Air conditioner

Abstract

An air conditioner (1) is disclosed, comprising a compressor (10), an indoor unit (20A), and a control unit (50), wherein the outdoor unit (10) comprises a compressor (11), and the indoor unit (20A) is connected to the outdoor unit (10) via a refrigerant pipe and comprises an indoor heat exchanger (24A). The control unit (50) can execute a cleaning operation including making the indoor heat exchanger (24A) function as an evaporator to clean the indoor heat exchanger (24A) and a cooling operation including making the indoor heat exchanger (24A) function as an evaporator to perform air conditioning. The control unit (50) comprises a storage unit (51a) for storing an upper limit frequency of the compressor (11) during the cooling operation. The control unit (50) operates the compressor (11) at a frequency higher than the upper limit frequency during the cleaning operation. Thus, the time required for the cleaning operation can be shortened.

Description

Technical Field

[0001] The present disclosure relates to an air conditioner. Background Art

[0002] Patent Document 1 discloses an air conditioner capable of performing a cleaning operation in which an indoor heat exchanger functions as an evaporator and the indoor heat exchanger is cleaned with moisture condensed on the surface of the indoor heat exchanger.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 6743869 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] In order to effectively clean the indoor heat exchanger by the cleaning operation, it is necessary to ensure that the amount of moisture adhering to the surface of the indoor heat exchanger is greater than a predetermined amount. However, it may take a long time for the required amount of moisture to adhere to the surface of the indoor heat exchanger.

[0008] An object of the present disclosure is to provide an air conditioner capable of shortening the time required for a cleaning operation.

[0009] Technical solutions adopted to solve technical problems

[0010] The indoor unit of the air conditioner disclosed in the present invention comprises an outdoor unit, an indoor unit and a control unit, wherein the outdoor unit comprises a compressor, and the indoor unit is connected to the outdoor unit via a refrigerant pipe and comprises an indoor heat exchanger. The control unit is capable of performing a cleaning operation and a cooling operation, wherein the cleaning operation comprises cleaning the indoor heat exchanger by causing the indoor heat exchanger to function as an evaporator, and the cooling operation is air conditioning by causing the indoor heat exchanger to function as an evaporator, and the control unit comprises a storage unit for storing an upper limit frequency of the compressor during the cooling operation, and operates the compressor at a frequency higher than the upper limit frequency during the cleaning operation.

[0011] Thus, the compressor operates at a frequency higher than the upper limit frequency during the cleaning operation, so that a required amount of water condenses or frosts on the surface of the indoor heat exchanger in a short time, thereby shortening the time required for the cleaning operation.

[0012] Alternatively, a plurality of indoor units including a first indoor unit and a second indoor unit may be connected to the outdoor unit via the refrigerant pipe, and the control unit may execute the cleaning operation or the cooling operation in each indoor unit. Thus, the invention can be applied to a multi-type air conditioner.

[0013] Alternatively, the control unit may operate the compressor at a frequency higher than the upper limit frequency when two or more of the indoor units are in the cleaning operation or the cooling operation and one or more of the indoor units are in the cleaning operation. Thus, the time required for the cleaning operation can be shortened when the other indoor units in the multi-connected air conditioner are in the cooling operation.

[0014] Alternatively, when the first indoor unit is in the cleaning operation and the second indoor unit is in the cooling operation, the control unit makes the air volume blown out from the second indoor unit smaller than the air volume instructed by the user. Thus, the temperature of the indoor heat exchanger of the first indoor unit is further reduced, making it easier to more quickly secure the required amount of moisture.

[0015] Alternatively, the control unit may set a threshold temperature of the indoor temperature for blocking the supply of the refrigerant from the outdoor unit to the indoor heat exchanger of the second indoor unit when the first indoor unit is in the cleaning operation and the second indoor unit is in the cooling operation to be higher than the threshold temperature when the cleaning operation is not performed in the first indoor unit. Thus, the temperature of the indoor heat exchanger of the first indoor unit is lowered, making it easier to more quickly secure a required amount of moisture.

[0016] Alternatively, the control unit may operate the compressor at a frequency higher than the upper limit frequency during the cleaning operation when the humidity of the place where the indoor unit is installed is below a predetermined value. Thus, when the humidity is low, it becomes easy to ensure the amount of moisture that condenses or frosts on the indoor heat exchanger.

[0017] Alternatively, the control unit may further execute a heating operation for performing air conditioning by causing the indoor heat exchanger to function as a condenser, and after the cleaning operation in the indoor unit is completed, the heating operation is executed so that the room temperature of the place where the indoor unit is installed becomes greater than a reference value. In this way, the room temperature that has dropped during the cleaning operation can be raised.

[0018] The evaporation temperature of the refrigerant during the cleaning operation may be lower than the evaporation temperature of the refrigerant during the cooling operation. This makes it easier to ensure the amount of moisture that condenses or frosts in the indoor heat exchanger.

[0019] The indoor unit may include a damper capable of opening and closing an air outlet, and the control unit may set the damper to a horizontal position or a maximum air volume position during the cleaning operation. This can suppress the dripping of condensed water from the damper.

[0020] The indoor unit may include a damper capable of opening and closing an air outlet, and the control unit may prohibit a posture change of the damper during the cleaning operation. This can suppress dripping of condensed water from the damper.

[0021] Alternatively, the control unit may operate the compressor at a frequency lower than the upper limit frequency during the cleaning operation of the indoor unit when the humidity of the place where the indoor unit is installed is higher than a predetermined value. Thus, when it is expected that the amount of moisture in the indoor heat exchanger that is condensed or frosted can be ensured, the refrigerant sound and the splashing of dew can be suppressed by reducing the operating frequency of the compressor.

[0022] The control unit may operate the compressor at a frequency not higher than the upper limit frequency when the first indoor unit is in the cleaning operation and the second indoor unit is in the cooling operation. Thus, the refrigerant sound at the location where the second indoor unit is installed can be reduced.

[0023] Alternatively, when the storage unit stores two or more upper limit frequency candidates, the control unit may store one of the upper limit frequency candidates selected from the two or more upper limit frequency candidates as the upper limit frequency in the storage unit. Thus, a suitable upper limit frequency can be selected from a plurality of upper limit frequency candidates as the upper limit frequency.

[0024] Alternatively, the storage unit stores one or more first upper limit frequency candidates and one or more second upper limit frequency candidates as the upper limit frequency candidates, and when the minimum value among the one or more first upper limit frequency candidates is less than the minimum value among the one or more second upper limit frequency candidates, the control unit stores the minimum value among the one or more first upper limit frequency candidates as the upper limit frequency in the storage unit, and operates the compressor at a frequency higher than the upper limit frequency and lower than the minimum value among the one or more second upper limit frequency candidates during the cleaning operation. When there are two upper limit frequency candidates of different properties, the compressor frequency can be set to be lower than all upper limit frequency candidates of the two types during the cooling operation, and the compressor frequency can be set to be higher than the minimum value of the first upper limit frequency candidate but lower than the minimum value of the second upper limit frequency candidate during the cleaning operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural diagram of a multi-split air conditioner according to one embodiment of the present disclosure.

[0026] Figure 2 yes Figure 1 The indoor unit shown is an external view viewed diagonally from below.

[0027] Figure 3 yes Figure 1 The block diagram of the multi-split air conditioner is shown.

[0028] Figure 4 It is a flow chart of the cleaning operation.

[0029] Figure 5 Yes Figure 1 1 is a flowchart for explaining the operation when there is a request for a cleaning operation in an indoor unit in the multi-type air conditioner shown in FIG.

[0030] Figure 6 Yes Figure 1 Flowchart for explaining the operation in the cleaning operation at a frequency exceeding the upper limit frequency in the multi-type air conditioner shown in FIG.

[0031] Figure 7 Yes Figure 1 In the multi-split air conditioner shown Figure 6 A flowchart illustrating the actions after the cleaning operation is completed. DETAILED DESCRIPTION

[0032] (Overall structure)

[0033] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Figure 1 The structure of a multi-type air conditioner 1 according to one embodiment of the present disclosure is shown. Figure 1 As shown, the multi-split air conditioner 1 includes an outdoor unit 10 and three indoor units 20A, 20B, and 20C, and each indoor unit 20A, 20B, and 20C is connected to the outdoor unit 10 via a refrigerant pipe for the refrigerant to pass through. The indoor unit 20A has a heat exchanger 24A in room A and a fan 25A in room A. The indoor unit 20B has a heat exchanger 24B in room B and a fan 25B in room B. The indoor unit 20C has a heat exchanger 24C in room C and a fan 25C in room C. In addition, in the present embodiment, the indoor units are set to three, but the number of indoor units can be set to any number of more than two. In addition, in the following description, the room where the indoor unit 20A is set is called room A, the room where the indoor unit 20B is set is called room B, and the room where the indoor unit 20C is set is called room C.

[0034] The outdoor unit 10 includes a compressor 11, a four-way reversing valve 12, an outdoor heat exchanger 13, an outdoor fan 15, a storage tank 16, and three electric expansion valves EVA, EVB, and EVC. One of the four ports of the four-way reversing valve 12 is connected to the discharge side of the compressor 11, another is connected to one end of the outdoor heat exchanger 13, another is connected to one end of the storage tank 16, and another is connected to one end of the A-room heat exchanger 24A, the B-room heat exchanger 24B, and the C-room heat exchanger 24C via three refrigerant piping connections 18A, 18B, and 18C. The other end of the outdoor heat exchanger 13 is connected to one end of the three electric expansion valves EVA, EVB, and EVC. The other ends of the three electric expansion valves EVA, EVB, and EVC are connected to the other ends of the A-room heat exchanger 24A, the B-room heat exchanger 24B, and the C-room heat exchanger 24C via three refrigerant piping connections 17A, 17B, and 17C, respectively. The other end of the accumulator 16 is connected to the suction side of the compressor 11. A room fan 25A, B room fan 25B, and C room fan 25C are respectively arranged near the A room heat exchanger 24A, the B room heat exchanger 24B, and the C room heat exchanger 24C. The A room fan 25A is driven by an A room fan motor 26A (see Figure 3 The fan 25B in room B and the fan 25C in room C are also driven by indoor fan motors (not shown).

[0035] The compressor 11, the four-way reversing valve 12, the outdoor heat exchanger 13, the electric expansion valves EVA, EVB, EVC, the A-room heat exchanger 24A, the B-room heat exchanger 24B, the C-room heat exchanger 24C, and the receiver 16 are connected by refrigerant piping to form a refrigerant circuit 3. In the refrigerant circuit 3, for example, slightly flammable R32 is used as a refrigerant.

[0036] A discharge pipe temperature sensor 31 is disposed on the discharge side of the compressor 11. In addition, an outdoor heat exchanger temperature sensor 32 for detecting the outdoor heat exchanger temperature is disposed on the outdoor heat exchanger 13, and an outdoor temperature sensor 33 for detecting the outdoor temperature is disposed near the outdoor heat exchanger 13.

[0037] The A room heat exchanger 24A is provided with an A room heat exchanger temperature sensor 45A for detecting the indoor heat exchanger temperature, and an A room temperature sensor 46A for detecting the indoor temperature and an A room humidity sensor 47A for detecting the indoor humidity are arranged near the A room heat exchanger 24A. The B room heat exchanger 24B is provided with a B room heat exchanger temperature sensor 45B for detecting the indoor heat exchanger temperature, and a B room temperature sensor 46B for detecting the indoor temperature and a B room humidity sensor 47B for detecting the indoor humidity are arranged near the B room heat exchanger 24B. In addition, the C room heat exchanger 24C is provided with a C room heat exchanger temperature sensor 45C for detecting the indoor heat exchanger temperature, and a C room temperature sensor 46C for detecting the indoor temperature and a C room humidity sensor 47C for detecting the indoor humidity are arranged near the C room heat exchanger 24C.

[0038] Figure 2 This is a three-dimensional view of the indoor unit 20A viewed from obliquely below. The indoor unit 20A is a ceiling box type (ceiling embedded) indoor unit. In addition, in the present embodiment, all three indoor units 20A, 20B, and 20C are ceiling box type indoor units, but some or all of them may be wall-mounted or floor-standing indoor units.

[0039] like Figure 2 As shown in FIG. 1 , the indoor unit 20A includes a housing body 101, a rectangular plate 102 mounted on the lower side of the housing body 101, and a grille 103 detachably mounted on the plate 102. Figure 2 Although not shown in the figure, the surface of the plate 102 has a light emitting diode (LED), and is provided with a room A display unit 28A (see Figure 3 ).

[0040] In one side of the length direction of the plate 102, a blow-out port 110 is provided along the short side of the plate 102. In addition, a damper 120 is mounted on the plate 102. The damper 120 can be driven by the A chamber damper driving motor 27A (see Figure 3 ) is driven to rotate relative to the plate 120 within a specified angle range, thereby being able to open and close the blow-out port 110. Figure 3 The state where the air outlet 110 is closed by the damper 120 is shown.

[0041] The drain pipe sleeve 107 protrudes from the side wall of the housing body 101. A drain hose (not shown) is connected to the drain pipe sleeve 107 from the outside. In addition, pipe connection parts 105 and 106 protrude from the side wall of the housing body 101. Refrigerant pipes (not shown) are connected to the pipe connection parts 105 and 106 from the outside. Hanging metal fittings 111 to 113 protrude laterally from the housing body 101. In addition, an electrical installation part 108 is arranged near the housing body 101.

[0042] (Control System)

[0043] Next, the control system of the multi-type air conditioner 1 will be described. Figure 3 2 is a block diagram of the air conditioner 1 according to the present embodiment. In the present embodiment, the three indoor units 20A, 20B, and 20C have the same structure, and therefore, the indoor unit 20A will be mainly described here. Figure 3 In FIG. 2 , the indoor units 20B and 20C are shown in simplified form.

[0044] The outdoor unit 10 includes an outdoor control unit 51, which is composed of a microcomputer including a computing device and a storage device, an input-output circuit, etc. The indoor units 20A, 20B, and 20C respectively include indoor control units 52A, 52B, and 52C, which are composed of a microcomputer including a computing device and a storage device, and an input-output circuit, etc. The outdoor control unit 51 and the indoor control unit 52A are connected via a communication line LA, the outdoor control unit 51 and the indoor control unit 52B are connected via a communication line LB, and the outdoor control unit 51 and the indoor control unit 52C are connected via a communication line LC. The outdoor control unit 51 and the three indoor control units 52A, 52B, and 52C communicate via the communication lines LA, LB, and LC, and the outdoor control unit 51 and the indoor control units 52A, 52B, and 52C operate as the control unit 50 of the multi-split air conditioner 1.

[0045] Temperature detection signals from the discharge pipe temperature sensor 31, the outdoor heat exchanger temperature sensor 32, and the outdoor temperature sensor 33 are supplied to the outdoor control unit 51. In addition, the outdoor control unit 51 controls the compressor 11, the four-way reversing valve 12, the outdoor fan motor 14, and the electric expansion valves EVA, EVB, and EVC.

[0046] The detection signals from the room A heat exchanger temperature sensor 45A, the room A temperature sensor 46A, and the room A humidity sensor 47A are supplied to the indoor control unit 52A. In addition, the indoor control unit 52A controls the room A fan motor 26A, the room A damper drive motor 27A, the room A display unit 28A, and the room A communication unit 29A. The room A communication unit 29A communicates wirelessly with a remote controller (hereinafter referred to as "remote controller") not shown in the figure and can be operated by the user. The control unit 50 receives instructions from the remote controller and controls the operation of the air conditioner 1. The remote controller as a part of the air conditioner 1 has a liquid crystal display unit or a light emitting diode (LED), and can notify the user through light, text, graphics, etc. In addition, in addition to the liquid crystal display unit or the light emitting diode or as a substitute for them, the remote controller may also have a speaker that notifies the user through sound. Hereinafter, the room A display unit 28A and the speaker of the remote controller of the room A are sometimes collectively referred to as a notification unit. In addition, a mobile terminal such as a smart phone installed with a control application for the air conditioner can also be used as a remote controller as a part of the air conditioner 1. In this case, the mobile terminal can function as a notification unit.

[0047] In the multi-split air conditioner 1 of this embodiment, the control unit 50 can perform the following cleaning operation in each indoor unit in addition to air conditioning operation including cooling operation and heating operation, and air supply operation to rotate the A room fan 25A, the B room fan 25B and the C room fan 25C.

[0048] In the multi-type air conditioner 1 of the present embodiment, when the indoor unit 20A performs cooling operation, the outdoor control unit 51 switches the four-way switching valve 12 to Figure 1 The compressor 11 starts to operate at the position of the dotted line shown in FIG. 1 . At this time, the outdoor control unit 51 opens the electric expansion valve EVA at a predetermined opening, while the electric expansion valves EVB and EVC are closed. Furthermore, the high-temperature and high-pressure gas refrigerant discharged from the compressor 11 is condensed by heat exchange with the outdoor air in the outdoor heat exchanger 13 acting as a condenser due to the rotation of the outdoor fan 15 by the outdoor control unit 51, and becomes a liquid refrigerant. Next, the liquid refrigerant from the outdoor heat exchanger 13 is decompressed by the electric expansion valve EVA and reaches the A room heat exchanger 24A. The indoor control unit 52A operates the A room fan 25A, whereby the decompressed liquid refrigerant evaporates by heat exchange with the indoor air in the A room heat exchanger 24A acting as an evaporator and becomes a gas refrigerant, and returns to the suction side of the compressor 11. In addition, the indoor control unit 52A moves the damper 120 to a position where the air outlet 110 is opened, whereby the air cooled by the A room heat exchanger 24A is discharged from the air outlet 110.

[0049] On the other hand, when the indoor unit 20A is in heating operation, the outdoor control unit 51 switches the four-way switching valve 2 to Figure 1 The operation of the compressor 11 is started at the position of the solid line shown. At this time, the outdoor control unit 51 opens all the electric expansion valves EVA, EVB, and EVC to a specified opening. Therefore, when the indoor unit 20A is in heating operation, the high-temperature refrigerant also flows into the other indoor units 20B and 20C. This is to prevent the refrigerant from stagnating in the indoor units 20B and 20C and the refrigerant pipes before and after them that are not in heating operation. In addition, the high-temperature and high-pressure gas refrigerant discharged from the compressor 11 is condensed by heat exchange with indoor air in the A room heat exchanger 24A that functions as a condenser due to the indoor control unit 52A operating the A room fan 25A, and becomes a liquid refrigerant. Then, the refrigerant from the A room heat exchanger 24A, the B room heat exchanger 24B, and the C room heat exchanger 24C is reduced in pressure in the electric expansion valves EVA, EVB, and EVC, and then reaches the outdoor heat exchanger 13. Since the outdoor control unit 51 rotates the outdoor fan 15, the decompressed refrigerant evaporates through heat exchange with the outdoor air in the outdoor heat exchanger 13 functioning as an evaporator and becomes a gas refrigerant, and returns to the suction side of the compressor 11. In addition, the indoor control unit 52A moves the damper 120 to a position where the air outlet 110 is opened, whereby the air heated by the A room heat exchanger 24A is discharged from the air outlet 110.

[0050] The control content of the control unit 50 on the outdoor unit 10 and the indoor units 20A, 20B, and 20C is changed by the command from the remote controller. The user can request the multi-type air conditioner 1 to select heating operation and cooling operation, start operation, stop operation, set indoor temperature and air volume, and start and stop cleaning operation by operating the remote controller. The user can choose to set the air volume to a fixed mode or an automatic mode by operating the remote controller. In the fixed mode, the air volume is fixed to a level selected by the user from multiple levels (for example, three levels of "strong wind", "weak wind", and "light wind"). In the automatic mode, the most suitable air volume is automatically selected from multiple levels of air volume according to the difference between the set temperature and the room temperature. In addition, the user can change the posture (position) of the damper 120 by operating the remote controller. In the present embodiment, the damper 120 is in a position to close the air outlet 110 when the indoor unit is stopped, and is in any of a plurality of postures (including a horizontal position and a maximum air volume position) with different degrees of opening of the air outlet 110 during air conditioning operation and cleaning operation. As described later, the posture of the damper 120 of the indoor unit is fixed at the horizontal position or the maximum air volume position during the cleaning operation, but can be changed by operating the remote controller during the air-conditioning operation.

[0051] In this embodiment, the outdoor control unit 51 includes a storage unit 51a. The storage unit 51a stores the upper limit frequency of the compressor 11 during cooling operation. For example, during cooling operation in the indoor unit 20A, the frequency of the compressor 11 changes according to the room temperature of room A, the outdoor temperature, the set temperature, and the air volume. During cooling operation, the control unit 50 does not operate the compressor 11 at a frequency exceeding the upper limit frequency stored in the storage unit 51a.

[0052] In the present embodiment, the control unit 50 selects an upper limit frequency candidate from a plurality of upper limit frequency candidates stored in the storage unit 51a, and stores the selected upper limit frequency candidate in the storage unit 51a as the upper limit frequency of the compressor 11 during cooling operation. In the present embodiment, the upper limit frequency candidates include a first type and a second type. The first type of upper limit frequency candidate has nothing to do with product protection in the present embodiment, for example, it is used to set the temperature of the indoor heat exchanger to a certain value or more so as not to exceed the anti-dew property of the indoor unit (the purpose is to prevent the moisture attached to the indoor heat exchanger from being blown out to the outside of the indoor unit by the wind from the fan), to suppress the sound made when the refrigerant passes through the piping (the purpose is to avoid abnormal sounds), to suppress the generation of sounds when the user requires noise (the purpose is to avoid noise), and to suppress the sound made when the refrigerant passes through the piping during startup for a period of time after startup (the purpose is to avoid abnormal sounds during startup). The second upper limit frequency candidate is related to product protection in this embodiment, for example, for limiting the current current value to protect electrical installation components (the purpose is to protect electrical installation components), for limiting the current discharge pipe temperature to protect the compressor (the purpose is to protect the compressor), for setting the ratio of high pressure to low pressure to below a certain value (the purpose is to protect the compressor), for ensuring the reliability of the compressor at low speed (the purpose is to protect the compressor), for preventing the pressure of the compressor from deviating from the design pressure (the purpose is to protect the compressor), for preventing the current temperature of electrical installation components from exceeding the specified value (the purpose is to protect electrical installation components), proportional to the outdoor temperature (the purpose is to protect electrical installation components when the current value cannot be protected during abnormal voltage, etc.), for ensuring the reliability of the compressor at startup (the purpose is to protect the compressor), etc.

[0053] Each upper limit frequency candidate may be a fixed value corresponding to the capacity of the indoor unit, or a variable value obtained by calculation based on various conditions related to the air conditioner 1. When the upper limit frequency candidate is obtained by calculation in the control unit 50, the latest upper limit frequency candidate is overwritten and stored in the storage unit 51a. As an example, when the upper limit frequency candidate is determined in a manner proportional to the outdoor temperature, the outdoor temperature is periodically detected, and the upper limit frequency candidate is calculated using the detected outdoor temperature as a parameter and overwritten in the storage unit 51a.

[0054] In the present embodiment, the control unit 50 uses the minimum value among one or more first upper limit frequency candidates and one or more second upper limit frequency candidates as the upper limit frequency and stores it in the storage unit 51a. When the minimum value among one or more first upper limit frequency candidates is less than one or more second upper limit frequency candidates, the control unit 50 uses the minimum value among one or more first upper limit frequency candidates as the upper limit frequency and stores it in the storage unit 51a. In the following description, the case where the storage unit 51a stores the minimum value among one or more first upper limit frequency candidates as the upper limit frequency (the minimum value among one or more second upper limit frequency candidates is greater than the upper limit frequency) is described. In addition, in the case where a variable value is included in the upper limit frequency candidate, the upper limit frequency stored in the storage unit 51a sometimes changes during refrigeration operation and cleaning operation.

[0055] In addition, the storage unit 51a stores permission information indicating that the compressor 11 is permitted to operate at a frequency exceeding the upper limit frequency during the cleaning operation or prohibition information indicating that the compressor 11 is prohibited. When the permission information is stored, the control unit 50 can operate the compressor 11 at a frequency exceeding the upper limit frequency during the cleaning operation. On the other hand, when the prohibition information is stored, the control unit 50 operates the compressor 11 only at a frequency below the upper limit frequency during the cleaning operation. The control unit 50 can change the permission information stored in the storage unit 51a to the prohibition information, and change the prohibition information to the permission information based on the user's remote control operation.

[0056] (Cleaning operation)

[0057] Next, refer to Figure 4 The details of the cleaning operation performed by the multi-split air conditioner 1 in this embodiment are described. In addition, in the following description, it is assumed that the cleaning operation is requested for one indoor unit 20A when all indoor units are stopped, and the air conditioning operation and cleaning operation are not requested for the other indoor units 20B and 20C until the cleaning operation is completed.

[0058] First, when the remote controller of the indoor unit 20A is operated to request the indoor unit 20A to perform a cleaning operation, in step S1, the control unit 50 performs the evaporator stage of the cleaning operation. Figure 1The controller 50 drives the A-chamber fan motor 26A to rotate the A-chamber fan 25A at a predetermined rotation speed, and drives the A-chamber damper drive motor 27A to move the damper 120 to a position where the air outlet 110 is open. In addition, the damper 120 may be located at a position where the air outlet 110 is closed. At this time, the controller 50 opens the electric expansion valve EVA to a predetermined opening, while the electric expansion valves EVB and EVC are closed. Thus, the A-chamber heat exchanger 24A functions as an evaporator as in the cooling operation, and the evaporator stage of the cleaning operation begins. When the temperature of the A-chamber heat exchanger 24A is higher than 0°C and below the dew point temperature, moisture in the air begins to condense on the surface of the A-chamber heat exchanger 24A. The condensed water can clean the dirt attached to the surface of the A-chamber heat exchanger 24A. In addition, the temperature of the A-chamber heat exchanger 24A at this time may be below the freezing point, so that the moisture in the air frosts on the surface of the A-chamber heat exchanger 24A. In the present embodiment, the length of the evaporator stage is set to a predetermined time. The length of the evaporator stage may also be the time until the amount of water required for cleaning condenses or frosts on the heat exchanger 24A in room A, which is calculated by the control unit 50 based on environmental conditions (one or more of the indoor temperature and humidity of room A and the outdoor temperature). When the evaporator stage ends, the control unit 50 stops the operation of the compressor 11.

[0059] In the present embodiment, a lower limit temperature (e.g., 10°C) is set in the room temperature of the evaporator stage in which the cleaning operation can be performed. When the room temperature is lower than the lower limit temperature, the controller 50 does not start the evaporator stage, and interrupts the evaporator stage if the evaporator stage is in the process of being performed. This is because the amount of water vapor in the air is very small when the room temperature is very low, and the amount of moisture that can adhere to the surface of the A-chamber heat exchanger 24A is also very small, so it can be considered that the cleaning effect cannot be fully exerted. In addition, a lower limit temperature is also set in the room temperature in which the cooling operation can be performed. In the present embodiment, the lower limit temperature of the room temperature in the evaporator stage in which the cleaning operation can be performed is lower than the lower limit temperature of the room temperature in which the cooling operation can be performed.

[0060] Furthermore, in the present embodiment, in order to promote the attachment of moisture to the surface of the A-chamber heat exchanger 24A, the evaporation temperature of the refrigerant in the evaporator stage of the cleaning operation is lower than the evaporation temperature of the refrigerant in the cooling operation when compared under the same environmental conditions (room temperature, humidity, outdoor temperature) and operating conditions (set temperature, air volume). Furthermore, the lower limit value of the evaporation temperature of the refrigerant in the evaporator stage of the cleaning operation is lower than the lower limit value of the evaporation temperature of the refrigerant in the cooling operation.

[0061] Next, in step S2, the control unit 50 executes the air supply phase of the cleaning operation. Specifically, after step S1, the A-chamber fan motor 26A is continuously driven to rotate the A-chamber fan 25A. And, the position of the damper 120 is maintained at the same position as in step S1. In the air supply phase, since the compressor 11 is stopped, the temperature of the A-chamber heat exchanger 24A is increased compared with the temperature of the A-chamber heat exchanger 24A in the evaporator phase. Moreover, the temperature of the A-chamber heat exchanger 24A usually exceeds the dew point temperature. By rotating the A-chamber fan 25A, the evaporation of the moisture condensed on the A-chamber heat exchanger 24A can be promoted. In this embodiment, the rotation speed of the A-chamber fan 25A and the air supply time (the length of the air supply phase) are fixed to a certain value. In addition, in the air supply phase, if the temperature of the A-chamber heat exchanger 24A is increased compared with the temperature of the A-chamber heat exchanger 24A in the evaporator phase, the compressor 11 may not be stopped.

[0062] In step S3, the control unit 50 executes the condenser stage of the cleaning operation. Specifically, the four-way reversing valve 12 is switched to Figure 1 The controller 50 starts the operation of the compressor 11 at the position of the solid line shown in FIG. 2 . In addition, after step S2, the controller 50 continues to drive the fan motor 26A of room A to rotate the fan 25A of room A at a predetermined speed, and maintains the position of the damper 120 at the same position as in step S1. At this time, the controller 50 opens all the electric expansion valves EVA, EVB, and EVC at predetermined openings. Thus, as in the heating operation, the heat exchanger 24A of room A acts as a condenser, and the condenser phase of the cleaning operation begins. In the condenser phase, the temperature of the heat exchanger 24A of room A rises compared to the temperature of the heat exchanger 24A of room A in the air supply phase. Therefore, the evaporation of the moisture remaining on the surface of the heat exchanger 24A of room A can be further promoted. The length of the condenser phase can also be a predetermined time. When the condenser phase ends, the controller 50 stops the compressor 11 and the fan 25A of room A, and drives the damper drive motor 27A of room A to move the damper 120 to the position where the air outlet 110 is closed. In addition, for example, when the air supply phase of step S2 is made sufficiently long, the condenser phase can be omitted.

[0063] (Action when cleaning operation is required)

[0064] Next, refer to Figure 5 The flowchart of FIG. 1 will explain the operation when a cleaning operation is requested for the indoor unit 20A installed in room A in the multi-type air conditioner 1 of the present embodiment. The following steps are executed by the control unit 50 .

[0065] If the cleaning operation is requested in the indoor unit 20A, the control unit 50 determines in step S11 whether at least one of the indoor unit 20B installed in room B and the indoor unit 20C installed in room C is in air conditioning operation. At the time when the cleaning operation is requested, the indoor unit 20A may be performing air conditioning operation or may not be performing any operation. In the following description, the situation in which the indoor units 20B and 20C are in the cleaning operation or the air supply operation is omitted.

[0066] When this condition is satisfied (S11: YES), the process proceeds to step S12. In step S12, the control unit 50 determines whether at least one of the indoor units 20B and 20C is in the heating operation.

[0067] If the condition is satisfied (S12: Yes), the process proceeds to step S13. The following description assumes that the indoor unit 20C is in a dormant state and is not operating, and only the indoor unit 20B is in heating operation. In step S13, the control unit 50 continues the heating operation in the indoor unit 20B. In addition, the control unit 50 uses the notification unit of the indoor unit 20A of room A to notify the user through display or sound that "the cleaning operation cannot be performed due to a conflict with other rooms."

[0068] If the condition of step S12 is not met (S12: No), proceed to step S14. As described above, in the present embodiment, the situation where the indoor units other than room A are in the cleaning operation or the air supply operation is omitted. Therefore, in this case, one or both of the indoor units 20B and 20C are in the cooling operation. In the following, it is assumed that the indoor unit 20C is in the dormant state and is not operating, and only the indoor unit 20B is in the cooling operation for explanation. In step S14, the control unit 50 determines which of the permission information and the prohibition information is stored in the storage unit 51a. And, if the permission information is stored (S14: Yes), proceed to step S15. In step S15, the control unit 50 determines whether the humidity detected by the humidity sensor 47A of room A is below the specified value. And, if this condition is met (S15: Yes), proceed to step S17.

[0069] In step S17, the control unit 50 starts the cleaning operation in the indoor unit 20A. The frequency of the compressor 11 in the evaporator stage of the cleaning operation started in step S17 is higher than the upper limit frequency of the compressor 11 during the cooling operation stored in the storage unit 51a, and is less than the minimum value of one or more second upper limit frequency candidates. In addition, the control unit 50 moves the damper 120 of the indoor unit 20A to a horizontal position or a maximum air volume position. In addition, the control unit 50 stores the room temperature detected by the room A temperature sensor 46A at that time point in the storage unit 51a. The control unit 50 continues the cooling operation being performed in the indoor unit 20B without interruption. Then, the cleaning operation in the indoor unit 20A is transferred to Figure 4 In addition, if the cooling operation of room B is not completed at the time when the condenser phase of the cleaning operation in the indoor unit 20A starts, one of the preset ones is executed instead of the other.

[0070] Return to the judgment of step S14, and if prohibition information is stored (S14: No), proceed to step S16. In step S16, the control unit 50 starts the cleaning operation in the indoor unit 20A. The frequency of the compressor 11 in the evaporator stage of the cleaning operation started in step S16 is less than the upper limit frequency of the compressor 11 during the cooling operation stored in the storage unit 51a. At this time, the control unit 50 moves the damper 120 of the indoor unit 20A to a specified position. In addition, the control unit 50 continues the cooling operation being performed in the indoor unit 20B without interruption. In addition, when the conditions of step S15 are not met (S15: No), the processing of step S16 is also performed.

[0071] If the condition of step S11 is not met (S11: No), the process proceeds to step S14 without passing through step S12. The following process is the same as the process proceeds to step S14 via step S12, except that the cooling operation in the indoor unit 20B is not continued.

[0072] (Actions during cleaning operation in room A)

[0073] Next, refer to Figure 6 The flowchart of FIG. 1 illustrates the action (S17) in the evaporator stage of the cleaning operation in which the compressor 11 is operated at a frequency exceeding the upper limit frequency in the multi-type air conditioner 1 of the present embodiment. The following steps are executed by the control unit 50. In addition, in the following description, it is assumed that the indoor unit 20B is in cooling operation at the beginning of step S17, but it is assumed that the indoor unit 20C is not in cooling operation.

[0074] First, in step S31, the control unit 50 determines whether the air volume setting of the indoor unit 20B is in a fixed mode or an automatic mode. When it is in the fixed mode (S31: Yes), proceed to step S33. When it is in the automatic mode (S31: No), in step S32, the controller 50 derives the most suitable air volume level (any one of "strong wind", "weak wind" or "light breeze") based on the set temperature and the room temperature detected by the B room temperature sensor 46B. In step S33, the control unit 50 reduces the air volume in the fixed mode set by the user for the indoor unit 20B or the air volume in the automatic mode derived in step S32 by one level. In addition, Figure 6 In the flowchart, when step S33 is executed for the second time or later, if in fixed mode, the air volume is further reduced only when the user operates the remote control to reduce the air volume after the last step S33, and if in automatic mode, the air volume is further reduced only when the air volume exported (S32) before step S33 becomes smaller than the air volume exported before.

[0075] Next, in step S34, the control unit 50 obtains the thermal shutdown temperature of the indoor unit 20B. Here, the "thermal shutdown temperature" refers to the threshold temperature of the indoor temperature that blocks the supply of refrigerant from the outdoor unit 10 to the B room heat exchanger 24B of the indoor unit 20B (closing the electric expansion valve EVB) when the cleaning operation in the indoor unit 20A is not in progress and the indoor unit 20B is in cooling operation. The thermal shutdown temperature can also be a value that is a specified temperature (for example, 1°C) lower than the set temperature. And, in step S35, the control unit 50 determines whether the room temperature of room B detected by the B room temperature sensor 46B is below the temperature that is a specified temperature (for example, 2°C) higher than the thermal shutdown temperature.

[0076] When the condition is met (S35: Yes), in step S36, the control unit 50 closes the electric expansion valve EVB. When the condition is not met (S35: No), the process proceeds to step S37 without passing through step S36. In step S37, the control unit 50 determines whether the electric expansion valve EVB is closed. When it is closed (S37: Yes), in step S38, the control unit 50 determines whether the room temperature of room B detected by the room B temperature sensor 46B is above the thermal opening temperature. Here, the "thermal opening temperature" refers to the threshold temperature of the indoor temperature for starting the supply of refrigerant from the outdoor unit 10 to the room B heat exchanger 24B of the indoor unit 20B (opening the electric expansion valve EVB). The thermal opening temperature may also be a value that is a specified temperature (e.g., 4°C) higher than the thermal shutdown temperature.

[0077] If the condition is met (S38: Yes), the control unit 50 opens the electric expansion valve EVB in step S39. If the condition is not met (S38: No), the process proceeds to step S40 without passing through step S39. In addition, if the electric expansion valve EVB is opened in step S37 (S37: No), the process also proceeds to step S40.

[0078] In step S40, the control unit 50 determines whether there is an instruction from the remote controller to change the posture of the damper 120 of the indoor unit 20A. And, if there is an instruction (S40: Yes), proceed to step S41. In step S41, the control unit 50 invalidates the posture change instruction of the damper 120 received from the remote controller. In detail, when the control unit 50 receives the posture change instruction, if it is confirmed that the indoor unit 20A is in the cleaning operation at this time and the storage unit 51a stores the permission information, it does not output the drive command to the A room damper drive motor 27A when receiving the posture change instruction. If step S41 ends, return to step S31. If there is no posture change instruction of the damper 120 (S40: Yes), return to step S31 without passing through step S41.

[0079] Figure 6 The processing shown is continued until the evaporator stage ends. When the air supply stage is entered, the air volume of the indoor unit 20B reduced in step S33 is restored to the original value, and the threshold temperature (S35) of the indoor temperature related to the thermal shutdown of the indoor unit 20B is restored to the normal value. In addition, when a predetermined time has passed after the end of the evaporator stage, the posture of the damper 20 of the indoor unit 20A can be changed.

[0080] (Action after the cleaning operation of room A is completed)

[0081] Next, refer to Figure 7 The flowchart of the multi-split air conditioner 1 of the present embodiment describes the operation after the cleaning operation of step S17 is completed. The following steps are executed by the control unit 50. In addition, the processing described below is performed after the condenser stage of the cleaning operation is completed, but it can also be started immediately after the evaporator stage is completed, and it can also be started immediately after the air supply stage is completed.

[0082] In step S51, the control unit 50 repeatedly determines whether the cooling operation in the indoor unit 20B is finished until this condition is satisfied. If it is finished (S51: Yes), the process proceeds to step S52. In step S52, the control unit 50 determines whether the room temperature detected by the room A temperature sensor 46A at this time point is lower than the room temperature of room A stored in the storage unit 51a when the cleaning operation starts. And if this condition is satisfied (S52: Yes), the process proceeds to step S53, and the control unit 50 starts the heating operation of the indoor unit 20A.

[0083] In step S54, the control unit 50 repeatedly determines whether the room temperature detected by the room A temperature sensor 46A at this time point is higher than the room A room temperature stored in the storage unit 51a at the start of the cleaning operation until this condition is satisfied. If this condition is satisfied (S54: Yes), the control unit 50 proceeds to step S55 and ends the heating operation of the indoor unit 20A.

[0084] (Effects of Embodiments)

[0085] As described above, in the present embodiment, during the cleaning operation (S17) that satisfies the prescribed conditions, the compressor 11 is operated at a frequency higher than the upper limit frequency during the cooling operation. Therefore, compared with the case where the compressor 11 is operated at a frequency below the upper limit frequency, the temperature of the A room heat exchanger 24A of the indoor unit 20A during the cleaning operation can be set to a temperature far lower than the dew point temperature. Therefore, the amount of water required for the cleaning operation condenses or frosts in the A room heat exchanger 24A in a short time, thereby shortening the time required for the cleaning operation. In addition, when other indoor units in the multi-connected air conditioner 1 perform cooling operation, the time required for the cleaning operation can also be shortened.

[0086] In addition, in the present embodiment, the air volume blown out from the indoor unit 20B during the cleaning operation in the indoor unit 20A is set to be smaller than the air volume instructed by the user in the fixed mode and the air volume derived in the automatic mode (S33), so that the temperature of the A room heat exchanger 24A of the indoor unit 20A can be lowered compared to the case where the air volume is not reduced. Therefore, it becomes easy to more quickly secure the amount of moisture required for the cleaning operation in the A room heat exchanger 24A of the indoor unit 20A. In addition, it is possible to suppress an excessive decrease in the room temperature of the B room during the cleaning operation in the indoor unit 20A.

[0087] In addition, in the present embodiment, the threshold temperature at which the electric expansion valve EVB is closed is set higher than the normal thermal shutdown temperature (S35), so that the temperature of the A room heat exchanger 24A of the indoor unit 20A can be lowered compared to the case where the threshold temperature and the normal thermal shutdown temperature are the same. Therefore, it becomes easy to more quickly secure the required amount of moisture in the A room heat exchanger 24A of the indoor unit 20A.

[0088] In addition, when the humidity detected by the room A humidity sensor 47A is below the specified value (S15), it becomes easy to ensure the amount of moisture condensed or frosted in the room A heat exchanger 24A by setting the compressor frequency during the cleaning operation (S17) to be higher than the upper limit frequency during the cooling operation.

[0089] In addition, in the present embodiment, the heating operation is performed after the cleaning operation in the indoor unit 20A is completed so that the room temperature of room A becomes higher than the room temperature at the start of the cleaning operation (S53, S54, S55). Therefore, even if the compressor 11 is operated at a high frequency during the cleaning operation and the room temperature of room A is greatly reduced, the room temperature can be restored immediately.

[0090] In addition, in this embodiment, the evaporation temperature of the refrigerant during the cleaning operation is lower than the evaporation temperature of the refrigerant during the cooling operation. Therefore, it becomes easy to ensure the amount of moisture condensed or frosted in the A room heat exchanger 24A during the cleaning operation of the indoor unit 20A.

[0091] In addition, in the present embodiment, the damper 120 is set to a horizontal position or a maximum air volume position during the washing operation. When the damper 120 is maintained in a horizontal position, water drops are difficult to drip from the damper 120. When the damper 120 is maintained in a maximum air volume position, the flow of air passing near the damper 120 is difficult to be disturbed, and even if the damper 120 becomes low temperature, water drops are difficult to adhere. In this way, in the present embodiment, the dripping of condensed water from the damper 120 can be suppressed.

[0092] Furthermore, in the present embodiment, the change in the posture of the damper 120 is prohibited during the washing operation ( S41 ), so that the dripping of condensed water from the damper 120 can be suppressed.

[0093] In addition, in the present embodiment, even if the indoor unit 20A is in the cleaning operation and the indoor unit 20B is in the cooling operation, as long as the humidity detected by the room A humidity sensor 47A is higher than the predetermined value (S15), the compressor frequency during the cleaning operation (S16) is set to be lower than the upper limit frequency during the cooling operation. In this way, the refrigerant sound and the splashing of dew can be suppressed while the amount of moisture adhering to the room A heat exchanger 24A is expected to be ensured.

[0094] In addition, in the present embodiment, even if the indoor unit 20A is in the cleaning operation and the indoor unit 20B is in the cooling operation, when the prescribed conditions such as prohibiting operation at a frequency exceeding the upper limit frequency are met, the compressor 11 is operated at a frequency below the upper limit frequency (S14), thereby reducing the refrigerant sound in the place where the indoor unit 20B is installed.

[0095] Furthermore, in the present embodiment, an appropriate value (usually the minimum value) can be selected as the upper limit frequency from among a plurality of upper limit frequency candidates.

[0096] In addition, in this embodiment, when the minimum value among one or more first upper limit frequency candidates is less than the minimum value among one or more second upper limit frequency candidates, the minimum value among one or more first upper limit frequency candidates is set as the upper limit frequency, so that the compressor frequency can be set to less than the two upper limit frequency candidates during the cooling operation (S17). And, during the cleaning operation, the compressor frequency is set to exceed the minimum value of the first upper limit frequency candidate but less than the minimum value of the second upper limit frequency candidate, so that the time required for the cleaning operation can be shortened while achieving product protection.

[0097] (Variation Example)

[0098] In the above-mentioned embodiment, the air conditioner of the present invention is described by taking a multi-split air conditioner as an example, however, the air conditioner of the present invention is applicable not only to the multi-split air conditioner, but also to a duplex air conditioner in which an outdoor unit and an indoor unit are connected by a refrigerant pipe. In this case, in the above-mentioned embodiment, the judgment and processing related to the indoor units of other rooms can be omitted. In addition, the air conditioner of the present invention can also be applied to the case of performing a cleaning operation in more than two indoor units in a multi-split air conditioner. In the above-mentioned embodiment, the upper limit frequency is selected from a plurality of upper limit frequency candidates, however, the storage unit 51a may store one upper limit frequency instead of a plurality of upper limit frequency candidates.

[0099] Furthermore, as another variation, in the above embodiment, it is required that Figure 5 The operation during the cleaning operation in the indoor unit 20A shown in FIG. 1 can be performed from step S14, and steps S11, S12, and S13 can be omitted. In this case, if the indoor unit 20B of room B is in the heating operation, the heating operation is stopped in steps S16 and S17. As another modified example, steps S14, S15, and S16 can also be omitted.

[0100] In addition, as another variation, the room temperature of room A at the time point when the cleaning operation in the indoor unit 20A is required may not be stored in the storage unit 51a, but the specified temperature may be pre-stored in the storage unit 51a. In this case, in step S52, it is judged whether the room temperature detected by the room temperature sensor 46A at this time point is lower than the specified temperature stored in the storage unit 51a, and in step S54, it is repeatedly judged whether the room temperature detected by the room temperature sensor 46A at this time point is higher than the specified temperature stored in the storage unit 51a. As another variation, the storage unit 51a may not store a certain temperature, but perform heating operation until the room temperature of room A reaches a temperature higher than the room temperature at the time point when the cleaning operation ends by a specified temperature. In this case, step S52 is omitted, and in step S54, it is repeatedly judged whether the room temperature detected by the room temperature sensor 46A at this time point is higher than the temperature obtained by adding the specified temperature to the room temperature at the time point when the cleaning operation ends. In addition, the above-mentioned multiple variations can also be appropriately combined.

[0101] Although the embodiments have been described above, it should be understood that various changes in form and details can be made without departing from the spirit and scope of the claims.

[0102] (Explanation of symbols)

[0103] 3. Refrigerant circuit;

[0104] 10 outdoor units;

[0105] 11. Compressor;

[0106] 12 four-way reversing valve;

[0107] 13 outdoor heat exchanger;

[0108] 16 storage tanks;

[0109] 17A, 17B, 17C refrigerant pipe connection parts;

[0110] 18A, 18B, 18C refrigerant pipe connection parts;

[0111] 20A, 20B, 20C indoor units;

[0112] 24A A chamber heat exchanger;

[0113] 24B B chamber heat exchanger;

[0114] 24C C chamber heat exchanger;

[0115] 25A fan for room A;

[0116] 25B B room fan;

[0117] 25C C room fan;

[0118] 31 discharge pipe temperature sensor;

[0119] 32 outdoor heat exchanger temperature sensor;

[0120] 33 outdoor temperature sensor;

[0121] 45A A chamber heat exchanger temperature sensor;

[0122] 45B B chamber heat exchanger temperature sensor;

[0123] 45C C chamber heat exchanger temperature sensor;

[0124] 46A A chamber temperature sensor;

[0125] 46B B chamber temperature sensor;

[0126] 46C C chamber temperature sensor;

[0127] EVA, EVB, EVC electric expansion valve.

Claims

1. An air conditioner, characterized in that: include: an outdoor unit, the outdoor unit comprising a compressor; an indoor unit connected to the outdoor unit via a refrigerant pipe and including an indoor heat exchanger; as well as Control Department, The control unit is capable of executing a cleaning operation and a cooling operation, wherein the cleaning operation includes cleaning the indoor heat exchanger by causing the indoor heat exchanger to function as an evaporator, and the cooling operation includes air conditioning by causing the indoor heat exchanger to function as an evaporator. The control unit includes a storage unit that stores an upper limit frequency of the compressor during the cooling operation. The control unit operates the compressor at a frequency higher than the upper limit frequency during the cleaning operation. The plurality of indoor units including the first indoor unit and the second indoor unit are connected to the outdoor unit via the refrigerant pipe, and the control unit can execute the cleaning operation or the cooling operation in each indoor unit. The control unit makes a threshold temperature of the indoor temperature for blocking the supply of refrigerant from the outdoor unit to the indoor heat exchanger of the second indoor unit when the first indoor unit is in the cleaning operation and the second indoor unit is in the cooling operation higher than the threshold temperature when the first indoor unit is not performing the cleaning operation.

2. The air conditioner according to claim 1, characterized in that When two or more of the indoor units are in the cleaning operation or the cooling operation and one or more of the indoor units is in the cleaning operation, the control unit operates the compressor at a frequency higher than the upper limit frequency.

3. The air conditioner according to claim 1, characterized in that The control unit operates the compressor at a frequency higher than the upper limit frequency during the cleaning operation when humidity of a location where the indoor unit is installed is equal to or lower than a predetermined value.

4. The air conditioner according to claim 1, wherein: The control unit can also execute a heating operation for performing air conditioning by causing the indoor heat exchanger to function as a condenser. After the cleaning operation in the indoor unit is completed, the heating operation is performed so that the room temperature of the place where the indoor unit is installed reaches a reference value or more.

5. The air conditioner according to claim 1, wherein: The evaporation temperature of the refrigerant during the cleaning operation is lower than the evaporation temperature of the refrigerant during the cooling operation.

6. The air conditioner according to claim 1, wherein: The indoor unit includes a damper capable of opening and closing an air outlet. The control unit sets the damper to a horizontal position or a maximum air volume position during the washing operation.

7. The air conditioner according to claim 1, wherein: The indoor unit includes a damper capable of opening and closing an air outlet. The control unit prohibits the damper from changing its posture during the washing operation.

8. The air conditioner according to claim 1, wherein: The control unit operates the compressor at a frequency equal to or lower than the upper limit frequency during the cleaning operation of the indoor unit when the humidity of the location where the indoor unit is installed is equal to or higher than a predetermined value.

9. The air conditioner according to claim 1 or 2, characterized in that: When the first indoor unit is in the cleaning operation and the second indoor unit is in the cooling operation, if a predetermined condition is satisfied, the control unit operates the compressor at a frequency equal to or lower than the upper limit frequency.

10. The air conditioner according to claim 1, wherein: When the storage unit stores two or more upper limit frequency candidates, the control unit stores one of the upper limit frequency candidates selected from the two or more upper limit frequency candidates in the storage unit as the upper limit frequency.

11. The air conditioner according to claim 10, wherein: The storage unit stores one or more first upper limit frequency candidates and one or more second upper limit frequency candidates as the upper limit frequency candidates. When the minimum value among the one or more first upper limit frequency candidates is smaller than the minimum value among the one or more second upper limit frequency candidates, the control unit stores the minimum value among the one or more first upper-limit frequency candidates as the upper-limit frequency in the storage unit, During the cleaning operation, the compressor is operated at a frequency that is higher than the upper limit frequency and is equal to or lower than the minimum value among the one or more second upper limit frequency candidates.

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