JP3876504B2 - Boiling cooler - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thermosiphon-type boiling cooling apparatus.
[0002]
[Prior art]
When a heating element such as an electronic component is housed in a sealed housing, it cannot be ventilated by directly taking outside air into the housing. Therefore, the present applicant has filed a boiling cooling device that performs heat exchange between the air inside the housing and the air outside the housing as means for cooling the heating element housed in the housing (Japanese Patent Application No. 8- No. 250870). This boiling cooling device is formed by connecting a high-temperature side heat exchanger arranged inside a housing and a low-temperature side heat exchanger arranged outside the housing in a ring shape by a connecting pipe, and the connecting pipe and each heat exchanger are attached and detached. The assemblability is improved by using a structure that can be fastened.
[0003]
[Problems to be solved by the invention]
However, when the connecting tube and each heat exchanger can be detachably fastened as described above, the fitting portion is generally formed by sealing the fitting portion between the connecting tube and the heat exchanger with an O-ring or the like. The refrigerant leaks from the air, but cannot be completely prevented, so the refrigerant leaks during long-term use. In particular, when a chlorofluorocarbon refrigerant such as HFC134a is used as the refrigerant, the internal pressure increases, so that a large amount of refrigerant leaks during long-term use. As a result, the amount of refrigerant enclosed in the device is reduced and the liquid level in the high-temperature side heat exchanger storing the liquid refrigerant is lowered, so the heat absorption amount of the high-temperature side heat exchanger is reduced and heat is dissipated. The problem is that the performance is degraded.
The present invention has been made based on the above circumstances, and an object of the present invention is to provide a boiling cooling device capable of suppressing a decrease in heat dissipation performance due to refrigerant leakage accompanying long-term use.
[0004]
[Means for Solving the Problems]
(Means of Claim 1)
The boiling cooling device according to claim 1 is a boiling cooling device for cooling a heating element housed in a housing, and a plurality of tubes arranged in parallel in a vertical direction, and both ends of each tube Connected to each tube and having an upper tank and a lower tank arranged in the horizontal direction, and arranged inside the housing, for exchanging heat between the refrigerant flowing inside and the high-temperature fluid inside the housing. A high temperature side heat exchanger to be performed, a plurality of tubes arranged in parallel in the vertical direction, and an upper tank and a lower tank connected to both ends of each tube and communicating with each tube and arranged in the horizontal direction A low-temperature side heat exchanger that is arranged outside the housing and higher than the high-temperature side heat exchanger and exchanges heat between the refrigerant flowing inside and the low-temperature fluid outside the housing, and one end of the high-temperature side heat exchange Connected to the top of the heat exchanger, the other end is the low temperature side heat exchanger A steam inlet pipe connected to the upper part for introducing the boiling refrigerant boiled in the high temperature side heat exchanger into the low temperature side heat exchanger, one end connected to the lower part of the low temperature side heat exchanger, and the other end to the high temperature side heat exchange And a liquid introduction pipe connected to the lower part of the vessel for introducing the liquid refrigerant liquefied by the low temperature side heat exchanger into the high temperature side heat exchanger.
The steam introduction pipe and the liquid introduction pipe constitute a connecting pipe that connects the high temperature side heat exchanger and the low temperature side heat exchanger in an annular shape, and this connecting pipe is a pipe capable of storing a predetermined amount of preliminary refrigerant. It has a length. Thereby, even if refrigerant leakage occurs during long-term use, the required heat dissipation performance can be maintained until there is no reserve refrigerant amount stored in the connecting pipe.
The liquid inlet pipe, lateral pipe, which is substantially the pipe extends horizontally or oblique direction of the space formed between the upper tank and the lower tank low-temperature heat exchanger of the high-temperature side heat exchanger in a vertical direction Has a part. By providing this horizontal pipe portion, a predetermined amount of preliminary refrigerant can be stored.
Furthermore, the pressure loss of the flow path can be reduced by providing the horizontal pipe portion in the liquid introduction pipe than in the case of providing the horizontal pipe section in the steam introduction pipe. That is, the pressure loss of the flow path is larger in the vapor introduction pipe through which the gas-phase refrigerant flows than in the liquid introduction pipe through which the liquid-phase refrigerant flows. Therefore, the horizontal pipe portion for storing the spare refrigerant is provided in the liquid introduction pipe. Is advantageous in terms of pressure loss of the flow path.
[0006]
(Means of Claim 2 )
The horizontal piping part has a curved pipe part in which the refrigerant flows in a curve. That is, the horizontal piping portion does not necessarily have to be linearly piped, and the refrigerant may be configured to flow in a curved manner (for example, meandering shape, spiral shape).
[0007]
(Means of claim 3 )
The connecting pipe has a pipe length that is 1.5 times or more the shortest pipe length necessary for connecting the low temperature side heat exchanger and the high temperature side heat exchanger. Thereby, the amount of refrigerant leakage during long-term use (for example, 20 years) can be compensated. Even if it is shorter than 1.5 times, it is possible to store the amount of reserve refrigerant as long as it is longer than the shortest pipe length, but it is desirable that it is 1.5 times or more in consideration of long-term use.
[0010]
(Means of claim 4 )
The connecting pipe is detachably connected to the low temperature side heat exchanger and the high temperature side heat exchanger. In this case, although the assembly work of the connecting pipe to the heat exchanger can be facilitated, it is difficult to completely prevent the refrigerant from leaking from the connecting portion, so that the refrigerant may leak due to long-term use. On the other hand, by adopting any one of the means described in claims 1 to 3 , refrigerant leakage can be compensated for by the amount of spare refrigerant stored in the connecting pipe, and desired heat dissipation performance can be maintained. . Thereby, the merit which can perform the assembly | attachment operation | work of a connecting pipe easily can be acquired, without causing the fall of the thermal radiation performance by a refrigerant | coolant leak.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a front view of the boiling cooling device 1.
The boiling cooling device 1 of the present embodiment is disposed outside a housing 3 (a high-temperature side heat exchanger according to the present invention) disposed inside a sealed housing 2 (see FIG. 2). A condenser 4 (low temperature side heat exchanger of the present invention), a connecting pipe (steam introduction pipe 5 and liquid introduction pipe 6) for connecting the boiling machine 3 and the condenser 4, and an indoor fan 7 for blowing air to the boiling machine 3 And an outdoor fan 8 that blows air to the condenser 4, and a predetermined amount of refrigerant (for example, a chlorofluorocarbon refrigerant such as HFC134a) in a sealed space formed by the boiler 3, the condenser 4, and the connecting pipes 5 and 6. Is enclosed.
The housing 2 is used, for example, in a radio base station of a mobile radio telephone such as a mobile phone or a car phone, and accommodates a communication device (not shown) as a heating element inside.
[0012]
The boiling device 3 includes a plurality of tubes 9 arranged in parallel, a pair of tanks (upper tank 10 and lower tank 11) connected to both ends of each tube 9 and communicating with each other. The heat receiving fins 12 are interposed between the matching tubes 9 and are joined by integral brazing.
The tube 9 is formed in an oval shape with a flat cross-sectional shape by a metal material (for example, aluminum or copper) having excellent heat conductivity.
Each of the tanks 10 and 11 is formed in a substantially cylindrical shape with both ends closed by the same metal material as that of the tube 9, and the end of each tube 9 is inserted at a certain interval in the longitudinal direction (left and right direction in FIG. 1). Has been. The upper tank 10 is provided with a connection port (not shown) for connecting the steam introduction pipe 5 to one end portion in the longitudinal direction (right end portion in FIG. 1), and the lower tank 11 has a liquid port at the other end portion in the longitudinal direction. A connection port (not shown) for connecting the introduction pipe 6 is provided.
The heat receiving fins 12 are formed, for example, by bending aluminum thin plates alternately into a wave shape, and are joined to the surface of the tube 9 at each bent portion.
As shown in FIG. 2, the boiling device 3 is attached in a posture inclined by a predetermined angle with respect to the standing wall surface 2 a of the housing 2.
[0013]
The condenser 4 includes a plurality of tubes 13 arranged in parallel, a pair of tanks (an upper tank 14 and a lower tank 15) connected to both ends of each tube 13 and communicating with each other. It is comprised from the fin 16 for heat dissipation interposed between each tube 13 which fits, and is joined by integral brazing.
The tube 13 is formed in an oval shape with a flat cross-sectional shape using a metal material (for example, aluminum or copper) having excellent heat conductivity.
Each tank 14 and 15 is formed in the substantially cylindrical shape which both ends closed with the same metal material as the tube 13, and the edge part of each tube 13 is inserted in the longitudinal direction at fixed intervals. The upper tank 14 is provided with a connection port (not shown) for connecting the steam introduction pipe 5 to the other end portion in the longitudinal direction (left end portion in FIG. 1), and the lower tank 15 has liquid at one end portion in the longitudinal direction. A connection port (not shown) for connecting the introduction pipe 6 is provided.
The heat radiation fins 16 are formed, for example, by bending aluminum thin plates alternately into a wave shape, and are joined to the surface of the tube 13 at each bent portion.
As shown in FIG. 2, the condenser 4 is disposed at a position higher than the boiling unit 3 in the vertical direction, and is inclined at a predetermined angle with respect to the standing wall 2 a of the housing 2 toward the opposite side of the boiling unit 3. It is attached.
[0014]
The connection pipes 5 and 6 are used, for example, by cutting a metal pipe such as aluminum into a predetermined length, and a steam introduction pipe 5 for introducing the boiling refrigerant boiled in the boiler 3 into the condenser 4; A liquid introduction pipe 6 for introducing the liquid refrigerant liquefied by the condenser 4 into the boiling device 3 is provided through a through hole 2 b formed in the standing wall surface 2 a of the housing 2. The through hole 2b is hermetically closed by the unions 17, 18 and the like brazed to the introduction pipes 5 and 6 (see FIG. 2).
As shown in FIG. 1, the steam introduction pipe 5 has one end detachably connected to a connection port provided in the upper tank 10 of the boiling device 3 via a joint member 19, and the other end connected to the upper tank of the condenser 4. 14 is detachably coupled to a connection port provided in 14 via a joint member 20. The steam introduction pipe 5 includes a horizontal pipe portion 5 a that is piped in a substantially horizontal direction between the upper tank 10 of the boiling unit 3 and the lower tank 15 of the condenser 4, and the other end side of the condenser 4 that is connected to the condenser 4. And a vertical pipe portion 5b that is piped while being inclined substantially in parallel. As shown in FIG. 1, the liquid introduction pipe 6 has one end detachably connected to a connection port provided in the lower tank 15 of the condenser 4 via a joint member 21, and the other end connected to the lower tank of the boiling device 3. 11 is detachably coupled to a connection port provided in 11 via a joint member 22. The liquid introduction pipe 6 includes a horizontal pipe portion 6 a that is piped in a substantially horizontal direction between the upper tank 10 of the boiling machine 3 and the lower tank 15 of the condenser 4, and the other end side of the boiling machine 3. And a vertical piping part 6b that is inclined substantially parallel to the pipe.
[0015]
The indoor fan 7 is, for example, an axial flow fan, and a plurality of the indoor fans 7 are attached to the upper portion of the boiling device 3, and blows the air inside the housing 2 (high temperature by the heat generated by the heating element) to the boiling device 3.
The outdoor fan 8 is, for example, a larger axial flow fan than the indoor fan 7 and is attached to the upper part of the condenser 4, and blows air outside the housing 2 (that is, outside air) to the condenser 4. As shown in FIG. 2, the outdoor fan 8 is accommodated in the casing 23 together with the condenser 4, and is fixed to the standing wall surface 2 a of the housing 2 through the casing 23.
The indoor fan 7 and the outdoor fan 8 are energized and controlled by a controller (not shown) based on the internal temperature of the housing 2 detected by a temperature sensor (not shown) such as a thermistor.
In addition, the refrigerant | coolant liquid level inside an apparatus is set in the position a little lower than the lower tank 15 of the condenser 4, for example. That is, the liquid refrigerant is filled up to the horizontal piping part 5 a of the steam introduction pipe 5 and the horizontal piping part 6 a of the liquid introduction pipe 6.
[0016]
Next, the operation of this embodiment will be described.
When the internal temperature of the housing 2 rises due to the heat generated from the heating element and the indoor fan 7 and the outdoor fan 8 are energized through the controller, the internal air of the housing 2 is blown to the boiling device 3 by the indoor fan 7, and the outdoor fan The outside air is sent to the condenser 4 by 8. Thereby, in the boiling device 3, the liquid refrigerant with which each tube 9 is filled receives heat from high temperature air, and boils. The boiling refrigerant (boiling refrigerant) rises in each tube 9 of the boiling device 3 and flows from the upper tank 10 through the vapor introduction tube 5 to the upper tank 14 of the condenser 4. In the condenser 4, when the boiling refrigerant distributed from the upper tank 14 to each tube 13 flows through each tube 13, it is cooled by receiving air from the outdoor fan 8, releases latent heat, and condenses on the wall surface of the tube 13. The condensed refrigerant is dropped into the lower tank 15 of the condenser 4 as droplets. The condensate accumulated in the lower tank 15 flows into the lower tank 11 of the boiling device 3 through the liquid introduction pipe 6 and is supplied again from the lower tank 11 to each tube 9 of the boiling device 3 to repeat the above cycle.
As described above, the refrigerant repeatedly boils and condenses and circulates in the boiling device 3 and the condenser 4, so that the heat generated from the heating element is sequentially released to the outside air, and the temperature rise of the heating element is suppressed. The
[0017]
(Effects of the first embodiment)
In this embodiment, since the horizontal pipe part 5a and the vertical pipe part 5b are provided in the steam introduction pipe 5, the upper tank 10 of the boiling device 3 and the upper tank 14 of the condenser 4 are connected in the shortest distance. The total length of the steam introduction pipe 5 can be set longer than the pipe length (at least 1.5 times or more). Similarly, since the liquid piping 6 is provided with the horizontal piping 6a and the vertical piping 6b, the piping length when the lower tank 15 of the condenser 4 and the lower tank 11 of the boiling device 3 are connected at the shortest distance. Thus, the total length of the liquid introduction pipe 6 can be set longer (at least 1.5 times or more). As a result, a predetermined amount of reserve refrigerant can be stored in the vapor introduction pipe 5 and the liquid introduction pipe 6, so even if refrigerant leakage occurs during long-term use, the reserve refrigerant stored in each of the introduction pipes 5 and 6. The required heat dissipation performance can be maintained until the amount disappears.
[0018]
Compared to the case where the upper tank 10 of the boiling unit 3, the upper tank 14 of the condenser 4, the lower tank 15 of the condenser 4 and the lower tank 11 of the boiling unit 3 are connected at the shortest distance (conventional boiling cooling device). As shown in FIG. 3, the present embodiment can increase the amount of reserve refrigerant stored in the connecting pipes 5 and 6, so that the required heat dissipation performance can be maintained even if refrigerant leakage occurs due to long-term use. Therefore, it is possible to secure a longer time to decrease to the minimum refrigerant amount (about 430 g in FIG. 3). That is, it is possible to maintain the heat dissipation performance required for a longer period than the conventional device.
Further, in this embodiment, the horizontal pipe portions 5a and 6a are provided in the steam introduction pipe 5 and the liquid introduction pipe 6 in order to store a predetermined amount of preliminary refrigerant, respectively. Since the pipes are connected between the upper tank 10 and the lower tank 15 of the condenser 4, even if the lengths of the introduction pipes 5 and 6 are increased, the entire apparatus is not enlarged.
[0019]
(Second embodiment)
FIG. 4 is a front view of the boiling cooling device 1.
This embodiment shows another example of the liquid introduction pipe 6. As shown in FIG. 4, the horizontal piping section 6a of the liquid introduction pipe 6 is divided into an upper tank 10 of the boiling unit 3 and a lower tank 15 of the condenser 4. To the left and right. In this case, since a larger amount of reserve refrigerant can be secured as compared with the first embodiment, it is possible to maintain the heat dissipation performance required over a longer period of use. Note that not only the liquid introduction pipe 6 but also the horizontal pipe portion 5a of the steam introduction pipe 5 may be reciprocated.
[0020]
(Modification)
In the above embodiment, the horizontal piping portion 5a of the steam introduction pipe 5 and the horizontal piping portion 6a of the liquid introduction pipe 6 are arranged in a substantially straight line. For example, as shown in FIGS. You may provide the curved pipe part 24 in the piping parts 5a and 6a. Further, the curved pipe portion 24 may be provided in the vertical piping portion 5 b of the steam introduction pipe 5 and the vertical piping portion 6 b of the liquid introduction pipe 6. However, the pressure loss of the flow path is larger in the vapor introduction pipe 5 through which the gas-phase refrigerant passes than in the liquid introduction pipe 6 through which the liquid-phase refrigerant passes. The provision of the liquid introduction pipe 6 in the introduction pipe 5 can reduce the total pressure loss of the flow path and improve the heat dissipation performance.
In the present embodiment, the example in which the steam introduction pipe 5 and the liquid introduction pipe 6 are detachably connected to the boiler 3 and the condenser 4 via the joint members 19 to 22 has been described. May be joined.
[Brief description of the drawings]
FIG. 1 is a front view of a boiling cooling device (first embodiment).
FIG. 2 is a side view of the boiling cooling device (first embodiment).
FIG. 3 is a graph showing the relationship between the amount of refrigerant and heat dissipation performance.
FIG. 4 is a front view of a boiling cooling device (second embodiment).
FIG. 5 is a plan view showing a curved tube portion (modified example).
FIG. 6 is a plan view showing a curved tube portion (modified example).
[Explanation of symbols]
1 Boiling cooler 2 Housing (housing)
3 Boiler (High temperature side heat exchanger)
4 Condenser (low temperature side heat exchanger)
5 Steam introduction pipe (connecting pipe)
5a Horizontal piping part 6 Liquid introduction pipe (connecting pipe)
24 Curved pipe

Claims (4)

A boiling cooling device for cooling a heating element housed in a housing,
A plurality of tubes arranged in parallel in the vertical direction, and an upper tank and a lower tank connected to both ends of each tube and communicating with each tube and arranged in the horizontal direction, A high temperature side heat exchanger that exchanges heat between the refrigerant flowing inside and the high temperature fluid inside the housing;
A plurality of tubes arranged in parallel in a vertical direction, and connected to both ends of each tube, communicated with each tube, and horizontally arranged in an upper tank and a lower tank, A low temperature side heat exchanger that is arranged at a position higher than the high temperature side heat exchanger and performs heat exchange between the refrigerant flowing inside and the low temperature fluid outside the housing;
One end is connected to the upper part of the high temperature side heat exchanger, the other end is connected to the upper part of the low temperature side heat exchanger, and the boiling refrigerant boiled in the high temperature side heat exchanger is introduced into the low temperature side heat exchanger. A steam inlet pipe to perform,
One end is connected to the lower part of the low temperature side heat exchanger, the other end is connected to the lower part of the high temperature side heat exchanger, and the liquid refrigerant liquefied by the low temperature side heat exchanger is introduced into the high temperature side heat exchanger And a liquid introduction pipe that
The steam introduction pipe and the liquid introduction pipe constitute a connection pipe that connects the high temperature side heat exchanger and the low temperature side heat exchanger in an annular shape, and the connection pipe stores a predetermined amount of preliminary refrigerant. The liquid introduction pipe has a space formed between the upper tank of the high temperature side heat exchanger and the lower tank of the low temperature side heat exchanger in the vertical direction. A boiling cooling device having a horizontal piping part that extends in a horizontal direction or an oblique direction. The transverse pipe section, cooling apparatus according to claim 1, characterized in that the coolant has a curved tube portion flowing curve. The connecting pipe has a pipe length of 1.5 times or more of a shortest pipe length necessary for connecting the low temperature side heat exchanger and the high temperature side heat exchanger. boiling Teng cooling device according to claim 1 or 2. The boiling cooling device according to any one of claims 1 to 3 , wherein the connecting pipe is detachably connected to the low temperature side heat exchanger and the high temperature side heat exchanger.

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