is designed to receive the cooling fluid (not shown). FIG. 3 is a cross sectional view of the heat collecting chamber  180  in accordance with a first preferred embodiment. As is shown, the second sheet  185  is crimped at the top  185   a  and bottom  185   b  edges. Although not shown, the second sheet&#39;s  185  side edges are also crimped so that when the second sheet  185  is bonded to the chassis  105 , the heat collecting chamber  180  is sealed on all sides. The second sheet  185  can be bonded to the chassis  105 , for example, by spot welding techniques. 
     FIGS. 4A and 4B illustrate a second preferred embodiment of the heat collecting chamber  180 ′ in accordance with the present invention. The second sheet  185 ′ further includes a plurality of dimples, created, for example, by spot welds  188 . As is shown, a dimple  188  is an indentation in the sheet  185 .′ Along with the sheet&#39;s top  185   a , bottom  185   b , and side edges, the plurality of dimples  188  are bonded to the chassis  105 , for example by spot welding. FIG. 4B illustrates one dimple  188  spot welded to the chassis  105 . As FIG. 4B shows, by bonding the dimple  188  to the chassis  105 , the fluid path becomes disrupted, i.e., the cooling fluid must circulate around the bonded dimple  188 . This disruption causes turbulence, which, in turn, increases the heat transfer rate from the fluid to the chassis  105  and second sheet  185 ′. 
     In either embodiment, the second sheet  185 ,  185 ′ is a conventional sheet metal, and can be the same sheet metal used for the chassis  105 . Although the second sheet  185  is shown as an outer skin to the chassis  105 , it is also possible to bond the second sheet  185  to the inner surface of the chassis  105  to form the chamber  180 . Additionally, the creation of the “double wall” chamber  180  on the chassis  105  and/or the spot welding of dimples  188  increases the rigidity of the chassis  105 . Therefore, if desired, a lighter gage sheet metal can be used for the chassis  105  without sacrificing rigidity, thereby resulting in cost savings and weight savings. 
     Referring once again to FIG. 1, the heat collecting chamber  180  includes two openings, an inlet opening  190  and an outlet opening  195 . Each opening  190 ,  195  is preferably located at opposite ends of the chamber  180 . The vertical location of the outlet opening  195  is near the bottom  180   b  of the chamber  180 , while the vertical location of the inlet opening  190  is near the top  180   a  of the chamber  180 . The arrangement of the openings  190 ,  195  is important to the operation of the present invention, and will be discussed in more detail below. 
     A first hollow tube  170   a , such as a flexible plastic tube, connects the heat conductive jacket&#39;s outlet port  160  to the heat collecting chamber&#39;s inlet opening  190  and a second hollow tube  170   b  connects the chamber&#39;s outlet opening  195  to the jacket&#39;s inlet port  150 . Accordingly, the heat conductive jacket  130 , the first hollow tube  170   a , the second hollow tube  170   b  and the heat collecting chamber  180  form a closed loop, through which the cooling fluid (not shown) circulates in the direction of the arrows. 
     According to the preferred embodiment of the present invention, the cooling fluid is one which exhibits a high boiling point and a low freezing point, such as a 50/50 mixture of water and ethylene glycol. Furthermore, this 50/50 mix of water and ethylene glycol will protect the sheet metal chassis from corrosion. The cooling fluid enters the jacket  130  at a temperature T 1 . Heat generated by the microprocessor  120  is passed through the jacket  130  and absorbed by the cooling fluid, thereby raising the temperature of the cooling fluid to T 2 . The heated fluid circulates out of the jacket  130  and enters the heat collecting chamber  180 , where the fluid dissipates heat to the chassis  105  and second sheet  185 . As the fluid cools to T 1 , it sinks to the bottom  180   b  of the chamber  180  and circulates out of the chamber  180  through the outlet opening  195 , and back into the jacket  130 . 
     As stated above, the location of the heat collecting chamber&#39;s inlet opening  190  relative to the chamber&#39;s outlet opening  195  is important to the operation of the present invention. By locating the chamber&#39;s outlet opening  195  lower than the chamber&#39;s inlet opening  190 , the present invention takes advantage of a “thermal siphoning effect.” The principle underlying thermal siphoning is that heat rises, while cold sinks. Thus, by introducing the heated cooling fluid (at T 2 ) near the top  180   a  of the heat collecting chamber  180  via the inlet opening  190 , the fluid will tend to sink to the bottom  180   b  of the chamber  180  because as the fluid cools it becomes more dense. Accordingly, the cooling fluid circulates from the top  180   a  of the chamber  180  to its bottom  180   b  as it cools, and exits from the outlet opening  195  to return to the jacket  130 . 
     By utilizing the present invention, a portion of the chassis  105  of the computer system or equipment behaves as a heat sink to dissipate heat generated from the enclosed components. Moreover, the cooling system according to the preferred embodiment of the present invention operates naturally without the need for mechanical devices, such as a pump or a fan. 
     In addition, as shown schematically in FIG. 5, a pump  200  can be connected in series to the chamber  180  and a plurality of jackets  130 A- 130 D to enhance fluid circulation. The pump  200  is preferably a centrifugal pump typically used in automobile windshield wiper assemblies, which are small, cost efficient, and readily available commercially. As is shown, each jacket  130 - 130 D is coupled to a component (not shown), such as a microprocessor or any other heat generating component, and the jackets  130 A- 130 D are coupled to the closed loop in parallel. 
     Thus, the system of the present invention is compact and completely contained, and does not add to the overall size of the computer system. This feature is especially beneficial for rack mounted equipment, where racks are built to accommodate standard sized pieces of equipment and space is limited. As an added advantage, the “double-walled” chamber  180  increases the rigidity of the chassis. Therefore, a lighter gage sheet metal can be used for the chassis without sacrificing rigidity, thereby resulting in cost savings and weight savings. By judicious design of the heat collecting chamber  180 , an engineer can design-in stiffness, lightness and low cost. Finally, the present invention is reliable, relatively easy to implement and cost efficient because all of the parts are available commercially or easily machined. 
     Although the present invention has been described in accordance with the embodiments shown, one of ordinary skill in the art will readily recognize that there could be variations to the embodiments and those variations would be within the spirit and scope of the present invention. For instance, the heat conductive jacket can be attached to any heat generating component and is not limited to cooling microprocessors. Accordingly, many modifications may be made by one of ordinary skill in the art without departing from the spirit and scope of the appended claims.