JP2006005039A - Cooling system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To considerably enhance efficiency by combinedly using a high heat conductive metal and ceramic for a heat transmission part of a cooling system using a refrigerant. <P>SOLUTION: In the cooling system, heat generated from a heat generating component is moved to the refrigerant, and the refrigerant is circulated by a pump, thereby radiating heat from a heat radiation part to the atmosphere. By this constitution, high heat conductive fine particles 7 are mixed with the refrigerant. Alternatively, one end of a bundle of high heat conductive lines 8 is fixed to a part of the inside of a refrigerant accommodating metal case which comes into direct contact with the heat generating component, to be arranged in a tube 3 for transferring the refrigerant, and the other end thereof is fixed to a part of a heat radiation part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cooling system in which liquid is circulated by a pump to move heat and mainly perform cooling.

  In recent years, the amount of heat generated has increased as the processing speed of the CPU has increased. A conventional system in which a heat sink is attached and cooled by a fan is approaching its limit. For this reason, a cooling system that efficiently cools the CPU and other electronic components is desired. As a cooling method corresponding to this, a refrigerant-type cooling system that circulates and cools the refrigerant has been proposed (for example, see Patent Document 1). ). Hereinafter, a conventional cooling system that circulates and cools such a refrigerant will be described. As this conventional cooling system, for example, the one shown in FIG. 3 is known. FIG. 3 is a block diagram of a conventional cooling system. In FIG. 3, reference numeral 100 denotes a housing, 101 denotes a CPU, 102 denotes a substrate on which the CPU 101 is mounted, 103 denotes a cooler that cools the CPU 101 by exchanging heat between the CPU 101 and the refrigerant, and 104 removes heat from the refrigerant. A heat radiator, 105 is a pump for circulating the refrigerant, 106 is a pipe for connecting them, and 107 is a fan for air-cooling the heat radiator 104.

  The operation of the conventional first cooling system will be described. The refrigerant discharged from the pump 105 is sent to the cooler 103 through the pipe 106. Here, the heat from the CPU 101 is removed and the temperature rises and is sent to the radiator 104. This radiator 104 is forcibly air-cooled by a fan 107 and its temperature drops, and then returns to the pump 105 and repeats this. In this way, the CPU 101 is cooled by circulating the refrigerant.

Next, as a conventional second cooling system as shown in FIG. 2 (see, for example, Patent Document 2), the efficiency of the first cooling system of the CPU is greatly improved. The operation of the conventional second cooling system will be described with reference to FIG. 2 and FIG. 1 because the relationship between the heat receiving portion and the heat radiating portion is the same as that of the present invention. FIG. 2 is an exploded perspective view of the pump of the present invention as seen from the casing side. In the second cooling system, the contact heat exchange type pump is brought into contact with the CPU and heat is taken from the CPU 4 by the heat exchange action of the internal refrigerant. The cooling system for radiating heat from the heat radiating section, wherein the pump casing of the contact heat exchange type pump is made of a material having high thermal conductivity, and the pump casing has a heat receiving surface on the side surface along the internal pump chamber. The heat receiving surface is formed in a shape complementary to the three-dimensional shape of the upper surface of the CPU at the contact position. When a controlled current is applied to the pump stator 6, the rotor (impeller) 5 starts rotating. The impeller 11 integrated with the rotor 6 gives kinetic energy to the refrigerant flowing from the suction port 15 and sends it to the discharge port 16. . At this time, a turbulent flow is generated in a region surrounded by the pump casing 9 and the casing cover 10, and heat of the pump casing 9 that has reached a high temperature is given to the refrigerant. The refrigerant whose temperature is increased by removing heat from the CPU is sent to the radiator 2 through the pipe (tube) 3, cooled by the radiator 2, and after the temperature has dropped, the refrigerant again passes through the pipe (tube) 3 to contact heat. The CPU 4 was cooled by returning to the exchange pump and repeating this.
JP-A-5-264139 JP 2004-47921 A

However, the conventional first cooling system has many components such as a cooler 103 that cools the CPU 101 by exchanging heat between the CPU 101 and the refrigerant, a radiator 104 that removes heat from the refrigerant, and a pump 105 that circulates the refrigerant. There was a problem that miniaturization was difficult and cost was high. The conventional second cooling system is a system that can be stored compactly and has excellent heat exchange characteristics, but has a limit in absorbing heat generated by the CPU 4.

  Therefore, an object of the present invention is to provide a cooling system that can greatly improve the cooling effect and can cope with a reduction in size and thickness.

  In order to solve this problem, the cooling system of the present invention is characterized in that highly heat conductive fine particles such as gold, silver, copper, aluminum, diamond, silicon carbide, and aluminum nitride are mixed in a refrigerant that transfers heat. To do.

  Thereby, it is possible to realize a cooling device that can improve the cooling efficiency while having a simple structure and low cost.

  Further, the cooling system of the present invention has one end fixed to a part of the inside of the refrigerant housing metal case in which a bundle of highly heat conductive wires is in direct contact with the heat generating component, and is disposed in a tube for transferring the refrigerant. One end is fixed to a part of the heat radiating portion.

  Thereby, it is possible to realize a cooling device that can improve the cooling efficiency while having a simple structure and low cost.

  As described above, according to the present invention, the movement of heat from the heat receiving portion to the heat radiating portion is not limited to refrigerant (water) having a low thermal conductivity, but also fine particles of high heat conductive metal or high heat conductive ceramics or high heat. By replacing a bundle of conductive metal wires or carbon fiber wires, a more efficient cooling system is provided.

  The invention according to claim 1 of the present invention is a heat receiving part that transfers heat generated from a heat-generating component to a refrigerant, and a cooling system that radiates heat from the heat radiating part to the atmosphere by circulating the refrigerant with a pump. Since it is a cooling system characterized by mixing high heat conductive fine particles, the efficiency of heat transfer by the refrigerant can be improved, and the cooling efficiency can be improved without complicating the system.

  The invention according to claim 2 of the present invention is a cooling system in which heat generated from a heat generating component is transferred to a refrigerant, and the refrigerant is radiated from the heat radiating part to the atmosphere by circulating the refrigerant with a pump. Since the cooling system is characterized in that one end is fixed inside the case of the heat receiving part and the other end is fixed inside the case of the heat radiating part, the heat transfer efficiency can be achieved without increasing the refrigerant transfer speed. And cooling efficiency can be improved.

  The invention according to claim 3 of the present invention is characterized in that the high thermal conductive fine particles mixed in the refrigerant are composed of one or more of silver, copper, aluminum, diamond, silicon carbide, and aluminum nitride. Since it is the cooling system of 1, it is possible to select the optimum type, size and filling amount according to the performance of the pump.

  The invention according to claim 4 of the present invention is characterized in that the material of the bundle of wires arranged in the tube is composed of one or more of gold, silver, copper, aluminum, and carbon fiber. Therefore, the optimum combination can be obtained according to the complexity of the space to be arranged and the rigidity of the tube.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. In these drawings, the same members are denoted by the same reference numerals, and redundant description is omitted.

(Embodiment 1)
1A is a diagram showing an outline of a cooling system in Embodiment 1 of the present invention, FIG. 1B is a diagram showing a cross-sectional perspective view of a portion in Embodiment 1 of the present invention, and FIG. 1C is an implementation of the present invention. It is a figure which shows the cross-sectional perspective of the A part in another application example of the form 1. In FIG. 1, 1 is a heat receiving part for transferring heat from the CPU 4 to the refrigerant, 2 is a heat radiating part for discharging the heat of the heated refrigerant into the air, and 3 is a heat radiating part 2 from the heat receiving part 1 or a heat radiating part 2. A pipe (tube) through which the refrigerant circulates from the heat receiving section 1 to the CPU 4 for releasing heat, 5 a rotor (impeller) of the pump that stirs the refrigerant and promotes circulation of the refrigerant, and 6 is magnetically connected to the rotor 5. , A stator for rotating the rotor 5, 9 is a metal pump casing for sealing the refrigerant and transferring the heat of the CPU to the refrigerant, 12 is a shaft serving as a rotation axis of the rotor 5, 7 is High heat conductive fine particles 8 added to the refrigerant, 8 is a bundle of high heat conductive wires disposed in the pipe. As the refrigerant, those mainly composed of water and added with harmless propylene glycol used for food additives and the like are suitable, and when aluminum or copper is used as a casing material as described later, these are used. It is desirable to add an anticorrosive additive for improving the anticorrosion performance against the above.

  The heat dissipating part 2 needs to remove heat from the refrigerant in a narrow and wide space on the back surface of the display device of the notebook personal computer. Therefore, the heat dissipating part 2 is made of a thin plate material such as copper or aluminum having high heat conductivity and good heat dissipation. It is comprised and the refrigerant path is formed in the inside. Moreover, you may provide the fan for forcing air to the thermal radiation part 2 and cooling. The pipe (tube) 3 is composed of a rubber tube made of a flexible rubber having a low gas permeability, for example, butyl rubber, in order to secure a degree of freedom of the pipe layout. This is to prevent bubbles from entering the tube 3.

Next, the operation of the cooling system in the first embodiment will be described. When electric power is supplied from an external power source, a current controlled by a semiconductor switching circuit provided in the pump flows through the coil of the stator 6 and a rotating magnetic field is generated. When this rotating magnetic field acts on the rotor magnet, the impeller 11 formed integrally with the rotor magnet rotates about the shaft 12. The blades provided in the impeller 11 give kinetic energy to the refrigerant flowing in from the suction port 15, and the kinetic energy increases the pressure of the refrigerant in the casing and discharges it from the discharge port 16. Next, heat transfer will be described. CPU4 which is a heat generating source is being fixed in the state pressed against the casing via the heat conduction grease. Heat generated from the CPU 4 is transmitted to the pump casing 9 through this grease. Since the pump casing 9 is made of a metal having high thermal conductivity, the pump casing 9 is immediately transmitted to the surface in contact with the refrigerant on the opposite side. The material of the pump casing 9 is preferably aluminum (236 W / m · K) or copper (403 W / m · K) having a high thermal conductivity. However, since the surface area of the CPU 4 which is a heat source is a square having a side of 10 mm or 7 mm, how to diffuse the heat becomes a big problem. For this reason, the surface which contacts the refrigerant | coolant of the other side is devised to make a surface area large by providing unevenness or making the surface rough. Next, the heat that has reached the opposite surface (surface that contacts the refrigerant) of the pump casing 9 is transferred to the refrigerant. As the refrigerant, water having the highest thermal conductivity (0.56 W / m · K) is used as the main refrigerant in the liquid. In actual use, in order to prevent destruction of equipment due to freezing, a material such as ethylene glycol or propylene glycol is mixed to lower the freezing point. For this reason, the heat conduction has to be slightly lowered. Liquid (water) has a thermal conductivity nearly 20 times higher than that of gas (air; thermal conductivity = 0.0241 W / m · K), so it is overwhelmingly advantageous compared to air cooling. In comparison, it is less than 1/200. Therefore, metals that are highly heat conductive materials in liquids, among them, gold (319 W / m · K), silver (428 W / m · K), which have high heat conductivity.
), Copper (403 W / m · K), aluminum (236 W / m · K), or inorganic diamond (about 2000 W / m · K), silicon carbide (about 250 W / m · K), aluminum nitride (about By mixing high thermal conductive fine particles 7 such as 250 W / m · K), a part of heat transfer / heat conduction is handled. However, the high thermal conductive fine particles 7 should not be so small as to enter the gap between the pump shaft and the bearing. As the size, a diameter of about 100 μm to about 500 μm is appropriate. Moreover, it should be smaller than the gap between the impeller 11 and the pump casing 9. Further, the high heat conductive fine particles 7 can flow into the heat radiating portion through the tube and exchange heat by contact with the heat radiating plate. As another usage, it is also possible to use metal particles having a large specific gravity as an auxiliary means for transferring heat to the refrigerant by staying in the casing of the heat receiving section and moving around the casing by the rotation of the impeller. . On the other hand, as a means for improving the thermal conductivity of the refrigerant, high thermal conductivity is formed by combining one or a combination of gold, silver, copper, aluminum, and carbon fiber (thermal conductivity of 500 W / m · K or more) in a part of the casing. By fixing the bundle of conductive wires 8 by screwing or welding, etc., arranging the bundle 8 of high thermal conductivity wires in the pipe (tube) 3, and screwing the other to the heat sink or fixing by welding. In addition, the heat of the casing is moved through the refrigerant, and can be directly performed. The bundle of wires should be flexible so that it can be moved freely when opening and closing the display part in the case of a notebook computer, or when attaching the heat receiving part 1 and the radiator 2 as with the pipe (tube) 3. And Also, when it is arranged in the pipe (tube) 3, it is set so as to occupy a volume that does not disturb the flow of the refrigerant. A suitable diameter of one high thermal conductive wire is about 100 μm. It is preferable to use a bundle of about 10 to 50 wires as the bundle 8 of high thermal conductivity wires.

  The cooling system of the present invention is useful for cooling an electronic device using a cooling device that circulates and cools a refrigerant.

(A) The figure which shows the outline | summary of the cooling system in Embodiment 1 of this invention, (b) The figure which shows the cross-sectional perspective view of the part in Embodiment 1 of this invention, (c) It is Embodiment 1 of this invention. The figure which shows the cross-sectional perspective of the part in another application example The exploded perspective view which looked at the pump of the present invention from the casing side Configuration diagram of conventional cooling system

Explanation of symbols

1 Heat Receiving Section 2 Radiator 3 Piping (Tube)
4 CPU
5 Rotor 6 Stator
7 High Thermal Conductive Particles 8 Bundles of High Thermal Conduction Wires 9 Pump Casing 10 Casing Cover 11 Impeller 12 Shaft 13 Partition Ring 14 O-ring 15 Suction Port 16 Discharge Port 17 Screw 100 Case 101 CPU
102 CPU board 103 Cooler 104 Radiator 105 Pump 106 Piping 107 Fan

Claims (4)

A cooling system in which heat generated from a heat generating component is transferred to a refrigerant, and the refrigerant is circulated by a pump to radiate heat from the heat radiating part to the atmosphere. The cooling system is characterized in that high thermal conductive fine particles are mixed in the refrigerant. . In the heat receiving part that moves the heat generated from the heat-generating parts to the refrigerant, and in the cooling system that radiates the heat from the heat radiating part to the atmosphere by circulating the refrigerant with a pump, a bundle of highly heat conductive wires is placed inside the case of the heat receiving part A cooling system characterized in that one end is fixed and the other end is fixed inside the case of the heat radiation part. 2. The cooling system according to claim 1, wherein the high thermal conductive fine particles mixed in the refrigerant are composed of one or more of gold, silver, copper, aluminum, diamond, silicon carbide, and aluminum nitride. The cooling system according to claim 2, wherein the material of the bundle of wires arranged in the tube is made of one or more of gold, silver, copper, aluminum, and carbon fiber.

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