Heat transfer device

Abstract

Provided is a heat transfer device that can operate satisfactorily even in an environment having a freezing point or lower. A heat transfer device is provided with one or more high-temperature-side heat pipes in which a high-temperature-side working liquid is sealed, and one or more low-temperature-side heat pipes in which a low-temperature-side working liquid is sealed, the high-temperature-side working liquid being a mixed liquid comprising water and a liquid having a lower melting point than the water, the high-temperature-side heat pipe and the low-temperature-side heat pipe are at least partially in thermal contact with each other.

Description

Technical Field

[0001] The present disclosure relates to a heat transport device. Background Art

[0002] Heat transfer devices including heat pipes have been used in various fields. The heat pipes forming the heat transfer devices transfer heat generated by a heat generating element to another location for cooling.

[0003] Although heat pipes work well at room temperature, they may not work as well at low temperatures, and in some cases may not work at all.

[0004] To solve such problems, for example, Patent Document 1 describes a cooler comprising a heat pipe using water as a working fluid, a heat absorbing block attached to the heat absorbing side of the heat pipe, fins attached to the heat releasing side of the heat pipe, and a hollow tube parallel to the heat pipe, attached to the heat absorbing block and the fins, and having an enclosed space inside filled with antifreeze.

[0005] However, in the cooler of Patent Document 1, since the temperature difference in the hollow tube is large, the heat transfer characteristics in a subfreezing environment still have room for improvement.

[0006] [Prior Art Literature]

[0007] [Patent Document]

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 11-183065. Summary of the Invention

[0009] [Problems to be solved by the invention]

[0010] An object of the present disclosure is to provide a heat transport device that can function well even in sub-freezing environments.

[0011] [Technical means to solve the problem]

[0012] [1] A heat transfer device comprising one or more high-temperature side heat pipes enclosed with a high-temperature side working fluid, and one or more low-temperature side heat pipes enclosed with a low-temperature side working fluid, wherein the high-temperature side working fluid is water, and the low-temperature side working fluid is a mixture of water and a liquid having a melting point lower than that of water, and wherein at least a portion of the high-temperature side heat pipe and the low-temperature side heat pipe are in thermal contact.

[0013] [2] The heat transfer device according to [1] further comprises a heat conduction component connecting at least one of the high-temperature side heat pipes and at least one of the low-temperature side heat pipes, wherein the high-temperature side heat pipe and the low-temperature side heat pipe are in thermal contact via the heat conduction component.

[0014] [3] The heat transfer device according to [2], wherein the heat conduction member is connected to the condensation portion of the high-temperature side heat pipe and the condensation portion of the low-temperature side heat pipe.

[0015] [4] The heat transfer device according to any one of [1] to [3] above, wherein the liquid is an alcohol, a ketone, an ether, or a glycol.

[0016] [5] A heat transfer device according to any one of [1] to [4] above, wherein the liquid is an alcohol having a carbon number of 6 or less, a ketone having a carbon number of 6 or less, an ether having a carbon number of 6 or less, or a glycol having a carbon number of 6 or less.

[0017] [6] The heat transfer device according to any one of [1] to [5] above, wherein the liquid is acetone.

[0018] [7] The heat transfer device according to any one of [1] to [6] above, wherein the concentration of the liquid contained in the low-temperature side working fluid is greater than or equal to 1% by weight and less than or equal to 40% by weight.

[0019] [Effects of the Invention]

[0020] According to the present disclosure, it is possible to provide a heat transport device that can operate well even in a sub-freezing environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG. 1 is a schematic diagram showing an example of a heat transport device according to an embodiment.

[0022] FIG2 is a cross-sectional view taken along line AA of FIG1.

[0023] FIG3 is a cross-sectional view showing another example of thermal contact between a high-temperature side heat pipe and a low-temperature side heat pipe.

[0024] FIG4 is a cross-sectional view showing another example of thermal contact between a high-temperature side heat pipe and a low-temperature side heat pipe.

[0025] FIG5 is a cross-sectional view showing another example of thermal contact between a high-temperature side heat pipe and a low-temperature side heat pipe.

[0026] FIG6 is a cross-sectional view showing another example of thermal contact between a high-temperature side heat pipe and a low-temperature side heat pipe.

[0027] FIG7 is a cross-sectional view showing another example of thermal contact between a high-temperature side heat pipe and a low-temperature side heat pipe.

[0028] FIG8 is a cross-sectional view showing another example of thermal contact between a high-temperature side heat pipe and a low-temperature side heat pipe.

[0029] FIG9 is a cross-sectional view showing another example of thermal contact between a high-temperature side heat pipe and a low-temperature side heat pipe.

[0030] FIG. 10 is a schematic diagram showing another example of the heat transport device according to the embodiment.

[0031] FIG. 11 is a schematic diagram showing another example of the heat transport device according to the embodiment.

[0032] FIG. 12 is a schematic diagram showing another example of the heat transport device according to the embodiment.

[0033] FIG. 13 is a schematic diagram showing another example of the heat transport device according to the embodiment. DETAILED DESCRIPTION

[0034] The following will be described in detail based on the implementation methods.

[0035] After intensive research, the inventors of the present invention discovered that a heat transfer device having a high-temperature side heat pipe and a low-temperature side heat pipe and using a predetermined substance as the working fluid sealed in each heat pipe can operate well even in an environment below freezing. The present invention was completed based on this understanding.

[0036] A heat transfer device in an embodiment includes one or more high-temperature-side heat pipes sealed with a high-temperature-side working fluid, and one or more low-temperature-side heat pipes sealed with a low-temperature-side working fluid. The high-temperature-side working fluid is water, and the low-temperature-side working fluid is a mixture of water and a liquid having a lower melting point than water. The high-temperature-side heat pipe and the low-temperature-side heat pipe are at least partially in thermal contact.

[0037] FIG1 is a schematic diagram showing an example of a heat transfer device according to an embodiment. FIG2 is a cross-sectional view taken along line AA of FIG1 and is an example of thermal contact between a low-temperature side heat pipe 20 and a high-temperature side heat pipe 10. As shown in FIG1 and FIG2, the heat transfer device 1 according to the embodiment includes one or more high-temperature side heat pipes 10 and one or more low-temperature side heat pipes 20. Here, the following example is shown: there is one high-temperature side heat pipe 10 and one low-temperature side heat pipe 20, and the high-temperature side heat pipe 10 and the low-temperature side heat pipe 20 are arranged in parallel with each other and are in thermal contact at the evaporation section 2 and the condensation section 3 of the heat transfer device 1 respectively via a heat conductive member 4.

[0038] A high-temperature working fluid (not shown) is sealed inside the high-temperature heat pipe 10 constituting the heat transport device 1. Furthermore, a functional structure (not shown) such as a wick may be provided inside the high-temperature heat pipe 10 to induce capillary action on the high-temperature working fluid and improve heat transport characteristics.

[0039] The cross-sectional shape of the high-temperature side heat pipe 10 is not particularly limited and may be circular or flat as shown in Figure 2. Furthermore, the internal dimensions of the high-temperature side heat pipe 10 (inner diameter and width within the high-temperature side heat pipe 10) are, for example, approximately 4 to 8 mm.

[0040] The high-temperature working fluid sealed within the high-temperature heat pipe 10 is water. Pure water is preferred because, if tap water contains a large amount of impurities, there is a possibility that gas may be generated within the high-temperature heat pipe 10 with repeated use of the heat transport device 1, resulting in a decrease in the performance of the high-temperature heat pipe 10.

[0041] A low-temperature working fluid (not shown) is sealed inside the low-temperature heat pipe 20 constituting the heat transport device 1. Furthermore, a functional structure (not shown) such as a wick may be provided inside the low-temperature heat pipe 20 to induce capillary action on the low-temperature working fluid and improve heat transport characteristics.

[0042] The cross-sectional shape of the low-temperature side heat pipe 20 is not particularly limited and may be, for example, circular or flat as shown in Figure 2. Furthermore, the internal dimensions of the low-temperature side heat pipe 20 (inner diameter and width within the low-temperature side heat pipe 20) are, for example, approximately 4 to 8 mm.

[0043] The low-temperature working fluid enclosed within the low-temperature heat pipe 20 is a mixed liquid composed of water and a liquid having a lower melting point than water. This liquid, which constitutes the low-temperature working fluid, refers to the components other than water in the low-temperature working fluid (mixed liquid) within the low-temperature heat pipe 20 and is in liquid form when enclosed within the low-temperature heat pipe 20. The low-temperature working fluid within the low-temperature heat pipe 20 is different from the high-temperature working fluid within the high-temperature heat pipe 10.

[0044] The water contained in the low-temperature-side working fluid is preferably pure water because, if tap water contains a lot of impurities, there is a possibility that gas may be generated in the low-temperature-side heat pipe 20 with repeated use of the heat transport device 1, resulting in a decrease in the performance of the low-temperature-side heat pipe 20.

[0045] In the heat transfer device 1, the high-temperature side heat pipe 10 and the low-temperature side heat pipe 20 are not independently provided, but are at least partially in thermal contact. The thermal contact between the high-temperature side heat pipe 10 and the low-temperature side heat pipe 20 can also be such that the high-temperature side heat pipe 10 and the low-temperature side heat pipe 20 are in direct contact with each other. In addition, as shown in FIG1 , a heat conducting component 4 and a block (not shown) may be further provided to connect at least one of the high-temperature side heat pipes 10 and at least one of the low-temperature side heat pipes 20, and the high-temperature side heat pipe 10 and the low-temperature side heat pipe 20 can achieve thermal contact via the heat conducting component 4 or the block.

[0046] The evaporation section 2 of the heat transport device 1 receives heat generated by a heat generating element (not shown) and is composed of the evaporation section of the high-side heat pipe 10 and the evaporation section of the low-side heat pipe 20. The condensation section 3 of the heat transport device 1 releases heat from the heat generating element and is composed of the condensation section of the high-side heat pipe 10 and the condensation section of the low-side heat pipe 20. Heat generated by the heat generating element (not shown) is transferred from the evaporation section 2 of the heat transport device 1 via the high-side heat pipe 10 and the low-side heat pipe 20 to the condensation section 3 and released from the cooling surface 30.

[0047] The high-temperature-side heat pipe 10 operates better on the high-temperature side than the low-temperature-side heat pipe 20, and the low-temperature-side heat pipe 20 operates better on the low-temperature side than the high-temperature-side heat pipe 10. Furthermore, because the water in the high-temperature-side heat pipe 10 is a working fluid with a high heat transfer capacity, the heat transport device 1 exhibits excellent heat transfer characteristics at high temperatures.

[0048] Thus, in a heat transport device 1 that combines a high-side heat pipe 10 with water as the high-side working fluid and a low-side heat pipe 20 with a low-side working fluid consisting of a mixed aqueous solution of water and a liquid with a lower melting point than water, in environments below freezing, for example, the low-side heat pipe 20 primarily operates with the low-side working fluid containing the liquid with a lower melting point than water. In environments above freezing, the high-side heat pipe 10 primarily operates with water as the high-side working fluid. Consequently, the heat transport device 1 can operate well even in environments below freezing and over a wider temperature range than previously possible, particularly a wider temperature range on the low-side side. This heat transport device 1 can operate well within a temperature range of, for example, -50°C to 70°C.

[0049] Furthermore, since the temperature difference inside the high-temperature side heat pipe 10 and the low-temperature side heat pipe 20, which function as heat pipes, is smaller than the temperature difference inside a hollow pipe filled with a predetermined liquid, the high-temperature side heat pipe 10 and the low-temperature side heat pipe 20 have superior thermal responsiveness compared to the aforementioned pipes.

[0050] Furthermore, compared to heat pipes using fluorinated solvents or alcohol as working fluids, the low-temperature-side heat pipe 20, which includes a low-temperature-side working fluid with a lower melting point than water, has a greater temperature difference within the pipe. This allows heat for melting the high-temperature-side working fluid frozen in the condensation section of the high-temperature-side heat pipe 10 to be continuously supplied to at least the condensation section of the high-temperature-side heat pipe 10 via the thermal contact portion. As a result, the high-temperature-side heat pipe 10, which cannot operate below freezing, can now operate.

[0051] Furthermore, at temperatures where only the high-side heat pipe 10 would freeze, the presence of the low-side heat pipe 20 allows the high-side heat pipe 10 to continue operating, thereby expanding the temperature range within which the high-side heat pipe 10 can operate. Furthermore, due to the greater temperature difference within the low-side heat pipe 20, the operating temperature relative to the ambient temperature is higher than that of heat pipes using fluorinated solvents or alcohol as working fluids, thereby improving heat transfer.

[0052] Furthermore, the liquid in the low-temperature side working fluid having a melting point lower than that of water is preferably an alcohol, ketone, ether, or glycol. More preferably, it is an alcohol with 6 or fewer carbon atoms, a ketone with 6 or fewer carbon atoms, an ether with 6 or fewer carbon atoms, or a glycol with 6 or fewer carbon atoms. Even more preferably, it is an alcohol with 4 or fewer carbon atoms, a ketone with 4 or fewer carbon atoms, an ether with 4 or fewer carbon atoms, or a glycol with 4 or fewer carbon atoms. Because such liquids readily dissolve in water, they can improve the heat transfer characteristics and operational reliability of the low-temperature side heat pipe 20 below the freezing point. Among the above liquids, alcohols are preferred, ethers or glycols are more preferred, and ketones are even more preferred. Among the ketones, acetone is preferred. The above liquids may not be soluble and may be a combination of water and an insoluble substance.

[0053] Furthermore, the concentration of the liquid having a lower melting point than water contained in the low-temperature-side working fluid is preferably 1% by weight or more and 40% by weight or less. Specifically, when the heat transfer characteristics of the low-temperature-side heat pipe 20 are important, the concentration of the liquid in the low-temperature-side working fluid is preferably low, for example, preferably 1% by weight or more and 10% by weight or less. Furthermore, when the operational reliability of the low-temperature-side heat pipe 20 in a sub-freezing environment is important, the concentration of the liquid in the low-temperature-side working fluid is preferably high, for example, preferably 30% by weight or more and 40% by weight or less.

[0054] If the concentration of the liquid is less than 1% by weight, there is no difference in performance compared to using multiple high-side heat pipes 10, and it is difficult to continuously supply heat to dissolve the high-side working fluid frozen in the condenser portion of the high-side heat pipe 10. Furthermore, if the concentration of the liquid exceeds 40% by weight, the temperature difference within the low-side heat pipe 20 becomes excessive, and since the difference in thermal resistance between the low-side heat pipe 20 and the high-side heat pipe 10 becomes too large, heat cannot enter the low-side heat pipe 20, making it difficult to improve the heat transfer rate of the heat transfer device combined with the high-side heat pipe 10.

[0055] Furthermore, Figures 1 and 2 illustrate examples in which the high-temperature heat pipe 10 and the low-temperature heat pipe 20 are in thermal contact at the evaporator 2 and condenser 3, respectively. However, from the perspective of enabling the high-temperature heat pipe 10, which includes a high-temperature working fluid, to operate even in subfreezing environments, the heat conducting member 4 preferably connects the condenser section of the high-temperature heat pipe 10 and the condenser section of the low-temperature heat pipe 20, as shown on the left side of Figure 1. In this configuration, the heat conducting member 4 connects the condenser section of at least one high-temperature heat pipe 10 and the condenser section of at least one low-temperature heat pipe 20.

[0056] The heat conducting member 4 covers the surface of at least one high-side heat pipe 10 along the extending direction of the high-side heat pipe 10. The heat conducting member 4 also covers the surface of at least one low-side heat pipe 20 along the extending direction of the low-side heat pipe 20.

[0057] In this configuration, the high-side heat pipe 10 and the low-side heat pipe 20 are in thermal contact on the condenser section 3 side of the heat transport device 1. If the high-side heat pipe 10 and the low-side heat pipe 20 are in thermal contact at least partially in the condenser section 3, heat is transferred from the condenser section of the low-side heat pipe 20 to the condenser section of the high-side heat pipe 10 below freezing. Therefore, the high-side heat pipe 10 can operate even below freezing.

[0058] As an example of thermal contact between the high-temperature side heat pipe 10 and the low-temperature side heat pipe 20, FIG. 2 shows a circular cross-sectional shape of the high-temperature side heat pipe 10 and the low-temperature side heat pipe 20, and a structure in which the heat conductive member 4 is integrally formed. The high-temperature side heat pipe 10 and the low-temperature side heat pipe 20 disposed inside the heat conductive member 4 are independent of each other without contact. However, the structures shown in FIG. 3 to FIG. 9 are also suitable.

[0059] FIG3 shows a configuration in which the high-side heat pipe 10 and the low-side heat pipe 20 have flat cross-sectional shapes, the heat conducting member 4 is integrally formed, and the high-side heat pipe 10 and the low-side heat pipe 20 are independently disposed within the heat conducting member 4. In this configuration, the high-side heat pipe 10 and the low-side heat pipe 20 are in thermal contact with each other via the heat conducting member 4.

[0060] FIG4 shows a configuration in which the high-side heat pipe 10 and the low-side heat pipe 20 have circular cross-sections, and the heat conducting member 4 is split in half. The high-side heat pipe 10 and the low-side heat pipe 20 are disposed within the heat conducting member 4 independently of each other. In this configuration, the high-side heat pipe 10 and the low-side heat pipe 20 are in thermal contact with each other via the heat conducting member 4.

[0061] FIG5 shows a configuration in which the high-side heat pipe 10 and the low-side heat pipe 20 have circular cross-sections, the heat conducting member 4 is integrally formed, and the high-side heat pipe 10 and the low-side heat pipe 20 disposed within the heat conducting member 4 are in linear contact with each other. In this configuration, the high-side heat pipe 10 and the low-side heat pipe 20 are in direct linear contact and in thermal contact via the heat conducting member 4.

[0062] FIG6 shows a configuration in which the high-side heat pipe 10 and the low-side heat pipe 20 have circular cross-sections, the heat conductive member 4 is integrally formed, the high-side heat pipe 10 and the low-side heat pipe 20 disposed within the heat conductive member 4 are in linear contact with each other, and a heat conductive material 5 is filled near the linear contact area. In this configuration, the high-side heat pipe 10 and the low-side heat pipe 20 are in direct linear contact and in thermal contact via the heat conductive member 4 and the heat conductive material 5.

[0063] FIG. 7 shows a configuration in which the high-side heat pipe 10 and the low-side heat pipe 20 have flat cross-sectional shapes, and the flat plate-shaped heat conductive member 4 supporting the flat portion of the high-side heat pipe 10 and the flat plate-shaped heat conductive member 4 supporting the flat portion of the low-side heat pipe 20 are in contact with each other. In this configuration, the high-side heat pipe 10 and the low-side heat pipe 20 are in thermal contact with each other via the heat conductive member 4.

[0064] FIG8 shows a configuration in which the high-side heat pipe 10 and the low-side heat pipe 20 have flat cross-sectional shapes, and a heat conductive member 4 (e.g., a U-shaped heat conductive member 4) that covers a portion of the high-side heat pipe 10 and supports the flat portion of the high-side heat pipe 10 is in contact with a heat conductive member 4 that covers a portion of the low-side heat pipe 20 and supports the flat portion of the low-side heat pipe 20. In this configuration, the high-side heat pipe 10 and the low-side heat pipe 20 are in thermal contact with each other via the heat conductive member 4.

[0065] FIG. 9 shows a configuration in which the high-side heat pipe 10 and the low-side heat pipe 20 have flat cross-sectional shapes, and the heat conductive member 4 extending through the high-side heat pipe 10 and the heat conductive member 4 extending through the low-side heat pipe 20 are in contact with each other. In this configuration, the high-side heat pipe 10 and the low-side heat pipe 20 are in thermal contact via the heat conductive member 4.

[0066] Regarding the above-mentioned structure, the cross-sectional shape of the high-temperature side heat pipe 10 and the low-temperature side heat pipe 20, the structure of the heat-conducting component 4, whether or not to fill the heat-conducting material 5, etc. can also be appropriately changed. For example, the high-temperature side heat pipe 10 and the low-temperature side heat pipe 20 do not need to be cylindrical, but can be square, or can have different shapes depending on the position, or can have greatly different cross-sectional areas. In addition, the high-temperature side heat pipe 10 and the low-temperature side heat pipe 20 are not integral components, but can be obtained by assembling metal components. In addition, the evaporation portion and the condensation portion do not have to be located in one place, but can be located in multiple places, or can be located at any position.

[0067] As described above, when the high-temperature-side heat pipe 10 and the low-temperature-side heat pipe 20 are in thermal contact with each other, the high-temperature-side heat pipe 10 and the low-temperature-side heat pipe 20 may be in direct contact with each other, the high-temperature-side heat pipe 10 and the low-temperature-side heat pipe 20 may be in contact with each other via the heat-conducting member 4, or the high-temperature-side heat pipe 10 and the low-temperature-side heat pipe 20 may be in contact with each other via the heat-conducting material 5. Furthermore, the heat-conducting member 4 and the heat-conducting material 5 may be used together.

[0068] Regarding the coverage of the heat-conducting member 4 on the surface of the high-temperature side heat pipe 10 and the coverage of the heat-conducting member 4 on the surface of the low-temperature side heat pipe 20, from the perspective of ensuring good heat transfer between the high-temperature side heat pipe 10 and the low-temperature side heat pipe 20, the coverage of the heat-conducting member 4 on the entire circumference of each tube of the high-temperature side heat pipe 10 and the low-temperature side heat pipe 20 is preferably at least 10% or more, and more preferably 100% as shown in Figure 2, etc. In addition, the coverage length of the heat-conducting member 4 along the extending direction of each tube is preferably, for example, 5 mm or more. In addition, for example, if the coverage area of ​​the heat-conducting member 4 on each tube is 200 mm 2 As described above, heat can be transferred well between the high-temperature side heat pipe 10 and the low-temperature side heat pipe 20. The coverage of the heat conductive material 5 and the like are also the same as those of the heat conductive member 4 described above.

[0069] The heat conductive member 4 is preferably a metal member (metal block) made of a copper-based material such as copper or a copper alloy, or an aluminum-based material such as aluminum or an aluminum alloy. If the heat conductive member 4 is made of a copper-based material, the heat transfer characteristics of the heat transport device 1 can be further improved. If the heat conductive member 4 is made of an aluminum-based material, the weight of the heat transport device 1 can be reduced while maintaining the good heat transfer characteristics of the heat transport device 1. Furthermore, such a heat conductive member 4 can also serve as both a high-temperature-side heat pipe 10 and a low-temperature-side heat pipe 20.

[0070] The heat conductive material 5 is preferably solder or grease, more preferably solder.

[0071] Furthermore, from the perspective of improving the heat transfer characteristics of the heat transfer device 1, the high-temperature-side heat pipe 10 and the low-temperature-side heat pipe 20 are preferably arranged in one of the following configurations: Specifically, the high-temperature-side heat pipe 10 and the low-temperature-side heat pipe 20 are preferably arranged horizontally and in parallel in the vertical direction, as shown in FIG. 1 ; the high-temperature-side heat pipe 10 and the low-temperature-side heat pipe 20 are preferably arranged horizontally and in parallel in the horizontal direction, as shown in FIG. 10 ; or the high-temperature-side heat pipe 10 and the low-temperature-side heat pipe 20 are preferably arranged vertically and in parallel in the horizontal direction, as shown in FIG. 11 .

[0072] In addition, the forms of such multiple configurations can also be connected to each other as shown in Figure 12. In this case, as shown in Figure 12, it is preferred that the corner 11 of the connection portion in the high-temperature side heat pipe 10 is a rounded shape. Similarly, it is preferred that the corner 21 of the connection portion of the low-temperature side heat pipe 20 is a rounded shape. If the corners 11 and 21 provided between the evaporation section 2 and the condensation section 3 of the heat transport device 1 are rounded, the high-temperature side working fluid in the high-temperature side heat pipe 10 can flow well through the corner 11, and the low-temperature side working fluid in the low-temperature side heat pipe 20 can flow well through the corner 21. Therefore, the good heat transfer characteristics of the heat transport device 1 can be fully maintained. Although Figure 12 shows an example of the forms of two configurations connected at right angles via the corners 11 and 21, the connection angle of the forms of the two configurations is not particularly limited and may not be a right angle.

[0073] Furthermore, when the high-temperature-side heat pipe 10 and the low-temperature-side heat pipe 20 are stacked in the vertical direction, from the perspective of utilizing the temperature difference of the low-temperature-side heat pipe 20 to allow the high-temperature-side heat pipe 10 to operate well, it is preferred that the low-temperature-side heat pipe 20 be closer to the cooling surface 30 than the high-temperature-side heat pipe 10. In other words, it is preferred that the heat pipe closer to the cooling source side be the low-temperature-side heat pipe 20. Furthermore, from the perspective of allowing the heat transport device 1 to maintain good thermal performance in a high-temperature environment, it is preferred that the high-temperature-side heat pipe 10, as shown in FIG1 , be closer to the cooling surface 30 and closer to the heat source than the low-temperature-side heat pipe 20. In a high-temperature environment, the high-temperature-side heat pipe 10 has a higher thermal impedance than the low-temperature-side heat pipe 20. Therefore, by utilizing the configuration shown in FIG1 to more effectively cool the high-temperature-side heat pipe 10, it is possible to allow the high-temperature-side heat pipe 10 to operate well.

[0074] Furthermore, when the heat transport device 1 includes a plurality of low-temperature-side heat pipes 20, from the perspective of allowing the high-temperature-side heat pipe 10 to operate efficiently at low temperatures, it is preferable to arrange the high-temperature-side heat pipe 10 in parallel with two low-temperature-side heat pipes 20 sandwiching the high-temperature-side heat pipe 10, as shown in FIG. 13 .

[0075] Furthermore, when the heat transport device 1 needs to operate in a top heating configuration (a configuration in which the heat source is on top and the cooling surface is on the bottom), it is desirable to fill the entire length of the interior of each of the high-temperature side heat pipe 10 and the low-temperature side heat pipe 20 with a sintered body.

[0076] According to the above embodiment, by having a high-temperature side heat pipe and a low-temperature side heat pipe and using a predetermined substance as the working fluid sealed in each heat pipe, the heat transport device can operate well not only in a room temperature environment but also in an environment below freezing.

[0077] Although the embodiments have been described above, the present disclosure is not limited to the above embodiments, but includes the concepts of the present disclosure and all aspects included in the scope of the patent application, and various modifications can be made within the scope of the present disclosure.

[0078] Reference numerals

[0079] 1: Heat transfer device

[0080] 2: Evaporation section

[0081] 3: Condensation section

[0082] 4: Heat conduction components

[0083] 5: Heat conduction material

[0084] 10: High temperature side heat pipe

[0085] 11: Corner of the high-temperature side heat pipe

[0086] 20: Low temperature side heat pipe

[0087] 21: Corner of the low-temperature side heat pipe

[0088] 30: Cooling surface

Claims

1. A heat transfer device comprising: One or more high-temperature side heat pipes sealed with high-temperature side working fluid, and One or more low-temperature side heat pipes sealed with low-temperature side working fluid, The aforementioned high temperature side working fluid is water, The low-temperature side working fluid is a mixture of water and a liquid having a melting point lower than that of water. The high-temperature side heat pipe and the low-temperature side heat pipe are in thermal contact with each other at least partially.

2. The heat transport device according to claim 1, further comprising a heat conducting member connecting at least one of the high-temperature side heat pipes and at least one of the low-temperature side heat pipes. The high-temperature-side heat pipe and the low-temperature-side heat pipe are in thermal contact with each other via the heat-conducting member.

3. The heat transport device according to claim 1, wherein: The heat conducting member is connected to the condensation portion of the high-temperature side heat pipe and the condensation portion of the low-temperature side heat pipe.

4. The heat transport device according to claim 1, wherein The aforementioned liquid is alcohol, ketone, ether, or glycol.

5. The heat transport device according to claim 1, wherein: The liquid is an alcohol having 6 or less carbon atoms, a ketone having 6 or less carbon atoms, an ether having 6 or less carbon atoms, or a glycol having 6 or less carbon atoms.

6. The heat transport device according to claim 1, wherein: The aforementioned liquid is acetone.

7. The heat transport device according to any one of claims 1 to 6, wherein: The concentration of the liquid contained in the low-temperature-side working fluid is 1% by weight or more and 40% by weight or less.

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