JP2013187251A - Cooling system and method of electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling system which efficiently cools an entire electronic apparatus using a liquid refrigerant and easily reuses waste heat of the electronic apparatus.SOLUTION: An electronic apparatus 1 includes multiple heating elements 3 on a substrate 2. A system 11 cooling the electronic apparatus 1 includes: a package member 5 enclosing the entire substrate 2 including the elements 3; a container 12 in which a liquid refrigerant C is accumulated; a holder 16 holding the package member 5 in the container 12 with the package member 5 immersed in the liquid refrigerant; and a refrigerant circulation mechanism forming refrigerant flow F in the container 12. The refrigerant circulation mechanism includes a refrigerant circulation passage for taking out the relatively high temperature liquid refrigerant from an outlet 14 of the container 12 and returning the relatively low temperature liquid refrigerant to an inlet 13 of the container 12. An electric generator, generating electric power using the liquid refrigerant taken out from the container 12, is provided on the refrigerant circulation passage.

Description

  The present invention relates to a system and method for cooling an electronic device having a plurality of elements mounted on a substrate.

  Conventionally, a system that circulates a liquid refrigerant inside an electronic device and cools elements such as a CPU and a memory on a substrate is known. However, since this type of system partially cools a specific element, in the case of an electronic device in which a large number of heat-generating elements are densely arranged on a substrate, liquid cooling and air cooling are performed to cool the entire substrate. There is a problem that it is necessary to use them together, and power consumption increases when used in a data center or the like.

  Therefore, conventionally, a system for cooling the heat-generating element by directly immersing it in a liquid refrigerant has been proposed. For example, in Patent Document 1, liquid refrigerant is supplied to a low heat generation density module unit and a high heat generation density module unit by a circulation pump, and the low heat generation density element and the high heat generation density element are directly immersed in the liquid refrigerant. A cooling system for controlling the pressure and saturation temperature of each module unit is described.

JP-A-5-160310

  However, according to the conventional cooling system, since the exothermic element is directly immersed in the liquid refrigerant, the flux component and the like eluted from the element and the substrate are ionized, and the insulation performance of the liquid refrigerant gradually decreases. In addition, the altered liquid refrigerant is difficult to reuse, and the exhaust heat of the electronic devices contained in the liquid refrigerant cannot be reused, especially in a data center that uses a large amount of refrigerant, which is wasteful and unsuitable. It was.

  The objective of this invention is providing the cooling system which can cool the whole electronic device efficiently using a liquid refrigerant, and can reuse the waste heat of an electronic device easily.

In order to solve the above problems, the present invention provides the following cooling system and cooling method.
(1) A system for cooling an electronic device having a plurality of elements mounted on a substrate, the package member enclosing the entire substrate including the elements, a container for storing liquid refrigerant, and the package member as liquid refrigerant A cooling system comprising: a holder that is held in a container while being immersed therein; and a refrigerant distribution mechanism that forms a flow of liquid refrigerant inside the container.

(2) A cooling system, wherein the refrigerant circulation mechanism includes a refrigerant circulation line that takes out a relatively high-temperature liquid refrigerant from the container and returns the relatively low-temperature liquid refrigerant to the container.

(3) A cooling system characterized in that a generator for generating electric power using a liquid refrigerant taken out from a container is provided on a refrigerant circulation line.

(4) A cooling system in which a tank for generating hot water using a liquid refrigerant taken out from a container is provided on a refrigerant circulation line.

(5) The cooling system, wherein the package member includes a metal case in which the electronic device can be removed.

(6) A cooling system comprising an insulating sheet interposed between the inner surface of the metal case and the element.

(7) A cooling system characterized in that heat radiation fins are provided on the outer surface of the metal case.

(8) The cooling system, wherein the package member includes an insulating cover that is in close contact with a substrate and an element of the electronic device.

(9) The cooling system, wherein the insulating cover includes a resin layer in contact with the substrate and the element, and a metal layer in contact with the liquid refrigerant.

(10) An electronic device having a plurality of elements mounted on a substrate is prepared, the entire substrate including the elements is encapsulated in a package member, the package member is immersed in a liquid refrigerant inside the container, and the heat generated by the element is packaged. A method for cooling an electronic device, comprising: transferring a liquid refrigerant to a liquid refrigerant through a member; allowing the liquid refrigerant to flow inside the container;

(11) A method for cooling an electronic device, wherein a fluorocarbon coolant having a boiling point of 100 ° C. or less is used as the liquid refrigerant.

(12) A method for cooling an electronic device, characterized in that the liquid refrigerant includes droplets sprayed inside the container.

  According to the cooling system and the cooling method of the present invention, since the entire substrate including the element is immersed in the liquid refrigerant in a state of being encapsulated by the package member, there is a possibility that the liquid refrigerant may be altered by the eluted component from the element or the substrate. Thus, the electronic device can be cooled safely and efficiently, and the exhaust heat of the electronic device can be easily reused.

It is a perspective view of an electronic device showing one embodiment of the present invention. It is sectional drawing which shows the cooling system of the electronic device of FIG. It is sectional drawing which shows the example of a change of a package member. It is sectional drawing which shows the example of a change of a container. It is sectional drawing of the container in which the some electronic device was hold | maintained. It is the schematic which shows the server cooling system for data centers.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. An electronic device 1 shown in FIGS. 1 and 2 includes a plurality of elements 3 and an electronic circuit (not shown) on a substrate 2. The element 3 includes a heat generating electronic device such as a CPU, a memory, a transistor, and a register, and is mounted on the substrate 2 at a predetermined position in the electronic circuit. A connector 4 is provided at the peripheral edge of the substrate 2, and the entire substrate 2 including the element 3 is encapsulated by a package member 5 except for the connector 4.

  A package member 5 shown in FIGS. 1 and 2 includes a metal case 6 composed of two aluminum plates 6a and 6b, and a substrate 2 is accommodated inside the metal case 6 so as to be removable. The two plates 6 a and 6 b are joined via the waterproof packing 7, and the periphery is fastened so as to be separable by a plurality of fasteners 8. Between the inner surfaces of the plates 6a and 6b and the element 3 and the substrate 2, an insulating sheet 9 made of graphite having high heat conductivity is interposed. On the outer surfaces of the plates 6a and 6b, heat radiating fins 10 for releasing heat generated from the element 3 to the outside of the package member 5 are formed.

  The cooling system 11 of the electronic device 1 includes a container 12 that stores the liquid refrigerant C. On the upper surface of the container 12, an inlet 13 and an outlet 14 and an insertion port 15 for the liquid refrigerant C are provided. A holder 16 for suspending the package member 5 is inserted into the insertion port 15. The holder 16 is formed of an elastic material such as rubber, and is configured to hold the water tightness of the insertion port 15 and to hold the package member 5 in the container 12 while being immersed in the liquid refrigerant C.

  The package member 5 shown in FIG. 3 includes an insulating cover 18 that is in close contact with the substrate 2 and the element 3. The insulating cover 18 includes a resin layer 18a that is in contact with the substrate 2 and the element 3 while maintaining electrical insulation, and a metal layer 18b that is in contact with the liquid refrigerant C and has high heat conductivity. The resin layer 18a ensures electrical insulation. Thus, the watertightness of the package member 5 is ensured while being in close contact with the substrate 2 and the element 3.

  Moreover, as shown in FIG. 4, the container 12 may be formed in a bag shape with a resin sheet or film, and the package member 5 shown in FIG. 2 or 3 may be accommodated in the flexible bag. FIG. 5 shows a large container 12 suitable for cooling a large number of servers 1 (electronic devices) in a data center or the like. The container 12 is formed with a volume capable of storing a plurality of package members 5 therein and storing liquid refrigerant C having a capacity corresponding to the number of package members 5. The upper surface of the container 12 is covered with a lid member 23, and a plurality of holders 16 for holding the package member 5 are attached to the lid member 23.

  As shown in FIG. 6, a rack 25 installed in the data center stores a plurality of containers 12 that store the server 1, and the flow F of the liquid refrigerant C inside each container 12 (FIGS. 2 and 3). The refrigerant circulation mechanism 26 forming the reference) is connected. The refrigerant circulation mechanism 26 is equipped with a refrigerant circulation pipe 27 extending between the inlet 13 and the outlet 14 of the container 12, and a relatively high-temperature liquid refrigerant C is taken out from the container 12 through this pipe 27. The low-temperature liquid refrigerant C is returned to the container 12.

  On the refrigerant circulation line 27, the solar heater 28 that heats the liquid refrigerant C taken out of the container 12 by solar heat, the generator 29 that generates electric power using the heated liquid refrigerant C, and the generator 29 are passed. The tank 30 that generates hot water using the residual heat of the liquid refrigerant C, the pump 31 that pumps the liquid refrigerant C using a part of the electric power generated by the generator 29, and the surplus power generated by the generator 29 are stored. A storage battery 32 is provided.

  As the liquid refrigerant C, a fluorocarbon coolant having a boiling point of 100 ° C. or less, for example, trade names “Novec 7300 (boiling point 98 ° C.), Novec 7200 (boiling point 76 ° C.), Novec 7100 (boiling point 61 ° C.)” (both Sumitomo 3M) Can be preferably used. Since the low-boiling fluorocarbon coolant easily evaporates due to the heat generated by the element 3, the propeller and turbine of the generator 29 can be efficiently rotated by the steam flow taken out from the container 12, and the amount of power generation can be increased. The solar heater 28 is provided on the bypass line 34, and the bypass line 34 is connected to the refrigerant circulation line 27 via the valve 33. Then, by switching the flow of the refrigerant C to the bypass line 34 side, a large amount of steam flow can be supplied from the solar heater 28 by the generator 29.

  Next, the cooling method of the electronic apparatus 1 in the cooling system 11 having the above configuration will be described. First, as shown in FIG. 1, a substrate is encapsulated with a package member 5, and a required number of electronic devices 1 are prepared. Next, as shown in FIGS. 2 to 5, the package member 5 is immersed in the liquid refrigerant C and held in the container 12 by the holder 16. In this state, the heat generated by the element 3 is transmitted to the liquid refrigerant C through the metal case 6 (see FIG. 2) or the insulating cover 18 (see FIG. 3) of the package member 5.

  Subsequently, as shown in FIG. 6, the liquid refrigerant C is pumped to the container 12 by the pump 31 of the refrigerant circulation mechanism 26, and flows from the inlet 13 toward the outlet 14. Then, the high-temperature liquid refrigerant C deprived of the heat generated by the element 3 is taken out of the container 12, further heated by the solar heater 28 as necessary, electric power is generated by the generator 29, and part of the electric power is supplied to the pump 31. After supplying the surplus power in the storage battery 32 and generating the hot water in the tank 30 using the liquid refrigerant C that has passed through the generator 29, the liquid refrigerant C whose temperature has decreased is recirculated to the container 12 by the pump 31.

  According to the cooling system and the cooling method of this embodiment, since the entire substrate 2 including the element 3 is immersed in the liquid refrigerant C in a state of being encapsulated by the package member 5, it is eluted from the electronic circuit of the element 3 and the substrate 2. It is possible to prevent alteration of the liquid refrigerant C due to the flux component and the like. Therefore, in particular, there are advantages that a large number of servers 1 can be cooled safely and efficiently in the data center, and the exhaust heat of the servers 1 can be effectively reused.

  The present invention is not limited to the above embodiment. For example, a nozzle that sprays liquid refrigerant in the form of droplets (mist) in the container 12 is provided, and high-temperature droplets are placed outside the container 12. It is also possible to implement by appropriately changing the configuration of each part without departing from the gist of the present invention, such as taking out and driving the turbine of the generator 29.

DESCRIPTION OF SYMBOLS 1 Electronic device 2 Board | substrate 3 Element 5 Package member 6 Metal case 9 Insulation sheet 10 Radiation fin 11 Cooling system 12 Container 16 Holder 18 Insulation cover 26 Refrigerant circulation mechanism 27 Refrigerant circulation line 29 Generator 30 Tank C Liquid refrigerant F Refrigerant flow

Claims (12)

  A system for cooling an electronic device having a plurality of elements mounted on a substrate, the package member enclosing the entire substrate including the elements, a container for storing liquid refrigerant, and the package member in liquid refrigerant A cooling system comprising: a holder that is held in a container while being immersed in the container; and a refrigerant circulation mechanism that forms a flow of liquid refrigerant inside the container.   The cooling system according to claim 1, wherein the refrigerant circulation mechanism includes a refrigerant circulation pipe that takes out a relatively high-temperature liquid refrigerant from the container and returns the relatively low-temperature liquid refrigerant to the container.   The cooling system of Claim 2 which provided the generator which produces | generates electric power using the liquid refrigerant taken out from the container on the said refrigerant | coolant circulation conduit.   The cooling system according to claim 2 or 3, wherein a tank for generating hot water using the liquid refrigerant taken out from the container is provided on the refrigerant circulation pipe.   The cooling system according to claim 1, wherein the package member includes a metal case that accommodates the substrate in a removable manner.   The cooling system according to claim 5, wherein an insulating sheet is interposed between the inner surface of the metal case and the element.   The cooling system according to claim 5 or 6, wherein heat radiation fins are provided on an outer surface of the metal case.   The cooling system according to claim 1, wherein the package member includes an insulating cover that is in close contact with the substrate and the element.   The cooling system according to claim 8, wherein the insulating cover includes a resin layer that contacts the substrate and the element, and a metal layer that contacts the liquid refrigerant.   An electronic device having a plurality of elements mounted on a substrate is prepared, the entire substrate including the elements is encapsulated in a package member, the package member is immersed in a liquid refrigerant inside the container, and the heat generated by the elements is packaged. A method for cooling an electronic device, comprising: transferring to a liquid refrigerant through a member, allowing the liquid refrigerant to flow inside the container, and then taking the liquid refrigerant out of the container.   The method for cooling an electronic device according to claim 11, wherein a fluorocarbon coolant having a boiling point of 100 ° C. or less is used as the liquid refrigerant.   12. The method for cooling an electronic device according to claim 10, wherein the liquid refrigerant includes droplets sprayed inside the container.

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