Air conditioning device and method for controlling air conditioning device

Abstract

The present invention provides an air conditioning device (100) comprising: a compressor (10); an indoor heat exchanger (20); a four-way valve (40); an outdoor heat exchanger (30) that includes a first outdoor heat exchange unit (31), a second outdoor heat exchange unit (32), and a third outdoor heat exchange unit (33); an operation mode switching unit (60) that, in a heating operation state, switches between a first defrosting operation mode in which a part of a coolant discharged from the compressor (10) to the four-way valve (40) is guided to the first outdoor heat exchange unit (31), a second defrosting operation mode in which a part of the coolant discharged from the compressor (10) to the four-way valve (40) is guided to the second outdoor heat exchange unit (32), and a normal operation mode in which the coolant that has passed through the third outdoor heat exchange unit (33) is guided to both the first outdoor heat exchange unit (31) and the second outdoor heat exchange unit (32); and a control unit (70) that controls the four-way valve (40) and the operation mode switching unit (60).

Description

Air conditioner and method for controlling air conditioner

[0001] The present disclosure relates to an air conditioner and a method for controlling an air conditioner.

[0002] Conventionally, there has been known an air conditioning system in which the outdoor heat exchanger is divided into a first outdoor heat exchanger and a second outdoor heat exchanger connected in parallel to the refrigerant circulation flow path, and when frost forms on the outdoor heat exchanger, either the first outdoor heat exchanger or the second outdoor heat exchanger is selected, and the refrigerant discharged from the compressor is supplied to the selected outdoor heat exchanger to perform defrosting operation (see, for example, Patent Document 1).

[0003] The air conditioning apparatus disclosed in Patent Document 1 can remove frost that has adhered to one of the outdoor heat exchangers selected as the target for defrost operation, and can maintain heating operation during defrost operation by causing the other outdoor heat exchanger that is not selected as the target for defrost operation to function as an evaporator.

[0004] Patent No. 6021940

[0005] However, in the air conditioning system disclosed in Patent Document 1, if the outdoor heat exchanger is divided into two, a first outdoor heat exchanger and a second outdoor heat exchanger, so that they have the same heat exchange capacity, half of the outdoor heat exchanger is subject to defrosting operation, and the time required to remove frost cannot be sufficiently reduced. Furthermore, Patent Document 1 indicates that the outdoor heat exchanger can be divided into any number greater than two, but the number of divisions requires the installation of additional solenoid valves and flow control devices, which increases manufacturing costs.

[0006] The present disclosure has been made in consideration of the above circumstances, and aims to provide an air conditioning apparatus and a control method for an air conditioning apparatus that can perform defrost operation that shortens the time required to defrost the outdoor heat exchanger without stopping heating by the indoor heat exchanger and without increasing manufacturing costs.

[0007] In order to solve the above problems, the air conditioner of the present disclosure employs the following means: an air conditioner according to one aspect of the present disclosure includes a compressor that compresses and discharges a refrigerant, an indoor heat exchanger, an outdoor heat exchanger having a first outdoor heat exchange portion, a second outdoor heat exchange portion, and a third outdoor heat exchange portion, a cooling / heating switching portion that switches between a heating operation state in which the refrigerant discharged from the compressor is supplied to the indoor heat exchanger and a cooling operation state in which the refrigerant discharged from the compressor is supplied to the outdoor heat exchanger, a refrigerant piping that circulates the refrigerant between the operation mode switching portion and the third outdoor heat exchange portion via the indoor heat exchanger, a first expansion valve that is arranged in the refrigerant piping between the indoor heat exchanger and the outdoor heat exchanger, and a first expansion valve that, in the heating operation state, guides a portion of the refrigerant discharged from the compressor to the cooling / heating switching portion to the first outdoor heat exchange portion and cools the refrigerant that has passed through the first outdoor heat exchange portion and the third outdoor heat exchange portion. and a control unit for controlling the cooling / heating switching unit and the operation mode switching unit.

[0008] a cooling / heating switching unit configured to switch between a heating operation state in which the refrigerant discharged from the compressor is supplied to the indoor heat exchanger and a cooling operation state in which the refrigerant discharged from the compressor is supplied to the outdoor heat exchanger; a refrigerant piping configured to circulate the refrigerant between the operation mode switching unit and the third outdoor heat exchanger via the indoor heat exchanger; a first expansion valve configured to be disposed in the refrigerant piping between the indoor heat exchanger and the outdoor heat exchanger; a first defrost operation mode in which, in the heating operation state, a portion of the refrigerant discharged from the compressor to the cooling / heating switching unit is guided to the first outdoor heat exchanger; and an operation mode switching unit that switches between a second defrost operation mode in which a portion of the refrigerant is guided to the second outdoor heat exchange unit, and a normal operation mode in which the refrigerant that has passed through the third outdoor heat exchange unit is guided to both the first outdoor heat exchange unit and the second outdoor heat exchange unit, and the operation mode switching unit is provided with a control process that controls the operation mode switching unit so that, in the first defrost operation mode, the refrigerant that has passed through the first outdoor heat exchange unit and the refrigerant that has passed through the third outdoor heat exchange unit are merged and the refrigerant is guided to the compressor via the second outdoor heat exchange unit, in the second defrost operation mode, the refrigerant that has passed through the second outdoor heat exchange unit and the refrigerant that has passed through the third outdoor heat exchange unit are merged and the refrigerant is guided to the compressor via the first outdoor heat exchange unit, and in the normal operation mode, the refrigerant that has passed through the first outdoor heat exchange unit and the refrigerant that has passed through the second outdoor heat exchange unit are merged and the refrigerant is guided to the compressor via the first outdoor heat exchange unit.

[0009] According to the present disclosure, it is possible to provide an air conditioning apparatus and a control method for an air conditioning apparatus that can perform defrost operation that shortens the time required to defrost the outdoor heat exchanger without stopping heating by the indoor heat exchanger and without increasing manufacturing costs.

[0010] 1 is a diagram showing a refrigerant circuit of an air conditioning apparatus according to an embodiment of the present disclosure, illustrating a state in which a normal operation mode is executed in a heating operation state; FIG. 2 is a diagram showing a refrigerant circuit of an air conditioning apparatus according to an embodiment of the present disclosure, illustrating a state in which a first defrost operation mode is executed in a heating operation state; FIG. 3 is a diagram showing a refrigerant circuit of an air conditioning apparatus according to an embodiment of the present disclosure, illustrating a state in which a second defrost operation mode is executed in a heating operation state; FIG. 4 is a diagram showing a refrigerant circuit of an air conditioning apparatus according to an embodiment of the present disclosure, illustrating a cooling operation state; FIG. 5 is a flowchart showing a control method for an air conditioning apparatus according to an embodiment of the present disclosure; FIG. 6 is a diagram showing a first modified example of an outdoor heat exchanger; FIG. 7 is a diagram showing a second modified example of an outdoor heat exchanger;

[0011] An air conditioning apparatus 100 according to an embodiment of the present disclosure will now be described with reference to the drawings. Fig. 1 is a diagram showing a refrigerant circuit of the air conditioning apparatus 100 according to an embodiment of the present disclosure, illustrating a state in which a normal operation mode is executed in a heating operation state. Fig. 2 is a diagram showing a refrigerant circuit of the air conditioning apparatus 100 according to an embodiment of the present disclosure, illustrating a state in which a first defrost operation mode is executed in a heating operation state. Fig. 3 is a diagram showing a refrigerant circuit of the air conditioning apparatus according to an embodiment of the present disclosure, illustrating a state in which a second defrost operation mode is executed in a heating operation state.

[0012] 1 to 3, the air conditioning apparatus 100 of this embodiment includes a compressor 10, an indoor heat exchanger 20, an outdoor heat exchanger 30, a four-way valve (cooling / heating switching unit) 40, a refrigerant pipe L1, a first expansion valve 50, an operation mode switching unit 60, and a control unit 70. In Figures 1 to 3, the portions through which the refrigerant R flows are indicated by solid lines, and the portions through which the refrigerant R does not flow are indicated by dotted lines.

[0013] The compressor 10 is a device that compresses the refrigerant R and discharges the high-temperature, high-pressure refrigerant R toward the four-way valve 40. As the compressor 10, for example, an inverter-driven electric compressor is used.

[0014] The indoor heat exchanger 20 is installed in a room to be cooled or heated. In a heating operation state, the indoor heat exchanger 20 functions as a condenser when high-temperature, high-pressure refrigerant R discharged from the compressor 10 is supplied via the four-way valve 40, and heats the room by heating the air with the condensation heat released when the refrigerant R condenses. In a cooling operation state, the indoor heat exchanger 20 functions as an evaporator when the indoor heat exchanger 20 is supplied with refrigerant R decompressed by the first expansion valve 50, and cools the room by cooling the air with the heat of vaporization released when the refrigerant R evaporates.

[0015] The outdoor heat exchanger 30 is a device installed outdoors, and in a heating operation state, when refrigerant R decompressed by the first expansion valve 50 is supplied, the outdoor heat exchanger 30 functions as an evaporator, imparting heat from outside air to the refrigerant R to vaporize the low-temperature, low-pressure refrigerant R. The refrigerant R vaporized in the outdoor heat exchanger 30 is supplied to the compressor 10 via the operation mode switching unit 60. In addition, in a cooling operation state, when high-temperature, high-pressure refrigerant R discharged from the compressor 10 is supplied via the operation mode switching unit 60, the outdoor heat exchanger 30 functions as a condenser, releasing heat from the refrigerant R to the outside air, thereby condensing the high-temperature, high-pressure gas-phase refrigerant R and changing it to a liquid phase.

[0016] The outdoor heat exchanger 30 has a first outdoor heat exchange section 31, a second outdoor heat exchange section 32, and a third outdoor heat exchange section 33. In the vertical direction, the first outdoor heat exchange section 31 is disposed above the second outdoor heat exchange section 32. When frost formed on the first outdoor heat exchange section 31 is defrosted, water generated in the first outdoor heat exchange section 31 drips toward the second outdoor heat exchange section 32 disposed below. Furthermore, in the vertical direction, the third outdoor heat exchange section 33 is disposed below the second outdoor heat exchange section 32. When frost formed on the second outdoor heat exchange section 32 is defrosted, water generated in the second outdoor heat exchange section 32 drips toward the third outdoor heat exchange section 33 disposed below.

[0017] The four-way valve 40 is a device that switches between a heating operation state in which the refrigerant R discharged from the compressor 10 is supplied to the indoor heat exchanger 20 and a cooling operation state in which the refrigerant R discharged from the compressor 10 is supplied to the outdoor heat exchanger 30. In the cooling operation state, the four-way valve 40 guides the refrigerant R supplied from the indoor heat exchanger 20 to the compressor 10. The control unit 70 controls the four-way valve 40 to switch between the heating operation state and the cooling operation state.

[0018] The refrigerant pipe L1 is a pipe that circulates the refrigerant R between the four-way valve 40 and the third outdoor heat exchange unit 33 via the indoor heat exchanger 20. In the heating operation state, the refrigerant pipe L1 supplies the refrigerant R from the four-way valve 40 to the third outdoor heat exchange unit 33 via the indoor heat exchanger 20 and the first expansion valve 50. In the cooling operation state, the refrigerant pipe L1 supplies the refrigerant R from the third outdoor heat exchange unit 33 to the four-way valve 40 via the first expansion valve 50 and the indoor heat exchanger 20.

[0019] The first expansion valve 50 is a device disposed in the refrigerant pipe L1 between the indoor heat exchanger 20 and the outdoor heat exchanger 30. In the heating operation state, the first expansion valve 50 reduces the pressure of the refrigerant R supplied from the indoor heat exchanger 20 and supplies it to the third outdoor heat exchange section 33. In the cooling operation state, the first expansion valve 50 reduces the pressure of the refrigerant R supplied from the third outdoor heat exchange section 33 and supplies it to the indoor heat exchanger 20.

[0020] The operation mode switching unit 60 is a device that switches between a first defrost operation mode, a second defrost operation mode, and a normal operation mode during heating operation. The first defrost operation mode is an operation mode in which, when frost formation on the outdoor heat exchanger 30 is detected, a portion of the refrigerant R discharged from the compressor 10 to the four-way valve 40 is guided to the first outdoor heat exchange unit 31 to defrost the first outdoor heat exchange unit 31. The second defrost operation mode is an operation mode in which, when frost formation on the outdoor heat exchanger 30 is detected, a portion of the refrigerant R discharged from the compressor 10 to the four-way valve 40 is guided to the second outdoor heat exchange unit 32 to defrost the second outdoor heat exchange unit 32.

[0021] The normal operation mode is an operation mode in which, when frost formation is not detected in the outdoor heat exchanger 30, the refrigerant R that has passed through the third outdoor heat exchange section 33 is guided to both the first outdoor heat exchange section 31 and the second outdoor heat exchange section 32 to vaporize the refrigerant R through heat exchange with outdoor air. In the cooling operation state, the operation mode switching section 60 guides the refrigerant R discharged from the compressor 10 to both the first outdoor heat exchange section 31 and the second outdoor heat exchange section 32 to condense the refrigerant R through heat exchange with outdoor air. The liquid-phase refrigerant R that has passed through both the first outdoor heat exchange section 31 and the second outdoor heat exchange section 32 is subcooled when passing through the third outdoor heat exchange section 33 and is guided to the first expansion valve 50.

[0022] The operation mode switching unit 60 has a check valve 61, a second expansion valve 62, a third expansion valve 63, a fourth expansion valve 64, a three-way valve 65, and a three-way valve 66. Each part of the operation mode switching unit 60 is controlled by a control unit 70.

[0023] The second expansion valve 62 is a device that adjusts the flow rate of the refrigerant R that is discharged from the compressor 10 to the four-way valve 40 and guided to the first outdoor heat exchange unit 31 and / or the second outdoor heat exchange unit 32. The opening degree of the second expansion valve 62 is adjusted by the control unit 70 so that the temperature of the refrigerant R that has passed through the first outdoor heat exchange unit 31 is 10°C or higher in the first defrost operation mode, and so that the temperature of the refrigerant R that has passed through the second outdoor heat exchange unit 32 is 10°C or higher in the second defrost operation mode.

[0024] 1 , when the normal operation mode is executed in the heating operation state, the control unit 70 controls the operation mode switching unit 60 to close the second expansion valve 62 and guide all of the refrigerant R discharged from the compressor 10 to the four-way valve 40 from the four-way valve 40 to the indoor heat exchanger 20. The control unit 70 also controls the three-way valve 65 to open the third expansion valve 63 and guide the refrigerant R that has passed through the third outdoor heat exchange unit 33 and the first outdoor heat exchange unit 31 through the three-way valve 65 to the compressor 10. The control unit 70 also controls the four-way valve 66 to open the fourth expansion valve 64 and guide the refrigerant R that has passed through the third outdoor heat exchange unit 33 and the second outdoor heat exchange unit 32 through the three-way valve 66 to the compressor 10.

[0025] 2 , when the first defrost operation mode is executed in the heating operation state, the control unit 70 controls the operation mode switching unit 60 to open the second expansion valve 62 and cause a portion of the refrigerant R discharged from the compressor 10 to the four-way valve 40 to pass through the second expansion valve 62. The control unit 70 also controls the three-way valves 65 and 66 to cause the refrigerant R that has passed through the second expansion valve 62 to be guided to the first outdoor heat exchange unit 31 via the three-way valve 65.

[0026] The control unit 70 also opens the fourth expansion valve 64, merges the refrigerant R that has passed through the third expansion valve 63 and the refrigerant R that has passed through the third outdoor heat exchange unit 33, and passes the merged refrigerant R through the second outdoor heat exchange unit 32. The control unit 70 also controls the three-way valve 66 so that the refrigerant R that has passed through the second outdoor heat exchange unit 32 is guided to the compressor 10.

[0027] 3 , when the second defrost operation mode is executed in the heating operation state, the control unit 70 controls the operation mode switching unit 60 to open the second expansion valve 62 and allow a portion of the refrigerant R discharged from the compressor 10 to the four-way valve 40 to pass through the second expansion valve 62. The control unit 70 also controls the three-way valves 65 and 66 to allow the refrigerant R that has passed through the second expansion valve 62 to be guided to the second outdoor heat exchange unit 32 via the three-way valve 66.

[0028] The control unit 70 also opens the third expansion valve 63 and the fourth expansion valve 64, merges the refrigerant R that has passed through the fourth expansion valve 64 with the refrigerant R that has passed through the third outdoor heat exchange unit 33, and passes the merged refrigerant R through the first outdoor heat exchange unit 31. The control unit 70 also controls the three-way valve 65 so that the refrigerant R that has passed through the first outdoor heat exchange unit 31 is guided to the compressor 10.

[0029] 4 , in the cooling operation state, the control unit 70 closes the second expansion valve 62 and controls the operation mode switching unit 60 so that all of the refrigerant R discharged from the compressor 10 to the four-way valve 40 is guided from the four-way valve 40 to the check valve 61. The control unit 70 also controls the three-way valves 65 and 66 so that the refrigerant R that has passed through the check valve 61 is guided to both the first outdoor heat exchange unit 31 and the second outdoor heat exchange unit 32. The control unit 70 also controls the third expansion valve 63 and the fourth expansion valve 64 to open so that the refrigerant R that has passed through the first outdoor heat exchange unit 31 and the refrigerant R that has passed through the second outdoor heat exchange unit 32 are joined together and guided from the third outdoor heat exchange unit 33 to the refrigerant pipe L1.

[0030] Next, a control method for the air conditioning apparatus 100 of this embodiment will be described with reference to Fig. 5. Fig. 5 is a flowchart showing a control method for the air conditioning apparatus 100 of this embodiment.

[0031] In step S101, the control unit 70 determines whether or not to perform the heating operation. If YES, the process proceeds to step S102, and if NO, the process proceeds to step S103.

[0032] In step S102, the control unit 70 controls the four-way valve 40 so that the refrigerant R discharged from the compressor 10 to the four-way valve 40 is supplied to the indoor heat exchanger 20, thereby setting up the heating operation state.

[0033] In step S103, the control unit 70 controls the four-way valve 40 so that the refrigerant R discharged from the compressor 10 to the four-way valve 40 is supplied to the outdoor heat exchanger 30, thereby setting the cooling operation state.

[0034] In step S104, the control unit 70 determines whether frost has formed on the outdoor heat exchanger 30. If the determination is YES, the process proceeds to step S105, and if the determination is NO, the process proceeds to step S107. The control unit 70 determines whether frost has formed on the outdoor heat exchanger 30 based on a signal from a frost detection sensor (not shown) installed in the outdoor heat exchanger 30, for example.

[0035] In step S105, the control unit 70 controls the operation mode switching unit 60 to execute the first defrost operation mode.

[0036] In step S106, the control unit 70 controls the operation mode switching unit 60 to execute the second defrost operation mode. After executing step S106, the control unit 70 performs the determination in step S104 again.

[0037] In step S107, the control unit 70 controls the operation mode switching unit 60 to execute the normal operation mode.

[0038] In step S108, the control unit 70 determines whether or not to terminate the operation of the air conditioning apparatus 100. If YES, the process proceeds to step S109; if NO, the control unit 70 executes step S101 again.

[0039] In step S109, the control unit 70 stops the operation of the air conditioning apparatus 100 to put it into a stopped state, and ends the processing of this flowchart.

[0040] In the process shown in the flowchart above, the control unit 70 controls the operation mode switching unit 60 to switch to the normal operation mode after executing the second defrost operation mode following the first defrost operation mode. This is because if the normal operation mode is switched to without executing the second defrost operation mode following the first defrost operation mode, water dripping from the first outdoor heat exchange unit 31 onto the second outdoor heat exchange unit 32 below will increase frost formation on the second outdoor heat exchange unit 32.

[0041] In the above description, the outdoor heat exchanger 30 is described as being arranged in the order of the first outdoor heat exchange section 31, the second outdoor heat exchange section 32, and the third outdoor heat exchange section 33 from top to bottom in the vertical direction, but other configurations are also possible. For example, as shown in Fig. 6 , a first modified example may be used in which the second outdoor heat exchange section 32 and the third outdoor heat exchange section 33 are arranged at positions that overlap in the vertical direction VD.

[0042] Fig. 6 is a diagram showing a first modified example of an outdoor heat exchanger. As shown in Fig. 6, an outdoor heat exchanger 30A of the first modified example has a first outdoor heat exchange section 31, a second outdoor heat exchange section 32, a third outdoor heat exchange section 33, and a fan 34. By rotating the fan 34, the outdoor heat exchanger 30A causes outdoor air to flow along the flow direction FD and pass through the first outdoor heat exchange section 31, the second outdoor heat exchange section 32, and the third outdoor heat exchange section 33.

[0043] In the outdoor heat exchanger 30A shown in Fig. 6, the second outdoor heat exchange section 32 and the third outdoor heat exchange section 33 are arranged in positions that overlap in the vertical direction VD. The third outdoor heat exchange section 33 is arranged upstream of the second outdoor heat exchange section 32 in the outdoor air flow direction FD. According to the outdoor heat exchanger 30A shown in Fig. 6, in a heating operation state, when the temperature of the refrigerant R circulating through the third outdoor heat exchange section 33 is higher than the temperature of the outdoor air, the outdoor air heated by heat exchange with the refrigerant R in the third outdoor heat exchange section 33 is guided to the second outdoor heat exchange section 32, thereby making it difficult for moisture contained in the outdoor air passing through the second outdoor heat exchange section 32 to condense.

[0044] In the outdoor heat exchanger 30A of the first modified example shown in Fig. 6, the second outdoor heat exchange section 32 and the third outdoor heat exchange section 33 are arranged in positions that do not overlap along the outdoor air flow direction FD, but other configurations are also possible. For example, as in the second modified example shown in Fig. 7, the second outdoor heat exchange section 32 and the third outdoor heat exchange section 33 may be arranged in positions that overlap along the outdoor air flow direction FD. Fig. 7 is a diagram showing a second modified example of the outdoor heat exchanger. According to the outdoor heat exchanger 30B of the second modified example, it is possible to reduce the size of the outdoor heat exchanger 30B in the flow direction FD while making it difficult for moisture contained in the outdoor air passing through the second outdoor heat exchange section 32 to condense.

[0045] The air conditioning apparatus 100 of the present embodiment described above provides the following actions and effects.

[0046] According to the air conditioning apparatus 100 of this embodiment, the outdoor heat exchanger 30 is divided into a first outdoor heat exchange section 31, a second outdoor heat exchange section 32, and a third outdoor heat exchange section 33, and in the heating operation state, a first defrost operation mode, a second defrost operation mode, and a normal operation mode are switched and executed. In the heating operation state, the room is heated by the heat of condensation of the refrigerant R supplied from the compressor 10 to the indoor heat exchanger 20 via the four-way valve 40, and the refrigerant R that passes through the indoor heat exchanger 20 and is decompressed by the first expansion valve 50 is guided to the third outdoor heat exchange section 33 via the refrigerant piping L1.

[0047] According to the air conditioning apparatus 100 of this embodiment, in the heating operation state, regardless of whether the operation mode switching unit 60 switches between the first defrost operation mode, the second defrost operation mode, or the normal operation mode, the third outdoor heat exchange unit 33 functions as an evaporator and is not a destination of refrigerant R supplied from the compressor 10 without passing through the indoor heat exchanger 20. The third outdoor heat exchange unit 33, which is part of the outdoor heat exchanger 30, is excluded from the destination of refrigerant R in the first defrost operation mode and the second defrost operation mode. For example, if the heat exchange capacities of the first outdoor heat exchange unit 31 and the second outdoor heat exchange unit 32 are set to be equal, the destination of refrigerant R in the defrost operation mode can be set to less than half of the entire outdoor heat exchanger 30. This allows the temperature of refrigerant R used for defrosting at the destination of refrigerant R to be maintained high, thereby shortening the time required for defrosting.

[0048] Furthermore, according to the air conditioning apparatus 100 of this embodiment, in heating operation, the third outdoor heat exchanger 33 functions as an evaporator, so there is no need to install new piping, valves, or the like to supply refrigerant from the compressor 10 to the third outdoor heat exchanger 33 without passing through the indoor heat exchanger 20. Therefore, a defrosting operation can be performed that shortens the time required to defrost the outdoor heat exchanger 30 without increasing manufacturing costs and without stopping heating by the indoor heat exchanger 20.

[0049] According to the air conditioning apparatus 100 of this embodiment, the normal operation mode is switched to after the second defrost operation mode is executed following the first defrost operation mode, and therefore the normal operation mode is not switched to without executing the second defrost operation mode following the first defrost operation mode. This makes it possible to appropriately prevent a situation in which water dripping from the first outdoor heat exchange unit 31 to the second outdoor heat exchange unit 32 below in the first defrost operation mode increases frost formation on the second outdoor heat exchange unit 32 and the normal operation mode is switched to.

[0050] According to the air conditioning apparatus 100 of this embodiment, in the heating operation state, the third outdoor heat exchange unit 33 is disposed upstream of the first outdoor heat exchange unit 31 and the second outdoor heat exchange unit 32 in the flow direction of the refrigerant R, and the temperature of the flowing refrigerant R is highest. Therefore, by disposing the third outdoor heat exchange unit 33 below the second outdoor heat exchange unit 32, it is possible to suppress frost formation on the outdoor heat exchanger 30. The reason why the temperature of the refrigerant R flowing through the third outdoor heat exchange unit 33 is higher than the temperature of the refrigerant R flowing through the first outdoor heat exchange unit 31 and the second outdoor heat exchange unit 32 is that, due to pressure loss, the pressure of the refrigerant R in a gas-liquid two-phase region decreases as it advances downstream, and the temperature of the refrigerant R decreases.

[0051] According to the air conditioning device 100 of this embodiment, by setting the temperature of the refrigerant R that has passed through the first outdoor heat exchange unit 31 to 10°C or higher in the first defrost operation mode, and by setting the temperature of the refrigerant R that has passed through the second outdoor heat exchange unit 32 to 10°C or higher in the second defrost operation mode, it is possible to maintain appropriate defrosting performance and shorten the time required for defrosting.

[0052] The air conditioning apparatus (100) described in each of the above-described embodiments can be understood, for example, as follows.

[0053] An air conditioning apparatus according to a first aspect of the present disclosure includes a compressor (10) that compresses and discharges a refrigerant, an indoor heat exchanger (20), an outdoor heat exchanger (30) having a first outdoor heat exchange section (31), a second outdoor heat exchange section (32), and a third outdoor heat exchange section (33), a cooling / heating switching section (40) that switches between a heating operation state in which the refrigerant discharged from the compressor is supplied to the indoor heat exchanger and a cooling operation state in which the refrigerant discharged from the compressor is supplied to the outdoor heat exchanger, a refrigerant pipe (L1) that circulates the refrigerant between the cooling / heating switching section and the third outdoor heat exchange section via the indoor heat exchanger, a first expansion valve (50) that is arranged in the refrigerant pipe between the indoor heat exchanger and the outdoor heat exchanger, and a second expansion valve (50) that, in the heating operation state, guides a portion of the refrigerant discharged from the compressor to the cooling / heating switching section to the first outdoor heat exchange section and cools the refrigerant that has passed through the first outdoor heat exchange section. a first defrosting operation mode in which a part of the refrigerant discharged from the compressor to the cooling / heating switching unit is guided to the second outdoor heat exchange unit, and the refrigerant that has passed through the second outdoor heat exchange unit and the refrigerant that has passed through the third outdoor heat exchange unit are joined together, and the refrigerant is guided to the compressor via the first outdoor heat exchange unit; and a normal operation mode in which the refrigerant that has passed through the third outdoor heat exchange unit is guided to both the first outdoor heat exchange unit and the second outdoor heat exchange unit, and the refrigerant that has passed through the first outdoor heat exchange unit and the refrigerant that has passed through the second outdoor heat exchange unit are joined together, and the normal operation mode is guided to the compressor; and a control unit (70) that controls the cooling / heating switching unit and the operation mode switching unit.

[0054] According to the air conditioning apparatus of the first aspect of the present disclosure, the outdoor heat exchanger is divided into a first outdoor heat exchange section, a second outdoor heat exchange section, and a third outdoor heat exchange section, and in a heating operation state, a first defrost operation mode, a second defrost operation mode, and a normal operation mode are switched between. In the heating operation state, the room is heated by the heat of condensation of the refrigerant supplied from the compressor to the indoor heat exchanger via the cooling / heating switching section, and the refrigerant that has passed through the indoor heat exchanger and has been decompressed by the first expansion valve is guided to the third outdoor heat exchange section via the refrigerant piping.

[0055] According to the air conditioning apparatus of the first aspect of the present disclosure, in the heating operation state, regardless of whether the operation mode switching unit switches between the first defrost operation mode, the second defrost operation mode, and the normal operation mode, the third outdoor heat exchange unit functions as an evaporator and is not a destination of refrigerant supplied from the compressor without passing through the indoor heat exchanger. The third outdoor heat exchange unit, which is part of the outdoor heat exchanger, is excluded from the destination of refrigerant in the first defrost operation mode and the second defrost operation mode. For example, if the heat exchange capacities of the first outdoor heat exchange unit and the second outdoor heat exchange unit are set to be equal, the destination of refrigerant in the defrost operation mode can be less than half of the entire outdoor heat exchanger. This allows the temperature of the refrigerant used for defrosting at the destination of the refrigerant to be maintained high, thereby shortening the time required for defrosting.

[0056] Furthermore, according to the air conditioning apparatus according to the first aspect of the present disclosure, in heating operation, the third outdoor heat exchange unit functions as an evaporator, so there is no need to install new piping, valves, etc. for supplying refrigerant from the compressor to the third outdoor heat exchange unit without passing through the indoor heat exchanger. As a result, it is possible to perform a defrosting operation that shortens the time required to defrost the outdoor heat exchanger without increasing manufacturing costs and without stopping heating by the indoor heat exchanger.

[0057] An air conditioning apparatus according to a second aspect of the present disclosure is the same as the first aspect, but further includes the following configuration: In other words, in the vertical direction (VD), the first outdoor heat exchange unit is disposed above the second outdoor heat exchange unit, and the control unit controls the operation mode switching unit to switch to the normal operation mode after executing the second defrost operation mode subsequent to the first defrost operation mode.

[0058] According to the air conditioning apparatus of the second aspect of the present disclosure, the normal operation mode is switched to after the second defrost operation mode is executed following the first defrost operation mode, and therefore the normal operation mode is not switched to without the second defrost operation mode being executed following the first defrost operation mode. This appropriately prevents the normal operation mode from being switched to while water dripping from the first outdoor heat exchange unit onto the second outdoor heat exchange unit below in the first defrost operation mode increases frost formation on the second outdoor heat exchange unit. The temperature of the refrigerant flowing through the third outdoor heat exchange unit is higher than the temperatures of the refrigerant flowing through the first outdoor heat exchange unit and the second outdoor heat exchange unit because, due to pressure loss, the pressure of the refrigerant in a gas-liquid two-phase region decreases downstream, causing the refrigerant temperature to decrease.

[0059] The air conditioning apparatus according to a third aspect of the present disclosure is the second aspect, further including the following configuration: That is, in the vertical direction, the third outdoor heat exchange unit is disposed below the second outdoor heat exchange unit.

[0060] According to the air conditioning apparatus of the third aspect of the present disclosure, in heating operation, the third outdoor heat exchange unit is disposed upstream of the first outdoor heat exchange unit and the second outdoor heat exchange unit in the refrigerant flow direction, and the temperature of the flowing refrigerant is highest. Therefore, by disposing the third outdoor heat exchange unit below the second outdoor heat exchange unit, it is possible to suppress frost formation on the outdoor heat exchanger.

[0061] An air conditioning apparatus according to a fourth aspect of the present disclosure is the air conditioning apparatus of any one of the first to third aspects, further including the following configuration: That is, the operation mode switching unit has a second expansion valve (62) that adjusts the flow rate of the refrigerant that is discharged from the compressor to the cooling / heating switching unit and guided to the first outdoor heat exchange unit or the second outdoor heat exchange unit, and the control unit controls the second expansion valve so that the temperature of the refrigerant that has passed through the first outdoor heat exchange unit is 10°C or higher in the first defrost operation mode, and so that the temperature of the refrigerant that has passed through the second outdoor heat exchange unit is 10°C or higher in the second defrost operation mode.

[0062] According to the air conditioning apparatus of the fourth aspect of the present disclosure, by setting the temperature of the refrigerant that has passed through the first outdoor heat exchange unit to 10°C or higher in the first defrost operation mode, and by setting the temperature of the refrigerant that has passed through the second outdoor heat exchange unit to 10°C or higher in the second defrost operation mode, it is possible to maintain appropriate defrosting performance and shorten the time required for defrosting.

[0063] In a control method for an air conditioner according to a fifth aspect of the present disclosure, the air conditioner includes: a compressor that compresses and discharges a refrigerant; an indoor heat exchanger; an outdoor heat exchanger having a first outdoor heat exchange unit, a second outdoor heat exchange unit, and a third outdoor heat exchange unit; a cooling / heating switching unit that switches between a heating operation state in which the refrigerant discharged from the compressor is supplied to the indoor heat exchanger and a cooling operation state in which the refrigerant discharged from the compressor is supplied to the outdoor heat exchanger; a refrigerant piping that circulates the refrigerant between the cooling / heating switching unit and the third outdoor heat exchange unit via the indoor heat exchanger; a first expansion valve that is disposed in the refrigerant piping between the indoor heat exchanger and the outdoor heat exchanger; a first defrost operation mode in which, in the heating operation state, a portion of the refrigerant discharged from the compressor to the cooling / heating switching unit is guided to the first outdoor heat exchange unit; and an operation mode switching unit that switches between a second defrost operation mode in which the refrigerant that has passed through the first outdoor heat exchange unit is guided to an outdoor heat exchange unit, and a normal operation mode in which the refrigerant that has passed through the third outdoor heat exchange unit is guided to both the first outdoor heat exchange unit and the second outdoor heat exchange unit, and the operation mode switching unit is configured to control the operation mode switching unit so that, in the first defrost operation mode, the refrigerant that has passed through the first outdoor heat exchange unit and the refrigerant that has passed through the third outdoor heat exchange unit are merged and the refrigerant is guided to the compressor via the second outdoor heat exchange unit, in the second defrost operation mode, the refrigerant that has passed through the second outdoor heat exchange unit and the refrigerant that has passed through the third outdoor heat exchange unit are merged and the refrigerant is guided to the compressor via the first outdoor heat exchange unit, and in the normal operation mode, the operation mode switching unit is configured to control the operation mode switching unit so that, in the first defrost operation mode, the refrigerant that has passed through the second outdoor heat exchange unit and the refrigerant that has passed through the third outdoor heat exchange unit are merged and the refrigerant is guided to the compressor via the first outdoor heat exchange unit, and

[0064] According to a control method for an air conditioner according to a fifth aspect of the present disclosure, the outdoor heat exchanger is divided into a first outdoor heat exchange unit, a second outdoor heat exchange unit, and a third outdoor heat exchange unit, and in a heating operation state, a first defrost operation mode, a second defrost operation mode, and a normal operation mode are switched between. In the heating operation state, the room is heated by the heat of condensation of the refrigerant supplied from the compressor to the indoor heat exchanger via the cooling / heating switching unit, and the refrigerant that has passed through the indoor heat exchanger and has been decompressed by the first expansion valve is guided to the third outdoor heat exchange unit via the refrigerant piping.

[0065] According to the control method for an air conditioner according to a fifth aspect of the present disclosure, in the heating operation state, regardless of whether the operation mode switching unit switches between the first defrost operation mode, the second defrost operation mode, and the normal operation mode, the third outdoor heat exchange unit functions as an evaporator and is not a destination of refrigerant supplied from the compressor without passing through the indoor heat exchanger. The third outdoor heat exchange unit, which is part of the outdoor heat exchanger, is excluded from the destination of refrigerant in the first defrost operation mode and the second defrost operation mode. For example, if the heat exchange capacities of the first outdoor heat exchange unit and the second outdoor heat exchange unit are set to be equal, the destination of refrigerant in the defrost operation mode can be less than half of the entire outdoor heat exchanger. This allows the temperature of the refrigerant used for defrosting at the destination of the refrigerant to be maintained high, thereby shortening the time required for defrosting.

[0066] Furthermore, according to the control method for an air conditioner according to the fifth aspect of the present disclosure, in heating operation, the third outdoor heat exchanger functions as an evaporator, so there is no need to install new piping, valves, etc. for supplying refrigerant from the compressor to the third outdoor heat exchanger without passing through the indoor heat exchanger. As a result, it is possible to perform defrost operation that shortens the time required to defrost the outdoor heat exchanger without increasing manufacturing costs and without stopping heating by the indoor heat exchanger.

[0067] REFERENCE SIGNS LIST 10 Compressor 20 Indoor heat exchanger 30 Outdoor heat exchanger 31 First outdoor heat exchange section 32 Second outdoor heat exchange section 33 Third outdoor heat exchange section 40 Four-way valve (cooling / heating switching section) 50 First expansion valve 60 Operation mode switching section 61 Check valve 62 Second expansion valve 63 Third expansion valve 64 Fourth expansion valve 65, 66 Three-way valve 70 Control section 100 Air conditioning device L1 Refrigerant piping

Claims

1. A compressor that compresses and discharges a refrigerant; an indoor heat exchanger; an outdoor heat exchanger having a first outdoor heat exchange section, a second outdoor heat exchange section, and a third outdoor heat exchange section; a cooling / heating switching section that switches between a heating operation state in which the refrigerant discharged from the compressor is supplied to the indoor heat exchanger and a cooling operation state in which the refrigerant discharged from the compressor is supplied to the outdoor heat exchanger; a refrigerant piping that circulates the refrigerant between the cooling / heating switching section and the third outdoor heat exchange section via the indoor heat exchanger; and a first expansion valve that is arranged in the refrigerant piping between the indoor heat exchanger and the outdoor heat exchanger. an operation mode switching unit that switches between a first defrost operation mode in the heating operation state, in which a portion of the refrigerant discharged from the compressor to the cooling / heating switching unit is guided to the first outdoor heat exchange unit, and the refrigerant that has passed through the first outdoor heat exchange unit and the refrigerant that has passed through the third outdoor heat exchange unit are joined together, and the refrigerant is guided to the compressor via the second outdoor heat exchange unit; a second defrost operation mode in which a portion of the refrigerant discharged from the compressor to the cooling / heating switching unit is guided to the second outdoor heat exchange unit, and the refrigerant that has passed through the second outdoor heat exchange unit and the refrigerant that has passed through the third outdoor heat exchange unit are joined together, and the refrigerant is guided to the compressor via the first outdoor heat exchange unit; and a normal operation mode in which the refrigerant that has passed through the third outdoor heat exchange unit is guided to both the first outdoor heat exchange unit and the second outdoor heat exchange unit, and the refrigerant that has passed through the first outdoor heat exchange unit and the refrigerant that has passed through the second outdoor heat exchange unit are joined together, and the normal operation mode a control unit that controls the cooling / heating switching unit and the operation mode switching unit.

2. An air conditioning apparatus as described in claim 1, wherein the first outdoor heat exchange unit is disposed above the second outdoor heat exchange unit in the vertical direction, and the control unit controls the operation mode switching unit to switch to the normal operation mode after executing the second defrost operation mode following the first defrost operation mode.

3. The air conditioner according to claim 2, wherein the third outdoor heat exchange section is disposed below the second outdoor heat exchange section in the vertical direction.

4. An air conditioning apparatus as described in any one of claims 1 to 3, wherein the operation mode switching unit has a second expansion valve that adjusts the flow rate of the refrigerant discharged from the compressor to the cooling / heating switching unit and guided to the first outdoor heat exchange unit or the second outdoor heat exchange unit, and the control unit controls the opening degree of the second expansion valve so that the temperature of the refrigerant that has passed through the first outdoor heat exchange unit in the first defrost operation mode is 10°C or higher, and so that the temperature of the refrigerant that has passed through the second outdoor heat exchange unit in the second defrost operation mode is 10°C or higher.

5. A method for controlling an air conditioner, comprising: the air conditioner; a compressor that compresses and discharges a refrigerant; an indoor heat exchanger; an outdoor heat exchanger having a first outdoor heat exchange section, a second outdoor heat exchange section, and a third outdoor heat exchange section; a cooling / heating switching section that switches between a heating operation state in which the refrigerant discharged from the compressor is supplied to the indoor heat exchanger and a cooling operation state in which the refrigerant discharged from the compressor is supplied to the outdoor heat exchanger; a refrigerant piping that circulates the refrigerant between the cooling / heating switching section and the third outdoor heat exchange section via the indoor heat exchanger; and a first expansion valve arranged in the refrigerant piping between the indoor heat exchanger and the outdoor heat exchanger. an operation mode switching unit that switches, in the heating operation state, between a first defrosting operation mode in which a portion of the refrigerant discharged from the compressor to the cooling / heating switching unit is guided to the first outdoor heat exchange unit, a second defrosting operation mode in which a portion of the refrigerant discharged from the compressor to the cooling / heating switching unit is guided to the second outdoor heat exchange unit, and a normal operation mode in which the refrigerant that has passed through the third outdoor heat exchange unit is guided to both the first outdoor heat exchange unit and the second outdoor heat exchange unit, a control step of controlling the operation mode switching unit so that, in the first defrost operation mode, the refrigerant that has passed through the first outdoor heat exchange unit and the refrigerant that has passed through the third outdoor heat exchange unit are merged and the refrigerant is guided to the compressor via the second outdoor heat exchange unit; in the second defrost operation mode, the refrigerant that has passed through the second outdoor heat exchange unit and the refrigerant that has passed through the third outdoor heat exchange unit are merged and the refrigerant is guided to the compressor via the first outdoor heat exchange unit; and in the normal operation mode, the refrigerant that has passed through the first outdoor heat exchange unit and the refrigerant that has passed through the second outdoor heat exchange unit are merged and the refrigerant is guided to the compressor via the first outdoor heat exchange unit.

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