JP7565879B2 - Air conditioners - Google Patents

Description

An embodiment of the present invention relates to an air conditioner.

Air conditioners, such as air conditioners, regulate the temperature inside a room by condensing and evaporating a refrigerant in a refrigeration cycle.

International Publication No. 2017-068649

This type of air conditioner would be beneficial if it were easy to make it energy efficient.

One example of the problem that this invention solves is to provide an air conditioner that is easy to make energy-efficient.

An air conditioner according to an embodiment of the present invention comprises an indoor heat exchanger, an outdoor heat exchanger, a first pipe, a second pipe, a compressor, a four-way valve, an expansion valve, a first bypass pipe, a heat exchange unit, a first valve, a second valve, and a control device. The first pipe connects the indoor heat exchanger and the outdoor heat exchanger, and a refrigerant flows through it. The second pipe connects the outdoor heat exchanger and the indoor heat exchanger, and the refrigerant flows through it. The compressor is provided in the first pipe and has an intake port for sucking in the refrigerant and an exhaust port for discharging the refrigerant. The four-way valve is provided in the first pipe and is capable of changing the direction in which the refrigerant flows. The expansion valve is provided in the second pipe. The first bypass piping has one end connected to the first piping between the indoor heat exchanger and the discharge port, and the other end connected to the second piping between the indoor heat exchanger and the expansion valve, through which the refrigerant can flow. The heat exchange unit exchanges heat between the first bypass piping and at least one of the first piping between the outdoor heat exchanger and the suction port and the second piping between the outdoor heat exchanger and the expansion valve. The first valve is provided in the first bypass piping between the one end and the heat exchange unit, and is capable of adjusting the amount of the refrigerant flowing through the first bypass piping. The second valve is provided in the first bypass piping between the other end and the heat exchange unit, and is capable of adjusting the amount of the refrigerant flowing through the first bypass piping. The control device controls the four-way valve, the expansion valve, the first valve, and the second valve.

In the air conditioner, for example, the heat exchange unit has a first heat exchanger and a second heat exchanger. The first heat exchanger exchanges heat between the first pipe between the outdoor heat exchanger and the intake port and the first bypass pipe. The second heat exchanger exchanges heat between the second pipe between the outdoor heat exchanger and the expansion valve and the first bypass pipe. The first valve is provided in the first bypass pipe between the one end and the first heat exchanger. The second valve is provided in the first bypass pipe between the other end and the second heat exchanger.

The air conditioner includes, for example, a three-way valve, a second bypass pipe, and an on-off valve. The three-way valve is provided in the first bypass pipe and is capable of changing the direction in which the refrigerant flows. The second bypass pipe is connected to the first pipe between the compressor and the four-way valve and to the three-way valve, and allows the refrigerant to flow. The on-off valve is provided in the first pipe between the one end and the four-way valve.

In the air conditioner, for example, the first heat exchanger and the second heat exchanger are heat storage materials.

The above air conditioner makes it possible to obtain an air conditioner that is easy to save energy.

FIG. 1 is a refrigerant system diagram that illustrates an air conditioner according to an embodiment during cooling operation. FIG. 2 is a refrigerant system diagram that illustrates the air conditioner during heating operation according to the embodiment. FIG. 3 is a block diagram showing the functional configuration of the air conditioner of the embodiment. FIG. 4 is a flowchart showing an example of cooling operation control of the air conditioner of the embodiment. FIG. 5 is a flowchart illustrating an example of heating operation control of the air conditioner according to the embodiment. FIG. 6 is a refrigerant system diagram that illustrates the air conditioner during dehumidification operation according to the embodiment. FIG. 7 is a block diagram illustrating an example of a hardware configuration of the control device according to the embodiment.

One embodiment will be described below with reference to Figures 1 to 7. Note that in this specification, components according to the embodiment and descriptions of the components may be described using multiple expressions. The components and their descriptions are merely examples and are not limited by the expressions in this specification. The components may also be identified by names different from those in this specification. The components may also be described using expressions different from those in this specification.

Figure 1 is a refrigerant system diagram that shows an outline of the air conditioner 10 during cooling operation in this embodiment. The air conditioner 10 is, for example, a home air conditioner. Note that the air conditioner 10 is not limited to this example and may be another type of air conditioner, such as a commercial air conditioner.

As shown in FIG. 1, the air conditioner 10 has an outdoor unit 11, an indoor unit 12, refrigerant piping 13, and a control device 14. The outdoor unit 11 is placed, for example, outdoors. The indoor unit 12 is placed, for example, indoors.

The air conditioner 10 has a refrigeration cycle in which an outdoor unit 11 and an indoor unit 12 are connected by refrigerant piping 13. Refrigerant flows between the outdoor unit 11 and the indoor unit 12 through the refrigerant piping 13. In addition, the outdoor unit 11 and the indoor unit 12 are electrically connected to each other by, for example, electrical wiring.

The outdoor unit 11 has an outdoor heat exchanger 21, an outdoor blower fan 22, a compressor 23, an accumulator 24, a four-way valve 25, a first expansion valve 31, a second expansion valve 32, a third expansion valve 33, a three-way valve 34, and an on-off valve 35. The indoor unit 12 has an indoor heat exchanger 41 and an indoor blower fan 42.

The refrigerant piping 13 is a pipe made of a metal such as copper or aluminum. The refrigerant piping 13 has a first piping 51, a second piping 52, a first bypass piping 53, and a second bypass piping 54. The first piping 51 connects the indoor heat exchanger 41 and the outdoor heat exchanger 21. The compressor 23, the accumulator 24, the four-way valve 25, the three-way valve 34, and the on-off valve 35 are provided in the first piping 51. The second piping 52 connects the outdoor heat exchanger 21 and the indoor heat exchanger 41. The first expansion valve 31 is provided in the second piping 52. The first bypass piping 53 is connected to the first piping 51 and the second piping 52. The second expansion valve 32, the third expansion valve 33, and the three-way valve 34 are provided in the first bypass piping 53. The second bypass pipe 54 is connected to the first pipe 51 and the first bypass pipe 53.

In cooling operation, the refrigerant flows from the indoor heat exchanger 41 to the outdoor heat exchanger 21 through the first pipe 51, and flows from the outdoor heat exchanger 21 to the indoor heat exchanger 41 through the second pipe 52. In cooling operation, the on-off valve 35 is open. In cooling operation, when the second expansion valve 32 and the third expansion valve 33 are opened, a portion of the refrigerant flows through the first bypass pipe 53. The arrows in FIG. 1 show an example of the flow of the refrigerant during cooling operation.

Figure 2 is a refrigerant system diagram that shows the air conditioner 10 during heating operation of this embodiment. As shown in Figure 2, during heating operation, the refrigerant flows from the outdoor heat exchanger 21 to the indoor heat exchanger 41 through the first pipe 51, and flows from the indoor heat exchanger 41 to the outdoor heat exchanger 21 through the second pipe 52. During heating operation, the on-off valve 35 is in an open state. During heating operation, when the second expansion valve 32 and the third expansion valve 33 are opened, a portion of the refrigerant flows through the first bypass pipe 53. The arrows in Figure 2 show an example of the flow of the refrigerant during heating operation.

The outdoor heat exchanger 21 of the outdoor unit 11 acts as an evaporator to absorb heat from the refrigerant or as a condenser to release heat from the refrigerant depending on the direction of refrigerant flow. The outdoor blower fan 22 blows air toward the outdoor heat exchanger 21, promoting heat exchange between the refrigerant and air in the outdoor heat exchanger 21. In other words, the outdoor blower fan 22 generates an airflow that exchanges heat with the outdoor heat exchanger 21.

The compressor 23 has an intake port 23a and an exhaust port 23b. The compressor 23 draws in the refrigerant from the intake port 23a and exhausts the compressed refrigerant from the exhaust port 23b. In this way, the compressor 23 compresses the refrigerant in the refrigeration cycle and causes the refrigerant to circulate.

The accumulator 24 is connected to the suction port 23a of the compressor 23. The accumulator 24 separates the gaseous refrigerant from the liquid refrigerant. This allows the compressor 23 to suck the gaseous refrigerant that has passed through the accumulator 24 from the suction port 23a. The accumulator 24 is configured integrally with the compressor 23, and can serve as the suction port of the compressor 23.

The four-way valve 25 is connected to the outdoor heat exchanger 21, the indoor heat exchanger 41, the discharge port 23b of the compressor 23, and the accumulator 24 (the suction port 23a of the compressor 23). The four-way valve 25 switches the flow paths connected to the outdoor heat exchanger 21, the indoor heat exchanger 41, the discharge port 23b of the compressor 23, and the accumulator 24 during heating operation and cooling operation, changing the direction in which the refrigerant flows. The four-way valve 25 is also called a switching valve.

As shown in FIG. 1, during cooling operation, the four-way valve 25 connects the outdoor heat exchanger 21 to the discharge port 23b of the compressor 23. Furthermore, during cooling operation, the four-way valve 25 connects the indoor heat exchanger 41 to the accumulator 24. As a result, the refrigerant compressed by the compressor 23 flows to the outdoor heat exchanger 21, and the refrigerant evaporated in the indoor heat exchanger 41 flows to the accumulator 24.

As shown in FIG. 2, during heating operation, the four-way valve 25 connects the outdoor heat exchanger 21 and the accumulator 24. Furthermore, during heating operation, the four-way valve 25 connects the indoor heat exchanger 41 and the discharge port 23b of the compressor 23. As a result, the refrigerant compressed by the compressor 23 flows to the indoor heat exchanger 41, and the refrigerant evaporated in the outdoor heat exchanger 21 flows to the accumulator 24.

The first expansion valve 31, the second expansion valve 32, and the third expansion valve 33 are, for example, electromagnetic expansion valves. Note that the first expansion valve 31, the second expansion valve 32, and the third expansion valve 33 may be other expansion valves. The first expansion valve 31, the second expansion valve 32, and the third expansion valve 33 adjust the amount of refrigerant passing through by controlling the opening degree. The second expansion valve 32 is an example of a first valve, and the third expansion valve 33 is an example of a second valve.

The indoor heat exchanger 41 of the indoor unit 12 absorbs heat as an evaporator or releases heat as a condenser depending on the direction of refrigerant flow. The indoor blower fan 42 blows air toward the indoor heat exchanger 41, promoting heat exchange between the indoor heat exchanger 41 and the air. In other words, the indoor blower fan 42 generates an airflow that exchanges heat with the indoor heat exchanger 41.

In the air conditioner 10 in which the elements are arranged as described above, the first piping 51 has regions 51a, 51b, 51c, and 51d. Region 51a is a portion of the first piping 51 between the indoor heat exchanger 41 and the four-way valve 25. Region 51b is a portion of the first piping 51 between the four-way valve 25 and the accumulator 24. Region 51c is a portion of the first piping 51 between the discharge port 23b of the compressor 23 and the four-way valve 25. Region 51d is a portion of the first piping 51 between the four-way valve 25 and the outdoor heat exchanger 21.

The second piping 52 has an area 52a and an area 52b. The area 52a is a part of the second piping 52 between the outdoor heat exchanger 21 and the first expansion valve 31. The area 52b is a part of the second piping 52 between the first expansion valve 31 and the indoor heat exchanger 41.

The first bypass pipe 53 has one end 53a and the other end 53b. The one end 53a is connected to the first pipe 51 between the indoor heat exchanger 41 and the discharge port 23b. That is, the one end 53a is provided in the region 51a of the first pipe 51. The other end 53b is connected to the second pipe 52 between the indoor heat exchanger 41 and the first expansion valve 31. That is, the other end 53b is provided in the region 52b of the second pipe 52.

The first bypass pipe 53 is provided with a second expansion valve 32, a three-way valve 34, and a third expansion valve 33. The second expansion valve 32 is provided near one end 53a. The three-way valve 34 is provided on the other end 53b side of the second expansion valve 32. The third expansion valve 33 is provided on the other end 53b side of the three-way valve 34. The third expansion valve 33 is provided near the other end 53b.

The second bypass pipe 54 has one end 54a and the other end 54b. The one end 54a is connected to the first pipe 51 between the suction port 23a and the four-way valve 25. That is, the one end 54a is provided in the region 51b of the first pipe 51. The other end 54b is connected to the three-way valve 34. That is, the other end 53b is provided in the three-way valve 34.

The three-way valve 34 switches the flow paths connected to the portion between one end 53a of the first bypass pipe 53 and the three-way valve 34, the portion between the other end 53b of the first bypass pipe 53 and the three-way valve 34, and the second bypass pipe 54, and changes the direction in which the refrigerant flows. Such a three-way valve 34 can allow the refrigerant to flow between the portion between the other end 53b of the first bypass pipe 53 and the three-way valve 34 and the region 51b of the first pipe 51. The three-way valve 34 is also called a switching valve.

The on-off valve 35 is provided in the region 51a of the first pipe 51. When the on-off valve 35 is open, it allows the refrigerant to flow through the region 51a, and when the on-off valve 35 is closed, it blocks the refrigerant from flowing through the region 51a.

In addition, the outdoor unit 11 of this embodiment has a heat exchange section 45. The heat exchange section 45 has a first heat exchanger 62 and a second heat exchanger 63.

The first heat exchanger 62 and the second heat exchanger 63 are, for example, heat storage materials. The heat storage material has a latent heat storage material filled in a block-shaped container. The latent heat storage material is, for example, calcium chloride. The first heat exchanger 62 and the second heat exchanger 63 may have other latent heat storage materials. The first heat exchanger 62 and the second heat exchanger 63 in this embodiment are, for example, heat storage materials that can be used in a temperature range of about 10°C to about 100°C.

The first heat exchanger 62 and the second heat exchanger 63 are not limited to the above-mentioned examples, and may be, for example, other heat storage materials such as sensible heat storage materials, or may be heat storage materials that can be used in other temperature ranges. In addition, the first heat exchanger 62 and the second heat exchanger 63 may be heat storage materials different from each other.

The first heat exchanger 62 is thermally connected to the region 51d of the first pipe 51 between the outdoor heat exchanger 21 and the intake port 23a, and to the first bypass pipe 53. For example, the region 51d of the first pipe 51 and the first bypass pipe 53 are spaced apart from each other and pass through the first heat exchanger 62.

The first heat exchanger 62 configured in this manner exchanges heat between the region 51d of the first pipe 51 and the first bypass pipe 53. That is, in the first heat exchanger 62, heat exchange occurs between the refrigerant in the region 51d of the first pipe 51 and the refrigerant in the first bypass pipe 53.

The first heat exchanger 62 has a larger amount of heat that can be stored (heat storage capacity) than the area 51d and the first bypass pipe 53. In addition, the area 51d and the first bypass pipe 53 are made of metal and are in close contact with the latent heat storage material of the first heat exchanger 62. For this reason, heat conduction is likely to occur between the area 51d and the first bypass pipe 53 and the latent heat storage material of the first heat exchanger 62.

The second heat exchanger 63 is thermally connected to the region 52a of the second pipe 52 between the outdoor heat exchanger 21 and the first expansion valve 31 and to the first bypass pipe 53. For example, the region 52a and the first bypass pipe 53 are separated from each other and pass through the second heat exchanger 63. Therefore, the second heat exchanger 63 thermally connects the region 52a and the first bypass pipe 53 to each other. The second heat exchanger 63 configured in this way exchanges heat between the region 52a of the second pipe 52 and the first bypass pipe 53. That is, in the second heat exchanger 63, heat exchange is performed between the refrigerant in the region 52a and the refrigerant in the first bypass pipe 53.

The second heat exchanger 63 has a larger heat storage capacity than the first bypass pipe 53 and the area 52b. In addition, the first bypass pipe 53 and the area 52a are made of metal and are in close contact with the latent heat storage material of the second heat exchanger 63. For this reason, heat conduction is likely to occur between the first bypass pipe 53 and the area 52a and the latent heat storage material of the second heat exchanger 63.

The air conditioner 10 also has temperature sensors 71A-71J and a human presence sensor 72.

The temperature sensor 71A is disposed, for example, in the housing of the outdoor unit 11. The temperature sensor 71A detects the outside air temperature of the outdoor environment in which the outdoor unit 11 is disposed.

The temperature sensor 71B is provided in the outdoor heat exchanger 21. The temperature sensor 71B detects the temperature of the refrigerant flowing through the outdoor heat exchanger 21. For example, the temperature sensor 71B is disposed at a position where the saturation temperature of the refrigerant flowing through the outdoor heat exchanger 21 can be obtained.

The temperature sensor 71C is disposed, for example, in the housing of the indoor unit 12. The temperature sensor 71C detects the temperature (room temperature) of the room in which the indoor unit 12 is disposed.

Temperature sensor 71D is provided on the four-way valve 25 side of the indoor heat exchanger 41 in the indoor unit 12, and detects the temperature of the refrigerant on the four-way valve 25 side of the indoor heat exchanger 41. Temperature sensor 71E is provided in the indoor heat exchanger 41. Temperature sensor 71E detects the temperature of the refrigerant flowing through the indoor heat exchanger 41. Temperature sensor 71F is provided on the first expansion valve 31 side of the indoor heat exchanger 41 in the indoor unit 12, and detects the temperature of the refrigerant on the first expansion valve 31 side of the indoor heat exchanger 41. For example, temperature sensors 71D to 71F are positioned so that the saturation temperature of the refrigerant can be obtained.

The temperature sensor 71G is provided in the first heat exchanger 62. The temperature sensor 71G detects the temperature of the first heat exchanger 62.

The temperature sensor 71H is provided in the second heat exchanger 63. The temperature sensor 71H detects the temperature of the second heat exchanger 63.

The temperature sensor 71I is provided in the region 51b of the first pipe 51, near the accumulator 24. The temperature sensor 71H detects the temperature of the refrigerant flowing through the region 51b, near the accumulator 24.

The temperature sensor 71J is provided in the region 52a of the second pipe 52 between the second heat exchanger 63 and the first expansion valve 31. The temperature sensor 71J detects the temperature of the refrigerant flowing through the region 52a near the second heat exchanger 63.

The human presence sensor 72 is provided in the indoor unit 12. The human presence sensor 72 detects humans (animals) in the room in which the indoor unit 12 is installed. The human presence sensor 72 is also referred to as a human detection sensor.

The control device 14 has, for example, an outdoor control device 14a and an indoor control device 14b. The outdoor control device 14a and the indoor control device 14b are electrically connected to each other by electrical wiring. At least one of the outdoor control device 14a and the indoor control device 14b is, for example, a computer having a control device such as a CPU (Central Processing Unit) or a microcontroller, a ROM (Read Only Memory), a RAM (Random Access Memory), and a storage device such as a flash memory. Note that the control device 14 is not limited to this example. For example, the control device 14 may have only one of the outdoor control device 14a and the indoor control device 14b.

The outdoor control device 14a controls the outdoor blower fan 22, compressor 23, four-way valve 25, first expansion valve 31, second expansion valve 32, third expansion valve 33, three-way valve 34, and opening/closing valve 35 of the outdoor unit 11. The indoor control device 14b controls the indoor blower fan 42 of the indoor unit 12.

The control device 14 controls the outdoor unit 11 and the indoor unit 12, so that the air conditioner 10 performs cooling operation, heating operation, dehumidification operation, and other operations. The indoor control device 14b may receive signals, for example, from a remote controller, or may receive signals from an information terminal such as a smartphone via a communication device.

Figure 3 is a block diagram showing the functional configuration of the air conditioner 10 of this embodiment. As shown in Figure 3, the air conditioner 10 of this embodiment further has an outdoor fan drive circuit 81, an indoor fan drive circuit 82, an inverter circuit 83, a four-way valve drive circuit 84, a first expansion valve drive circuit 85, a second expansion valve drive circuit 86, a third expansion valve drive circuit 87, a three-way valve drive circuit 88, and an on-off valve drive circuit 89.

The outdoor fan drive circuit 81 is a drive circuit for the outdoor blower fan 22. The indoor fan drive circuit 82 is a drive circuit for the indoor blower fan 42. The inverter circuit 83 inverter controls the compressor 23 and changes the frequency of the compressor 23. The inverter circuit 83 is, for example, a PAM (Pulse Amplitude Modulation) type inverter circuit. Note that the inverter circuit 83 is not limited to this example.

The four-way valve drive circuit 84 is a drive circuit for the four-way valve 25. The first expansion valve drive circuit 85 is a drive circuit for the first expansion valve 31. The second expansion valve drive circuit 86 is a drive circuit for the second expansion valve 32. The third expansion valve drive circuit 87 is a drive circuit for the third expansion valve 33. The three-way valve drive circuit 88 is a drive circuit for the three-way valve 34. The on-off valve drive circuit 89 is a drive circuit for the on-off valve 35.

The control device 14 is connected to the temperature sensors 71A-71J, the human presence sensor 72, the outdoor fan drive circuit 81, the indoor fan drive circuit 82, the inverter circuit 83, the four-way valve drive circuit 84, the first expansion valve drive circuit 85, the second expansion valve drive circuit 86, the third expansion valve drive circuit 87, the three-way valve drive circuit 88, and the on-off valve drive circuit 89. The control device 14 includes a temperature acquisition unit 91, an operation switching unit 92, an outdoor fan control unit 93, an indoor fan control unit 94, a compressor control unit 95, and a valve control unit 96.

The temperature acquisition unit 91 uses the temperature sensors 71A to 72J to acquire the outside air temperature, the refrigerant temperature, the temperature of the first heat exchanger 62, and the temperature of the second heat exchanger 63. For example, the temperature acquisition unit 91 calculates the outside air temperature, the refrigerant temperature, the temperature of the first heat exchanger 62, and the temperature of the second heat exchanger 63 from the output signals of the temperature sensors 71A to 71J.

The operation switching unit 92 switches the air conditioner 10 between cooling operation, heating operation, and dehumidification operation. The operation switching unit 92 may also switch the operation of the air conditioner 10 to another operation mode. A human presence sensor 72 is connected to the operation switching unit 92.

The outdoor fan control unit 93 controls the outdoor blower fan 22. For example, the outdoor fan control unit 93 controls the outdoor fan drive circuit 81 to control the rotation speed of the motor of the outdoor blower fan 22.

The indoor fan control unit 94 controls the indoor blower fan 42. For example, the indoor fan control unit 94 controls the rotation speed of the motor of the indoor blower fan 42 by controlling the indoor fan drive circuit 82.

The compressor control unit 95 controls the compressor 23. For example, the compressor control unit 95 controls the frequency (operating frequency) of the compressor 23 by controlling the inverter circuit 83.

The valve control unit 96 controls the four-way valve 25, the first expansion valve 31, the second expansion valve 32, the third expansion valve 33, the three-way valve 34, and the on-off valve 35. The valve control unit 96 drives the actuator of the four-way valve 25 by controlling the four-way valve drive circuit 84, and changes the direction in which the refrigerant flows through the four-way valve 25. The valve control unit 96 changes the opening degree of the first expansion valve 31, the second expansion valve 32, and the third expansion valve 33 by controlling the first expansion valve drive circuit 85, the second expansion valve drive circuit 86, and the third expansion valve drive circuit 87. The valve control unit 96 changes the direction in which the refrigerant flows through the three-way valve 34 by controlling the three-way valve drive circuit 88. The valve control unit 96 changes the state (open state, closed state) of the on-off valve 35 by controlling the on-off valve drive circuit 89.

The cooling operation, heating operation, and dehumidification operation of the air conditioner 10 of this embodiment are described below. Note that the air conditioner 10 is not limited to the cooling operation, heating operation, and dehumidification operation, and can perform other operations such as dehumidification operation and defrosting operation. Also, the cooling operation, dehumidification operation, and heating operation of the air conditioner 10 are not limited to the examples described below.

Figure 4 is a flow chart showing an example of cooling operation control of the air conditioner 10 of this embodiment. For example, when the air conditioner 10 is started and the cooling operation starts simultaneously, the outdoor blower fan 22, the compressor 23, and the indoor blower fan 42 are stopped. In this case, the outdoor fan control unit 93, the indoor fan control unit 94, and the compressor control unit 95 start the outdoor blower fan 22, the compressor 23, and the indoor blower fan 42 at the start of the cooling operation.

During cooling operation, the outdoor fan control unit 93 adjusts the rotation speed of the outdoor blower fan 22. The indoor fan control unit 94 adjusts the rotation speed of the indoor blower fan 42. The compressor control unit 95 adjusts the operating frequency of the compressor 23. For example, the indoor fan control unit 94 controls the indoor blower fan 42 between weak wind (low speed) operation and strong wind (high speed) operation in response to the air temperature in the room where the indoor unit 12 is installed or a signal input from a remote controller.

4, when the cooling operation is started, the valve control unit 96 controls the four-way valve drive circuit 84 and the three-way valve drive circuit 88 to change the direction of the refrigerant flow to the four-way valve 25 and the three-way valve 34 (S501). At this time, the valve control unit 96 also opens the on-off valve 35. As a result, the outdoor heat exchanger 21 and the discharge port 23b of the compressor 23 are connected, and the indoor heat exchanger 41 and the accumulator 24 (the suction port 23a of the compressor 23) are connected. That is, the control device 14 executes the cooling operation to control the four-way valve 25 so that the refrigerant flows from the discharge port 23b of the compressor 23 to the outdoor heat exchanger 21. Furthermore, the valve control unit 96 opens the second expansion valve 32 and the third expansion valve 33. As a result, the area 51a of the first pipe 51 and the area 52b of the second pipe 52 are connected via the first bypass pipe 53. In this case, no refrigerant flows through the second bypass pipe 54.

Next, the operation switching unit 92 determines whether or not to end the cooling operation (S502). For example, if the air conditioner 10 receives a stop signal or a switch signal to another operation from the remote controller, the operation switching unit 92 determines that the cooling operation is to end (S502: Yes) and ends the cooling operation.

If the cooling operation does not end (S502: No), the valve control unit 96 determines whether the return superheat degree (Su-Th2) is 3°C (S503). Temperature Su is the temperature detected by temperature sensor 71I, and temperature Th2 is the temperature detected by temperature sensor 71G.

If the return superheat degree (Su-Th2) is not 3°C (S503: No), the valve control unit 96 controls the second expansion valve drive circuit 86 and the third expansion valve drive circuit 87 to adjust the opening degree of the second expansion valve 32 and the third expansion valve 33 (S504). The valve control unit 96 adjusts the opening degree of the second expansion valve 32 and the third expansion valve 33 so that the return superheat degree (Su-Th2) is 3°C. If the return superheat degree (Su-Th2) is 3°C in S503 (S503: Yes), S504 is omitted.

Next, the valve control unit 96 determines whether the supercooling (Tc1-Tc) is equal to or greater than 6°C (S505). Temperature Tc1 is the temperature detected by temperature sensor 71H, and temperature Tc is the temperature detected by temperature sensor 71B.

If the subcooling (Tc1-Tc) is 6°C or higher (S505: Yes), the outdoor fan control unit 93 controls the outdoor fan drive circuit 81 to stop the outdoor blower fan 22 from blowing air (S506). This is because the refrigerant has been cooled too much in the outdoor heat exchanger 21. If the subcooling (Tc1-Tc) does not fall below 6°C (S507: No), the outdoor blower fan 22 continues to stop blowing air (S506).

When the subcooling (Tc1-Tc) falls below 6°C due to the stop of the outdoor blower fan 22 (S507: Yes), the outdoor fan control unit 93 controls the outdoor fan drive circuit 81 to start (resume) the outdoor blower fan 22 blowing air (S508). When the subcooling (Tc1-Tc) falls below 6°C in S505 (S505: No), S506 to S508 are omitted.

S502 to S508 are repeated until cooling operation ends.

As shown in FIG. 1, in cooling operation, the high-temperature, high-pressure gaseous refrigerant discharged from the discharge port 23b of the compressor 23 passes through the four-way valve 25 and the first heat exchanger 62, and dissipates heat in the outdoor heat exchanger 21. The medium-temperature, medium-pressure liquid refrigerant condensed in the outdoor heat exchanger 21 passes through the second heat exchanger 63, and is depressurized by the first expansion valve 31. At this time, the refrigerant dissipates heat in each of the first heat exchanger 62 and the second heat exchanger 63. The dissipated heat is transferred to the first heat exchanger 62 and the second heat exchanger 63.

A portion of the low-temperature, low-pressure liquid refrigerant decompressed by the first expansion valve 31 absorbs heat in the indoor heat exchanger 41. The gaseous refrigerant evaporated by the indoor heat exchanger 41 passes through the on-off valve 35 and the four-way valve 25 and returns to the suction port 23a of the compressor 23. A portion of the low-temperature, low-pressure liquid refrigerant decompressed by the first expansion valve 31 flows from the other end 53b of the first bypass piping 53 to the first bypass piping 53. The refrigerant that flows into the first bypass piping 53 passes through the third expansion valve 33, the three-way valve 34, the second heat exchanger 63, the first heat exchanger 62, and the second expansion valve 32, and flows from one end 53a of the first bypass piping 53 to the first piping 51. At this time, the refrigerant absorbs heat in each of the first heat exchanger 62 and the second heat exchanger 63. That is, the refrigerant passing through the first bypass pipe 53 exchanges heat with the refrigerant flowing through the region 52a of the second pipe 52 and the refrigerant flowing through the region 51d of the first pipe 51 via the second heat exchanger 63 and the first heat exchanger 62, respectively. As a result, the refrigerant passing through the first bypass pipe 53 is heated and gasified (evaporated). The refrigerant that has flowed into the first pipe 51 passes through the on-off valve 35 and the four-way valve 25 and returns to the suction port 23a of the compressor 23.

In addition, when the outdoor blower fan 22 stops blowing air in S506 above, the amount of heat exchanged by the refrigerant in the outdoor heat exchanger 21 decreases, and the amount of gasification decreases, but at least the amount of heat stored in the second heat exchanger 63 increases accordingly. Therefore, the refrigerant is further gasified as it flows through the first bypass piping 53. In this case, the outdoor blower fan 22 no longer consumes power, and energy conservation of the air conditioner 10 is achieved.

The capacity of the air conditioner 10 may be set according to the magnitude of the corresponding degree of superheat (Te1-Te). In addition, in the above cooling operation control, for example, when the air conditioner 10 is operating at low capacity (minimum capacity) within the specified capacity range, the air volume (rotation speed) of the indoor blower fan 42 is set to a constant air volume with an SHF of 0.65. This maintains the capacity of the air conditioner 10 at a low capacity within the specified capacity range, and prevents it from becoming high capacity. Here, if the air volume of the indoor blower fan 42 is increased, the SHF approaches 1. This also makes it easier to control the second expansion valve 32 and the third expansion valve 33 when the air conditioner 10 is operating at low capacity.

Figure 5 is a flowchart showing an example of heating operation control of the air conditioner 10 of this embodiment. For example, when the air conditioner 10 is started and the heating operation starts at the same time, the outdoor blower fan 22, the compressor 23, and the indoor blower fan 42 are stopped. In this case, the outdoor fan control unit 93, the indoor fan control unit 94, and the compressor control unit 95 start the outdoor blower fan 22, the compressor 23, and the indoor blower fan 42 at the start of the heating operation. During low capacity in the heating operation, for example, the operating frequency of the compressor 23 is the minimum frequency of the compressor 23 plus a specified value (for example, 5 Hz). This prevents the compressor 23 from repeatedly operating and stopping during low capacity. In other words, continuous operation of the compressor 23 is possible.

5, when the heating operation is started, the valve control unit 96 controls the four-way valve drive circuit 84 and the three-way valve drive circuit 88 to change the direction of the refrigerant flow to the four-way valve 25 and the three-way valve 34 (S601). At this time, the valve control unit 96 opens the on-off valve 35. This connects the indoor heat exchanger 41 to the discharge port 23b of the compressor 23, and connects the outdoor heat exchanger 21 to the accumulator 24 (the suction port 23a of the compressor 23). That is, the control device 14 executes the heating operation to control the four-way valve 25 so that the refrigerant flows from the discharge port 23b of the compressor 23 through the on-off valve 35 to the indoor heat exchanger 41. In addition, the four-way valve 25 and the suction port 23a of the compressor 23 are connected via the region 51b of the first piping 51. In addition, at this time, the second expansion valve 32 and the third expansion valve 33 are closed. In addition, when the second expansion valve 32 and the third expansion valve 33 are in an open state, the three-way valve 34 is controlled so that a portion of the refrigerant flowing through the on-off valve 35 flows from the region 51a of the first pipe 51 through the first bypass pipe 53 and into the region 52b of the second pipe 52.

Next, the operation switching unit 92 determines whether or not to end the heating operation (S602). For example, if the air conditioner 10 receives a stop signal or a switch signal to another operation from the remote controller, the operation switching unit 92 determines that the heating operation is to end (S602: Yes) and ends the heating operation.

If the heating operation does not end (S602: No), the valve control unit 96 determines whether the degree of subcooling (Te2-Te) is 7°C or higher (S603). Temperature Te2 is the temperature detected by temperature sensor 71F, and temperature Te is the temperature detected by temperature sensor 71E.

If the degree of subcooling (Te2-Te) is not 7°C or higher (S603: No), the valve control unit 96 returns to S602. If the degree of subcooling (Te2-Te) is 7°C or higher (S603: Yes), there is a possibility that liquid refrigerant has accumulated in the indoor heat exchanger 41, i.e., so-called overcharging, has occurred, so the valve control unit 96 opens the second expansion valve 32 and the third expansion valve 33 (S604). As a result, refrigerant flows into the first bypass pipe 53, and the amount of refrigerant flowing into the indoor heat exchanger 41 is reduced accordingly, eliminating the overcharging of the indoor heat exchanger 41.

The valve control unit 96 determines whether the degree of subcooling (Te2-Te) is less than 7°C (S605). If the degree of subcooling (Te2-Te) is not less than 7°C (S605: No), the second expansion valve 32 and the third expansion valve 33 are maintained open (S604). If the degree of subcooling (Te2-Te) is less than 7°C (S605: Yes), the valve control unit 96 closes the second expansion valve 32 and the third expansion valve 33 (S606). This stops refrigerant flowing through the first bypass pipe 53.

2, in heating operation, when the second expansion valve 32 and the third expansion valve 33 are open, the refrigerant flows as follows. That is, a part of the high-temperature, high-pressure gaseous refrigerant discharged from the discharge port 23b of the compressor 23 flows through the indoor heat exchanger 41, the first expansion valve 31, and the first heat exchanger 62 to the outdoor heat exchanger 21. A part of the high-temperature, high-pressure gaseous refrigerant discharged from the discharge port 23b of the compressor 23 flows from one end 53a of the first bypass piping 53 through the first bypass piping 53, and from the other end 53b of the first bypass piping 53 to the region 52b of the second piping 52. In the first bypass piping 53, the refrigerant passes through the second expansion valve 32, the first heat exchanger 62, the second heat exchanger 63, the three-way valve 34, and the third expansion valve 33. At this time, the refrigerant dissipates heat in the first heat exchanger 62 and the second heat exchanger 63. The dissipated heat is transferred to the first heat exchanger 62 and the second heat exchanger 63.

The refrigerant flowing through the second pipe 52 flows through the first expansion valve 31 and the second heat exchanger 63 to the outdoor heat exchanger 21. The refrigerant flowing out of the outdoor heat exchanger 21 returns to the compressor 23 through the first heat exchanger 62 and the four-way valve 25 in the first pipe 51. The refrigerant absorbs heat when passing through the second heat exchanger 63 in the second pipe 52 and when passing through the first heat exchanger 61 in the first pipe 51. That is, the refrigerant flowing through the region 52a of the second pipe 52 exchanges heat with the refrigerant passing through the first bypass pipe 53 through the second heat exchanger 63. Also, the refrigerant flowing through the region 51d of the first pipe 51 exchanges heat with the refrigerant passing through the first bypass pipe 53 through the first heat exchanger 62. As a result, the refrigerant flowing through the region 52a of the second pipe 52 and the refrigerant flowing through the region 51d of the first pipe 51 are heated, their pressure increases, and they are gasified and returned to the compressor 23. At this time, the specific volume of the refrigerant is increased. In this way, the refrigerant in a pressurized and gasified state returns to the compressor 23, so the power consumption of the compressor 23 can be reduced by the 5 Hz increase in the minimum frequency.

In this embodiment, during heating operation, for example, each part is controlled so that the evaporation temperature of the refrigerant in the outdoor heat exchanger 21 is 2°C lower than the outside air temperature. Also, the third expansion valve 33 is controlled so that the return superheat degree (Su-Th2) is 2°C.

In addition, in the heating operation, the operation switching unit 92 may learn the tendency of the time when the user operates to start the heating operation, for example, by using artificial intelligence. Then, the operation switching unit 92 may open the second expansion valve 32 and the third expansion valve 33 to start the heating operation a specified time (for example, one hour) before the start of the learned heating operation, and store heat in the first heat exchanger 62 and the second heat exchanger 63.

Figure 6 is a refrigerant system diagram that shows the air conditioner 10 during dehumidification operation of the embodiment. As shown in Figure 6, during dehumidification operation, each valve is controlled so that the refrigerant flows in the same manner as during cooling operation. However, during dehumidification operation, the three-way valve 34 is controlled so that the first bypass pipe 53 and the second bypass pipe 54 are in communication. In addition, the opening and closing valve 35 is closed. As a result, during dehumidification operation, the refrigerant flows from the discharge port 23b of the compressor 23 to the outdoor heat exchanger 21. The refrigerant that flows out of the outdoor heat exchanger 21 does not flow to the other end 53b of the first bypass pipe 53, but flows into the indoor heat exchanger 41. The refrigerant that flows out of the indoor heat exchanger 41 flows into the suction port 23a of the compressor 23 via the first bypass pipe 53 and the second bypass pipe 54. The arrows in Figure 6 show an example of the refrigerant flow during dehumidification operation.

In the first heat exchanger 62, the heat of the refrigerant flowing through the region 51d of the first pipe 51 is transferred to the refrigerant passing through the first bypass pipe 53, and the refrigerant passing through the first bypass pipe 53 is heated and gasified. At this time, the specific volume of the refrigerant is increased. In the second heat exchanger 63, the heat of the refrigerant flowing through the region 51a of the second pipe 52 is transferred to the refrigerant passing through the first bypass pipe 53, and the refrigerant passing through the first bypass pipe 53 is heated and gasified. At this time, the specific volume of the refrigerant is increased.

Here, the rated evaporation temperature of the refrigerant in the indoor heat exchanger 41 is, for example, about 13°C, and its pressure is about 1.1 MPa. In the dehumidification operation, when the blowing temperature of the indoor unit 12 is lowered to, for example, 5°C, the evaporation temperature of the low-pressure side of the refrigerant is about 3°C and its pressure is about 0.8 MPa. In other words, in the dehumidification operation, the low-pressure side of the refrigerant is lowered by 0.3 MPa. To deal with this, the workload of the compressor 23 can be increased by the amount of the reduced pressure, but this increases the power consumption of the compressor 23. Therefore, in this embodiment, as described above, during the dehumidification operation, the refrigerant is flowed through the first bypass piping 53 and heated in the first heat exchanger 62 and the second heat exchanger 63, thereby increasing the pressure of the refrigerant and removing the degree of superheat, and the refrigerant is returned to the compressor 23. As a result, there is no need to increase the frequency of the compressor 23, and energy saving of the air conditioner 10 is achieved.

In other words, in dehumidification operation, the air volume of the indoor blower fan 42 is reduced compared to cooling operation, and the amount of heat exchange in the indoor heat exchanger 41 is reduced in order to achieve dehumidification. This reduces the temperature of the indoor heat exchanger 41, making it difficult for the refrigerant returning from the indoor heat exchanger 41 to be gasified. Therefore, in this embodiment, this non-gasified refrigerant is gasified by heating it in the first heat exchanger 62 and the second heat exchanger 63.

Figure 7 is a block diagram showing an example of the hardware configuration of the control device 14 of this embodiment. The control device 14 is realized, for example, by a computer 100 having the hardware configuration shown in Figure 7.

The computer 100 has, for example, a CPU 101, a ROM 102, a RAM 103, a storage device 104, and an interface (I/F) 106. The CPU 101, the ROM 102, the RAM 103, the storage device 104, and the I/F 106 are connected by a bus.

The CPU 101 loads the programs stored in the storage device 104 into the RAM 103 and executes them, and can control each part to perform input/output and data processing. The ROM 102 stores a start program that reads the operating system startup program from the storage device 104 to the RAM 103.

The storage device 104 is, for example, a flash memory. The storage device 104 stores an operating system, application programs, and data. These programs are distributed as files in an installable or executable format recorded on a computer-readable recording medium. The programs may also be distributed by downloading them from a server.

The I/F 106 is an interface device for connecting to, for example, the temperature sensors 71A to 71J, the human presence sensor 72, the outdoor fan drive circuit 81, the indoor fan drive circuit 82, the inverter circuit 83, the four-way valve drive circuit 84, the first expansion valve drive circuit 85, the second expansion valve drive circuit 86, the third expansion valve drive circuit 87, the three-way valve drive circuit 88, and the on-off valve drive circuit 89.

The program executed by the computer 100 of this embodiment can be provided in an installable or executable format recorded on a computer-readable recording medium such as a CD-ROM, flexible disk (FD), CD-R, or DVD.

The program executed by the computer 100 of this embodiment may be stored on a computer connected to a network such as the Internet and provided by downloading it via the network. The program executed by the computer 100 of this embodiment may be provided or distributed via a network such as the Internet. The program of this embodiment may be provided by being pre-installed in the ROM 102, etc.

The program for making the computer 100 function as the control device 14 has a modular configuration including a temperature acquisition module, an operation switching module, an outdoor fan control module, an indoor fan control module, a compressor control module, and a valve control module. In the computer 100, the processor (CPU 101) reads out and executes the program from a storage medium (such as the storage device 104) as the actual hardware, and each module is loaded onto the main storage device (RAM 103). As a result, the processor (CPU 101) functions as the temperature acquisition unit 91, operation switching unit 92, outdoor fan control unit 93, indoor fan control unit 94, compressor control unit 95, and valve control unit 96 in FIG. 3. Note that the computer 100 may have some or all of the configurations of the temperature acquisition unit 91, operation switching unit 92, outdoor fan control unit 93, indoor fan control unit 94, compressor control unit 95, and valve control unit 96 realized by hardware.

As described above, in this embodiment, the air conditioner 10 includes the indoor heat exchanger 41, the outdoor heat exchanger 21, the first pipe 51, the second pipe 52, the compressor 23, the four-way valve 25, the first expansion valve 31, the first bypass pipe 53, the heat exchange unit 45, the second expansion valve 32 (first valve), the third expansion valve 33 (second valve), and the control device 14. The first pipe 51 connects the indoor heat exchanger 41 and the outdoor heat exchanger 21, and the refrigerant flows through it. The second pipe 52 connects the outdoor heat exchanger 21 and the indoor heat exchanger 41, and the refrigerant flows through it. The compressor 23 is provided in the first pipe 51 and has an intake port 23a for sucking in the refrigerant and an exhaust port 23b for discharging the refrigerant. The four-way valve 25 is provided in the first pipe 51 and can change the direction in which the refrigerant flows. The first expansion valve 31 is provided in the second pipe 52. The first bypass pipe 53 has one end 53a connected to the first pipe 51 between the indoor heat exchanger 41 and the discharge port 23b and the other end 53b connected to the second pipe 52 between the indoor heat exchanger 41 and the first expansion valve 31, and the refrigerant can flow through it. The heat exchange unit 45 exchanges heat between at least one of the first pipe 51 between the outdoor heat exchanger 21 and the suction port 23a and the second pipe 52 between the outdoor heat exchanger 21 and the first expansion valve 31 and the first bypass pipe 53. The second expansion valve 32 is provided in the first bypass pipe 53 between the one end 53a and the heat exchange unit 45 and can adjust the amount of refrigerant flowing through the first bypass pipe 53. The third expansion valve 33 is provided in the first bypass pipe 53 between the other end 53b and the heat exchanger 45, and is capable of adjusting the amount of refrigerant flowing through the first bypass pipe 53. The control device 14 controls the compressor 23, the four-way valve 25, the first expansion valve 31, the second expansion valve 32, and the third expansion valve 33.

Here, for example, when the required capacity for the air conditioner 10 is low, even if the compression capacity of the compressor 23 is set to the minimum (minimum capacity), the air conditioner 10 may exert a capacity that exceeds the required capacity. In this case, if the compressor 23 is temporarily stopped and then resumed in order to make the air conditioner 10 exert a capacity according to the required capacity, the power consumption of the air conditioner 10 is likely to increase due to backflow of the refrigerant, etc. In contrast, in this embodiment, by controlling the second expansion valve 32 and the third expansion valve 33 so that the refrigerant flows into the first bypass piping 53, a part of the refrigerant discharged from the compressor 23 (excess refrigerant) can be gasified by the heat exchanger 45 without passing through the indoor heat exchanger 41 and returned to the compressor 23. In this case, the energy of the refrigerant returning to the compressor 23 through the first bypass piping 53 is not heat exchanged in the indoor heat exchanger 41, so there is no need to stop the compressor 23. In other words, in this embodiment, continuous operation of the compressor 23 is possible. In this way, in this embodiment, since there is no need to repeatedly start and stop the compressor 23, it is possible to suppress an increase in the power consumption of the air conditioner 10, and thus to save energy in the air conditioner 10. Also, as described above, since there is no need to repeatedly start and stop the compressor 23, the temperature of the indoor heat exchanger 41 tends to be constant. Therefore, the room temperature tends to be constant.

The heat exchange unit 45 also has a first heat exchanger 62 and a second heat exchanger 63. The first heat exchanger 62 exchanges heat between the first pipe 51 between the outdoor heat exchanger 21 and the intake port 23a and the first bypass pipe 53. The second heat exchanger 63 exchanges heat between the second pipe 52 between the outdoor heat exchanger 21 and the first expansion valve 31 and the first bypass pipe 53. The second expansion valve 32 is provided in the first bypass pipe 53 between one end 53a and the first heat exchanger 62. The third expansion valve 33 is provided in the first bypass pipe 53 between the other end 53b and the second heat exchanger 63.

With this configuration, the heat exchange section 45 has a first heat exchanger 62 and a second heat exchanger 63, so the refrigerant returning to the compressor 23 via the first bypass pipe 53 can be further gasified.

The air conditioner 10 also includes, for example, a three-way valve 34, a second bypass pipe 54, and an on-off valve 35. The three-way valve 34 is provided in the first bypass pipe 53 and is capable of changing the direction in which the refrigerant flows. The second bypass pipe 54 is connected to the first pipe 51 between the compressor 23 and the four-way valve 25 and to the three-way valve 34, allowing the refrigerant to flow. The on-off valve 35 is provided in the first pipe 51 between one end 53a and the four-way valve 25.

With this configuration, during dehumidification operation, the three-way valve 34 is controlled so that the refrigerant passes from the first bypass pipe 53 to the second bypass pipe 54 and returns to the compressor 23, thereby gasifying the refrigerant in the heat exchanger 45. Therefore, during dehumidification operation, there is no need to gasify the refrigerant in the indoor heat exchanger 41, and the air volume of the indoor blower fan 42 can be reduced. This allows the temperature difference between the inside and outside of the indoor heat exchanger 41 to be increased, improving the dehumidification capacity.

The first heat exchanger 62 and the second heat exchanger 63 are heat storage materials.

With this configuration, the heat of the refrigerant can be stored in the first heat exchanger 62 and the second heat exchanger 63.

In the above embodiment, the first heat exchanger 62 and the second heat exchanger 63 are heat storage materials, but the present invention is not limited to this. For example, the first heat exchanger 62 and the second heat exchanger 63 may be double-piped.

In addition, in the above embodiment, an example in which the heat exchange unit 45 has both the first heat exchanger 62 and the second heat exchanger 63 has been shown, but this is not limited to this. For example, the heat exchange unit 45 may have only one of the first heat exchanger 62 and the second heat exchanger 63.

In addition, in the above embodiment, an example in which the second bypass pipe 54 is provided is shown, but this is not limited to this. For example, the second bypass pipe 54 does not have to be provided.

Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims.

10...air conditioner, 14...controller, 21...outdoor heat exchanger, 23...compressor, 23a...suction port, 23b...discharge port, 25...four-way valve, 31...first expansion valve, 32...second expansion valve (first valve), 33...third expansion valve (second valve), 41...indoor heat exchanger, 45...heat exchange section, 51...first pipe, 52...second pipe, 53...first bypass pipe, 53a...one end, 53b...other end, 54...second bypass pipe, 62...first heat exchanger, 63...second heat exchanger.

Claims (4)

An indoor heat exchanger;
An outdoor heat exchanger;
a first pipe connecting the indoor heat exchanger and the outdoor heat exchanger and through which a refrigerant flows;
a second pipe connecting the outdoor heat exchanger and the indoor heat exchanger and through which the refrigerant flows;
a compressor provided in the first pipe, the compressor having an intake port for sucking the refrigerant and an exhaust port for exhausting the refrigerant;
a four-way valve provided in the first pipe and capable of changing a flow direction of the refrigerant;
an expansion valve provided in the second pipe;
a first bypass pipe having one end connected to the first pipe between the indoor heat exchanger and the discharge port and the other end connected to the second pipe between the indoor heat exchanger and the expansion valve, through which the refrigerant can flow;
a heat exchange unit that performs heat exchange between at least one of the first pipe between the outdoor heat exchanger and the suction port and the second pipe between the outdoor heat exchanger and the expansion valve, and the first bypass pipe;
a first valve provided in the first bypass pipe between the one end and the heat exchange unit and capable of adjusting an amount of the refrigerant flowing through the first bypass pipe;
a second valve provided in the first bypass pipe between the other end and the heat exchanger and capable of adjusting an amount of the refrigerant flowing through the first bypass pipe;
a control device that controls the four-way valve, the expansion valve, the first valve, and the second valve;
Equipped with
The heat exchange unit is
a first heat exchanger that exchanges heat between the first pipe between the outdoor heat exchanger and the suction port and the first bypass pipe;
a second heat exchanger that performs heat exchange between the second pipe between the outdoor heat exchanger and the expansion valve and the first bypass pipe;
having
the first valve is provided in the first bypass pipe between the one end and the first heat exchanger,
The second valve is provided in the first bypass pipe between the other end and the second heat exchanger.
Air conditioner. An indoor heat exchanger;
An outdoor heat exchanger;
a first pipe connecting the indoor heat exchanger and the outdoor heat exchanger and through which a refrigerant flows;
a second pipe connecting the outdoor heat exchanger and the indoor heat exchanger and through which the refrigerant flows;
a compressor provided in the first pipe, the compressor having an intake port for sucking the refrigerant and an exhaust port for exhausting the refrigerant;
a four-way valve provided in the first pipe and capable of changing a flow direction of the refrigerant;
an expansion valve provided in the second pipe;
a first bypass pipe having one end connected to the first pipe between the indoor heat exchanger and the discharge port and the other end connected to the second pipe between the indoor heat exchanger and the expansion valve, through which the refrigerant can flow;
a heat exchange unit that performs heat exchange between at least one of the first pipe between the outdoor heat exchanger and the suction port and the second pipe between the outdoor heat exchanger and the expansion valve, and the first bypass pipe;
a first valve provided in the first bypass pipe between the one end and the heat exchange unit and capable of adjusting an amount of the refrigerant flowing through the first bypass pipe;
a second valve provided in the first bypass pipe between the other end and the heat exchanger and capable of adjusting an amount of the refrigerant flowing through the first bypass pipe;
a control device that controls the four-way valve, the expansion valve, the first valve, and the second valve;
a three-way valve provided in the first bypass pipe and capable of changing a direction in which the refrigerant flows;
a second bypass pipe connected to the first pipe between the compressor and the four-way valve and to the three-way valve, through which the refrigerant can flow;
an on-off valve provided in the first pipe between the one end and the four-way valve;
An air conditioner equipped with: a three-way valve provided in the first bypass pipe and capable of changing a direction in which the refrigerant flows;
a second bypass pipe connected to the first pipe between the compressor and the four-way valve and to the three-way valve, through which the refrigerant can flow;
an on-off valve provided in the first pipe between the one end and the four-way valve;
The air conditioner according to claim 1 . The air conditioner according to claim 1 or 3 , wherein the first heat exchanger and the second heat exchanger are made of a heat storage material.

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