Air conditioner and method for controlling air conditioner

Abstract

To execute a defrosting operation in which a time required for defrosting an outdoor heat exchanger is shortened without increasing a manufacturing cost and without stopping heating by an indoor heat exchanger.SOLUTION: An outdoor heat exchanger 30 including a compressor 10, an indoor heat exchanger 20, a four way valve 40, a first outdoor heat exchanger portion 31, a second outdoor heat exchanger portion 32, and a third outdoor heat exchanger portion 33; An air conditioner 100 includes an operation mode switching unit 60 that switches between a first defrosting operation mode in which a portion of refrigerant discharged from a compressor 10 to a four way valve 40 is guided to a first outdoor heat exchanger unit 31, a second defrosting operation mode in which a portion of the refrigerant discharged from the compressor 10 to the four way valve 40 is guided to a second outdoor heat exchanger unit 32, and a normal operation mode in which refrigerant that has passed through a third outdoor heat exchanger unit 33 is guided to both the first outdoor heat exchanger unit 31 and the second outdoor heat exchanger unit 32, and a control unit 70 that controls the four way valve 40 and the operation mode switching unit 60.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Conventionally, there is 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. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6021940 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the air conditioning apparatus disclosed in Patent Document 1, for example, 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. Patent Document 1 also indicates that the outdoor heat exchanger can be divided into any number greater than two, but this requires the installation of additional solenoid valves and flow control devices depending on the number of divisions, 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. [Means for solving the problem]

[0007] In order to solve the above problems, the air conditioning apparatus of the present disclosure employs the following measures. 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 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 operation mode 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, and a second expansion valve that, in the heating operation state, guides a portion of the refrigerant discharged from the compressor to the cooling / heating switching unit to the first outdoor heat exchange unit and controls the refrigerant that has passed through the first outdoor heat exchange unit and the third outdoor heat exchange unit to flow through the first outdoor heat exchange unit. and a control unit for controlling the cooling / heating switching unit and the operation mode switching unit.

[0008] 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 operation mode switching unit and the third outdoor heat exchanger 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 exchanger; and an operation mode switching unit that switches between a second defrost operation mode in which a portion of 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 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. [Effects of the Invention]

[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. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing a refrigerant circuit of an air conditioner according to an embodiment of the present disclosure, illustrating a state in which a normal operation mode is executed in a heating operation state. [Figure 2] 1 is a diagram showing a refrigerant circuit of an air conditioner 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. [Figure 3] 1 is a diagram showing a refrigerant circuit of an air conditioner 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. [Figure 4] 1 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. [Figure 5] 4 is a flowchart illustrating a control method for an air conditioning apparatus according to an embodiment of the present disclosure. [Figure 6] FIG. 10 is a diagram showing a first modified example of the outdoor heat exchanger. [Figure 7] FIG. 10 is a diagram showing a second modified example of the outdoor heat exchanger. DETAILED DESCRIPTION OF THE INVENTION

[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 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.

[0012] 1 to 3, an 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, portions through which refrigerant R flows are indicated by solid lines, and portions through which 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 heating operation, 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 air with the condensation heat released when the refrigerant R condenses, thereby heating the room. In cooling operation, the indoor heat exchanger 20 functions as an evaporator when refrigerant R decompressed by the first expansion valve 50 is supplied, and cools the air with the heat of vaporization when the refrigerant R evaporates, thereby cooling the room.

[0015] The outdoor heat exchanger 30 is a device installed outdoors, and in the heating operation state, when refrigerant R decompressed by the first expansion valve 50 is supplied, it 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 the 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 the heat of the refrigerant R into 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. In addition, 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 piping L1 is a piping 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 piping 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 piping 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 decompresses 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 decompresses 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 in order 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 in order to defrost the second outdoor heat exchange unit 32.

[0021] The normal operation mode is an operation mode in which, when frost formation on the outdoor heat exchanger 30 is not detected, 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, and the refrigerant R is evaporated by heat exchange with the 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, and condenses the refrigerant R by heat exchange with the 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 section 31 and / or the second outdoor heat exchange section 32. The opening degree of the second expansion valve 62 is adjusted by the control section 70 so that the temperature of the refrigerant R that has passed through the first outdoor heat exchange section 31 becomes 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 section 32 becomes 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 so that the second expansion valve 62 is closed and 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 indoor heat exchanger 20. The control unit 70 also controls the three-way valve 65 so that the third expansion valve 63 is open and the refrigerant R that has passed through the third outdoor heat exchange unit 33 and the first outdoor heat exchange unit 31 passes through the three-way valve 65 and is guided to the compressor 10. The control unit 70 also controls the four-way valve 66 so that the fourth expansion valve 64 is open and the refrigerant R that has passed through the third outdoor heat exchange unit 33 and the second outdoor heat exchange unit 32 passes through the three-way valve 66 and is guided 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 valve 65 and the three-way valve 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 with 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. In addition, the control unit 70 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 states 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 conditioner 100 of this embodiment will be described with reference to Fig. 5. Fig. 5 is a flowchart showing the control method for the air conditioner 100 of this embodiment.

[0031] In step S101, the control unit 70 determines whether or not to perform the heating operation, and 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 bringing the system into a cooling operation state.

[0034] In step S104, the control unit 70 determines whether frost has formed on the outdoor heat exchanger 30, and if YES, proceeds to step S105, and if NO, 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, and if YES, the process proceeds to step S109, and if NO, step S101 is executed 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 processing shown in the above flowchart, 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 circulate 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 at positions where they 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 the 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 possible to make the moisture contained in the outdoor air passing through the second outdoor heat exchange section 32 less likely 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 where they do not overlap along the flow direction FD of the outdoor air, 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 where they overlap along the flow direction FD of the outdoor air. 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] According to the air conditioner 100 of the present embodiment described above, the following actions and effects are achieved.

[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 conditioner 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 makes it possible to maintain a high temperature of refrigerant R used for defrosting at the destination of refrigerant R, 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 for supplying refrigerant from the compressor 10 to the third outdoor heat exchanger 33 without passing through the indoor heat exchanger 20. Therefore, it is possible to perform a defrosting operation 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, causing the normal operation mode to be switched to.

[0050] According to the air conditioning apparatus 100 of this embodiment, in the heating operation state, the third outdoor heat exchange section 33 is disposed upstream of the first outdoor heat exchange section 31 and the second outdoor heat exchange section 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 section 33 below the second outdoor heat exchange section 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 section 33 is higher than the temperature of the refrigerant R flowing through the first outdoor heat exchange section 31 and the second outdoor heat exchange section 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 apparatus 100 of this embodiment, the temperature of the refrigerant R that has passed through the first outdoor heat exchange unit 31 is set to 10°C or higher in the first defrost operation mode, and the temperature of the refrigerant R that has passed through the second outdoor heat exchange unit 32 is set to 10°C or higher in the second defrost operation mode, thereby making it possible to maintain appropriate defrosting performance and shorten the time required for defrosting.

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

[0053] An air conditioner 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. and a control unit (70) for controlling 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 conditioner 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. to supply 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 state decreases as it advances downstream, resulting in a decrease in the refrigerant temperature.

[0059] The air conditioning apparatus according to a third aspect of the present disclosure is the second aspect, further comprising the following configuration: In other words, 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 any one of the first to third aspects, further including the following configuration: The operation mode switching unit has a second expansion valve (62) 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 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 appropriately maintain 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 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.

[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 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.

[0065] According to the air conditioner control method of the 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 set to 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 exchange unit functions as an evaporator, so there is no need to install new piping, valves, etc. to supply 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. [Explanation of symbols]

[0067] 10 Compressor 20 Indoor heat exchanger 30 Outdoor heat exchanger 31 1st outdoor heat exchange section 32 2nd outdoor heat exchange section 33 Third outdoor heat exchange section 40 Four-way valve (heating / cooling 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 Unit 100 Air conditioning equipment 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 portion, a second outdoor heat exchange portion, and a third outdoor heat exchange portion; 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 pipe 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 disposed 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. In the vertical direction, the first outdoor heat exchange unit is disposed above the second outdoor heat exchange unit, The air conditioner according to claim 1 , wherein 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 unit is disposed below the second outdoor heat exchange unit in the vertical direction.

4. the operation mode switching unit has a second expansion valve that adjusts a 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, 4. The air conditioning apparatus according to claim 1, wherein the control unit controls the opening degree of the second expansion valve so that the temperature of the refrigerant passing through the first outdoor heat exchange unit is 10°C or higher in the first defrost operation mode, and the temperature of the refrigerant passing through the second outdoor heat exchange unit is 10°C or higher in the second defrost operation mode.

5. A control method for an air conditioning apparatus, comprising: The air conditioning device is 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 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 pipe 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 disposed 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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