JP2005064092A - Boiling cooler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a boiling cooler in which heat dissipation power is enhanced. <P>SOLUTION: Liquid level in a first refrigerant passage 3 substantially matches the position of a heat absorbing part 2a. Since the majority of absorbed heat can be dissipated in the form of condensation heat while absorbing heat from a central operating unit 2 in the form of evaporation latent heat, sufficient quantity of heat can be dissipated while absorbing heat efficiently from the central operating unit 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boiling cooling device that boils a refrigerant by heat generated by a heating element and absorbs heat from the heating element, and cools an integrated circuit for an electronic computer such as a central processing unit (CPU). Therefore, it is effective when applied to a cooling device.

  As a boiling-type cooling device for cooling a central processing unit (CPU), conventionally, as shown in FIG. 3, a refrigerant is used so that the liquid level is located at a position higher than the heat absorption part 2a where the central processing unit 2 is arranged. Was filling.

  However, if the refrigerant is filled so that the liquid level is positioned higher than the heat absorption part 2a, the ratio of the portion above the liquid level in the entire core part 7 is reduced.

  At this time, since the gas-phase refrigerant condenses in a portion above the liquid level, the heat absorbed from the central processing unit 2 is radiated as condensation heat in this portion.

  On the other hand, in the part below the liquid level, only the degree of supercooling of the liquid phase refrigerant increases, and the heat absorbed from the central processing unit 2 is dissipated as sensible heat.

  Therefore, if the liquid level is positioned higher than the heat absorbing portion 2a, it is not possible to efficiently dissipate heat.

  In view of the above points, the present invention firstly provides a novel boiling-type cooling device different from the conventional one, and secondly, an object is to improve the heat dissipation capability of the boiling-type cooling device.

  In order to achieve the above object, the present invention is a boiling type cooling apparatus in which the refrigerant is boiled by heat generated in the heating element (2) to absorb heat from the heating element (2). The first refrigerant passage (3) extending in the vertical direction and through which the refrigerant for cooling the heating element (2) flows, and the first refrigerant passage (3) extending in the vertical direction on the upper end side and the lower end side of the first refrigerant passage (3). The refrigerant passage (3) communicates with the second refrigerant passage (4) for exchanging heat between the refrigerant and the cooling fluid, and heats the heating element (2) and the refrigerant in the first refrigerant passage (3). The heat absorption part (2a) to be replaced is located at substantially the same height as the refrigerant liquid level in the first refrigerant passage (3).

  By the way, if the refrigerant liquid level in the first refrigerant passage (3) is lower than the endothermic part (2a), the endothermic part (2a) will heat the vaporized refrigerant already vaporized. The heat of 2) cannot be absorbed as latent heat of vaporization, and the heat absorption capability is reduced.

  On the other hand, when the refrigerant liquid level in the first refrigerant passage (3) is made higher than the heat absorption part (2a), the heat dissipating ability is reduced as in the “problem to be solved by the invention”.

  Therefore, if the liquid level in the first refrigerant passage (3) is substantially the same as the position of the heat absorbing portion (2a), a sufficient amount of heat is radiated while efficiently absorbing heat from the heating element (2). be able to.

  The invention according to claim 2 is a boiling-type cooling device that boils the refrigerant by heat generated by the heat generating element (2) and absorbs heat from the heat generating element (2), and extends in the vertical direction, and also generates the heat generating element (2 ) And the first refrigerant passage (3) through which the refrigerant that absorbs heat circulates, communicates with the first refrigerant passage (3) at the upper end side and the lower end side of the first refrigerant passage (3) in the vertical direction, A second refrigerant passage (4) for exchanging heat with the cooling fluid, and the heat absorption part (2a) for exchanging heat between the heating element (2) and the refrigerant in the first refrigerant passage (3) as a reference. The refrigerant liquid level in the first refrigerant passage (3) is positioned within a predetermined vertical dimension range.

  Thereby, a sufficient amount of heat can be radiated while efficiently absorbing heat from the heating element (2), as in the first aspect of the invention.

  The invention according to claim 3 is characterized in that the heat absorption part (2a) is provided on the lower end side of the first refrigerant passage (3).

  Incidentally, the reference numerals in parentheses of each means described above are an example showing the correspondence with the specific means described in the embodiments described later.

  In this embodiment, the boiling type cooling apparatus according to the present invention is applied to a cooling apparatus for cooling an integrated circuit for an electronic computer such as a central processing unit (CPU).

  FIG. 1 is an external view of the boiling cooling device 1 according to the present embodiment, and FIG. 2 is a cross-sectional view taken along the line AA in FIG.

  The central processing unit 2 is an electric heating element that generates heat during operation, and the first refrigerant passage 3 is a passage through which a refrigerant that extends in the vertical direction and cools the central processing unit 2 flows as shown in FIG. The second refrigerant passage 4 is a passage that extends in the vertical direction in parallel with the first refrigerant passage 3 and communicates with the first refrigerant passage 3 on the upper end side and the lower end side of the first refrigerant passage 3. In the present embodiment, chlorofluorocarbon is used as the refrigerant.

  Specifically, the plates constituting the tubes 4a and the first refrigerant passages 3 on the upper and lower ends in the longitudinal direction of the plurality of (four in this embodiment) tubes 4a constituting the second refrigerant passages 4. First and second header tanks 5a and 5b are provided to communicate with the tube 3a.

  The first header tank 5a distributes and supplies the refrigerant to each tube 4a, and the second header tank 5b collects the refrigerant flowing out from each tube 4a and returns it to the first refrigerant passage 3, that is, the plate tube 3a. It is.

  The tube 4a is a tube having a flat cross section so that the flow direction of the cooling air is the major axis direction, and fins 6 that promote heat exchange between the refrigerant and the cooling air are formed on the flat surface. It is joined.

  A reinforcing plate 8 that reinforces the core portion 7 is provided on the side opposite to the plate tube 3a among the ends of the substantially rectangular core portion 7 including the tube 4a, the first and second header tanks 5a and 5b, and the fins 6. The reinforcing plate 8 extends in parallel with the tube 4a like a bridge connecting the first and second header tanks 5a and 5b.

  The plate tube 3a has a substantially rectangular plate shape with a refrigerant passage formed therein, and the central processing unit 2 is tightly joined to a portion corresponding to the centroid. The centroid means a position where the area moments are balanced on a plane.

  Incidentally, in the present embodiment, the plate tube 3a, the tube 4a, the first and second header tanks 5a, 5b, the fin 6 and the reinforcing plate 8 are made of a metal having high thermal conductivity such as aluminum alloy or copper, and these 3a, 4a, 5a, 5b, 6, and 8 are integrally joined by brazing.

  Here, “brazing” is a technique for joining so as not to melt the base material using brazing material or solder, as described in “connection / joining technology” (Tokyo Denki University Press). say.

  Moreover, in this embodiment, as shown in FIG. 1, it is a surface on the opposite side to the surface where the central processing unit 2 is joined among the plate tubes 3a, and is located at a position facing the centroid of the plate tube 3a. Two core portions 7 are arranged, and cooling air is blown to the two core portions 7 by a blower (not shown).

  In this embodiment, as shown in FIG. 2, the first refrigerant passage 3 has a first vertical passage within a predetermined vertical dimension range with respect to the center position of the heat absorption part 2a that exchanges heat between the central processing unit 2 and the refrigerant. The amount of refrigerant in which the liquid level height h1 of the refrigerant substantially coincides with the position of the heat absorption part 2a is placed in the boiling cooling device 1, that is, the core part 7 so that the refrigerant liquid level in the refrigerant path 3 is located. Enclosed.

  When the refrigerant is sealed in the core portion 7, it is desirable to fill the core portion 7 with a predetermined mass of refrigerant in a substantially vacuum state.

  Here, the heat absorption part 2a refers to a portion of the plate tube 3a where the central processing unit 2 is disposed. In the present embodiment, the central processing unit 2 is located at a substantially central part in the vertical direction of the first refrigerant passage 3. Has been placed.

  Next, the operation of the boiling cooling device 1 according to this embodiment will be described.

  The liquid-phase refrigerant present in the first refrigerant passage 3 is heated by the heat-absorbing part 2a to be boiled, becomes vapor refrigerant (gas-phase refrigerant), and moves upward.

  At this time, since the gas-phase refrigerant is continuously generated, the gas-phase refrigerant that has been filled in the first header tank 5a and has lost its place from the upper side to the lower side in the tube 4a that forms the second refrigerant passage 4 Flow, cooled by cooling air and condensed. And since the condensed liquid phase refrigerant becomes high in density, it flows downward due to its own weight.

  On the other hand, in the heat absorption part 2a, although the refrigerant continuously vaporizes and the liquid level tends to decrease, as described above, the refrigerant is condensed in the tube 4a, and the condensed liquid phase refrigerant flows into the heat absorption part 2a. Therefore, the refrigerant circulates in the order of the heat absorbing part 2a → the first header tank 5a → the tube 4a → the second header tank 5b → the heat absorbing part 2a.

  That is, when the liquid refrigerant is boiled and evaporated in the heat absorption part 2a, the heat of the central processing unit 2 is absorbed by the refrigerant as latent heat of evaporation.

  And in the part above the liquid level in the endothermic tube 4a, the gas phase refrigerant condenses, so that the heat absorbed from the central processing unit 2 is dissipated as cooling heat to the cooling air, while the endothermic tube 4a In the part below the liquid level, the liquid refrigerant is supercooled and the heat absorbed from the central processing unit 2 is radiated to the cooling air as sensible heat of the liquid refrigerant.

  Next, features of the present embodiment will be described.

  In the tube 4a above the liquid level, the refrigerant condenses and the heat absorbed from the central processing unit 2 is dissipated as cooling heat to the cooling air, and in the heat absorption tube 4a below the liquid level the liquid phase refrigerant. Since the heat absorbed from the central processing unit 2 is radiated to the cooling air as sensible heat of the liquid refrigerant, in order to generate a large heat radiation capacity, the condensation on the upper side of the liquid surface in the heat absorption tube 4a is condensed. What is necessary is just to make a part larger than the supercooling part below a liquid level among the endothermic tubes 4a.

  However, if the refrigerant is filled such that the refrigerant liquid surface height in the first refrigerant passage 3 is lower than the heat absorption part 2a in order to make the condensing part larger than the supercooling part, the heat absorption part 2a has already vaporized gas-phase refrigerant. Therefore, the heat of the central processing unit 2 cannot be absorbed as latent heat of vaporization, resulting in a decrease in heat absorption capability.

  On the other hand, when the refrigerant liquid surface height in the first refrigerant passage 3 is made higher than that of the heat absorbing portion 2a, the size of the condensing portion is reduced as in the conventional case, so that the heat dissipation capability is reduced.

  Therefore, if the liquid level in the first refrigerant passage 3 is substantially the same as the position of the heat absorbing portion 2a, a sufficient amount of heat can be radiated while efficiently absorbing heat from the central processing unit 2.

  As is clear from the above description, if the condensing part is made larger than the supercooling part while the liquid level is positioned on the heat absorbing part 2a, a sufficient amount of heat can be obtained while efficiently absorbing heat from the central processing unit 2. Therefore, the cooling capacity of the boiling cooling device 1 can be increased as the position of the heat absorbing portion 2a is brought closer to the lower end side of the first refrigerant passage 3.

  Incidentally, the liquid level height h1 in the first refrigerant passage 3, that is, the plate tube 3a is slightly lower than the liquid level height h2 in the second refrigerant path 4, that is, the tube 4a.

(Other embodiments)
In the above-described embodiment, the fluid in which the coolant is mixed with the rust inhibitor is used, but the present invention is not limited to this.

  In the above-described embodiment, the present invention is applied to the cooling of the central processing unit 2, but the present invention is not limited to this.

  Moreover, in the above-mentioned embodiment, although the two core parts 7 were used, this invention is not limited to this.

  In the above-described embodiment, the fins 6 are wavy, but the present invention is not limited to this, and may be, for example, pin fins, plate fins, offset fins, or the like.

  Further, the present invention is not limited to the above-described embodiment as long as it conforms to the gist of the invention described in the claims.

It is an external view of the boiling-type cooling device which concerns on embodiment of this invention. It is AA sectional drawing of FIG. It is explanatory drawing of the boiling-type cooling device which concerns on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Boiling type cooling device, 2 ... Central processing unit, 3 ... 1st refrigerant path,
3a ... plate tube, 4 ... second refrigerant passage, 4a ... tube,
5a ... 1st header tank, 5b ... 2nd header tank, 6 ... Fins,
7 ... Core part, 8 ... Reinforcing plate.

Claims (3)

A boiling-type cooling device that absorbs heat from the heating element (2) by boiling a refrigerant by heat generated in the heating element (2),
A first refrigerant passage (3) extending in the vertical direction and through which a refrigerant for cooling the heating element (2) flows;
A second refrigerant passage (4) that extends in the vertical direction and communicates with the first refrigerant passage (3) on the upper end side and the lower end side of the first refrigerant passage (3) and exchanges heat between the refrigerant and the cooling fluid. And
The heat absorption part (2a) for exchanging heat between the heating element (2) and the refrigerant in the first refrigerant passage (3) is substantially the same height as the coolant level in the first refrigerant passage (3). Boiling type cooling device characterized by being located. A boiling-type cooling device that absorbs heat from the heating element (2) by boiling a refrigerant by heat generated in the heating element (2),
A first refrigerant passage (3) that extends in the vertical direction and through which refrigerant that absorbs heat from the heating element (2) flows;
A second refrigerant passage (4) that extends in the vertical direction and communicates with the first refrigerant passage (3) on the upper end side and the lower end side of the first refrigerant passage (3) and exchanges heat between the refrigerant and the cooling fluid. And
Within the first refrigerant passage (3), the heat absorption part (2a) for exchanging heat between the heating element (2) and the refrigerant in the first refrigerant passage (3) is set within a predetermined vertical dimension range as a reference. A boiling-type cooling device, characterized in that the refrigerant liquid level is located. The boiling-type cooling device according to claim 1 or 2, wherein the heat absorption part (2a) is provided on a lower end side of the first refrigerant passage (3).

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