WO2016110974A1 - Air conditioner - Google Patents

Abstract

Provided is an air conditioner that is capable of storing a surplus refrigerant while coping with a change in the installation environment. The air conditioner (200) is provided with a refrigerating cycle circuit (100) in which a compressor (1), an outdoor heat exchanger (3), a depressurizing device (6), an indoor heat exchanger (7), and a refrigerant storing unit (5) are connected to each other via refrigerant piping, and is capable of switching between a heating operation and a cooling operation. A switching means is included which switches the position of the refrigerant storing unit (5) between a location between the outdoor heat exchanger (3) and the depressurizing device (6) and a location between the indoor heat exchanger (7) and the depressurizing device (6).

Description

Air conditioner

The present invention relates to an air conditioner, and particularly relates to the processing of surplus refrigerant.

Generally, an air conditioner in which a compressor, an indoor heat exchanger, a pressure reducing device, and an outdoor heat exchanger are connected in order through a refrigerant pipe to enable switching between air conditioning and heating is known. In this type of air conditioner, the internal volume of the refrigerant pipe of the outdoor heat exchanger is generally larger than that of the indoor heat exchanger. At the time of cooling operation using the outdoor heat exchanger as a condenser, a refrigerant charging amount is required so that the liquid refrigerant pipe from the outdoor heat exchanger to the pressure reducing device is filled with the liquid refrigerant. Further, during heating operation, a refrigerant filling amount is required so that the liquid refrigerant pipe from the indoor heat exchanger to the decompression device is filled with the liquid refrigerant, but the indoor heat exchanger with a relatively small internal volume is a condenser. Therefore, the amount of liquid refrigerant is smaller than that during cooling operation. Thus, there is a difference between the required refrigerant charge amount during the cooling operation and the heating operation.

When the required refrigerant charge amount is larger during the cooling operation, a difference amount of the refrigerant obtained by subtracting the required refrigerant charge amount during the heating operation from the required refrigerant charge amount during the cooling operation is generated as a surplus refrigerant during the heating operation. In general, an air conditioner uses a receiver tank or an accumulator to store excess refrigerant. When surplus refrigerant is generated during the heating operation, it is installed between the indoor heat exchanger that functions as a condenser and the decompression device, and stores the surplus refrigerant.
For example, Patent Literature 1 discloses an air conditioner that uses a part of an outdoor heat exchanger as a storage unit and enables storage of excess refrigerant without providing a receiver tank.
Patent Document 2 discloses an air conditioner that includes a receiver tank on the indoor unit side, stores liquid refrigerant during heating operation, and stores excess refrigerant generated during heating operation.

Japanese Patent Laid-Open No. 10-238895 (page 4, FIG. 1) Japanese Patent Laying-Open No. 2005-214501 (page 13, FIG. 1)

An air conditioner is installed in a room whose temperature is to be controlled, and includes an indoor unit on which an indoor heat exchanger or the like is mounted, and an outdoor unit that is installed outside and on which an outdoor heat exchanger or the like is mounted. The outdoor unit and the indoor unit are connected by a connection pipe so that the refrigerant can come and go. The length of the connection pipe varies depending on the conditions for installing the air conditioner.
When the connection pipe connecting the outdoor unit and the indoor unit is short, the internal volume of the outdoor heat exchanger pipe is generally larger than that of the indoor heat exchanger. Will be more. However, the refrigerant in the connection pipe connecting the indoor unit and the outdoor unit becomes a gas-liquid two-phase refrigerant by an expansion valve installed in the outdoor unit during the cooling operation, and an indoor heat exchanger that becomes a condenser during the heating operation It becomes a liquid refrigerant. In other words, when the connection pipe connecting the indoor unit and the outdoor unit is long, the amount of liquid refrigerant that fills the connection pipe during heating operation is required, and the required refrigerant charging amount may be larger during heating operation. is there. In other words, depending on the condition in which the air conditioner is installed, the required refrigerant charging amount during the heating operation may be larger than during the cooling operation.

In the technique disclosed in Patent Document 1, a receiver tank is not provided and a part of the outdoor heat exchanger is used as a storage unit, and the storage unit is disposed before or after the decompression device to store excess refrigerant. Or it was necessary to be limited to the conditions which generate | occur | produce a surplus refrigerant | coolant only in either one at the time of heating operation.
Further, in the technique disclosed in Patent Document 2, the receiver tank is provided on the downstream side of the indoor heat exchanger during heating operation, and can store excess refrigerant during heating. It is necessary to be limited to a condition in which surplus refrigerant is generated only in one of the heating operations. Also, depending on the difference in the internal volume between the outdoor heat exchanger and the indoor heat exchanger and the length of the connecting pipe connecting the indoor unit and the outdoor unit, the excess refrigerant to be stored increases, and it is necessary to enlarge the receiver tank. It was.

The present invention has been made to solve the above problems, and even if the length of the connecting pipe changes depending on the installation condition of the air conditioner, and the appropriate refrigerant amount during the cooling operation and the heating operation changes. An object of the present invention is to provide an air conditioner capable of storing excess refrigerant.

An air conditioner according to the present invention includes a refrigeration cycle circuit in which a compressor, an outdoor heat exchanger, a decompression device, an indoor heat exchanger, and a refrigerant reservoir are connected by refrigerant piping, and heating operation and cooling In the air conditioner capable of switching between operation, the refrigerant storage unit is arranged between the outdoor heat exchanger and the pressure reducing device and between the indoor heat exchanger and the pressure reducing device. It has switching means for switching.

In the air conditioner of the present invention, the refrigerant storage unit and the decompression device are connected in series, and the order of the refrigerant storage unit and the decompression device can be switched back and forth on the refrigeration cycle circuit. By making it possible to change the refrigerant storage part for storing excess refrigerant before and after the decompression device, it is possible to store excess refrigerant during both heating and cooling operations. Therefore, even if the length of the connecting pipe connecting the outdoor unit and the indoor unit changes, installation is possible.

1 is a diagram of a refrigeration cycle circuit of an air conditioner according to Embodiment 1. FIG. It is the schematic which shows the required refrigerant | coolant amount by the difference in length of the connection piping of an air conditioner. It is a figure of the refrigerating cycle circuit at the time of the short length of the air conditioner of FIG. It is a figure of the refrigerating cycle circuit at the time of the elongate of the air conditioner of FIG. It is a figure of the refrigerating cycle circuit of the air conditioner which concerns on Embodiment 2. FIG.

Embodiment 1 FIG.
FIG. 1 is a diagram of a refrigeration cycle circuit 100 of an air conditioner 200 according to Embodiment 1 of the present invention.
As shown in FIG. 1, the air conditioner 200 includes a refrigeration cycle circuit 100 and a control device 40. The refrigeration cycle circuit 100 includes a compressor 1 that compresses and discharges a refrigerant, a four-way valve 2 that switches a connection destination of a discharge port and a suction port of the compressor, an outdoor heat exchanger 3, a decompression device 6, and indoor heat. The exchanger 7, the refrigerant | coolant storage part 5, and the switching valve 4 are connected by refrigerant | coolant piping. The air conditioner 200 can be operated by switching between a cooling operation and a heating operation. Switching between the cooling operation and the heating operation is performed by switching the connection destination of the discharge port and the suction port of the compressor 1 by the four-way valve 2. In FIG. 1, the four-way valve 2 can switch the path to a solid line or a broken line. In the state where the four-way valve 2 in FIG. 1 is indicated by a solid line, the air conditioner 200 performs a cooling operation, and in the state indicated by a broken line, the air conditioner 200 performs a heating operation. The four-way valve 2 may have another structure as long as the connection destinations of the discharge port and the suction port of the compressor 1 can be switched.

The outdoor unit 30 and the indoor unit 70 are each an integral unit. The outdoor unit 30 includes the compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the decompression device 6, the refrigerant reservoir 5, and the switching valve 4. And the indoor heat exchanger 7 is mounted on the indoor unit 70.
A connection pipe 50 and a connection pipe 51 are installed between the outdoor unit 30 and the indoor unit 70 so that the refrigerant can come and go. The connection pipe 50 and the connection pipe 51 are installed with their lengths changed depending on the conditions under which the air conditioner 200 is installed.

In the refrigeration cycle circuit 100, the refrigerant reservoir 5 and the decompression device 6 are connected in series, and are disposed between the outdoor heat exchanger 3 and the indoor heat exchanger 7. The switching valve 4 is connected to both ends of the refrigerant reservoir 5 and the decompression device 6 connected in series, and when one of the ends is connected to the outdoor heat exchanger 3, the other is the indoor heat exchanger 7. The connection destinations can be switched in the reverse direction. In FIG. 1, the switching valve 4 can switch a path | route to the state of a continuous line or a broken line.
The switching valve 4 can be configured to manually switch the path when the air conditioner 200 is installed, or the path is routed by an instruction given from the control device 40 according to an instruction input to a setting device (not shown). It is also possible to take a configuration for switching.

Further, the switching valve 4 may be constituted by a four-way valve. With the four-way valve, it is possible to replace the two outflow paths, which are the connection destinations of the refrigerant flowing in from the two-path piping. When a four-way valve is used in the refrigeration cycle circuit 100, piping from each of the outdoor heat exchanger 3, the indoor heat exchanger 7, the refrigerant storage unit 5, and the decompression device 6 is connected to the four-way valve used as the switching valve 4. Is done. For example, when the state of the four-way valve used as the switching valve 4 is such that the indoor heat exchanger 7 and the refrigerant reservoir 5 are connected, and the outdoor heat exchanger 3 and the pressure reducing device 6 are connected, From this state, the indoor heat exchanger 7 and the decompression device 6 can be connected, and the outdoor heat exchanger 3 and the refrigerant reservoir 5 can be switched to a connected state. The four-way valve used as the switching valve 4 switches the connection in the refrigeration cycle circuit 100 by switching the path by an electromagnetic method, for example.

The control device 40 is a pressure sensor (not shown) for detecting each pressure of the high pressure side pressure and the low pressure side pressure of the compressor 1 as a result of detection by a temperature sensor (not shown) for detecting the temperature of each part of the compressor 1 and the like. ), The operation of the compressor 1, the operation of the fans (not shown) attached to the outdoor unit 30 and the indoor unit 70 based on the output from the setting device (not shown) operated by the user, etc. The switching of the route of the four-way valve 2 and the switching of the route of the switching valve 4 are controlled. The control device 40 is constituted by, for example, a microcomputer.

(Required refrigerant amount depending on pipe length)
Generally, the internal volume of the outdoor heat exchanger 3 is larger than the internal volume of the indoor heat exchanger 7. Also in the present embodiment, the internal volume of the outdoor heat exchanger 3 is assumed to be larger than the internal volume of the indoor heat exchanger 7. Therefore, in the refrigeration cycle circuit 100 of the air conditioner 200, there may be a difference between the necessary refrigerant filling amount during the cooling operation and the necessary refrigerant filling amount during the heating operation.
Specifically, when the connection length of the connection pipe 50 connecting the outdoor unit 30 and the indoor unit 70 is short due to the installation environment of the air conditioner 200, the outdoor heat exchanger 3 having a large internal volume is used as a condenser. In this case, that is, during the cooling operation, the required refrigerant charging amount increases. In this case, surplus refrigerant is generated during the heating operation. In order to temporarily store the surplus refrigerant, the refrigerant reservoir 5 is used.
On the other hand, when the connection length of the connection pipe 50 that connects the outdoor unit 30 and the indoor unit 70 is long, contrary to the above, the required refrigerant charging amount may increase during the heating operation.

FIG. 2 is a schematic diagram showing the amount of refrigerant required depending on the length of the connection pipe of the air conditioner 200. A necessary refrigerant amount line 201 in FIG. 2 represents the necessary refrigerant amount according to the length of the connection pipe 50 when the air conditioner 200 is in the heating operation. A necessary refrigerant amount line 202 in FIG. This shows the amount of refrigerant required during cooling operation.
An intersection 203 in FIG. 2 is an intersection of the line 201 during the heating operation and the necessary refrigerant amount line 202 during the cooling operation. Hereinafter, a case where the length of the connection pipe 50 is longer than the intersection 203 is referred to as “long”. The case where the length is less than the intersection 203 is called “short”. That is, the area 206 in FIG. 2 is “long” and the area 207 in FIG. 2 is “short”. The threshold value of whether the length is long or short is determined based on the length of the connection pipe 50 at the intersection 203.
According to FIG. 2, when the connection pipe 50 connecting the outdoor unit 30 and the indoor unit 70 is long, not only the difference in the internal volume between the indoor heat exchanger 7 and the outdoor heat exchanger 3 but also the outdoor unit 30 and the indoor unit. The influence of the amount of the refrigerant flowing through the connection pipe 50 that is a liquid pipe connecting to the pipe 70 is large.

Here, in the refrigeration cycle circuit during the heating operation, the high-temperature and high-pressure gaseous refrigerant exiting the compressor 1 is condensed in the indoor heat exchanger 7 to become liquid refrigerant. The liquid refrigerant flows through the piping from the indoor heat exchanger 7 to the decompression device 6. The longer the connection pipe 50 that connects the outdoor unit 30 and the indoor unit 70 depending on the installation environment of the air conditioner 200, the longer the pipe (liquid pipe) from the indoor heat exchanger 7 to the pressure reducing device 6 becomes. The amount of liquid refrigerant present in the pipe including the pipe 50 increases. This is the reason why the necessary refrigerant amount increases as the pipe length increases in the necessary refrigerant amount line 201 of FIG.

On the other hand, in the refrigeration cycle circuit 100 during the cooling operation, the high-temperature and high-pressure gaseous refrigerant discharged from the compressor is condensed in the outdoor heat exchanger 3 to become liquid refrigerant. The liquid refrigerant exiting the outdoor heat exchanger 3 becomes a gas-liquid two-phase refrigerant in the decompression device 6 installed in the outdoor unit 30. During the cooling operation, the refrigerant is present in the pipe as the liquid refrigerant between the outdoor heat exchanger 3 and the decompression device 6. The piping in this section is in the outdoor unit 30 and does not change depending on the installation environment of the air conditioner 200. Even if the connection pipe 50 that connects the outdoor unit 30 and the indoor unit 70 is long depending on the installation environment of the air conditioner 200, the refrigerant present in the pipe during the cooling operation is a gas-liquid two-phase refrigerant, so the pipe internal volume is Although it is the same as that in the heating operation, the mass of the necessary refrigerant is less than that in the heating operation. This is why the required refrigerant amount does not increase too much in the required refrigerant amount line 202 of FIG.

That is, during the cooling operation of the air conditioner 200, the liquid refrigerant that has exited the outdoor heat exchanger 3 is depressurized by the decompression device 6 to become a two-phase refrigerant and reaches the indoor heat exchanger 7 through the liquid pipe. During the heating operation, the liquid refrigerant that has exited the indoor heat exchanger 7 passes through the liquid piping as the liquid refrigerant, is depressurized by the decompression device 6, becomes a two-phase refrigerant, and reaches the outdoor heat exchanger 3. Therefore, when the mass of the refrigerant present in the liquid pipe as the liquid refrigerant is larger during the heating operation and the connection length of the connection pipe 50 that connects the outdoor unit 30 and the indoor unit 70 is longer than that during the cooling operation. However, the required refrigerant charge can be increased during heating operation. According to FIG. 2, when the connecting pipe 50 that connects the outdoor unit 30 and the indoor unit 70 beyond the intersection 203 is long, the amount of refrigerant required during heating operation increases. For example, the length of the connecting pipe 50 is B If so, excess refrigerant having a mass corresponding to the excess refrigerant amount 204 shown in FIG. 2 is generated during the cooling operation. Further, if the length of the connecting pipe 50 does not exceed the intersection 203, the amount of refrigerant required during cooling operation increases. For example, if the length of the connecting pipe 50 is A, the excess refrigerant amount shown in FIG. Excess refrigerant having a mass corresponding to 205 is generated during the heating operation.
Depending on the length of the connecting pipe 50, the refrigerant reservoir 5 is used to temporarily store surplus refrigerant generated during heating operation or cooling operation. The volume of the refrigerant reservoir 5 is designed in consideration of the amount of excess refrigerant shown in FIG.

(Operation when the air conditioner 200 is short)
FIG. 3 is a diagram of a refrigeration cycle circuit when the air conditioner 200 of FIG. 1 is short.
The operation of the refrigeration cycle circuit 100 when the air conditioner 200 is short will be described with reference to FIG. Here, the operation of the refrigeration cycle circuit 100 during operation (short time) when the length of the connecting pipe 50 connecting the indoor unit 70 and the outdoor unit 30 is short will be described.

(Short and heating operation)
Since it is during heating operation, the four-way valve 2 is switched to the position indicated by the broken line in FIG. That is, the discharge port side of the compressor 1 is connected to the indoor heat exchanger 7. The flow direction of the refrigerant flowing in the refrigeration cycle circuit 100 flows in the direction indicated by the broken line arrow 21 in FIG.
When the length is short, the switching valve 4 is switched to the position indicated by the solid line in FIG. That is, the refrigerant storage unit 5 side is connected to the indoor heat exchanger 7, and the decompression device 6 side is connected to the outdoor heat exchanger 3.
Then, as shown by the broken line arrow 21, the refrigerant is the compressor 1, the four-way valve 2, the indoor heat exchanger 7, the switching valve 4, the refrigerant reservoir 5, the decompression device 6, the switching valve 4, the outdoor heat exchanger 3, and the four-way. It circulates in the order of the valve 2 and returns to the compressor 1. According to this, heating operation is performed by the indoor heat exchanger 7 functioning as a condenser.

During the short and heating operation, the refrigerant flows in the direction indicated by the broken line arrow 21, and the refrigerant reservoir 5 is disposed in front of the decompression device 6 in the refrigeration cycle circuit 100. That is, it is arranged on the high pressure side of the refrigeration cycle circuit 100. Accordingly, the refrigerant condensed and liquefied by the indoor heat exchanger 7 flows into the refrigerant reservoir 5. When the length is short, the difference in the internal volume between the outdoor heat exchanger 3 and the indoor heat exchanger 7 greatly affects the amount of excess refrigerant (corresponding to the region 207 in FIG. 2). During the heating operation, the indoor heat exchanger 7 having a smaller internal volume acts as a condenser, so that excess liquid refrigerant is generated on the high-pressure side, and excess liquid refrigerant is stored in the refrigerant reservoir 5.

(Short-length and cooling operation)
During the cooling operation, the four-way valve 2 is switched to the position indicated by the solid line. The switching valve 4 remains in the position indicated by the solid line in FIG. Then, as shown by the solid line arrow 20, the refrigerant is the compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the switching valve 4, the decompression device 6, the refrigerant reservoir 5, the switching valve 4, the indoor heat exchanger 7, the four-way It circulates in the order of the valve 2 and returns to the compressor 1. According to this, the cooling operation is performed by the indoor heat exchanger 7 functioning as an evaporator.

During the above-described short and cooling operation, the refrigerant flows in the direction indicated by the solid line arrow 20, and the refrigerant reservoir 5 is disposed after the decompression device 6 in the refrigeration cycle circuit 100. That is, it is arranged on the low pressure side of the refrigeration cycle circuit 100. Therefore, the gas-liquid two-phase refrigerant that has passed through the decompression device 6 flows into the refrigerant reservoir 5.
According to the above configuration, the difference between the mass stored in the refrigerant storage unit 5 in the liquid state during the heating operation and the mass stored in the refrigerant storage unit 5 in the gas-liquid two-phase state during the cooling operation is The difference between the required refrigerant charge amount and the required refrigerant charge amount during the heating operation (for example, an amount corresponding to the excess refrigerant amount 205 if the length A of the connecting pipe 50 in FIG. 2 is used). The refrigerant storage unit 5 is designed so as to store the excess refrigerant that is the difference in the required refrigerant charge amount in consideration of the difference in internal volume between the outdoor heat exchanger 3 and the indoor heat exchanger 7 and the pipe length.

(Operation when the air conditioner 200 is long)
FIG. 4 is a diagram of the refrigeration cycle circuit 100 when the air conditioner 200 of FIG. 1 is long.
The operation of the refrigeration cycle circuit 100 when the air conditioner 200 is long will be described with reference to FIG. Here, the operation of the refrigeration cycle circuit 100 during operation (long time) when the length of the connecting pipe 50 connecting the indoor unit 70 and the outdoor unit 30 is long will be described.

(Long and heating operation)
Since the heating operation is being performed, the four-way valve 2 is switched to the position indicated by the broken line in FIG. That is, the discharge port side of the compressor 1 is connected to the indoor heat exchanger 7. The flow direction of the refrigerant flowing in the refrigeration cycle circuit 100 flows in the direction indicated by the broken line arrow 21 in FIG.
When long, the switching valve 4 is switched to the position indicated by the solid line in FIG. That is, the refrigerant storage unit 5 side is connected to the outdoor heat exchanger 3, and the decompression device 6 side is connected to the indoor heat exchanger 7. Then, as shown by the broken line arrow 21, the refrigerant is the compressor 1, the four-way valve 2, the indoor heat exchanger 7, the switching valve 4, the pressure reducing device 6, the refrigerant reservoir 5, the switching valve 4, the outdoor heat exchanger 3, and the four-way. It circulates in the order of the valve 2 and returns to the compressor 1. According to this, heating operation is performed by the indoor heat exchanger 7 functioning as a condenser.

In the long and heating operation, the refrigerant flows in the direction indicated by the broken line arrow 21, and the refrigerant reservoir 5 is disposed after the decompression device 6 in the refrigeration cycle circuit 100. That is, it is arranged on the low pressure side of the refrigeration cycle circuit 100. Therefore, the gas-liquid two-phase refrigerant that has passed through the decompression device 6 flows into the refrigerant reservoir 5. When the length is long, the connection pipe 50 that connects the outdoor unit 30 and the indoor unit 70 is long, and not only the difference in the internal volume between the indoor heat exchanger 7 and the outdoor heat exchanger 3, but also the connection that connects the outdoor unit 30 and the indoor unit 70. The influence of the state of the refrigerant flowing in the pipe 50 is increased. In the long heating operation, the indoor heat exchanger 7 having a smaller internal volume acts as a condenser. However, since the pipe (liquid pipe) between the indoor heat exchanger 7 and the decompression device 6 is long, The amount of a certain liquid refrigerant is large, and the necessary refrigerant charging amount during heating operation is large (corresponding to the region 206 in FIG. 2).

(Long and cooling operation)
During the cooling operation, the four-way valve 2 is switched to the position indicated by the solid line. The switching valve 4 remains in the position indicated by the solid line in FIG. Then, as shown by the solid line arrow 20, the refrigerant is the compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the switching valve 4, the refrigerant reservoir 5, the decompression device 6, the switching valve 4, the indoor heat exchanger 7, the four-way It circulates in the order of the valve 2 and returns to the compressor 1. According to this, the cooling operation is performed by the indoor heat exchanger 7 functioning as an evaporator.

In the long and cooling operation, the refrigerant flows in the direction indicated by the solid line arrow 20, and the refrigerant reservoir 5 is disposed in front of the decompression device 6 in the refrigeration cycle circuit 100. That is, it is arranged on the high pressure side of the refrigeration cycle circuit 100. Therefore, the refrigerant condensed and liquefied by the outdoor heat exchanger 3 flows into the refrigerant reservoir 5.
According to the above configuration, the difference between the mass stored in the refrigerant storage unit 5 in the gas-liquid two-phase state during the heating operation and the mass stored in the refrigerant storage unit 5 in the liquid state during the cooling operation is The difference between the required refrigerant charge amount and the required refrigerant charge amount during the heating operation (for example, an amount corresponding to the excess refrigerant amount 204 if the length B of the connecting pipe 50 in FIG. 2) is obtained. The refrigerant storage unit 5 takes into account the difference in internal volume between the outdoor heat exchanger 3 and the indoor heat exchanger 7 and the length of the connection pipe 50, and surplus liquid refrigerant generated during the cooling operation that is the difference in the required refrigerant charge amount. It is designed so that it can be stored.

According to the present embodiment, since the surplus refrigerant can be stored even if the length of the connection pipe 50 is short or long, the air conditioner 200 can be installed regardless of the installation conditions.
Further, in the conventional configuration, it is necessary to design the refrigeration cycle circuit 100 so that surplus refrigerant is generated only during either the cooling operation or the heating operation. For this reason, for example, in order to generate surplus refrigerant during the cooling operation, the amount of refrigerant required during the heating operation is the required refrigerant during the cooling operation even when variations in the piping length of the refrigeration cycle circuit 100 are considered. It has to be designed to be larger than the amount, and it is necessary to design so that the required amount of refrigerant can be filled in as much as the variation is taken into account, and the refrigerant storage portion has to be increased accordingly. However, according to the present embodiment, the surplus refrigerant can be stored either during the heating operation or during the cooling operation. Therefore, it is not necessary to increase the amount of the necessary refrigerant in consideration of the variation. Accordingly, it is possible to reduce the size of the refrigerant reservoir 5 accordingly. As a result, there is an advantage that the outdoor unit 30 can be downsized.

Embodiment 2. FIG.
In Embodiment 1, the configuration in which excess refrigerant generated during heating operation or cooling operation is stored by the refrigerant storage unit 5 has been described. However, in the present embodiment, the outdoor heat exchanger 3 is used instead of the refrigerant storage unit 5. A configuration in which a part of the above is used for storage of surplus refrigerant will be described.

FIG. 5 is a diagram of a refrigeration cycle circuit of the air conditioner 200 according to the second embodiment. In this air conditioner 200, a part of the outdoor heat exchanger 3 is used as a refrigerant reservoir instead of the refrigerant reservoir 5 described above. The operation of the air conditioner 200 as the refrigeration cycle circuit 100 is the same as that in the first embodiment.

When the length is short, the switching valve 4 is switched to the position indicated by the broken line in FIG. The piping from the first portion 8 of the outdoor heat exchanger 3 is connected to the switching valve 4, and the piping from the switching valve 4 returns to the second portion 9 of the outdoor heat exchanger 3 again. The piping exiting the second portion 9 is connected to the decompression device 6, and the piping exiting from the decompression device 6 is connected to the switching valve 4.

As in the first embodiment, during the short heating operation, surplus refrigerant is generated and liquid refrigerant is stored in the second portion 9 of the outdoor heat exchanger 3 arranged on the high-pressure side.
During the short and cooling operation, the gas-liquid two-phase refrigerant flows into the second portion 9 of the outdoor heat exchanger 3 disposed on the low pressure side. The second portion 9 is formed integrally with the first portion 8 as the outdoor heat exchanger 3. Therefore, the air-liquid two-phase refrigerant stored in the second portion 9 is air by a blower (not shown) that is installed in the air conditioner 200 and sends air for heat exchange to the outdoor heat exchanger 3. Heat exchanged and evaporated. That is, the first portion 8 and the second portion 9 function as an integral outdoor heat exchanger 3 during the short and cooling operation.

When long, the switching valve 4 is switched to the position shown by the solid line in FIG. The piping from the first portion 8 of the outdoor heat exchanger 3 is connected to the switching valve 4, the piping from the switching valve 4 is connected to the decompression device 6, and the piping from the decompression device 6 is the outdoor heat Connected to the second part of the exchanger 3.

Excess refrigerant is generated during the long and cooling operation, and the liquid refrigerant is stored in the second portion 9 of the outdoor heat exchanger 3 disposed on the high pressure side.
In the long and heating operation, the four-way valve 2 is switched to the broken line side in FIG. The gas-liquid two-phase refrigerant flows into the second portion 9 of the outdoor heat exchanger 3 arranged on the low pressure side. At this time, since the second portion 9 is formed integrally with the first portion 8 as the outdoor heat exchanger 3, a blower for sending air for heat exchange to the outdoor heat exchanger 3 (not shown) As a result, the gas-liquid two-phase refrigerant stored in the second portion 9 undergoes heat exchange with air and evaporates. In other words, the first portion 8 and the second portion 9 function as an integral outdoor heat exchanger 3 during the long and heating operation.
In the long and cooling operation, the four-way valve 2 is switched to the solid line side in FIG. Liquid refrigerant is stored in the second portion 9 of the outdoor heat exchanger 3 disposed on the high-pressure side.

According to the present embodiment, the second portion 9 which is a part of the outdoor heat exchanger 3 functions as the outdoor heat exchanger 3 during operation when no surplus refrigerant is generated, and surplus refrigerant is generated. It functions as a substitute for the refrigerant storage unit 5 during operation when the operation is performed. Therefore, since the surplus refrigerant storage part is formed using a part of the outdoor heat exchanger 3 without providing the refrigerant storage part 5 having the conventional configuration, the cost can be reduced and the outdoor unit 30 can be downsized. .

1 compressor, 2-way valve, 3 outdoor heat exchanger, 4 switching valve, 5 refrigerant reservoir, 6 decompression device, 7 indoor heat exchanger, 8 (outdoor heat exchanger 3) first part, 9 (outdoor 2nd part (of heat exchanger 3), 20 solid line arrow, 21 broken line arrow, 30 outdoor unit, 40 control device, 50 (between outdoor unit and indoor unit) connection piping, 51 (outdoor unit and indoor unit) Connecting pipe, 70 indoor unit, 100 refrigeration cycle circuit, 200 air conditioner, 201 (required refrigerant amount line during heating operation), 202 (refrigerant operation necessary refrigerant amount line), 203 intersection, 204 ( Excess refrigerant amount when long (long), 205 (extra refrigerant amount when short), 206 (long) area, 207 (short) area.

Claims (5)

An air conditioner that includes a refrigeration cycle circuit in which a compressor, an outdoor heat exchanger, a decompression device, an indoor heat exchanger, and a refrigerant reservoir are connected by refrigerant piping, and can be switched between heating operation and cooling operation. In the machine
An air conditioner comprising switching means for switching the arrangement of the refrigerant storage section between the outdoor heat exchanger and the pressure reducing device and between the indoor heat exchanger and the pressure reducing device. An outdoor unit on which the compressor, the outdoor heat exchanger, the pressure reducing device, the refrigerant reservoir, and the switching unit are mounted;
An indoor unit equipped with the indoor heat exchanger;
A connection pipe connecting the outdoor unit and the indoor unit,
The switching means is
When the length of the connection pipe is larger than a threshold, switching is performed so that the refrigerant reservoir is disposed between the outdoor heat exchanger and the pressure reducing device, and the length of the connection pipe is longer than the threshold. The air conditioner according to claim 1, wherein the air conditioner can be switched so that the refrigerant storage portion is disposed between the indoor heat exchanger and the pressure reducing device when small. Equipped with a control device,
The controller is
The air conditioner according to claim 2, wherein the threshold value is stored, and the switching unit is controlled based on the threshold value and the length of the connection pipe. The decompression device and the refrigerant reservoir are connected in series,
The switching means is
The air conditioner according to any one of claims 1 to 3, comprising a four-way valve. The air conditioner according to any one of claims 1 to 4, wherein the refrigerant reservoir is configured by a part of the outdoor heat exchanger.

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