Air Conditioning Equipment

Abstract

To avoid an increase in the influences of lower heat exchanging efficiency when performing frost formation processing for a long time.SOLUTION: An air conditioner includes a refrigerant circuit, and a control part, the refrigerant circuit including an indoor heat exchanger 13, the control part serving for cleaning operation to clean the indoor heat exchanger 13 when the cleaning of the indoor heat exchanger 13 is requested. The control part 40 performs frost formation processing and washing processing in the cleaning operation. The frost formation processing is to cause dew condensation on the surface of the indoor heat exchanger 13 and furthermore to form frost on the indoor heat exchanger 13. The washing processing is to cause dew condensation on the surface of the indoor heat exchanger 13 after the frost formation processing so that the surface of the indoor heat exchanger 13 is washed with dew condensation water.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] Regarding air conditioning equipment. [Background technology]

[0002] Conventionally, a technical idea has been known in which an indoor heat exchanger is cleaned by freezing and thawing the indoor heat exchanger after a heating operation (Patent Literature 1 (JP 2018-189262 A)). Summary of the Invention [Problem to be solved by the invention]

[0003] The above-mentioned Patent Document 1 discloses an example of an air conditioner in which frost (ice) adheres to an indoor heat exchanger. However, frost adhered to the indoor heat exchanger increases the ventilation resistance of the indoor heat exchanger, and there is a risk of the heat exchange efficiency of the indoor heat exchanger decreasing. In order to thoroughly clean the indoor heat exchanger, it is possible to carry out a frost treatment for a long period of time, but when the frost treatment is carried out for a long period of time, the influence of the decrease in heat exchange efficiency becomes large. [Means for solving the problem]

[0004] An air conditioner according to a first aspect includes a refrigerant circuit and a control unit. The refrigerant circuit includes an indoor heat exchanger. The control unit performs a cleaning operation, which is an operation for cleaning the indoor heat exchanger, when cleaning of the indoor heat exchanger is required. In the cleaning operation, the control unit performs a frosting process and a water washing process. The frosting process is a process for causing condensation on the surface of the indoor heat exchanger and further causing frost to form on the indoor heat exchanger. The water washing process is a process for causing condensation on the surface of the indoor heat exchanger after the frosting process and washing the surface of the indoor heat exchanger with the condensed water.

[0005] The air conditioner according to the first aspect performs frost treatment and water flushing in cleaning operation. With this configuration, the indoor heat exchanger can be cleaned while shortening the time for which frost treatment is performed in cleaning operation. This makes it possible to suppress a decrease in the heat exchange efficiency of the indoor heat exchanger during cleaning operation.

[0006] An air conditioner of a second aspect is the air conditioner of the first aspect, in which the frosting process freezes condensed water by lowering the temperature of the refrigerant flowing through the indoor heat exchanger to a temperature at which moisture contained in the indoor air can freeze in the indoor heat exchanger or lower, and the water washing process causes condensation to occur at a refrigerant temperature higher than the refrigerant temperature during the frosting process.

[0007] An air conditioner according to a third aspect is the air conditioner according to the first or second aspect, further comprising an expansion valve. The control unit adjusts the opening degree of the expansion valve to control the temperature of the refrigerant flowing through the indoor heat exchanger.

[0008] An air conditioner according to a fourth aspect is the air conditioner according to any one of the first aspect to the third aspect, wherein the target evaporation temperature during frosting treatment is lower than the target evaporation temperature during water washing treatment.

[0009] An air conditioner according to a fifth aspect is the air conditioner according to any one of the first to fourth aspects, wherein the amount of humidity dehumidified from the indoor air by the frosting process is less than the amount of humidity dehumidified from the indoor air by the water washing process.

[0010] According to this configuration, the decrease in the heat exchange efficiency of the indoor heat exchanger during frost treatment can be more reliably suppressed.

[0011] An air conditioner according to a sixth aspect is the air conditioner according to any one of the first aspect to the fifth aspect, wherein the implementation time of the frosting process is shorter than the implementation time of the water flushing process.

[0012] According to this configuration, the decrease in the heat exchange efficiency of the indoor heat exchanger during frost treatment can be more reliably suppressed.

[0013] An air conditioner according to a seventh aspect is the air conditioner according to any one of the first aspect to the sixth aspect, further comprising a compressor. The air conditioner continues to operate the compressor while performing the frosting treatment and the water flushing treatment.

[0014] According to this configuration, the operating time of the cleaning operation can be shortened.

[0015] An air conditioner according to an eighth aspect is the air conditioner according to any one of the first to sixth aspects, wherein a predetermined time is left between the frosting process and the water flushing process. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram illustrating the configuration of an air conditioning device. [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4] FIG. 2 is a block diagram showing a configuration of a control unit. [Diagram 5] FIG. [Figure 6] 13 is a flowchart of a cleaning operation. [Figure 7] FIG. [Figure 8] FIG. [Figure 9] FIG. [Figure 10] FIG. [Figure 11] FIG. [Figure 12] FIG. [Figure 13] FIG. [Figure 14] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] First Embodiment The air conditioner 1 according to this embodiment will be described below with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed description of already well-known matters or duplicated description of substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art. Note that each figure is not necessarily illustrated precisely. For example, as shown in FIG. 1, the expansion valve 104 according to this embodiment is connected to the outdoor circuit part of the air conditioner outdoor unit 2 and is located at a position away from the air conditioner indoor unit 10. However, for convenience of explanation, the expansion valve 104 is illustrated in FIG. 5, and FIG. 7 to FIG. 14, which are diagrams relating to the air conditioner indoor unit 10. Also, in each figure, the area where the frosting process is performed is indicated by horizontal hatching, and the area where the water washing process is performed is indicated by vertical hatching (see FIG. 5, FIG. 7 to FIG. 14).

[0018] (1) Configuration of Air Conditioner 1 As shown in Fig. 1, an air conditioner 1 according to this embodiment includes an air conditioner outdoor unit 2 and an air conditioner indoor unit 10. The air conditioner 1 includes a refrigerant circuit 200 filled with refrigerant. The refrigerant circuit 200 is configured by connecting an outdoor circuit section housed in the air conditioner outdoor unit 2 and an indoor circuit section housed in the air conditioner indoor unit 10 by gas side connection piping 117a and liquid side connection piping 117b (see Fig. 1).

[0019] (2) Configuration of air conditioning outdoor unit 2 A compressor 101, a four-way switching valve 102, an outdoor heat exchanger 103, and an expansion valve 104 are connected to an outdoor circuit portion in the air conditioning outdoor unit 2 (see FIG. 1).

[0020] The compressor 101 is a device that draws in low-pressure refrigerant in a refrigeration cycle through a suction pipe 111a, compresses the refrigerant using a compression mechanism (not shown), and discharges the compressed refrigerant to a discharge pipe 111b.

[0021] The compressor 101 is not limited to a specific type, and may be, for example, a rotary or scroll type volumetric compressor. A compression mechanism (not shown) of the compressor 101 is driven by a compressor motor (not shown). The compression mechanism is driven by the compressor motor to compress the refrigerant. Here, the compressor motor is a motor whose rotation speed can be controlled by an inverter. The capacity of the compressor 101 is controlled by controlling the rotation speed of the compressor motor by a control unit 40 described later. The compression mechanism of the compressor 101 may be driven by a prime mover other than a motor (for example, an internal combustion engine).

[0022] The four-way switching valve 102 is a switching valve for switching the direction of the refrigerant flow in the refrigerant circuit 200. As shown in FIG. 1, the discharge pipe 111b is connected to the first port P1 of the four-way switching valve 102. The suction pipe 111a is connected to the third port P3 of the four-way switching valve 102 with the accumulator 120 in between. The accumulator 120 separates the liquid refrigerant from the gas refrigerant. The four-way switching valve 102 is switchable between a first state (a state shown by a solid line in FIG. 1) in which the first port P1 and the fourth port P4 communicate with each other and the second port P2 and the third port P3 communicate with each other, and a second state (a state shown by a dotted line in FIG. 1) in which the first port P1 and the second port P2 communicate with each other and the third port P3 and the fourth port P4 communicate with each other.

[0023] The outdoor heat exchanger 103 is a cross-fin type fin-and-tube heat exchanger. An outdoor fan 123 for sending outdoor air to the outdoor heat exchanger 103 is provided near the outdoor heat exchanger 103. One end of the outdoor heat exchanger 103 is connected to a fourth port P4 of the four-way switching valve 102. The other end of the outdoor heat exchanger 103 is connected to the expansion valve 104. The second port P2 of the four-way switching valve 102 is connected to the indoor heat exchanger 13 via the gas side connection pipe 117a.

[0024] The expansion valve 104 is a mechanism for adjusting the pressure and flow rate of the refrigerant flowing through the outdoor circuit section. The expansion valve 104 is, for example, an electrically operated expansion valve with a variable opening. However, the expansion valve 104 is not limited to an electrically operated expansion valve, and any mechanism generally used as an expansion mechanism in a refrigeration cycle device may be appropriately selected. The control unit 40, which will be described later, adjusts the opening of the expansion valve 104 to control the temperature of the refrigerant.

[0025] (3) Configuration of the air conditioning indoor unit 10 As shown in Fig. 1, an auxiliary heat exchanger 13a and a main heat exchanger 13b are connected to the indoor circuit section. The auxiliary heat exchanger 13a and the main heat exchanger 13b are cross-fin type fin-and-tube heat exchangers having a plurality of heat transfer fins 21a and a plurality of heat transfer tubes 21b. Hereinafter, the auxiliary heat exchanger 13a and the main heat exchanger 13b may be collectively referred to as the indoor heat exchanger 13. An indoor fan 14 for sending indoor air to the indoor heat exchanger 13 is provided near the indoor heat exchanger 13.

[0026] (4) Detailed configuration of the air conditioning indoor unit 10 Fig. 2 is a perspective view of the air conditioning indoor unit 10 during operation. Also, Fig. 3 is a cross-sectional view of the air conditioning indoor unit 10. As shown in Figs. 2 and 3, the air conditioning indoor unit 10 is equipped with a main body casing 11, an indoor heat exchanger 13, an indoor fan 14, a bottom frame 16, and a control unit 40. Also, as shown in Fig. 3, in the air conditioning indoor unit 10, the auxiliary heat exchanger 13a is located on the windward side, and the main heat exchanger 13b is located on the leeward side.

[0027] (4-1) Main casing 11 The main body casing 11 has a top surface 11a, a front panel 11b, a back panel 11c, and a lower horizontal panel 11d. The main body casing 11 accommodates an indoor heat exchanger 13, an indoor fan 14, a bottom frame 16, a filter 24, and a control unit 40 therein.

[0028] Top surface 11a is located at the top of main body casing 11, and an intake port 12 is provided at the front of top surface 11a.

[0029] The front panel 11b constitutes the front portion of the air conditioning indoor unit 10, and has a curved shape with no suction opening.

[0030] (4-2) Filter 24 A filter 24 is disposed between the air inlet 12 and the indoor heat exchanger 13. The filter 24 removes dust contained in the air sucked in from the air inlet 12.

[0031] (4-3) Indoor heat exchanger 13 In this embodiment, the indoor heat exchanger 13 has an auxiliary heat exchanger 13a consisting of one row of heat transfer tubes 21b and a main heat exchanger 13b consisting of multiple rows of heat transfer tubes 21b. A refrigerant flows inside the indoor heat exchanger 13. The indoor heat exchanger 13 exchanges heat between the refrigerant flowing inside and the indoor air.

[0032] As described above, the indoor heat exchanger 13 (auxiliary heat exchanger 13a and main heat exchanger 13b) is a cross-fin type fin-and-tube heat exchanger having a plurality of heat transfer fins 21a and a plurality of heat transfer tubes 21b. Indoor air passes between the plurality of heat transfer fins 21a. During heat exchange, air passes between the plurality of heat transfer fins 21a and at the same time, refrigerant flows through the plurality of heat transfer tubes 21b. The heat transfer tube 21b is folded back multiple times and penetrates one heat transfer fin 21a multiple times.

[0033] (4-4) Indoor fan 14 The indoor fan 14 according to this embodiment is a cross-flow fan. As shown in Fig. 3, the indoor fan 14 is located below the indoor heat exchanger 13. The indoor fan 14 sends air taken in from inside the room to the indoor heat exchanger 13. The indoor air that has passed through the indoor heat exchanger 13 is blown out into the room from the air outlet 15. The indoor fan 14 and the indoor heat exchanger 13 are attached to a bottom frame 16.

[0034] (4-5) Airflow adjustment blade 31 In the air conditioning device 1 according to this embodiment, the air outlet 15 is provided at the bottom of the main casing 11. An airflow direction adjustment blade 31 that changes the direction of air blown out from the air outlet 15 is rotatably attached to the air outlet 15. The airflow direction adjustment blade 31 is driven by a motor (not shown). The airflow direction adjustment blade 31 not only changes the air blowing direction, but can also open and close the air outlet 15. The airflow direction adjustment blade 31 can take multiple positions with different inclination angles.

[0035] (4-6) Outlet passage 18 In the air conditioning device 1 according to this embodiment, an outlet flow path is formed from the outlet 15 along the scroll 17 of the bottom frame 16. The outlet 15 is connected to the inside of the main body casing 11 by the outlet flow path .

[0036] When the indoor fan 14 is operated, indoor air is sucked into the indoor fan 14 through the suction port 12 and the indoor heat exchanger 13, and then blown out from the indoor fan 14 through the blow-out flow path 18 through the blow-out port 15.

[0037] (4-7) Control unit 40 The control unit 40 is located to the right of the indoor heat exchanger 13 and the indoor fan 14 when the main body casing 11 is viewed from the front panel 11b.

[0038] The control unit 40 is realized by a computer. The control unit 40 includes a control and arithmetic unit and a storage unit. A block diagram showing the schematic configuration of the control unit 40 is shown in FIG. 4. The control unit 40 has, as functional units, a cooling operation control unit 42, a heating operation control unit 43, and a cleaning operation control unit 46. Under the control of the control unit 40, the air conditioning device 1 can perform cooling operation, heating operation, and cleaning operation.

[0039] The control arithmetic device of the control unit 40 can be a processor such as a CPU or a GPU. The control arithmetic device reads a program stored in a storage device and performs a predetermined arithmetic process according to the program. Furthermore, the control arithmetic device can write the results of the calculations to the storage device and read information stored in the storage device according to the program. The storage device can be used as a database.

[0040] The control unit 40 shown in this embodiment is merely an example. The air conditioning device 1 may realize functions similar to those exerted by the control unit 40 according to this embodiment by hardware such as a logic circuit, or may realize the functions by a combination of hardware and software.

[0041] Furthermore, the control unit 40 may not have some or all of the functions described in this embodiment. For example, some or all of the functions of the control unit 40 described in this embodiment may be realized by a server or the like installed in a location separate from the air conditioning device 1.

[0042] In the cleaning operation, the control unit 40 according to the present embodiment performs a frosting process in which condensation occurs on the surfaces of the auxiliary heat exchanger 13a and the main heat exchanger 13b, and further frosts the auxiliary heat exchanger 13a and the main heat exchanger 13b. In addition, the control unit 40 according to the present embodiment performs a water washing process in which condensation occurs on the surfaces of the auxiliary heat exchanger 13a and the main heat exchanger 13b after the frosting process, and the surfaces of the auxiliary heat exchanger 13a and the main heat exchanger 13b are washed with the condensed water. Details will be described later.

[0043] (4-8) Various sensors Various sensors, such as a first thermistor 105, a third thermistor 107, a fourth thermistor 108, and a fifth thermistor 109, are attached to predetermined locations in the air conditioner 1 as appropriate. The control unit 40 receives at least any of the following detected by these sensors: room temperature, surrounding outside air temperature, the temperature and pressure of the refrigerant sucked into the compressor 101, the temperature and pressure of the refrigerant discharged from the compressor 101, the temperature of the refrigerant in the indoor heat exchanger 13, and the temperature of the refrigerant in the outdoor heat exchanger 103. The control unit 40 controls the operation of each part of the air conditioner 1, such as the indoor fan 14, the compressor 101, the four-way switching valve 102, and the expansion valve 104, based on the detection values ​​of the various sensors.

[0044] In this embodiment, the control unit 40 can confirm the temperature of the refrigerant flowing through the indoor heat exchanger 13 by receiving the temperatures of the refrigerant detected by the first thermistor 105, the third thermistor 107, the fourth thermistor 108, and the fifth thermistor 109. In this embodiment, the first thermistor 105 is attached to a pipe between the expansion valve 104 and the auxiliary heat exchanger 13a. The third thermistor 107 is attached to a pipe between the auxiliary heat exchanger 13a and the main heat exchanger 13b. The fourth thermistor 108 is attached to the main heat exchanger 13b. The fifth thermistor 109 is attached between the main heat exchanger 13b and the compressor 101 (see Figs. 1 and 5). However, the method of confirming the temperature of the refrigerant flowing through the indoor heat exchanger 13 is not limited to this and can be changed as appropriate.

[0045] (5) Operation of Air Conditioner 1 The following describes the operation of the various devices of the air conditioner 1 when the air conditioner 1 performs cooling operation, heating operation, and cleaning operation.

[0046] It should be noted that in the air conditioner 1, the four-way switching valve 102 can switch the flow of the refrigerant to either the first cycle or the second cycle.

[0047] (5-1) Cooling operation In cooling operation, the refrigerant flows in a first cycle. In the first cycle, the four-way switching valve 102 is set to a first state (a state shown by a solid line in FIG. 1). When the compressor 101 is operated in the first state, a vapor compression refrigeration cycle is performed in the refrigerant circuit 200, in which the outdoor heat exchanger 103 serves as a condenser of the refrigerant, and the auxiliary heat exchanger 13a and the main heat exchanger 13b serve as evaporators of the refrigerant.

[0048] The high-pressure refrigerant discharged from the compressor 101 exchanges heat with outdoor air in the outdoor heat exchanger 103 and condenses. The refrigerant that has passed through the outdoor heat exchanger 103 is reduced in pressure when passing through the expansion valve 104. The refrigerant that has been reduced in pressure by the expansion valve 104 exchanges heat with indoor air in the auxiliary heat exchanger 13a and the main heat exchanger 13b and evaporates. The refrigerant that has passed through the auxiliary heat exchanger 13a and the main heat exchanger 13b is drawn into the compressor 101 and compressed.

[0049] (5-2) Heating operation In the heating operation, the refrigerant flows in the second cycle. In the second cycle, the four-way switching valve 102 is set to the second state (the state shown by the dotted line in FIG. 1). When the compressor 101 is operated in the second state, a vapor compression refrigeration cycle is performed in the refrigerant circuit 200, in which the outdoor heat exchanger 103 serves as an evaporator of the refrigerant, and the auxiliary heat exchanger 13a and the main heat exchanger 13b serve as condensers of the refrigerant.

[0050] The high-pressure refrigerant discharged from the compressor 101 exchanges heat with the indoor air in the auxiliary heat exchanger 13a and the main heat exchanger 13b and is condensed. The condensed refrigerant is reduced in pressure when passing through the expansion valve 104, and then evaporates by exchanging heat with the outdoor air in the outdoor heat exchanger 103. The refrigerant that has passed through the outdoor heat exchanger 103 is drawn into the compressor 101 and compressed.

[0051] (5-3) Washing operation The air conditioner 1 according to this embodiment is capable of executing a cleaning operation. The operation of the air conditioner 1 during the cleaning operation is controlled by the cleaning operation control unit 46. During the cleaning operation, a water washing process and a frosting process are carried out.

[0052] (5-3-1) Frost treatment The frosting process is a process in which condensation occurs on the surface of the indoor heat exchanger 13, and further frosts the indoor heat exchanger 13. The operation of each part of the air conditioning apparatus 1 during the frosting process is controlled by a frosting process control unit 47.

[0053] In the frosting process, the temperature of the refrigerant flowing through the indoor heat exchanger 13 is lowered to a temperature at which the moisture contained in the indoor air can freeze in the indoor heat exchanger 13 or lower, thereby freezing the condensed water.

[0054] For ease of explanation, "the temperature at which moisture contained in the indoor air can freeze in the indoor heat exchanger 13" will be referred to as "freezing temperature" below.

[0055] The flow of the refrigerant during frosting treatment is the first cycle, similar to the flow of the refrigerant during cooling operation. Therefore, during frosting operation, the four-way switching valve 102 is set to the first state (solid line in FIG. 1). When the compressor 101 is operated in the first state, a vapor compression refrigeration cycle is performed in the refrigerant circuit 200, in which the outdoor heat exchanger 103 serves as a refrigerant condenser, and the auxiliary heat exchanger 13a and the main heat exchanger 13b serve as refrigerant evaporators.

[0056] In the air conditioning apparatus 1 of this embodiment, a first frosting process is performed, which is a process in which the temperature of the refrigerant flowing through the auxiliary heat exchanger 13a and the main heat exchanger 13b is lowered below the freezing point to cause condensation water formed on the surfaces of the auxiliary heat exchanger 13a and the main heat exchanger 13b to form frost.

[0057] When the first frosting process is performed, the frosting process control unit 47 controls the frequency of the compressor 101 and the opening degree of the expansion valve 104 so that the temperature of the refrigerant flowing through the auxiliary heat exchanger 13a and the main heat exchanger 13b becomes below the freezing temperature.

[0058] (5-3-2) Water washing treatment The flushing process is a process carried out after the frosting process, in which condensation occurs on the surface of the indoor heat exchanger 13 and the condensed water is used to wash the surface of the indoor heat exchanger 13. The operation of each part of the air conditioning apparatus 1 during the flushing process is controlled by the flushing process control unit 48.

[0059] The flushing process causes condensation at a refrigerant temperature higher than that during the frosting process. In other words, the flushing process is a process in which condensation occurs by raising the temperature of the refrigerant flowing through the indoor heat exchanger 13 above the freezing temperature. Preferably, the refrigerant temperature during the flushing process is controlled by the flushing process control unit 48 so that it is higher than the freezing temperature and equal to or lower than the dew point temperature of the indoor air.

[0060] The flow of the refrigerant during the flushing process is the first cycle, similar to the flow of the refrigerant during the cooling operation. Therefore, during the flushing process, the four-way switching valve 102 is set to the first state (solid line in FIG. 1). When the compressor 101 is operated in the first state, a vapor compression refrigeration cycle is performed in the refrigerant circuit 200, in which the outdoor heat exchanger 103 serves as a refrigerant condenser, and the auxiliary heat exchanger 13a and the main heat exchanger 13b serve as refrigerant evaporators.

[0061] In the air conditioner 1 according to this embodiment, a first water-flushing process is performed, which is a process for condensing moisture contained in the indoor air on the surfaces of the auxiliary heat exchanger 13a and the main heat exchanger 13b.

[0062] When the first flushing process is performed, the flushing process control unit 48 controls the frequency of the compressor 101, the opening degree of the expansion valve 104, and the rotation speed of the indoor fan 14 so that the temperature of the refrigerant flowing through the auxiliary heat exchanger 13a and the main heat exchanger 13b becomes higher than the freezing temperature.

[0063] Specifically, when the first flushing process is performed, the flushing process control unit 48 controls the frequency of the compressor 101, the opening degree of the expansion valve 104, the rotation speed of the indoor fan 14, and the rotation speed of the outdoor fan 123 so that the temperature detected by the first thermistor 105 is higher than the freezing temperature.

[0064] For example, when the temperature of the refrigerant detected by the first thermistor 105 is below the freezing temperature, the control unit 40 performs at least one of increasing the rotation speed of the indoor fan 14, decreasing the rotation speed of the outdoor fan 123, decreasing the frequency of the compressor 101, and decreasing the amount of pressure reduction by the expansion valve 104.

[0065] Furthermore, when the refrigerant temperature detected by the fourth thermistor 108 is higher than the refrigerant temperature detected by the first thermistor 105, the control unit 40 at least one of decreasing the rotation speed of the indoor fan 14 and increasing the frequency of the compressor 101. In this manner, the flushing process control unit 48 controls the indoor fan 14 and the compressor 101 so that condensation occurs over the entire area of ​​the indoor heat exchanger 13.

[0066] (5-3-3) Details of control during cleaning operation In this embodiment, the frosting process control unit 47 and the water washing process control unit 48 control each unit of the air conditioning apparatus 1 so that the target evaporation temperature during frosting process is lower than the target evaporation temperature during water washing process. Note that in this embodiment, the target evaporation temperature during frosting process and water washing process can be detected by using any one of the first thermistor 105, the third thermistor 107, and the fourth thermistor 108 according to the application.

[0067] In this embodiment, the frosting process control unit 47 and the water flushing process control unit 48 control each unit of the air conditioning device 1 so that the amount of moisture removed from the indoor air by the frosting process is less than the amount of moisture removed from the indoor air by the water flushing process. The amount of moisture removed by the frosting process is preferably less than half the amount of moisture removed by the water flushing process. In this embodiment, the amount of moisture removed by the frosting process and the water flushing process can be estimated based on the humidity detected by a humidity sensor (not shown), the indoor heat exchanger temperature, the air volume, and the like. However, the method of estimating the amount of moisture removed by the frosting process and the water flushing process is not limited to this, and may be selected as appropriate.

[0068] In this embodiment, the frosting process control unit 47 and the water flushing process control unit 48 control the various parts of the air conditioning apparatus 1 so that the implementation time of the frosting process is shorter than the implementation time of the water flushing process. The implementation time of the frosting process is preferably shorter than half the implementation time of the water flushing process. In this embodiment, the implementation times of the frosting process and the water flushing process can each be detected by a timer.

[0069] The first cleaning operation, which is a cleaning operation in which the first frosting process and the first water cleaning process are performed, will be described below. Note that, although details will be described later, the cleaning operation includes the first to ninth cleaning operations.

[0070] (5-3-4) Operation during cleaning The operation of each part of the air conditioning apparatus 1 during the first cleaning operation will be described below with reference to the flowchart shown in Fig. 6. Note that the flowchart shown in Fig. 6 is merely an example, and may be modified as appropriate within a range that does not contradict. For example, other steps not shown may be included before or after each step, and the order of each step may be modified as appropriate within a range that does not contradict each other.

[0071] In step S1 of FIG. 6, the cleaning operation control unit 46 determines whether or not a cleaning operation command has been received from a remote control or the like, and if a cleaning operation command has been received, proceeds to step S2, and if no cleaning operation command has been received, waits and continues to determine whether or not a cleaning operation command has been received.

[0072] The cleaning operation control unit 46 executes the first frosting process in step S2. As described above, the operation of each part of the air conditioner 1 during frosting process is controlled by the frosting process control unit 47. The frosting process control unit 47 executes the first frosting process, for example, by setting the target evaporation temperatures of the auxiliary heat exchanger 13a and the main heat exchanger 13b to -5 to -10°C, stopping the indoor fan 14 or operating it at a low speed, reducing the opening of the expansion valve 104, and controlling the frequency of the compressor 101 to 15 to 25 Hz. However, these controls are merely examples and can be changed as appropriate.

[0073] In step S3, the cleaning operation control unit 46 checks whether the temperature of the refrigerant flowing through the auxiliary heat exchanger 13a and the main heat exchanger 13b is equal to or lower than the freezing temperature. In this embodiment, the cleaning operation control unit 46 can check the temperature of the refrigerant flowing through the auxiliary heat exchanger 13a and the main heat exchanger 13b by receiving the refrigerant temperature detected by any one of the first thermistor 105, the third thermistor 107, and the fourth thermistor 108.

[0074] In step S4, the cleaning operation control unit 46 checks whether a predetermined time has elapsed since the start of the first frosting process. In this embodiment, the cleaning operation control unit 46 can check whether the predetermined time has elapsed by operating a timer at the start of step S2. Here, the predetermined time is, for example, 15 minutes. However, the predetermined time in step S4 is not limited to this as long as the implementation time of the first frosting process is shorter than the implementation time of the first water washing process. Therefore, the predetermined time in step S4 may be longer or shorter than 15 minutes.

[0075] In this embodiment, the implementation time of the first frosting process refers to the time from the start of step S2 to the end of step S5.

[0076] If the predetermined time has elapsed in step S4, the cleaning operation control unit 46 proceeds to step S5, and if the predetermined time has not elapsed, the cleaning operation control unit 46 continues with step S4.

[0077] The cleaning operation control unit 46 ends the first frosting process in step S5. Upon completion of the first frosting process, the control unit 40 proceeds to step S6 and starts the first water washing process.

[0078] The flushing operation control unit 46 executes the first flushing process in step S6. As described above, the operation of each part of the air conditioner 1 during the flushing process is controlled by the flushing process control unit 48. For example, the flushing process control unit 48 executes the first flushing process by setting the target evaporation temperature to 5°C, driving the indoor fan 14, opening the expansion valve 104 to a degree greater than during the first frosting process, and controlling the frequency of the compressor 101 to 60 Hz. However, these controls are merely examples and can be changed as appropriate.

[0079] In this embodiment, the cleaning operation control unit 46 does not leave a predetermined time between the frosting process and the water washing process. In other words, after the process of step S5 is performed, the process of step S6 is immediately started. Note that an example in which the cleaning operation control unit 46 leaves a predetermined time between the frosting process and the water washing process will be described later.

[0080] In addition, in this embodiment, the compressor 101 continues to operate during the frosting process and the water flushing process. In other words, in this embodiment, switching between the frosting process and the water flushing process is performed by adjusting the frequency of the compressor 101, the opening degree of the expansion valve 104, and the rotation speed of the indoor fan 14.

[0081] In step S7, the cleaning operation control unit 46 checks whether the temperature of the refrigerant flowing through the auxiliary heat exchanger 13a and the main heat exchanger 13b is higher than the refrigerant temperature during frost formation treatment.

[0082] If the temperature of the refrigerant flowing through the auxiliary heat exchanger 13a and the main heat exchanger 13b is higher than the refrigerant temperature during frosting treatment (Yes in step S7), the cleaning operation control unit 46 proceeds to step S8. Otherwise (No in step S7), the cleaning operation control unit 46 continues the process of step S6.

[0083] In step S8, the cleaning operation control unit 46 determines whether a predetermined time has elapsed since the start of the first frosting process. In this embodiment, the cleaning operation control unit 46 can check whether the predetermined time has elapsed by operating a timer at the start of step S6. Here, the predetermined time is, for example, 90 minutes. However, the predetermined time in step S8 is not limited to this as long as the implementation time of the first frosting process is shorter than the implementation time of the first water washing process. Therefore, the predetermined time in step S8 may be longer or shorter than 90 minutes.

[0084] In this embodiment, the implementation time of the first water washing process refers to the time from the start of step S6 to the end of step S9.

[0085] If the predetermined time has elapsed in step S8, the cleaning operation control unit 46 proceeds to step S9, and if the predetermined time has not elapsed, the cleaning operation control unit 46 continues step S8.

[0086] The washing operation control unit 46 ends the first washing process in step S9.

[0087] The cleaning operation control unit 46 ends the first cleaning operation in step S10.

[0088] In this manner, in the first cleaning operation according to the present embodiment, the first water cleaning process is performed after the first frosting process, thereby cleaning the auxiliary heat exchanger 13a and the main heat exchanger 13b.

[0089] It should be noted that the cleaning operation control unit 46 stops the first cleaning operation when a cleaning operation stop command is received from a remote control or the like, even if the first cleaning operation is in progress.

[0090] Furthermore, the cleaning operation control unit 46 may perform a drying process for drying the auxiliary heat exchanger 13a and the main heat exchanger 13b after performing the process of step S9 in the above flowchart (after the first water-washing process is completed). The drying process may be, for example, a process for drying the auxiliary heat exchanger 13a and the main heat exchanger 13b by continuously blowing air by the indoor fan 14 for a predetermined period of time.

[0091] (6) Features Conventionally, as shown in Patent Document 1, a technical idea has been disclosed in which an indoor heat exchanger is cleaned by performing a frost treatment on the indoor heat exchanger and then thawing the frost formed by the frost treatment.

[0092] However, when cleaning the indoor heat exchanger by performing frost treatment, the frost on the indoor heat exchanger increases the ventilation resistance of the indoor heat exchanger, which reduces the heat exchange efficiency of the indoor heat exchanger. In particular, in order to thoroughly clean the indoor heat exchanger, it is considered that the frost treatment should be performed for a long time, but when cleaning the indoor heat exchanger for a long time, the impact of the reduction in heat exchange efficiency is considered to be large.

[0093] More specifically, if the frost on the indoor heat exchanger increases the ventilation resistance of the indoor heat exchanger and reduces the heat exchange efficiency of the indoor heat exchanger, condensation may not progress. Therefore, even if the unit is operated for a long period of time, it may be difficult to secure a sufficient amount of condensation to wash away the dirt adhering to the indoor heat exchanger.

[0094] Furthermore, the above-mentioned Patent Document 1 discloses an example of an air conditioner in which an indoor fan is driven when performing frost treatment.

[0095] However, when the frosting process is performed for a long time, a large amount of frost adheres to the indoor heat exchanger. Therefore, when the indoor fan is driven during the frosting process, some of the frost may be peeled off from the indoor heat exchanger by the wind of the indoor fan and blown into the air-conditioned space through the air outlet. When frost is blown into the air-conditioned space, it not only gives discomfort to the user, but also may accelerate corrosion of the floor, walls, etc. in the air-conditioned space.

[0096] Furthermore, by performing the frost treatment, the inside of the main casing of the air conditioner indoor unit may be filled with cold air, causing a drop in the temperature near the air outlet of the air conditioner indoor unit. In particular, when performing the frost treatment for a long period of time, condensation may occur near the air outlet, and the condensed water may drip from the air outlet onto the floor or the like of the space to be air-conditioned.

[0097] On the other hand, if the frost treatment time is shortened, it is possible that a sufficient amount of condensation is not secured and sufficient frost does not adhere to the indoor heat exchanger. If the amount of frost that adheres to the indoor heat exchanger is small, less frost is defrosted, and there is a risk that the indoor heat exchanger will not be properly cleaned.

[0098] (6-1) The air conditioner 1 according to this embodiment includes a refrigerant circuit 200 and a control unit 40. The refrigerant circuit 200 includes an indoor heat exchanger 13. When cleaning of the indoor heat exchanger 13 is required, the control unit 40 performs a cleaning operation, which is an operation for cleaning the indoor heat exchanger 13. In the cleaning operation, the control unit 40 performs a frosting process and a water washing process. The frosting process is a process for causing condensation on the surface of the indoor heat exchanger 13 and further frosting the indoor heat exchanger 13. The water washing process is a process for causing condensation on the surface of the indoor heat exchanger 13 after the frosting process and washing the surface of the indoor heat exchanger 13 with the condensed water. In this embodiment, the indoor heat exchanger 13 has an auxiliary heat exchanger 13a and a main heat exchanger 13b.

[0099] In the air conditioner 1 according to this embodiment, the cleaning operation is performed by frosting treatment and water flushing treatment. With this configuration, in the cleaning operation, the indoor heat exchanger can be cleaned while shortening the time for which frosting treatment is performed. Therefore, the amount of frost that adheres to the indoor heat exchanger 13 during the cleaning operation can be suppressed. Therefore, a decrease in the heat exchange efficiency of the indoor heat exchanger 13 during the cleaning operation can be suppressed.

[0100] In addition, during the cleaning operation, the amount of frost adhering to the indoor heat exchanger 13 is suppressed, thereby suppressing the frost from being blown out from the air outlet 15. This maintains the comfort of the user and suppresses corrosion of the floor, walls, etc. in the air-conditioned space.

[0101] In addition, by shortening the time for frost treatment during the cleaning operation, it is possible to suppress the occurrence of condensation near the air outlet 15. This prevents the condensed water from dripping from the air outlet 15 onto the floor or the like of the space to be air-conditioned.

[0102] Furthermore, in the air conditioner 1 according to this embodiment, the cleaning operation is performed by a frosting process and a water washing process that is performed after the frosting process. Therefore, even if the indoor heat exchanger 13 is stained with oil or the like, the indoor heat exchanger 13 can be suitably cleaned.

[0103] (6-2) In the air conditioner 1 according to this embodiment, the frosting process freezes the condensed water by lowering the temperature of the refrigerant flowing through the indoor heat exchanger 13 to a temperature lower than or equal to the temperature at which moisture contained in the indoor air can freeze in the indoor heat exchanger 13. The water washing process causes condensation to occur at a refrigerant temperature higher than the refrigerant temperature during the frosting process.

[0104] (6-3) The air conditioner 1 according to this embodiment further includes an expansion valve 104. The control unit 40 controls the opening degree of the expansion valve 104 to control the temperature of the refrigerant flowing through the indoor heat exchanger 13.

[0105] (6-4) In the air conditioner 1 according to this embodiment, the target evaporation temperature during frost treatment is lower than the target evaporation temperature during water washing treatment.

[0106] (6-5) In the air conditioner 1 according to this embodiment, the amount of humidity dehumidified from the indoor air by the frosting process is less than the amount of humidity dehumidified from the indoor air by the water washing process.

[0107] According to this configuration, it is possible to more reliably prevent a decrease in the heat exchange efficiency of the indoor heat exchanger 13 during frost treatment.

[0108] (6-6) In the air conditioner 1 according to this embodiment, the implementation time of the frosting process is shorter than the implementation time of the water flushing process.

[0109] According to this configuration, it is possible to more reliably prevent a decrease in the heat exchange efficiency of the indoor heat exchanger 13 during frost treatment.

[0110] (6-7) The air conditioner 1 according to this embodiment further includes a compressor 101. The compressor 101 continues to operate while the frosting process and the water washing process are performed.

[0111] In the air conditioner 1 according to this embodiment, while the frosting process and the water flushing process are being performed, the compressor 101 continues to operate. In other words, switching between the frosting process and the water flushing process is performed by adjusting the frequency of the compressor 101 and the opening degree of the expansion valve 104.

[0112] In the air conditioning device 1 according to this embodiment, the time required for the cleaning operation can be shortened.

[0113] (7) Variations The above embodiment can be modified as appropriate, as shown in the following modified examples. Each modified example may be applied in combination with the modified example according to this embodiment or the modified example according to another embodiment, as long as no contradiction occurs. Note that the same reference numerals are used for configurations similar to those of the first embodiment, and detailed descriptions thereof will be omitted.

[0114] (7-1) Variation 1A In the above embodiment, an air conditioner 1 in which no predetermined time is left between the first frosting process and the first flushing process has been described. However, the example of the air conditioner according to the present disclosure is not limited to this, and the air conditioner may be, for example, one in which a predetermined time is left between the first frosting process and the first flushing process. The predetermined time between the first frosting process and the first flushing process is shorter than the implementation time of the frosting process (the time from step S2 to step S5 in FIG. 6), and is, for example, 5 minutes. In addition, it is preferable to drive the indoor fan 14 during the predetermined time between the first frosting process and the first flushing process.

[0115] In the air conditioning apparatus according to this modification, a predetermined time is allowed between the frosting process and the water flushing process, so that the frost adhering to the indoor heat exchanger 13 is naturally thawed. When the frost adhering to the indoor heat exchanger 13 is naturally thawed, the frost dehumidifies the room, and condensed water is generated on the indoor heat exchanger 13. The condensed water cleans the indoor heat exchanger 13. For this reason, in this modification, it is possible to shorten the time required for the water flushing process (the time from step S6 to step S9 in FIG. 6).

[0116] In the air conditioner according to this modification, the time required for the flushing process is shortened, and therefore the air conditioner according to this modification achieves energy savings in the flushing operation.

[0117] Furthermore, the air conditioner according to this modification can suppress any decrease in the heat exchange efficiency of the indoor heat exchanger 13, similar to the air conditioner 1 according to the above embodiment.

[0118] (7-2) Variation 1B In the above embodiment, the first washing operation is described in which the surfaces of the auxiliary heat exchanger 13a and the main heat exchanger 13b are washed by carrying out the first frosting process and the first water washing process. However, the example of the washing operation according to the present disclosure is not limited to this, and for example, the water washing process may be a second water washing process in which the temperature of the refrigerant flowing through the auxiliary heat exchanger 13a is made higher than the refrigerant temperature during the first frosting process to cause condensation. The refrigerant temperature during the second water washing process is preferably controlled to be higher than the freezing temperature and lower than the dew point temperature of the indoor air.

[0119] The cleaning operation according to this modification is carried out by a first frosting process and a second water flushing process. Hereinafter, the cleaning operation according to this modification will be referred to as a second cleaning operation.

[0120] In the second cleaning operation, after frost is formed on the surfaces of the auxiliary heat exchanger 13a and the main heat exchanger 13b by the first frosting process, the surface of the auxiliary heat exchanger 13a is cleaned with condensed water by the second water cleaning process (see FIG. 7). As described above, the area where the frosting process is performed is illustrated with horizontal hatching, and the area where the water cleaning process is performed is illustrated with vertical hatching.

[0121] In the second cleaning operation, the cleaning operation control unit 46 controls the opening of the expansion valve 104, the frequency of the compressor 101, the air volume of the indoor fan 14, and the air volume of the outdoor fan 123 so that the refrigerant temperature detected by the fourth thermistor 108 is higher than the refrigerant temperature detected by the third thermistor 107, and the refrigerant temperature detected by the first thermistor 105 or the third thermistor 107 is higher than the freezing temperature.

[0122] For example, when the refrigerant temperature detected by the third thermistor 107 is lower than the freezing temperature, the control unit 40 performs at least one of increasing the rotation speed of the indoor fan 14, decreasing the frequency of the compressor 101, reducing the amount of pressure reduction by the expansion valve, and decreasing the rotation speed of the outdoor fan.

[0123] In addition, when the refrigerant temperature detected by the third thermistor 107 is higher than the temperature detected by the first thermistor 105, the cleaning operation control unit 46 performs at least one of the following: reducing the rotation speed of the indoor fan 14, increasing the frequency of the compressor 101, reducing the amount of pressure reduction by the expansion valve, and increasing the rotation speed of the outdoor fan.

[0124] Alternatively, if the refrigerant temperature detected by any of the first thermistor 105, the third thermistor 107, and the fourth thermistor 108 is below the freezing temperature, the cleaning operation control unit 46 performs at least one of increasing the airflow of the indoor fan 14, decreasing the frequency of the compressor 101, reducing the amount of pressure reduction by the expansion valve, and reducing the rotation speed of the outdoor fan.

[0125] During the second flushing process in the second flushing operation, the temperature of the refrigerant flowing through the region of the indoor heat exchanger 13 excluding the auxiliary heat exchanger 13a (here, most of the main heat exchanger 13b) is preferably controlled to be higher than the dew point temperature of the indoor air. Although not limited thereto, during the second flushing process in the second flushing operation, the flushing operation control unit 46 controls the auxiliary heat exchanger 13a as an evaporation region and most of the main heat exchanger 13b as a superheat region. As a result, condensation water occurs mainly in the auxiliary heat exchanger 13a.

[0126] In addition, in this modification, the second water flushing process is described as an operation in which the temperature of the refrigerant flowing through the auxiliary heat exchanger 13a is lower than the dew point temperature of the indoor air and higher than the freezing point to generate condensed water, but is not limited thereto. For example, the second water flushing process may be an operation in which the temperature of the refrigerant flowing through the downwind region of the indoor heat exchanger 13, such as the main heat exchanger 13b, is made higher than the refrigerant temperature during the first frosting process to generate condensed water. However, since dirt generally tends to concentrate in the upwind region of the indoor heat exchanger, it is preferable that the second water flushing process is an operation in which the temperature of the refrigerant flowing through the upwind region of the indoor heat exchanger 13 (here, the auxiliary heat exchanger 13a) is made higher than the refrigerant temperature during the first frosting process to generate condensed water.

[0127] The air conditioner according to this modified example is able to suitably clean the indoor heat exchanger 13 even when the atmosphere in the space to be air conditioned is dry.

[0128] Furthermore, the air conditioner according to this modification can suppress any decrease in the heat exchange efficiency of the indoor heat exchanger 13, similar to the air conditioner 1 according to the above embodiment.

[0129] (7-3) Variation 1C In the above embodiment, the first cleaning operation in which the surfaces of the auxiliary heat exchanger 13a and the main heat exchanger 13b are cleaned by performing the first frosting process and the first water washing process has been described. However, the example of the cleaning operation according to the present disclosure is not limited thereto, and for example, the water washing process may be performed by the third water washing process, which is an operation in which the temperature of the refrigerant flowing through a part of the region of the auxiliary heat exchanger 13a is made higher than the refrigerant temperature during the first frosting process to generate condensed water.

[0130] The cleaning operation according to this modification is carried out by a first frosting process and a third water flushing process. Hereinafter, the cleaning operation according to this modification will be referred to as a third cleaning operation.

[0131] In the third cleaning operation, after frost forms on the surfaces of the auxiliary heat exchanger 13a and the main heat exchanger 13b by the first frosting process, the surface of some areas of the auxiliary heat exchanger 13a is cleaned with condensed water by the third water cleaning process (see Figure 8).

[0132] During the third flushing process in the third flushing operation, the temperature of the refrigerant flowing through the area of ​​the indoor heat exchanger 13 excluding a part of the area of ​​the auxiliary heat exchanger 13a is preferably controlled to be higher than the dew point temperature of the indoor air. Although not limited thereto, during the third flushing process in the third flushing operation, the flushing operation control unit 46 controls a part of the area of ​​the auxiliary heat exchanger 13a as an evaporation area and the other area as a superheated area. As a result, condensation water is generated mainly in a part of the area of ​​the auxiliary heat exchanger 13a.

[0133] In addition, in this modification, the third water flushing process is described as an operation to generate condensed water by increasing the temperature of the refrigerant flowing through a part of the region of the auxiliary heat exchanger 13a to a temperature higher than the refrigerant temperature during the first frosting process, but is not limited thereto. For example, the third water flushing process may be an operation to generate condensed water by increasing the temperature of the refrigerant flowing through a downwind region of the indoor heat exchanger 13, such as a part of the region of the main heat exchanger 13b, to a temperature higher than the refrigerant temperature during the first frosting process. However, in consideration of maintaining the aesthetic appearance of the air conditioner by prioritizing cleaning of a region where dirt is noticeable from the user of the air conditioner, it is preferable that the third water flushing process is an operation to generate condensed water by increasing the temperature of the refrigerant flowing through a region that is easily accessible to the user (in this embodiment, a part of the region of the auxiliary heat exchanger 13a, the region near the front panel 11b of the air conditioner) to a temperature higher than the refrigerant temperature during the first frosting process.

[0134] In the air conditioner according to this modified example, the indoor heat exchanger 13 can be suitably cleaned even when the atmosphere in the space to be air conditioned is dry.

[0135] Furthermore, the air conditioner according to this modification can suppress any decrease in the heat exchange efficiency of the indoor heat exchanger 13, similar to the air conditioner 1 according to the above embodiment.

[0136] (7-4) Variation 1D Although the description has been omitted in the above embodiment, the air conditioner may further include a humidification unit (not shown). In this case, the air conditioning indoor unit may have an air outlet of the humidification unit inside the main body casing 11. Alternatively, a humidification unit may be further installed in the air-conditioned space in which the air conditioning indoor unit is installed, and the air conditioning indoor unit may be controlled to perform a cleaning operation in conjunction with the humidification unit.

[0137] The air conditioning apparatus of this modified example can preferably clean the indoor heat exchanger 13 by using moisture obtained from the humidification unit, even when the atmosphere in the space to be air-conditioned is dry.

[0138] Furthermore, the air conditioner according to this modification can suppress any decrease in the heat exchange efficiency of the indoor heat exchanger 13, similar to the air conditioner 1 according to the above embodiment.

[0139] (7-5) Variation 1E Although not described in the above embodiment, it is preferable that the control unit 40 controls the frequency of the compressor 101 and the opening degree of the expansion valve 104 in the first frosting process so that the surface temperature of the indoor heat exchanger 13 becomes equal to or lower than the freezing temperature. The surface temperature of the indoor heat exchanger 13 can be detected, for example, by attaching a second thermistor 106 to the indoor heat exchanger 13. However, the method of detecting the surface temperature of the indoor heat exchanger 13 is not limited to this and can be changed as appropriate.

[0140] The air conditioner according to this modification can suppress a decrease in the heat exchange efficiency of the indoor heat exchanger 13, similar to the air conditioner 1 according to the above embodiment.

[0141] (7-6) Variation 1F In the above embodiment, the air conditioner in which the target evaporation temperature during the frost treatment is lower than the target evaporation temperature during the water washing treatment has been described. However, the example of the air conditioner according to the present disclosure is not limited to this, and the air conditioner may be, for example, one in which the target evaporation temperature during the water washing treatment is not set.

[0142] In the air conditioner according to this modification, a target evaporation temperature is not set during the flushing process. On the other hand, in the air conditioner according to this modification, a lower limit of the evaporation temperature during the flushing process is set. The lower limit of the evaporation temperature during the flushing process is set to a temperature (e.g., 5°C) at which the condensed water generated on the surface of the indoor heat exchanger 13 does not freeze.

[0143] The air conditioner 1 according to this modification, like the air conditioner 1 according to the above embodiment, can suitably clean the indoor heat exchanger 13 while suppressing a decrease in the heat exchange efficiency of the indoor heat exchanger 13.

[0144] (7-7) Variation 1G In the above embodiment, the first cleaning operation in which the surfaces of the auxiliary heat exchanger 13a and the main heat exchanger 13b are cleaned by carrying out the first frosting process and the first water washing process has been described. However, the example of the cleaning operation according to the present disclosure is not limited thereto, and for example, the frosting process may be a second frosting process in which the temperature of the refrigerant flowing through the auxiliary heat exchanger 13a is lowered to a freezing temperature or lower to cause condensed water generated on the surface of the auxiliary heat exchanger 13a to frost.

[0145] The cleaning operation according to this modification is carried out by the second frosting process and the first water washing process. Hereinafter, the cleaning operation according to this modification will be referred to as the fourth cleaning operation.

[0146] In the fourth cleaning operation, after frost is formed on the surface of the auxiliary heat exchanger 13a by the second frosting process, the surfaces of the auxiliary heat exchanger 13a and the main heat exchanger 13b are cleaned with condensed water by the first water cleaning process (see FIG. 9). As described above, the area where the frosting process is performed is illustrated with horizontal hatching, and the area where the water cleaning process is performed is illustrated with vertical hatching.

[0147] In the fourth cleaning operation, the cleaning operation control unit 46 controls the frequency of the compressor 101, the opening of the expansion valve 104, and the rotation speed of the indoor fan 14 so that the temperature of the refrigerant flowing through the auxiliary heat exchanger 13a becomes a temperature below the freezing temperature.

[0148] Specifically, the cleaning operation control unit 46 performs the second frosting process by setting the target evaporation temperature of the auxiliary heat exchanger 13a to -5 to -10°C, stopping the operation of the indoor fan 14, reducing the opening of the expansion valve 104, and controlling the frequency of the compressor 101 to 5 to 10 Hz. However, the above control is only an example and can be changed as appropriate. Therefore, the fourth cleaning operation may be performed by setting the target evaporation temperature of the auxiliary heat exchanger 13a to -5 to -10°C, driving the indoor fan 14 at a low rotation speed, reducing the opening of the expansion valve 104, and controlling the frequency of the compressor 101 to 15 to 25 Hz.

[0149] In the air conditioner according to this modified example, the indoor heat exchanger 13 can be suitably cleaned even when the atmosphere in the space to be air conditioned is dry.

[0150] Furthermore, the air conditioner according to this modification can suppress any decrease in the heat exchange efficiency of the indoor heat exchanger 13, similar to the air conditioner 1 according to the above embodiment.

[0151] (7-8) Variation 1H In the above embodiment, the first cleaning operation is described in which the surfaces of the auxiliary heat exchanger 13a and the main heat exchanger 13b are cleaned by performing the first frosting process and the first water washing process. However, the example of the cleaning operation according to the present disclosure is not limited thereto, and for example, the cleaning operation may be performed by the second frosting process and the second water washing process.

[0152] The cleaning operation according to this modification is carried out by the second frosting process and the second water washing process. Hereinafter, the cleaning operation according to this modification will be referred to as a fifth cleaning operation.

[0153] In the fifth cleaning operation, after frost is formed on the surface of the auxiliary heat exchanger 13a by the second frosting process, the surface of the auxiliary heat exchanger 13a is cleaned with condensed water by the second water cleaning process (see FIG. 10). As described above, the area where the frosting process is performed is illustrated with horizontal hatching, and the area where the water cleaning process is performed is illustrated with vertical hatching.

[0154] In the air conditioner according to this modified example, the indoor heat exchanger 13 can be suitably cleaned even when the atmosphere in the space to be air conditioned is dry.

[0155] Furthermore, the air conditioner according to this modification can suppress any decrease in the heat exchange efficiency of the indoor heat exchanger 13, similar to the air conditioner 1 according to the above embodiment.

[0156] (7-9) Variation 1I In the above embodiment, the first cleaning operation is described in which the surfaces of the auxiliary heat exchanger 13a and the main heat exchanger 13b are cleaned by performing the first frosting process and the first water washing process. However, the example of the cleaning operation according to the present disclosure is not limited thereto, and for example, the cleaning operation may be performed by the second frosting process and the third water washing process (see FIG. 11).

[0157] The cleaning operation according to this modification is carried out by the second frosting process and the third water washing process. Hereinafter, the cleaning operation according to this modification will be referred to as the sixth cleaning operation.

[0158] In the sixth cleaning operation, after frost is formed on the surface of the auxiliary heat exchanger 13a by the second frosting process, the surface of a portion of the area of ​​the auxiliary heat exchanger 13a is cleaned with condensed water by the third water cleaning process (see FIG. 11). As described above, the area where the frosting process is performed is shown by hatching with horizontal lines, and the area where the water cleaning process is performed is shown by hatching with vertical lines.

[0159] In the air conditioner according to this modified example, the indoor heat exchanger 13 can be suitably cleaned even when the atmosphere in the space to be air conditioned is dry.

[0160] Furthermore, the air conditioner according to this modification can suppress any decrease in the heat exchange efficiency of the indoor heat exchanger 13, similar to the air conditioner 1 according to the above embodiment.

[0161] (7-10) Variation 1J In the above embodiment, the first cleaning operation is described in which the surfaces of the auxiliary heat exchanger 13a and the main heat exchanger 13b are cleaned by performing the first frosting process and the first water washing process. However, the example of the cleaning operation according to the present disclosure is not limited to this, and for example, the cleaning operation may be performed by the third frosting process, which causes frost to form in a part of the auxiliary heat exchanger 13a by lowering the temperature of the refrigerant flowing through the part of the auxiliary heat exchanger 13a to a freezing temperature or lower, and the first water washing process (see FIG. 12).

[0162] The cleaning operation according to this modification is carried out by the third frosting process and the first water flushing process. Hereinafter, the cleaning operation according to this modification will be referred to as the seventh cleaning operation.

[0163] In the seventh cleaning operation, after frost is formed on the surface of a portion of the area of ​​the auxiliary heat exchanger 13a by the third frosting process, the auxiliary heat exchanger 13a and the main heat exchanger 13b are cleaned with condensed water by the first water cleaning process (see FIG. 12). As described above, the area where the frosting process is performed is shown by horizontal hatching, and the area where the water cleaning process is performed is shown by vertical hatching.

[0164] In the air conditioner according to this modified example, the indoor heat exchanger 13 can be suitably cleaned even when the atmosphere in the space to be air conditioned is dry.

[0165] Furthermore, the air conditioner according to this modification can suppress any decrease in the heat exchange efficiency of the indoor heat exchanger 13, similar to the air conditioner 1 according to the above embodiment.

[0166] (7-11) Variation 1K In the above embodiment, the first cleaning operation is described in which the surfaces of the auxiliary heat exchanger 13a and the main heat exchanger 13b are cleaned by performing the first frosting process and the first water washing process. However, the example of the cleaning operation according to the present disclosure is not limited thereto, and for example, the cleaning operation may be performed by the third frosting process and the second water washing process (see FIG. 13).

[0167] The cleaning operation according to this modification is carried out by the third frosting process and the second water washing process. Hereinafter, the cleaning operation according to this modification will be referred to as the eighth cleaning operation.

[0168] In the eighth cleaning operation, after frost is formed on the surface of a portion of the area of ​​the auxiliary heat exchanger 13a by the third frosting process, the auxiliary heat exchanger 13a is cleaned with condensed water by the second water cleaning process (see FIG. 13). As described above, the area where the frosting process is performed is shown with horizontal hatching, and the area where the water cleaning process is performed is shown with vertical hatching. In the air conditioner according to this modified example, the indoor heat exchanger 13 can be suitably cleaned even when the atmosphere in the space to be air conditioned is dry.

[0169] Furthermore, the air conditioner according to this modification can suppress any decrease in the heat exchange efficiency of the indoor heat exchanger 13, similar to the air conditioner 1 according to the above embodiment.

[0170] (7-12) Variation 1L In the above embodiment, the first cleaning operation is described in which the surfaces of the auxiliary heat exchanger 13a and the main heat exchanger 13b are cleaned by performing the first frosting process and the first water washing process. However, the example of the cleaning operation according to the present disclosure is not limited thereto, and for example, the cleaning operation may be performed by the third frosting process and the third water washing process (see FIG. 14).

[0171] The cleaning operation according to this modification is carried out by a third frosting process and a third water flushing process. Hereinafter, the cleaning operation according to this modification will be referred to as a ninth cleaning operation.

[0172] In the ninth cleaning operation, after frost is formed on the surface of a portion of the region of the auxiliary heat exchanger 13a by the third frosting process, the surface of the portion of the region of the auxiliary heat exchanger 13a is cleaned with condensed water by the second water cleaning process (see FIG. 14). As described above, the region where the frosting process is performed is shown with horizontal hatching, and the region where the water cleaning process is performed is shown with vertical hatching. In the air conditioner according to this modified example, the indoor heat exchanger 13 can be suitably cleaned even when the atmosphere in the space to be air conditioned is dry.

[0173] Furthermore, the air conditioner according to this modification can suppress any decrease in the heat exchange efficiency of the indoor heat exchanger 13, similar to the air conditioner 1 according to the above embodiment.

[0174] <Other embodiments> Although the embodiments according to the present disclosure have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims.

[0175] The present disclosure is not limited to the above-mentioned embodiments as they are. The present disclosure can be embodied by modifying the components in the implementation stage without departing from the gist of the disclosure. In addition, the present disclosure can form various disclosures by appropriate combinations of multiple components disclosed in the above-mentioned embodiments. For example, some components may be deleted from all components shown in the embodiments. Furthermore, components may be appropriately combined in different embodiments. Therefore, the present embodiment should be considered to be merely an example in all respects and not limiting, and it is intended that any modifications obvious to a person skilled in the art are included in the embodiments. [Explanation of symbols]

[0176] 1. Air conditioning equipment 13 Indoor heat exchanger 40 Control section 42 Cooling operation 44 1st Operation 45 2nd Operation 46 Cleaning operation 47 Frost treatment 48 Washing process 101 Compressor 104 Expansion valve [Prior art documents] [Patent documents]

[0177] [Patent Document 1] JP 2018-189262 A

Claims

1. a refrigerant circuit (200) including an indoor heat exchanger (13), an outdoor heat exchanger (103), and a compressor (101); a control unit (40) that performs a cleaning operation for cleaning the indoor heat exchanger when cleaning of the indoor heat exchanger is required; Equipped with The control unit is In the cleaning operation, a frosting process is performed in which condensation is caused on the surface of the indoor heat exchanger and the indoor heat exchanger is further frosted, and a water washing process is performed in which condensation is caused on the surface of the indoor heat exchanger after the frosting process and the surface of the indoor heat exchanger is washed with the condensed water, The implementation time of the frosting treatment is shorter than the implementation time of the water washing treatment, After the water washing process is completed, the cleaning operation is completed. The water flushing process is a process of operating the compressor in a vapor compression refrigeration cycle in which the outdoor heat exchanger serves as a condenser of the refrigerant and the indoor heat exchanger serves as an evaporator of the refrigerant in the refrigerant circuit. Air conditioning unit (1).

2. The frosting process freezes condensation water by lowering the temperature of the refrigerant flowing through the indoor heat exchanger to a temperature at which moisture contained in the indoor air can freeze in the indoor heat exchanger or lower, The water washing process causes the condensation to occur at a refrigerant temperature higher than the refrigerant temperature during the frost formation process. The air conditioning apparatus according to claim 1.

3. Expansion valve (104) Further equipped with The control unit adjusts the opening degree of the expansion valve to control the temperature of the refrigerant flowing through the indoor heat exchanger.

3. An air conditioning apparatus according to claim 1 or 2.

4. The target evaporation temperature during the frosting treatment is lower than the target evaporation temperature during the water washing treatment. An air-conditioning apparatus according to any one of claims 1 to 3.

5. The amount of moisture removed from the indoor air by the frosting treatment is less than the amount of moisture removed from the indoor air by the water washing treatment. An air-conditioning apparatus according to any one of claims 1 to 4.

6. The compressor is continuously operated during the frost treatment and the water washing treatment. An air-conditioning apparatus according to any one of claims 1 to 5.

7. A predetermined time is allowed to elapse between the frosting process and the water washing process. An air-conditioning apparatus according to any one of claims 1 to 5.

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