JPH0682181A - Heat pipe type conduit cooling apparatus - Google Patents

Abstract

PURPOSE:To provide a small-sized cooling apparatus capable of uniform cooling the inside of a conduit passage for electric power transmission over a long distance of the same. CONSTITUTION:A heat pipe 10 absorbs heat in a conduit passage 2, so that a title apparatus is made small-sized and there is ensured uniform heat absorption longitudinally of the cavity passage 2. Further, a looped heat pipe is employed, so that there are prevented a working fluid liquefied in a condensation section 12 and flown back toward an evaporation tube 11 and a vapor stream of the working fluid moving from the evaporation tube 11 to the condensation part 12 from interferring to each other to ensure long distance reflux flow and hence a sufficient amount of the working fluid is supplied to the evaporation tube 11. Additionally, a circulation pump 20 is used for movement of the working fluid to the evaporation tube 11 for forced circulation of the working fluid, so that even further long distance reflux of the working fluid is facilitated. Thus, cooling in the conduit passage 2 over a long distance is ensured using the present heat pipe 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pipe type tunnel cooling device for cooling the inside of a cave for laying an underground power transmission cable.

[0002]

2. Description of the Related Art When a large number of power transmission cables are laid in an underground cavern, the temperature inside the cavern increases due to heat radiated from each cable, and the cable temperature also rises. If the temperature inside the cave becomes too high, the transmission capacity of the cable will be limited. Therefore, it is necessary to install a cooling device in the cave to keep the temperature in the cave within an allowable value.

3 and 4 show an example of a cooling device which mainly absorbs heat in the disaster prevention trough by cooling water when a power transmission cable is laid in the cave through a disaster prevention trough. That is, in this cooling device 100, a water cooling pipe 101 to which cooling water is supplied is installed in a disaster prevention trough 3 to which a power transmission cable 4 is attached, and a return pipe 102 is installed in a cave 2 outside the disaster prevention trough 3. The circulation pump 103 and the refrigerator 104 are installed at predetermined locations, and the cooling water cooled by the refrigerator 104 is circulated through the polyethylene cold water pipe 101 and the return pipe 102 by the circulation pump 103. It absorbs heat from the disaster prevention trough 3.

The cooling device 100 mainly absorbs heat in the disaster prevention trough 3, but the disaster prevention trough 3 itself is installed in the cave 2.
Considering the entire cave 2, the cooling device 100 can be considered as a cooling device in the cave 2 that absorbs heat from the cave 2.

[0005]

However, in the device that absorbs heat from the inside of the cave 2 by circulating the cooling water as described above, since only the sensible heat of the water can be absorbed, the temperature rise of the cooling water is large. The cooling distance L with the cooling water could not be increased. Therefore, it is necessary to install the circulation pumps 103 and the refrigerators 104 at a plurality of places between the substations where the stile 2 is provided, which causes a cost increase. Especially in urban areas, circulation pump 103 and refrigerator 104
It is difficult to secure a site for the adjustment station where the
Was desired.

It is also conceivable to increase the flow rate of the cooling water to suppress the temperature rise of the cooling water as much as possible, and to lengthen the cooling distance L. However, by this, the circulation pump 103, the refrigerator 104, the water cooling pipe 101 and the return path. In addition to increasing the size and cost of the pipe 102, the cave 2 and the disaster prevention trough 3
However, there is a problem in that the size and cost of the device increase. Further, since there is a large temperature difference between the cooling water at the inlet and outlet of the water cooling pipe 101, there is a problem that the inside of the cave 2 (in this case, the disaster prevention trough 3 in particular) cannot be cooled uniformly.

Although it can be cooled by a heat pipe, if the length of a normal heat pipe is lengthened, the vapor flow from the evaporation part to the condensation part of the heat pipe and the flow of the working fluid from the condensation part to the evaporation part. Therefore, there is a problem in that the working fluid is prevented from flowing back, the amount of the working fluid supplied to the evaporation portion is insufficient, a dryout phenomenon occurs, and the cooling capacity easily becomes unstable.

The present invention has been made in view of the above problems, and provides a small-sized and low-cost cooling device capable of uniformly and efficiently cooling a cave for laying a power transmission cable over a long distance. With the goal.

[0009]

Means for Solving the Problems As a means for solving the above problems, the present invention relates to a cavern cooling device for cooling the inside of a cavern with an underground power transmission cable installed, in which the power transmission cable is installed in parallel with the installation direction. An evaporator is provided in the cave, a condenser is provided at one end of the evaporator, and a liquid return pipe that connects the condenser and the other end of the evaporator is provided to form a loop. A condensable working fluid is enclosed in the interior of the liquid pipe to form a heat pipe, a circulation pump is provided near the condensation part of the liquid return pipe, and a cooling means is disposed close to the outside of the condensation part. It has a feature.

[0010]

As means for absorbing heat from the inside of the cave, the evaporating portion of the heat pipe formed in a loop shape by connecting the condensing portion side at one end of the evaporating portion and the other end side of the evaporating portion are connected by a liquid return pipe. Since the power transmission cable is arranged in the cave so as to be parallel to the installation direction of the power transmission cable, the heat generated from the power transmission cable heats the evaporation portion. The working fluid that has boiled into vapor in the evaporation unit moves to the low-temperature low-pressure condensation unit, radiates heat in the condensation unit, is condensed, and returns to the liquid-phase working fluid. At this time, since the condenser is provided with the cooling means, a large amount of vapor is condensed and a large amount of heat can be released.

The working fluid that has returned to the liquid phase in the condenser section is sent to the evaporation section in the liquid return tube for reflux by a circulation pump provided near the condenser section of the liquid return tube. Therefore, since the working fluid is forcedly circulated by providing the circulation pump, heat can be transported over a long distance in the longitudinal direction of the sinus, and as a result, the inside of the long sinus is uniformly cooled.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of the inside of a cave 2 for power transmission formed in the ground, and 3 in the figure is a disaster prevention trough provided in the cave 2 and made of concrete, for example. The disaster prevention trough 3 is supported at a predetermined position in the cave 2 by a support means (not shown), and a plurality of high-voltage (for example, tens to hundreds of KV) power transmission cables 4 are laid inside. In addition, a plurality of low-voltage (for example, several KV) power transmission cables 6 are laid on the support 5 in the cave 2 outside the disaster prevention trough 3.

Reference numeral 1 in FIG. 1 directly absorbs heat from the inside of the cave 2 and also absorbs heat from the disaster prevention trough 3 to directly or indirectly extend a long cave for several kilometers. It is a heat pipe type cooling device capable of cooling the inside of 2 at once. This heat pipe type cooling device 1 includes a plurality of long evaporating pipes 11, a header pipe 11a for converging one end side of the plurality of evaporating pipes 11, a relatively short condensing portion 12, and a header pipe 11b. A loop type heat pipe 10 composed of a condenser 12 and a liquid return pipe 15 connecting the end of the evaporation pipe 11, a circulation pump 20 for forcibly circulating the working fluid in the heat pipe 10, and a heat It comprises a refrigerator 30 for cooling the condenser 12 of the pipe 10.

The heat pipe 10 has, for example, a vacuum degassed corrugated pipe filled with a fluid such as CFC or alcohol which evaporates and condenses in a target temperature range as a working fluid.
After the working fluid is evaporated in the high temperature side evaporation tube 11, it is condensed in the low temperature side condensation section 12, and heat is transferred from the evaporation tube 11 side to the condensation section 12 side by the transfer of latent heat of the working fluid. Is. In this embodiment, the closed pipe (container pipe) is a corrugated pipe.
Here, in general, the working fluid is circulated in the closed tube by using gravity or capillary force without any external work, but as in this embodiment, a long cooling path for a long cavern 2 extending for several kilometers is used. As a lengthy heat pipe 10,
As described above, since it is difficult to circulate the working fluid in the normal straight pipe type heat pipe, the heat pipe 1 is used in this embodiment.
0 is a loop type, and the circulation pump 20 circulates the working fluid, that is, forcibly recirculates the working fluid.

In the heat pipe 10, a two-phase working fluid of vapor and liquid flows, and an evaporation pipe 11 for heating the working fluid and a working fluid liquefied in the condenser 12 are evaporated in the pipe 1.
After being divided into a plurality of (two in this case) branch pipes via the liquid return pipe 15 for returning to the other end side of 1 and the header pipe 11a,
It is installed in the upper part of the disaster prevention trough 3. Then, the branch pipes of the evaporation pipe 11 that have exited from the disaster prevention trough are reassembled into a steam pipe 11c via the header pipe 11e, and are connected to the condenser unit 12.

The condensing part 12, the circulation pump 20, and the refrigerator 30 of the heat pipe 10 are installed outside the cavern 2 or in a regulation station where a part of the cavern 2 is widened. The working fluid in the vapor phase, which has been moved from the condenser section 12 to the condenser section 12, is cooled and condensed by the refrigerator 30 in the condenser section 12, returned to the liquid phase, and supplied to the circulation pump 20. The output of the circulation pump 20 is the heat pipe 1
It is determined in consideration of the pressure loss of the working fluid within zero.

The refrigerator 30 is the same as an ordinary commercial product, and is an existing one including an evaporator 31, a condenser 32, an expansion valve 33, a compressor 34, etc., and a working fluid such as ammonia is compressed by the compressor 34. After being adiabatically compressed by the condenser 32, it is cooled and liquefied by the condenser 32, and this is adiabatically expanded by the expansion valve 33 and evaporated 31
The heat is taken from the object to be cooled by the evaporator 31 by passing the heat through it. In this case, the condenser 12 of the heat pipe 10 may be directly cooled by the evaporator 31, or the medium 3 may be cooled as shown in FIG.
It may be indirectly cooled by the evaporator 31 via 5.

Next, the operation of the heat pipe type cooling device 1 will be described. The inside of the cave 2 is heated by heat radiation from the low-capacity low-voltage cable 6, and the inside of the disaster prevention trough 3 provided in the cave 2 is heated by heat radiation from the high-capacity high-voltage cable 4. Since the cave 2 is provided in the ground, the amount of heat released from the cave 2 to the outside is small and the temperature inside the cave 2 including the disaster prevention trough 3 tends to rise. On the other hand, when the circulation pump 20 and the refrigerator 30 of the heat pipe type cooling device 1 are operated in this state,
As shown in FIG. 2, the working fluid in the heat pipe 10 is in a two-phase state of a gas phase and a liquid phase, and the working fluid absorbs heat in the cave 2 and the disaster prevention trough 3, and the heat is condensed in the condensing section. 12
In order to move it to the refrigerator 30 side, the temperature inside the cave 2 and the disaster prevention trough 3 is maintained at a constant value.

That is, a large amount of heat from the high-voltage cable 4 discharged into the disaster prevention trough 3 evaporates the working fluid in the evaporation pipe 11 of the heat pipe 10 and is absorbed by the working fluid in the form of latent heat. A relatively small amount of heat from the low-voltage cable 6 directly released into the sinus 2 raises the temperature of the working fluid in the liquid pipe portion 11a of the evaporation pipe 11 of the heat pipe 10, and is absorbed by the working fluid in the form of sensible heat. To be done. Then, the vapor of the working fluid that has absorbed the heat in the form of latent heat and sensible heat moves to the low temperature and low pressure side of the condensing unit 12, and in the condensing unit 12, the refrigerator 30
The liquid is cooled and condensed by the liquid to return to the liquid-phase working fluid, and the circulation pump 20 causes the liquid return pipe 15 to pass through the evaporation pipe 1
It is sent to the header pipe 11a following 1 and is returned to the inside of the evaporation pipe 11 to absorb heat from the inside of the sinus 2 again.

As described above, the heat generated directly in the cave 2
Since the heat pipe indirectly absorbs the heat generated in the tunnel 2 through the disaster prevention trough 3, the latent heat of the working fluid is mainly absorbed by the heat pipe.
A large amount of heat can be transported compared to the circulation method of cooling water that absorbs heat from the inside, and this device can reduce the size of pumps and pipes and reduce the cost, and further, it can be used for caverns 2 and disaster prevention. The trough 3 can be downsized. In addition, this device uses latent heat to uniformly absorb heat from the inside of the cave 2 because the temperature difference between the working fluids is less likely to occur.
The inside can be maintained at a uniform temperature along its length. Furthermore, this device can extend the cooling distance in the cave 2 due to the large amount of heat absorbed by the use of latent heat, and the use of a long heat pipe having a total length of several kilometers by means of the circulating pump 20 provided. Therefore, it is possible to increase the interval between the cooling means such as the refrigerator 30 and the circulation pump in the cave (or above-ground portion). Further, since the condenser 30 is provided with the refrigerator 30 and the liquid return pipe 15 is provided with the circulation pump 20, it is possible to achieve downsizing and cost reduction of the apparatus.

Further, in this apparatus, since the corrugated pipe is used as the closed pipe of the heat pipe 10 and the heat receiving area is made larger than that of a general straight pipe, the heat pipe 10
A sufficient amount of heat absorption to the side can be secured, and the temperature of the working fluid in the evaporation pipe 11 of the heat pipe 10 can be raised by that amount, and the coefficient of performance of the refrigerator 30 can be raised.

In the above embodiment, the case where the disaster prevention trough 3 for the high voltage cable 4 is installed in the cave 2 has been described, but the disaster prevention trough 3 is not provided and the high voltage cable 4 is directly provided.
Needless to say, it may be provided in the cave 2 and a plurality of disaster prevention troughs 3 may be provided in the cave 2. However, when a plurality of disaster prevention troughs 3 are provided in the cave 2, it is necessary to install the evaporation pipe 11 of the heat pipe 10 in each disaster prevention trough 3.

[0023]

As is apparent from the above description, according to the present invention, as a means for absorbing heat from the inside of the cave, the condensing part side at one end of the evaporating part and the other end side of the evaporating part are connected by a liquid return pipe. The evaporation part of the heat pipe that is connected and formed in a loop is arranged in the cave so as to be parallel to the laying direction of the power transmission cable, and a large amount of steam is generated because the cooling part is provided in the condensation part. It has a high heat transfer capacity because it can be condensed and released a large amount of heat, and a working fluid is forcedly circulated through a circulation pump in the liquid return pipe, so heat transfer over a long distance in the longitudinal direction of the cave. As a result, it is possible to uniformly cool a long cave.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a state change of a working fluid in a heat pipe.

FIG. 3 is an explanatory diagram of a conventional technique.

FIG. 4 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

10 ... Heat pipe, 11 ... Evaporation pipe, 12 ... Condensing part, 15 ... Liquid return pipe, 20 ... Circulation pump, 30 ... Refrigerator (cooling means).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Masuko 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric Wire Co., Ltd. (72) Inventor Masahiko Ito 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric wire company (72) Inventor Yuuji Saito 1-5-1 Kiba, Koto-ku, Tokyo Fujikura Electric Line Co., Ltd. (72) Inventor Fumiaki Aoyama 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric line Within the corporation

Claims (1)

[Claims] 1. A cavern cooling device for cooling the inside of a cavern where an underground power transmission cable is laid, wherein an evaporating portion is arranged in the cavern parallel to a laying direction of the electric power transmitting cable, and one end side of the vaporizing part is provided. And a liquid return pipe that connects the condensing part and the other end of the evaporating part to each other to form a loop, and a condensable working fluid is enclosed in the inside to form a heat pipe. A heat pipe type sinus cooling device characterized in that a circulation pump is provided in the vicinity of the condensing part of the liquid return pipe, and cooling means is arranged in the vicinity of the outside of the condensing part.