JPH09250779A - Cooling system of communication relay station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the height of a communication relay station package so as to facilitate its transportation and installation and cool uniformly the inside of an enclosed booth at the same time in the case when a natural circulation loop, which is designed for energy saving, is used to cool the enclosed booth of a communication relay station package. SOLUTION: An outdoor unit 10 provided with a built-in condenser is laid out on the upper part of a booth 24 while an indoor unit 8 is laid out on the lower part of the booth 4, thereby using the height of the booth 4 as a differential undulation area of a high condenser and a vaporizer. This construction makes it possible to restrain the full height of a communication relay station package to the height of the booth 4. A fan 14 is provided so as to prevent cooled air from remaining since the vaporizer is located in the lower position, thereby agitating the air in the booth 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication relay base station cooling system, and more particularly to an efficient and energy-saving cooling system using a natural circulation loop in a communication relay base station whose size is restricted.

[0002]

2. Description of the Related Art In recent years, mobile communication such as car phones and mobile phones has been remarkably spread. The driving force behind this spread is its convenience, which is being spurred by lower service charges. Convenience largely depends on the size of the service area. In the future, relay base stations will be installed at various locations to expand the service area. Now, it is desirable that this relay base station can be installed at a low cost and in a short construction period. Therefore, recently, a small booth for communication relay base stations was preassembled at the factory and transported by truck or the like.
A method of using a high-rise building such as a building and installing it on the roof or the like is adopted.

Now, this booth houses electronic equipment for communication relay. While electronic devices generate heat themselves,
If the temperature rises, its normal operation cannot be guaranteed.
Moisture and dust also adversely affect electronic devices. Therefore, the booth is hermetically sealed by a heat insulating wall and provided with a cooling device. The heat insulation wall prevents moisture and dust, and also suppresses the inflow of heat from the outside when the temperature is high, such as in summer, and when the sunlight is strong. At the same time, the cooling device pumps out the heat generated by the electronic device from the inside of the booth to the outside. As a result, the operating environment of the electronic device is kept good throughout the year. Here, since the booth is composed of a heat insulating wall, the heat generated by the electronic device is likely to be trapped inside the booth. Therefore, unless the external environment is extremely low, the cooling device must be operated to radiate the heat of the electronic device to the outside. That is, in general, it should be considered that the cooling device is required to be operated yearly or constantly, regardless of whether the environment is cold or hot such as four seasons, day and night.

Conventionally, a booth has been equipped with a cooling device such as a refrigerator or an air conditioner using a vapor compression refrigeration cycle which is widely used. In this vapor compression refrigeration cycle, a compressor is used, and a large cooling capacity can be obtained.

[0005]

However, since the cooling of the booth is necessary throughout the year as described above, the compressor must be operated at all times. Therefore, there are problems that the operating cost of the compressor is high and that the life of the compressor is shortened. Regarding the life of the latter, not only is the problem that the cost of repairing the cooling device is high, but also the problem that the expensive electronic device that is the object to be cooled is damaged when the cooling device fails and the communication system goes down. There was also a problem that it had a great social impact, and it was also a problem that special consideration was required for maintenance to prevent failure of the cooling device. As a method capable of solving or mitigating these various problems, it is conceivable to use a cooling device that employs a natural circulation loop that does not require a compressor, but it has the following problems. In order to uniformly cool the inside of the booth in the air conditioner, it is generally necessary to arrange the evaporator in the upper part inside the booth. However, since the natural circulation loop circulates the refrigerant by utilizing the height difference (about 2 m or more) between the condenser and the evaporator, if the evaporator is arranged above the booth, the condenser becomes higher than the booth. For this reason, the communication relay base station becomes large in a place irrelevant to its original function, which makes it difficult to carry it from the factory, makes installation work difficult, and restricts the installation place.

[0006] The present invention is a cooling system for ensuring stable operation of stored electronic equipment by operating in an energy-saving manner by using a natural circulation loop that does not require a compressor, and is a communication system that is easy to carry and install. An object is to provide a cooling system that realizes a relay base station.

[0007]

A cooling system according to the present invention comprises an evaporator which is attached to a lower inner part of a closed booth and absorbs heat of vaporization when a refrigerant liquid becomes a refrigerant gas from the inside of the closed booth. A condenser attached to the upper outside of the booth to liquefy the refrigerant gas generated in the evaporator and return it to the evaporator as the refrigerant liquid; and a blower for making the air temperature in the closed booth uniform. A natural circulation loop driven by using the height of the closed booth is provided. Further, in the cooling system according to the present invention, the blower is a stirring fan attached to an inner upper portion of the closed booth.

According to the present invention, a refrigerant gas is generated by vaporization of the refrigerant liquid in the evaporator, and the refrigerant gas is cooled in the condenser to generate the refrigerant liquid. Therefore, the refrigerant gas pressure of the condenser becomes lower than that of the evaporator, the refrigerant gas rises from the evaporator to the condenser due to this pressure difference, the refrigerant liquid descends from the condenser to the evaporator by gravity, and the refrigerant naturally circulates. To do. By mounting the evaporator at the bottom of the closed booth and the condenser at the top, the height of the closed booth is used for the height difference between the condenser and the evaporator. That is, the height of the condenser is below the upper end of the closed booth, the communication relay base station is prevented from becoming large, and it is easy to transport and install. Since the evaporator is located at a low position, cold air tends to stay in the lower part of the closed booth, but the blower raises this cool air to the upper part of the closed booth, and conversely lowers the warm air in the upper part of the closed booth to the lower part. The air temperature is uniformized.

[0009]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a side view of a communication relay base station package to which the present invention is applied. An electronic device 6 for relaying mobile telephone communication is housed inside a booth 4 which is hermetically sealed by a heat insulating wall 2. This booth 4
The temperature inside rises due to the heat generated from the electronic device 6 and the heat flowing from the outside through the heat insulating wall 2. When the outside temperature of the electronic device 6 becomes high, it becomes difficult to dissipate the heat generated by itself, and the operation of the electronic device 6 becomes unstable or destroyed. Therefore, booth 4 is equipped with a cooling system. The cooling system of this communication relay base station package is a cooling system of a vapor compression refrigeration cycle that is commonly used in combination with a natural circulation loop, that is, a natural circulation combined cooling system, which is an indoor unit 8 or an outdoor unit. Unit 10 and unit connection pipe 1 for connecting them
2 and a blower 14.

FIG. 2 is a schematic diagram showing the construction of the refrigeration cycle portion of the cooling system, which is composed of the indoor unit 8, the outdoor unit 10, and the unit connection pipe 12 connecting them. First, the structure of the vapor compression refrigeration cycle will be described. The condenser 20 and the compressor 22 used in the vapor compression refrigeration cycle are built in the outdoor unit 10. On the other hand, the evaporator 24 is built in the indoor unit 8.

The compressor 22 is driven by a motor, and has a function of adiabatically compressing the refrigerant gas into an overheated refrigerant gas. The condenser 20 radiates heat from the refrigerant gas generated in the evaporator 24 to the atmosphere and liquefies the refrigerant gas into a refrigerant liquid. The condenser 20 is an air-cooled condenser and a fan 26.
It has. The fan 26 blows air to the outer surface of the refrigerant container 27 and promotes heat radiation from the refrigerant gas generated in the evaporator 24 to the atmosphere, which is an external medium having a temperature lower than this. Condenser 20
The refrigerant liquid generated in 2 is the liquid pipe 2 in the unit connection pipe 12.
It goes down to the indoor unit 8 through 8.

The expansion valve 30 is provided immediately before the inlet of the evaporator 24. The expansion valve 30 has a function of reducing the pressure of the high-pressure refrigerant liquid by squeezing and expanding it to form low-temperature low-pressure wet vapor in a gas-liquid mixed state. The wet steam guided to the evaporator 24 absorbs heat of vaporization from the air in the booth 4 to become a refrigerant gas, while cold air is supplied into the booth 4. The evaporator 24 and the intake side of the compressor 22 are connected to the unit connecting pipe 1
It is connected by the gas pipe 32 in the No. 2. Evaporator 24
The refrigerant gas generated in 1 rises in the gas pipe 32 by the suction operation of the compressor 22. A suction accumulator 34 is provided at the inlet of the compressor 22. This is the evaporator 2
This is a container that temporarily stores the refrigerant gas discharged from No. 4 and acts as a buffer in the case of a transient phenomenon of operation or an excessive amount of refrigerant filled.

Next, the natural circulation loop will be described. Most of them are common with the vapor compression refrigeration cycle described above. The natural circulation loop has one suction accumulator 3
4 is different from the vapor compression refrigeration cycle in that the compressor 4 and the compressor 22 are bypassed. The natural circulation loop has bypass pipes 36 and 38 for these bypasses, respectively. Switching of these flow paths is performed by switching valves 40, 42, 44 and 46. That is, when this refrigeration cycle is used as a vapor compression refrigeration cycle (referred to as forced circulation mode), the switching valves 40 and 44 are opened and the switching valves 42 and 46 are closed. Conversely, when the refrigeration cycle is used as a natural circulation loop (referred to as a natural circulation mode), the switching valve 42,
46 is opened and the switching valves 40 and 44 are closed.

In the natural circulation loop, there is no driving force for the refrigerant circulation by the compressor 22. In this case, the refrigerant liquid generated in the condenser 20 descends in the liquid pipe 28 due to gravity and is accumulated therein. That is, the gravity acting on the refrigerant liquid accumulated in the liquid pipe 28 becomes the driving force for the refrigerant circulation. The refrigerant liquid is supplied by gravity to the evaporator 24, where it becomes a refrigerant gas. This refrigerant gas is guided to the gas pipe 32 side having a low pressure. The evaporator 24 side of the gas pipe 32 is a generation source of the refrigerant gas, while the condenser 20 side is an absorption source of the refrigerant gas, so that a pressure gradient is generated in the gas pipe 32. That is, the gas pressure on the condenser 20 side is equal to that of the evaporator 24.
Since it is lower than the side, the refrigerant gas rises in the gas pipe 32 and reaches the condenser 20.

The above is the mechanism of the natural circulation loop. Therefore, in the natural circulation loop, the condenser 20 must be higher than the evaporator 24 to some extent in order to obtain the driving force by gravity and the required cooling capacity. When the difference between the temperature inside the booth 4 (more accurately in the vicinity of the evaporator 24) where the heat load is generated and the outside air temperature is 5 ° C. or more, a test device for confirming the operation of the cooling system naturally It is possible to release the heat load in the booth to the outside air by the circulation mode operation, and the indoor unit 8 and the outdoor unit 10 are connected by a conduit that is normally used as a refrigerant flow path, and the liquid pipe 28 is connected to the liquid pipe 28. It was confirmed that when the refrigerant liquid was filled up to the vicinity of the outlet of the condenser 20, the height difference ΔH should be about 2 m.

In this communication relay base station package, since the cooling system is the natural circulation combined cooling system as described above, when the cooling capacity is not required so much,
For example, in the winter season, the natural circulation mode can be used. In the natural circulation mode, since it is not necessary to operate the compressor 22 as described above, less electric power is consumed and operating power cost is saved. Further, when the outside air temperature is low, the compressor 22 can be stopped in the natural circulation mode, so that the useful life of the compressor 22 becomes long,
The mean time between failures (MTBF) of the cooling system is increased.
By increasing the reliability of the cooling system,
The possibility that expensive electronic equipment in the booth 4 is damaged or the communication system is down is reduced. Thus, the combined use of the natural circulation loop has great advantages.

In this communication relay base station package,
I adopted a cooling system with natural circulation, but not necessarily
It is not necessary to be a combination type. In other words, it is sufficient to use the combined use type only in a place where the cooling capacity of the natural circulation loop may be insufficient, and in a cold region or the like, only the natural circulation loop may be used.

By the way, as described above, recently, the communication relay base station package is assembled in a factory, transported by a truck or the like, and installed on site. This is because the cost can be reduced by assembling them together in the factory, and the installation work period can be shortened. When transporting and installing the pre-assembled product in this way, there is a limit to its size. For example, there are restrictions relating to truck transportation from the factory to the site, transportation to the roof of the building by elevator, crane, and the like. In particular, the strength of the communication relay base station package is generally designed assuming the installation state. Therefore, in order to avoid damage, it is desirable to stand and transport the same as in the installed state, so that the height is limited.

In this communication relay base station package, the outdoor unit 10 is arranged on the upper outside of the booth 4, and the indoor unit 8 is arranged on the floor surface inside the booth 4, and the height difference Δ
Since it was decided to secure H, the total height of the communication relay base station package could be suppressed to about 2 m, which is not a problem with the above various restrictions.

Now, in this communication relay base station package,
Since the indoor unit 8 is arranged at a low position, the air cooled thereby tends to stay in the lower part of the booth 4 and conversely warm air tends to stay in the upper part. The blower 14 forming a part of the present cooling system is for eliminating this. The blower 14 is a stirring fan that is rotated by a motor, and is installed on the ceiling of the booth 4. Blower 14 is booth 4
The warm air at the upper part of the booth is blown downward to equalize the temperature inside the booth 4. If the blower 14 is not provided, the temperature will be 15 at the bottom of the booth 4, for example, during the daytime in summer.
On the other hand, there is a large temperature difference between the upper and lower parts, i.e. At such temperature, efficient cooling cannot be performed not only in the natural circulation loop but also in the vapor compression refrigeration cycle. As described above, the blower 14 has an extremely important function in the cooling system of the communication relay base station package. Note that the compressor 22 performs the large work of compressing the refrigerant gas, but
The stirring action performed by 4 consumes much less energy.

The blower 14 does not necessarily have to be provided on the ceiling inside the booth 4, and may be arranged at a location where efficient stirring is performed depending on the arrangement of the electronic device 6 and the indoor unit 8 inside the booth 4. . Further, the structure can be other than the stirring fan. For example, a blower provided along with a duct that draws in air from the front surface of the indoor unit 8 and blows cooled air from the upper part of the unit, or a duct that extends from the indoor unit 8 to a height near the upper part of the booth. May be used to suck the warm air in the upper part of the booth 4 and blow it to the indoor unit 8.
In addition, anything can be used as long as the air can be stirred.

The cooling system can be applied to other than the communication relay base station. For example, it can be applied to facilities where height restrictions are imposed, various booths that can be moved by being mounted on a vehicle, and various temporary booths.

[0024]

According to the present invention, in a cooling system for a communication relay base station package to be transported and installed, a natural circulation loop is used to save energy and to uniformly cool the inside of the booth of the communication relay base station package. There is an effect that it is possible to obtain a cooling system that secures stable operation, suppresses the height of the communication relay base station package, and facilitates transportation and installation thereof.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a communication relay base station package according to an embodiment of the present invention as seen from a side surface.

FIG. 2 is a schematic diagram showing a configuration of a refrigeration cycle portion of a cooling system.

[Explanation of symbols]

2 heat insulating walls, 4 booths, 6 electronic devices, 8 indoor units, 10 outdoor units, 12 unit connecting pipes, 14 blowers, 20 condensers, 22 compressors, 24
Evaporator.

Claims (2)

[Claims] 1. A cooling system for cooling the inside of a portable closed booth housing a communication relay device, wherein the cooling system for a communication relay base station is attached to the closed booth and transported. An evaporator attached to the inner lower part, which absorbs the heat of vaporization when the refrigerant liquid becomes a refrigerant gas from the inside of the closed booth, and an outer upper part of the closed booth attached to the refrigerant gas generated in the evaporator. A natural circulation loop that includes a condenser that liquefies the refrigerant liquid and returns it to the evaporator; and a blower that makes the air temperature in the closed booth uniform, and that is driven using the height of the closed booth. A cooling system characterized by 2. The cooling system for a communication relay base station according to claim 1, wherein the blower is a stirring fan attached to an inner upper portion of the closed booth.