KR102294500B1 - Multistage compression type frozen apparatus - Google Patents

Abstract

The invention for a multi-stage compression type refrigeration system is disclosed. The multi-stage compression refrigeration apparatus of the present invention includes a compression unit in which the refrigerant is compressed at a plurality of compression stages, a condensing unit connected to the compression unit and the refrigerant passing through the compression unit is condensed by heat exchange, and the condensing unit, A reservoir in which the liquid refrigerant condensed in the condensing unit is stored, a first expansion valve unit installed in a pipeline connected to the reservoir to expand the refrigerant discharged from the reservoir, and the refrigerant passing through the first expansion valve unit A gas-liquid separator that separates the liquid refrigerant from the gaseous refrigerant and supplies the gas-liquid refrigerant to the compression unit; It is connected to the separation unit and the compression unit and includes an evaporator for converting the liquid refrigerant discharged from the gas-liquid separation unit into a gaseous refrigerant through heat exchange, and a gas-liquid separation unit may be installed in succession to the reservoir.

Description

Multi-stage compression refrigeration system {MULTISTAGE COMPRESSION TYPE FROZEN APPARATUS}

The present invention relates to a multi-stage compression refrigeration system.

A chiller can be used as a general refrigeration device. A chiller is a large cooling system that supplies cooling to a large building, and uses cold water or antifreeze as a refrigerant as a heat source transfer material.

A chiller is a device that supplies cold water to a consumer. In addition, the chiller cools the cold water by inducing heat exchange between the refrigerant circulating in the refrigerant cycle and the cold water circulating in the consumer. A refrigeration system using a chiller is a relatively large-capacity facility, and may be installed in a large-scale building or the like.

The chilled water cooled in a refrigeration system using a chiller is supplied to a consumer using an air conditioner or the like.

The chiller unit includes a compressor for compressing a refrigerant, a condenser for condensing the refrigerant compressed in the compressor, an expansion device for decompressing the refrigerant condensed in the condenser, and an evaporator for evaporating the refrigerant decompressed by the expansion device. The refrigerant used in a conventional refrigeration apparatus may exchange heat with external air in a condenser, and may exchange heat with cold water in an evaporator.

The chiller unit may be provided in various sizes or capacities. The size or capacity of the chiller unit is a concept corresponding to the refrigeration capacity and may be expressed in units of refrigeration ton (RT). The chiller unit may be manufactured as a facility having various refrigeration tones according to the size of a building in which the chiller unit is installed, the capacity of circulated cold water or air conditioning capacity, and the like. For example, the chiller unit may be manufactured as a model having a capacity of 200RT, 500RT, 1000RT, 1500RT, 2000RT, 3000RT, or the like.

When the compressor of the conventional refrigeration system compresses the refrigerant in multiple stages, a gas-liquid separator that is an economizer that separates the refrigerant in the gas phase and the refrigerant in the liquid phase may be installed.

In addition, the load control of the conventional refrigeration system is a method of mechanically controlling an inlet guide vane (IGV) of the compressor and a method of controlling the cooling capacity by a hot gas bypass (Hot Gas Bypass) are used. In the case of controlling the refrigeration system using only the inlet guide vane, the decrease in refrigeration efficiency is minimal compared to other methods, but the decrease in cooling capacity is not large, so it is difficult to cope with low-load operation with a small value of cooling capacity.

When the load control of the refrigerating device is not controlled only with the inlet guide vane, the refrigerant of the condenser is passed directly to the evaporator through the hot gas bypass, and in this case, there is a problem in that the refrigeration efficiency is greatly reduced.

Republic of Korea Patent Publication No. 2019-0006339 (published on January 18, 2019, title of invention: chiller unit and chiller system including the same)

SUMMARY OF THE INVENTION It is an object of the present invention to provide a multi-stage compression type refrigeration system capable of facilitating control of the cooling capacity of a refrigeration system and minimizing a decrease in refrigeration efficiency.

Another object of the present invention is to provide a multi-stage compression type refrigeration system that can easily control the cooling capacity even during the lowest load operation of the refrigeration system without using an inlet guide van or a hot gas bypass.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention not mentioned may be understood by the following description, and will be more clearly understood by the examples of the present invention. Moreover, it will be readily apparent that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

The control unit according to the present invention may control the control valve unit installed in the conduit for supplying the gas refrigerant to the compression unit having a plurality of compression stages to adjust the number of operations of the compression stages.

In addition, the gas-liquid separation unit according to the present invention may be sequentially blocked from the separation unit having a low pressure toward the separation unit having a high pressure.

A multi-stage compression type refrigeration system according to the present invention includes a compression unit in which refrigerant is compressed at a plurality of compression stages, a condensing unit connected to the compression unit and condensed by heat exchange of refrigerant passing through the compression unit, and discharged from the condensing unit It is installed in a conduit for guiding the movement of the refrigerant and has a first expansion valve unit for expanding the refrigerant, and a plurality of separation units. The refrigerant of the It is installed in a plurality of pipelines to include a control valve for controlling the movement of the refrigerant.

In addition, it may further include a control unit for controlling the operation of the control valve unit.

In addition, the gas-liquid separation unit is provided with a plurality of separation units for separating the transferred refrigerant into liquid refrigerant and gaseous refrigerant, and the number of separation units provided in the gas-liquid separation unit may be smaller than the number of compression stages provided in the compression unit. have.

In addition, the control unit may control the cooling capacity by sequentially blocking the conduit connected to the separation unit from the separation unit having the lowest pressure toward the separation unit having the highest pressure.

In addition, the compression unit includes a first compression unit that compresses the refrigerant delivered through the evaporator at a plurality of compression stages, and a first compression unit connected to the first compression unit and passing through the first compression unit and compressing the compressed refrigerant at the plurality of compression stages 2 It may include a compression unit.

In addition, the first compression unit may include a first compression stage for compressing the refrigerant transferred through the evaporator and a second compression stage installed in succession to the first compression stage and for re-compressing the refrigerant compressed at the first compression stage.

In addition, the second compression unit includes a third compression stage for compressing the refrigerant transferred through the second compression stage, and a fourth compression stage and a fourth stage installed in succession to the third compression stage and for re-compressing the refrigerant compressed at the third compression stage It is installed successively to the compression stage and may include a fifth compression stage for re-compressing the refrigerant compressed in the fourth compression stage.

In addition, the gas-liquid separation unit includes: a first separation unit connected to the first expansion valve unit; and a third separation unit and a third separation unit that are installed successively in the second separation unit and separate the refrigerant transferred from the second separation unit into a gaseous refrigerant and a liquid refrigerant, and are installed consecutively in the third separation unit may include a fourth separator for separating the refrigerant into a gaseous refrigerant and a liquid refrigerant.

In addition, the control valve unit is installed in the first supply pipe that guides the refrigerant in the gaseous phase separated by the first separation unit to the inlet of the fifth compression stage, and operates by a control signal from the control unit to open and close the first operation valve. may include

In addition, the control valve unit is installed in the second supply pipe for guiding the refrigerant in the gaseous phase separated by the second separation unit to the inlet of the fourth compression stage, and operates by a control signal from the control unit to open and close the conduit. may include more.

In addition, the control valve unit is installed in the third supply pipe for guiding the refrigerant in the gaseous phase separated by the third separation unit to the inlet of the third compression stage, and operates by a control signal from the control unit to open and close the pipeline. may include more.

In addition, the control valve unit is installed in the fourth supply pipe for guiding the gaseous refrigerant separated by the fourth separation unit to the inlet of the second compression stage, and operates by a control signal from the control unit to open and close the pipeline. may include more.

In addition, the control unit operates the fourth operation valve to block the fourth supply pipe in order to reduce the cooling capacity, and, if necessary, sequentially operates the third operation valve, the second operation valve, and the first operation valve to block the pipeline. have.

In addition, the present invention further includes a reservoir connected to the condensing unit and storing the liquid refrigerant condensed in the condensing unit, the first expansion valve unit expanding the refrigerant discharged from the reservoir, and connecting the reservoir and the gas-liquid separation unit and may be installed in the first pipe.

In addition, the second expansion valve unit includes a first valve connected to a second pipe connecting the first separation unit and the second separation unit, and a second valve connected to a third pipe connecting the second separation unit and the third separation unit; , a third valve connected to the fourth pipe connecting the third separation unit and the fourth separation unit, and a fourth valve connected to the fifth pipe connecting the fourth separation unit and the evaporator.

Since the control unit according to the present invention controls the control valve unit installed in the conduit for supplying the gas refrigerant to the compression unit having a plurality of compression stages, it is possible to easily control the cooling capacity of the refrigerating device, and to minimize the decrease in refrigeration efficiency. can do.

In addition, in the gas-liquid separation unit according to the present invention, since the blockage of the conduit for transporting the gas refrigerant from the separation unit having a low pressure to the separation unit having a high pressure is sequentially made, the partial load response of the cooling capacity can be made in stages.

In addition, since the refrigerant moving from the condensing unit to the evaporator according to the present invention expands sequentially as it passes through the separation unit of the gas-liquid separation unit made of a plurality of parts, it is possible to reduce noise during partial load operation.

In addition to the above-described effects, the specific effects of the present invention will be described together while describing specific details for carrying out the invention below.

1 is a block diagram showing the main configuration of a multi-stage compression type refrigeration apparatus according to an embodiment of the present invention.
2 is a block diagram illustrating a compression unit according to an embodiment of the present invention.
3 is a block diagram illustrating a reservoir and a gas-liquid separation unit according to an embodiment of the present invention.
4 is a block diagram illustrating a state in which the refrigerant in the gas phase separated by the gas-liquid separation unit is moved to the compression unit according to an embodiment of the present invention.
5 is a block diagram illustrating a state in which the compression unit is cooled by using the refrigerant discharged from the condensing unit according to an embodiment of the present invention.
6 is a perspective view illustrating a multi-stage compression type refrigeration apparatus according to an embodiment of the present invention.
7 is a PH diagram when the gas-liquid separation unit is fully operated according to an embodiment of the present invention.
8 is a PH diagram in a state in which the fourth separator is not operated according to an embodiment of the present invention.
9 is a PH diagram in a state in which the third and fourth separators are not operated according to an embodiment of the present invention.
10 is a PH diagram in a state in which second, third, and fourth separators are not operated according to an embodiment of the present invention.
11 is a PH diagram when the gas-liquid separation unit is not fully operated according to an embodiment of the present invention.

The above-described objects, features and advantages will be described below in detail with reference to the accompanying drawings, and accordingly, those of ordinary skill in the art to which the present invention pertains will be able to easily implement the technical idea of the present invention. In describing the present invention, if it is determined that a detailed description of a known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

Although the first, second, etc. are used to describe various elements, these elements are not limited by these terms, of course. These terms are only used to distinguish one component from other components, and unless otherwise stated, the first component may be the second component, of course.

In the following, that an arbitrary component is disposed on the "upper (or lower)" of a component or "upper (or below)" of a component means that any component is disposed in contact with the upper surface (or lower surface) of the component. Furthermore, it may mean that other components may be interposed between the component and any component disposed on (or under) the component.

Also, when it is described that a component is "connected", "coupled" or "connected" to another component, the components may be directly connected or connected to each other, but other components are "interposed" between each component. It is to be understood that “or, each component may be “connected,” “coupled,” or “connected” through another component.

Throughout the specification, unless otherwise stated, each element may be singular or plural.

As used herein, the singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as "consisting of" or "comprising" should not be construed as necessarily including all of the various components or various steps described in the specification, some of which components or some steps are It should be construed that it may not include, or may further include additional components or steps.

Throughout the specification, when “A and/or B” is used, it means A, B or A and B, unless specifically stated to the contrary, and when “C to D” is used, it means that there is no specific contrary description. Unless otherwise specified, it means that it is greater than or equal to C and less than or equal to D.

Hereinafter, a multi-stage compression type refrigeration apparatus according to an embodiment of the present invention will be described.

[Multi-stage compression refrigeration system]

1 is a block diagram showing the main configuration of a multi-stage compression type refrigeration apparatus according to an embodiment of the present invention.

As shown in FIG. 1 , a multi-stage compression refrigeration apparatus 1 according to an embodiment of the present invention includes a compression unit 10 , a condensing unit 40 , a reservoir 60 , and a first expansion valve unit ( 70 ), a gas-liquid separation unit 80 , a second expansion valve unit 90 , an evaporation unit 100 , a pipeline unit 110 , a control valve unit 130 , and a control unit 140 .

[Compression part]

2 is a block diagram illustrating a compression unit according to an embodiment of the present invention.

As shown in FIGS. 1 and 2 , the compression unit 10 can be deformed into various shapes within the technical concept in which the refrigerant is compressed at a plurality of compression stages. The compression unit 10 according to an embodiment includes a first compression unit 20 and a second compression unit 30 .

[First Compression Unit]

The first compression unit 20 is connected to the evaporator 100 through the conduit unit 110 , and after receiving the refrigerant through the evaporator 100 , various modifications are possible within the technical concept of compression at a plurality of compression stages. possible.

The first compression unit 20 according to an embodiment is installed in succession to the first compression stage 22 and the first compression stage 22 for compressing the refrigerant delivered through the evaporator 100 , and the first compression stage It may include a second compression stage 24 for re-compressing the refrigerant compressed in (22). Although it has been described that the first compression unit 20 compresses the refrigerant at two compression stages, the present invention is not limited thereto, and the first compression unit 20 according to an embodiment includes a single compression stage or three A plurality of compression stages as described above may be provided.

The gaseous refrigerant discharged from the evaporator 100 is moved to the first compression stage 22 of the first compression unit 20 to be compressed. The second compression end 24 is located at the rear (right side of FIG. 1 reference) facing the first compression end 22 . The refrigerant compressed in the first compression stage 22 is moved to the second compression stage 24 and compressed again.

[Second Compression Unit]

The second compression unit 30 is connected to the first compression unit 20, and various types of compressors may be used within the technical concept of compressing the refrigerant compressed through the first compression unit 20 at a plurality of compression stages. can The second compression unit 30 receives the refrigerant compressed by the first compression unit 20 and performs compression, and the first compression unit 20 and the second compression unit 30 are connected by a pipe-shaped conduit. .

The first compression unit 20 according to an embodiment includes two compression stages, and the second compression unit 30 includes three compression stages. However, the first compression unit 20 may include three or more compression stages, and the second compression unit 30 may also include two or four or more compression stages, and various modifications are possible.

For example, the second compression unit 30 includes a third compression end 32 , a fourth compression end 34 , and a fifth compression end 36 . The third compression stage 32, the fourth compression stage 34, and the fifth compression stage 36 are arranged in one row, and the refrigerant is compressed in order. The third compression end 32 , the fourth compression end 34 , and the fifth compression end 36 are located inside the case of the second compression unit 30 .

The third compression stage 32 compresses the refrigerant delivered through the second compression stage 24 . The fourth compression end 34 positioned at the rear of the third compression end 32 is installed in succession to the third compression end 32 , and again compresses the refrigerant compressed in the third compression end 32 . And the fifth compression stage 36 is installed successively to the fourth compression stage 34, and compresses the refrigerant compressed in the fourth compression stage 34 again.

The first compression unit 20 is provided with a first compression end 22 and a second compression end 24 for compressing the refrigerant, the first compression end 22 and the second compression end 24 are 1 It rotates by the operation of the motor provided in the compression unit 20 and compresses the refrigerant.

Also, the second compression unit 30 is provided with a third compression stage 32, a fourth compression stage 34, and a fifth compression stage 36 for compressing the refrigerant, and the third compression stage 32 and The fourth compression stage 34 and the fifth compression stage 36 rotate by the operation of a motor provided in the second compression unit 30 to compress the refrigerant.

[Condensation part]

The condensing unit 40 is connected to the compression unit 10 through a connection pipe, and the refrigerant passing through the compression unit 10 is condensed by heat exchange. The refrigerant moving from the second compression unit 30 to the inlet of the condensing unit 40 is in a vapor state, and the refrigerant passing through the condensing unit 40 exchanges heat with air or a low-temperature fluid and becomes a liquid refrigerant.

[Reservoir]

3 is a block diagram illustrating the reservoir 60 and the gas-liquid separator 80 according to an embodiment of the present invention.

1 and 3, the reservoir 60 is connected to the condensing unit 40, and has various shapes within the technical idea having a space in which the liquid refrigerant condensed in the condensing unit 40 is stored. Transformation is possible. In addition, the reservoir 60 receives the supercooled liquid refrigerant through the condensing unit 40 and stores it inside.

For example, the reservoir 60 is installed successively to the gas-liquid separation unit 80 and has a cylindrical shape. Since the reservoir 60 is formed in a cylindrical shape, even when the internal pressure is increased by the refrigerant stored inside the reservoir 60, the pressure can be easily distributed along the cylindrical shape, so that the reservoir 60 is It is possible to improve the durability of the gas-liquid separation unit 80 .

The reservoir 60 may be installed between the condensing unit 40 and the gas-liquid separating unit 80 , and installation of the reservoir 60 may be omitted in some cases. When the installation of the reservoir 60 is omitted, the refrigerant discharged from the condensing unit 40 passes through the first expansion valve unit 70 , expands, and then is supplied to the first separation unit 82 .

[Gas-liquid separator]

The gas-liquid separation unit 80 receives the refrigerant that has passed through the first expansion valve unit 70 and separates it into a liquid refrigerant and a gaseous refrigerant, and the gas-liquid refrigerant is supplied to the compression unit 10 in various ways within the technical concept. Transformation is possible.

Since the gas-liquid separation unit 80 is installed in succession to the reservoir 60 , the installation space of the reservoir 60 and the gas-liquid separation unit 80 can be reduced and the space utilization can be increased. For example, the gas-liquid separation unit 80 and the reservoir 60 may be sequentially installed inside a cylindrical case extending in a straight direction.

The gas-liquid separation unit 80 and the reservoir 60 are installed in a single case, and since the gas-liquid separation unit 80 and the reservoir 60 use the outer case in common, facility installation costs can be reduced, and a relatively narrow space Also, since the reservoir 60 and a plurality of separation units can be installed, the refrigeration efficiency can be improved.

A partition wall installed in a vertical direction is positioned between the reservoir 60 installed inside the single case and the gas-liquid separation unit 80, and a partition wall installed in the vertical direction is also installed between each separation unit provided in the gas-liquid separation unit 80. Located.

The gas-liquid separation unit 80 may be provided with a plurality of separation units for separating the transferred refrigerant into a liquid refrigerant and a gaseous refrigerant. In addition, the number of separation units provided in the gas-liquid separation unit 80 may be smaller than the number of compression stages provided in the compression unit 10 .

For example, the compression unit 10 according to the present invention is provided with five compression stages, and the gas-liquid separation unit 80 corresponding thereto is provided with four separation units. The maximum number of separation units provided in the gas-liquid separation unit 80 is a number obtained by subtracting 1 from the number of compression stages provided in the compression unit 10 .

The gas-liquid separation unit 80 according to an embodiment of the present invention includes a first separation unit 82 , a second separation unit 84 , a third separation unit 86 , and a fourth separation unit 88 .

The first separation unit 82 is installed successively to the reservoir 60 with the partition wall interposed therebetween and is connected to the first expansion valve unit 70 . Accordingly, the liquid refrigerant in the supercooled state discharged from the reservoir 60 passes through the first valve 92 , the pressure decreases and the volume moves to the inside of the first separator 82 in an expanded state.

The refrigerant moved to the inside of the first separation unit 82 is separated into a gaseous refrigerant and a liquid refrigerant. The refrigerant in the gas phase separated by the first separator 82 moves to the inlet of the fifth compression stage 36 , and the refrigerant moves from the outlet of the fourth compression stage 34 to the inlet of the fifth compression stage 36 . is moved to the fifth compression stage 36 together with the compression.

The second separation unit 84 is installed in succession to the first separation unit 82 , and separates the refrigerant transferred from the first separation unit 82 into a gaseous refrigerant and a liquid refrigerant.

The second separation unit 84 is installed in succession to the first separation unit 82 with the partition wall interposed therebetween, and receives the refrigerant passing through the first valve 92 provided in the second expansion valve unit 90 . Therefore, the liquid refrigerant discharged from the first separator 82 passes through the first valve 92 provided in the second expansion valve 90, the pressure decreases and the volume expands in the second separator ( 84) moves to the inside.

The refrigerant moved to the inside of the second separator 84 is separated into a gaseous refrigerant and a liquid refrigerant. The refrigerant in the gas phase separated by the second separator 84 moves to the inlet of the fourth compression stage 34 , and the refrigerant moves from the outlet of the third compression stage 32 to the inlet of the fourth compression stage 34 . is moved to the fourth compression stage 34 together with the compression.

The third separation unit 86 is installed in succession to the second separation unit 84 with the partition wall interposed therebetween, and receives the refrigerant passing through the second valve 94 provided in the second expansion valve unit 90 . Therefore, the liquid refrigerant discharged from the second separation unit 84 passes through the second valve 94 provided in the second expansion valve unit 90, the pressure decreases and the volume expands in the third separation unit ( 86) moves to the inside.

The refrigerant moved to the inside of the third separating unit 86 is separated into a gaseous refrigerant and a liquid refrigerant. The refrigerant in the gas phase separated by the third separation unit 86 moves to the inlet of the third compression stage 32 , and the refrigerant moves from the outlet of the second compression stage 24 to the inlet of the third compression stage 32 . is moved to the third compression end 32 together with the compression.

The fourth separation unit 88 is installed in succession to the third separation unit 86 with the partition wall interposed therebetween, and receives the refrigerant passing through the third valve 96 provided in the second expansion valve unit 90 . Accordingly, the liquid refrigerant discharged from the third separation unit 86 passes through the third valve 96 provided in the second expansion valve unit 90, the pressure decreases and the volume expands in the fourth separation unit ( 88) moves to the inside.

The refrigerant moved to the inside of the fourth separating unit 88 is separated into a gaseous refrigerant and a liquid refrigerant. The refrigerant in the gas phase separated by the fourth separator 88 moves to the inlet of the second compression stage 24 , and the refrigerant moves from the outlet of the first compression stage 22 to the inlet of the second compression stage 24 . is moved to the second compression stage 24 together with the compression.

The first separation unit 82 , the second separation unit 84 , the third separation unit 86 , and the fourth separation unit 88 constituting the reservoir 60 and the gas-liquid separation unit 80 are sequentially connected to each other in this order. It is installed in one row in a row and is located inside the single tank part.

In addition, since the gas-liquid separation unit 80 is manufactured integrally with the reservoir unit, it is possible to have a compact external configuration compared to a refrigeration device in which the gas-liquid separation unit 80 is installed next to the conventional compression unit 10 . In addition, since the gas-liquid separation unit 80 is installed in a tank shape together with the reservoir 60, the installation space of the gas-liquid separation unit 80 and the reservoir 60 is reduced. It can be installed to improve the refrigeration efficiency.

In addition, the refrigeration capacity can be remarkably improved compared to the prior art by increasing the number of separation units provided in the gas-liquid separation unit 80 . In the present invention, the refrigeration efficiency was improved by applying four separators to the five-stage refrigeration cycle.

In the existing refrigerator, there was a structural limitation in the installation space of the separation unit located above the heat exchanger. However, since the gas-liquid separation unit 80 and the reservoir 60 are installed in the form of an integrated tank, the limitation of the installation space can be solved, and the refrigeration efficiency can be improved by increasing the number of installation units of the separation unit.

[First expansion valve part]

A first separation unit 82 is installed in succession to the reservoir 60 , and the reservoir 60 and the first separation unit 82 are connected by a first pipe 111 . A first expansion valve unit 70 is installed in the first pipe 111 which is a conduit connected to the reservoir 60 , and the first expansion valve unit 70 expands the refrigerant discharged from the reservoir 60 , depressurize.

[Second expansion valve part]

The second expansion valve unit 90 is installed in a pipeline connected to the gas-liquid separation unit 80 , and various types of expansion valves may be used within the technical concept of expanding the refrigerant discharged from the gas-liquid separation unit 80 . The second expansion valve part 90 according to an embodiment of the present invention includes a first valve 92 , a second valve 94 , a third valve 96 , and a fourth valve 98 .

The first valve 92 is connected to the second pipe 112 connecting the first separation unit 82 and the second separation unit 84 , and expands the refrigerant discharged from the first separation unit 82 and depressurizes it. make it The refrigerant that has passed through the first valve 92 moves to the second separation unit 84 along the second pipe 112 .

The second valve 94 is connected to the third pipe 113 connecting the second separation unit 84 and the third separation unit 86 , and expands the refrigerant discharged from the second separation unit 84 and depressurizes it. make it The refrigerant that has passed through the second valve 94 moves to the third separation unit 86 along the third pipe 113 .

The third valve 96 is connected to the fourth pipe 114 connecting the third separation unit 86 and the fourth separation unit 88 , and expands the refrigerant discharged from the third separation unit 86 and depressurizes it. make it The refrigerant that has passed through the third valve 96 moves to the fourth separation unit 88 along the fourth pipe 114 .

The fourth valve 98 is connected to the fifth pipe 115 connecting the fourth separation unit 88 and the evaporator 100 , and expands and depressurizes the refrigerant discharged from the fourth separation unit 88 . The refrigerant that has passed through the fourth valve 98 moves to the evaporator 100 along the fifth pipe 115 .

[evaporator]

The evaporator 100 is connected to the gas-liquid separation unit 80 and the compression unit 10 through a pipe line, and within the technical idea of converting the liquid refrigerant discharged from the gas-liquid separation unit 80 into a gaseous refrigerant by heat exchange. Various types of evaporators may be used. The refrigerant passing through the fourth valve 98 passes through the evaporator 100 , becomes a low-temperature gas, and then moves to the compression unit 10 .

[Pipeline]

The conduit unit 110 connects the main components of the multi-stage compression type refrigeration apparatus 1, and various modifications are possible within the technical idea for guiding the movement of the refrigerant. For example, the conduit unit 110 includes a first pipe 111 , a second pipe 112 , a third pipe 113 , a fourth pipe 114 , a fifth pipe 115 , and a first cooling pipe 116 . and a second cooling pipe 117 , a first discharge pipe 118 , and a second discharge pipe 119 . In addition, the conduit unit 110 includes a first supply pipe 120 , a second supply pipe 122 , a third supply pipe 124 , and a fourth supply pipe connecting the gas-liquid separation unit 80 and the compression unit 10 . (126) may be further included.

The first pipe 111 is a conduit connecting the reservoir 60 and the first separation unit 82 , and the reservoir 60 and the gas-liquid separation unit 80 are integrally formed to protrude to the outside of the tank. can Alternatively, various modifications such as the reservoir 60 and the gas-liquid separation unit 80 may be installed inside the integrally formed tank. The first expansion valve 70 is installed in the first pipe 111 .

The second pipe 112 is a conduit connecting the first separation unit 82 and the second separation unit 84 , and the outside of the tank in which the first separation unit 82 and the second separation unit 84 are integrally formed. It may have a protruding shape. Alternatively, various modifications are possible, such as the first separation unit 82 and the second separation unit 84 may be installed inside the integrally formed tank. The first valve 92 is installed in the second pipe 112 .

The third pipe 113 is a conduit connecting the second separation unit 84 and the third separation unit 86, and the outside of the tank in which the second separation unit 84 and the third separation unit 86 are integrally formed. It may have a protruding shape. Alternatively, various modifications such as the second separation unit 84 and the third separation unit 86 may be installed inside the integrally formed tank. A second valve 94 is installed in the third pipe 113 .

The fourth pipe 114 is a conduit connecting the third separating part 86 and the fourth separating part 88, and the outside of the tank in which the third separating part 86 and the fourth separating part 88 are integrally formed. It may have a protruding shape. Alternatively, various modifications are possible, such as the third separation unit 86 and the fourth separation unit 88 may be installed inside the integrally formed tank. A third valve 96 is installed in the fourth pipe 114 .

The fifth pipe 115 is a conduit connecting the fourth separating part 88 and the evaporating part 100 . A second valve 94 is installed in the fifth pipe 115 .

[Control valve part]

The control valve unit 130 is installed in a plurality of pipelines for guiding the gas-phase refrigerant separated by the gas-liquid separation unit 80 to the compression unit, and is operated manually or automatically to control the movement of the refrigerant. valves can be used. The control valve unit 130 according to an embodiment includes a first operation valve 132 , a second operation valve 134 , a third operation valve 136 , and a fourth operation valve 138 .

The first operation valve 132 is installed in the first supply pipe 120 that guides the refrigerant in the gas phase separated by the first separator 82 to the inlet of the fifth compression stage, and is is operated to open and close the first supply pipe 120 .

The second operation valve 134 is installed in the second supply pipe 122 that guides the refrigerant in the gaseous phase separated by the second separator 84 to the inlet of the fourth compression stage, and responds to the control signal of the controller 140 . operated to open and close the second supply pipe 122 .

The third operation valve 136 is installed in the third supply pipe 124 for guiding the refrigerant in the gaseous phase separated by the third separating unit 86 to the inlet of the third compression stage, and receives a control signal from the control unit 140 . is operated to open and close the third supply pipe 124 .

The fourth operation valve 138 is installed in the fourth supply pipe 126 for guiding the refrigerant in the gaseous phase separated by the fourth separating unit 88 to the inlet of the second compression stage, and responds to the control signal of the controller 140. operated to open and close the fourth supply pipe 126 .

The first operation valve 132 , the second operation valve 134 , the third operation valve 136 , and the fourth operation valve 138 may be operated by manual operation, and by a control signal of the control unit 140 , It may be operated automatically.

[control unit]

The control unit 140 may use various types of control devices within the technical concept for controlling the operation of the control valve unit 130 . The control unit 140 according to an embodiment blocks the conduit connected to the separation unit sequentially from the separation unit having the lowest pressure toward the separation unit having the highest pressure, so that the cooling capacity can be adjusted.

The control unit 140 according to an embodiment operates the fourth operation valve 138 to reduce the cooling capacity to block the fourth supply pipe 126 , and, if necessary, sequentially operate the third operation valve 136 and The second operation valve 134 and the first operation valve 132 may be operated to block the pipeline.

[Cooling of the motor]

5 is a block diagram illustrating a state in which the compression unit 10 is cooled by using the refrigerant discharged from the condensing unit 40 according to an embodiment of the present invention.

1 and 5, the first cooling pipe 116 is connected to the condensing unit 40 and the first compression unit 20, and a portion of the refrigerant condensed in the condensing unit 40 is transferred to the first It is supplied to the compression unit 20 . One side of the first discharge pipe 118 is connected to the first compression unit 20 , and the other side is connected to the fourth pipe 114 or the fourth separation unit 88 . Alternatively, since the first cooling pipe 116 and the first discharge pipe 118 are connected, the refrigerant can be moved more easily.

The refrigerant that has cooled the motor of the first compression unit 20 moves to the fourth pipe 114 along the first discharge pipe 118, and then together with the refrigerant that has passed through the third valve 96, the fourth separation unit ( 88) can be supplied. Alternatively, the refrigerant cooling the motor of the first compression unit 20 may be moved along the first discharge pipe 118 and directly moved to the inside of the fourth separation unit 88 .

The fourth pipe 114 is connected to the fourth separation unit 88 , and the refrigerant passing through the third valve 96 expands and becomes a low pressure and low temperature state. Therefore, when the first discharge pipe 118 is connected to the fourth separation unit 88 or the fourth pipe 114, the refrigerant moving along the first discharge pipe 118 and the first cooling pipe 116 is also expanded. the temperature goes down

When the first discharge pipe 118 is connected to the fourth separation unit 88 or the fourth pipe 114, the motor provided in the first compression unit 20 is cooled by the refrigerant, and the surface temperature of the motor is about 15°C to 20°C. Therefore, since the motor provided in the first compression unit 20 is cooled above the dew-condensing temperature, it is possible to prevent dew condensation on the outside of the motor, and to prevent motor failure due to dew condensation to prevent an increase in maintenance costs. can

If the first discharge pipe 118 is connected to a separation unit other than the fourth separation unit 88 , the internal pressure of the first compression unit 20 increases. As the internal pressure of the first compression unit 20 increases, the density of the fluid inside the first compression unit 20 increases. Accordingly, a pressure loss of the first compression unit 20 is generated due to an increase in friction loss inside the motor, and a problem occurs that the efficiency of the motor is lowered. In order to solve this problem, the first discharge to the fourth separation unit 88 or the fourth pipe 114 connected to the fourth separation unit 88, which can prevent a condensation problem while having a relatively low pressure compared to other separation units. A pipe 118 is connected.

The second cooling pipe 117 is connected to the condensing unit 40 and the second compression unit 30 , and supplies a portion of the refrigerant condensed in the condensing unit 40 to the second compression unit 30 . One side of the second discharge pipe 119 is connected to the second compression unit 30 , and the other side is connected to the fourth pipe 114 or the fourth separation unit 88 . Alternatively, since the second cooling pipe 117 and the second discharge pipe 119 are connected, the refrigerant can be moved more easily.

The refrigerant that has cooled the motor of the second compression unit 30 moves to the fourth pipe 114 along the second discharge pipe 119, and then together with the refrigerant that has passed through the third valve 96, the fourth separation unit ( 88) can be supplied. Alternatively, the refrigerant cooled by the motor of the second compression unit 30 may be moved along the second discharge pipe 119 to move directly to the inside of the fourth separation unit 88 .

The fourth pipe 114 is connected to the fourth separation unit 88 , and the refrigerant passing through the third valve 96 expands and becomes a low pressure and low temperature state. Therefore, when the second discharge pipe 119 is connected to the fourth separation unit 88 or the fourth pipe 114, the refrigerant moving along the second discharge pipe 119 and the second cooling pipe 117 is also expanded. the temperature goes down

When the second discharge pipe 119 is connected to the fourth separation unit 88 or the fourth pipe 114, the motor provided in the second compression unit 30 is cooled by the refrigerant, and the surface temperature of the motor is about 15°C to 20°C. Therefore, since the motor provided in the second compression unit 30 is cooled above the dew-condensing temperature, it is possible to prevent dew condensation on the outside of the motor, and to prevent motor failure due to dew condensation, thereby preventing an increase in maintenance costs. can

If the second discharge pipe 119 is connected to a separation unit other than the fourth separation unit 88 , the internal pressure of the second compression unit 30 increases. As the internal pressure of the second compression unit 30 increases, the density of the fluid inside the second compression unit 30 increases. Accordingly, a pressure loss of the second compression unit 30 is generated due to an increase in friction loss inside the motor, and a problem occurs that the efficiency of the motor is lowered. In order to solve this problem, the second discharge to the fourth separation unit 88 or the fourth pipe 114 connected to the fourth separation unit 88, which can prevent condensation while having a relatively low pressure compared to other separation units. A pipe 119 is connected.

[Movement of gas-phase refrigerant separated from the gas-liquid separator]

4 is a block diagram illustrating a state in which the refrigerant in the gas phase separated by the gas-liquid separation unit 80 is moved to the compression unit 10 according to an embodiment of the present invention.

1 and 4 , one side of the first supply pipe 120 is connected to the first separation unit 82 and the other side is connected to the inlet of the fifth compression end 36 . Therefore, after the refrigerant in the liquid phase and the refrigerant in the gas phase are separated by the first separator 82 , the refrigerant in the gas phase is moved to the inlet of the fifth compression stage 36 along the first supply pipe 120 and then compressed by the fourth Compression is performed in the fifth compression stage 36 together with the refrigerant compressed in the stage 34 .

One side of the second supply pipe 122 is connected to the second separation unit 84 , and the other side is connected to the inlet of the fourth compression end 34 . Therefore, after being separated into a liquid refrigerant and a gaseous refrigerant in the second separating unit 84 , the gaseous refrigerant is moved to the inlet of the fourth compression stage 34 along the second supply pipe 122 and then compressed by the third Compression is performed in the fourth compression stage 34 together with the refrigerant compressed in the stage 32 .

One side of the third supply pipe 124 is connected to the third separation unit 86 , and the other side is connected to the inlet of the third compression end 32 . Therefore, after being separated into a liquid refrigerant and a gaseous refrigerant in the third separating unit 86 , the gaseous refrigerant is moved to the inlet of the third compression stage 32 along the third supply pipe 124 and then compressed by the second Compression is performed in the third compression stage 32 together with the refrigerant compressed in the stage 24 .

One side of the fourth supply pipe 126 is connected to the fourth separation unit 88 , and the other side is connected to the inlet of the second compression end 24 . Therefore, after being separated into a liquid refrigerant and a gaseous refrigerant in the fourth separating unit 88 , the gaseous refrigerant is moved to the inlet of the second compression stage 24 along the fourth supply pipe 126 and then first compressed Compression is performed in the second compression stage 24 together with the refrigerant compressed in the stage 22 .

6 is a perspective view showing a multi-stage compression type refrigeration apparatus 1 according to an embodiment of the present invention.

As shown in FIG. 6 , the reservoir 60 and the gas-liquid separation unit 80 are installed in a straight direction, and are located inside the tank of a single case shape. Therefore, since the installation space is significantly smaller than that in which the reservoir 60 and the gas-liquid separation unit 80 are separately installed, the multi-stage compression type refrigeration apparatus 1 can be installed in various spaces.

A tank-shaped evaporation unit 100 is installed on the side of the tank including the reservoir 60 and the gas-liquid separation unit 80 . The tank according to an embodiment of the present invention refers to a large barrel for containing a fluid such as refrigerant, water, gas, oil, and the like, and the tank has a cylindrical case.

The compression unit 10 is positioned above the tank-shaped structure including the evaporator or reservoir 60 and the gas-liquid separation unit 80 . The compression unit 10 includes a first compression unit 20 and a second compression unit 30 , and the first compression unit 20 and the second compression unit 30 move the refrigerant through a pipe-shaped conduit. this is done

[Operation of the present invention]

Hereinafter, the operating state of the multi-stage compression type refrigeration apparatus 1 according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

7 is a P-H diagram of the multi-stage compression type refrigeration apparatus 1 according to an embodiment of the present invention.

1 and 7, the refrigerant compressed in the first compression stage 22 of the first compression unit 20 is moved to the second compression stage 24 for compression. And the refrigerant compressed in the second compression stage 24 is moved to the third compression stage 32 and compressed. And the refrigerant compressed in the third compression stage 32 is moved to the fourth compression stage 34 to be compressed. And the refrigerant compressed in the fourth compression stage 34 is moved to the fifth compression stage 36 to be compressed. The refrigerant compressed in the compression unit 10 is in a saturated vapor state.

The gaseous refrigerant discharged from the second compression unit 30 moves to the condensing unit 40 and exchanges heat with air or other refrigerant or fluid to become a liquid refrigerant.

The refrigerant discharged from the condensing unit 40 is moved to and stored in the reservoir 60 . Then, the refrigerant stored in the reservoir 60 passes through the first expansion valve unit 70 and moves to the inside of the first separation unit 82 in a state where the pressure is decreased and the expansion is made.

The first separator 82 separates the refrigerant into a vapor phase and a liquid refrigerant, and the gaseous refrigerant enters the inlet of the fifth compression stage 36 through the first supply pipe 120 and the first operation valve 132 . Move. The gaseous refrigerant moved to the inlet of the fifth compression stage 36 is compressed at the fifth compression stage 36 together with the refrigerant discharged through the outlet of the fourth compression stage 34 .

The liquid refrigerant stored in the first separation unit 82 passes through the first valve 92 provided in the second expansion valve unit 90 and expands while the pressure decreases. The refrigerant stored in the first separation unit 82 passes through the first valve 92 and moves to the inside of the second separation unit 84 .

The second separator 84 separates the refrigerant into a vapor phase and a liquid refrigerant, and the gaseous refrigerant enters the inlet of the fourth compression stage 34 through the second supply pipe 122 and the second operation valve 134 . Move. The gaseous refrigerant moved to the inlet of the fourth compression stage 34 is compressed at the fourth compression stage 34 together with the refrigerant discharged through the outlet of the third compression stage 32 .

The liquid refrigerant stored in the second separation unit 84 passes through the second valve 94 provided in the second expansion valve unit 90 and expands while the pressure decreases. The refrigerant stored in the second separation unit 84 passes through the second valve 94 and moves to the inside of the third separation unit 86 .

The third separator 86 separates the refrigerant into a vapor phase and a liquid refrigerant, and the gaseous refrigerant enters the inlet of the third compression stage 32 through the third supply pipe 124 and the third operation valve 136 . Move. The gaseous refrigerant moved to the inlet of the third compression stage 32 is compressed at the third compression stage 32 together with the refrigerant discharged through the outlet of the second compression stage 24 .

The liquid refrigerant stored in the third separation unit 86 passes through the third valve 96 provided in the second expansion valve unit 90 and expands while the pressure decreases. The refrigerant stored in the third separation unit 86 passes through the third valve 96 and moves to the inside of the fourth separation unit 88 .

In the fourth separation unit 88, the refrigerant in the gas phase and the refrigerant in the liquid phase are separated, and the refrigerant in the gaseous phase is directed to the inlet of the second compression stage 24 through the fourth supply pipe 126 and the fourth operation valve 138. Move. The gaseous refrigerant moved to the inlet of the second compression stage 24 is compressed at the second compression stage 24 together with the refrigerant discharged through the outlet of the first compression stage 22 .

The liquid refrigerant discharged from the fourth separation unit 88 passes through the fourth valve 98 , and the pressure is lowered and expanded at the same time, and the temperature is lowered. The refrigerant that has passed through the fourth valve 98 moves to the evaporator 100 along the fifth pipe 115 and exchanges heat with the fluid supplied to the consumer to become a gaseous refrigerant.

The refrigerant that has passed through the evaporator 100 is moved to the compression unit 10 again to be compressed.

As shown in FIG. 5 , the refrigerant passing through the condensing unit 40 is a liquid refrigerant, and a portion of the refrigerant is supplied to the first and second compression units 20 and 30 .

Some of the refrigerant discharged from the condensing unit 40 moves along the first cooling pipe 116 and expands while the temperature decreases. This refrigerant moves to the first compression unit 20 to cool the first compression unit 20 and then to the fourth pipe 114 through the first discharge pipe 118 . In addition, some of the refrigerant discharged from the condensing unit 40 is moved to the second compression unit 30 along the second cooling pipe 117 to cool the second compression unit 30 and then to the second discharge pipe 119 . moves to the fourth pipe 114 through

The refrigerant moved to the fourth pipe 114 is moved to the fourth separator 88 together with the refrigerant that has passed through the third valve 96 to be separated into a gaseous refrigerant and a liquid refrigerant.

In the P-H diagram shown in FIG. 7 , the horizontal axis is enthalpy (H), and the vertical axis is pressure (P). And C represents the total cooling capacity.

8 is a P-H diagram in a state in which the fourth separating unit 88 is not operated according to an embodiment of the present invention.

1 and 8, during partial load operation of the multi-stage compression type refrigeration apparatus 1, the control unit 140 has the lowest pressure among the four separation units provided in the gas-liquid separation unit 80. By stopping the operation of the fourth separation unit 88, the cooling capacity of the multi-stage compression type refrigeration system 1 is reduced.

In order to stop the operation of the fourth separation unit 88, the control unit 140 sends a control signal to the fourth operation valve 138 to operate the fourth operation valve 138 in the off mode, so that the fourth supply pipe 126 is operated. close the Accordingly, the movement of the refrigerant in the gas phase separated by the fourth separating unit 88 between the first compression end 22 and the second compression end 24 through the fourth supply pipe 126 is stopped.

Since movement of the refrigerant in the gas phase through the fourth supply pipe 126 is blocked, the third separation unit 86 functions as the existing fourth separation unit 88 . In addition, since the fourth separation unit 88 is not operated in the multi-stage compression type refrigeration system 1 , a partial load operation with reduced cooling capacity may be performed.

When the fourth separating unit 88 is not operated, the cooling capacity is reduced by the first reduced cooling capacity (R1), and the first cooling capacity by subtracting the first reduced cooling capacity (R1) from the total cooling capacity (C) ( As C1), the multi-stage compression type refrigeration system 1 is operated.

9 is a P-H diagram in a state in which the third and fourth separators are not operated according to an embodiment of the present invention.

1 and 9, during the partial load operation of the multi-stage compression type refrigeration apparatus 1, the control unit 140 has the lowest pressure among the four separation units provided in the gas-liquid separation unit 80. The operation of the fourth separation unit 88 and the third separation unit 86 having the lowest pressure among the separation units other than the fourth separation unit 88 is sequentially stopped to obtain a multi-stage compression type refrigeration system (1) reduce the cooling capacity of

In order to stop the operation of the fourth separation unit 88, the control unit 140 sends a control signal to the fourth operation valve 138 to operate the fourth operation valve 138 in the off mode, so that the fourth supply pipe 126 is operated. close the Accordingly, the movement of the refrigerant in the gas phase separated by the fourth separating unit 88 between the first compression end 22 and the second compression end 24 through the fourth supply pipe 126 is stopped.

In order to stop the operation of the third separation unit 86, the control unit 140 sends a control signal to the third operation valve 136 to operate the third operation valve 136 in the off mode, so that the third supply pipe 124 is operated. close the Therefore, the operation of moving the refrigerant in the gas phase separated by the third separation unit 86 between the second compression end 24 and the third compression end 32 through the third supply pipe 124 is stopped.

Since movement of the refrigerant in the gas phase through the fourth supply pipe 126 and the third supply pipe 124 is blocked, the second separation unit 84 is separated from the existing fourth separation unit 88 and the third separation unit 86 . will play a role In addition, the multi-stage compression refrigeration system 1 may perform a partial load operation with a reduced secondary cooling capacity in which the fourth separating unit 88 and the third separating unit 86 are not operated.

When the third separating unit 86 and the fourth separating unit 88 are not operated, the cooling capacity is reduced by the second reduced cooling capacity (R2), and the second reduced cooling capacity (R2) from the total cooling capacity (C) ) minus the second cooling capacity (C2), the multi-stage compression type refrigeration system (1) is operated.

10 is a P-H diagram in a state in which second, third, and fourth separators are not operated according to an embodiment of the present invention.

As shown in FIGS. 1 and 10 , during partial load operation of the multi-stage compression type refrigeration apparatus 1 , the control unit 140 has the lowest pressure among the four separation units provided in the gas-liquid separation unit 80 . The fourth separation unit 88 and the third separation unit 86 having the lowest pressure among the separation units other than the fourth separation unit 88, and the fourth separation unit 88 and the third separation unit 86 ), the operation of the second separation unit 84 having the lowest pressure among other separation units is sequentially stopped to reduce the cooling capacity of the multi-stage compression type refrigeration device 1 .

In order to stop the operation of the fourth separation unit 88, the control unit 140 sends a control signal to the fourth operation valve 138 to operate the fourth operation valve 138 in the off mode, so that the fourth supply pipe 126 is operated. close the Accordingly, the movement of the refrigerant in the gas phase separated by the fourth separating unit 88 between the first compression end 22 and the second compression end 24 through the fourth supply pipe 126 is stopped.

In order to stop the operation of the third separation unit 86, the control unit 140 sends a control signal to the third operation valve 136 to operate the third operation valve 136 in the off mode, so that the third supply pipe 124 is operated. close the Accordingly, the movement of the refrigerant in the gas phase separated by the third separation unit 86 between the second compression end 24 and the third compression end 32 through the third supply pipe 124 is stopped.

In order to stop the operation of the second separation unit 84 , the control unit 140 sends a control signal to the second operation valve 134 to operate the second operation valve 134 in the off mode, so that the second supply pipe 122 . close the Accordingly, the movement of the refrigerant in the gas phase separated by the second separator 84 between the third compression end 32 and the fourth compression end 34 through the second supply pipe 122 is stopped.

Since the movement of the refrigerant in the gas phase through the fourth supply pipe 126, the third supply pipe 124, and the second supply pipe 122 is blocked, the first separating unit 82 is separated from the existing fourth separating unit 88. It serves as the third separating part 86 and the second separating part 84 . In addition, the multi-stage compression type refrigeration system 1 can perform partial load operation with reduced tertiary cooling capacity in which the second separation unit 84, the third separation unit 86, and the fourth separation unit 88 do not operate. have.

When the second separation unit 84, the third separation unit 86, and the fourth separation unit 88 do not operate, the cooling capacity is reduced by the third reduced cooling capacity R3, and the total cooling capacity (C) The multi-stage compression type refrigeration device 1 is operated with the third cooling capacity C3 minus the third reduced cooling capacity R3 from .

11 is a P-H diagram when the gas-liquid separator 80 is not fully operated according to an embodiment of the present invention.

As shown in FIGS. 1 and 11 , during partial load operation of the multi-stage compression type refrigeration system 1 , the control unit 140 has the lowest pressure among the four separation units provided in the gas-liquid separation unit 80 . The operation of the first separation unit 82 having the highest pressure in the fourth separation unit 88 is sequentially stopped to reduce the cooling capacity of the multi-stage compression type refrigeration device 1 .

First, in order to stop the operation of the fourth separation unit 88, the control unit 140 sends a control signal to the fourth operation valve 138 to operate the fourth operation valve 138 in the off mode, so the fourth supply pipe 126 ) is closed. Accordingly, the movement of the refrigerant in the gas phase separated by the fourth separating unit 88 between the first compression end 22 and the second compression end 24 through the fourth supply pipe 126 is stopped.

And in order to stop the operation of the third separation unit 86, the control unit 140 sends a control signal to the third operation valve 136 to operate the third operation valve 136 in the off mode, so that the third supply pipe 124 ) is closed. Accordingly, the movement of the refrigerant in the gas phase separated by the third separation unit 86 between the second compression end 24 and the third compression end 32 through the third supply pipe 124 is stopped.

And in order to stop the operation of the second separation unit 84, the control unit 140 sends a control signal to the second operation valve 134 to operate the second operation valve 134 in the off mode, so that the second supply pipe 122 ) is closed. Accordingly, the movement of the refrigerant in the gas phase separated by the second separator 84 between the third compression end 32 and the fourth compression end 34 through the second supply pipe 122 is stopped.

And in order to stop the operation of the first separation unit 82, the control unit 140 sends a control signal to the first operation valve 132 to operate the first operation valve 132 in the off mode, so that the first supply pipe 120 ) is closed. Accordingly, the movement of the refrigerant in the gas phase separated by the first separator 82 between the fourth compression end 34 and the fifth compression end 36 through the first supply pipe 120 is stopped.

Since movement of the refrigerant in the gas phase through the fourth supply pipe 126, the third supply pipe 124, the second supply pipe 122, and the first supply pipe 120 is blocked, the gas-liquid separator 80 is not operated. can not do it. And since the refrigerant discharged from the condensing unit 40 is directly transferred to the evaporator 100 , the multi-stage compression type refrigeration device 1 has a fourth separation unit 88 , a third separation unit 86 , and a second separation unit. Partial load operation with reduced quaternary cooling capacity in which 84 and the first separation unit 82 are not operated can be performed.

When the fourth separation unit 88, the third separation unit 86, the second separation unit 84, and the first separation unit 82 do not operate, the cooling capacity is reduced by the fourth reduced cooling capacity R4. and the multi-stage compression type refrigeration device 1 is operated with the fourth cooling capacity (C4) obtained by subtracting the fourth reduced cooling capacity (R4) from the total cooling capacity (C).

Therefore, the P-H diagram shown in FIG. 11 has the same shape as the P-H diagram of a refrigeration system using a single-stage compressor.

In the normal operation of the multi-stage compression refrigeration apparatus 1 according to an embodiment of the present invention, the cooling capacity is set to the total cooling capacity (C). In addition, the reduced cooling capacity during partial load operation in which the primary cooling capacity is reduced is referred to as a first reduced cooling capacity (R1). In addition, the reduced cooling capacity during partial load operation in which the secondary cooling capacity is reduced is referred to as a second reduced cooling capacity (R2). In addition, the reduced cooling capacity during partial load operation in which the tertiary cooling capacity is reduced is referred to as a third reduced cooling capacity (R3). In addition, the reduced cooling capacity during partial load operation in which the fourth cooling capacity is reduced is referred to as the fourth reduced cooling capacity (R4).

In this case, the value of the reduced cooling capacity during partial load operation has a relationship of R1<R2<R3<R4.

The control unit 140 includes the fourth separating unit 88 , the third separating unit 86 , the third separating unit 86 , and the first separating unit 82 in the order of the conduit unit 110 through which the gaseous refrigerant is moved. By closing the , it is possible to easily control the low load capacity of the multi-stage compression type refrigeration system (1).

<185> In the present invention, partial load operation may be possible using the multi-stage gas-liquid separation unit 80 of a large-capacity air-cooled chiller using a multi-stage compressor. And, in the prior art, the refrigerant moves from the condenser to the evaporator by using the high-temperature gas bypass, so the flow velocity in the pipe is fast and there is a problem that a large noise is generated. Therefore, it is effective in reducing noise even during partial load operation of the multi-stage compression type refrigeration system (1).

In the conventional refrigeration system, the gas-liquid separator 80 only serves to separate the condensed refrigerant into a liquid phase and a gas phase, but in the present invention, a pipeline 110 connecting the gas-liquid separator 80 and the compression part 10 It is possible to sequentially reduce the cooling capacity because it closes sequentially and operates only as a part of the expansion line.

[Effect Description]

As described above, according to an embodiment of the present invention, the control valve unit 130 is installed in the conduit unit 110 for supplying the gas refrigerant to the compression unit 10 having a plurality of compression stages, the control unit 140 is provided. control, it is possible to easily control the cooling capacity of the refrigeration system, and it is possible to minimize the decrease in refrigeration efficiency. In addition, since the gas-liquid separation unit 80 sequentially blocks the gas refrigerant from the separation unit having a low pressure toward the separation unit having a high pressure, the response to the partial load of the cooling capacity is performed step by step can be done In addition, since the refrigerant moving from the condensing unit 40 to the evaporating unit 100 passes through the separation unit of the gas-liquid separation unit 80 made of a plurality and expands in turn, noise can be reduced during partial load operation.

In addition, since the gas-liquid separation unit 80 is installed successively to the reservoir 60, and the gas-liquid separation unit 80 and the reservoir 60 are integrally installed in a single case, the space in which the gas-liquid separation unit 80 is installed is reduced. It can be minimized and the space utilization can be increased.

In addition, when the gas-liquid separation device of the existing external tank shape is applied, the size of the entire refrigeration system and the complexity of the pipe structure increase. Because it has the form of , it can solve the space constraint

In addition, since a plurality of separation units provided in the gas-liquid separation unit 80 are installed one after another and are installed adjacent to the reservoir 60, the length of the pipe used for transferring the refrigerant is minimized to reduce installation and maintenance costs. can That is, the gas-liquid separator installed in the conventional refrigeration system is installed side by side next to the compressor, and a pipe installation operation is required to transport the liquid refrigerant and the air refrigerant to the evaporator and the compressor, respectively. However, in the present invention, the structure of the pipe for transferring the liquid refrigerant is simple, and the installation length of the pipe is reduced compared to the prior art, so that the installation space of the pipe part 110 can be reduced. In addition, since the reservoir 60 integrated gas-liquid separation unit 80 is installed, the installation of the conduit unit 110 around the compression unit 10 is simplified and maintenance work can be easily performed.

In addition, a plurality of gas-liquid separation units 80 are sequentially installed in proportion to the number of compression stages provided in the compression unit 10 , and after separating the refrigerant into gas and liquid, the gaseous refrigerant is transferred to the compression unit 10 . Therefore, the refrigeration efficiency can be improved.

In addition, in the present invention, it is possible to control the cooling capacity by using four separate parts applied to the five-stage refrigeration cycle. In addition, since the present invention reduces the decrease in refrigeration efficiency by controlling the number of operating separation units, it may be possible to cope with a low load.

As described above, the present invention has been described with reference to the illustrated drawings, but the present invention is not limited by the embodiments and drawings disclosed in the present specification. It is obvious that variations can be made. In addition, although the effects according to the configuration of the present invention are not explicitly described and described while describing the embodiments of the present invention, it is natural that the effects predictable by the configuration should also be recognized.

1: Multi-stage compression refrigeration system
10: compression unit 20: first compression unit 22: first compression end 24: second compression end
30: second compression unit 32: third compression stage 34: fourth compression stage 36: fifth compression stage
40: condensing unit
60: reserve
70: first expansion valve unit
80: gas-liquid separation unit 82: first separation unit 84: second separation unit 86: third separation unit 88: fourth separation unit
90: second expansion valve part 92: first valve 94: second valve 96: third valve 98: fourth valve
100: evaporator
110: Pipe part 111: First pipe 112: Second pipe 113: Third pipe 114: Fourth pipe 115: Fifth pipe 116: First cooling pipe 117: Second cooling pipe 118: First discharge pipe 119: Second 2 discharge pipe 120: first supply pipe 122: second supply pipe 124: third supply pipe 126: fourth supply pipe
C: Total cooling capacity
R1: First reduced cooling capacity C1: First cooling capacity
R2: Second reduced cooling capacity C2: Second cooling capacity
R3: 3rd reduced cooling capacity C3: 3rd cooling capacity
R4: 4th reduced cooling capacity C4: 4th cooling capacity

Claims (15)

a compression unit that compresses the refrigerant at a plurality of compression stages;
a condensing unit connected to the compression unit and condensing the refrigerant passing through the compression unit by heat exchange;
a first expansion valve unit installed in a conduit for guiding the movement of the refrigerant discharged from the condensing unit and expanding the refrigerant;
a gas-liquid separation unit having a plurality of separation units, receiving the refrigerant that has passed through the first expansion valve unit, separating the liquid refrigerant and the gaseous refrigerant, and supplying the gaseous refrigerant to the compression unit;
a second expansion valve part installed in a pipeline connected to the gas-liquid separator and expanding the refrigerant discharged from the gas-liquid separator;
a control valve unit installed in a plurality of conduits for guiding the gas-phase refrigerant separated by the gas-liquid separation unit to the compression unit, and controlling the movement of the refrigerant; and
Includes; a control unit for controlling the operation of the control valve unit;
The gas-liquid separation unit is provided with a plurality of separation units for separating the transferred refrigerant into a liquid refrigerant and a gaseous refrigerant,
The control unit controls the control valve unit to block the pipe line connected to the separation unit sequentially from the separation unit having the lowest pressure toward the separation unit having the highest pressure, thereby reducing the cooling capacity.
delete According to claim 1,
The number of separation units provided in the gas-liquid separation unit is smaller than the number of compression stages provided in the compression unit.
delete According to claim 1,
The compression unit may include: a first compression unit for compressing the refrigerant delivered through the evaporation unit at a plurality of compression stages; and
and a second compression unit connected to the first compression unit and compressing the refrigerant compressed through the first compression unit at a plurality of compression stages.
6. The method of claim 5,
The first compression unit may include: a first compression stage for compressing the refrigerant delivered through the evaporation unit; and
A multi-stage compression type refrigeration system comprising a; a second compression stage installed in succession to the first compression stage and for re-compressing the refrigerant compressed in the first compression stage.
7. The method of claim 6,
The second compression unit may include: a third compression stage for compressing the refrigerant delivered through the second compression stage;
a fourth compression stage installed consecutively to the third compression stage and for re-compressing the refrigerant compressed in the third compression stage; and
A multi-stage compression type refrigeration system comprising a; a fifth compression stage installed in succession to the fourth compression stage and re-compressing the refrigerant compressed in the fourth compression stage.
8. The method of claim 7,
The gas-liquid separation unit may include: a first separation unit connected to the first expansion valve unit;
a second separation unit installed in succession to the first separation unit and separating the refrigerant transferred from the first separation unit into a gaseous refrigerant and a liquid refrigerant;
a third separation unit installed in succession to the second separation unit and configured to separate the refrigerant transferred from the second separation unit into a gaseous refrigerant and a liquid refrigerant; and
and a fourth separation unit installed in succession to the third separation unit and configured to separate the refrigerant transferred from the third separation unit into a gaseous refrigerant and a liquid refrigerant.
9. The method of claim 8,
The control valve unit is installed in a first supply pipe that guides the refrigerant in the gaseous phase separated by the first separation unit to the inlet of the fifth compression stage, and operates by a control signal from the control unit to open and close the conduit. A multi-stage compression type refrigeration system comprising: an operation valve.
10. The method of claim 9,
The control valve unit is installed in a second supply pipe that guides the gaseous refrigerant separated by the second separation unit to the inlet of the fourth compression stage, and operates by a control signal from the control unit to open and close the conduit. Multi-stage compression type refrigeration system further comprising an operation valve.
11. The method of claim 10,
The control valve unit is installed in a third supply pipe that guides the refrigerant in the gas phase separated by the third separation unit to the inlet of the third compression stage, and is operated by a control signal from the control unit to open and close the pipeline. Multi-stage compression type refrigeration system further comprising an operation valve.
12. The method of claim 11,
The control valve unit is installed in a fourth supply pipe for guiding the gaseous refrigerant separated by the fourth separation unit to the inlet of the second compression stage, and is operated by a control signal from the control unit to open and close the pipeline. Multi-stage compression type refrigeration system further comprising an operation valve.
13. The method of claim 12,
The control unit operates the fourth operation valve to block the fourth supply pipe in order to reduce the cooling capacity, and sequentially operates the third operation valve, the second operation valve, and the first operation valve as necessary. A multi-stage compression type refrigeration system that blocks the pipeline.
According to claim 1,
It further includes; a reservoir connected to the condensing unit to store the liquid refrigerant condensed in the condensing unit,
The first expansion valve unit expands the refrigerant discharged from the reservoir, and is installed in a first pipe connecting the reservoir and the gas-liquid separator.
9. The method of claim 8,
The second expansion valve unit may include: a first valve connected to a second pipe connecting the first separation unit and the second separation unit;
a second valve connected to a third pipe connecting the second separation unit and the third separation unit;
a third valve connected to a fourth pipe connecting the third separating part and the fourth separating part; and
and a fourth valve connected to a fifth pipe connecting the fourth separating unit and the evaporating unit.

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