air conditioner

Abstract

To provide an air conditioner which reduces humidity return generated from an indoor heat exchanger in a cleaning operation.SOLUTION: In an air conditioner which performs a cleaning operation for switching to a drying operation for cleaning, when it is determined that a room temperature detected by a temperature sensor 41 has become equal to or lower than a predetermined operation switching temperature during execution of a cooling operation for cleaning, an indoor control part 40 can control a dehumidification operation for cleaning in which one of a first indoor heat exchanger 32a and a second indoor heat exchanger 32b serves as a condenser and the other serves as an evaporator by throttling a dehumidification valve 36. After finishing the cooling operation for cleaning, the indoor control part 40 performs a dehumidification operation for cleaning by using one heat exchanger as the condenser and the other as the evaporator, and when the dehumidification operation for cleaning of the one heat exchanger is finished, it performs the drying operation for cleaning.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an air conditioner capable of performing a cleaning operation for cleaning an indoor heat exchanger in an indoor unit.

Background Art

[0002] Conventionally, in this type of device, a cleaning operation is performed in which dew condensation water is generated on the surface of an indoor heat exchanger in an indoor unit installed indoors by a cleaning cooling operation in which the indoor heat exchanger functions as an evaporator, and the dust adhering to the surface of the indoor heat exchanger is washed away using the dew condensation water. (For example, Patent Document 1)

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Patent Document 1 cools an indoor heat exchanger to a temperature below the dew point temperature by a cleaning cooling operation, generates dew condensation water on the surface of the indoor heat exchanger, and then performs a cleaning drying operation to dry the dew condensation water adhering to the surface of the indoor heat exchanger. However, since the dew condensation water adhering to the indoor heat exchanger is suddenly discharged into the room as moisture, the humidity in the room rapidly increases, and if there is a person in the room, it will cause discomfort.

Means for Solving the Problems

[0005] The air conditioner according to the present invention includes a refrigerant circuit through which a refrigerant circulates, a compressor with a variable rotational speed provided in the refrigerant circuit, an outdoor heat exchanger provided in the refrigerant circuit for exchanging heat with outdoor air, an expansion valve provided in the refrigerant circuit for reducing the pressure of the refrigerant, a first indoor heat exchanger provided in the refrigerant circuit for exchanging heat with indoor air, a second indoor heat exchanger provided in the refrigerant circuit for exchanging heat with indoor air, a dehumidifying valve provided between the first indoor heat exchanger and the second indoor heat exchanger capable of reducing the pressure of the refrigerant by throttling the valve, a switching valve provided in the refrigerant circuit for changing the direction of flow of the refrigerant, a temperature sensor for detecting room temperature, a cleaning cooling operation for cleaning the first indoor heat exchanger and the second indoor heat exchanger by condensation, and a refrigerant flowing through the refrigerant circuit in the opposite direction to the cleaning cooling operation. In an air conditioner that performs a cleaning operation, the control unit switches the switching valve to control a cleaning drying operation that raises the room temperature by heating the first indoor heat exchanger and the second indoor heat exchanger to a high temperature, and when the control unit determines that the room temperature detected by the temperature sensor has fallen below a predetermined operating switching temperature during the cleaning cooling operation, the control unit can control a cleaning dehumidification operation in which one of the heat exchangers, the first indoor heat exchanger and the second indoor heat exchanger, is used as a condenser and the other as an evaporator by throttling the dehumidification valve, and after the cleaning cooling operation is completed, the control unit performs the cleaning dehumidification operation with one of the heat exchangers as a condenser and the other as an evaporator, and after the cleaning dehumidification operation of one of the heat exchangers is completed, the cleaning drying operation is performed.

[0006] Furthermore, claim 2 provides a dehumidification feasibility determination means for determining whether or not to perform the cleaning dehumidification operation, and if the dehumidification feasibility determination means determines that it is not necessary to perform the cleaning dehumidification operation, the control unit will not perform the cleaning dehumidification operation after the cleaning cooling operation is completed, and will instead perform the cleaning drying operation.

[0007] Furthermore, in claim 3, a humidity sensor is provided to detect the humidity in the room, and the dehumidification feasibility determination means determines that if the humidity detected by the humidity sensor is below a predetermined humidity when the cleaning cooling operation is completed, it is not necessary to perform the cleaning dehumidification operation.

[0008] Furthermore, in claim 4, the indoor heat exchanger is provided with a heat exchanger temperature sensor, and the dehumidification feasibility determination means determines that, at the end of the cleaning cooling operation, if the humidity estimated from the indoor temperature detected by the temperature sensor and the heat exchanger temperature detected by the heat exchanger temperature sensor is within a range of a predetermined humidity or less, it is not necessary to perform the cleaning dehumidification operation.

[0009] Furthermore, claim 5 provides an indoor unit having the first indoor heat exchanger and the second indoor heat exchanger inside, and the indoor unit is equipped with a motion sensor that detects whether or not there is a person in the room, and the dehumidification feasibility determination means determines that if the motion sensor detects that there is no person in the room at the end of the cleaning cooling operation, it is not necessary to perform the cleaning dehumidification operation. [Effects of the Invention]

[0010] According to this invention, during the cleaning operation, condensation water adhering to one of the first or second indoor heat exchangers is dried with a cleaning dehumidification operation, and once the drying of one is complete, the other indoor heat exchanger is dried with a cleaning drying operation. This reduces the amount of moisture returning to the room compared to when both indoor heat exchangers are dried simultaneously, preventing discomfort for people inside the room. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram of an air conditioner in one embodiment of the present invention. [Figure 2] This is a control block diagram of the same embodiment. [Figure 3] This is a flowchart illustrating the control details for the heating operation for cleaning in the same embodiment. [Figure 4]This is a flowchart illustrating the control details for the cooling operation, dehumidification operation, and drying operation for washing in this embodiment. [Figure 5] Calculation table for estimating humidity from room temperature and heat exchanger temperature [Modes for carrying out the invention]

[0012] One embodiment of the present invention is described below with reference to the attached diagram.

[0013] Figure 1 shows an air conditioner 10 (air conditioned unit) equipped with a refrigerant circuit 11 through which refrigerant flows. The air conditioner 10 has the function of performing cooling operation to cool the indoor R and heating operation to heat the indoor R. The refrigerant circuit 11 includes an outdoor unit 20 located outside Ou and an indoor unit 30 located inside R. Unless otherwise specified, the direction of refrigerant circulation is based on the cooling operation.

[0014] The outdoor unit 20 includes a switching valve 21 that switches the direction of refrigerant flow during cooling and heating operations, a compressor 22 through which the refrigerant that has passed through the switching valve 21 flows and compresses the refrigerant, an outdoor heat exchanger 23 through which the refrigerant that has been compressed in the compressor 22 and has become high temperature and high pressure flows, a propeller fan 24 that sends outdoor air toward the outdoor heat exchanger 23, and an expansion valve 25 that reduces the pressure of the refrigerant that has passed through the outdoor heat exchanger 23.

[0015] The indoor unit 30 is mounted on the wall Wa in the room R. The indoor unit 30 includes an indoor fan 31 that takes in air from the room and blows air into the room, an indoor heat exchanger 32 that exchanges heat with the indoor air taken in by the indoor fan 31, and a case 33 that houses the indoor fan 31, the indoor heat exchanger 32, and the dehumidifying valve 36.

[0016] Here, the indoor heat exchanger 32 is composed of a first indoor heat exchanger 32a and a second indoor heat exchanger 32b. The first indoor heat exchanger 32a is one of the heat exchangers of the indoor heat exchanger 32, and is a heat exchanger arranged on the upstream side in the refrigerant flow during the cooling operation. Further, an expansion valve 25 is arranged upstream of the first indoor heat exchanger 32a. The second indoor heat exchanger 32b is one of the heat exchangers of the indoor heat exchanger 32, and is a heat exchanger arranged on the downstream side in the refrigerant flow during the cooling operation. Further, a switching valve 21 is arranged downstream of the second indoor heat exchanger 32b.

[0017] The case 33 has an air outlet 33a that serves as an outlet for the air sent out by the indoor fan 31. At the air outlet 33a, left and right louvers 34 for adjusting the left and right directions of the blown air and up and down louvers 35 for adjusting the up and down directions of the blown air are arranged.

[0018] The dehumidification valve 36 is provided between the first indoor heat exchanger 32a and the second indoor heat exchanger 32b, and it is possible to depressurize the refrigerant by throttling the valve, and it is also possible not to depressurize the refrigerant by fully opening the valve.

[0019] Therefore, when the dehumidification valve 36 is in the fully open state, it is possible to make the first indoor heat exchanger 32a and the second indoor heat exchanger 32b function as an integrated indoor heat exchanger 32.

[0020] The cooling operation will be described. The refrigerant heated to a high temperature and high pressure by the compressor 22 exchanges heat with the outdoor air in the outdoor heat exchanger 23 and releases heat. At this time, the propeller fan 24 rotates to forcibly flow the outside air to the outer periphery of the outdoor heat exchanger 23 to promote heat exchange. The refrigerant that has passed through the outdoor heat exchanger 23 and released heat is depressurized in the expansion valve 25, and its temperature drops. The refrigerant with a lowered temperature flows into the first indoor heat exchanger 32a, and the refrigerant is not depressurized by the fully open dehumidification valve 36 and flows directly to the second indoor heat exchanger 32b.

[0021] The low-temperature refrigerant flowing into the indoor heat exchanger 32 exchanges heat with the indoor air in the indoor heat exchanger 32 and cools the air in the room R. The cooled air is blown into the room R by the indoor fan 31. The indoor fan 31 forcibly flows the air around the outer periphery of the indoor heat exchanger 32 to promote heat exchange with the refrigerant.

[0022] During the heating operation, the switching valve 21 switches the refrigerant flow path and circulates the refrigerant in the opposite direction to that during the cooling operation.

[0023] FIG. 2 shows a control block diagram of the air conditioner 10 (see FIG. 1). The indoor unit 30 includes an indoor control unit 40 (control unit) that controls the indoor fan 31, the left and right louvers 34, the up and down louvers 35, and the dehumidifying valve 36, a temperature sensor 41 that detects the indoor temperature, a display lamp 42 that displays the operation status by the indoor control unit 40, and a remote control transceiver 43 that exchanges predetermined information with the remote control 12.

[0024] The indoor control unit 40 includes a storage unit 44 that stores data received via the remote control transceiver 43, the detection value of the temperature sensor 41, the set temperature, reference time, and other predetermined programs described later, a plurality of timers t1 to t5 that measure the elapsed time, and a dehumidification permission determination means 46 that determines whether to perform a cleaning dehumidification operation by reheating and dehumidifying after the end of the cleaning cooling operation described later.

[0025] The outdoor unit 20 has an outdoor control unit 45 that is electrically connected to the indoor control unit 40. The indoor control unit 40 can control the switching valve 21, the compressor 22, the propeller fan 24, and the expansion valve 25 via the outdoor control unit 45.

[0026] The air conditioner 10 also has a function of performing a cleaning operation to clean the dust adhering to the surface of the indoor heat exchanger 32 (see FIG. 1). Hereinafter, the control content of the cleaning operation of the air conditioner 10 will be described.

[0027] Figures 3 and 4 show flowcharts illustrating the control of the air conditioner unit 10. When a signal to start the cleaning operation is transmitted from the remote control 12 (see Figure 2) to the indoor control unit 40, or when predetermined conditions are met after the end of cooling or heating operation (for example, a predetermined amount of time has elapsed since the end of the previous cleaning operation), the indoor control unit 40 starts the cleaning operation (start) by indicating that the indicator lamp 42 is performing the cleaning operation.

[0028] When the washing operation starts, in step St1, the first timer t1 starts from "0". The first timer t1 measures the duration of the washing operation.

[0029] In step St2, the room control unit 40 acquires the room temperature Tr detected by the temperature sensor 41.

[0030] Step St3 determines whether the room temperature Tr falls within a predetermined temperature range. Specifically, it determines whether the room temperature Tr is less than the reference room temperature value Ts1 and greater than or equal to the minimum reference value Ts2, which is set lower than the reference room temperature value Ts1 (Ts2 ≤ Tr < Ts1). The reference room temperature value Ts1 and the minimum reference value Ts2 are predetermined values.

[0031] If the room temperature Tr falls below the minimum standard value Ts2 (Tr < Ts2), the cleaning operation will terminate (end).

[0032] If the room temperature Tr is greater than or equal to the minimum reference value Ts2 and less than the reference room temperature value Ts1 (Ts2 ≤ Tr < Ts1), then in step St4, the second timer t2 starts from "0".

[0033] Subsequently, in step St5, a cleaning heating operation is performed to warm the indoor R. See also Figures 1 and 2. The purpose of the cleaning heating operation is to create an environment suitable for condensation on the surface of the indoor heat exchanger 32. The cleaning heating operation is performed in the same way as normal heating operation, by the outdoor control unit 45, which receives instructions from the indoor control unit 40, controlling the compressor 22, the expansion valve 25 and the switching valve 21.

[0034] The cleaning heating operation is performed based on pre-set conditions. For example, in the cleaning heating operation, the set temperature Ts3 is set to a temperature at least higher than the standard room temperature value Ts1, and the airflow from the indoor fan 31 is set to maximum. The vertical louvers 35 and the horizontal louvers 34 are fixed in the position at which the airflow is at maximum.

[0035] In Step St6, the room control unit 40 acquires the room temperature Tr detected by the temperature sensor 41.

[0036] In step St7, it is determined whether the room temperature Tr has reached a predetermined set temperature Ts3 due to the cleaning heating operation (Tr ≥ Ts3).

[0037] When the room temperature Tr reaches the set temperature Ts3 (Tr ≥ Ts3), in step St8, the third timer t3 is started from "0".

[0038] Subsequently, in step St9, a cleaning cooling operation is performed to generate condensation water on the surface of the indoor heat exchanger 32. The condensation water generated washes away dust and debris adhering to the surface of the indoor heat exchanger 32. The cleaning cooling operation is performed in the same way as normal cooling operation, by the outdoor control unit 45, which receives a command from the indoor control unit 40, controlling the compressor 22, the expansion valve 25, and the switching valve 21.

[0039] The cleaning cooling operation is performed based on preset conditions. For example, the set temperature Ts4 for the cleaning cooling operation is set to a predetermined temperature (e.g., the minimum reference value Ts2), and the left and right louvers 34 and the up and down louvers 35 are fixed in the position at maximum airflow. The airflow is appropriately changed according to the room temperature Tr. The set temperature Ts4 is the operation switching temperature for switching from cleaning cooling operation to cleaning drying operation.

[0040] Furthermore, the cleaning cooling operation is controlled by the indoor control unit 40 to stop the compressor 22 after a preset first predetermined time has elapsed and to perform a fan operation, driving only the indoor fan 31, for a preset second predetermined time. The first predetermined time is set to be longer than the second predetermined time. The indoor control unit 40 controls the system to repeatedly perform the cooling operation and the fan operation until the termination conditions for the cleaning cooling operation are met. By performing the fan operation, the moisture accumulated in the indoor unit 30 is returned to the room R, increasing the humidity in the room and increasing the amount of condensation water generated by the cleaning cooling operation, thereby improving the cleaning efficiency of the indoor heat exchanger 32. Detailed control contents during the cleaning cooling operation will be described later.

[0041] Furthermore, in step St7, if the room temperature Tr has not reached the set temperature Ts3 (Tr < Ts3), in step St10, it is determined whether the time measured by the second timer t2 (duration of the cleaning heating operation) has elapsed to a predetermined reference time m1 (first reference time) (t2 > m1).

[0042] If the time measured by the second timer t2 has elapsed beyond the reference time m1 (t2 > m1), the third timer t3 is started from "0" (step St8), and then the cooling operation for cleaning is performed (step St9).

[0043] If the time measured by the second timer t2 has not elapsed beyond the reference time m1 (t2 < m1), the heating operation for cleaning will continue.

[0044] Furthermore, in step St3, if the room temperature Tr exceeds the reference room temperature value Ts1 (Tr > Ts1), the indoor control unit 40 determines that the indoor R is already a suitable environment for condensation on the surface of the indoor heat exchanger 32. Therefore, the indoor control unit 40 does not perform the cleaning heating operation (step St5), but instead starts the third timer (step St8) and performs the cleaning cooling operation (step St9).

[0045] After the start of the cooling operation for cleaning in step St9, in step St11, the indoor control unit 40 acquires the room temperature Tr detected by the temperature sensor 41.

[0046] Subsequently, in step St12, it is determined whether the room temperature Tr has fallen below the set temperature Ts4, which is the operating switch temperature for the cleaning cooling operation (Tr ≤ Ts4).

[0047] If the room temperature Tr falls below the set temperature Ts4 (Tr ≤ Ts4), step St13 determines whether the time measured by the first timer t1 (duration of the washing operation) has elapsed to a preset reference time m2 (second reference time) (t1 > m2).

[0048] If the time measured by the first timer t1 has not elapsed beyond the reference time m2 (t1 ≤ m2), the cleaning cooling operation is stopped, the second timer t2 is reset and restarted (step St4), and the cleaning heating operation is performed again (step St5). If the cleaning cooling operation is continued, the temperature of the refrigerant flowing through the indoor heat exchanger 32 will continue to decrease, and the condensation water adhering to the surface of the indoor heat exchanger 32 may freeze. If the condensation water freezes, the dust adhering to the surface of the indoor heat exchanger 32 cannot be washed away by the condensation water, and the cleaning efficiency in the cleaning operation decreases. During the cleaning cooling operation, if the room temperature Tr detected by the temperature sensor 41 falls below the set temperature Ts4 and the reference time m2 has not elapsed, the cleaning heating operation is restarted to raise the room temperature. This raises the surface temperature of the indoor heat exchanger 32 to prevent the condensation water from freezing and prevents a decrease in cleaning efficiency in the cleaning operation.

[0049] In step St13, if the time measured by the first timer t1 (duration of cleaning operation) has exceeded the reference time m2 (t1 > m2), or if the room temperature Tr has reached or exceeded the set temperature Ts4 in step St12 (Tr ≥ Ts4), in step St14, it is determined whether the time measured by the third timer t3 (duration of cleaning cooling operation) has exceeded the preset reference time m3 (t3 > m3).

[0050] In step St14, if the time measured by the third timer has exceeded the reference time (t3 > m3), the dehumidification feasibility determination means 46 determines whether or not to perform a dehumidification operation for cleaning by reheat dehumidification (step St15).

[0051] If the conditions for dehumidification feasibility described later are met in step St15, and the dehumidification feasibility determination means 46 determines that a dehumidification operation for cleaning by reheat dehumidification is necessary, then in step St16, the fourth timer t4 is started from "0".

[0052] Subsequently, in step St17, a dehumidifying operation for cleaning is started to dry one of the indoor heat exchangers 32. The dehumidifying operation for cleaning is performed by circulating the refrigerant in the cooling cycle, using the first indoor heat exchanger 32a as a condenser, causing condensation on the first indoor heat exchanger 32a side, and then throttling the dehumidifying valve 36 to use the second indoor heat exchanger 32b as an evaporator.

[0053] Furthermore, if the time measured by the third timer t3 (duration of the cleaning cooling operation) in step St14 has not elapsed to the reference time m3 (t3 ≤ m3), then in step St18, it is determined whether the time measured by the first timer t1 (duration of the cleaning operation) has elapsed to the preset reference time m4 (t1 > m4).

[0054] If the time measured by the first timer t1 (duration of the cleaning operation) has not elapsed beyond the reference time m4 (t1 ≤ m4), the cleaning cooling operation (step St9) is continued.

[0055] If the time measured by the first timer t1 (duration of the cleaning operation) has elapsed beyond the reference time m4 (t1 > m4), the cleaning cooling operation is terminated.

[0056] When the cleaning cooling operation is completed, the dehumidification feasibility determination means 46 determines whether or not to perform a cleaning dehumidification operation using reheat dehumidification (step St15).

[0057] Then, if the conditions for dehumidification feasibility described later in step St15 are met and the dehumidification feasibility determination means 46 determines that a dehumidification operation for cleaning by reheat dehumidification is necessary, the indoor control unit 40 starts the fourth timer t4 from "0" (step St16), throttles the dehumidification valve 36, and starts the dehumidification operation for cleaning by using the first indoor heat exchanger 32a as a condenser and the second indoor heat exchanger 32b as an evaporator (step St17).

[0058] After the start of the dehumidifying operation for cleaning in step St17, in step St19, it is determined whether the time measured by the fourth timer t4 (duration of the drying operation for cleaning) has elapsed to a preset reference time m5 (t4 > m5).

[0059] If the time measured by the fourth timer t4 (duration of the cleaning dehumidification operation) has not elapsed beyond the preset reference time m5 (t4 ≤ m5), the cleaning dehumidification operation will continue.

[0060] When the time measured by the fourth timer t4 has elapsed to a preset reference time m5 (t4 > m5), the indoor control unit 40 terminates the dehumidifying operation for cleaning, starts the fifth timer t5 from "0" (step St20), and then starts the drying operation for cleaning (step St21).

[0061] In step St21, a cleaning and drying operation is started to dry the indoor heat exchanger 32. The cleaning and drying operation is performed by the outdoor control unit 45, which receives a command from the indoor control unit 40, controlling the compressor 22, the expansion valve 25, and the switching valve 21, just like in normal heating operation.

[0062] The cleaning and drying operation is performed based on pre-set conditions. For example, the set temperature Ts6 (not shown) for the cleaning and drying operation is set to a predetermined temperature. The hot start function, which prevents the blowing of cold air when heating operation starts, and the defrosting operation function, which warms the outdoor heat exchanger 23 to melt frost, are disabled. The upper and lower louvers 35 and the left and right louvers 34 are fixed in the position at maximum airflow. The airflow is changed as appropriate according to the room temperature Tr.

[0063] After the start of the cleaning and drying operation in step St21, in step St22, it is determined whether the time measured by the fifth timer t5 (duration of the cleaning and drying operation) has elapsed to a preset reference time m6 (t5 > m6).

[0064] If the time measured by the fifth timer t5 (duration of the washing and drying operation) has not elapsed beyond the preset reference time m6 (t5 ≤ m6), the washing and drying operation will continue.

[0065] When the time measured by the fifth timer t5 has elapsed to a preset reference time m6 (t5 > m6), the indoor control unit 40 terminates the cleaning operation (end). At the end of the cleaning operation, the indoor control unit 40 turns off the indicator lamp 42 provided on the indoor unit 30 and performs the operation stop processing for the upper and lower louvers 35 and the left and right louvers 34.

[0066] In this way, during the cleaning operation in which condensation forms on the first indoor heat exchanger 32a and the second indoor heat exchanger 32b by the cleaning cooling operation, and dust adhering to the surface of the indoor heat exchanger 32 is washed away with the condensed water, the condensed water adhering to one of the first indoor heat exchanger 32a and the second indoor heat exchanger 32b is dried with the cleaning dehumidification operation, and once the drying of one is complete, the other indoor heat exchanger 32 is dried with the cleaning drying operation. This reduces the return of moisture to the room compared to when both indoor heat exchangers 32 are dried simultaneously, and prevents the humidity in the room from rising, which would cause discomfort to people inside the room.

[0067] Furthermore, since one of the indoor heat exchangers 32 is dried by a cleaning dehumidification operation (reheat dehumidification), the cleaning drying operation only needs to evaporate the other indoor heat exchanger 32, thus shortening the drying operation time.

[0068] Next, the conditions for determining whether or not dehumidification is possible for the dehumidification feasibility determination means 46, which determines whether or not it is necessary to perform the dehumidification operation for cleaning in this embodiment, will be described in detail.

[0069] Reference numeral 37 denotes a humidity sensor installed in the indoor unit 30 for detecting the humidity of the room R. The dehumidification feasibility determination means 46 determines that if the humidity detected by the humidity sensor 37 is less than a predetermined humidity (in this case, 50%), it is not necessary to perform a dehumidification operation for cleaning, and determines that if the humidity detected by the humidity sensor 37 is equal to or greater than the predetermined humidity (in this case, 50% or more), it is necessary to perform a dehumidification operation for cleaning.

[0070] Furthermore, the conditions for whether or not dehumidification is possible based on humidity may be such that the predetermined humidity changes depending on the temperature of the room R, and the predetermined humidity may be increased so that the higher the detected value of the temperature sensor 41 and the higher the room temperature, the easier it is to perform the dehumidification operation for cleaning (reheat dehumidification).

[0071] Next, another embodiment will be described regarding a means for determining whether dehumidification is possible without using the humidity sensor 37. 38 is an indoor heat exchange sensor installed in the indoor heat exchanger 32 that detects the heat exchange temperature. The indoor control unit 40 applies the heat exchange temperature detected by the indoor heat exchange sensor 38 and the indoor temperature detected by the temperature sensor 41 to the calculation table in Figure 5 that is stored in advance. If it estimates that the current humidity is within the range of a predetermined humidity in the figure, it determines that there is no need to perform a dehumidification operation for cleaning. If it estimates that the current humidity is outside the range of a predetermined humidity in the figure, it determines that there is a need to perform a dehumidification operation for cleaning.

[0072] Next, we will describe another embodiment of a method for determining whether dehumidification is possible without using humidity as a condition for dehumidification. 39 is a motion sensor installed in the indoor unit 30 that detects whether or not there is a person in the room R. The indoor control unit 40 determines whether or not there is a person in the room R based on the value detected by the motion sensor 39.

[0073] The dehumidification feasibility determination means 46 determines, based on the detection value of the human presence sensor 39, that there is a person in room R. If the first indoor heat exchanger 32a and the second indoor heat exchanger 32b, which have condensed, are dried simultaneously in a cleaning drying operation, a large amount of moisture will be returned to room R, causing discomfort to the person in room R. Therefore, a cleaning dehumidification operation (reheat dehumidification) is performed.

[0074] Furthermore, if the dehumidification feasibility determination means 46 determines, based on the detection value of the human presence sensor 39, that there are no people in the room R, it simultaneously dries the first indoor heat exchanger 32a and the second indoor heat exchanger 32b, which have condensed, using a cleaning drying operation. In this case, a large amount of moisture returns, but the drying operation can be completed before there are any people in the room R.

[0075] In this way, by using the dehumidification feasibility determination means 46 to determine whether or not to perform a dehumidification operation for cleaning, and by not performing the dehumidification operation for cleaning if the effect of moisture return is small, the time from the start to the completion of the cleaning operation can be shortened, and electricity costs can be reduced.

[0076] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. For example, in the embodiment, when the presence sensor 39 detects that there is a person in the room, a dehumidifying operation for cleaning is performed to reduce discomfort due to moisture return. However, when the presence sensor 39 detects that there is a person in the room, the dehumidifying operation for cleaning may be omitted to prevent the person in room R from feeling cold.

[0077] Furthermore, although the cycle for cleaning and dehumidifying was explained in the context of the cooling cycle, the first indoor heat exchanger 32a may be dried first by circulating the refrigerant in the heating cycle, and the cycle flow is not limited to this method. [Explanation of symbols]

[0078] 10. Air conditioning unit (air conditioner) 11 Refrigerant Circuit 21 Switching valve 22 Compressor 23 Outdoor heat exchanger 25 Expansion valve 32a First indoor heat exchanger 32b Second indoor heat exchanger 37 Humidity Sensor 38 Indoor heat exchanger sensor 39 motion sensors 40 Indoor Control Unit (Control Unit) 41 Temperature sensor 46 Means for determining whether dehumidification is possible

Claims

1. A refrigerant circuit through which the refrigerant circulates, A compressor with a variable rotational speed is provided in the refrigerant circuit, An outdoor heat exchanger is provided in the refrigerant circuit and exchanges heat with the outdoor air, An expansion valve provided in the refrigerant circuit to reduce the pressure of the refrigerant, A first indoor heat exchanger is provided in the refrigerant circuit and exchanges heat with indoor air, A second indoor heat exchanger is provided in the refrigerant circuit and exchanges heat with indoor air, A dehumidifying valve is provided between the first indoor heat exchanger and the second indoor heat exchanger, and is capable of reducing the pressure of the refrigerant by throttling the valve, A switching valve provided in the refrigerant circuit to change the direction of flow of the refrigerant, A temperature sensor that detects room temperature, The system includes a control unit that controls a cleaning cooling operation for cleaning the first indoor heat exchanger and the second indoor heat exchanger by condensing them, and a cleaning drying operation for cleaning which involves switching the switching valve so that the refrigerant flows through the refrigerant circuit in the opposite direction to the cleaning cooling operation, thereby raising the temperature of the first indoor heat exchanger and the second indoor heat exchanger and increasing the room temperature. In an air conditioner that performs a cleaning operation, in which the control unit determines that the room temperature detected by the temperature sensor has fallen below a predetermined operating switching temperature when performing the cleaning cooling operation, the control unit switches to the cleaning drying operation, The control unit can control a cleaning dehumidification operation by throttling the dehumidification valve, thereby using one of the heat exchangers, the first indoor heat exchanger or the second indoor heat exchanger, as a condenser and the other as an evaporator. The control unit is characterized in that, after the completion of the cleaning cooling operation, it performs the cleaning dehumidification operation with one heat exchanger as a condenser and the other as an evaporator, and after the cleaning dehumidification operation of one heat exchanger is completed, it performs the cleaning drying operation.

2. A dehumidification feasibility determination means is provided to determine whether or not to perform the aforementioned dehumidification operation for cleaning. The air conditioner according to claim 1, characterized in that, if the control unit determines, using the dehumidification feasibility determination means, that it is not necessary to perform the cleaning dehumidification operation, it will perform the cleaning drying operation after the cleaning cooling operation has finished without performing the cleaning dehumidification operation.

3. A humidity sensor is installed to detect the humidity inside the room. The dehumidification feasibility determination means determines that if the humidity detected by the humidity sensor at the end of the cleaning cooling operation is below a predetermined humidity, it is not necessary to perform the cleaning dehumidification operation, as described in claim 2.

4. The indoor heat exchanger is equipped with a heat exchanger temperature sensor. The dehumidification feasibility determination means determines that, at the end of the cleaning cooling operation, if the humidity estimated from the indoor temperature detected by the temperature sensor and the heat exchange temperature detected by the heat exchange temperature sensor is within a range of a predetermined humidity or less, it is not necessary to perform the cleaning dehumidification operation, as described in claim 2.

5. An indoor unit having the first indoor heat exchanger and the second indoor heat exchanger inside, and the indoor unit is equipped with a motion sensor that detects whether or not there is a person in the room. The air conditioner according to claim 2, characterized in that the dehumidification feasibility determination means determines that it is not necessary to perform the dehumidification operation for cleaning if the human presence sensor detects that there are no people in the room when the cleaning cooling operation is completed.

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