JPH0794926B2 - Refrigerating device for both low temperature medium and high temperature medium - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a refrigerating apparatus for cooling both low-temperature medium and high-temperature medium for effectively cooling in a low-temperature region to perform cooling in a solid-higher temperature region. Is.

[Conventional technology]

This type of low temperature medium and high temperature medium combined cooling refrigeration system can be used for 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 reproduce. And this environment maintenance room has a wide control range, for example -40 ℃
The temperature condition can be reproduced in a wide range from + 50 ° C to + 50 ° C, and when the humidity limit is as high as + 50 ° C, a high condition such as 90% can be reproduced.

Conventionally, a direct expansion refrigerator is known as a low-temperature medium and high-temperature medium combined cooling refrigeration apparatus used in such an apparatus.

This will be described with reference to FIG.

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

First, the high-pressure gas compressed by the compressor 1 is sent to the condenser 2 through the high-pressure gas line 7 and then compressed by the condenser 2
Condensate and liquefy. This is sent to the low pressure receiver 4 via the high pressure liquid line 8. The high-pressure liquid is expanded by the expansion valve 3 provided in front of the low-pressure receiver 4 into a cold liquid and at the same time 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 is used. Circulate.

As a result, the medium to be cooled passing through the evaporator 6 can be cooled.

[Problems to be Solved by the Invention]

However, such a conventional refrigeration system has the following problems.

In the conventional refrigeration cycle, the temperature of the heat medium to be cooled is
For example, when the temperature is + 50 ° C, the cooling-side heat medium temperature is 5 to 6 ° C lower than the cooled-side heat medium temperature, that is, 4
A temperature of around 5 ° C is appropriate. However, it is necessary to raise the condensing pressure abnormally or to provide a pump to pressurize and supply the evaporator. Therefore, in general, the temperature of the heat medium on the cooling side can be raised only up to about 20 ° C., which causes excessive dehumidification of the evaporator.

As a result, not only the running cost is increased, but also the sensible cooling is insufficient and the refrigerator may be large. In addition, there is an irrationality to perform the refrigeration cycle in an operating place where the temperature of the cooling water (high temperature exhaust heat side) is lower than the cooling temperature (low temperature heat absorption side).

Conventionally, natural refrigerant circulation has been known as a means for solving such a problem.

According to the natural circulation of the refrigerant, for example, even when the temperature is + 50 ° C., when the air needs to be cooled, even if the outside air reaches 32 ° C., it can be cooled without rotating the refrigerator.

Thus, the natural circulation of the refrigerant not only solves the irrationality of performing the refrigeration cycle in the driving place where the cooling water temperature is lower than the cooling temperature, but also operates independently of the refrigeration cycle and the cooling heat medium temperature. Is an intermediate temperature to the temperature of the heat medium to be cooled, and there is no great difference between the temperature of the heat medium to be cooled and the temperature of the heat medium to be cooled unlike in the case of the operation of the refrigeration cycle.
Therefore, even the evaporator can be operated without excessive dehumidification.

However, in the natural circulation of the refrigerant, the capacity is limited by the weather conditions.Therefore, if the set temperature fluctuates drastically like the above-mentioned environment control room, it will not be possible to operate in balance with the outside air, However, due to lack of ability or various conditions, it is not actually implemented.

The present invention has been made to solve such conventional problems, the object is to incorporate a refrigeration cycle that does not use a compressor similar to the refrigerant natural circulation in the refrigeration cycle by a normal direct expansion refrigerator, the refrigerant When a cooling operation that does not use a compressor similar to natural circulation is performed, and when the cooling function by this cooling operation is not sufficiently achieved, a low temperature field is formed using the compressor by switching operation and it continuously approximates the refrigerant natural environment. By devising so that the cooling operation without using the compressor can be achieved, the cooling in the low temperature region can be performed both in the low temperature medium and the high temperature medium so that the cooling in the high temperature region can be performed reasonably and economically. It is to provide a refrigerating device for cooling.

[Means for Solving the Problems]

The refrigerating apparatus for cooling a low temperature medium and a high temperature medium according to 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 condenser and the low pressure receiver are connected by the high pressure liquid line through the expansion valve, the low pressure receiver and the evaporator are connected by the low pressure liquid line through the liquid pump, and the evaporator and the low pressure receiver are connected. In a refrigeration system formed by connecting a first low-pressure gas line and a low-pressure receiver and a compressor to a second low-pressure gas line, a high-pressure gas line and a first low-pressure gas line Are connected by a first bus pass line having a first switching valve interposed therebetween, and a high pressure liquid line and a second low pressure gas line are provided with a second switching valve, a second expansion valve and an indirect cooler. Connected with the first bus pass line and low pressure A third bypass line having a third switching valve interposed is connected to the sheaver, and the third bypass line is passed through an indirect cooler provided in the second bypass line so as to be thermally connected to the second bypass line. The second low-pressure gas line is provided with a fourth switching valve on the low-pressure receiver side with respect to the connection part with the first bypass line in the first low-pressure gas line, and the evaporation pressure adjusting valve is provided on the second low-pressure gas line. A fifth switching valve is provided between the expansion valve in the line and the connecting portion of the second bypass line.

[Work]

In the present invention, when the temperature of the cooling water is sufficiently lower than the temperature of the medium to be cooled, the compressor is stopped, the first switching valve is opened, and the second switching valve, the third switching valve and the evaporation pressure adjusting valve are opened. By closing and opening the expansion valve, the refrigerant is circulated through the path of condenser → low pressure receiver → liquid pump → evaporator → first bypass line → condenser by natural circulation of the refrigerant.

In the operation without using a compressor similar to the above-described natural refrigerant circulation, when the cooling capacity is insufficient, the first switching valve is closed, the fifth switching valve is closed, the second switching valve is opened, and the compressor is closed. Drive the refrigerant to the compressor → condenser → second expansion valve →
Circulate the path from indirect cooler to compressor. In parallel with this, the fourth switching valve of the third bypass line is opened, and the refrigerant is circulated through the path of low pressure receiver → liquid pump → evaporator → indirect cooler → low pressure receiver. Thus, the refrigerant circulating in the path on the evaporator side is forcibly cooled by the cold refrigerant on the compressor side in the indirect cooler, and the medium to be cooled passing through the evaporator can be cooled by the natural refrigerant circulation. Therefore, for example, even when cooling a high temperature heat medium of 50 ° C,
Not only can the evaporator side be cooled in the optimum temperature field, but also the compressor side can be operated at a cooling heat medium temperature of 20 ° C or lower.

When the first switching valve, the second switching valve and the third switching valve are closed and the fourth switching valve is opened and the compressor is driven, the refrigerant is compressed → condenser → expansion valve → low pressure receiver → liquid pump → evaporation. It circulates in the route of the container → low pressure receiver → compressor.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 show a refrigerating apparatus for cooling both a low temperature medium and a high temperature medium according to an embodiment of the present invention, and 20 denotes a compressor.

The compressor 20 is connected to a condenser 22 via a high pressure gas line 21. The condenser 22 is connected to a low pressure receiver 25 via a high pressure liquid line 23. This high pressure liquid line 23
A fifth switching valve 41 and an expansion valve 24 are interposed in the. The liquid side of the low pressure receiver 25 is connected to an evaporator 28 via a low pressure liquid line 27. A liquid pump 26 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 25 are connected via a first low pressure gas line 29. A fourth switching valve 39 is provided in the first low pressure gas line 29. The low pressure receiver 25 is also connected to the compressor 20 via a second low pressure gas line 30. An evaporation pressure adjusting valve 40 is provided in the second low pressure gas line 30.

Thus, the compressor 20 → condenser 22 → expansion valve 24 → low pressure receiver 25 → liquid pump 26 → evaporator 28 → low pressure receiver 25 → compressor
A circulation circuit of 20 will be formed.

Further, the first low pressure gas line 29 and the high pressure gas line 21 are connected by a first bypass line 31. A first switching valve 32 is attached to the first bypass line 31.

Further, the high pressure liquid line 23 and the second low pressure gas line 30 are connected by a second bypass line 33. A second switching valve 34, a second expansion valve 35, and an indirect cooler 36 are provided in the second bypass line 33. The connecting portion between the second bypass line 33 and the high pressure liquid line 23 is located closer to the condenser 22 than the expansion valve 24 in the high pressure liquid line 23.

Furthermore, the first bypass line 31 and the low-voltage receiver 25,
They are connected by a third bypass line 37. The third bypass line 37 penetrates through the indirect cooler 36 provided in the second bypass line 33 and is cooled by the indirect cooler 36. In addition, the third bypass line 37 is connected to the first bypass line 31 rather than the indirect cooler 36.
A third switching valve 38 is provided on the side.

Next, the operation of this embodiment configured as described above will be described.

First, when the temperature of the cooling water for cooling the condenser 22 is higher than the temperature of the cooling medium passing through the evaporator 28, for example, the temperature of the cooling water is 32 ° C and the temperature of the cooling medium (air) is 10 ° C. In this case, normal operation as shown in FIG. 2 can be performed.

In order to perform this normal operation, the first switching valve 32 of the first bypass line 31 and the second switching valve 34 of the second bypass line 33.
And the third switching valve 38 of the third bypass line 37 are closed to form a circulation path indicated by a thick line.

In this normal operation, the high-pressure gas compressed by the compressor 20 and sent by the compressor 20 is sent to the condenser 22 through the high-pressure gas line 21, and is condensed and liquefied by the condenser 22. This is a high pressure liquid line
To a low voltage receiver 25 via 23. This low voltage receiver 25
The high-pressure liquid is expanded to a cold liquid by the expansion valve 24 provided in front of and at the same time partially vaporized. The cold liquid sent to the low-pressure receiver 25 is sent to the evaporator 28 by the liquid pump 26 via the low-pressure liquid line 27. In the evaporator 28, heat is exchanged with the medium to be cooled (air) to be gasified, and the gas returns from the evaporator 28 to the low pressure receiver 25 through the first low pressure gas line 29, and a part of the cold gas is generated. It is sent to the compressor 20 via the second low pressure gas line 30 and circulates in the circuit as described above.

And, for example, the cooling water temperature is 20 ° C.
In case of ℃, the temperature of cooling water is 5 ℃ and the temperature of the object to be cooled is 20 ℃
When the temperature of the cooling water is sufficiently lower than the temperature of the medium to be cooled, as in the case of (3), the operation can be performed without using a compressor similar to the natural circulation of the refrigerant as shown in FIG.

In order to bring this operation state, the compressor 20 is stopped, the fourth switching valve 28 of the first low pressure gas line 29, the evaporation pressure adjusting valve 40 of the second low pressure gas line 30, and the second bypass line 33. By closing the third switching valve 34 and the switching valve 38 of the third bypass line 37, the circulation path shown by the thick line can be formed.

This circulation path is a cooling operation similar to a so-called natural refrigerant circulation that does not use a compressor, and the refrigerant condensed and liquefied in the condenser 22 is sent to the low-pressure receiver 25 via the high-pressure liquid line 23. At this time, the expansion valve 24 provided in the high pressure liquid line 23,
It does not function as an expansion valve and does not hinder the flow of high-pressure liquid that passes through it. Then, the cold liquid sent to the low-pressure receiver 25 is sent to the evaporator 28 by the liquid pump 26 via the low-pressure liquid line 27. This evaporator
At 28, heat exchange with the medium to be cooled (air) and gasification,
The gas flows from the evaporator 28 into the first bypass line 31 from the middle of the first low pressure gas line 29 and is sent to the condenser 22. Then, the circuit as described above is circulated again.

And, for example, the temperature of the cooling water is 30 ° C.
When the difference between the two becomes small or disappears at a temperature of ° C, a low temperature field is formed using the compressor 20 to increase the cooling function, as shown in Fig. 4.

To achieve this operating state, the first switching valve 32 of the first bypass line 31, the fifth switching valve 41 of the high-pressure liquid line 23, the fourth switching valve 28 of the first low-pressure gas line 29, and the second The evaporation pressure adjusting valve 40 of the low-pressure gas line 30 is closed, the second switching valve 34 of the second bypass line 33 and the third switching valve 38 of the third bypass line 37 are opened, and the compressor 20 is driven. As a result, two cooling circulation paths A and B indicated by thick lines can be formed.

The cooling circulation path A is a cooling path that does not use a compressor and is similar to a so-called refrigerant natural environment.
Corresponds to the direct expansion cooling circuit.

First, in the cooling circulation path B, the compressor 20 compresses the
The high-pressure gas compressed in 20 is sent to the condenser 22 via the high-pressure gas line 21, and is condensed and liquefied in the condenser 22. This is sent to the indirect cooler 36 via the high pressure liquid line 23. The second expansion valve 35 provided in front of the indirect cooler 36 expands the high-pressure liquid into a cold liquid. After that, the route of returning to the compressor 20 is circulated.

On the other hand, in the cooling circulation path A, the gasified refrigerant is condensed and liquefied by passing through the indirect cooler 36, and is sent to the low-pressure receiver 25 via the third bypass line 37. Then, the cold liquid sent to the low-pressure receiver 25 is sent to the evaporator 28 by the liquid pump 26 via the low-pressure liquid line 27. In the evaporator 28, heat is exchanged with the medium to be cooled (air) to be gasified, and the gas flows into the first bypass line 31 from the middle of the first low pressure gas line 29 from the evaporator 28 and is again indirect. It passes through the cooler 36 and again circulates in the circuit as described above.

As described above, according to this embodiment, when the temperature of the cooling water is higher than the temperature of the medium to be cooled by switching the switching valve,
Performing a normal refrigeration cycle operation, when the cooling water temperature is sufficiently lower than the temperature of the medium to be cooled, perform a cooling operation without using a compressor similar to natural refrigerant circulation,
In addition, when there is no difference between the temperature of the cooling water and the temperature of the medium to be cooled, the compressor is driven to forcibly form the low temperature field, thereby cooling without using a compressor similar to natural refrigerant circulation. You can continue driving. Therefore, in particular, in an environment control room that requires cooling at a high temperature of 40 ° C. to 50 ° C., for example, it is possible to continuously operate cooling in a high temperature range without using a compressor similar to natural refrigerant circulation. Becomes possible,
The cooling heat medium temperature of the evaporator is not lowered to around 20 ° C unlike the conventional refrigeration cycle operation, and is effectively cooled at a temperature 5 to 7 ° C lower than the cooled heat medium temperature without excessive dehumidification. In addition, the compressor side can be operated without difficulty in a low pressure field of 20 ° C. or less. Moreover, when the cooling water becomes sufficiently low and it is not necessary to operate the compressor, the compressor can be stopped immediately.

〔The invention's effect〕

As described above, the present invention includes a compressor, a condenser, an expansion valve, a low pressure receiver, a liquid pump, and an evaporator, connects the compressor and the condenser with a high pressure gas line, and connects the condenser and the low pressure receiver to each other. Is connected with a high pressure liquid line via an expansion valve, the low pressure receiver and the evaporator are connected with a low pressure liquid line via a liquid pump, and the evaporator and the low pressure receiver are connected with a first low pressure gas line. In a refrigeration system in which a low pressure receiver and a compressor are connected to a second low pressure gas line to form a refrigeration cycle, the high pressure gas line and the first low pressure gas line are connected via a first switching valve. The first high-pressure liquid line and the second low-pressure gas line are connected by the second bus-pass line including the second switching valve, the second expansion valve, and the indirect cooler. The line and the low-pressure receiver are provided with a third switching valve. The third bypass line is connected, and the third bypass line is penetrated through the indirect cooler provided in the second bypass line to be thermally connected to the second bypass line to the first low pressure gas line. A fourth switching valve is provided on the low pressure receiver side with respect to the connection part with the first bypass line in the first bypass line, an evaporation pressure adjusting valve is provided in the second low pressure gas line, and an expansion valve and a second bypass in the high pressure liquid line are provided. Since the fifth switching valve is provided between the line and the connecting portion, for example, the cooling water temperature is about 5 to 32 ° C. annually, and the temperature of the cooled medium is often sufficiently higher than the cooling water temperature. In the environmental control room, it is possible to stop the compressor and cool it by cooling that does not use a compressor similar to natural refrigerant circulation, and the running cost is much higher than that of the conventional refrigerator cooling system. Cheap and Become. Further, since it becomes possible to eliminate the irrationality of operating the compressor in the case where the temperature of the heat-cooling medium is higher than the temperature of the cooling water, the superiority of the system is high. Further, since three kinds of modes can be selected by switching the switching valve, it is possible to smoothly shift to any operation mode.

[Explanation of symbols of main parts]

 20 …… Compressor 21 …… High pressure gas line 22 …… Condenser 23 …… High pressure liquid line 24 …… Expansion valve 25 …… Low pressure receiver 26 …… Liquid pump 27 …… Low pressure liquid line 28 …… Evaporator 29… … First low pressure gas line 30 …… Second low pressure gas line 31 …… First bypass line 32 …… First switching valve 33 …… Second bypass line 34 …… Second switching valve 35 …… Second expansion valve 36 Indirect cooler 37 Third bypass line 38 Third switching valve 39 Fourth switching valve 40 Evaporation pressure control valve 41 Fifth switching valve.

Claims (1)

[Claims] 1. A compressor, a condenser, an expansion valve, a low pressure receiver, a liquid pump, and an evaporator are provided, 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. And a low pressure receiver and an evaporator are connected by a low pressure liquid line through a liquid pump, and an evaporator and a low pressure receiver are connected by a first low pressure gas line. In a refrigeration system in which a refrigeration cycle is formed by connecting a compressor and a second low-pressure gas line, a high-pressure gas line and a first low-pressure gas line are provided with a first switching valve. Connected by a bus pass line, the high pressure liquid line and the second low pressure gas line are connected by a second bus pass line with a second switching valve, a second expansion valve and an indirect cooler interposed,
The first bus pass line and the low-pressure receiver are connected to a third bypass line having a third switching valve interposed therebetween, and the third bypass line is passed through an indirect cooler provided in the second bypass line, The second bypass line is thermally connected, and a fourth switching valve is provided on the low pressure receiver side with respect to the connection part with the first bypass line in the first low pressure gas line,
A low-temperature medium characterized in that an evaporation pressure adjusting valve is provided in the second low-pressure gas line, and a fifth switching valve is provided between the expansion valve in the high-pressure liquid line and the connecting portion of the second bypass line. And a refrigerating device for high temperature medium and cooling.