Evaporator and hybrid loop heat pipe

Abstract

To provide an evaporator and a hybrid loop heat pipe that can maximize cooling performance for a sheet-like heat source. [Solution] The evaporator comprises an internal liquid flow path which is a flow path through which a liquid-phase working fluid flowing in from the outside moves, a storage section connected to the internal liquid flow path and which stores the liquid-phase working fluid, a wick structure which moves the liquid-phase working fluid in the internal liquid flow path near an external heat source by capillary force, and a vaporization section which has a gas-liquid separation section which evaporates the liquid-phase working fluid moved by the wick structure by the heat of the heat source and discharges it to the outside, and is characterized in that in the vaporization section, the wick structure surrounds the gas-liquid separation section, the internal liquid flow path surrounds the vaporization section, and the storage section surrounds the internal liquid flow path, and the direction in which the gas-liquid separation section discharges the gas-phase working fluid is opposite to the direction in which the liquid-phase working fluid flows into the internal liquid flow path.

Description

[Technical Field]

[0001] The present invention relates to an evaporator and a hybrid loop heat pipe. [Background technology]

[0002] In recent years, with the miniaturization and high performance of semiconductor devices, the amount of heat generated from heat sources such as central processing units (CPUs) and graphics processing units (GPUs) in electrical devices is increasing. Furthermore, with the recent rise of generative AI, the amount of heat generated from CPUs and GPUs is expected to increase further. Therefore, a heat transport device that can efficiently cool the heat source is required. Conventionally, heat pipes, vapor chambers, loop heat pipes, and the like are known as heat transport devices.

[0003] These heat transport devices use latent heat, which is the thermal energy absorbed or released when the working fluid changes phase, rather than sensible heat, which is the thermal energy that accompanies a temperature change, to release heat generated from the heat source to the outside of electrical equipment, etc. These heat transport devices do not require a power source. In heat transport devices that use latent heat, temperature changes in the heat source impair cooling performance, so maintaining a constant temperature of the heat source is important for improving cooling performance.

[0004] Furthermore, in heat transport devices, an increase in the amount of heat generated from the heat source can cause the amount of vapor inside the device to exceed a certain level, leading to a state known as the "evaporation limit." At this state, the working fluid no longer circulates smoothly through the heat transport device, and the liquid phase working fluid is depleted, resulting in a decline in cooling performance. Therefore, it is important to design heat transport devices in a way that prevents them from reaching this state.

[0005] In addition, as electrical equipment and the like are becoming smaller in size, there is a demand for heat transport devices to be smaller as well. Furthermore, along with the miniaturization of electrical equipment and the like, devices that distribute heat sources have also appeared in recent years. Therefore, there is a demand for heat transport devices that can be optimally designed according to the heat sources contained in electrical equipment and the like.

[0006] Patent Document 1 discloses a technology for providing an evaporator and a loop heat pipe that are compact yet capable of cooling with high heat exchange efficiency. Specifically, Patent Document 1 discloses a technology for an evaporator that includes a hollow cylindrical evaporator body whose front end communicates with a vapor pipe and whose rear end is connected to a liquid return pipe and closed, a cylindrical wick inserted therein, an uneven grooved portion provided longitudinally on the outer circumferential surface of the wick, a non-grooved portion integrated with the rear end of the grooved portion, and a bayonet tube. The evaporator performs cooling by utilizing the latent heat generated when the working fluid evaporates. With this configuration, the evaporator of Patent Document 1 can suppress temperature changes in the heat source and improve heat exchange efficiency.

[0007] Furthermore, Patent Document 2 discloses a hybrid loop heat pipe with a reservoir in the evaporator. The hybrid loop heat pipe is a loop heat pipe in which the reservoir is provided in the evaporator, and the direction in which the working fluid moves through the vapor flow path and the direction in which the working fluid moves through the liquid flow path are opposite to each other. This configuration allows the hybrid loop heat pipe of Patent Document 2 to smoothly circulate the working fluid and improve cooling performance. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-315740 [Patent Document 2] U.S. Patent No. 6,926,072 Summary of the Invention [Problem to be solved by the invention]

[0009] However, the techniques disclosed in Patent Documents 1 and 2 are based on a three-dimensional structure and cannot be applied to a sheet-like structure. For this reason, when these techniques are directly applied to a sheet-like heat source such as a CPU or GPU, there is a problem in that the maximum cooling performance cannot be obtained.

[0010] The present invention was devised in consideration of the above-mentioned problems, and its purpose is to provide an evaporator and a hybrid loop heat pipe that can maximize cooling performance for a sheet-shaped heat source. [Means for solving the problem]

[0011] The evaporator according to the first aspect of the present invention comprises an internal liquid flow path which is a flow path through which a liquid-phase working fluid flowing in from the outside moves, a storage section connected to the internal liquid flow path and storing the liquid-phase working fluid that has flowed into the internal liquid flow path, a wick structure which moves the liquid-phase working fluid in the internal liquid flow path to the vicinity of an external heat source by capillary force, and a vaporization section which has a gas-liquid separation section which evaporates the liquid-phase working fluid moved by the wick structure by heat from the heat source and discharges the gas-phase working fluid to the outside, and is characterized in that in the vaporization section, the wick structure surrounds the gas-liquid separation section, the internal liquid flow path surrounds the vaporization section, and the storage section surrounds the internal liquid flow path, and the direction in which the gas-liquid separation section discharges the gas-phase working fluid and the direction in which the liquid-phase working fluid flows into the internal liquid flow path are opposite to each other.

[0012] An evaporator according to a second aspect of the present invention is the evaporator of the first aspect of the present invention, characterized in that the internal liquid flow path and the reservoir are separated by a wick that is a porous body.

[0013] The evaporator according to a third aspect of the present invention is characterized in that, in the first aspect of the present invention, the internal liquid flow path takes in the liquid-phase working fluid flowing in from the outside from a plurality of locations, and the internal liquid flow path and the storage section are connected at a confluence section where the liquid-phase working fluids that have flowed into the internal liquid flow path converge.

[0014] An evaporator according to a fourth aspect of the present invention is the evaporator according to the first aspect of the present invention, characterized in that the gas-liquid separation section has a shape that spreads out radially, fan-like, or dendritic from a certain point.

[0015] A hybrid loop heat pipe according to a fifth aspect of the present invention comprises a condenser that liquefies a gas phase working fluid, an external liquid flow path through which the working fluid liquefied by the condenser moves, an evaporator that evaporates the liquid phase working fluid flowing from the external liquid flow path, and an external vapor flow path through which the working fluid evaporated by the evaporator moves and which connects the evaporator and the condenser, wherein the evaporator comprises an internal liquid flow path through which the liquid phase working fluid flowing from the external liquid flow path moves, a storage section connected to the internal liquid flow path and storing the liquid phase working fluid that has flowed into the internal liquid flow path, and a storage section in the internal liquid flow path. The vaporization unit has a wick structure that moves the liquid phase working fluid near an external heat source by capillary force, and a gas-liquid separation unit that evaporates the liquid phase working fluid moved by the wick structure using heat from the heat source and discharges the gas phase working fluid to the external vapor flow path, wherein in the vaporization unit, the wick structure surrounds the gas-liquid separation unit, the internal liquid flow path surrounds the vaporization unit, and the storage unit surrounds the internal liquid flow path, and the direction in which the gas phase working fluid moves through the external vapor flow path and the direction in which the liquid phase working fluid moves through the external liquid flow path are opposite to each other.

[0016] A hybrid loop heat pipe according to a sixth aspect of the present invention is the hybrid loop heat pipe according to the fifth aspect of the present invention, characterized in that the volume of the storage section is larger than the volume of the external vapor flow path.

[0017] A hybrid loop heat pipe according to a seventh aspect of the present invention is the hybrid loop heat pipe according to the fifth aspect of the present invention, characterized in that the external vapor flow path and the external liquid flow path are included in a single tube.

[0018] The hybrid loop heat pipe of the eighth invention is characterized in that, in the fifth invention, the external liquid flow path and the external vapor flow path are formed by a wick made of silicon, resin, rubber, metal, or a porous material.

[0019] A ninth aspect of the present invention is a hybrid loop heat pipe according to the fifth aspect of the present invention, characterized in that, in the condenser, the external vapor flow path and the external liquid flow path meander within a plane. [Effects of the Invention]

[0020] According to the first to fourth inventions, in the evaporation section, the wick structure surrounds the gas-liquid separation section, the internal liquid flow path surrounds the evaporation section, and the storage section surrounds the internal liquid flow path. This allows the evaporator to have a thin sheet-like form. Furthermore, the evaporator can move the working fluid near the heat source by utilizing the pressure of the liquid-phase working fluid flowing into the internal liquid flow path. This allows the evaporator to maximize its cooling performance for a sheet-like heat source.

[0021] In particular, according to the second aspect of the present invention, the internal liquid flow path and the reservoir are separated by a porous wick. Therefore, the liquid-phase working fluid in the evaporator moves between the internal liquid flow path and the reservoir due to capillary force. Therefore, even if the liquid-phase working fluid in the internal liquid flow path decreases, the evaporator can replenish the working fluid from the reservoir. This further improves the evaporator's ability to discharge heat from the heat source to the outside.

[0022] In particular, according to the third aspect of the present invention, the internal liquid flow path takes in liquid-phase working fluid flowing in from the outside through multiple locations, and the internal liquid flow path and the reservoir are connected at the confluence where the liquid-phase working fluids that have flowed into the internal liquid flow path join. Therefore, the evaporator can split the pressure of the working fluid at the confluence into two, the reservoir side and the gas-liquid separation side. Furthermore, the evaporator can increase the pressure of the working fluid flowing into the gas-liquid separation part while guiding the working fluid to the reservoir. This allows the evaporator to efficiently move the liquid-phase working fluid near the heat source, further improving its ability to discharge heat from the heat source to the outside.

[0023] In particular, according to the fourth aspect of the present invention, the gas-liquid separation section has a shape that spreads out radially, fan-like, or dendritic from a certain point. This allows the gas-liquid separation section to efficiently utilize the heat of the heat source to evaporate the liquid-phase working fluid. This further improves the evaporator's ability to discharge the heat of the heat source to the outside.

[0024] According to the fifth to ninth inventions, the evaporator has a wick structure surrounding a gas-liquid separation section in the evaporation section, an internal liquid flow path surrounding the evaporation section, and a storage section surrounding the internal liquid flow path. This allows the evaporator to take on a thin, sheet-like form. Furthermore, the hybrid loop heat pipe can circulate the working fluid by utilizing the pressure of the liquid-phase working fluid flowing into the evaporator. This allows the hybrid loop heat pipe to maximize its cooling performance for a sheet-shaped heat source.

[0025] In particular, according to the sixth aspect of the present invention, the volume of the reservoir is larger than the volume of the external vapor flow path. This allows the reservoir to store a large amount of liquid working fluid, making it less likely to run out of liquid working fluid, and the hybrid loop heat pipe is less likely to reach its dissipation limit. This further improves the hybrid loop heat pipe's ability to discharge heat from the heat source to the outside.

[0026] In particular, according to the seventh aspect of the present invention, the external vapor flow path and the external liquid flow path are included in a single pipe. This allows the hybrid loop heat pipe to be easily installed inside electrical equipment, etc. This allows users to easily use the hybrid loop heat pipe even in electrical equipment with limited space.

[0027] In particular, according to the eighth aspect of the present invention, the external liquid flow path and the external vapor flow path are formed by a wick made of silicon, resin, rubber, metal, or a porous material. Therefore, the hybrid loop heat pipe can prevent the liquid phase working fluid from entering the external vapor flow path and the gas phase working fluid from entering the external liquid flow path. This further improves the hybrid loop heat pipe's ability to discharge heat from the heat source to the outside.

[0028] In particular, according to the ninth aspect of the present invention, in the condenser, the external vapor flow path and the external liquid flow path meander within a plane. This allows the condenser to have a thin sheet-like shape. Furthermore, the condenser liquefies the gas-phase working fluid by moving it in a meandering manner, thereby releasing heat to the outside. This makes it possible for the hybrid loop heat pipe to be easily used in electrical equipment, etc., and further improves the performance of dissipating heat from the heat source to the outside. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a schematic diagram showing an example of the overall configuration of a hybrid loop heat pipe according to the present invention. [Figure 2] FIG. 2 is a schematic diagram showing an example of an evaporator according to the present invention. [Figure 3] Figure 3(a) is a schematic diagram showing an example of the structure of the wick structure and gas-liquid separation unit of the present invention, and Figure 3(b) is a schematic diagram showing a modified example of the structure of the wick structure and gas-liquid separation unit of the present invention. [Figure 4]Figure 4(a) is a schematic diagram showing an example of a gas-liquid separation section having a shape that spreads out radially from a certain point, Figure 4(b) is a schematic diagram showing an example of a gas-liquid separation section having a shape that spreads out in a dendritic manner from a certain point, and Figure 4(c) is a schematic diagram showing a modified shape of the gas-liquid separation section. [Figure 5] FIG. 5 is a schematic diagram showing an example of a condenser according to the present invention. [Figure 6] FIG. 6 is a schematic diagram showing an example of a transport pipe corresponding to an evaporator according to the present invention. [Figure 7] FIG. 7 is a schematic diagram showing an example of the overall configuration of a hybrid loop heat pipe when it has a three-dimensional structure. [Figure 8] FIG. 8 is a schematic diagram showing an example of a cross section of a transport pipe corresponding to a hybrid loop heat pipe when it has a three-dimensional structure. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, an embodiment of an evaporator 1 and a hybrid loop heat pipe 100 to which the present invention is applied will be described in detail with reference to the drawings.

[0031] <Hybrid Loop Heat Pipe 100> FIG. 1 is a schematic diagram showing an example of the overall configuration of a hybrid loop heat pipe 100 according to the present invention.

[0032] The hybrid loop heat pipe 100 is a device that cools an external heat source 4 by dissipating heat generated by the heat source 4 to the outside. Here, the working fluid is a medium that transports heat, such as water, alcohol, a mixture of water and alcohol, or ammonia. As shown in Figure 1, the hybrid loop heat pipe 100 has various flow paths in a sealed space through which the working fluid moves.

[0033] 1, the hybrid loop heat pipe 100 includes an evaporator 1, a condenser 2, and a transport pipe 3, and the evaporator 1 and the condenser 2 are connected by the transport pipe 3. The transport pipe 3 also has an external liquid flow path 31 and an external vapor flow path 32.

[0034] In Fig. 1, the heat source 4 is a heat-generating component or part in an electric device, such as a CPU, a GPU, or a power semiconductor module. In Fig. 1, the heat source 4 is sheet-shaped. The evaporator 1 is installed so as to be in close contact with the heat source 4. For example, in Fig. 1, the evaporator 1 is installed on top of the heat source 4.

[0035] (Description of each element of the present invention) The evaporator 1, the condenser 2, and the transport pipe 3, which are the elements in FIG. 1, will be described below.

[0036] <Evaporator 1> The evaporator 1 is a mechanism that evaporates a liquid-phase working fluid and changes it into a gas-phase working fluid. The evaporator 1 is installed so as to be in close contact with a heat source 4. The evaporator 1 is also connected to a transport pipe 3.

[0037] Fig. 2 is a schematic diagram showing an example of an evaporator 1 according to the present invention. As shown in Fig. 2, the evaporator 1 includes an internal liquid flow path 11, a storage section 12, and a vaporization section 13. Here, the vaporization section 13 has a wick structure 14 and a gas-liquid separation section 15. The internal liquid flow path 11 and the storage section 12 are connected to each other. Furthermore, the internal liquid flow path 11 is connected to an external liquid flow path 31 of a transport pipe 3 connected to the evaporator 1, and the vaporization section 13 is connected to an external vapor flow path 32 of a transport pipe 3 connected to the evaporator 1.

[0038] The evaporator 1 shown in Fig. 2 is in the form of a thin sheet. In Figs. 1 and 2, the evaporator 1 may be surrounded by a housing made of metal or the like (not shown). The thickness of the sheet-like evaporator 1 may be 0.2 mm or less.

[0039] The internal liquid flow path 11 is a flow path through which a liquid-phase working fluid flows in from the outside. For example, the liquid-phase working fluid flows into the internal liquid flow path 11 from the external liquid flow path 31.

[0040] The reservoir 12 is a space for storing the working fluid. The reservoir 12 is connected to the internal liquid flow path 11, and stores the liquid-phase working fluid that has flowed into the internal liquid flow path 11.

[0041] The vaporization section 13 is a section that evaporates the liquid-phase working fluid by the heat of the heat source 4, and has a wick structure 14 and a gas-liquid separation section 15.

[0042] Here, the wick structure 14 is a porous structure formed by a wick. The wick structure 14 uses capillary force to suck up the liquid-phase working fluid in the internal liquid flow path 11 and move it to the gas-liquid separation unit 15 located near the heat source 4. Here, the wick is a porous body made of metal such as copper or nickel, ceramic, resin, etc. Furthermore, capillary force is a force that acts to move the liquid through the fine gaps in the porous body. Hereinafter, when referring to wicks collectively, they will be referred to as wicks without a reference symbol, and when referring to a wick shown in the drawings, they will be referred to as wick 5. Furthermore, in Figure 2, the shaded portion may be a wick.

[0043] Here, the gas-liquid separation unit 15 has a gas-liquid separation structure and is a porous structure formed by a wick. The gas-liquid separation unit 15 evaporates the liquid-phase working fluid transferred by the wick structure 14 using the heat of the heat source 4 and discharges the gas-phase working fluid to the outside. For example, the gas-liquid separation unit 15 is connected to the external steam flow path 32 and discharges the gas-phase working fluid to the external steam flow path 32. Here, the gas-liquid separation structure may be, for example, a wick structure in which a layer having fine pores and retaining the liquid-phase working fluid is disposed on the outside and a layer having coarse pores and allowing vapor to pass through is disposed on the inside. Also, as shown in FIGS. 1 and 2, the evaporator 1 may be installed so that the gas-liquid separation unit 15 is positioned in close contact with the heat source 4. Also, as shown in FIG. 2, the area of ​​the gas-liquid separation unit 15 in the evaporator 1 may be approximately the same as the area of ​​the heat source 4.

[0044] The detailed structure and function of the evaporator 1 will be described below.

[0045] As shown in FIG. 2, in the evaporation section 13, the wick structure 14 surrounds the gas-liquid separation section 15. Furthermore, the internal liquid flow path 11 surrounds the evaporation section 13. Furthermore, the storage section 12 surrounds the internal liquid flow path 11. Furthermore, the direction in which the gas-liquid separation section 15 discharges the gas-phase working fluid to the external vapor flow path 32 and the direction in which the liquid-phase working fluid flows from the external liquid flow path 31 into the internal liquid flow path 11 are opposite to each other. Furthermore, the evaporator 1 and the elements that constitute the evaporator 1 are not limited to being circular as shown in FIG. 2. They may be polygonal, for example.

[0046] As shown in Fig. 2, the internal liquid flow path 11 and the reservoir 12 may be separated by a wick 5. The reservoir 12 may also be designed so as not to be affected by heat generated from the heat source 4 in Fig. 1 or other heat sources. The wick 5 moves the liquid-phase working fluid from the reservoir 12 to the internal liquid flow path 11 by capillary force.

[0047] 2, the internal liquid flow path 11 may take in the liquid-phase working fluid flowing in from the outside through a plurality of locations. For example, the internal liquid flow path 11 may take in the liquid-phase working fluid from two locations connected to the external liquid flow path 31 as shown in FIG. 2. In this case, the liquid-phase working fluids that have flowed into the internal liquid flow path 11 join in the vicinity of the joining section 16 in FIG. 2. Here, the joining section 16 is a location where the liquid-phase working fluids that have flowed into the evaporator 1 join together. As shown in FIG. 2, the internal liquid flow path 11 and the reservoir section 12 may be connected at the joining section 16.

[0048] The wick structure 14 and the gas-liquid separation unit 15 may have various structures depending on the environment in which the evaporator 1 is used, the shape of the heat source 4, and the like. For example, FIG. 3(a) is a schematic diagram showing an example of the structure of the wick structure 14 and the gas-liquid separation unit 15 according to the present invention. As shown in FIG. 3(a), the evaporator 1 is installed so that the position where the gas-liquid separation unit 15 is located is in close contact with the heat source 4. Also, as shown in FIG. 3(a), the wick structure 14 may be structured to surround the upper part of the gas-liquid separation unit 15. In this case, an internal liquid flow path 11 may be provided on the wick structure 14. When the wick structure 14 and the gas-liquid separation unit 15 have such a structure, the evaporator 1 has improved performance in moving the working fluid from the wick structure 14 to the gas-liquid separation unit 15.

[0049] 3(b) is a schematic diagram showing a modified example of the structure of the wick structure 14 and the gas-liquid separation unit 15 according to the present invention. As shown in FIG. 3(b), the wick structure 14 does not have to be formed above the gas-liquid separation unit 15. When the wick structure 14 and the gas-liquid separation unit 15 have such a structure, the sheet-like evaporator 1 becomes thinner.

[0050] The shape and size of the gas-liquid separation section 15 in FIGS. 1 and 2 may take various forms depending on the shape of the heat source 4, the amount of heat generated from the heat source 4, and the like. For example, in the vaporization section 13, the larger the area of ​​the gas-liquid separation section 15, the more effectively the heat generated from the heat source 4 is utilized. Furthermore, for example, the larger the surface area of ​​the portion where the gas-liquid separation section 15 and the wick structure 14 contact, the more easily the working fluid moves from the internal liquid flow path 11 to the gas-liquid separation section 15. Furthermore, for example, the shorter the distance between the gas-liquid separation section 15 and the internal liquid flow path 11, the more quickly the working fluid moves to the gas-liquid separation section 15, and the more effectively the liquid-phase working fluid evaporates. Furthermore, for example, if the area of ​​the gas-liquid separation section 15 is approximately the same as the area of ​​the heat source 4, as shown in FIG. 1, the heat generated from the heat source 4 can be effectively utilized.

[0051] For example, FIG. 4( a) is a schematic diagram showing an example of a gas-liquid separation unit 15 having a shape that spreads radially from a certain point. A gas-liquid separation unit 15 having such a shape can effectively utilize the heat generated from the heat source 4 when the area of ​​the heat source 4 is small. FIG. 4( b) is a schematic diagram showing an example of a gas-liquid separation unit 15 having a shape that spreads in a dendritic manner from a certain point. A gas-liquid separation unit 15 having such a shape can shorten the distance between the internal liquid flow path 11 and the gas-liquid separation unit 15, thereby effectively utilizing the heat generated from the heat source 4. Furthermore, a gas-liquid separation unit 15 having such a shape has a large surface area at the contact point between the gas-liquid separation unit 15 and the wick structure 14, making it easier for the working fluid to move from the internal liquid flow path 11 to the gas-liquid separation unit 15. Furthermore, FIG. 4( c) is a schematic diagram showing a modified shape of the gas-liquid separation unit 15. A gas-liquid separation unit 15 having such a shape is effective when the area of ​​the heat source 4 is large. The gas-liquid separation unit 15 may also have a shape that spreads fan-like from a certain point. As shown in FIGS. 4(a) to 4(c), the gas-liquid separation unit 15 is connected to the external steam flow path 32, and the gas-phase working fluid is discharged to the external steam flow path 32.

[0052] <Condenser 2> The condenser 2 is a mechanism that liquefies the gaseous working fluid by dissipating the heat of the working fluid that has become gaseous in the evaporator 1 to the outside. The condenser 2 is connected to a transport pipe 3, and has an internal condenser flow path 7 through which the working fluid flows.

[0053] FIG. 5 is a schematic diagram showing an example of a condenser 2 according to the present invention. As shown in FIG. 5, the condenser 2 is in the form of a thin sheet and has an internal condenser flow path 7 formed by a wick. In addition to the wick, the internal condenser flow path 7 may be formed from silicon, resin, rubber, metal, or the like that does not generate non-condensable gases during the manufacturing process of the hybrid loop heat pipe 100. The outside of the condenser 2 may be surrounded by a housing made of metal or the like (not shown in FIG. 5).

[0054] In the condenser 2, the gas-phase working fluid flows from the external vapor flow path 32 into the condenser internal flow path 7. The gas-phase working fluid releases heat to the outside and is liquefied while passing through the condenser internal flow path 7. The liquefied working fluid passes through the condenser internal flow path 7 and is discharged to the external liquid flow path 31.

[0055] 5, the condenser flow path 7 may meander within a plane. This lengthens the condenser flow path 7. As a result, the gas-phase working fluid releases heat sufficiently within the condenser flow path 7 and changes into a liquid.

[0056] If the condenser 2 alone is not able to dissipate heat sufficiently, the condenser 2 may be provided with a heat sink or the like having heat dissipation fins. If heat dissipation fins are provided, the heat dissipation capacity of the condenser 2 will be improved by natural air cooling by the fins. Also, the condenser 2 may be provided with an electric fan or the like. If a fan is provided, the heat dissipation capacity of the condenser 2 will be improved by forced air cooling by the fan.

[0057] <Transport pipe 3> The transport pipe 3 connects the evaporator 1 and the condenser 2 and is a pipe through which the working fluid travels. The transport pipe 3 may be straight or curved. The transport pipe 3 is connected to the evaporator 1 and the condenser 2 so as not to generate non-condensable gases during the manufacture of the hybrid loop heat pipe 100.

[0058] Fig. 6 is a schematic diagram showing an example of a transport pipe 3 according to the present invention. As shown in Fig. 6, the transport pipe 3 includes an external liquid flow path 31 and an external vapor flow path 32 inside one pipe. Here, the external liquid flow path 31 is a flow path through which the working fluid liquefied by the condenser 2 moves. Furthermore, the external vapor flow path 32 is a flow path through which the working fluid evaporated by the evaporator 1 moves. The external liquid flow path 31 and the external vapor flow path 32 connect the evaporator 1 and the condenser 2.

[0059] The external liquid flow path 31 allows the liquid-phase working fluid to move from the condenser internal flow path 7 of the condenser 2 to the internal liquid flow path 11 of the evaporator 1. The external vapor flow path 32 allows the gas-phase working fluid to move from the gas-liquid separation section 15 of the evaporator 1 to the condenser internal flow path 7 of the condenser 2. Here, as shown in FIG. 6 , the direction in which the gas-phase working fluid moves through the external vapor flow path 32 and the direction in which the liquid-phase working fluid moves through the external liquid flow path 31 are opposite to each other.

[0060] As shown in Fig. 6, in the transport pipe 3, the external liquid flow path 31 and the external vapor flow path 32 may be formed by the wick 5. In addition to the wick 5, the external liquid flow path 31 and the external vapor flow path 32 may be formed to maintain airtightness using silicon, resin, rubber, metal, or the like that does not generate non-condensable gases during the manufacturing process of the hybrid loop heat pipe 100. This separates the external liquid flow path 31 and the external vapor flow path 32, preventing the gas-phase working fluid and the liquid-phase working fluid from mixing. In addition, the outside of the transport pipe 3 may be surrounded by a housing made of metal or the like (not shown in Fig. 6).

[0061] Below, a specific example will be described of cooling a heat source 4 using a hybrid loop heat pipe 100 including an evaporator 1, a condenser 2, and a transport pipe 3. For the sake of explanation, the operation of the hybrid loop heat pipe 100 will be described in steps 1 to 4.

[0062] <Step 1> First, the liquid-phase working fluid flows from the external liquid flow path 31 of the transport pipe 3 into the internal liquid flow path 11. Here, the internal liquid flow path 11 takes in the liquid-phase working fluid flowing in from the outside from multiple locations. The liquid-phase working fluids taken in from multiple locations join together near the confluence 16 in Figure 2.

[0063] In the internal liquid flow path 11, a force acts due to capillary force to move the liquid-phase working fluid from the internal liquid flow path 11 to the gas-liquid separation section 15 via the wick structure .

[0064] Because the internal liquid flow path 11 and the reservoir 12 are connected at the confluence 16, a portion of the liquid-phase working fluid that joins the internal liquid flow path 11 near the confluence 16 flows into the reservoir 12. Meanwhile, as the liquid-phase working fluid joins, the pressure of the liquid-phase working fluid increases in the direction from the internal liquid flow path 11 to the wick structure 14 near the confluence 16. As a result, a force acts to move the liquid-phase working fluid from the internal liquid flow path 11 to the gas-liquid separation section 15 via the wick structure 14. This force is in addition to the force generated by capillary force.

[0065] In this way, due to capillary force and the pressure caused by the working fluids joining at the joining section 16, the liquid-phase working fluid moves from the internal liquid flow path 11 to the gas-liquid separation section 15 near the heat source.

[0066] <Step 2> Next, the gas-liquid separation unit 15 evaporates the liquid-phase working fluid using the heat generated from the heat source 4. As a result, the evaporated working fluid is discharged to the external vapor flow path 32 of the transport pipe 3.

[0067] The working fluid discharged from the gas-liquid separation section 15 to the external steam flow path 32 moves through the external steam flow path 32 of the transport pipe 3 to the condenser 2. Then, the gas-phase working fluid flows from the external steam flow path 32 into the condenser internal flow path 7 of the condenser 2.

[0068] <Step 3> The gas-phase working fluid that has flowed into the condenser internal flow path 7 of the condenser 2 moves within the condenser internal flow path 7, which meanders within a plane, as shown in Figure 5. As the working fluid moves through the condenser internal flow path 7, it releases heat to the outside and is liquefied. The working fluid that has become liquefied within the condenser internal flow path 7 moves through the condenser internal flow path 7 as is and is discharged into the external liquid flow path 31 of the transport pipe 3.

[0069] <Step 4> The liquid-phase working fluid discharged from the condenser internal flow path 7 of the condenser 2 to the external liquid flow path 31 of the transport pipe 3 moves through the external liquid flow path 31 to the evaporator 1. The liquid-phase working fluid that has moved to the evaporator 1 flows into the internal liquid flow path 11 of the evaporator 1.

[0070] By repeating the above steps 1 to 4, the heat generated from the heat source 4 is continuously released to the outside, and the heat source 4 is cooled.

[0071] In the evaporator 1, the internal liquid flow path 11 and the reservoir 12 are connected near the confluence 16. Therefore, in the evaporator 1, the pressure caused by the liquid-phase working fluids converging at the confluence 16 can be divided into two parts, the reservoir 12 side and the gas-liquid separation part 15 side. As a result, the evaporator 1 can guide the working fluid to the reservoir 12, while increasing the pressure at which the working fluid moves to the gas-liquid separation part 15 via the wick structure 14.

[0072] In steps 1 to 4, when the amount of heat generated by the heat source 4 is large, the gas-liquid separation unit 15 evaporates a large amount of working fluid and discharges a large amount of gas-phase working fluid to the external vapor flow path 32. As a result, the pressure inside the hybrid loop heat pipe 100 increases, and the liquid-phase working fluid in the internal liquid flow path 11 moves more easily to the gas-liquid separation unit 15.

[0073] Here, a large amount of gas-phase working fluid is discharged into the external vapor flow path 32, which increases the pressure of the working fluid moving inside the external vapor flow path 32, the condenser flow path 7, and the external liquid flow path 31. As a result, the working fluid circulates smoothly in the hybrid loop heat pipe 100.

[0074] When the amount of liquid-phase working fluid in the internal liquid flow path 11 decreases due to an increase in the amount of heat generated by the heat source 4, the working fluid in the reservoir 12 is replenished to the internal liquid flow path 11. By replenishing the working fluid from the reservoir 12, the working fluid is prevented from running out, and the hybrid loop heat pipe 100 can be prevented from reaching the scattering limit.

[0075] In this way, the hybrid loop heat pipe 100 can prevent the heat source 4 from reaching the scattering limit even when the amount of heat generated by the heat source 4 is large, and can maintain a stable high cooling capacity by smoothly circulating the working fluid.

[0076] Furthermore, in the evaporator 1, the wick structure 14 of the evaporation section 13 surrounds the gas-liquid separation section 15, the internal liquid flow path 11 surrounds the evaporation section 13, and the storage section 12 surrounds the internal liquid flow path 11, so that the person designing the evaporator 1 can easily adjust the size and shape of the internal liquid flow path 11, the storage section 12, and the evaporation section 13 according to the amount of heat generated from the heat source 4, the allowable size of the evaporator 1, etc.

[0077] For example, the larger the storage portion 12 of the evaporator 1, the more working fluid it can hold, resulting in stable cooling capacity. Therefore, if the amount of heat generated by the heat source 4 is large, the user of the evaporator 1 can increase the outermost diameter of the storage portion 12 to stabilize cooling performance. Furthermore, because the storage portion 12 is located at the outermost part of the evaporator 1, the user of the evaporator 1 can significantly change the volume occupied by the storage portion 12 in the evaporator 1 simply by slightly changing the outermost diameter. In this way, the user of the evaporator 1 can adjust the cooling capacity of the hybrid loop heat pipe 100 according to the heat source 4 without increasing the size of the evaporator 1.

[0078] For example, in the hybrid loop heat pipe 100, the volume of the reservoir 12 may be larger than the volume of the external vapor flow path 32. In this case, the hybrid loop heat pipe 100 can hold a large amount of working fluid, resulting in stable cooling performance.

[0079] The widths of the external liquid flow path 31, the external vapor flow path 32, and the condenser flow path 7 may be designed according to the amount of working fluid flowing through the flow paths. For example, if a large amount of working fluid flows through the hybrid loop heat pipe 100, these flow paths may be designed to be wide.

[0080] (3D Hybrid Loop Heat Pipe 100) So far, the sheet-shaped evaporator 1 and the sheet-shaped hybrid loop heat pipe 100 have been described, but the evaporator 1 and the hybrid loop heat pipe 100 according to the present invention may have a three-dimensional structure.

[0081] FIG. 7 is a schematic diagram showing an example of the overall configuration of a hybrid loop heat pipe 100 with a three-dimensional structure. Similar to the hybrid loop heat pipe 100 shown in FIG. 1, the hybrid loop heat pipe 100 includes an evaporator 1, a condenser 2, and a transport pipe 3. The structure of the evaporator 1 may be a thicker version of the sheet-like evaporator 1 shown in FIG. 2. The structure of the condenser 2 may be a thicker version of the sheet-like condenser 2 shown in FIG. 3. Furthermore, in the condenser 2, the internal condenser flow path 7 is not limited to being within a single plane, but may meander throughout the entire interior of the condenser 2.

[0082] The transport tube 3 may also have a pipe-like structure. FIG. 8 is a schematic diagram showing an example of a cross section of the transport tube 3 corresponding to the three-dimensional hybrid loop heat pipe 100. The transport tube 3 in FIG. 8 has an external vapor channel 32 in the center and multiple external liquid channels 31 around the external vapor channel 32. The external vapor channel 32 and the external liquid channel 31 are formed by a wick 5. The outside of the transport tube 3 may be covered by a metal tube 6. The metal tube 6 may be a tube made of the same metal as the wick. In FIG. 8, the multiple external liquid channels 31 may be a single large external liquid channel 31 surrounding the external vapor channel 32. The portion formed by the wick 5 may be a silicone tube, a resin tube, a rubber tube, a metal pipe, or the like that does not generate non-condensable gases during the manufacturing process of the hybrid loop heat pipe 100.

[0083] Based on the configuration of the evaporator 1, condenser 2, and transport pipe 3 described above, the hybrid loop heat pipe 100 of the present invention can be made smaller than conventional loop heat pipes, even when designed with a three-dimensional structure.

[0084] The hybrid loop heat pipe 100 designed with a three-dimensional structure can replace water-cooled heat sinks, particularly sheet-type microchannel water-cooled heat sinks, used in data centers and other facilities. A microchannel water-cooled heat sink is a sheet-type water-cooled heat sink with many microchannels through which water flows to cool a heat source 4. The microchannel water-cooled heat sink is a heat transport device that utilizes sensible heat, which is heat associated with temperature changes in water. Although microchannel water-cooled heat sinks require a pump to circulate water, they are used in data centers and other facilities because they require little space near the heat source. The hybrid loop heat pipe 100 designed with a three-dimensional structure according to the present invention can be made smaller than conventional loop heat pipes and can therefore replace microchannel water-cooled heat sinks. Furthermore, when the hybrid loop heat pipe 100 is used, the pump required for microchannel water-cooled heat sinks can be eliminated.

[0085] (Effects Obtained by the Present Invention) According to the present invention, in the evaporation section 13, the wick structure 14 surrounds the gas-liquid separation section 15, the internal liquid flow path 11 surrounds the evaporation section 13, and the storage section 12 surrounds the internal liquid flow path 11. Therefore, the evaporator 1 can be in the form of a thin sheet. Furthermore, the evaporator 1 can move the working fluid near the heat source 4 by utilizing the pressure of the liquid-phase working fluid flowing into the internal liquid flow path 11. This allows the evaporator 1 to maximize its cooling performance for the sheet-shaped heat source 4.

[0086] Furthermore, according to the present invention, the internal liquid flow path 11 and the reservoir 12 are separated by the wick 5, which is a porous material. Therefore, the liquid-phase working fluid in the evaporator 1 moves between the internal liquid flow path 11 and the reservoir 12 due to capillary force, so that the evaporator 1 can replenish the working fluid from the reservoir 12 even if the liquid-phase working fluid in the internal liquid flow path 11 decreases. This further improves the evaporator 1's ability to discharge heat from the heat source 4 to the outside.

[0087] Furthermore, according to the present invention, the internal liquid flow path 11 takes in the liquid-phase working fluid flowing in from the outside from multiple locations, and the internal liquid flow path 11 and the storage section 12 are connected at the confluence section 16 where the liquid-phase working fluids taken into the internal liquid flow path 11 join. Therefore, the evaporator 1 can divide the pressure of the working fluid into two at the confluence section 16, that is, into the storage section 12 side and the gas-liquid separation section 15 side. Furthermore, the evaporator 1 can increase the pressure of the working fluid flowing into the gas-liquid separation section 15 while guiding the working fluid to the storage section 12. This allows the evaporator 1 to efficiently move the liquid-phase working fluid to the vicinity of the heat source 4, further improving the performance of discharging heat from the heat source 4 to the outside.

[0088] Furthermore, according to the present invention, the gas-liquid separation section 15 has a shape that spreads out radially, fan-like, or dendritic from a certain point. Therefore, the gas-liquid separation section 15 can efficiently use the heat of the heat source 4 to evaporate the liquid-phase working fluid. This further improves the performance of the evaporator 1 in discharging the heat of the heat source 4 to the outside.

[0089] Furthermore, according to the present invention, the evaporator 1 has a wick structure 14 surrounding a gas-liquid separation section 15 in the evaporation section 13, an internal liquid flow path 11 surrounding the evaporation section 13, and a storage section 12 surrounding the internal liquid flow path 11. This allows the evaporator 1 to have a thin, sheet-like form. Furthermore, the hybrid loop heat pipe 100 can circulate the working fluid by utilizing the pressure of the liquid-phase working fluid flowing into the evaporator 1. This allows the hybrid loop heat pipe 100 to maximize its cooling performance for a sheet-like heat source 4.

[0090] Furthermore, according to the present invention, the volume of the reservoir 12 is larger than the volume of the external vapor flow path 32. This allows the reservoir 12 to store a large amount of liquid-phase working fluid, which is less likely to run out, making the hybrid loop heat pipe 100 less likely to reach its scattering limit. This further improves the hybrid loop heat pipe 100's ability to discharge heat from the heat source 4 to the outside.

[0091] Furthermore, according to the present invention, the external vapor flow path 32 and the external liquid flow path 31 are included in a single pipe. This allows the hybrid loop heat pipe 100 to be easily installed inside an electrical device, etc. This allows users of the hybrid loop heat pipe 100 to easily use the hybrid loop heat pipe 100 even when the available space in the electrical device, etc. is small.

[0092] Furthermore, according to the present invention, the external liquid flow path 31 and the external vapor flow path 32 are formed by a wick, which is a porous material. Therefore, the hybrid loop heat pipe 100 can prevent the liquid-phase working fluid from entering the external vapor flow path 32 and the gas-phase working fluid from entering the external liquid flow path 31. This further improves the hybrid loop heat pipe 100's ability to discharge heat from the heat source 4 to the outside.

[0093] Furthermore, according to the present invention, in the condenser 2, the external vapor flow path 32 and the external liquid flow path 31 meander within a plane. This allows the condenser 2 to have a thin sheet-like shape. Furthermore, the condenser 2 moves the gas-phase working fluid in a meandering manner, thereby dissipating heat to the outside and liquefying the working fluid. This allows the hybrid loop heat pipe 100 to be easily used in electrical equipment, etc., and further improves the performance of dissipating heat from the heat source 4 to the outside.

[0094] According to the present invention, the evaporator 1 includes a reservoir 12. Therefore, when the liquid-phase working fluid in the internal liquid flow path 11 decreases, the working fluid in the reservoir 12 is replenished to the internal liquid flow path 11. By replenishing the working fluid from the reservoir 12, the working fluid is prevented from running out. As a result, the evaporator 1 and the hybrid loop heat pipe 100 can cool the heat source 4 without reaching the scattering limit.

[0095] According to the present invention, the wick structure 14 surrounds the gas-liquid separation section 15, the internal liquid flow path 11 surrounds the vaporization section 13, and the storage section 12 surrounds the internal liquid flow path 11. The sizes of the internal liquid flow path 11, the storage section 12, the wick structure 14, and the gas-liquid separation section 15 affect the cooling performance of the hybrid loop heat pipe 100. Therefore, users of the hybrid loop heat pipe 100 can design the hybrid loop heat pipe 100 to meet the size and cooling performance requirements of the usage environment by adjusting the size of each section without changing the technical concept of the invention. This allows the hybrid loop heat pipe 100 to be applied in a wide range of applications, from sheet-shaped ones for mobile devices to three-dimensional structures for data centers.

[0096] According to the present invention, non-condensable gases remaining in the hybrid loop heat pipe 100 during manufacturing are collected in the reservoir 12 of the evaporator 1. This allows the hybrid loop heat pipe 100 to function without impeding the operation of the internal liquid flow path 11 or the vaporization section 13. Furthermore, in the hybrid loop heat pipe 100 according to the present invention, even when the heat source 4 begins to generate heat, the working fluid is instantly supplied to the gas-liquid separation section 15 from the internal liquid flow path 11 via the wick structure 14. This allows the hybrid loop heat pipe 100 to instantly cool the heat source 4 and suppress temperature changes in the heat source 4.

[0097] According to the present invention, when the amount of heat generated by the heat source 4 is large, the pressure of the working fluid in the hybrid loop heat pipe 100 increases. This allows the working fluid to circulate smoothly within the hybrid loop heat pipe 100. As a result, the hybrid loop heat pipe 100 can suppress temperature changes in the heat source 4 even when the amount of heat generated is large.

[0098] Although an embodiment of the present invention has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. This novel embodiment can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. This embodiment and its modifications are included within the scope and spirit of the invention, and are also included in the invention described in the claims and their equivalents. [Explanation of symbols]

[0099] 1: Evaporator 2: Condenser 3: Transport pipe 4:Heat source 5: Wick 6:Metal tube 7: Flow path inside the condenser 11: Internal liquid flow path 12: Storage section 13: Vaporization section 14: Wick structure 15: Gas-liquid separation section 16: Junction 31: External liquid flow path 32: External steam flow path 100: Hybrid loop heat pipe

Claims

1. an internal liquid flow path that is a flow path through which a liquid-phase working fluid flowing in from the outside moves; a reservoir connected to the internal liquid flow path and configured to store the liquid-phase working fluid that has flowed into the internal liquid flow path; a wick structure that moves the liquid-phase working fluid in the internal liquid flow path to the vicinity of an external heat source by capillary force, and a vaporization unit that includes a gas-liquid separation unit that evaporates the liquid-phase working fluid moved by the wick structure by heat from the heat source and discharges the gas-phase working fluid to the outside, In the vaporization section, the wick structure surrounds the gas-liquid separation section, the internal liquid flow path surrounds the vaporization section, the reservoir surrounds the internal liquid flow path; a direction in which the gas-liquid separation unit discharges the gas-phase working fluid and a direction in which the liquid-phase working fluid flows into the internal liquid flow path are opposite to each other; An evaporator characterized by:

2. The internal liquid flow path and the reservoir are separated by a wick that is a porous material.

2. The evaporator according to claim 1,

3. The internal liquid flow path takes in the liquid-phase working fluid flowing in from the outside through a plurality of portions, The internal liquid flow path and the reservoir are connected at a confluence portion where the liquid-phase working fluids that have flowed into the internal liquid flow path are converged.

2. The evaporator according to claim 1,

4. The gas-liquid separation section has a shape that spreads radially, fan-like, or dendritic from a certain point.

2. The evaporator according to claim 1,

5. a condenser that liquefies the gas phase working fluid; an external liquid flow path that is a flow path through which the working fluid liquefied by the condenser moves; an evaporator that evaporates the liquid-phase working fluid that flows in from the external liquid flow path; an external vapor flow path through which the working fluid evaporated by the evaporator moves, the external vapor flow path connecting the evaporator and the condenser; The evaporator comprises: an internal liquid flow path which is a flow path through which the working fluid in a liquid phase flowing in from the external liquid flow path moves; a reservoir connected to the internal liquid flow path and configured to store the liquid-phase working fluid that has flowed into the internal liquid flow path; a vaporization unit having a wick structure that moves the working fluid in a liquid phase in the internal liquid flow path to the vicinity of an external heat source by capillary force, and a gas-liquid separation unit that evaporates the working fluid in the liquid phase moved by the wick structure by heat from the heat source and discharges the working fluid in a gas phase to the external vapor flow path, In the vaporization section, the wick structure surrounds the gas-liquid separation section, the internal liquid flow path surrounds the vaporization section, the reservoir surrounds the internal liquid flow path; The direction in which the gas-phase working fluid moves through the external vapor flow path and the direction in which the liquid-phase working fluid moves through the external liquid flow path are opposite to each other. Hybrid loop heat pipe featuring.

6. The volume of the reservoir is greater than the volume of the external steam flow path. The hybrid loop heat pipe according to claim 5,

7. The external vapor flow path and the external liquid flow path are contained in one tube. The hybrid loop heat pipe according to claim 5,

8. The external liquid flow path and the external vapor flow path are formed by a wick made of silicon, resin, rubber, metal, or a porous material. The hybrid loop heat pipe according to claim 5,

9. the condenser has an internal condenser flow path through which the working fluid flows, The flow path in the condenser meanders within a plane. The hybrid loop heat pipe according to claim 5,

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