KR20130086661A - A cooling system - Google Patents

Abstract

The present invention relates to a cooling system.
In the cooling system according to an embodiment of the present invention, a compressor for compressing a refrigerant; A heat exchanger for condensing the refrigerant compressed by the compressor; An oil separator provided at an inlet side of the heat exchanger and separating oil or some refrigerant from the high pressure refrigerant compressed by the compressor; A bypass passage for bypassing the oil or refrigerant separated by the oil separator to an inlet side of the compressor; And a backflow prevention device provided at an outlet side or the bypass flow path of the oil separator and preventing the refrigerant at the outlet side of the compressor from flowing back into the bypass flow path when the compressor is turned off.

Description

Cooling system {A cooling system}

The present invention relates to a cooling system.

The cooling system refers to a system that generates and supplies cold air in order to cool a predetermined storage compartment. The cooling system includes a refrigeration system and a refrigeration system that are divided according to the set temperature of the storage compartment. The refrigeration system is used for cold storage of the article, the refrigeration system can be used for freezing storage of the article.

The refrigerating system is such that refrigeration of articles and the like is performed in the first predetermined space by the refrigerant flowing through the heat exchange cycle and the heat exchange in the outdoor air space, and the heat exchange between the refrigerant and the first predetermined space. In the refrigeration system, refrigeration of articles or the like is performed in the second predetermined space by heat exchange between the refrigerant flowing in the heat exchange cycle and the outdoor air, and heat exchange between the refrigerant and the second predetermined space.

The cooling system includes a compressor for compressing a refrigerant, a condenser for condensing the refrigerant compressed by the compressor, an expansion device for reducing the refrigerant, and an evaporator for evaporating the refrigerant to generate cold air.

On the other hand, such a cooling system can be connected to an air conditioning system and operated as a complex system. The air conditioning system is used for driving a refrigerant cycle to harmonize, for example, cool or heat a predetermined space. The refrigerant circulating in the cooling system and the refrigerant circulating in the air conditioning system may be exchanged with each other, and in this process, the capacity of one of the cooling system and the air conditioning system may be used in another system.

According to the conventional cooling system, when a system OFF command is input during the operation of the cooling system, the compressor is turned off and the circulation of the refrigerant is stopped.

On the other hand, when the operation of the compressor is OFF, since the discharge pressure of the compressor is higher than the inlet pressure of the compressor, the discharge refrigerant of the compressor is bypassed to the inlet side of the compressor due to the pressure difference.

When the refrigerant is bypassed to the inlet side of the compressor, when the cooling system is operated again, there is a problem that it takes a long time to recompress the refrigerant and cool the storage compartment.

That is, as shown in FIG. 1, when the operation of the cooling system is stopped, the discharge pressure of the compressor, that is, the high pressure P _H is lowered, and the temperature of the storage compartment rises rapidly, thereby increasing the evaporation pressure P _L (low pressure). The phenomenon in which the pressure difference between the high pressure and the low pressure of the refrigerant cycle is reduced (flat pressure) occurs.

In this state, even when the cooling system is operated again, it takes a long time to reach the normal pressure range of the refrigerant cycle with a pressure difference between high and low pressure, and accordingly, the power consumption increases as the operating rate of the system increases. There was a problem.

In order to solve this problem, an object of the present invention is to provide a cooling system in which a refrigerant pressure is formed in an appropriate range when the system is turned off.

In the cooling system according to an embodiment of the present invention, a compressor for compressing a refrigerant; A heat exchanger for condensing the refrigerant compressed by the compressor; An oil separator provided at an inlet side of the heat exchanger and separating oil or some refrigerant from the high pressure refrigerant compressed by the compressor; A bypass passage for bypassing the oil or refrigerant separated by the oil separator to an inlet side of the compressor; And a backflow prevention device provided at an outlet side or the bypass flow path of the oil separator and preventing the refrigerant at the outlet side of the compressor from flowing back into the bypass flow path when the compressor is turned off.

According to another aspect of the present invention, there is provided a cooling system comprising: a cooling system performing heat exchange with an air conditioning unit including an air conditioning compressor and a cascade heat exchanger, the compressor compressing a cooling refrigerant; An oil separator for separating oil from the refrigerant compressed by the compressor; A bypass flow passage for bypassing the oil separated by the oil separator to an inlet side of the plurality of compressors; A condenser for condensing the refrigerant passing through the oil separator; An expansion device for depressurizing the refrigerant condensed in the condenser; An evaporator for evaporating the refrigerant passing through the expansion device and supplying the refrigerant to the storage compartment; A check valve disposed at an outlet side of the compressor to limit a refrigerant backflow to the compressor; And a backflow prevention device for preventing the refrigerant from flowing into the bypass flow passage from the oil separator.

According to the exemplary embodiment of the present invention, even when the cooling system is turned off and the operation of the compressor is stopped, the refrigerant on the compressor discharge side is restricted from being bypassed to the inlet side of the compressor. There is an advantage that can be prevented from occurring.

In addition, since the system high pressure and low pressure can be maintained within the set range when the system is OFF, there is an effect that the normal pressure range of the refrigerant system can be reached in the environment that can cool the storage compartment in a short time when the system restarts. In addition, since the time required for normal operation of the system can be reduced, the power consumption can be reduced.

In addition, since the backflow prevention part is provided on the discharge side of the compressor to prevent the refrigerant from being bypassed to the inlet side of the compressor, there is an advantage that the configuration of the system can be easily implemented.

In addition, since a valve device is provided in the bypass flow path for bypassing the discharge refrigerant of the compressor to the inlet side, the bypass flow of the refrigerant can be selectively limited, thereby effectively preventing oil separation through the oil separator and preventing pressure under the system pressure. The effect is that it can be done.

1 is a graph showing changes in high pressure and low pressure when the cooling system is OFF in the conventional cooling system.
2 is a system diagram showing the configuration of the air conditioning unit and the cooling unit according to the first embodiment of the present invention.
3 is a system diagram showing a configuration of an air conditioning unit and a cooling unit according to a second embodiment of the present invention.
4 is a system diagram showing a configuration of an air conditioning unit and a cooling unit according to a third embodiment of the present invention.
5 is a system diagram showing the configuration of the air conditioning unit and the cooling unit according to the fourth embodiment of the present invention.
Figure 6 is a graph showing the change in high pressure and low pressure when the cooling system OFF according to an embodiment of the present invention.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. It is to be understood, however, that the spirit of the invention is not limited to the embodiments shown and that those skilled in the art, upon reading and understanding the spirit of the invention, may easily suggest other embodiments within the scope of the same concept.

2 is a system diagram showing the configuration of the air conditioning unit and the cooling unit according to the first embodiment of the present invention.

Referring to FIG. 2, in a complex system according to an exemplary embodiment of the present invention, an air conditioning unit (or an air conditioning system) 1 and a heat exchanger with the air conditioning unit 1 which are operated for air conditioning of a setting space are cooled. Cooling section (or cooling system) 2 is included.

In detail, the air conditioning unit 1 includes an air conditioning compressor 10 for compressing an air conditioning refrigerant, a first heat exchanger 20 for condensing the refrigerant compressed by the air conditioning compressor 10, and the first air exchanger. A first expansion device 30 for depressurizing the refrigerant condensed in the heat exchanger 20 and a second heat exchanger 40 for evaporating the refrigerant passing through the first expansion device 30 are included. The air heat-exchanged in the first heat exchanger 20 or the second heat exchanger 40 may be supplied to the setting space for air conditioning.

In addition, the air conditioning unit 1 includes an air conditioning refrigerant pipe 50 for guiding the flow of the refrigerant circulating in the air conditioning unit. The refrigerant circulates through the air conditioning refrigerant pipe 50 and the air conditioning compressor 10, the first heat exchanger 20, the first expansion device 30, and the second heat exchanger 40.

The cooling unit 2 includes a cooling compressor 110 for compressing a cooling refrigerant, a second heat exchanger 40 for condensing the refrigerant compressed by the cooling compressor 110, and the second heat exchanger. The second expansion device 120 for reducing the refrigerant condensed in the 40, and at least a portion of the refrigerant provided to the inlet side of the second expansion device 120 and circulates the cooling unit to temporarily store the amount of circulating refrigerant Receiver 115 and an evaporator 130 for evaporating the refrigerant passing through the second expansion device 120. The cold air generated by the evaporator 130 may be supplied to the storage compartment. The storage compartment may be any one of a freezing compartment and a refrigerating compartment.

The second heat exchanger 40 may be referred to as a "cascade heat exchanger" as a configuration in which heat exchange is performed between the refrigerant circulating in the air conditioning unit 1 and the refrigerant circulating in the cooling unit 2. The refrigerant (first refrigerant) circulating in the air conditioning unit 1 and the refrigerant (second refrigerant) circulating in the cooling unit 2 flow into the second heat exchanger 40. In addition, the first refrigerant and the second refrigerant may be indirect heat exchange without mixing in the second heat exchanger 40.

The cooling unit 2 includes a cooling refrigerant tube 105 for guiding the flow of the refrigerant circulating through the cooling unit 2. The refrigerant circulates through the cooling refrigerant pipe 105 and the cooling compressor 110, the second heat exchanger 40, the second expansion device 120, and the evaporator 130.

The cooling unit 2 includes an oil separator 140 disposed at an outlet side of the cooling compressor 110 to separate oil contained in the high pressure refrigerant discharged from the cooling compressor 110. . Through the oil separator 140, the refrigerant from which the oil is separated is introduced into the second heat exchanger 40.

In addition, the oil separator 140 is connected with a bypass flow path 150 for allowing oil or refrigerant separated from the oil separator 140 to bypass the inlet side of the cooling compressor 110. That is, the bypass flow path 150 extends from the oil separator 140 to the inlet side of the cooling compressor 110.

The cooling refrigerant pipe 105 includes a lamination part 107 connected to the bypass flow path 150. The refrigerant flowing through the bypass flow path 150 from the oil separator 140 flows into the cooling refrigerant pipe 105 from the lamination part 107. In addition, the bypass flow path 150 includes a strainer 155 to remove impurities from oil or refrigerant separated from the oil separator 140.

The cooling unit 2 includes a first backflow prevention unit 160 to guide the one-way flow of the refrigerant. The cooling unit 2 may be provided at the outlet side of the oil separator 140 and the inlet side of the second heat exchanger 20. That is, the first backflow prevention unit 160 guides the flow from the oil separator 140 to the second heat exchanger 40 and restricts the flow in the opposite direction.

The first backflow prevention unit 160 may act to prevent the refrigerant from flowing into the bypass flow path 150 through the oil separator 140 when the operation of the cooling unit 2 is turned off. For example, the first backflow prevention unit 160 may include a check valve.

In addition, a second backflow prevention part 165 is provided between the cooling compressor 110 and the oil separator 140 to prevent a refrigerant backflow from the oil separator 140 to the cooling compressor 110. .

The operation of the cooling unit (cooling system) according to the present embodiment will be briefly described.

When the cooling system is turned on, the cooling compressor 110 is driven and the refrigerant is compressed to high pressure in the cooling compressor 110. The high pressure refrigerant flows into the oil separator 140 and separates oil from the oil separator 140. The separated oil or at least a portion of the refrigerant is bypassed to the inlet side of the cooling compressor 110 through the bypass flow path 150, and the refrigerant passes through the first backflow prevention part 160 to the second heat exchange. Flows into the unit 40.

On the other hand, when the cooling system is OFF, the driving of the cooling compressor 110 is stopped and the high pressure refrigerant contained in the outlet refrigerant pipe of the cooling compressor 110 among the cooling refrigerant pipes 105 is low pressure. There is a tendency to flow (backflow) to the inlet side of the formed cooling compressor 110. However, the backflow of the refrigerant may be limited by the first backflow prevention unit 160. That is, the flow of the refrigerant to the lamination part 107 through the bypass flow path 150 may be limited.

As a result, even when the cooling system is turned off, the high pressure refrigerant of the system may be mixed with the low pressure refrigerant to prevent the system pressure from being leveled. Thus, even if the cooling system is restarted, the time required to cool the storage compartment may be reduced. have.

In addition, by the second backflow prevention unit 165, the backflow of the refrigerant from the oil separator 140 to the cooling compressor 110 may be prevented.

Hereinafter, the second to fourth embodiments of the present invention will be described. Since these embodiments differ only in some configurations compared to the first embodiment and the previous embodiment, only the differences will be described, and the same reference numerals and descriptions of the first and previous embodiments are used.

3 is a system diagram showing a configuration of an air conditioning unit and a cooling unit according to a second embodiment of the present invention.

Referring to FIG. 3, the air conditioner 2 according to the second embodiment of the present invention includes an oil separator 140 disposed at an outlet side of a cooling compressor 110 to separate oil contained in a refrigerant, The bypass flow path 150 is provided to the bypass flow path 150 and the bypass flow path 150 to guide the oil or some refrigerant separated from the oil separator 140 to the inlet side of the cooling compressor 110. Included is a valve arrangement 170 that selectively restricts oil or refrigerant flow in the reactor. For example, the valve device 170 may include a solenoid valve.

The valve device 170, the control state is changed depending on whether or not the cooling unit (2). In detail, the valve unit 170 is opened when the cooling unit 2 is driven and the cooling compressor 110 is driven, and when the operation of the cooling unit 2 is stopped, the valve unit 170 is closed. Can be.

The valve device 170 and the backflow prevention part 160 of the first embodiment may be referred to as a "backflow prevention device" in terms of preventing the refrigerant backflow into the bypass flow path 150 when the cooling system is turned off. .

Hereinafter, the operation of the cooling system according to the present embodiment will be briefly described.

When the cooling system 2 is operated, the oil or some of the refrigerant contained in the refrigerant compressed by the cooling compressor 110 is separated from the oil separator 140 and the cooling compressor through the bypass passage 150. It is bypassed to the inlet side of 110. At this time, the valve device 170 is opened to guide the flow of oil or refrigerant through the bypass flow path 150.

On the other hand, when the cooling system 2 is turned off, the driving of the cooling compressor 110 is stopped, and the valve device 170 is closed. Accordingly, the outlet refrigerant of the cooling compressor 110 forming the high pressure may be prevented from flowing into the bypass flow path 150.

As a result, even when the cooling system 2 is OFF, the outlet high pressure region and the inlet low pressure region of the cooling compressor 110 can be separated, so that the system pressure can be prevented from being balanced.

4 is a system diagram showing a configuration of an air conditioning unit and a cooling unit according to a third embodiment of the present invention.

Referring to FIG. 4, in the cooling unit 2 according to the third embodiment of the present invention, oils for separating oil from refrigerants discharged from the plurality of compressors 210 and 220 and the compressors 210 and 220 compressing the refrigerant are provided. The separator 140 and a bypass flow path 150 for guiding oil or some refrigerant separated from the oil separator 140 to the inlet side of the plurality of compressors 210 and 220 are included.

The plurality of compressors 210 and 220 include a first compressor 210 and a second compressor 220 connected in parallel. For example, the first compressor 210 may be a constant speed compressor in which the operating frequency is kept constant, and the second compressor 220 may be an inverter compressor capable of adjusting the operating frequency. The refrigerant flowing through the cooling refrigerant pipe 105 may be branched into the plurality of compressors 210 and 220.

The cooling unit 2 is provided at the outlet side of the oil separator 140 and disposed at the outlet side of the condenser 280 and the condenser 280 for condensing the refrigerant compressed by the compressors 210 and 220. A second heat exchanger 40 for subcooling the refrigerant condensed in the condenser 280 is included. The second heat exchanger 40 functions as a "supercooler".

At the outlet side of the oil separator 140 and the inlet side of the condenser 280, a third backflow prevention part 260 for guiding the one-way flow of the refrigerant is included. By the third backflow prevention unit 260, the refrigerant may flow from the oil separator 140 to the condenser 280, the flow in the opposite direction is limited.

In addition, the cooling unit 2 includes a plurality of backflow prevention units 215 and 225 disposed at the outlet sides of the plurality of compressors 210 and 220 to guide the one-way flow of the refrigerant. The plurality of backflow prevention parts 215 and 225 may include a fourth backflow prevention part 215 disposed on an outlet side of the first compressor 210 and a fifth backflow prevention part disposed on an outlet side of the second compressor 220. Part 225 is included.

By the backflow prevention part 215, 225, the flow of the refrigerant from the oil separator 140 to the plurality of compressors 210, 220 may be limited.

The operation of the cooling unit (cooling system) according to the present embodiment will be briefly described.

When the cooling system is turned on, the plurality of compressors 210 and 220 are driven and the refrigerant is divided into the compressors 210 and 220 to be introduced and compressed at high pressure. The high pressure refrigerant flows into the oil separator 140 and separates oil from the oil separator 140. The separated oil or at least a portion of the refrigerant is bypassed to the inlet side of the cooling compressor 110 through the bypass flow path 150, and the refrigerant passes through the third backflow prevention part 260 to condense the condenser 280. Flows into).

On the other hand, when the cooling system is OFF, the operation of the compressor (210, 220) is stopped and the high-pressure refrigerant contained in the refrigerant pipe of the outlet side of the compressor (210, 220) of the cooling refrigerant pipe 105, the compressor 210 is formed low pressure Tends to flow (backflow) toward the inlet side. However, the backflow of the refrigerant may be limited by the third backflow prevention unit 160. That is, the flow of the refrigerant to the lamination part 107 through the bypass flow path 150 may be limited.

As a result, even when the cooling system is turned off, the high pressure refrigerant of the system may be mixed with the low pressure refrigerant to prevent the system pressure from being leveled. Thus, even if the cooling system is restarted, the time required to cool the storage compartment may be reduced. have.

In addition, the backflow of the refrigerant from the oil separator 140 to the compressors 210 and 220 may be prevented by the fourth and fifth backflow prevention units 215 and 225.

5 is a system diagram showing the configuration of the air conditioning unit and the cooling unit according to the fourth embodiment of the present invention.

Referring to FIG. 5, the air conditioner 2 according to the fourth embodiment of the present invention includes an oil separator 140 disposed at an outlet side of a plurality of compressors 210 and 220 to separate oil contained in a refrigerant, The bypass flow path 150 for guiding oil or some refrigerant separated from the oil separator 140 to the inlet side of the compressors 210 and 220 and the bypass flow path 150 are provided in the bypass flow path 150. Included is a valve arrangement 270 that selectively restricts oil or refrigerant flow. For example, the valve device 270 may include a solenoid valve.

The valve device 270 changes the control state depending on whether the cooling unit 2 is operated. In detail, when the cooling unit 2 is driven to drive the compressors 210 and 220, the valve device 270 is opened. When the cooling unit 2 is stopped, the valve device 270 may be closed. .

Hereinafter, the operation of the cooling system according to the present embodiment will be briefly described.

When the cooling system 2 is operated, the oil or a part of the refrigerant contained in the refrigerant compressed by the compressors 210 and 220 is separated from the oil separator 140 so that the compressors 210 and 220 of the compressor are passed through the bypass passage 150. Bypass to the inlet side. At this time, the valve device 270 is opened to guide the flow of the oil or refrigerant through the bypass flow path 150.

On the other hand, when the cooling system 2 is turned off, the driving of the cooling compressors 210 and 220 is stopped, and the valve device 270 is closed. Therefore, the outlet refrigerant of the compressors 210 and 220 forming the high pressure may be prevented from flowing into the bypass flow path 150.

As a result, even when the cooling system 2 is OFF, the outlet high pressure region and the inlet low pressure region of the cooling compressor 110 can be separated, so that the system pressure can be prevented from being balanced.

Figure 6 is a graph showing the change in high pressure and low pressure when the cooling system OFF according to an embodiment of the present invention.

Referring to Figure 6, the distribution of high pressure (compressor discharge pressure or condensation pressure) and low pressure (compressor suction pressure or evaporation pressure) that varies depending on whether the cooling system is operating.

The X-axis value refers to the time elapsed since the cooling system starts to operate, and the Y-axis value refers to the pressure value MPa regarding the change of the high pressure PH and the low pressure PL.

When the cooling system starts to operate at the time T0, the difference between the high pressure and the low pressure widens to reach the normal pressure range of the refrigerant system, and serves to supply cold air to the storage compartment. Here, the normal pressure range of the high pressure may be greater than or equal to P2 (MPa), and the normal pressure range of the low pressure may be less than or equal to P1 (MPa).

In this process, as shown in FIG. 6, when the operation of the cooling system is stopped at the time T1, the difference between the high pressure P _H2 and the low pressure P _L2 is drastically reduced in the conventional system, and the flat pressure ( High pressure and low pressure are formed at the same pressure) (T2). When the cooling system is operated again at T2, a difference between the high pressure P _H2 and the low pressure P _L2 is generated, and a pressure range of normal high pressure and low pressure is formed after a predetermined time elapses.

As such, according to the conventional system, when the operation of the cooling system is stopped, a flat pressure is generated between the high pressure and the low pressure, and it takes some time for the high pressure and the low pressure to form a normal pressure range again. As the operation rate rises, power consumption increases.

On the other hand, in the case of the system according to the embodiment of the present invention, even if the operation of the cooling system is stopped at time (T1), the range of the high pressure (P _H1 ) and low pressure (P _L1 ) is a large difference compared to when the system operating I never do that. Then, the high and low pressures when the cooling system is run again at T2 form a range similar to when the system is stopped. That is, the high pressure P _H1 may form a range of P1 or more and the low pressure P _L1 of P2 or less.

As described above, according to the system of the present invention, even when the operation of the cooling system is stopped or resumed, the high pressure and the low pressure can maintain the normal pressure range, so that the cooling of the storage compartment is faster and the power consumption is reduced as the system operation rate is improved. Appears.

1: air conditioning unit 2: cooling unit
10 air conditioning compressor 20 first heat exchanger
30: first expansion device 40: second heat exchanger
110: cooling compressor 120: second expansion device
130: evaporator 140: oil separator
150: bypass flow path 160: first backflow prevention unit
165: second backflow prevention unit 170: valve device
210: first compressor 215: fourth backflow prevention unit
220: second compressor 225: fifth backflow prevention unit
260: third backflow prevention unit 270: valve device
280: condenser

Claims (10)

A compressor for compressing the refrigerant;
A heat exchanger for condensing the refrigerant compressed by the compressor;
An oil separator provided at an inlet side of the heat exchanger and separating oil or some refrigerant from the high pressure refrigerant compressed by the compressor;
A bypass passage for bypassing the oil or refrigerant separated by the oil separator to an inlet side of the compressor; And
And a backflow preventing device provided at an outlet side of the oil separator or the bypass flow passage, and preventing a refrigerant from the outlet side of the compressor from flowing back into the bypass flow passage when the compressor is turned off. The method of claim 1,
The backflow prevention device,
And a first backflow prevention portion provided at an outlet side of the oil separator and restricting the flow of refrigerant from the oil separator to the bypass flow path. The method of claim 1,
The backflow prevention device,
And a valve device provided in the bypass flow path, the valve device selectively restricting flow of the refrigerant through the bypass flow path. The method of claim 3, wherein
Wherein the valve device comprises:
Cooling system, characterized in that open when the compressor is driven, closed when the compressor is OFF. The method of claim 1,
It is provided between the compressor and the oil separator,
And a second backflow prevention unit for preventing backflow of the refrigerant from the oil separator to the compressor when the compressor is turned off. The method of claim 1,
The heat exchanger
And a heat exchange between the refrigerant passing through the compressor and the refrigerant of the air conditioning unit including the air conditioning compressor. In the cooling system for performing heat exchange with the air conditioning unit is provided with an air conditioning compressor and cascade heat exchanger,
A compressor for compressing a cooling refrigerant;
An oil separator for separating oil from the refrigerant compressed by the compressor;
A bypass flow passage for bypassing the oil separated by the oil separator to an inlet side of the plurality of compressors;
A condenser for condensing the refrigerant passing through the oil separator;
An expansion device for depressurizing the refrigerant condensed in the condenser;
An evaporator for evaporating the refrigerant passing through the expansion device and supplying the refrigerant to the storage compartment;
A check valve disposed at an outlet side of the compressor to limit a refrigerant backflow to the compressor; And
And a backflow prevention device for preventing refrigerant from entering the bypass passage from the oil separator. The method of claim 7, wherein
The backflow prevention device,
And a backflow prevention portion disposed between the oil separator and the condenser and a valve device provided in the bypass flow path and selectively opened. The method of claim 7, wherein
When the cooling system is operated, the refrigerant flowing in the bypass flow passage passes through the valve device,
And when the operation of the cooling system is stopped, the valve device cuts off the refrigerant in the bypass flow path. The method of claim 7, wherein
The compressor is provided in plurality,
And said check valve is provided at each outlet side of said plurality of compressors.

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