JP2008292116A - Cooling apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling apparatus for cooling a heating element during heat generation from the heating element and retaining heat in the heating element during no heat generation from the heating element. <P>SOLUTION: The cooling apparatus 10 cools the heating element 12 by evaporating a coolant stored in an evaporator 14 by heat from the heating element 12 to radiate the heat by a condenser 16 during heat generation from the heating element 12. During no heat generation from the heating element 12, a catalyst in the evaporator 12 stops evaporating and thereby the cooling apparatus 10 stops cooling by the catalyst. Then, vacuum hollow grains 32 in the evaporator 14 act as an heat-insulating layer to retain the heat in the heating element 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cooling device that cools a heating element, and more particularly to a device that uses a heat pipe that moves heat using a refrigerant.

  A heat pipe is a device that moves heat from a hot part of a pipe to a cold part by a refrigerant moving in the pipe. In the high-temperature part, the liquid-phase refrigerant evaporates and the gas-phase refrigerant is sent to the low-temperature part where it liquefies and returns to the high-temperature part. A heat pipe of a type in which a flow path from a high temperature part to a low temperature part and a flow path to return from the low temperature part to the high temperature part are separately provided and the refrigerant circulates in one direction in this flow path is known. ing. A cooling device using this circulation type heat pipe has been proposed. The portion of the heat pipe that receives heat from the heating element becomes the high-temperature portion, and the portion that dissipates heat becomes the low-temperature portion.

  Patent Document 1 listed below discloses a cooling device that dissipates heat by moving heat of an automobile interior material heated by sunlight using a circulation type heat pipe to the outside of the passenger compartment.

JP 2006-125783 A

  The cooling device using the heat pipe is efficiently cooled when the heating element is cooled. However, when the heating element does not generate heat and there is a demand to maintain the temperature up to that point (keep warm), it is disadvantageous because of the good heat dissipation of the heat pipe. Generally, in order to keep an object warm, a technique for providing a heat insulating layer made of a heat insulating material on the surface of the object is known, and in a heating element to be cooled by a cooling device using the above heat pipe Similarly, if a heat insulating layer is provided, the heat retention can be improved. However, a heat pipe and a heat insulating material are arranged around the heating element, and the outer shape of the apparatus is increased.

  The present invention provides a cooling device having high cooling performance when the heating element is generating heat, and also having high heat retention performance for maintaining a high temperature until then when the heating element stops generating heat. I will provide a.

  The present invention stores a refrigerant, heats the refrigerant by a heating element, evaporates the evaporator, condenses the condensed refrigerant, connects the evaporator and the condenser, and circulates the refrigerant. The evaporator includes a container that forms a chamber for storing a refrigerant between the heater and a vacuum hollow particle that is held in the chamber and that is evacuated. The refrigerant flows through the gaps between the vacuum hollow particles.

  The circulation path includes a liquid flow path through which the refrigerant condensed from the condenser to the evaporator flows, and a valve that opens and closes the liquid flow path, and when the temperature of the heating element is a predetermined value or less, The valve can be closed.

  Moreover, each said vacuum hollow particle can be arranged so that it may be in point contact or line contact with respect to a heat generating body and the said adjacent vacuum hollow particle.

  Further, the container of the evaporator can be formed of a flexible film.

  Moreover, the refrigerant | coolant enclosed in this cooling device can be pressure-reduced.

  The cooling device of the present invention has a high cooling performance when the heating element is generating heat, and also has a high heat retention performance for maintaining the high temperature until then when the heating element does not generate heat. Can have.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a cooling device 10 according to the present embodiment.

  The cooling device 10 includes an evaporator 14 that heats and evaporates the refrigerant by the heating element 12, a condenser 16 that condenses the evaporated refrigerant, and a tank 18 that stores the condensed refrigerant. The evaporator 14, the condenser 16, and the tank 18 are connected by a circulation path 20 through which the refrigerant circulates. The evaporator 14 has a container 30 provided so as to surround the heating element 12, and a chamber 28 for storing a refrigerant is formed between the evaporator 14 and the evaporator 14.

  The circulation path 20 includes a gas flow path 22 in which a refrigerant (gas refrigerant) evaporated in the evaporator 14 into a gas phase flows to the condenser 16, and a refrigerant (liquid) condensed in the condenser 16 into a liquid phase. The refrigerant) has a liquid flow path 24 that returns to the evaporator 14 via the tank 18. The condenser 16 is disposed at a higher position than the evaporator 14. Therefore, the ends of the gas flow path 22 and the liquid flow path 24 connected to the condenser 16 are higher than the ends connected to the evaporator 14. The tank 18 is disposed at a height between the evaporator 14 and the condenser 16. The refrigerant that has become gas and becomes lighter in the evaporator 14 moves up the gas flow path 22 and reaches the condenser 16. The refrigerant that has become liquid in the condenser 16 flows through the liquid flow path 24 to the tank 18 by gravity and then returns to the evaporator 14. In this way, the refrigerant circulates through the circulation path 20.

  The liquid flow path 24 connected between the tank 18 and the evaporator 14 is provided with a valve 26 for opening and closing the liquid flow path 24. An example of the configuration of the valve 26 will be described with reference to the drawings. 2 is a cross-sectional view showing the configuration of the valve 26 in the closed state, and FIG. 3 is a cross-sectional view showing the configuration of the valve 26 in the open state.

  The valve 26 includes a valve body 36, a valve box 38 that divides the internal space into two by this, and a thermo element 34 that drives the valve body 36 according to a target temperature. The liquid flow path 24 connected to the tank 18 is connected to one of the two spaces of the valve box 38 partitioned by the valve body 36, and the liquid flow path 24 connected to the evaporator 14 is connected to the other. The two spaces are connected (see FIG. 3) and separated (see FIG. 2) depending on the position of the valve body 36, and the liquid channel 24 is opened and closed by selecting this state.

  The thermo element 34 is provided with a heat receiving portion 40 that encloses wax and that contacts the target heating element 12 and receives heat. Further, a valve shaft 36 a integrated with the valve body 36 is inserted into the space in which the wax of the thermo element 34 is sealed. When the heat receiving unit 40 is heated by receiving heat from the heating element 12, the wax is also heated, and the volume of the wax itself increases. Due to the expansion of the wax, the valve shaft 36a is moved so as to be pushed out from the thermo element 34. At the same time, the valve body 36 is moved to the position shown in FIG. 3, and the valve 26 is opened. When the temperature of the heating element 12 decreases, the temperature of the heat receiving portion 40 and the wax decreases, and the valve element 36 and the valve shaft 36a are moved to the position shown in FIG. It becomes a state.

  In the present embodiment, in order to promote the movement of heat, it is necessary to make only the gas refrigerant and the liquid refrigerant in the circulation path of the refrigerant. Moreover, it is necessary to use the phase change of the refrigerant in order to increase the efficiency of heat dissipation. For this purpose, the pressure in the path through which the refrigerant circulates is reduced. By this decompression, unnecessary gas (air, etc.) in the path is removed, and at the same time, the saturated vapor pressure is lowered, the boiling point is lowered, and a phase change of the refrigerant can be caused at a desired temperature. The refrigerant type and the refrigerant pressure are determined based on the amount of heat generated by the heating element, the temperature of the environment, and the like. As an example of the refrigerant, an alternative chlorofluorocarbon such as Fluorinert (registered trademark) can be used. Water can also be used.

  FIGS. 4 and 5 are diagrams showing changes over time in the heating element temperature and the condenser temperature. FIG. 4 shows the case where the refrigerant pressure is atmospheric pressure, and FIG. 5 shows the case where the refrigerant pressure is reduced. The time change of the heating element temperature is represented by a curve indicated by reference numeral 50, and the time change of the condenser temperature is indicated by a curve indicated by reference numeral 52. When the refrigerant pressure is atmospheric pressure, as shown in FIG. 4, the condenser temperature does not change at about 20 ° C., and it can be seen that the heat of the heating element 12 is not moving, that is, the heating element 12 is not cooled. . When the refrigerant pressure is reduced, the condenser temperature rises from about 20 ° C. to about 60 ° C. as shown in FIG. 5, and it can be seen that heat transfer occurs.

  The condenser 16 has a heat dissipation structure that widens the outer surface area and dissipates the heat of the refrigerant. This heat dissipation structure is, for example, a heat dissipation fin (not shown) provided on the outer periphery of the condenser 16. The heat radiating fin is made of a material having good thermal conductivity, for example, metal (copper, aluminum, etc.). The heat radiation fin dissipates the heat of the gas refrigerant to the outside, and the gas refrigerant condenses into a liquid refrigerant.

  The container 30 of the evaporator 14 is made of a film material made of a flexible material. This can be, for example, a polymer film. Since the container 30 has flexibility, the chamber 28 can be easily formed in accordance with the shape of the heating element 12. The container 30 has a metal film (not shown) formed by attaching a metal to its outer layer. This metal film reflects radiant heat from inside the evaporator 14. Therefore, since the radiant heat which evaporator 14 emits decreases, heat retention performance improves.

  In the chamber 28, vacuum hollow particles 32 whose interior is evacuated are provided. The vacuum hollow particles 32 are made of glass, and the shape thereof is formed in a vacuum furnace. FIG. 6 shows an example of the shape of the vacuum hollow particles 32. As shown in FIG. 6, the vacuum hollow particles 32 can be spherical, cylindrical or cuboid. In addition, the vacuum hollow particle 32 in this embodiment is spherical. The vacuum hollow particles 32 have a size corresponding to the shape of the heating element 12, for example, a size of 1 to 3 mm. Moreover, the inside of the vacuum hollow particle 32 is a medium or high vacuum state, and an internal pressure is 0.01-1 Pa, for example. Such a vacuum hollow particle 32 becomes an element of a heat insulating material, and a heat insulating layer is formed by collecting a plurality of these.

  7 and 8 are views showing an example of the outer peripheral surface of the heating element 12 and the vacuum hollow particles 32 arranged on the outer peripheral surface. FIG. 7 shows the wires 60 arranged on the outer peripheral surface of the heating element 12 at equal intervals. The interval between the wires 60 is the same as the outer diameter of the vacuum hollow particles 32. By arranging the vacuum hollow particles 32 in the recesses formed between the wires 60, the vacuum hollow particles 32 can be easily arranged on the outer peripheral surface of the heating element 12. Further, FIG. 8 shows grooves 62 formed at equal intervals on the outer peripheral surface of the heating element 12. The interval between the grooves 62 is the same as the outer shape of the vacuum hollow particles 32. By disposing the vacuum hollow particles 32 in the grooves 62, the vacuum hollow particles 32 can be easily arranged on the outer peripheral surface of the heating element 12.

  By stacking the vacuum hollow particles 32 on the vacuum hollow particles 32 arranged on the outer peripheral surface of the heating element 12, a heat insulating layer made of the vacuum hollow particles 32 is formed. Since the heat insulation layer includes a vacuum portion in the vacuum hollow particles 32, the heat retaining property is good. Further, in this heat insulating layer, a gap is formed between the vacuum hollow particles 32. Through this gap, the refrigerant can flow.

  The vacuum hollow particles 32 are fixed to the heating element 12 and the adjacent vacuum hollow particles 32 by an adhesive. As this adhesive, an adhesive having a high viscosity that hardly causes capillary action is used. Thereby, it can suppress that an adhesive agent enters into the clearance gap between the vacuum hollow particles 32 used as the flow path of a refrigerant | coolant, and plugs there. Since the vacuum hollow particles 32 are fixed to the heating element 12 and the adjacent vacuum hollow particles 32 by this adhesive, the vacuum hollow particles 32 are prevented from flowing out from the chamber 28 to the circulation path 20. That is, the vacuum hollow particles 32 are held in the chamber 28 by the adhesive. In addition, by providing a mesh member having holes smaller than the vacuum hollow particles 32 at the connection port where the circulation path 20 is connected to the evaporator 14, the vacuum hollow from the chamber 28 to the circulation path 20 can be achieved without using an adhesive. The outflow of the particles 32 is prevented, and the vacuum hollow particles 32 can be held in the chamber.

  The heat insulating layer formed by the vacuum hollow particles 32 is configured such that the portion of the particle main body that comes into contact is reduced. Specifically, the vacuum hollow particles 32 are arranged to be in point contact or line contact with the heating element 12 and the adjacent vacuum hollow particles 32. When the vacuum hollow particle 32 is spherical, the contact partner is a point contact such as a spherical, flat or solid corner. When the vacuum hollow particles 32 are cylindrical, the contact between the curved surfaces of the cylindrical tube portions arranged in parallel with each other and the contact between the curved surface of the cylindrical tube portion and the flat surface is a line contact. Thus, by arranging the vacuum hollow particles 32 so as to be in point contact or line contact, the area of the portion where the solid and the solid are in contact with each other is reduced. As a result, heat conduction through the solid is suppressed. In general, solids have better heat conduction than gas, and heat retention can be effectively improved by suppressing heat conduction in this part.

  Next, the operation of the cooling device 10 will be described separately when the heating element 12 generates heat and when the heating element 12 stops generating heat.

  First, the operation of the cooling device 10 when the heating element 12 is generating heat will be described. Since the temperature of the heating element 12 increases due to heat generation, the valve 26 that senses the temperature is opened, and the liquid refrigerant is sent from the tank 18 to the evaporator 14 via the liquid channel 24. The liquid refrigerant sent to the evaporator 14 receives the heat of the heating element 12 and evaporates to change into a gaseous refrigerant. The gaseous refrigerant moves from the evaporator 14 to the condenser 16 via the gas flow path 22. In the condenser 16, the heat of the gaseous refrigerant is radiated to the outside, and the gaseous refrigerant is condensed to change into a liquid refrigerant. Then, the liquid refrigerant flows into the tank 18 via the liquid flow path 24 and is stored there. As described above, the refrigerant circulates in the circulation path 20 while changing the phase, whereby the heat of the heating element 12 is radiated to the outside and the heating element 12 is cooled.

  Next, the operation of the cooling device 10 when the heating element 12 stops generating heat will be described. When the heating element 12 does not generate heat, the heating element 12 is cooled by the refrigerant, and the temperature of the heating element 12 decreases. When the temperature falls below a predetermined value, the valve 26 that senses the temperature is closed and the flow of the liquid refrigerant in the liquid flow path 24 stops, so that the liquid refrigerant is not supplied to the evaporator 14. The remaining liquid refrigerant in the evaporator 14 evaporates due to the residual heat of the heating element 12, and the liquid refrigerant in the evaporator 14 disappears or becomes little. When the liquid refrigerant is exhausted, cooling of the heating element 12 by the refrigerant stops. Further, the vacuum hollow particles 32 in the evaporator 14 become a heat insulating layer, and the heat generating body 12 in a state where the temperature is still high is kept warm.

  According to the cooling device 10 according to the present embodiment, since the evaporator 14 has the refrigerant stored therein and the heat insulating layer made of the vacuum hollow particles 32, the heating element 12 can be cooled by the refrigerant, and further the vacuum. The heating element 12 can be kept warm by the hollow particles 32. Further, since the inside of the vacuum hollow particles 32 is in a vacuum state with good heat retention performance, the thickness of the heat insulating layer can be reduced, and the outer shape of the cooling device 10 can be reduced.

  Since the cooling device 10 of the present invention has high cooling performance and heat retention performance, it can be applied to a heating element in a place where the atmospheric environment is severe, for example, a heating element mounted on an automobile. The performance of a heating element, such as a transmission, mounted on an automobile decreases when its temperature falls below a predetermined temperature. Therefore, when the vehicle is started in winter, warm-up operation that increases the temperature of the transmission is required for a certain period of time. By applying the cooling device 10 to the transmission, it is possible to efficiently cool the transmission when the heat is generated, and when the heat is not generated, the temperature at that time can be maintained, that is, the temperature can be maintained. Therefore, it is possible to suppress the temperature drop of the transmission due to the atmospheric temperature in winter and to shorten the warm-up operation time when starting the vehicle. Further, according to the cooling device 10 of the present invention, the chamber 28 can be easily formed by the container 30 between the evaporator 14 and the transmission even in a complicated shape such as a transmission. The heating element mounted on the automobile is not limited to the transmission, and may be a battery that needs to be maintained within a predetermined temperature range.

  In this embodiment, the case where the thermo element 34 drives the valve body 36 according to the temperature of the heating element 12 and the valve 26 opens and closes the liquid flow path 24 has been described. However, the present invention is not limited to this configuration. . A temperature sensor that detects the temperature of the heating element 12 may be provided in the heating element 12, and an actuator may drive the valve body 36 according to the detection result, and the valve 26 may open and close the liquid flow path 24.

It is a figure which shows the structure of the cooling device which concerns on this embodiment. It is sectional drawing which shows the structure of the valve | bulb of a closed state. It is sectional drawing which shows the structure of the valve | bulb of an open state. It is a figure which shows the mode of a time change of a heat generating body temperature and a condenser temperature when a refrigerant | coolant pressure is atmospheric pressure. It is a figure which shows the mode of a time change of a heat generating body temperature and a condenser temperature, when refrigerant pressure is pressure-reduced. It is a figure which shows the shape of a vacuum hollow particle. It is a figure which shows an example of the outer peripheral surface of a heat generating body, and the vacuum hollow particle arranged in this. It is a figure which shows an example of the outer peripheral surface of a heat generating body, and the vacuum hollow particle arranged in this.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Cooling device, 12 Heating element, 14 Evaporator, 16 Condenser, 18 Tank, 20 Circulation path, 22 Gas flow path, 24 Liquid flow path, 26 Valve, 28 Chamber, 30 Container, 32 Vacuum hollow particle.

Claims (5)

An evaporator that stores the refrigerant, heats the refrigerant by a heating element, and evaporates;
A condenser for condensing the evaporated refrigerant;
A circulation path for connecting the evaporator and the condenser and circulating the refrigerant;
A cooling device comprising:
The evaporator is
A container that forms a chamber for storing the refrigerant between the heating element and
Vacuum hollow particles with an internal vacuum held in the chamber;
Including
A cooling device, wherein the refrigerant flows through a gap between the vacuum hollow particles. The cooling device according to claim 1,
The circuit is
A liquid flow path through which refrigerant condensed from the condenser to the evaporator flows;
A valve for opening and closing the liquid flow path;
Including
The cooling device, wherein the valve is closed when the temperature of the heating element is equal to or lower than a predetermined value. The cooling device according to claim 1 or 2,
Each of the vacuum hollow particles is arranged to be in point contact or line contact with the heating element and the adjacent vacuum hollow particles. The cooling device according to any one of claims 1 to 3,
The cooling device according to claim 1, wherein the container of the evaporator is formed of a flexible film. The cooling device according to any one of claims 1 to 4,
The cooling device, wherein the refrigerant sealed in the cooling device is decompressed.

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