KR101319778B1 - Air conditioner - Google Patents

Abstract

The present invention relates to an air conditioner. Air conditioner according to one aspect, at least one indoor unit; And at least one outdoor unit connected to the at least one indoor unit, wherein the at least one outdoor unit includes a compressor, an outdoor heat exchanger, a subcooling unit for subcooling a refrigerant, and a unit for communicating the subcooling unit with a suction side of the compressor. A first refrigerant pipe, a first valve provided in the first refrigerant pipe, a second refrigerant pipe connecting the intermediate pressure stage of the compressor and the first refrigerant pipe, and a second valve provided in the second refrigerant pipe. In the first refrigerant flow mode, the refrigerant flowing through the subcooling unit flows into the compressor through the second refrigerant pipe, and in the second refrigerant flow mode, the refrigerant compressed by the compressor is the second refrigerant pipe It is characterized in that the discharge.

Description

Air Conditioner

This specification relates to an air conditioner.

Background Art [0002] Generally, an air conditioner is a device for cooling and heating indoor air or purifying air using a refrigerant cycle including a compressor, a condenser, an expansion device, and an evaporator to create a more comfortable indoor environment for a user.

The air conditioner includes an air conditioner in which one indoor unit is connected to one outdoor unit, and a multi-type air conditioner which achieves the same effect as installing a plurality of air conditioners by connecting a plurality of indoor units to one or more outdoor units.

The at least one outdoor unit includes a compressor, an outdoor heat exchanger, an outdoor expansion device, and a subcooler. Also, when the difference between the high pressure and the low pressure of the compressor is large, the outdoor unit injects the supercooled refrigerant into the compressor to reduce the pressure difference.

The outdoor unit may include, for example, a bypass pipe for bypassing the refrigerant discharged from the compressor to a suction side when the high pressure of the compressor increases when the load of the refrigerant cycle is large, and a bypass valve provided in the bypass pipe. do.

According to the conventional air conditioner as described above, there is a problem in that the structure is complicated and the cost increases as the pipes for the refrigerant injection and the pipes for the refrigerant bypass are respectively present.

An object of the present invention is to provide an air conditioner capable of injecting a refrigerant and bypassing a high pressure refrigerant by using a single pipe.

According to an aspect, an air conditioner includes: at least one indoor unit; And at least one outdoor unit connected to the at least one indoor unit, wherein the at least one outdoor unit includes a compressor, an outdoor heat exchanger through which the refrigerant compressed by the compressor flows, an outdoor expansion device connected to the outdoor heat exchanger, and the outdoor unit The refrigerant is supercooled by heat-exchanging a liquid pipe connected to an expansion mechanism, a bypass pipe for bypassing the refrigerant in the liquid pipe, and a refrigerant connected to the bypass pipe and flowing through the refrigerant flowing in the liquid pipe and the bypass pipe. To connect the subcooling unit, a first refrigerant pipe for communicating the subcooling unit with the suction side of the compressor, a first valve provided in the first refrigerant pipe, a medium pressure end of the compressor, and the first refrigerant pipe. The second refrigerant pipe and the second valve provided in the second refrigerant pipe, the air conditioner in the cooling mode If the operating condition of the injection mode is satisfied during the operation, it is operated in the injection mode, and if the operating condition of the refrigerant bypass mode is satisfied while the air conditioner is operating in the cooling mode, the operation is performed in the refrigerant bypass mode. The refrigerant supercooled by the subcooling unit flows into the compressor through the second refrigerant pipe. In the refrigerant bypass mode, the refrigerant compressed in the compressor is discharged into the second refrigerant pipe, and the first refrigerant is supplied. After flowing to the pipe is characterized in that the flow to the suction side of the compressor.

According to the proposed invention, since the supercooled refrigerant can be introduced into the evaporator, the amount of heat absorbed from the heat exchanger is further increased and the cooling performance of the overall air conditioner is improved.

In addition, since the medium pressure refrigerant may be injected into the compressor, the differential pressure between the high pressure and the low pressure of the compressor is reduced, and the flow rate of the refrigerant discharged from the compressor to the condenser is increased, thereby improving cycle performance. .

In addition, since the path for refrigerant injection and the path through which the medium pressure compressor refrigerant is discharged are common paths, there is no need for an additional piping for refrigerant bypass, so the refrigerant cycle structure is simple and manufacturing costs are reduced.

In addition, since the medium pressure refrigerant is bypassed in the compressor, the flow rate is bypassed as compared with the case where the high pressure is bypassed, so that a separate capillary is unnecessary.

1 is a refrigerant cycle diagram of an air conditioner according to an embodiment of the present invention.
2 is a view showing a refrigerant flow when the air conditioner according to an embodiment of the present invention operates in the normal mode.
3 is a view showing a refrigerant flow when the air conditioner according to an embodiment of the present invention operates in the injection mode.
4 is a view showing a refrigerant flow when the air conditioner according to an embodiment of the present invention operates in the refrigerant bypass mode.

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

1 is a refrigerant cycle diagram of an air conditioner according to an embodiment of the present invention.

Referring to FIG. 1, an air conditioner according to an embodiment of the present disclosure may include an outdoor unit 10 and an indoor unit 20 connected to the outdoor unit 10 by a refrigerant pipe.

The indoor unit 20 includes a plurality of indoor units 21 and 22. In the present specification, for convenience of description, one outdoor unit is described as an example of being connected to two indoor units, but in the present specification, the number of indoor units and the number of outdoor units are not limited. That is, two or more indoor units may be connected to two or more outdoor units, or one indoor unit may be connected to one outdoor unit.

The outdoor unit 10 includes a compression unit 110 for compressing a refrigerant, and an outdoor heat exchanger 130 for exchanging outdoor air with the refrigerant.

The compression unit 110 may include one or more compressors. In this embodiment, as an example, the compression unit 110 will be described that includes a plurality of compressors (111, 112). Some of the compressors 111, 112 and 113 are inverter compressors 111 whose capacity is variable and others may be constant speed compressors 112 and 113. Alternatively, all of the plurality of compressors 111 and 112 may be constant speed compressors or inverter compressors. The plurality of compressors 111 and 112 may be arranged in parallel. Depending on the capacity of the indoor unit 1, some or all of the plurality of compressors may operate.

The discharge side piping of each of the compressors 111 and 112 includes an individual piping 115 and a lamination piping 116. That is, the individual pipes 115 of the compressors 111 and 112 are laminated in the lamination pipes 116. Each of the individual pipes 115 may be provided with oil separators 113 and 114 for separating oil from the refrigerant. The oil separated in the oil separators 113 and 114 may be recovered by the accumulator 135 or by the respective compressors 111 and 112.

The lamination pipe 116 is connected to the four-way valve 120 for switching the flow path of the refrigerant. The four-way valve 120 is connected to the outdoor heat exchanger 130 by a connection pipe 122. The four-way valve 120 may be connected to the accumulator 135, and the accumulator 135 may be connected to the compression unit 110.

The outdoor heat exchanger 130 includes a first outdoor heat exchanger 131 (hereinafter referred to as a "first heat exchanger") and a second outdoor heat exchanger 132 (hereinafter referred to as a "second heat exchanger"). do. Each of the first heat exchanger 131 and the second heat exchanger 132 may be a separate independent heat exchanger or a heat exchanger classified based on the flow of the refrigerant in a single outdoor heat exchanger. The first heat exchanger 131 and the second heat exchanger 132 may be disposed in the horizontal direction or in the vertical direction. In addition, the heat exchange capacity of the first heat exchanger 131 and the second heat exchanger 132 may be the same or different.

The refrigerant of the outdoor heat exchanger 130 may exchange heat with outdoor air blown by the outdoor fan motor assembly 137 (including an outdoor fan and a fan motor). One or more outdoor fan motor assemblies may be provided. In FIG. 1, for example, one outdoor fan motor assembly is provided.

The outdoor unit 10 further includes an outdoor expansion mechanism 140. The outdoor expansion mechanism 140 does not expand the refrigerant when the refrigerant passing through the outdoor heat exchanger 130 passes, and expands the refrigerant when the refrigerant not passing through the outdoor heat exchanger 130 passes.

The outdoor expansion mechanism 140 includes a first outdoor expansion valve 141 connected to the first heat exchange part 131, and a second outdoor expansion valve 142 connected to the second heat exchange part 132. do. The first check valve 143 is disposed in parallel with the first outdoor expansion valve 141, and the second check valve 144 is disposed in parallel with the second outdoor expansion valve 142.

The refrigerant expanded by the first outdoor expansion valve 141 may flow to the first heat exchange unit 131, and the refrigerant expanded by the second outdoor expansion valve 142 may include the second heat exchange unit ( 132). Each of the outdoor expansion valves 141 and 142 may be, for example, an electromagnetic expansion valve (EEV).

On the other hand, the bypass pipe unit 116 is connected to the bypass piping unit. The bypass piping unit is connected to pipes connecting the heat exchange parts 131 and 132 to the outdoor expansion valves 141 and 142. The bypass piping unit may include a common pipe 150, a first bypass pipe 151 and a second bypass pipe 152 branched from the common pipe 150. The first bypass pipe 151 is connected to a pipe connecting the first heat exchange part 131 and the first outdoor expansion valve 141, and the second bypass pipe 152 is connected to the second heat exchange. It is connected to the pipe connecting the portion 132 and the second outdoor expansion valve 142.

In addition, a first bypass valve 153 is provided in the first bypass pipe 151, and a second bypass valve 154 is provided in the second bypass pipe 152. Each of the bypass valves 153 and 154 may be, for example, a solenoid valve capable of adjusting the flow rate. As another example, the common piping may be omitted from the bypass piping unit, and the first piping and the second bypass piping may be included.

The bypass valves 153 and 154 may be opened during a heating operation. When the bypass valves 153 and 154 are opened, the bypass pipes 151 and 152 may be connected to the compression unit 110. The compressed hot refrigerant can flow. When the high temperature refrigerant flows through the bypass pipes 151 and 152, the outdoor heat exchanger 130 may be defrosted by the high temperature refrigerant.

The outdoor expansion mechanism 140 may be connected to the subcooler 160 by a liquid pipe 34. The liquid pipe 34 is connected with a bypass pipe 162 for bypassing the refrigerant passing through the subcooler to the subcooler 160. Since the structure and the pipe connection relationship of the subcooler 160 may be implemented by a known structure, a detailed description thereof will be omitted. The bypass pipe 162 is provided with a subcooling valve 164 to adjust the flow rate of the refrigerant and to expand the refrigerant. The subcooling valve 164 adjusts the flow rate of the refrigerant flowing to the first refrigerant pipe 170 to be described later.

In the present embodiment, since the subcooler 160, the bypass pipe 162, and the subcooling valve 164 are configured to supercool the refrigerant, the subcooler 160 may be referred to collectively as a subcooling unit.

The subcooler 160 communicates with the bypass pipe 162 and is connected to a first refrigerant pipe 170 connected to the accumulator 135. For example, the first refrigerant pipe may be connected to a pipe 121 connecting the four-way valve 120 and the accumulator 135. In addition, the first refrigerant pipe 170 is provided with a first valve 172. The first valve 172 may be, for example, a solenoid valve. In the present embodiment, the first refrigerant pipe 170 has been described as being connected to the accumulator 135. Alternatively, the first refrigerant pipe 170 is connected to the inlet pipe of the accumulator 135 or the inlet pipe of the compression unit. It is also possible. That is, in the present invention, the first refrigerant pipe 170 serves to communicate the subcooling unit with the suction side of the compression unit.

A second refrigerant pipe is connected to the first refrigerant pipe 170. The second refrigerant pipe includes a common pipe 180, a first branch pipe 182 and a second branch pipe 184 branched from the common pipe 180. The first branch pipe 182 is connected to the first compressor 111, and the second branch pipe 184 is connected to the second compressor 112. In the present embodiment, each of the compressors 111 and 112 is a compressor capable of multistage compression, and may include a plurality of compression chambers.

Each of the branch pipes 182 and 184 may communicate with a specific compression chamber (compression chamber into which a refrigerant compressed one or more times is introduced) of the plurality of compression chambers. For example, if the compressor includes two compression chambers (compresses the refrigerant compressed in the first compression chamber in the second compression chamber), it can communicate with the second compression chamber, and includes three or more compression chambers. May be in communication with either the second compression chamber or the next compression chamber. That is, the suction side of the compressor is a low pressure region, the discharge side of the compressor is a high pressure region, and the region to which the branch pipes 183 and 185 are connected is a medium pressure region.

The first branch pipe 182 is provided with a first branch valve 183, and the second branch pipe 184 is provided with a second branch valve 185. Each of the branch valves 183 and 185 may be, for example, a solenoid valve. The first branch valve 183 and the second branch valve 185 may be referred to as a second valve in a relationship with the first valve 172.

As another example, the branch pipe may not be provided with a valve, and the common pipe may be provided with a valve.

The outdoor unit 10 may be connected to the indoor unit 20 by an engine 31 and a liquid pipe 34. The engine 31 may be connected to the four-way valve 120, the liquid pipe 34 may be connected to the outdoor expansion mechanism (140). That is, in this embodiment, the pipes connected to both sides of the subcooler may be referred to as a liquid pipe 34.

The indoor units 21 and 22 may include indoor heat exchangers 211 and 221, indoor fans 212 and 222, and indoor expansion mechanisms 213 and 223. The indoor expansion mechanisms 213 and 223 may be, for example, electromagnetic expansion valves (EEVs).

Hereinafter, the refrigerant flow in the air conditioner according to the embodiment of the present invention will be described.

The operation mode of the air conditioner according to the present embodiment includes a normal mode (normal cooling mode or general heating mode or a third refrigerant flow mode), an injection mode (or a first refrigerant flow mode), and a refrigerant bypass mode (second refrigerant). Flow mode). The above modes may be classified according to the flow direction of the refrigerant.

2 is a view showing a refrigerant flow when the air conditioner according to an embodiment of the present invention operates in the normal mode. In FIG. 2, for example, the refrigerant flow when the air conditioner operates in the cooling mode is shown.

Referring to FIG. 2, when the air conditioner operates in a general cooling mode, the high temperature and high pressure refrigerant discharged from the compression unit 110 of the outdoor unit 10 may be supplied to the outdoor heat exchanger by controlling the flow path of the four-way valve 120. Flow to the side 130.

The refrigerant flowing toward the outdoor heat exchanger 130 is condensed while flowing through the heat exchange parts 131 and 132. At this time, in the normal refrigerant mode of the air conditioner, the bypass valves 153 and 154 and the outdoor expansion valves 141 and 142 are closed.

Therefore, the refrigerant discharged from the compression unit 110 may not pass through the bypass pipes 151 and 152. The refrigerant discharged from the heat exchange parts 131 and 132 passes through the check valves 143 and 144.

The condensation refrigerant then flows to the subcooler 160. Some of the refrigerant passing through the subcooler 160 is expanded by the subcooling valve 164 while flowing through the bypass pipe 162. In addition, the refrigerant expanded by the subcooling valve 164 enters the subcooler 160 and exchanges heat with the condensation refrigerant flowing along the liquid pipe 34.

According to the present embodiment, the refrigerant flowing along the bypass pipe 162 passes through the subcooling valve 164 and the temperature and the pressure decrease. Therefore, the temperature of the refrigerant passing through the subcooling valve 164 is relatively lower than the temperature of the refrigerant flowing through the liquid pipe 34. Therefore, the condensed refrigerant is supercooled in the course of passing through the subcooler 160. As the condensed refrigerant is supercooled, the low-temperature refrigerant may be introduced into the indoor heat exchanger, thereby increasing the amount of heat absorbed from the indoor air and improving the cooling performance of the overall air conditioner.

At this time, even when the air conditioner operates in the normal heating mode, the refrigerant may be supercooled, and the supercooled refrigerant flows into the outdoor heat exchanger. Therefore, the heating performance of the air conditioner can be improved.

The refrigerant of the bypass pipe 162 flows through the subcooler 160 to the first refrigerant pipe 170. At this time, in the normal cooling mode of the air conditioner, the first valve 172 is opened, and each of the branch valves 183 and 185 is closed (the same is true in the normal heating mode). Accordingly, the refrigerant introduced into the bypass pipe 162 is introduced into the accumulator 135 without being bypassed to the compressors 111 and 112.

On the other hand, the refrigerant flowing through the liquid pipe 34 is introduced into the respective indoor units (21, 22). The refrigerant introduced into the indoor units 21 and 22 is expanded by the indoor expansion mechanisms 213 and 223 and then introduced into the indoor heat exchangers 211 and 221. The refrigerant is evaporated while flowing through each of the indoor heat exchangers 211 and 221 and then moved to the outdoor unit 10 along the engine 31. The refrigerant then flows through the four-way valve 120 to the accumulator 135. A gaseous refrigerant is introduced into the compression unit 110 among the refrigerant introduced into the accumulator 135.

3 is a view showing a refrigerant flow when the air conditioner according to an embodiment of the present invention operates in the injection mode. In FIG. 3, for example, the refrigerant flow when the air conditioner is switched to the injection mode while operating in the cooling mode is shown.

Referring to FIG. 3, the injection mode of the air conditioner in the present embodiment is basically the same as the general cooling mode, except that there are differences in the states of the first valve 172 and the branch valves 183 and 185. Therefore, hereinafter, only portions that differ from the general cooling mode of the air conditioner will be described.

When the differential pressure between the high pressure and the low pressure of the compression unit 110 becomes higher than the reference pressure while the air conditioner is operating in the normal cooling mode (high pressure is high or low pressure is low) (operation condition of the injection mode is satisfied) The first valve 172 is closed, and each of the branch valves 183 and 185 is opened. As another example, when the compression ratio (ratio of high pressure to low pressure) is greater than or equal to the reference compression ratio (when the operating condition of the injection mode is satisfied), the first valve 172 is closed and each of the branch valves 183 and 185. Is opened.

Then, the refrigerant discharged from the subcooler 160 to the first refrigerant pipe 170 is injected into the compressors 111 and 112 along the common pipe 180 and the branch pipes 182 and 184. do. At this time, the pressure of the refrigerant injected into the compressors 111 and 112 is an intermediate pressure between the discharge side pressure of the compressor and the suction side pressure of the compressor.

According to this embodiment, since the medium pressure refrigerant is injected into each of the compressors 111 and 112, the differential pressure between the high pressure and the low pressure of the compressors 111 and 112 is reduced, and the discharge from the compressors 111 and 112 is performed. Therefore, the flow rate of the refrigerant flowing to the condenser (outdoor heat exchanger for cooling or indoor heat exchanger for heating) is increased, thereby improving cycle performance.

While the air conditioner is operating in the injection mode, the branch valves 183 and 185 are closed and the first valve 172 is opened when the differential pressure between the high pressure and the low pressure is lower than the reference pressure, so that the air conditioner is in the normal mode. Will work. As another example, while the air conditioner is operating in the injection mode, when the compression ratio (ratio of high pressure to low pressure) becomes less than the reference compression ratio, the branch valves 183 and 185 are closed and the first valve 172 is closed. The air conditioner is opened to operate in the normal mode.

4 is a view showing a refrigerant flow when the air conditioner according to an embodiment of the present invention operates in the refrigerant bypass mode. In FIG. 4, for example, the refrigerant flow when the air conditioner is switched to the refrigerant bypass mode while operating in the cooling mode is illustrated.

Referring to FIG. 4, in the present embodiment, the cooling and bypassing mode of the air conditioner is basically the same as the general cooling mode, except that there are differences in the states of the branch valves 183 and 185 and the subcooling valve 164. . Therefore, hereinafter, only portions that differ from the general cooling mode of the air conditioner will be described.

When the cycle load increases while the air conditioner is operating in the normal cooling mode (for example, when the high pressure of the compression unit exceeds the reference pressure) (when the operating condition of the refrigerant bypass mode is satisfied), the subcooling valve 164 is closed and each of the branch valves 183 and 185 is opened.

Then, the medium pressure refrigerant compressed in some compression chambers among the plurality of compression chambers of each of the compressors 111 and 112 is bypassed to the branch pipes 182 and 184. In addition, the refrigerant bypassed to the branch pipes 182 and 184 flows into the first refrigerant pipe 170 through the common pipe 180. Then, the refrigerant flows into the accumulator 135 after passing through the first refrigerant pipe 170.

According to the present embodiment, since the medium pressure inside the compressors 111 and 112 is discharged from the compressors 111 and 112 and flows to the accumulator, the flow rate of the compressors 111 and 112 is reduced, and the compressor The high pressure of H can be lowered and the cycle load can be reduced.

In addition, according to the present embodiment, since the branch pipe serves to discharge not only the path for the refrigerant injection but also the medium pressure compressor refrigerant, since a pipe for the separate refrigerant bypass is unnecessary, the refrigerant cycle structure is simple and the manufacturing cost This has the advantage of shrinking.

In addition, since the medium pressure refrigerant is bypassed in the compressors 111 and 112, the flow rate that is bypassed is small compared to the case where the high pressure is bypassed, so that a separate capillary is unnecessary.

On the other hand, when the cycle load becomes small while the air conditioner is operating in the refrigerant bypass mode (when the high pressure of the compression unit becomes lower than the reference pressure, the branch valves 183 and 185 are closed, and the subcooling valve 164 is closed. Is opened, causing the air conditioner to operate in normal mode.

In the above embodiment has been described when the air conditioner is operated in the normal cooling mode, the idea of the present invention can be equally applied even when the air conditioner is operated in the normal heating mode. That is, it may be switched to the injection mode or the refrigerant bypass mode while operating in the normal heating mode.

10: outdoor unit 21, 22: indoor unit
160: supercooler 170: first refrigerant piping
180: common pipe 182: first branch pipe
184: second branch pipe

Claims (8)

At least one indoor unit; And
At least one outdoor unit connected to the at least one indoor unit,
The at least one outdoor unit,
With compressor,
An outdoor heat exchanger into which the refrigerant compressed by the compressor is introduced;
An outdoor expansion device connected to the outdoor heat exchanger;
A liquid pipe connected to the outdoor expansion mechanism;
Bypass piping for bypassing the refrigerant in the liquid pipe,
A subcooling unit connected to the bypass pipe and configured to supercool the refrigerant by heat-exchanging a refrigerant of the liquid pipe and a refrigerant flowing through the bypass pipe;
A first refrigerant pipe for communicating the subcooling unit with the suction side of the compressor;
A first valve provided in the first refrigerant pipe,
A second refrigerant pipe connecting the medium pressure end of the compressor and the first refrigerant pipe;
It includes a second valve provided in the second refrigerant pipe,
If the operating condition of the injection mode is satisfied while the air conditioner is operating in the cooling mode, it operates in the injection mode,
If the operating condition of the refrigerant bypass mode is satisfied while the air conditioner is operating in the cooling mode, it operates in the refrigerant bypass mode,
In the injection mode, the refrigerant supercooled by the subcooling unit flows into the compressor through the second refrigerant pipe,
In the refrigerant bypass mode, the refrigerant compressed by the compressor is discharged into the second refrigerant pipe, and flows to the suction side of the compressor after flowing into the first refrigerant pipe. The method of claim 1,
In the cooling mode, the refrigerant flowing through the subcooling unit flows through the first refrigerant pipe to the suction side of the compressor. 3. The method of claim 2,
The injection mode is performed when the differential pressure between the high pressure and the low pressure of the compressor is equal to or greater than the reference pressure, or the compression ratio of the high pressure to the low pressure becomes equal to or greater than the reference compression ratio. The method of claim 3, wherein
In the injection mode, the first valve is closed and the second valve is open. 3. The method of claim 2,
The refrigerant bypass mode is performed when the high pressure of the compressor exceeds a reference pressure. The method of claim 5, wherein
The bypass pipe is provided with a subcooling valve for adjusting the flow rate of the refrigerant flowing into the first refrigerant pipe,
In the refrigerant bypass mode, the subcooling valve is closed, and the first valve and the second valve are open. The method according to claim 6,
In the cooling mode, the subcooling valve and the first valve is opened, the second valve is closed. The method of claim 1,
The compressor includes a plurality of compression chambers for multi-stage compression,
The second refrigerant pipe is an air conditioner in communication with the compression chamber is introduced into the refrigerant compressed one or more times of the plurality of compression chambers.

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