WO2008105666A1

WO2008105666A1 - Cooling system for personal computer

Info

Publication number: WO2008105666A1
Application number: PCT/NO2008/000068
Authority: WO
Inventors: Ole Petter Hornsletten
Original assignee: Devotech As
Priority date: 2007-02-27
Filing date: 2008-02-22
Publication date: 2008-09-04

Abstract

A cooling system for Personal Computing systems (PC) comprises star connection or parallel distribution of a cooling agent to a plurality of cooling devices (20) from a distributing element (11). A reservoir (10) is in fluid communication with a pumping device (11) providing a slight excess pressure in the distributing element (11). The cooling agent is collected via a collecting element (13).

Description

Cooling system for personal computer.

The present invention is generally related to the field of cooling systems for electronic components, and especially for a cooling system for us in personal computer systems (PCs) according to the attached independent claims 1, and variations of embodiments as claimed in the dependent claims 2 to 23.

Personal computers are standard equipment in almost every home and office around the world. Business transactions, financial transactions, purchasing of tickets, goods etc. has also almost become the only available purchasing channel. For example, some airplane companies offer tickets only via WEB sites and by issuing only electronic tickets. Our daily life and many tasks are now based on computers and networking. This trend requires that consumers possess computers with sufficient computing power that has few operational problems, and that is online most of the time. One key factor to insure that the electronics of the PC will operate error free in the long run is that the computer system is cooled in a proper manner. Modern Central Processing Units (CPUs) dissipates substantial amounts of heat that must be transported away from the PC cabinet. The traditional method comprises using air cooling with fans. The fans can be part of the cabinet and/or be attached directly on top of the CPU chip, for example. These ventilator arrangements are usually controlled by thermostats such that the fans are working only when it is necessary to lower the temperature of the PC assembly. However, such fans are not soundless providing a relatively noisy environment in a house or workplace. As known to a person skilled in the art, the cooling effect of a fan assembly is directly proportional to the capacity of the fan, i.e. how much air the fan can blow per time unit. It is also known to a person skilled in the art that highly effective CPU units dissipate more heat the faster the processor is. Therefore it is a common experience that the noise level from a PC assembly usually is quit high and is increasing whenever a new faster computer system is installed. This is a disturbing element in any home or office space. Further, when high capacity fans are used, dust and other pollutant are easily trapped inside the PC cabinet which in the long term can be a risk for the PC itself, and which can cause overheating of the PC and in some extreme cases causing fire to break out.

In prior art there exists many proposals for solving the dust problem associated with fan cooling systems by instead circulating a cooling agent like cold water through heat exchangers in thermal contact with electronic components on a circuit board, for example a mother board of a PC system. However, condense and leakage has proven to be a recurrent problem with such solutions, Further, the cooling or heat exchange outside the PC cabinet of the heat transported away from inside of the PC cabinet by the cooling agent usually involves a fan assembly outside the PC.

The patent application WO 2005/011349 A2 discloses a system comprising a cooling device in thermal contact with a single electronic component or a group of components on a printed circuit board. The cooling device is part of a coolant circuit leading dissipated heat away from the component to the outside environment of the electronic assembly. The cooling of the coolant takes place in a primary and a secondary cooler on the outside of the electronic assembly comprising apeltier cooler, a fan assembly and/or a cooling surface. The cooling capacity of the system can be increased by connecting the outside cooling assembly in a serial manner.

The Japanese patent application JP2000000042315 disclose a cooling system comprising peltier elements that can be mounted directly on a printed circuit above integrated circuit components such that the cold side of the peltier element is in thermal contact with the top surfaces of the integrated components, while the hot side of the peltier element is connected to a pipe system transporting heat outside the electronic assembly. The different peltier elements are electrically supplied directly from conductors on the printed circuit board.

Cooling systems not using fans as such is known in prior art. However, a cooling system should also be simple to manufacture, easy to install in a PC, also after the PC itself has been assembled (which is the situation if the user wants to change the cooling system in his/hers PC from fans to a fluid based system, for example). Further, the system should be flexible such that when new components (for example, an additional number cruncher circuit chip is installed on a mother board of a computer system), or an additional memory section (card) is installed in a computer system, or similar additions, it is easy to connect further cooling devices in thermal contact with the additional components.

According to an aspect of the present invention, such a flexible cooling system may be achieved by providing a solution comprising a star coupling (or parallel arrangement) of distribution conduits distributing a cooling agent from a common distribution point connected to individual cooling devices in thermal contact with at least one electronic component. According to an example of embodiment of the present invention, a cooling system comprises a reservoir, wherein at least one peltier element is connected on an outside wall of the reservoir with its cool surface while the warm side is facing the outside environment of the electronic assembly, for example a PC housing or cabinet. A pumping device is connected to the reservoir pumping and filling a distribution element with a cooling agent, such as an inert fluid or water etc., with a slight excess pressure. On an outwardly facing surface of the distribution element there are arranged a plurality of sealable taps wherein distribution conduits can be attached in one end while the other end of the distribution conduit is attached to a cooling device that is in thermal contact with an electronic component. According to yet another example of embodiment of the present invention, the distribution conduit comprises two tubes, one for the supply of cooling agent from the distribution element to the electronic component while the other tube transports the cooling agent back to the reservoir. According to yet another aspect of the present invention, the cooling device is manufactured as one unit comprising the distribution conduit with predefined lengths. This facilitates the installation of a cooling device while at the same time improving the non leakage quality of the cooling device.

According to yet another example of embodiment of the present invention, a non return valve may be installed between the pumping device and the distribution element insuring that a pressure build up will not influence the cooling agent in the connected reservoir. In another example of embodiment, the reservoir comprises an air bleed-off valve.

According to yet another example of embodiment of the present invention, a pressure sensing transducer is connected between the pumping device and the distribution element providing a feedback signal to an electronic controller controlling the pumping device. In yet another example of embodiment, a temperature sensor is also used as a feedback signal that is sensing the temperature in a cooling device.

Figure 1 illustrates an example of embodiment of the present invention.

Figure 2 illustrates another example of embodiment of the present invention.

Figure 3 illustrates another example of embodiment of the present invention.

Figure 4 illustrates an example of cooling device according to the present invention. Figure 5 illustrates an example of arranging a cooling system in a PC cabinet according to the present invention.

5 Figure 6 illustrates an example of embodiment of a reservoir according to the present invention.

Figure 7 illustrates an example of a cooling device according to the present invention.

io Figure 8 illustrates another example of a cooling device according to the present invention.

Figure 9 illustrates an example of distribution element according to the present invention.

I₅

Figure 1 illustrates an example of embodiment of the present invention. A reservoir 10 comprising the cooling agent is connected to a pumping device 11 that moves the cooling agent from the reservoir 10 to a distribution element 12. On an outwardly facing surface of the distribution element 12 a plurality of sealable taps 14 are arranged. When

20 the sealing is removed from a tap a distributing conduit (not shown) can be connected to the tap. The other end of the distribution conduit is connected to a cooling device, for example the device illustrated in figure 4. When the cooling agent is moved through the distribution conduit a collecting conduit (not shown) transport the cooling agent back to a collecting point or element 13 via one of a plurality of sealable and receiving taps 15.

25 The cooling agent is then moved to the reservoir 10 via a return conduit 18.

The pumping device 11 provides a slight excess pressure in the distribution element 12 which ensures that the cooling agent is circulated in the system. In an example of embodiment of the present invention, the distribution conduit supplying the cooling 30 agent to an electronic component from the distribution element 12 is provided with a higher flow capacity (larger diameter of the conduit) than the returning conduit returning the cooling agent back to the collecting element 13. This arrangement insures that the cooling agent will fill a cavity in the cooling device entirely. 5 Figure 2 illustrates another example of embodiment of the present invention, wherein a non return valve 16 is arranged between the pumping device 11 and the distribution element 12. This valve insures that no pressure build up is possible in the reservoir 10. This is preferable to insure that the cooling agent is distributed properly in the system.

In another example of embodiment of the present invention, a valve (not shown) is located between the reservoir 10 and the pumping device 11. When the valve is closed it is possible to use the pumping device 11 to empty the distribution element 12, distribution conduits, collecting conduits etc., which is necessary when maintaining the system, for example when an additional cooling device is to be connected to the distribution element 12.

Another example of embodiment of the present invention comprises an air bleed-off valve on the reservoir 10. This simplifies initial filling of a cooling agent, start of the system after a stop of the system etc., as known to a person skilled in the art.

Figure 3 illustrates yet another example of embodiment wherein an electronic controller controls the pumping device 11. A transducer can be associated with the valve 16 providing a feed back signal to the controller. The transducer can be a pressure transducer measuring the pressure in the distribution element 12, which provides a means for the controller to maintain a substantial constant pressure in the distribution element 12. The transducer can also be a temperature sensor providing a means for maintaining a substantial constant temperature of the cooling agent by increasing the flow of cooling agent through the system, as known to a person skilled in the art.

Figure 4 illustrates an example of embodiment of a cooling device 20 according to the present invention. A cavity inside the cooling device 20 is filled with a cooling agent distributed and supplied via a distribution conduit 21. Inside the cavity of the cooling device 20 it is arranged a partitioning wall 22 originating from the inlet side of the distribution conduit 21 ending inside the cavity without obstructing circulation of the cooling agent through the cavity of the cooling device back to the return conduit 23 which is arranged on the other side of the partitioning wall 22. This arrangement insures that there is no shunt of the cooling agent flowing between the inlet and outlet of the cooling agent to and from the cooling device 20.

In another example of embodiment of the cooling device illustrated in figure 4, the partitioning wall 22 comprises a temperature sensor measuring the temperature in the cooling agent inside the cavity of the cooling device 20. The electronic signal wires can be embedded as part of the conduits 21, 23 for the cooling agent to and from the cooling device 20. In stead of a temperature sensor, a pressure transducer may be used alone or together with the temperature sensor.

In an example of embodiment of the conduits 21, 23 according to the present invention, the respective conduits 21, 23 can be manufactures as two separate parallel tubes in a common conduit. Such conduits can be manufactured as an integral part of the cooling device 20 as well. This insures that no leakage can occur in a joint between the cooling device 20 and the conduit. For example, the cooling device 20 can be manufactured out of a plastic with low thermal resistance. Then it is easy to for example to weld the conduit to the cooling device. If the cooling device is manufactured out of metal, a plastic coating covering the top and side faces, but not the bottom face of the cooling device can be used to attach the conduits, for example by welding, to the cooling device.

hi an example of embodiment of the cooling device according to the present invention the top surface and side surfaces, but not the bottom surface of the cooling device 20 comprises an insulating layer insuring that the cooling effect of the cooling device is more effective while at the same time preventing dew to be created on the outside of the cooling device. This insulating layer may also be used to attach conduits to the cooling device, for example by welding.

In yet another example of embodiment of the present invention, the cooling device 20 as depicted in figure 4 may comprise separate inlet and outlet for the conduits 21 and 23, respectively, for example arranged on opposing sides of the cooling device 20. The partitioning wall 22 may then be omitted.

According to an aspect of the present invention, the cooling device 20 may be manufactured in different sizes adapted to the size of individual integrated circuits. The thermal contact between the cooling device 20 and the integrated circuit may be established by gluing the cooling device to the integrated circuit with glue having low thermal resistance, as known to a person skilled in the art.

According to another aspect of the present invention, if the cooling capacity of one cooling device 20 is too small for a given integrated circuit, an increased cooling capacity may be achieved by simply using non thermal insulated cooling devices stacked on top of each other. A thermal insulating cover may then be applied on the stack of cooling devices. According to yet another aspect of the present invention, cooling devices may be manufactured comprising conduits comprising different standard lengths of the conduits, respectively.

Figure 5 illustrates an example of arranging a cooling system according to the present invention inside a PC cabinet. The electronic motherboard 31 is arranged in one top end of the cabinet while the reservoir 10 and pumping device 11 is arranged in an assembly 32 on the outside lower back side of the PC cabinet. The distribution element 12 is arranged above the mother board 31 allowing distribution conduits 21 to be distributed to different cooling devices 20 on top of integrated circuits on the mother board 31. Collecting element 13 collects the cooling agent flowing through the cooling devices 20 via collecting conduits 23. Conduit 34 distributes/collects cooling agent to from the reservoir 10 and pumping device 11 arrangement 32, respectively.

As can easily be understood, the main benefits of this cooling arrangement according to the present invention, id the star connection of cooling devices achieved by using the distribution element 12 and collecting element 13. First of all, the temperature of the cooling agent is the same temperature for all cooling devices. This is a direct technical effect of the star connection. Further, This insures that all electronic circuits that are to be cooled is cooled with a sufficient capacity, either by a single cooling device, a stacking of cooling devices, or via similar arrangements. Further, the arrangement depicted in figure 5 combines effects form closed cooling systems and open cooling systems. When the distribution conduit 21 has larger flow capacity than the collecting conduit 23, cavities and conduits are all filled with maximum amount of cooling agent insuring maximum cooling capacity of the system. This usually only possible with closed systems under high pressure conditions, as known to a person skilled in the art. When the pumping device 11 is stopped, for example when the PC is turned off or an additional cooling device is to be installed, the cooling agent will flow due to gravity out of the distribution element 12 back to the reservoir 10 in the arrangement 32. This effect is usually only possible in an open system, as known to a person skilled in the art.

Figure 6 illustrates an example of embodiment of the reservoir 10 according to the present invention, Inlet and outlets 40, 43, respectively, provides taps for distributing and collecting the cooling agent in a cooling system. Peltier elements can be attached to recess 41 wherein the cold side of the peltier element is facing towards the reservoir 10 while the warm side is facing outward. Recess 42 can be used to house wires supplying current to the peltier elements, hi another example of embodiment of the present invention, an insulating layer can be attached around the perimeter of each peltier element in the recesses 41.

Figure 7 and 9 illustrates examples of other types of cooling devices inside the scope of the present invention. Figure 7 illustrates how a memory card can be encapsulated with a cooling device. Figure 8 illustrates how an additional circuit board can be encapsulated by a cooling device.

Figure 9 illustrates an example of embodiment of a distribution element 51 comprising a collecting element 50 attached to the same side of the collecting element distributing taps 53 are arranged. The collecting taps 51 are arranged on locations relative to the distributing taps 53 such that when a conduit comprising two tubes 21, 23 respectively is used, they are easily and directly connectable to the respective taps of the distributing element 52 and the collecting element 50. The collecting element 50 is in fluid communication with the reservoir 10 through a separate conduit.

Li another example of embodiment of the present invention, when a cooling device 20 comprises a temperature sensing devise, for example, the wires connected to the temperature sensor maybe part of the combined conduit comprising tubes 21, 23 by embedding the wires inside the common conduit between the tubes 21, 23. In the example of distributing element as depicted in figure 9, electric contacts for such wires can be arranged between the respective taps 51, 53 (not shown).

According to an aspect of the present invention, the cooling system may be used not only in connection with PC system. Any type of electronic assembly that needs to be cooled to operate properly is inside the scope of the present invention.

Claims

C l a i m s :

1.

Cooling system for use in a Personal Computing (PC) system, comprising:

a fluid reservoir (10) in thermal contact with a cooling arrangement and a pumping device (11) in fluid communication with at least one cooling device (20) in thermal contact with at least one electronic component in the PC system, wherein the pumping device (11) supplies a cooling agent in the reservoir (10) to a distributing element (12) comprising a plurality of sealable distributing taps (14, 53) for distributing the cooling agent to the at least one cooling device (20) in parallel via conduits attached to the distributing taps (14,53), wherein the cooling device (20) is arranged with a cavity receiving the cooling agent via a distributing conduit (21), wherein the cooling agent is removed from the cavity via a collecting conduit (23), and wherein the distributing conduit (21) and collecting conduit (23) is manufactured as an integral part of the cooling device (20).

2.

Cooling system according to claim 1, wherein the distributing conduit (21) and collecting conduit (23), respectively, is manufactured in different standard lengths.

3.

Cooling system according to claim 2, wherein the distributing conduit (21) and collecting conduit (23) is fitted with a fastening element adapted to attach the distributing conduits (21) and collecting conduits (23) on respective taps on the distributing element (11) and collecting element (13).

4.

Cooling system according to claim 1, wherein the distributing conduit (21) and collecting conduit (23) is manufactured as two distinct parallel tubes in a common conduit.

5.

Cooling system according to claim 1, wherein the cavity of the cooling device (20) comprises a partitioning wall 22 originating from the centre of the common conduit of the cooling device (20) and extending inside the cavity without stopping the flow of the cooling agent in the cavity.

6.

Cooling system according to claim 5, wherein the partitioning wall (22) comprises a temperature sensor.

7.

Cooling system according to claim 5, wherein the partitioning wall (22) comprises a pressure transducer.

8. Cooling system according to claim 6 or 7, wherein electrical wires for communicating power and signals to/from the temperature sensor and/or pressure sensor is embedded into the common conduit for the cooling agent.

9.

Cooling system according to claim 1, wherein the cooling device is manufactured in sizes adapted to different sizes of different electronic components.

10.

Cooling system according to claim 1, wherein the cooling device (20) is attached to a top surface of an integrated circuit by gluing the cooling device (20) to the top surface of the electronic component with glue having low thermal resistance.

11.

Cooling system according to claim 1, wherein a further cooling device (20) is glued on top of a first cooling device (20) attached to the top surface of the electronic component.

12.

Cooling system according to claim 1, wherein an insulating layer is applied on all surfaces of the cooling device except the side of the cooling device (20) to be arranged in thermal contact with an electronic component.

13.

Cooling system according to claim 1, wherein the cooling arrangement in thermal contact with the reservoir (10) comprises at least one peltier element wherein the cold side of the at least one peltier element is facing towards one side of the reservoir (10) while the other side of the peltier element is facing towards the external environment of the PC system.

14.

Cooling system according to claim 1, wherein an insulating layer is arranged around the perimeter of the at least one peltier element.

s 15.

Cooling system according to claim 1, wherein an air bleed-off valve is arranged on an outwardly facing side of the reservoir (10).

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