JP2756362B2 - Refrigeration system for cooling both low temperature medium and high temperature medium - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration system for cooling both a low-temperature medium and a high-temperature medium for effectively cooling not only in a low-temperature region but also in a high-temperature region. is there.

[Conventional technology]

This type of low-temperature and high-temperature medium cooling refrigeration system reproduces various weather conditions on the earth, such as an environment maintenance room that reproduces weather conditions, an automobile-related test room, and a plant laboratory. Used to do. And this environment maintenance room has a wide control range, and reproduces temperature conditions in a wide range, for example, -40 ° C to + 50 ° C.
When the humidity limit becomes high, such as + 50 ° C, the condition as high as 90% may be reproduced.

Conventionally, as a refrigerating device for cooling both low-temperature medium and high-temperature medium used in such a device, a device using a direct expansion refrigerator is known.

 This will be described with reference to FIG.

A refrigerating apparatus using the direct expansion refrigerator includes a compressor (refrigerator) 1, a condenser 2, an expansion valve 3, a low-pressure receiver 4, a liquid pump 5, and an evaporator 6, and includes a compressor 1, a condenser 2 Are connected by a high-pressure gas line 7, the condenser 2 and the low-pressure receiver 4 are connected via an expansion valve 3, and are connected via a high-pressure liquid line 8, and the low-pressure receiver 4 and the evaporator 6 are connected via a liquid pump 5. By connecting the low pressure liquid line 9, connecting the evaporator 6 and the low pressure receiver 4 with the first low pressure gas line 10, and connecting the low pressure receiver 4 and the compressor 1 with the second low pressure gas line 11. A refrigeration cycle is formed.

First, a refrigerant in a gaseous state is compressed into a high-pressure gas by the compressor 1, and the compressed high-pressure gas is sent to the condenser 2 via the high-pressure gas line 7, and is condensed and liquefied by the condenser 2. This is sent to the low-pressure receiver 4 via the high-pressure gas line 8. The high pressure liquid is expanded by the expansion valve 3 provided in front of the low pressure receiver 4 to become a cold liquid and at the same time, is partially vaporized. The cold liquid sent to the low-pressure receiver 4 is sent to the evaporator 6 by the liquid pump 5 via the low-pressure liquid line 9. The gas leaving the evaporator 6 returns to the low-pressure receiver 4 via the first low-pressure gas line 10, and a part of the cold gas is sent to the compressor 1 via the second low-pressure gas line 11, and the circuit as described above To form

Thereby, the cooling medium air to be cooled passing through the evaporator 6 can be cooled.

[Problems to be solved by the invention]

In conventional refrigeration equipment, even when the temperature and humidity of the cooling medium air is higher than the temperature and humidity of the natural world such as outside air and well water,
The refrigeration cycle was operated for cooling.

However, when the temperature and humidity of the cooling medium air to be cooled are high temperature and high humidity, the refrigerant temperature cannot be raised to a high temperature in a normal refrigeration cycle operation. Moisture occurs, the amount of sensible heat cooling is insufficient, and not only does the refrigerating device become unnecessarily large, but also the running cost increases because the compressor 1 is operated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object thereof is to condense and liquefy a refrigerant using inexpensive cold heat such as outside air or well water when the air to be cooled is high temperature and high humidity. Accordingly, an object of the present invention is to provide a low-temperature medium and high-temperature medium cooling refrigerating apparatus that can cool the heat medium to be cooled without causing excessive local humidity.

[Means for solving the problem]

In order to achieve the above object, the present invention includes a compressor, a condenser, an expansion valve, a low-pressure receiver, a liquid pump, and an evaporator, and connects the compressor and the condenser with a high-pressure gas line. The low pressure receiver is connected with a high pressure liquid line with an expansion valve interposed, the low pressure receiver and the evaporator are connected with a low pressure liquid line with a liquid pump interposed, and the evaporator and the low pressure receiver are connected with the first low pressure gas. In a refrigeration system in which a refrigeration cycle is formed by connecting a low-pressure receiver and a compressor to a second low-pressure gas line by using a line, a first switching valve and natural cold energy are used above the low-pressure receiver. And a cooling circuit for cooling the cooling medium, and a cooling circuit in which a second switching valve is sequentially interposed.

(Operation)

In the present invention, when the temperature of the cooling medium air to be cooled in the evaporator is lower than the natural cooling temperature in the refrigerant cooler, the first switching valve and the second switching valve are closed, and the compressor is driven to operate the refrigerant. Circulate through the path of compressor → condenser → expansion valve → low pressure receiver → liquid pump → evaporator → low pressure receiver → compressor.

Thus, a refrigeration cycle is formed, and the cooling medium air to be cooled is cooled by the evaporator.

On the other hand, when the temperature of the cooling medium air in the evaporator is higher than the natural cooling temperature in the refrigerant cooler, the compressor is stopped, the first switching valve and the second switching valve are opened, and the refrigerant is evaporated from the evaporator to the first. Circulate in the path of low pressure gas line → low pressure receiver → refrigerant cooler → low pressure receiver → liquid pump → evaporator.

As a result, the refrigerant exchanges heat with the cooling medium air to be cooled in the evaporator and evaporates (vaporizes), and the refrigerant that has become vapor exchanges heat with natural cold heat such as outside air or well water in the refrigerant cooler to perform cooling / cooling. Condensed.

In this case, if the refrigerant gas and the refrigerant oil are contained in the refrigerant gas guided from the evaporator to the low pressure receiver, the refrigerant gas is separated from the refrigerant liquid and the refrigerant oil in the low pressure receiver, and only the refrigerant gas passes through the cooling circuit. Through the refrigerant cooler.

When switching between a refrigeration system using a compressor and a cooling system using a refrigerant cooler, for example, in the case of switching from the former to the latter, a low-pressure receiver is located between the first low-pressure gas line and the cooling circuit. Therefore, the low-pressure receiver performs the function of gas-liquid separation, and only the refrigerant gas is carried to the refrigerant cooler, where the refrigerant gas undergoes a phase change and is condensed into the refrigerant liquid.

〔Example〕

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

1 to 3 show a cooling refrigerating apparatus for both low-temperature medium and high-temperature medium according to an embodiment of the present invention.

In FIG. 1, reference numeral 20 denotes a compressor, which is connected to a condenser 22 through a high-pressure gas line 21. The condenser 22 is connected to the liquid side of the low-pressure receiver 24 via a high-pressure liquid line 23. In this high-pressure liquid line 23, a third switching valve 25 and an expansion valve 26 are interposed. The liquid side of the low-pressure receiver 24 is connected to an evaporator 28 via a low-pressure liquid line 27. A liquid pump 29 is interposed in the low-pressure liquid line 27.

The outlet side of the evaporator 28 and the gas side of the low-pressure receiver 24 are connected via a first low-pressure gas line 30.

Both ends of a cooling circuit 32 are connected to the upper side 31 of the low-pressure receiver 24. In this cooling circuit 32, a first switching valve 33, a refrigerant cooler 34, and a second switching valve 35 are interposed in order from the low-pressure receiver 24 side. The refrigerant cooler 34 cools the refrigerant from the outside air using natural cold heat such as well water.

The low-pressure receiver 24 and the compressor 20 are connected via a second low-pressure gas line 36.

In the present embodiment, the temperature of the cooling medium air to be cooled is −20 ° C.
The operation of the present embodiment will be described as follows. The operation is performed in the range of + 50 ° C. and the humidity in the range of 30% to 90%.

First, when the temperature of the cooling medium air in the evaporator 28 is lower than the natural cooling temperature in the refrigerant cooler 34, the normal operation as shown in FIG. 2 can be performed.

In order to perform this normal operation, the first switching valve 33 and the second switching valve 35 are closed and the third switching valve 25 is opened to form a circulation path indicated by a thick line.

In this normal operation, the high-pressure gas compressed by the compressor 20 is sent to the condenser 22 via the high-pressure gas line 21, and is condensed and liquefied by the condenser 22. This is sent to the low pressure receiver 24 via the high pressure liquid line 23. The high-pressure liquid is expanded by the expansion valve 26 provided in front of the low-pressure receiver 24 to become a cold liquid and at the same time, is partially vaporized. The cold liquid sent to the low-pressure receiver 24 is sent to the evaporator 28 by the liquid pump 29 via the low-pressure liquid line 27. In the evaporator 28, the gas is exchanged with the heat medium air to be cooled and gasified, and the gas is returned from the evaporator 28 to the low-pressure receiver 24 via the first low-pressure gas line 30. Through the compressor
20 and circulates through the circuit as described above.

Thus, a refrigeration cycle is formed, and the cooling medium air to be cooled is cooled by the evaporator 28.

On the other hand, when the temperature of the cooling medium air is higher than the natural cooling temperature, the operation can be performed as shown in FIG.

To achieve this operation, the compressor 20 is stopped, and the first switching valve 33 and the second switching valve 35 are opened to form a circulation path indicated by a thick line.

This circulation path is a cooling cycle using the refrigerant cooler 34 without using the compressor 20, and the refrigerant is the evaporator 28 → the first low pressure gas line 30 → the low pressure receiver 24 → the refrigerant cooler 34 → the low pressure receiver 24 It circulates in the path of → liquid pump 29 → evaporator 28.

As a result, the refrigerant is heat-exchanged with the air to be cooled in the evaporator 28 to evaporate (evaporate), and the vaporized refrigerant is heat-exchanged with natural air such as outside air or well water in the refrigerant cooler 34, Cooled and condensed. For example, as natural cold
When using outside air at 32 ° C, set the temperature of the cooling medium air to 45 ° C.
When well water of 15 ° C. is used as natural cooling heat, the temperature of the cooling medium air can be set to about 30 ° C.

Here, for the purpose of improving the heat transfer characteristics and efficiency of the evaporator 28, an excess refrigerant liquid is supplied to the evaporator 28 by the liquid pump 29, so that a part of the refrigerant liquid is supplied to the first low-pressure gas line 30. The refrigerating machine oil that has flowed in and dissolved in the refrigerant liquid may be separated by evaporation of the refrigerant into oil droplets. In this case, the refrigerant gas, the refrigerant liquid, and the refrigerating machine oil are separated in the low-pressure receiver 24, and only the refrigerant gas is guided to the refrigerant cooler 34 via the cooling circuit 32.

When continuously raising or lowering the temperature and humidity of the cooling medium air, it is necessary to appropriately switch between the refrigeration system using the compressor 20 and the cooling system using the refrigerant cooler.

For example, in the case of switching from the former to the latter (the state shown in FIG. 2 → the state shown in FIG. 3), well water or the like is allowed to flow in the refrigerant cooler 34 in advance, and the temperature of the refrigerant cooler 34 is lowered to enable use. After the standby, the first switching valve 33 and the second switching valve 35 are switched from closed to open to put the refrigerant cooler 34 into an operating state, and then the compressor 20 of the refrigeration system is stopped. Therefore, switching between the refrigeration system and the cooling system is performed smoothly, and temperature fluctuations in the evaporator 28 are minimized.

Further, a cooling system using the refrigerant cooler 34 (shown in FIG. 3) is replaced by a refrigeration system using the compressor 20 (shown in FIG. 2).
To switch to the first switching valve 3
3. If the second switching valve 35 is switched from open to closed, the state of FIG. 3 is changed to the state of FIG.

According to the configuration as described above, when the temperature of the cooling medium air is higher than the natural cooling temperature, the temperature of the cooling medium air can be lowered by using the natural cooling without using the refrigeration cycle. it can.

In this case, even when the cooling medium air is high temperature and high humidity, the cooling medium air can be cooled while maintaining the humidity (without excessive dehumidification).

Also, when the temperature and humidity of the cooling medium air is high temperature and high humidity,
Since the normal refrigeration cycle is not used as described above, the amount of sensible heat cooling due to excessive dehumidification as described in the conventional example does not decrease in the evaporator 28, and therefore, the compressor 20 of the refrigeration cycle Ability can be reduced,
The running cost due to the stoppage of the compressor 20 can also be reduced.

Here, if the operation range using the natural cooling heat is widened, the above-described effects can be remarkable. The range of the operation using the natural cold heat depends on the temperature field of the natural cold heat, the heat transfer area of the refrigerant cooler 34, the capacity of the liquid pump 29, and the like.

When the refrigeration cycle is not used, the vaporized refrigerant exchanges heat with natural cold heat such as outside air or well water in the refrigerant cooler 34, and is cooled and condensed.
Even if the refrigerant gas introduced from the evaporator 28 to the first low-pressure gas line 30 contains the refrigerant liquid and the refrigerating machine oil as described above,
In the low-pressure receiver 24, the refrigerant gas, the refrigerant liquid, and the refrigerating machine oil can be separated, and only the refrigerant gas can be guided to the refrigerant cooler 34 via the cooling circuit 32. Accordingly, it is possible to prevent the cooling efficiency of the refrigerant cooler 34 from decreasing. Thereby, the capacity of the refrigerant cooler 34 can be reduced, and the consumption of well water and the like can be reduced.

And, when switching between the refrigeration system using the compressor 20 and the cooling system using the refrigerant cooler 34, for example, in the case of switching from the former to the latter, between the first low-pressure gas line 30 and the cooling circuit 32 Since the low-pressure receiver 24 is located in the refrigerant cooler 34, only the refrigerant gas is carried to the refrigerant cooler 34, where the refrigerant gas changes phase and is condensed into the refrigerant liquid, and the cooling efficiency of the refrigerant cooler 34 is reduced. No lowering, cooling circuit 32
Temperature fluctuation at the time of switching can be minimized.

In this embodiment, an example in which the temperature of the cooling medium air to be cooled is in the range of −20 ° C. to + 50 ° C. and the humidity is in the range of 30% to 90% has been described, but the present invention is not limited to such a range. Of course.

〔The invention's effect〕

As described above, according to the low-temperature medium and high-temperature medium cooling refrigeration apparatus of the present invention, when the temperature of the cooling medium air to be cooled is higher than the natural cooling temperature, the refrigeration cycle is not used and natural cooling is used. By doing so, the temperature of the cooling medium air to be cooled can be lowered.

In this case, even when the cooling medium air is high temperature and high humidity, the cooling medium air can be cooled while maintaining the humidity (without excessive dehumidification).

Also, when the temperature and humidity of the cooling medium air is high temperature and high humidity,
Since the normal refrigeration cycle is not used as described above, the amount of sensible heat cooling due to excessive dehumidification does not decrease in the evaporator as described in the conventional example, and therefore, the capacity of the compressor of the refrigeration cycle Can be reduced, and the running cost due to the stoppage of the compressor can be reduced.

When the refrigeration cycle is not used, the vaporized refrigerant exchanges heat with natural cold heat such as outside air or well water in a refrigerant cooler, and is cooled and condensed. Even if the refrigerant gas guided to the low-pressure receiver via the
In the low-pressure receiver, the refrigerant gas can be separated from the refrigerant liquid and the refrigerating machine oil, and only the refrigerant gas can be led to the refrigerant cooler via the cooling circuit. Therefore, it is possible to prevent a decrease in cooling efficiency in the refrigerant cooler.

And, when switching between a refrigeration system using a compressor and a cooling system using a refrigerant cooler, for example, in the case of switching from the former to the latter, a low-pressure receiver is provided between the first low-pressure gas line and the cooling circuit. As it is located, the low-pressure receiver performs the function of gas-liquid separation, only the refrigerant gas is carried to the refrigerant cooler, and in the refrigerant cooler, the refrigerant gas undergoes a phase change and is condensed into the refrigerant liquid, and in the refrigerant cooler, There is an effect that the cooling efficiency is not reduced and the temperature fluctuation at the time of switching in the cooling circuit can be minimized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a low-temperature medium and high-temperature medium combined cooling refrigeration apparatus according to an embodiment of the present invention. FIG. 2 is an explanatory diagram showing a refrigeration cycle in the case where the temperature of the cooling medium air to be cooled is lower than natural cooling heat in the cooling refrigeration system for both low temperature medium and high temperature medium. FIG. 3 is an explanatory diagram showing a cooling cycle when the temperature of the cooling medium air to be cooled is higher than natural cooling heat in the cooling refrigeration system for both low-temperature medium and high-temperature medium. FIG. 4 is a configuration diagram showing a refrigeration apparatus using a conventional direct expansion refrigerator. [Description of Signs of Main Parts] 20… Compressor 21… High-pressure gas line 22… Condenser 23… High-pressure liquid line 24… Low-pressure receiver 26… Expansion valve 27… Low-pressure liquid line 28… Evaporator 29 ... Liquid pump 30 ... First low pressure gas line 32 ... Cooling circuit 33 ... First switching valve 34 ... Refrigerant cooler 35 ... Second switching valve 36 ... Second low pressure gas line.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Isao Nishio 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Co., Ltd. (56) References JP-A-2-302560 (JP, A) JP-A-2-223773 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) F25B 1/00

Claims (1)

(57) [Claims] A compressor, a condenser, an expansion valve, a low-pressure receiver, a liquid pump, and an evaporator, wherein the compressor and the condenser are connected by a high-pressure gas line, and the condenser and the low-pressure receiver are connected by an expansion valve. A low-pressure receiver is connected to the low-pressure receiver by connecting the low-pressure receiver and the evaporator with a low-pressure liquid line, and a low-pressure receiver is connected to the evaporator and the low-pressure receiver with the first low-pressure gas line. And a compressor connected to a second low-pressure gas line to form a refrigeration cycle, a first switching valve above the low-pressure receiver, a refrigerant that cools the refrigerant by utilizing natural cold heat A refrigerating apparatus for cooling both low-temperature medium and high-temperature medium, wherein both ends of a cooling circuit in which a cooler and a second switching valve are sequentially interposed are connected.