JP2019128076A - Air-conditioning system - Google Patents

Abstract

To provide an air-conditioning system for performing dehumidifying operation while reducing the possibility that insufficient indoor dehumidification makes a person in room feel uncomfortable.SOLUTION: When an indoor temperature satisfies thermo-off temperature conditions, a control part (6) of an air-conditioning system (1) controls the capacity of a compressor (21) and the airflow of an indoor fan (32) during dehumidifying operation so that the evaporation temperature of refrigerant in an indoor heat exchanger (31) falls below the dew-point temperature of indoor air without performing thermo-off to stop the compressor (21).SELECTED DRAWING: Figure 7

Description

  Air conditioner for dehumidifying operation

  BACKGROUND Conventionally, there is an air conditioner having a refrigerant circuit configured by connecting a compressor, an outdoor heat exchanger, an expansion mechanism, and an indoor heat exchanger. Then, in this air conditioning apparatus, a dehumidifying operation may be performed in which the refrigerant sealed in the refrigerant circuit is circulated in the order of the compressor, the outdoor heat exchanger, the expansion mechanism, and the indoor heat exchanger. During the dehumidifying operation, as shown in Patent Document 1 (Japanese Patent Laid-Open No. 2004-76973), when the room temperature reaches the target room temperature, the thermo-off is performed to stop the compressor.

  In the air conditioner of Patent Document 1, as described above, when the room temperature reaches the target room temperature during the dehumidifying operation, it is determined that the thermo-off condition is satisfied, and the thermo-off is performed.

  However, in such a dehumidifying operation, the room temperature may reach the target room temperature without being sufficiently dehumidified in the room, and the thermo-off may be performed. There is a risk of

  An air conditioner according to a first aspect includes a refrigerant circuit, an indoor fan, and a control unit. The refrigerant circuit is configured by connecting a compressor, an outdoor heat exchanger, an expansion mechanism, and an indoor heat exchanger. The indoor fan sends indoor air to the indoor heat exchanger. The control unit performs the dehumidifying operation in which the refrigerant sealed in the refrigerant circuit is circulated in the order of the compressor, the outdoor heat exchanger, the expansion mechanism, and the indoor heat exchanger. The control unit is configured such that the evaporation temperature of the refrigerant in the indoor heat exchanger falls below the dew point temperature of the indoor air without performing the thermo-off for stopping the compressor when the room temperature satisfies the thermo-off temperature condition during the dehumidifying operation. , Control the capacity of the compressor and the air volume of the indoor fan.

  Here, even if the thermo-off temperature condition is satisfied, thermo-off is not performed, and the room dehumidification is continued in a state where condensation of the room air reliably occurs in the indoor heat exchanger. For this reason, when the thermo-off temperature condition is satisfied, the amount of dehumidification can be increased as compared to the case where the thermo-off is performed, and the possibility that the person in the room feels uncomfortable due to the lack of dehumidification in the room can be reduced.

  In the air conditioner according to the second aspect, in the air conditioner according to the first aspect, the control unit controls the air volume of the indoor fan to the minimum air volume, and the evaporation temperature of the compressor falls below the dew point temperature Control to make it smaller in the range.

  Here, the flow rate of the refrigerant that performs heat exchange in the indoor heat exchanger and the air volume of the indoor air can be reduced, so that the heat exchange between the refrigerant and the indoor air can be suppressed. It is possible to reduce the possibility that the room temperature may be too low and the occupant may feel uncomfortable.

  The air conditioning apparatus according to the third aspect is the air conditioning apparatus according to the second aspect, wherein the control unit performs control to reduce the capacity of the compressor until the indoor temperature rises.

  Here, by reducing the flow rate of the refrigerant that performs heat exchange in the indoor heat exchanger to a flow rate at which dehumidification is performed without lowering the indoor temperature, it is possible to further reduce the possibility that the occupants feel uncomfortable. .

  The air conditioning apparatus according to a fourth aspect is the air conditioning apparatus according to the second or third aspect, wherein the control unit performs control to reduce the capacity of the compressor within the range of the lower limit value of the evaporation temperature.

  Here, by excessively cooling the indoor air in the indoor heat exchanger, it is possible to reduce the possibility of the occurrence of condensation in the vicinity of the outlet of the indoor unit that accommodates the indoor heat exchanger.

  The air conditioning apparatus according to a fifth aspect is the air conditioning apparatus according to the fourth aspect, wherein the control unit lowers the lower limit value of the evaporation temperature during the dehumidifying operation.

  Here, the range in which the evaporation temperature is lowered can be expanded, and the evaporation temperature can be made to surely fall below the dew point temperature.

  The air conditioning apparatus according to a sixth aspect is the air conditioning apparatus according to the fifth aspect, wherein the control unit determines the lower limit value of the evaporation temperature from the room temperature and the room humidity.

  Here, since the range in which the evaporation temperature is lowered can be expanded in consideration of the room temperature and the room humidity, the occurrence of condensation can be suppressed as much as possible.

  An air conditioning apparatus according to a seventh aspect is the air conditioning apparatus according to any of the first to sixth aspects, wherein the control unit is configured to be able to select a plurality of dehumidifying operation modes having different dehumidifying levels as the dehumidifying operation. Has been.

  Here, the dehumidifying operation suitable for the dehumidifying level needs of the occupant can be performed.

  The air conditioning apparatus according to an eighth aspect is the air conditioning apparatus according to the seventh aspect, wherein the control unit changes the thermo-off temperature condition to a lower temperature side as the dehumidifying level in the selected dehumidifying operation mode is higher.

  Here, the higher the dehumidification level is, the harder it is to satisfy the first thermo-off temperature condition, so the dehumidification amount can be increased until the first thermo-off temperature condition is satisfied.

It is a schematic block diagram of the air conditioning apparatus concerning one embodiment of this indication. It is an external appearance perspective view of the indoor unit which comprises an air conditioning apparatus. It is a schematic side surface sectional view of an indoor unit, and is an IO I sectional view of FIG. It is a control block diagram of an air conditioning apparatus. It is a control flowchart at the time of air conditioning operation. It is a control flowchart (mode selection) at the time of dehumidification operation. It is a control flowchart (dehumidification operation mode L, M, H) at the time of dehumidification operation. It is a flow chart which shows dehumidification continuation control in modification A. It is a flowchart which shows the dehumidification continuation control in the modification B. FIG.

  Hereinafter, embodiments of the air conditioner will be described based on the drawings.

(1) Device Configuration FIG. 1 is a schematic configuration diagram of an air conditioner 1 according to an embodiment of the present disclosure.

<Overall>
The air conditioning apparatus 1 is an apparatus that performs air conditioning in a room such as a building by a vapor compression refrigeration cycle. The air conditioner 1 mainly includes an outdoor unit 2, an indoor unit 3, and a liquid refrigerant communication pipe 4 and a gas refrigerant communication pipe 5 that connect the outdoor unit 2 and the indoor unit 3. The vapor compression type refrigerant circuit 10 of the air conditioner 1 is configured by connecting the outdoor unit 2 and the indoor unit 3 via the liquid refrigerant communication pipe 4 and the gas refrigerant communication pipe 5.

<Outdoor unit>
The outdoor unit 2 is installed outdoors (in the vicinity of the roof of a building, the outer wall of a building, etc.). The outdoor unit 2 is connected to the indoor unit 3 via the liquid refrigerant communication pipe 4 and the gas refrigerant communication pipe 5 as described above, and constitutes a part of the refrigerant circuit 10. The outdoor unit 2 mainly includes a compressor 21, a four-way switching valve 23, an outdoor heat exchanger 24, and an expansion valve 25.

  The compressor 21 is a mechanism that compresses low-pressure refrigerant in the refrigeration cycle to high pressure. Here, as the compressor 21, a compressor of a closed type in which a rotary or scroll type positive displacement type compression element (not shown) is rotationally driven by the compressor motor 22 is used. Further, in this case, the compressor motor 22 can be controlled in rotation speed (frequency) by an inverter or the like, whereby the capacity of the compressor 21 can be controlled.

  The four-way switching valve 23 is a valve for switching the flow direction of the refrigerant when switching between the cooling operation or the dehumidifying operation and the heating operation. The four-way switching valve 23 connects the discharge side of the compressor 21 and the gas side of the outdoor heat exchanger 24 during the cooling operation or the dehumidifying operation, and also connects the indoor heat exchanger 31 (described later) via the gas refrigerant communication pipe 5. Can be connected to the suction side of the compressor 21 (see the solid line of the four-way switching valve 23 in FIG. 1). Further, the four-way switching valve 23 connects the discharge side of the compressor 21 and the gas side of the indoor heat exchanger 31 via the gas refrigerant communication pipe 5 during the heating operation, and the gas side of the outdoor heat exchanger 24 And the suction side of the compressor 21 (see the broken line of the four-way switching valve 23 in FIG. 1).

  The outdoor heat exchanger 24 is a heat exchanger that functions as a radiator of the refrigerant during the cooling operation or the dehumidifying operation, and functions as an evaporator of the refrigerant during the heating operation. The liquid side of the outdoor heat exchanger 24 is connected to the expansion valve 25, and the gas side is connected to the four-way switching valve 23.

  The expansion valve 25 reduces the pressure of the high pressure liquid refrigerant released in the outdoor heat exchanger 24 during the cooling operation or the dehumidifying operation before sending it to the indoor heat exchanger 31, and the high pressure liquid released in the indoor heat exchanger 31 during the heating operation. This is an expansion mechanism capable of reducing the pressure before sending the refrigerant to the outdoor heat exchanger 24. Here, an electric expansion valve capable of controlling the degree of opening is used as the expansion valve 25.

  In addition, the outdoor unit 2 is provided with an outdoor fan 26 for drawing outdoor air into the unit and supplying the outdoor air to the outdoor heat exchanger 24 and discharging the outdoor air to the outside of the unit. That is, the outdoor heat exchanger 24 is a heat exchanger that radiates or evaporates the refrigerant using the outdoor air as a cooling source or a heating source. The outdoor fan 26 is rotationally driven by the outdoor fan motor 27.

  In addition, the outdoor unit 2 is provided with various sensors. Specifically, the outdoor unit 2 is provided with a suction pressure sensor 28 that detects the suction pressure Ps of the compressor 21.

<Refrigerant communication tube>
The refrigerant communication pipes 4 and 5 are refrigerant pipes that are constructed on site when the air conditioning apparatus 1 is installed at an installation place such as a building. One end of the liquid refrigerant communication pipe 4 is connected to the expansion valve 25 side of the indoor unit 2, and the other end of the liquid refrigerant communication pipe 4 is connected to the liquid side of the indoor heat exchanger 31 of the indoor unit 3. One end of the gas refrigerant communication pipe 5 is connected to the four-way switching valve 23 side of the indoor unit 2, and the other end of the gas refrigerant communication pipe 5 is connected to the gas side of the indoor heat exchanger 31 of the indoor unit 3. .

<Indoor unit>
The indoor unit 3 is installed indoors (within a building). As described above, the indoor unit 3 is connected to the outdoor unit 2 via the liquid refrigerant communication pipe 4 and the gas refrigerant communication pipe 5, and constitutes a part of the refrigerant circuit 10. The indoor unit 3 mainly includes an indoor heat exchanger 31 and an indoor fan 32.

  Here, as the indoor unit 3, an indoor unit of a type called a ceiling-embedded type is adopted. As shown in FIGS. 2 and 3, the indoor unit 3 has a casing 41 for housing the components therein. The casing 41 is composed of a casing body 41 a and a decorative panel 42 disposed below the casing body 41 a. The casing main body 41a is inserted into an opening formed in the ceiling U and disposed as shown in FIG. And, the decorative panel 42 is arranged to be fitted into the opening of the ceiling U. Here, FIG. 2 is an external perspective view of the indoor unit 3. FIG. 3 is a schematic side cross-sectional view of the indoor unit 3 and is an IO-I cross-sectional view of FIG. 2.

  The casing main body 41a is a substantially octagonal box-like body in which long sides and short sides are alternately formed in a plan view, and the lower surface is open. The casing main body 41 a has a substantially octagonal top plate 43 in which long sides and short sides are alternately and continuously formed, and a side plate 44 extending downward from the peripheral portion of the top plate 43.

  The decorative panel 42 is a plate-like body having a substantially polygonal shape (here, substantially rectangular shape) in plan view constituting the lower surface of the casing 41, and is mainly a panel body fixed to the lower end of the casing body 41a. 42a. The panel main body 42a has a suction port 45 for sucking air in the room and a blowoff port 46 for blowing air into the room formed so as to surround the circumference of the suction port 45 in plan view. The suction port 45 is a substantially rectangular opening. The suction port 45 is provided with a suction grill 47 and a suction filter 48 for removing dust in the air sucked from the suction port 45. The outlets 46 are a plurality of (here, four) side outlets 46a formed along each side of the square of the panel body 42a, and a plurality (here, formed at corners of the panel body 42a). In the above, four (4) corner air outlets 46b are provided. And in each side part outlet 46a, there are a plurality of (here, four) wind direction changing blades 49 capable of changing the wind direction angle of the air blown out into the room from each side part outlet. It is provided. The wind direction changing blade 49 is a plate-like member elongated in the longitudinal direction of the side air outlet 46a. The wind direction changing blade 49 can be turned around the longitudinal axis to change the wind direction angle in the vertical direction.

  The indoor heat exchanger 31 and the indoor fan 32 are mainly disposed inside the casing main body 41a.

  The indoor heat exchanger 31 is a heat exchanger that functions as an evaporator of the refrigerant during the cooling operation or the dehumidifying operation, and functions as a radiator of the refrigerant during the heating operation. The liquid side of the outdoor heat exchanger 31 is connected to the liquid refrigerant communication pipe 4, and the gas side is connected to the gas refrigerant communication pipe 5. The indoor heat exchanger 31 is a heat exchanger that is bent and disposed so as to surround the indoor fan 32 in plan view. The indoor heat exchanger 31 exchanges heat between the indoor air and the refrigerant drawn into the casing main body 41 a by the indoor fan 32. Further, below the indoor heat exchanger 31, a drain pan 31a for receiving drain water generated by condensing moisture in indoor air by the indoor heat exchanger 31 is disposed. The drain pan 31a is attached to the lower part of the casing main body 41a.

  The indoor fan 32 is a fan that sucks room air into the casing main body 41 a through the suction port 45 of the decorative panel 42 and blows it out of the casing main body 41 a into the room through the outlet 46 of the decorative panel 42. That is, the indoor heat exchanger 31 is a heat exchanger that radiates or evaporates the refrigerant by using indoor air as a cooling source or a heating source. Here, as the indoor fan 32, a centrifugal fan is used which sucks indoor air from below and blows it toward the outer peripheral side in a plan view. The indoor fan 32 is rotationally driven by an indoor fan motor 33 provided at the center of the top plate 43 of the casing main body 41a. Further, here, the indoor fan motor 33 can be controlled in rotational speed (frequency) by an inverter or the like, whereby the air volume of the indoor fan 32 can be controlled. Specifically, as the air volume of the indoor fan 32, the air volume H of the maximum air volume, the medium air volume M of the medium air volume smaller than the air volume H, the air volume L of the small air volume smaller than the air volume M, and the minimum of the air volume L Four of the air volume LL, of the air volume are prepared. Here, the air volume LL is an air volume that can not be set by the occupant by the remote control 60 (described later).

  The indoor unit 3 is provided with various sensors. Specifically, the indoor unit 3 is provided with an indoor temperature sensor 34 and an indoor humidity sensor 35 for detecting the temperature (indoor temperature Tr) and the humidity (indoor humidity Hr) of the indoor air sucked into the indoor unit 3. ing.

(2) Control Configuration FIG. 4 is a control block diagram of the air conditioner 1.

<Overall>
The air conditioner 1 as the refrigeration system has a control unit 6 in which the outdoor control unit 20, the indoor control unit 30, and the remote control 60 are connected via a transmission line or a communication line in order to perform operation control of the component devices. have. The outdoor control unit 20 is provided in the indoor unit 2. The indoor control unit 30 is provided in the indoor unit 3. The remote control 60 is provided indoors. Here, although the control units 20 and 30 and the remote control 60 are connected by wire via a transmission line or a communication line, they may be connected wirelessly.

<Outdoor control unit>
As described above, the outdoor control unit 20 is provided in the outdoor unit 2 and mainly includes the outdoor CPU 20a, the outdoor transmission unit 20b, and the outdoor storage unit 20c. The indoor control unit 20 can receive a detection signal of the suction pressure sensor 28.

  The outdoor CPU 20a is connected to the outdoor transmission unit 20b and the outdoor storage unit 20c. The heat source side transmission unit 20b transmits control data and the like with the indoor control unit 30a. The outdoor storage unit 20c stores control data and the like. Then, the outdoor CPU 20a transmits and reads control data and the like via the outdoor transmission unit 20b and the outdoor storage unit 20c, and the component devices 21, 23, 25, 26 and the like provided in the outdoor unit 2 Control the operation of

<Indoor controller>
As described above, the indoor control unit 30 is provided in the indoor unit 3 and mainly includes the indoor CPU 30a, the indoor transmission unit 30b, the indoor storage unit 30c, and the indoor communication unit 30d. Have. The indoor control unit 30 can receive detection signals from the indoor temperature sensor 34 and the indoor humidity sensor 35.

  The indoor CPU 30a is connected to the indoor transmission unit 30b, the indoor storage unit 30c, and the indoor storage unit 30d. The indoor transmission unit 30 b transmits control data and the like to and from the outdoor control unit 20. The indoor storage unit 30 b stores control data and the like. The indoor communication unit 30 c transmits and receives control data and the like to and from the remote control 60. The indoor CPU 30a transmits and reads and writes control data, etc. via the indoor transmission unit 30b, the indoor storage unit 30c, and the indoor communication unit 30d, and the component devices provided in the indoor unit 3 Perform operation control such as 32, 49.

<Remote control>
As described above, the remote control 60 is provided indoors and mainly includes the remote control CPU 61, the remote control storage unit 62, the remote control communication unit 63, the remote control operation unit 64, and the remote control display unit 65. There is.

  The remote control CPU 61 is connected to the remote control communication unit 62, the remote control storage unit 63, the remote control operation unit 64, and the remote control display unit 65. The remote control communication unit 62 transmits and receives control data and the like to and from the indoor communication unit 30c. The remote control storage unit 63 stores control data and the like. The remote control operation unit 64 receives an input such as a control command from the user. The remote control display unit 65 performs operation display and the like. Then, the remote control CPU 61 receives inputs of operation commands and control commands via the remote control operation unit 64, reads and writes control data and the like from the remote control storage unit 63, and displays the operation status and control status on the remote control display unit 65. The control command and the like are issued to the indoor control unit 30 via the remote control communication unit 62 while performing the and the like.

  As described above, the air conditioner 1 as the refrigeration system includes the control unit 6 that performs operation control of the component devices. Then, the control unit 6 controls the component devices 21, 23, 25, 26, 32, 49, etc. based on the detection signals of the suction pressure sensor 28, the indoor temperature sensor 34, the indoor humidity sensor 35, etc. It is possible to perform air conditioning operation such as dehumidifying operation and heating operation and various controls.

(3) Basic Operation Next, the basic operation (heating operation, cooling operation, and dehumidifying operation) of the air conditioner 1 will be described.

<Heating operation>
The air conditioner 1 can perform a heating operation as an air conditioning operation. In the heating operation, the control unit 6 that has received the heating operation instruction via the remote control operation unit 64 controls operation of the component devices 21, 23, 25, 26, 32, 49, etc. of the outdoor unit 2 and the outdoor unit 3. Done by

  In the heating operation, the outdoor heat exchanger 24 functions as a refrigerant evaporator and the indoor heat exchanger 31 functions as a refrigerant radiator (that is, indicated by a broken line of the four-way switching valve 23 in FIG. 1). Is switched, the four-way switching valve 23 is switched.

  In the refrigerant circuit 10 in such a state, the low-pressure refrigerant in the refrigeration cycle is drawn into the compressor 21 and compressed to a high pressure in the refrigeration cycle and then discharged. The high-pressure refrigerant discharged from the compressor 21 is sent to the indoor heat exchanger 31 through the four-way switching valve 23 and the gas refrigerant communication pipe 5. The high-pressure refrigerant sent to the indoor heat exchanger 31 exchanges heat with the indoor air supplied by the indoor fan 32 in the indoor heat exchanger 31 and radiates heat. As a result, the room air is heated and blown out into the room. The high-pressure refrigerant that has dissipated heat in the indoor heat exchanger 31 is sent to the expansion valve 25 through the liquid refrigerant communication pipe 4 and decompressed to a low pressure in the refrigeration cycle. The low-pressure refrigerant reduced in pressure by the expansion valve 25 is sent to the outdoor heat exchanger 24. The low-pressure refrigerant sent to the outdoor heat exchanger 24 exchanges heat with the outdoor air supplied by the outdoor fan 26 in the outdoor heat exchanger 24 and evaporates. The low-pressure refrigerant evaporated in the outdoor heat exchanger 24 is again sucked into the compressor 21 through the four-way switching valve 23. As described above, in the heating operation, the control unit 6 causes the refrigerant enclosed in the refrigerant circuit 10 to circulate in the order of the compressor 21, the indoor heat exchanger 31, the expansion valve 25, and the outdoor heat exchanger 24. It is supposed to be.

<Cooling operation>
The air conditioner 1 can perform the cooling operation as the air conditioning operation. In the cooling operation, the control unit 6 that has received the cooling operation command via the remote control operation unit 64 controls operation of the components 21, 23, 25, 26, 32, 49, etc. of the outdoor unit 2 and the outdoor unit 3. Done by

  In the cooling operation, the outdoor heat exchanger 24 functions as a radiator of the refrigerant, and the indoor heat exchanger 31 functions as an evaporator of the refrigerant (ie, indicated by the solid line of the four-way switching valve 23 in FIG. 1). Is switched, the four-way switching valve 23 is switched.

  In the refrigerant circuit 10 in such a state, the low-pressure refrigerant in the refrigeration cycle is drawn into the compressor 21 and compressed to a high pressure in the refrigeration cycle and then discharged. The high-pressure refrigerant discharged from the compressor 21 is sent to the outdoor heat exchanger 24 through the four-way switching valve 23. The high-pressure refrigerant sent to the outdoor heat exchanger 24 exchanges heat with the outdoor air supplied by the outdoor fan 26 in the outdoor heat exchanger 24 and radiates heat. The high-pressure refrigerant that has dissipated heat in the outdoor heat exchanger 24 is sent to the expansion valve 25 and decompressed to a low pressure in the refrigeration cycle. The low pressure refrigerant decompressed in the expansion valve 25 is sent to the indoor heat exchanger 31 through the liquid refrigerant communication pipe 4. The low-pressure refrigerant sent to the indoor heat exchanger 31 exchanges heat with the indoor air supplied by the indoor fan 32 in the indoor heat exchanger 31 to evaporate. As a result, the room air is cooled and blown out into the room. The low pressure refrigerant evaporated in the indoor heat exchanger 31 is again sucked into the compressor 21 through the gas refrigerant communication pipe 5 and the four-way switching valve 23. As described above, in the cooling operation, the control unit 6 causes the refrigerant enclosed in the refrigerant circuit 10 to circulate in the order of the compressor 21, the outdoor heat exchanger 24, the expansion valve 25, and the indoor heat exchanger 31. It is supposed to be.

<Dehumidifying operation>
The air conditioning apparatus 1 can perform the dehumidifying operation as the air conditioning operation. In the dehumidifying operation, the control unit 6 that has received the dehumidifying operation command via the remote control operation unit 64 controls the operation of the outdoor unit 2 and the components 21, 23, 26, 32, 49, etc. of the outdoor unit 3 Done by

  In the dehumidifying operation, as in the cooling operation, the outdoor heat exchanger 24 functions as a radiator of the refrigerant and the indoor heat exchanger 31 functions as an evaporator of the refrigerant (that is, the four-way switching in FIG. 1) The four-way switching valve 23 is switched so as to be in the state shown by the solid line of the valve 23).

  In the refrigerant circuit 10 in such a state, the low-pressure refrigerant in the refrigeration cycle is drawn into the compressor 21 and compressed to a high pressure in the refrigeration cycle and then discharged. The high-pressure refrigerant discharged from the compressor 21 is sent to the outdoor heat exchanger 24 through the four-way switching valve 23. The high-pressure refrigerant sent to the outdoor heat exchanger 24 exchanges heat with the outdoor air supplied by the outdoor fan 26 in the outdoor heat exchanger 24 and radiates heat. The high-pressure refrigerant that has dissipated heat in the outdoor heat exchanger 24 is sent to the expansion valve 25 and decompressed to a low pressure in the refrigeration cycle. The low pressure refrigerant decompressed in the expansion valve 25 is sent to the indoor heat exchanger 31 through the liquid refrigerant communication pipe 4. The low-pressure refrigerant sent to the indoor heat exchanger 31 exchanges heat with the indoor air supplied by the indoor fan 32 in the indoor heat exchanger 31 to evaporate. As a result, the room air is dehumidified and blown out into the room. The low pressure refrigerant evaporated in the indoor heat exchanger 31 is again sucked into the compressor 21 through the gas refrigerant communication pipe 5 and the four-way switching valve 23. As described above, in the dehumidifying operation, the control unit 6 causes the refrigerant sealed in the refrigerant circuit 10 to circulate in the order of the compressor 21, the outdoor heat exchanger 24, the expansion valve 25, and the indoor heat exchanger 31. It is supposed to be.

(4) Control in Cooling Operation In the above-described cooling operation, the following control is performed. FIG. 5 is a flowchart of the cooling operation.

<Step ST1 (Thermo-on)>
The control unit 6 performs the target evaporation temperature of the evaporation temperature Te of the refrigerant in the refrigerant circuit 10 at step ST1, that is, at the time of the cooling operation (at the time of the operation of circulating the refrigerant by operating the compressor 21). The capacity control is performed to control the capacity of the compressor 21 so as to be Tecs. In addition, the control unit 6 sets the selected air volume (here, the air volume L, the air volume selected by the room occupant by inputting the air volume of the indoor fan 32 from the remote control operation unit 64 of the remote controller 60). Control to any of M and air volume H).

  The capacity control of the compressor 21 increases the capacity of the compressor 21 by increasing the rotational speed (frequency) of the compressor 21 when the evaporation temperature Te of the refrigerant is higher than the target evaporation temperature Tecs. When the evaporation temperature Te is lower than the target evaporation temperature Tecs, the control is performed to reduce the capacity of the compressor 21 by reducing the number of revolutions (frequency) of the compressor 21.

  Here, the control unit 6 determines the target evaporation temperature Tecs based on a temperature difference ΔTr obtained by subtracting the target indoor temperature Trs from the indoor temperature Tr. Specifically, the control unit 6 determines the target evaporation temperature Tecs to be lower as the temperature difference ΔTr is larger. The target indoor temperature Trs is set by the occupant inputting from the remote control operation unit 64 of the remote control 60. Further, the evaporation temperature Te of the refrigerant can be obtained by converting the suction pressure Ps into the saturation temperature of the refrigerant. The evaporation temperature Te of the refrigerant represents the low-pressure refrigerant in the refrigeration cycle flowing from the outlet of the expansion valve 25 to the suction side of the compressor 21 via the indoor heat exchanger 31 during the cooling operation. It means the temperature obtained by converting the pressure (the evaporation pressure Pe of the refrigerant in the refrigerant circuit 10) into the saturation temperature of the refrigerant, or the saturation temperature of the refrigerant in the indoor heat exchanger 31 functioning as an evaporator of the refrigerant. Therefore, when the indoor heat exchanger 31 is provided with a temperature sensor, the temperature of the refrigerant detected by the temperature sensor may be used as the evaporation temperature Te of the refrigerant.

  In addition, although the state quantity of the control object in capacity control is made into evaporation temperature Te here, you may be evaporation pressure Pe. In this case, a target evaporation pressure Pecs corresponding to the target evaporation temperature Tecs may be used as a control target value. Using the evaporation pressure Pe and the target evaporation pressure Pecs in this volume control is also the same as using the evaporation temperature Te and the target evaporation temperature Tecs.

<Step ST2 (Determination of Whether the Thermo-off Condition is Met)>
The control unit 6 determines whether the thermo-off condition is satisfied in step ST2 during the thermo-on in step ST1.

  The control unit 6 has a thermo-off temperature condition based on the indoor temperature Tr, as a determination factor for determining whether the thermo-off condition is satisfied. Then, the control unit 6 determines that the thermo-off condition is satisfied when the thermo-off temperature condition is satisfied, and determines that the thermo-off condition is not satisfied when the thermo-off temperature condition is not satisfied. Specifically, the control unit 6 determines that the indoor temperature Tr satisfies the thermal off temperature condition when the indoor temperature Tr becomes lower than the thermal off temperature Trcf during the thermal on, and the indoor temperature Tr is the thermal off temperature If it is higher than Trcf, it is determined that the thermo-off temperature condition is not satisfied. Here, the thermo-off temperature Trcf is a value obtained by adding the thermo-off temperature difference ΔTrcf to the target indoor temperature Trs. The thermo-off temperature difference ΔTrcf is set to a value of about -1 degree to +1 degree.

  Here, whether or not the thermo-off condition is satisfied is determined by whether or not the room temperature Tr has reached the thermo-off temperature Trcf, but it is not limited to this. For example, it may be determined based on whether the temperature difference ΔTr obtained by subtracting the target indoor temperature Trs from the room temperature Tr has reached the thermo-off temperature difference ΔTrcf, and the room temperature Tr reaches the thermo-off temperature Trcf as well. It is the same as judging whether you

<Step ST3 (thermo off)>
When it is determined in step ST2 that the room temperature Tr reaches the thermo-off temperature Trcf or lower in step ST2, the controller 6 stops the compressor 21 in step ST3 to stop the circulation of the refrigerant. Stop the cooling operation (thermo-off).

<Step ST4 (Determining Whether the Thermo-On Condition is Met)>
During the thermo-off of step ST3, the control unit 6 determines whether the thermo-on condition is satisfied in step ST4.

  The control unit 6 has a thermo-on temperature condition based on the indoor temperature Tr as a determination factor for determining whether the thermo-on condition is satisfied. Then, the control unit 6 determines that the thermo-on condition is satisfied when the thermo-on temperature condition is satisfied, and determines that the thermo-on condition is not satisfied when the thermo-on temperature condition is not satisfied. Specifically, the control unit 6 determines that the indoor temperature Tr satisfies the thermal on temperature condition when the indoor temperature Tr becomes higher than the thermal on temperature Trcn during the thermal off, and the indoor temperature Tr is the thermal on temperature If the temperature is lower than Trcn, it is determined that the thermo-on temperature condition is not satisfied. Here, the thermo-on temperature Trcn is a value obtained by adding the thermo-on temperature difference ΔTrcn to the target indoor temperature Trs. The thermo-on temperature difference ΔTrcn is set to a value of about 0 degrees to +2 degrees.

  Here, whether or not the thermo-on condition is satisfied is determined based on whether or not the room temperature Tr has reached the thermo-on temperature Trcn, but it is not limited to this. For example, it may be determined based on whether the temperature difference ΔTr obtained by subtracting the target indoor temperature Trs from the indoor temperature Tr has reached the thermo-on temperature difference ΔTrcn, and the indoor temperature Tr has reached the thermo-on temperature Trcn as well. It is the same as judging whether you

  Then, if it is determined in step ST4 that the thermo-on condition is satisfied in step ST4, the control unit 6 returns to step ST1, starts the compressor 21, and performs the operation of the cooling operation (thermo-on).

(5) Control in Dehumidifying Operation In the above dehumidifying operation, the following control is performed. 6 is a flowchart (mode selection) of the dehumidifying operation, and FIG. 7 is a flowchart (dehumidifying operation mode L, M, H) of the dehumidifying operation.

<Step ST11 (mode selection)>
Here, a plurality of dehumidifying operation modes having different dehumidifying levels are prepared as the dehumidifying operation in order to meet the dehumidifying level needs of the occupants. Here, the dehumidification level means the degree of the indoor humidity Hr to be obtained by the dehumidifying operation, and the lower the room humidity Hr to be obtained by the dehumidifying operation, the higher the dehumidifying level. Specifically, as the dehumidifying operation mode, the dehumidifying operation mode L having the lowest dehumidifying level, the moderate dehumidifying level dehumidifying operation mode M having the higher dehumidifying level than the dehumidifying operating mode L, and the dehumidifying operation mode M Three of the dehumidifying operation mode H, which has a high level, are prepared in the control unit 6. Here, the selection of the dehumidifying operation mode is selected by the room occupant from the remote control operation unit 64 of the remote control 60 in step ST11.

<Step ST12 (Dehumidifying Operation Mode L)>
When the dehumidifying operation mode L is selected in step ST11, the control unit 6 controls step ST12 (that is, steps ST21 to ST27).

-Step ST21 (Thermo-on)-
The control unit 6 performs the evaporation temperature Te of the refrigerant in the refrigerant circuit 10 at the target evaporation temperature at step ST21, that is, at the time of the operation of the dehumidifying operation (at the time of the operation of circulating the refrigerant by operating the compressor 21). Capacity control is performed to control the capacity of the compressor 21 so as to be Teds. Further, the control unit 6 performs air volume control for limiting the air volume of the indoor fan 32 to the air volume L or the air volume LL, unlike the step ST1 during the cooling operation, during the thermo-on of the step ST21.

  The displacement control of the compressor 21 is the same as step ST1 in the cooling operation except that the target evaporation temperature Tecs is set to the target evaporation temperature Teds. Therefore, the description of the control of the displacement of the compressor 21 is omitted here. Here, the target evaporation temperature Teds is set to a value equal to or less than the target evaporation temperature Tecs.

-Step ST22 (Determination 1 of Thermo OFF Condition)-
The control unit 6 determines whether or not the thermo-off condition is satisfied in step ST22 during the thermo-on in step ST21.

  The control unit 6 has a first thermo-off temperature condition based on the indoor temperature Tr and a thermo-off humidity condition based on the indoor humidity Hr as determination elements for determining whether the thermo-off condition is satisfied. Then, when both the first thermo-off temperature condition and the thermo-off humidity condition are satisfied, the control unit 6 determines that the thermo-off condition is satisfied, and one or both of the first thermo-off temperature condition and the thermo-off humidity condition are satisfied. If not, it is determined that the thermo-off condition is not satisfied. That is, in the dehumidifying operation mode L, unlike step ST2 at the time of the cooling operation, it is determined whether or not the thermo-off condition is satisfied in consideration of the thermo-off temperature condition as well as the thermo-off temperature condition.

  Specifically, during the thermo-on, the control unit 6 lowers the room temperature Tr and continues the state in which the room temperature Tr has reached the first thermo-off temperature TrdfL1 or less for a predetermined time tL. Is determined to satisfy the condition, and the first thermo-off is performed when the indoor temperature Tr is higher than the first thermo-off temperature TrdfL1 or when the state where the indoor temperature Tr reaches the first thermo-off temperature TrdfL1 does not continue for a predetermined time tL. It is determined that the temperature condition is not satisfied. Here, the first thermo-off temperature TrdfL1 is a value obtained by adding the first thermo-off temperature difference ΔTrdfL1 to the target indoor temperature Trs. The first thermo-off temperature difference ΔTrdfL1 is set to a value of about -1 degree to +1 degree, and the predetermined time tL is set to a value of about several tens of seconds to several minutes. Further, the first thermo-off temperature TrdfL1 (= target indoor temperature Trs + first thermo-off temperature difference ΔTrdfL1) may have the same value as the thermo-off temperature Trcf (= target indoor temperature Trs + thermo-off temperature difference ΔTrcf) during the cooling operation, It may be a low value.

  Further, the control unit 6 determines that the thermo-off humidity condition is satisfied when the indoor humidity Hr becomes low during the thermo-ON and the indoor humidity Hr reaches the target indoor humidity HrsL, and the indoor humidity Hr is greater than the target indoor humidity HrsL. If it is too high, it is determined that the thermo-off humidity condition is not satisfied. Here, when the dehumidifying operation mode L is selected in step ST11, the target indoor humidity HrsL is set to a value at which the dehumidifying level of about 60% to 70% is low (that is, a high relative humidity value).

  Here, whether or not the thermo-off condition is satisfied is determined based on whether or not the indoor temperature Tr has reached the first thermo-off temperature TrdfL1 and whether or not the indoor humidity Hr has reached the target indoor humidity HrsL. It is not limited to this. For example, whether the temperature difference ΔTr obtained by subtracting the target indoor temperature Trs from the indoor temperature Tr has reached the first thermo-off temperature difference ΔTrdfL1 and the humidity difference ΔHr obtained by subtracting the target indoor humidity Hrs from the indoor humidity Hr is 0 (zero). It may be judged by whether it reached. The determination based on the temperature difference ΔTr and the humidity difference ΔHr is also the same as determining whether the room temperature Tr has reached the first thermo-off temperature TrdfL1 and whether the room humidity Hr has reached the target room humidity HrsL. It is.

-Step ST23 (Thermo off)-
The control unit 6 is configured to satisfy the thermo-off condition by the indoor humidity Hr reaching the target indoor humidity HrsL when the indoor temperature Tr reaches the first thermo-off temperature TrdfL1 or less continuously for a predetermined time tL in step ST22. When it is determined in step ST23, the compressor 21 is stopped to stop the circulation of the refrigerant and to stop the operation of the dehumidifying operation (thermo-off). Further, the control unit 6 performs the thermo-off also when it is determined in step ST27 (described later) that the room temperature Tr reaches the second thermo-off temperature TrdfL2 or less and the thermo-off condition is satisfied.

-Step ST24 (Determination of Whether the Thermo-On Condition is Met)-
During the thermo-off of step ST23, the control unit 6 determines whether or not the thermo-on condition is satisfied in step ST24.

  The control unit 6 has a thermo-on temperature condition based on the indoor temperature Tr as a determination element for determining whether the thermo-on condition is satisfied, as in step ST4 during the cooling operation. Then, the control unit 6 determines that the thermo-on condition is satisfied when the thermo-on temperature condition is satisfied, and determines that the thermo-on condition is not satisfied when the thermo-on temperature condition is not satisfied. Specifically, the control unit 6 determines that the indoor temperature Tr satisfies the thermal on temperature condition when the indoor temperature Tr becomes higher than the thermal on temperature TrdnL during the thermal off, and the indoor temperature Tr is the thermal on temperature When the temperature is lower than TrdnL, it is determined that the thermo-on temperature condition is not satisfied. The thermo-on temperature TrdnL is a value obtained by adding the thermo-on temperature difference ΔTrdnL to the target indoor temperature Trs. The thermo-on temperature difference ΔTrdnL may be the same value as the thermo-on temperature Trcn during the cooling operation (= the target indoor temperature Trs + the thermo-on temperature difference ΔTrcn), or may be a low value.

  Here, whether or not the thermo-on condition is satisfied is determined based on whether or not the room temperature Tr has reached the thermo-on temperature TrdnL, but it is not limited to this. For example, it may be determined based on whether the temperature difference ΔTr obtained by subtracting the target indoor temperature Trs from the indoor temperature Tr has reached the thermo-on temperature difference ΔTrdnL, and the indoor temperature Tr has reached the thermo-on temperature TrdnL. It is the same as judging whether you

  Then, when it is determined that the thermo-on condition is satisfied in step ST24, the control unit 6 returns to step ST21, starts the compressor 21, and performs the dehumidifying operation (thermo-on).

-Step ST25 (Determination 2 of whether the thermo-off condition is satisfied)-
When the thermo-off condition (both the first thermo-off temperature condition and the thermo-off humidity condition) of step ST22 is not satisfied during the thermo-on of step ST21, the control unit 6 satisfies the first thermo-off temperature condition in step ST25. It is determined whether the humidity condition is not satisfied. That is, when the first thermo-off temperature condition is satisfied, the control unit 6 determines whether the thermo-off humidity condition is not satisfied. Then, when the first thermo-off temperature condition is satisfied and the thermo-off humidity condition is not satisfied, the control unit 6 performs the dehumidification continuation control of step ST26 without performing the thermo-off.

-Step ST26 (Thermo-on, continuous dehumidification control)-
In step ST26, the control unit 6 continues the capacity control for controlling the capacity of the compressor 21 and the air volume control of the indoor fan 32 so that the evaporation temperature Te of the refrigerant in the refrigerant circuit 10 becomes the target evaporation temperature Teds. However, here, unlike the capacity control and air flow control of step ST21, the controller 6 sets the capacity of the compressor 21 such that the evaporation temperature Te of the refrigerant in the indoor heat exchanger 31 falls below the dew point temperature Trw of the room air. And control the air volume of the indoor fan 32. Here, the air volume of the indoor fan 32 is controlled to the minimum air volume LL, and control is performed to reduce the capacity of the compressor 21 in the range where the evaporation temperature Te falls below the dew point temperature Trw.

  Here, the control unit 6 determines the target evaporation temperature Teds based on the dew point temperature Trw. Specifically, the control unit 6 calculates the dew point temperature Trw from the indoor temperature Tr and the indoor humidity Hr. Then, the control unit 6 subtracts the predetermined temperature difference ΔTrw from the calculated dew point temperature Trw to determine the target evaporation temperature Teds. That is, the control unit 6 determines the target evaporation temperature Teds to be lower than the dew point temperature Trw.

  Then, the room dehumidification is continued by such dehumidification continuation control, and when the room humidity Hr reaches the target room humidity HrsL, the control unit 6 performs both the first thermo-off temperature condition and the thermo-off humidity condition in step ST22. It is determined that the thermo-off condition is satisfied by satisfying the above, and the thermo-off is performed in step ST23.

-Step ST27 (Determination 3 of Whether the Thermo-off Condition is Satisfied)-
If the thermo-off condition (both the first thermo-off temperature condition and the thermo-off humidity condition) of step ST22 is not satisfied during the dehumidification continuation control of step ST26, the control unit 6 does not satisfy the thermo-off humidity condition in step ST27. It is determined whether the thermo-off condition is satisfied by satisfying the second thermo-off temperature condition.

  The control unit 6 further includes a second thermo-off temperature condition on the lower temperature side than the first thermo-off temperature condition as a determination element that determines whether the thermo-off condition is satisfied. Then, the control unit 6 determines that the thermo-off condition is satisfied when the second thermo-off temperature condition is satisfied even if the thermo-off humidity condition is not satisfied, and the thermo-off humidity condition and the second thermo-off temperature condition are not satisfied. It is determined that the thermo-off condition is not satisfied. That is, during the dehumidification continuation control of step ST26, in step ST22, not only it is determined whether both the first thermo-off temperature condition and the thermo-off humidity condition are satisfied, it is also determined whether the second thermo-off temperature condition is satisfied. ing.

  Specifically, the control unit 6 determines that the second thermo-off temperature condition is satisfied when the room temperature Tr is further lowered during the dehumidification continuation control and the room temperature Tr reaches the second thermo-off temperature TrdfL2 or less. When the room temperature Tr is higher than the second thermo-off temperature TrdfL2, it is determined that the second thermo-off temperature condition is not satisfied. Here, the second thermo-off temperature TrdfL2 is a value obtained by adding the second thermo-off temperature difference ΔTrdfL2 to the target indoor temperature Trs. Then, the second thermo-off temperature difference ΔTrdfL2 is set to a value (for example, a value of about -3 degrees to -2 degrees) lower than the first thermo-off temperature TrdfL1.

  Here, whether or not the thermo-off condition is satisfied is determined based on whether or not the room temperature Tr has reached the second thermo-off temperature TrdfL2. However, the present invention is not limited to this. For example, it may be determined based on whether the temperature difference ΔTr obtained by subtracting the target indoor temperature Trs from the indoor temperature Tr has reached the second thermo-off temperature difference ΔTrdfL2. The determination based on the temperature difference ΔTr is also the same as the determination based on whether the room temperature Tr has reached the second thermo-off temperature TrdfL2.

<Step ST13 (Dehumidifying Operation Mode M)>
When the dehumidifying operation mode M is selected in step ST11, the control unit 6 controls step ST13 (that is, steps ST31 to ST37).

  Here, the process of steps ST31 to ST37 of the dehumidifying operation mode M is the same as the process of steps ST21 to ST27 of the dehumidifying operation mode L. For this reason, here, the letter “L” in the description of steps ST21 to ST27 in the dehumidifying operation mode L is replaced with “M”, and steps ST21 to ST27 are replaced with ST31 to ST37 to explain steps ST31 to ST37. Omitted.

  However, with regard to the target indoor humidity HrsM, when the dehumidifying operation mode M is selected in step ST11, a value (for example, a moderate relative humidity of about 50% to 60%) lower than the target indoor humidity HrsL of the dehumidifying operating mode L Value).

  In the dehumidifying operation mode M, the first thermo-off temperature TrdfM1 (first thermo-off temperature difference ΔTrdfM1) may be set to the same value as the first thermo-off temperature TrdfL1 (first thermo-off temperature difference ΔTrdfL1) in the dehumidifying operation mode L. The first thermo-off temperature difference ΔTrdfM1 may have a low value (for example, a value of about −1.5 degrees to +0.5 degrees). The predetermined time tM may be the same value as the predetermined time tL in the dehumidifying operation mode L, but may be a long value. The thermo-on temperature TrdnM (= target indoor temperature Trs + thermo-on temperature difference Δ Trd nM) may be the same value as the thermo-on temperature Trdn L (= target indoor temperature Trs + thermo-on temperature difference Δ Trdn L) in the dehumidifying operation mode L, but may be a low value . The second thermo-off temperature TrdfM2 (= target indoor temperature Trs + second thermo-off temperature difference ΔTrdfM2) may be set to the same value as the second thermo-off temperature TrdfL2 (= target indoor temperature Trs + second thermo-off temperature difference ΔTrdfL2) in the dehumidifying operation mode L However, it may be a low value (for example, the second thermo-off temperature difference ΔTrdfM2 is a value of about -3.5 degrees to -2.5 degrees).

<Step ST14 (Dehumidifying Operation Mode H)>
When the dehumidifying operation mode H is selected in step ST11, the control unit 6 controls step ST14 (that is, steps ST41 to ST47).

  Here, the process of steps ST41 to ST47 of the dehumidifying operation mode H is the same as the process of steps ST21 to ST27 of the dehumidifying operation mode L. Therefore, in this case, the letter "L" in the description of steps ST21 to ST27 in the dehumidifying operation mode L is read as "H", and the steps ST21 to ST27 are read as ST41 to ST47, thereby explaining the steps ST41 to ST47. Omitted.

  However, as for the target indoor humidity HrsH, when the dehumidifying operation mode H is selected in step ST11, a value lower than the target indoor humidity HrsL, HrsM of the dehumidifying operating mode L, M (for example, about 40% to 50% lower) The relative humidity value of) is set.

  Further, in the dehumidifying operation mode H, the first thermo-off temperature TrdfH1 (first thermo-off temperature difference ΔTrdfH1) is the same as the first thermo-off temperature TrdfL1, TrdfM1 (first thermo-off temperature difference ΔTrdfL1, ΔTrdfM1) in the dehumidifying operation mode L, M. It may be a value, but may be a low value (for example, the first thermo-off temperature difference ΔTrdfH1 is a value of about −2 degrees to 0 degrees). The predetermined time tH may be the same value as the predetermined time tL, tM in the dehumidifying operation modes L, M, but may be a long value. The thermo-on temperature TrdnH (= target indoor temperature Trs + thermo-on temperature difference ΔTrdnH) may be the same value as the thermo-on temperature TrdnL, TrdnM (= target indoor temperature Trs + thermo-on temperature difference ΔTrdnL, ΔTrdnM) in the dehumidifying operation mode L, M. It may be a low value. The second thermo-off temperature TrdfH2 (= target indoor temperature Trs + second thermo-off temperature difference ΔTrdfH2), the second thermo-off temperature TrdfL2, TrdfM2 (= target indoor temperature Trs + second thermo-off temperature difference ΔTrdfL2, ΔTrdfM2) in the dehumidifying operation mode L, M The same value may be used, but a low value (for example, the second thermo-off temperature difference ΔTrdfH2 may have a value of about -4 degrees to -3 degrees).

(6) Characteristics Next, the characteristics of the air conditioner 1 will be described.

<A>
In the air conditioning apparatus 1 that performs the dehumidifying operation, even during the dehumidifying operation, the indoor temperature Tr approaches the target indoor temperature Trs and the indoor temperature Tr is the thermo-off temperature as in the cooling operation (processing of steps ST1 to ST4). If the thermo-off is performed when the temperature reaches the value, the room is not sufficiently dehumidified, and there is a possibility that the occupant feels uncomfortable due to insufficient dehumidification in the room. In particular, in a transient operation state where the target indoor temperature Trs is set high and the dehumidifying operation is started, the thermo-off is performed immediately after the start of the dehumidifying operation, and the dehumidifying deficiency in the room occurs. It tends to be easy. In addition, since the temperature in the indoor heat exchanger 31 rises during the thermo-off, the condensed water may be re-evaporated, and the indoor humidity Hr may be increased.

  Therefore, here, as described above, when the control unit 6 satisfies the first thermo-off temperature condition (thermo-off temperature condition), the refrigerant in the indoor heat exchanger 31 is not performed without performing the thermo-off for stopping the compressor 21. The capacity of the compressor 21 and the air volume of the indoor fan 32 are controlled such that the evaporation temperature Te of the air flow falls below the dew point temperature Trw of the room air (dehumidification continuation control, see steps ST26, ST36, and ST46).

  Thereby, the room dehumidification can be continued in the state where condensation of indoor air occurs surely in the indoor heat exchanger 31. For this reason, when the thermo-off temperature condition is satisfied, the amount of dehumidification can be increased as compared to the case where the thermo-off is performed, and the possibility that the person in the room feels uncomfortable due to the lack of dehumidification in the room can be reduced.

  In particular, here, the control unit 6 controls the air volume of the indoor fan 32 to the minimum air volume LL and performs control to reduce the capacity of the compressor 21 in the range where the evaporation temperature Te falls below the dew point temperature Trw.

  Thus, the heat exchange between the refrigerant and the indoor air can be suppressed by reducing the flow rate of the refrigerant performing heat exchange in the indoor heat exchanger 31 and the air volume of the indoor air. For this reason, it is possible to suppress a decrease in the room temperature Tr, and to reduce the possibility that the room temperature Tr may be too low and the occupant may feel uncomfortable.

<B>
Here, as described above, the control unit 6 is configured to be able to select a plurality of dehumidifying operation modes having different dehumidifying levels as the dehumidifying operation (see steps ST11 to ST14).

  Thereby, the dehumidification driving | operation suitable for the needs of a person's room with a dehumidification level can be performed here.

<C>
Here, as described above, the control unit 6 changes the first thermo-off temperature condition (thermo-off temperature condition) to a lower temperature side as the dehumidifying level of the selected dehumidifying operation mode is higher (step ST22) See ST32, ST42, ST25, ST35, and ST45). Specifically, the thermo-off temperature difference is reduced in the order of the dehumidifying operation modes L, M and H (that is, ΔTrdfL1>ΔTrdfM1> ΔTrdfH1), whereby the thermo-off temperatures in the dehumidifying operating mode L, M and H are in order. To a low value (ie, TrdfL1>TrdfM1> TrdfH1).

  As a result, the higher the dehumidification level is, the harder it is to meet the thermo-off temperature condition, and the amount of dehumidification can be increased until the thermo-off temperature condition is satisfied.

  Here, the control unit 6 may change the thermo-off temperature condition during the dehumidifying operation to a temperature lower than the thermo-off temperature condition during the cooling operation. Specifically, the thermo-off temperature differences ΔTrdfL1, ΔTrdfM1, and ΔTrdfH1 during the dehumidifying operation are set to values lower than the thermo-off temperature difference ΔTrcf during the cooling operation. Thereby, the room can be dehumidified more than in the cooling operation.

<D>
However, there is a possibility that room temperature Tr may become too low by continuation of dehumidification after satisfying the above 1st thermo-off temperature conditions (thermo-off temperature conditions). For example, it is a case where thermo-off humidity conditions are not satisfied also by continuation of dehumidification after meeting thermo-off temperature conditions. In such a case, the room temperature Tr may be too low and the occupant may feel uncomfortable.

  Therefore, here, as described above, as a determination element for determining whether or not the thermo-off condition is satisfied, the control unit 6 further sets the second thermo-off temperature condition on the lower temperature side than the first thermo-off temperature condition (thermo-off temperature condition). Have. Then, even if the thermo-off humidity condition is not satisfied, the control unit 6 determines that the thermo-off condition is satisfied if the second thermo-off temperature condition on the low temperature side is satisfied (see steps ST27, ST37, and ST47). .

  Thereby, by continuing the dehumidification after satisfying the first thermo-off temperature condition, thermo-off can be performed before the indoor temperature Tr becomes too low (see steps ST23, ST33, and ST43). For this reason, the amount of dehumidification is increased by continuing dehumidification after satisfying the first thermo-off temperature condition, thereby reducing the possibility that the occupant feels uncomfortable due to insufficient dehumidification in the room and satisfying the first thermo-off temperature condition. Excessive continuation of dehumidification afterward can be suppressed, and the possibility that the occupant feels uncomfortable can be reduced because the room temperature Tr becomes too low.

<E>
Here, as described above, when the control unit 6 reaches the second thermo-off temperatures TrdfL2, TrdfM2, TrdfH2 whose room temperature Tr is lower than the first thermo-off temperatures TrdfL1, TrdfM1, TrdfH1, the second thermo-off temperature It is determined that the condition is satisfied (see steps ST27, ST37 and ST47).

  As a result, here, the thermo-off is performed when the room temperature Tr reaches the second thermo-off temperatures TrdfL2, TrdfM2, TrdfH2, so that the possibility of the room temperature Tr becoming too low can be reduced.

<F>
Here, as described above, as the dehumidifying level of the selected dehumidifying operation mode is higher, the control unit 6 changes the second thermo-off temperature condition to a lower temperature side (see steps ST27, ST37, and ST47). . Specifically, the second thermo-off temperature difference is reduced in the order of the dehumidifying operation modes L, M and H (that is, ΔTrdfL2>ΔTrdfM2> ΔTrdfH2), whereby the dehumidifying operating modes L, M and H are in the order of The second thermo-off temperature is set to a low value (ie, TrdfL2>TrdfM2> TrdfH2).

  Thereby, since it becomes difficult to satisfy | fill 2nd thermo-off temperature conditions here so that a dehumidification level becomes high, the dehumidification amount until it satisfy | fills 2nd thermo-off temperature conditions can be increased.

<G>
Here, as described above, when the control unit 6 continues the state in which the room temperature Tr has reached the first thermo-off temperatures TrdfL1, TrdfM1, TrdfH1 for a predetermined time tL, tM, tH, the first It is determined that the thermo-off temperature condition is satisfied (see steps ST22, ST32, ST42, ST25, ST35, and ST45).

  Here, as compared with the case where it is determined that the first thermo-off temperature condition is satisfied when the room temperature Tr reaches the first thermo-off temperature TrdfL1, TrdfM1, TrdfH1, the time until the first thermo-off temperature condition is satisfied, The amount of dehumidification can be increased. In addition, it is possible to prevent an erroneous determination as to whether or not the first thermo-off temperature condition is satisfied.

  Here, as the dehumidification level of the selected dehumidification operation mode is higher, the control unit 6 may lengthen the predetermined time (see steps ST22, ST32, ST42, ST25, ST35, and ST45). Specifically, the predetermined time is set to a long value in the order of the dehumidifying operation modes L, M and H (set tL <tM <tH).

  Thereby, since it becomes difficult to satisfy | fill 1st thermo-off temperature conditions here so that a dehumidification level becomes high, the dehumidification amount until it satisfy | fills 1st thermo-off temperature conditions can be increased.

(7) Modifications <A>
In the above embodiment, in the dehumidifying continuation control in steps ST26, ST36, and ST46, the control unit 6 performs control to reduce the capacity of the compressor 21 in the range where the evaporation temperature Te falls below the dew point temperature Trw. Specifically, the control unit 6 determines the target evaporation temperature Teds by subtracting the predetermined temperature difference ΔTrw from the dew point temperature Trw, and the capacity of the compressor 21 is set such that the evaporation temperature Te becomes the target evaporation temperature Teds. I have control.

  However, when the target evaporation temperature Teds is set to a lower value in the capacity control of the compressor 21, the capacity of the compressor 21 is controlled to be larger, and not only dehumidification of the room is promoted, but also the room The temperature Tr also tends to decrease.

  Therefore, in this case, in the dehumidification continuation control of steps ST26, ST36, and ST46, control is performed to reduce the capacity of the compressor 21 until it is determined that the room temperature Tr is rising.

  Specifically, as shown in FIG. 8, the control unit 6 changes the predetermined temperature difference ΔTrw to be smaller in step ST52 until it is determined in step ST51 that the room temperature Tr is rising. Thus, the capacity control of the compressor 21 is performed such that the target evaporation temperature Teds becomes higher in the range below the dew point temperature Trw.

  Hereby, the flow rate of the refrigerant performing heat exchange in the indoor heat exchanger 31 can be reduced to the flow rate at which dehumidification can be performed without lowering the room temperature Tr, and the occupant may feel uncomfortable. It can be further reduced. Also, the frequency of thermo-off can be reduced.

<B>
In the above embodiment and modification A, in the dehumidifying continuation control in steps ST26, ST36, and ST46, the control unit 6 performs control to reduce the capacity of the compressor 21 in the range where the evaporation temperature Te falls below the dew point temperature Trw. ing. Specifically, the control unit 6 determines the target evaporation temperature Teds by subtracting the predetermined temperature difference ΔTrw from the dew point temperature Trw, and the capacity of the compressor 21 is set such that the evaporation temperature Te becomes the target evaporation temperature Teds. I have control.

  However, if the target evaporation temperature Teds is set to be low, indoor air may be excessively cooled in the indoor heat exchanger 31, and in the vicinity of the outlet 46 of the indoor unit 3 that houses the indoor heat exchanger 31, Condensation may occur.

  Therefore, here, in the dehumidification continuation control in steps ST26, ST36, ST46, the control unit 6 performs control to reduce the capacity of the compressor 21 within a range equal to or higher than the lower limit value Tem of the evaporation temperature Te.

  Specifically, as shown in FIG. 9, the control unit 6 first determines the lower limit value Tem from the room temperature Tr and the room humidity Hr in step ST53. Here, the lower limit value Tem is determined in view of whether condensation does not occur in the vicinity of the outlet 46 of the indoor unit 3 regardless of how low the evaporation temperature Te is viewed from the indoor temperature Tr and the indoor humidity Hr. Ru. For this reason, when the room temperature Tr is low or the room humidity Hr is low, dew condensation hardly occurs, so the lower limit Tem is determined to be low, and the room temperature Tr is high, Further, when the indoor humidity Hr is high, dew condensation is likely to occur, so the lower limit value Tem is determined to be high. Next, in step ST54, the control unit 6 determines whether the target evaporation temperature Teds is equal to or higher than the lower limit value Tem. Then, when it is determined in step ST54 that the target evaporation temperature Teds is not the lower limit value Tem or more, the control unit 6 performs the change to reduce the predetermined temperature difference ΔTrw in step ST55, whereby the target evaporation temperature Teds is smaller. The displacement control of the compressor 21 is performed so as to increase in a range below the dew point temperature Trw.

  Thus, here, by performing control to reduce the capacity of the compressor 21 within the range of the lower limit value Tem or more of the evaporation temperature Te, the indoor heat is excessively cooled in the indoor heat exchanger 31, so that the room In the vicinity of the outlet 46 of the unit 3, the risk of dew condensation can be reduced.

  Further, when the dehumidifying operation is performed, the dehumidification in the room advances and the indoor humidity Hr gradually decreases, so that the possibility of dew condensation in the vicinity of the outlet 46 of the indoor unit 3 tends to be gradually reduced. Here, since the control unit 6 determines the lower limit value Tem from the room temperature Tr and the room humidity Hr in step ST53, the lower limit value Tem becomes low during the dehumidification continuation control. That is, here, the control unit 6 lowers the lower limit value Tem of the evaporation temperature Te during the dehumidifying operation.

  Thereby, the range which lowers evaporation temperature Te can be expanded here, and evaporation temperature Te can be made to certainly fall below dew point temperature Trw. In particular, here, the range in which the evaporation temperature Te is reduced can be expanded in consideration of the indoor temperature Tr and the indoor humidity Hr, so that the occurrence of condensation can be suppressed as much as possible.

<C>
In the above embodiment and Modifications A and B, three of the dehumidifying operation modes L, M and H can be selected as a plurality of dehumidifying operation modes having different dehumidifying levels, but the present invention is not limited thereto. Alternatively, two dehumidification operating modes may be used, or four or more dehumidifying operating modes may be used.

<D>
In the said embodiment and modification AC, although the example which employ | adopted the ceiling embedded type was demonstrated as the indoor unit 3 which accommodates the indoor heat exchanger 31, it is not limited to this, It may be another type of indoor unit such as a wall-mounted type.

  While the embodiments of the present disclosure have been described above, it will be understood that various changes in form and detail can be made without departing from the spirit and scope of the present disclosure as set forth in the claims. .

  The present disclosure is widely applicable to an air conditioner performing a dehumidifying operation.

DESCRIPTION OF SYMBOLS 1 Air conditioning apparatus 6 Control part 10 Refrigerant circuit 21 Compressor 24 Outdoor heat exchanger 25 Expansion valve (expansion mechanism)
31 indoor heat exchanger 32 indoor fan

JP 2004-76973 A

  Air conditioner for dehumidifying operation

  BACKGROUND Conventionally, there is an air conditioner having a refrigerant circuit configured by connecting a compressor, an outdoor heat exchanger, an expansion mechanism, and an indoor heat exchanger. Then, in this air conditioning apparatus, a dehumidifying operation may be performed in which the refrigerant sealed in the refrigerant circuit is circulated in the order of the compressor, the outdoor heat exchanger, the expansion mechanism, and the indoor heat exchanger. During the dehumidifying operation, as shown in Patent Document 1 (Japanese Patent Laid-Open No. 2004-76973), when the room temperature reaches the target room temperature, the thermo-off is performed to stop the compressor.

  In the air conditioner of Patent Document 1, as described above, when the room temperature reaches the target room temperature during the dehumidifying operation, it is determined that the thermo-off condition is satisfied, and the thermo-off is performed.

  However, in such a dehumidifying operation, the room temperature may reach the target room temperature without sufficient room dehumidification, and the thermo-off may be performed. There is a risk of

An air conditioner according to a first aspect includes a refrigerant circuit, an indoor fan, and a control unit. The refrigerant circuit is configured by connecting a compressor, an outdoor heat exchanger, an expansion mechanism, and an indoor heat exchanger. The indoor fan sends indoor air to the indoor heat exchanger. The control unit performs the dehumidifying operation in which the refrigerant sealed in the refrigerant circuit is circulated in the order of the compressor, the outdoor heat exchanger, the expansion mechanism, and the indoor heat exchanger. The control unit is configured to stop the compressor when a predetermined thermo-off condition is satisfied during the dehumidifying operation, and the control unit is configured to determine whether the thermo-off condition is satisfied or not, and the thermo-off based on the room temperature There are temperature conditions and thermo-off humidity conditions due to room humidity. The control unit performs an indoor heat exchanger without stopping the compressor when the indoor temperature satisfies the thermo-off temperature condition if the thermo-off humidity condition is not satisfied when the thermo-off temperature condition is satisfied during the dehumidifying operation. The capacity of the compressor and the air volume of the indoor fan are controlled so that the evaporation temperature of the refrigerant is lower than the dew point temperature of the indoor air.

  Here, even if the thermo-off temperature condition is satisfied, thermo-off is not performed, and the room dehumidification is continued in a state where condensation of the room air reliably occurs in the indoor heat exchanger. For this reason, when the thermo-off temperature condition is satisfied, the amount of dehumidification can be increased as compared to the case where the thermo-off is performed, and the possibility that the person in the room feels uncomfortable due to the lack of dehumidification in the room can be reduced.

  In the air conditioner according to the second aspect, in the air conditioner according to the first aspect, the control unit controls the air volume of the indoor fan to the minimum air volume, and the evaporation temperature of the compressor falls below the dew point temperature Control to make it smaller in the range.

  Here, the flow rate of the refrigerant that performs heat exchange in the indoor heat exchanger and the air volume of the indoor air can be reduced, so that the heat exchange between the refrigerant and the indoor air can be suppressed. It is possible to reduce the possibility that the room temperature may be too low and the occupant may feel uncomfortable.

  The air conditioning apparatus according to the third aspect is the air conditioning apparatus according to the second aspect, wherein the control unit performs control to reduce the capacity of the compressor until the indoor temperature rises.

  Here, by reducing the flow rate of the refrigerant performing heat exchange in the indoor heat exchanger to a flow rate at which dehumidification can be performed without lowering the room temperature, the possibility of discomfort for the occupant can be further reduced. .

  In the air conditioner according to the fourth aspect, in the air conditioner according to the second or third aspect, the control unit performs control to reduce the capacity of the compressor within a range equal to or higher than the lower limit value of the evaporation temperature.

  Here, by excessively cooling the indoor air in the indoor heat exchanger, it is possible to reduce the possibility of the occurrence of condensation in the vicinity of the outlet of the indoor unit that accommodates the indoor heat exchanger.

  The air conditioning apparatus according to a fifth aspect is the air conditioning apparatus according to the fourth aspect, wherein the control unit lowers the lower limit value of the evaporation temperature during the dehumidifying operation.

  Here, the range in which the evaporation temperature is lowered can be expanded, and the evaporation temperature can be made to surely fall below the dew point temperature.

  The air conditioning apparatus according to a sixth aspect is the air conditioning apparatus according to the fifth aspect, wherein the control unit determines the lower limit value of the evaporation temperature from the room temperature and the room humidity.

  Here, since the range in which the evaporation temperature is lowered can be expanded in consideration of the room temperature and the room humidity, the occurrence of condensation can be suppressed as much as possible.

  An air conditioning apparatus according to a seventh aspect is the air conditioning apparatus according to any of the first to sixth aspects, wherein the control unit is configured to be able to select a plurality of dehumidifying operation modes having different dehumidifying levels as the dehumidifying operation. Has been.

  Here, the dehumidifying operation suitable for the dehumidifying level needs of the occupant can be performed.

  The air conditioning apparatus according to an eighth aspect is the air conditioning apparatus according to the seventh aspect, wherein the control unit changes the thermo-off temperature condition to a lower temperature side as the dehumidifying level in the selected dehumidifying operation mode is higher.

  Here, the higher the dehumidification level is, the harder it is to satisfy the first thermo-off temperature condition, so the dehumidification amount can be increased until the first thermo-off temperature condition is satisfied.

It is a schematic block diagram of the air conditioning apparatus concerning one embodiment of this indication. It is an external appearance perspective view of the indoor unit which comprises an air conditioning apparatus. It is a schematic side surface sectional view of an indoor unit, and is an IO I sectional view of FIG. It is a control block diagram of an air conditioning apparatus. It is a control flowchart at the time of air conditioning operation. It is a control flowchart (mode selection) at the time of dehumidification operation. It is a control flowchart (dehumidification operation mode L, M, H) at the time of dehumidification operation. It is a flow chart which shows dehumidification continuation control in modification A. It is a flowchart which shows the dehumidification continuation control in the modification B. FIG.

  Hereinafter, embodiments of the air conditioner will be described based on the drawings.

(1) Device Configuration FIG. 1 is a schematic configuration diagram of an air conditioner 1 according to an embodiment of the present disclosure.

<Overall>
The air conditioning apparatus 1 is an apparatus that performs air conditioning in a room such as a building by a vapor compression refrigeration cycle. The air conditioner 1 mainly includes an outdoor unit 2, an indoor unit 3, and a liquid refrigerant communication pipe 4 and a gas refrigerant communication pipe 5 that connect the outdoor unit 2 and the indoor unit 3. The vapor compression type refrigerant circuit 10 of the air conditioner 1 is configured by connecting the outdoor unit 2 and the indoor unit 3 via the liquid refrigerant communication pipe 4 and the gas refrigerant communication pipe 5.

<Outdoor unit>
The outdoor unit 2 is installed outdoors (in the vicinity of the roof of a building, the outer wall of a building, etc.). The outdoor unit 2 is connected to the indoor unit 3 via the liquid refrigerant communication pipe 4 and the gas refrigerant communication pipe 5 as described above, and constitutes a part of the refrigerant circuit 10. The outdoor unit 2 mainly includes a compressor 21, a four-way switching valve 23, an outdoor heat exchanger 24, and an expansion valve 25.

  The compressor 21 is a mechanism that compresses low-pressure refrigerant in the refrigeration cycle to high pressure. Here, as the compressor 21, a compressor of a closed type in which a rotary or scroll type positive displacement type compression element (not shown) is rotationally driven by the compressor motor 22 is used. Further, in this case, the compressor motor 22 can be controlled in rotation speed (frequency) by an inverter or the like, whereby the capacity of the compressor 21 can be controlled.

  The four-way switching valve 23 is a valve for switching the flow direction of the refrigerant when switching between the cooling operation or the dehumidifying operation and the heating operation. The four-way switching valve 23 connects the discharge side of the compressor 21 and the gas side of the outdoor heat exchanger 24 during the cooling operation or the dehumidifying operation, and also connects the indoor heat exchanger 31 (described later) via the gas refrigerant communication pipe 5. Can be connected to the suction side of the compressor 21 (see the solid line of the four-way switching valve 23 in FIG. 1). Further, the four-way switching valve 23 connects the discharge side of the compressor 21 and the gas side of the indoor heat exchanger 31 via the gas refrigerant communication pipe 5 during the heating operation, and the gas side of the outdoor heat exchanger 24 And the suction side of the compressor 21 (see the broken line of the four-way switching valve 23 in FIG. 1).

  The outdoor heat exchanger 24 is a heat exchanger that functions as a radiator of the refrigerant during the cooling operation or the dehumidifying operation, and functions as an evaporator of the refrigerant during the heating operation. The liquid side of the outdoor heat exchanger 24 is connected to the expansion valve 25, and the gas side is connected to the four-way switching valve 23.

  The expansion valve 25 reduces the pressure of the high pressure liquid refrigerant released in the outdoor heat exchanger 24 during the cooling operation or the dehumidifying operation before sending it to the indoor heat exchanger 31, and the high pressure liquid released in the indoor heat exchanger 31 during the heating operation. This is an expansion mechanism capable of reducing the pressure before sending the refrigerant to the outdoor heat exchanger 24. Here, an electric expansion valve capable of controlling the degree of opening is used as the expansion valve 25.

  In addition, the outdoor unit 2 is provided with an outdoor fan 26 for drawing outdoor air into the unit and supplying the outdoor air to the outdoor heat exchanger 24 and discharging the outdoor air to the outside of the unit. That is, the outdoor heat exchanger 24 is a heat exchanger that radiates or evaporates the refrigerant using the outdoor air as a cooling source or a heating source. The outdoor fan 26 is rotationally driven by the outdoor fan motor 27.

  In addition, the outdoor unit 2 is provided with various sensors. Specifically, the outdoor unit 2 is provided with a suction pressure sensor 28 that detects the suction pressure Ps of the compressor 21.

<Refrigerant communication tube>
The refrigerant communication pipes 4 and 5 are refrigerant pipes that are constructed on site when the air conditioning apparatus 1 is installed at an installation place such as a building. One end of the liquid refrigerant communication pipe 4 is connected to the expansion valve 25 side of the indoor unit 2, and the other end of the liquid refrigerant communication pipe 4 is connected to the liquid side of the indoor heat exchanger 31 of the indoor unit 3. One end of the gas refrigerant communication pipe 5 is connected to the four-way switching valve 23 side of the indoor unit 2, and the other end of the gas refrigerant communication pipe 5 is connected to the gas side of the indoor heat exchanger 31 of the indoor unit 3. .

<Indoor unit>
The indoor unit 3 is installed indoors (within a building). As described above, the indoor unit 3 is connected to the outdoor unit 2 via the liquid refrigerant communication pipe 4 and the gas refrigerant communication pipe 5, and constitutes a part of the refrigerant circuit 10. The indoor unit 3 mainly includes an indoor heat exchanger 31 and an indoor fan 32.

  Here, as the indoor unit 3, an indoor unit of a type called a ceiling-embedded type is adopted. As shown in FIGS. 2 and 3, the indoor unit 3 has a casing 41 for housing the components therein. The casing 41 is composed of a casing body 41 a and a decorative panel 42 disposed below the casing body 41 a. The casing main body 41a is inserted into an opening formed in the ceiling U and disposed as shown in FIG. And, the decorative panel 42 is arranged to be fitted into the opening of the ceiling U. Here, FIG. 2 is an external perspective view of the indoor unit 3. FIG. 3 is a schematic side cross-sectional view of the indoor unit 3 and is an IO-I cross-sectional view of FIG. 2.

  The casing main body 41a is a substantially octagonal box-like body in which long sides and short sides are alternately formed in a plan view, and the lower surface is open. The casing main body 41 a has a substantially octagonal top plate 43 in which long sides and short sides are alternately and continuously formed, and a side plate 44 extending downward from the peripheral portion of the top plate 43.

  The decorative panel 42 is a plate-like body having a substantially polygonal shape (here, substantially rectangular shape) in plan view constituting the lower surface of the casing 41, and is mainly a panel body fixed to the lower end of the casing body 41a. 42a. The panel main body 42a has a suction port 45 for sucking air in the room and a blowoff port 46 for blowing air into the room formed so as to surround the circumference of the suction port 45 in plan view. The suction port 45 is a substantially rectangular opening. The suction port 45 is provided with a suction grill 47 and a suction filter 48 for removing dust in the air sucked from the suction port 45. The outlets 46 are a plurality of (here, four) side outlets 46a formed along each side of the square of the panel body 42a, and a plurality (here, formed at corners of the panel body 42a). In the above, four (4) corner air outlets 46b are provided. And in each side part outlet 46a, there are a plurality of (here, four) wind direction changing blades 49 capable of changing the wind direction angle of the air blown out into the room from each side part outlet. It is provided. The wind direction changing blade 49 is a plate-like member elongated in the longitudinal direction of the side air outlet 46a. The wind direction changing blade 49 can be turned around the longitudinal axis to change the wind direction angle in the vertical direction.

  The indoor heat exchanger 31 and the indoor fan 32 are mainly disposed inside the casing main body 41a.

  The indoor heat exchanger 31 is a heat exchanger that functions as an evaporator of the refrigerant during the cooling operation or the dehumidifying operation, and functions as a radiator of the refrigerant during the heating operation. The liquid side of the outdoor heat exchanger 31 is connected to the liquid refrigerant communication pipe 4, and the gas side is connected to the gas refrigerant communication pipe 5. The indoor heat exchanger 31 is a heat exchanger that is bent and disposed so as to surround the indoor fan 32 in plan view. The indoor heat exchanger 31 exchanges heat between the indoor air and the refrigerant drawn into the casing main body 41 a by the indoor fan 32. Further, below the indoor heat exchanger 31, a drain pan 31a for receiving drain water generated by condensing moisture in indoor air by the indoor heat exchanger 31 is disposed. The drain pan 31a is attached to the lower part of the casing main body 41a.

  The indoor fan 32 is a fan that sucks room air into the casing main body 41 a through the suction port 45 of the decorative panel 42 and blows it out of the casing main body 41 a into the room through the outlet 46 of the decorative panel 42. That is, the indoor heat exchanger 31 is a heat exchanger that radiates or evaporates the refrigerant by using indoor air as a cooling source or a heating source. Here, as the indoor fan 32, a centrifugal fan is used which sucks indoor air from below and blows it toward the outer peripheral side in a plan view. The indoor fan 32 is rotationally driven by an indoor fan motor 33 provided at the center of the top plate 43 of the casing main body 41a. Further, here, the indoor fan motor 33 can be controlled in rotational speed (frequency) by an inverter or the like, whereby the air volume of the indoor fan 32 can be controlled. Specifically, as the air volume of the indoor fan 32, the air volume H of the maximum air volume, the medium air volume M of the medium air volume smaller than the air volume H, the air volume L of the small air volume smaller than the air volume M, and the minimum of the air volume L Four of the air volume LL, of the air volume are prepared. Here, the air volume LL is an air volume that can not be set by the occupant by the remote control 60 (described later).

  The indoor unit 3 is provided with various sensors. Specifically, the indoor unit 3 is provided with an indoor temperature sensor 34 and an indoor humidity sensor 35 for detecting the temperature (indoor temperature Tr) and the humidity (indoor humidity Hr) of the indoor air sucked into the indoor unit 3. ing.

(2) Control Configuration FIG. 4 is a control block diagram of the air conditioner 1.

<Overall>
The air conditioner 1 as the refrigeration system has a control unit 6 in which the outdoor control unit 20, the indoor control unit 30, and the remote control 60 are connected via a transmission line or a communication line in order to perform operation control of the component devices. have. The outdoor control unit 20 is provided in the indoor unit 2. The indoor control unit 30 is provided in the indoor unit 3. The remote control 60 is provided indoors. Here, although the control units 20 and 30 and the remote control 60 are connected by wire via a transmission line or a communication line, they may be connected wirelessly.

<Outdoor control unit>
As described above, the outdoor control unit 20 is provided in the outdoor unit 2 and mainly includes the outdoor CPU 20a, the outdoor transmission unit 20b, and the outdoor storage unit 20c. The indoor control unit 20 can receive a detection signal of the suction pressure sensor 28.

  The outdoor CPU 20a is connected to the outdoor transmission unit 20b and the outdoor storage unit 20c. The heat source side transmission unit 20b transmits control data and the like with the indoor control unit 30a. The outdoor storage unit 20c stores control data and the like. Then, the outdoor CPU 20a transmits and reads control data and the like via the outdoor transmission unit 20b and the outdoor storage unit 20c, and the component devices 21, 23, 25, 26 and the like provided in the outdoor unit 2 Control the operation of

<Indoor controller>
As described above, the indoor control unit 30 is provided in the indoor unit 3 and mainly includes the indoor CPU 30a, the indoor transmission unit 30b, the indoor storage unit 30c, and the indoor communication unit 30d. Have. The indoor control unit 30 can receive detection signals from the indoor temperature sensor 34 and the indoor humidity sensor 35.

  The indoor CPU 30a is connected to the indoor transmission unit 30b, the indoor storage unit 30c, and the indoor storage unit 30d. The indoor transmission unit 30 b transmits control data and the like to and from the outdoor control unit 20. The indoor storage unit 30 b stores control data and the like. The indoor communication unit 30 c transmits and receives control data and the like to and from the remote control 60. The indoor CPU 30a transmits and reads and writes control data, etc. via the indoor transmission unit 30b, the indoor storage unit 30c, and the indoor communication unit 30d, and the component devices provided in the indoor unit 3 Perform operation control such as 32, 49.

<Remote control>
As described above, the remote control 60 is provided indoors and mainly includes the remote control CPU 61, the remote control storage unit 62, the remote control communication unit 63, the remote control operation unit 64, and the remote control display unit 65. There is.

  The remote control CPU 61 is connected to the remote control communication unit 62, the remote control storage unit 63, the remote control operation unit 64, and the remote control display unit 65. The remote control communication unit 62 transmits and receives control data and the like to and from the indoor communication unit 30c. The remote control storage unit 63 stores control data and the like. The remote control operation unit 64 receives an input such as a control command from the user. The remote control display unit 65 performs operation display and the like. Then, the remote control CPU 61 receives inputs of operation commands and control commands via the remote control operation unit 64, reads and writes control data and the like from the remote control storage unit 63, and displays the operation status and control status on the remote control display unit 65. The control command and the like are issued to the indoor control unit 30 via the remote control communication unit 62 while performing the and the like.

  As described above, the air conditioner 1 as the refrigeration system includes the control unit 6 that performs operation control of the component devices. Then, the control unit 6 controls the component devices 21, 23, 25, 26, 32, 49, etc. based on the detection signals of the suction pressure sensor 28, the indoor temperature sensor 34, the indoor humidity sensor 35, etc. It is possible to perform air conditioning operation such as dehumidifying operation and heating operation and various controls.

(3) Basic Operation Next, the basic operation (heating operation, cooling operation, and dehumidifying operation) of the air conditioner 1 will be described.

<Heating operation>
The air conditioner 1 can perform a heating operation as an air conditioning operation. In the heating operation, the control unit 6 that has received the heating operation instruction via the remote control operation unit 64 controls operation of the component devices 21, 23, 25, 26, 32, 49, etc. of the outdoor unit 2 and the outdoor unit 3. Done by

  In the heating operation, the outdoor heat exchanger 24 functions as a refrigerant evaporator and the indoor heat exchanger 31 functions as a refrigerant radiator (that is, indicated by a broken line of the four-way switching valve 23 in FIG. 1). Is switched, the four-way switching valve 23 is switched.

  In the refrigerant circuit 10 in such a state, the low-pressure refrigerant in the refrigeration cycle is drawn into the compressor 21 and compressed to a high pressure in the refrigeration cycle and then discharged. The high-pressure refrigerant discharged from the compressor 21 is sent to the indoor heat exchanger 31 through the four-way switching valve 23 and the gas refrigerant communication pipe 5. The high-pressure refrigerant sent to the indoor heat exchanger 31 exchanges heat with the indoor air supplied by the indoor fan 32 in the indoor heat exchanger 31 and radiates heat. As a result, the room air is heated and blown out into the room. The high-pressure refrigerant that has dissipated heat in the indoor heat exchanger 31 is sent to the expansion valve 25 through the liquid refrigerant communication pipe 4 and decompressed to a low pressure in the refrigeration cycle. The low-pressure refrigerant reduced in pressure by the expansion valve 25 is sent to the outdoor heat exchanger 24. The low-pressure refrigerant sent to the outdoor heat exchanger 24 exchanges heat with the outdoor air supplied by the outdoor fan 26 in the outdoor heat exchanger 24 and evaporates. The low-pressure refrigerant evaporated in the outdoor heat exchanger 24 is again sucked into the compressor 21 through the four-way switching valve 23. As described above, in the heating operation, the control unit 6 causes the refrigerant enclosed in the refrigerant circuit 10 to circulate in the order of the compressor 21, the indoor heat exchanger 31, the expansion valve 25, and the outdoor heat exchanger 24. It is supposed to be.

<Cooling operation>
The air conditioner 1 can perform the cooling operation as the air conditioning operation. In the cooling operation, the control unit 6 that has received the cooling operation command via the remote control operation unit 64 controls operation of the components 21, 23, 25, 26, 32, 49, etc. of the outdoor unit 2 and the outdoor unit 3. Done by

  In the cooling operation, the outdoor heat exchanger 24 functions as a radiator of the refrigerant, and the indoor heat exchanger 31 functions as an evaporator of the refrigerant (ie, indicated by the solid line of the four-way switching valve 23 in FIG. 1). Is switched, the four-way switching valve 23 is switched.

  In the refrigerant circuit 10 in such a state, the low-pressure refrigerant in the refrigeration cycle is drawn into the compressor 21 and compressed to a high pressure in the refrigeration cycle and then discharged. The high-pressure refrigerant discharged from the compressor 21 is sent to the outdoor heat exchanger 24 through the four-way switching valve 23. The high-pressure refrigerant sent to the outdoor heat exchanger 24 exchanges heat with the outdoor air supplied by the outdoor fan 26 in the outdoor heat exchanger 24 and radiates heat. The high-pressure refrigerant that has dissipated heat in the outdoor heat exchanger 24 is sent to the expansion valve 25 and decompressed to a low pressure in the refrigeration cycle. The low pressure refrigerant decompressed in the expansion valve 25 is sent to the indoor heat exchanger 31 through the liquid refrigerant communication pipe 4. The low-pressure refrigerant sent to the indoor heat exchanger 31 exchanges heat with the indoor air supplied by the indoor fan 32 in the indoor heat exchanger 31 to evaporate. As a result, the room air is cooled and blown out into the room. The low pressure refrigerant evaporated in the indoor heat exchanger 31 is again sucked into the compressor 21 through the gas refrigerant communication pipe 5 and the four-way switching valve 23. As described above, in the cooling operation, the control unit 6 causes the refrigerant enclosed in the refrigerant circuit 10 to circulate in the order of the compressor 21, the outdoor heat exchanger 24, the expansion valve 25, and the indoor heat exchanger 31. It is supposed to be.

<Dehumidifying operation>
The air conditioning apparatus 1 can perform the dehumidifying operation as the air conditioning operation. In the dehumidifying operation, the control unit 6 that has received the dehumidifying operation command via the remote control operation unit 64 controls the operation of the outdoor unit 2 and the components 21, 23, 26, 32, 49, etc. of the outdoor unit 3 Done by

  In the dehumidifying operation, as in the cooling operation, the outdoor heat exchanger 24 functions as a radiator of the refrigerant and the indoor heat exchanger 31 functions as an evaporator of the refrigerant (that is, the four-way switching in FIG. 1) The four-way switching valve 23 is switched so as to be in the state shown by the solid line of the valve 23).

  In the refrigerant circuit 10 in such a state, the low-pressure refrigerant in the refrigeration cycle is drawn into the compressor 21 and compressed to a high pressure in the refrigeration cycle and then discharged. The high-pressure refrigerant discharged from the compressor 21 is sent to the outdoor heat exchanger 24 through the four-way switching valve 23. The high-pressure refrigerant sent to the outdoor heat exchanger 24 exchanges heat with the outdoor air supplied by the outdoor fan 26 in the outdoor heat exchanger 24 and radiates heat. The high-pressure refrigerant that has dissipated heat in the outdoor heat exchanger 24 is sent to the expansion valve 25 and decompressed to a low pressure in the refrigeration cycle. The low pressure refrigerant decompressed in the expansion valve 25 is sent to the indoor heat exchanger 31 through the liquid refrigerant communication pipe 4. The low-pressure refrigerant sent to the indoor heat exchanger 31 exchanges heat with the indoor air supplied by the indoor fan 32 in the indoor heat exchanger 31 to evaporate. As a result, the room air is dehumidified and blown out into the room. The low pressure refrigerant evaporated in the indoor heat exchanger 31 is again sucked into the compressor 21 through the gas refrigerant communication pipe 5 and the four-way switching valve 23. As described above, in the dehumidifying operation, the control unit 6 causes the refrigerant sealed in the refrigerant circuit 10 to circulate in the order of the compressor 21, the outdoor heat exchanger 24, the expansion valve 25, and the indoor heat exchanger 31. It is supposed to be.

(4) Control in Cooling Operation In the above-described cooling operation, the following control is performed. FIG. 5 is a flowchart of the cooling operation.

<Step ST1 (Thermo-on)>
The control unit 6 performs the target evaporation temperature of the evaporation temperature Te of the refrigerant in the refrigerant circuit 10 at step ST1, that is, at the time of the cooling operation (at the time of the operation of circulating the refrigerant by operating the compressor 21). The capacity control is performed to control the capacity of the compressor 21 so as to be Tecs. In addition, the control unit 6 sets the selected air volume (here, the air volume L, the air volume selected by the room occupant by inputting the air volume of the indoor fan 32 from the remote control operation unit 64 of the remote controller 60). Control to any of M and air volume H).

  The capacity control of the compressor 21 increases the capacity of the compressor 21 by increasing the rotational speed (frequency) of the compressor 21 when the evaporation temperature Te of the refrigerant is higher than the target evaporation temperature Tecs. When the evaporation temperature Te is lower than the target evaporation temperature Tecs, the control is performed to reduce the capacity of the compressor 21 by reducing the number of revolutions (frequency) of the compressor 21.

  Here, the control unit 6 determines the target evaporation temperature Tecs based on a temperature difference ΔTr obtained by subtracting the target indoor temperature Trs from the indoor temperature Tr. Specifically, the control unit 6 determines the target evaporation temperature Tecs to be lower as the temperature difference ΔTr is larger. The target indoor temperature Trs is set by the occupant inputting from the remote control operation unit 64 of the remote control 60. Further, the evaporation temperature Te of the refrigerant can be obtained by converting the suction pressure Ps into the saturation temperature of the refrigerant. The evaporation temperature Te of the refrigerant represents the low-pressure refrigerant in the refrigeration cycle flowing from the outlet of the expansion valve 25 to the suction side of the compressor 21 via the indoor heat exchanger 31 during the cooling operation. It means the temperature obtained by converting the pressure (the evaporation pressure Pe of the refrigerant in the refrigerant circuit 10) into the saturation temperature of the refrigerant, or the saturation temperature of the refrigerant in the indoor heat exchanger 31 functioning as an evaporator of the refrigerant. Therefore, when the indoor heat exchanger 31 is provided with a temperature sensor, the temperature of the refrigerant detected by the temperature sensor may be used as the evaporation temperature Te of the refrigerant.

  In addition, although the state quantity of the control object in capacity control is made into evaporation temperature Te here, you may be evaporation pressure Pe. In this case, a target evaporation pressure Pecs corresponding to the target evaporation temperature Tecs may be used as a control target value. Using the evaporation pressure Pe and the target evaporation pressure Pecs in this volume control is also the same as using the evaporation temperature Te and the target evaporation temperature Tecs.

<Step ST2 (Determination of Whether the Thermo-off Condition is Met)>
The control unit 6 determines whether the thermo-off condition is satisfied in step ST2 during the thermo-on in step ST1.

  The control unit 6 has a thermo-off temperature condition based on the indoor temperature Tr, as a determination factor for determining whether the thermo-off condition is satisfied. Then, the control unit 6 determines that the thermo-off condition is satisfied when the thermo-off temperature condition is satisfied, and determines that the thermo-off condition is not satisfied when the thermo-off temperature condition is not satisfied. Specifically, the control unit 6 determines that the indoor temperature Tr satisfies the thermal off temperature condition when the indoor temperature Tr becomes lower than the thermal off temperature Trcf during the thermal on, and the indoor temperature Tr is the thermal off temperature If it is higher than Trcf, it is determined that the thermo-off temperature condition is not satisfied. Here, the thermo-off temperature Trcf is a value obtained by adding the thermo-off temperature difference ΔTrcf to the target indoor temperature Trs. The thermo-off temperature difference ΔTrcf is set to a value of about -1 degree to +1 degree.

  Here, whether or not the thermo-off condition is satisfied is determined by whether or not the room temperature Tr has reached the thermo-off temperature Trcf, but it is not limited to this. For example, it may be determined based on whether the temperature difference ΔTr obtained by subtracting the target indoor temperature Trs from the room temperature Tr has reached the thermo-off temperature difference ΔTrcf, and the room temperature Tr reaches the thermo-off temperature Trcf as well. It is the same as judging whether you

<Step ST3 (thermo off)>
When it is determined in step ST2 that the room temperature Tr reaches the thermo-off temperature Trcf or lower in step ST2, the controller 6 stops the compressor 21 in step ST3 to stop the circulation of the refrigerant. Stop the cooling operation (thermo-off).

<Step ST4 (Determining Whether the Thermo-On Condition is Met)>
During the thermo-off of step ST3, the control unit 6 determines whether the thermo-on condition is satisfied in step ST4.

  The control unit 6 has a thermo-on temperature condition based on the indoor temperature Tr as a determination factor for determining whether the thermo-on condition is satisfied. Then, the control unit 6 determines that the thermo-on condition is satisfied when the thermo-on temperature condition is satisfied, and determines that the thermo-on condition is not satisfied when the thermo-on temperature condition is not satisfied. Specifically, the control unit 6 determines that the indoor temperature Tr satisfies the thermal on temperature condition when the indoor temperature Tr becomes higher than the thermal on temperature Trcn during the thermal off, and the indoor temperature Tr is the thermal on temperature If the temperature is lower than Trcn, it is determined that the thermo-on temperature condition is not satisfied. Here, the thermo-on temperature Trcn is a value obtained by adding the thermo-on temperature difference ΔTrcn to the target indoor temperature Trs. The thermo-on temperature difference ΔTrcn is set to a value of about 0 degrees to +2 degrees.

  Here, whether or not the thermo-on condition is satisfied is determined based on whether or not the room temperature Tr has reached the thermo-on temperature Trcn, but it is not limited to this. For example, it may be determined based on whether the temperature difference ΔTr obtained by subtracting the target indoor temperature Trs from the indoor temperature Tr has reached the thermo-on temperature difference ΔTrcn, and the indoor temperature Tr has reached the thermo-on temperature Trcn as well. It is the same as judging whether you

  Then, if it is determined in step ST4 that the thermo-on condition is satisfied in step ST4, the control unit 6 returns to step ST1, starts the compressor 21, and performs the operation of the cooling operation (thermo-on).

(5) Control in Dehumidifying Operation In the above dehumidifying operation, the following control is performed. 6 is a flowchart (mode selection) of the dehumidifying operation, and FIG. 7 is a flowchart (dehumidifying operation mode L, M, H) of the dehumidifying operation.

<Step ST11 (mode selection)>
Here, a plurality of dehumidifying operation modes having different dehumidifying levels are prepared as the dehumidifying operation in order to meet the dehumidifying level needs of the occupants. Here, the dehumidification level means the degree of the indoor humidity Hr to be obtained by the dehumidifying operation, and the lower the room humidity Hr to be obtained by the dehumidifying operation, the higher the dehumidifying level. Specifically, as the dehumidifying operation mode, the dehumidifying operation mode L having the lowest dehumidifying level, the moderate dehumidifying level dehumidifying operation mode M having the higher dehumidifying level than the dehumidifying operating mode L, and the dehumidifying operation mode M Three of the dehumidifying operation mode H, which has a high level, are prepared in the control unit 6. Here, the selection of the dehumidifying operation mode is selected by the room occupant from the remote control operation unit 64 of the remote control 60 in step ST11.

<Step ST12 (Dehumidifying Operation Mode L)>
When the dehumidifying operation mode L is selected in step ST11, the control unit 6 controls step ST12 (that is, steps ST21 to ST27).

-Step ST21 (Thermo-on)-
The control unit 6 performs the evaporation temperature Te of the refrigerant in the refrigerant circuit 10 at the target evaporation temperature at step ST21, that is, at the time of the operation of the dehumidifying operation (at the time of the operation of circulating the refrigerant by operating the compressor 21). Capacity control is performed to control the capacity of the compressor 21 so as to be Teds. Further, the control unit 6 performs air volume control for limiting the air volume of the indoor fan 32 to the air volume L or the air volume LL, unlike the step ST1 during the cooling operation, during the thermo-on of the step ST21.

  The displacement control of the compressor 21 is the same as step ST1 in the cooling operation except that the target evaporation temperature Tecs is set to the target evaporation temperature Teds. Therefore, the description of the control of the displacement of the compressor 21 is omitted here. Here, the target evaporation temperature Teds is set to a value equal to or less than the target evaporation temperature Tecs.

-Step ST22 (Determination 1 of Thermo OFF Condition)-
The control unit 6 determines whether or not the thermo-off condition is satisfied in step ST22 during the thermo-on in step ST21.

  The control unit 6 has a first thermo-off temperature condition based on the indoor temperature Tr and a thermo-off humidity condition based on the indoor humidity Hr as determination elements for determining whether the thermo-off condition is satisfied. Then, when both the first thermo-off temperature condition and the thermo-off humidity condition are satisfied, the control unit 6 determines that the thermo-off condition is satisfied, and one or both of the first thermo-off temperature condition and the thermo-off humidity condition are satisfied. If not, it is determined that the thermo-off condition is not satisfied. That is, in the dehumidifying operation mode L, unlike step ST2 at the time of the cooling operation, it is determined whether or not the thermo-off condition is satisfied in consideration of the thermo-off temperature condition as well as the thermo-off temperature condition.

  Specifically, during the thermo-on, the control unit 6 lowers the room temperature Tr and continues the state in which the room temperature Tr has reached the first thermo-off temperature TrdfL1 or less for a predetermined time tL. Is determined to satisfy the condition, and the first thermo-off is performed when the indoor temperature Tr is higher than the first thermo-off temperature TrdfL1 or when the state where the indoor temperature Tr reaches the first thermo-off temperature TrdfL1 does not continue for a predetermined time tL. It is determined that the temperature condition is not satisfied. Here, the first thermo-off temperature TrdfL1 is a value obtained by adding the first thermo-off temperature difference ΔTrdfL1 to the target indoor temperature Trs. The first thermo-off temperature difference ΔTrdfL1 is set to a value of about -1 degree to +1 degree, and the predetermined time tL is set to a value of about several tens of seconds to several minutes. Further, the first thermo-off temperature TrdfL1 (= target indoor temperature Trs + first thermo-off temperature difference ΔTrdfL1) may have the same value as the thermo-off temperature Trcf (= target indoor temperature Trs + thermo-off temperature difference ΔTrcf) during the cooling operation, It may be a low value.

  Further, the control unit 6 determines that the thermo-off humidity condition is satisfied when the indoor humidity Hr becomes low during the thermo-ON and the indoor humidity Hr reaches the target indoor humidity HrsL, and the indoor humidity Hr is greater than the target indoor humidity HrsL. If it is too high, it is determined that the thermo-off humidity condition is not satisfied. Here, when the dehumidifying operation mode L is selected in step ST11, the target indoor humidity HrsL is set to a value at which the dehumidifying level of about 60% to 70% is low (that is, a high relative humidity value).

  Here, whether or not the thermo-off condition is satisfied is determined based on whether or not the indoor temperature Tr has reached the first thermo-off temperature TrdfL1 and whether or not the indoor humidity Hr has reached the target indoor humidity HrsL. It is not limited to this. For example, whether the temperature difference ΔTr obtained by subtracting the target indoor temperature Trs from the indoor temperature Tr has reached the first thermo-off temperature difference ΔTrdfL1 and the humidity difference ΔHr obtained by subtracting the target indoor humidity Hrs from the indoor humidity Hr is 0 (zero). It may be judged by whether it reached. The determination based on the temperature difference ΔTr and the humidity difference ΔHr is also the same as determining whether the room temperature Tr has reached the first thermo-off temperature TrdfL1 and whether the room humidity Hr has reached the target room humidity HrsL. It is.

-Step ST23 (Thermo off)-
The control unit 6 is configured to satisfy the thermo-off condition by the indoor humidity Hr reaching the target indoor humidity HrsL when the indoor temperature Tr reaches the first thermo-off temperature TrdfL1 or less continuously for a predetermined time tL in step ST22. When it is determined in step ST23, the compressor 21 is stopped to stop the circulation of the refrigerant and to stop the operation of the dehumidifying operation (thermo-off). Further, the control unit 6 performs the thermo-off also when it is determined in step ST27 (described later) that the room temperature Tr reaches the second thermo-off temperature TrdfL2 or less and the thermo-off condition is satisfied.

-Step ST24 (Determination of Whether the Thermo-On Condition is Met)-
During the thermo-off of step ST23, the control unit 6 determines whether or not the thermo-on condition is satisfied in step ST24.

  The control unit 6 has a thermo-on temperature condition based on the indoor temperature Tr as a determination element for determining whether the thermo-on condition is satisfied, as in step ST4 during the cooling operation. Then, the control unit 6 determines that the thermo-on condition is satisfied when the thermo-on temperature condition is satisfied, and determines that the thermo-on condition is not satisfied when the thermo-on temperature condition is not satisfied. Specifically, the control unit 6 determines that the indoor temperature Tr satisfies the thermal on temperature condition when the indoor temperature Tr becomes higher than the thermal on temperature TrdnL during the thermal off, and the indoor temperature Tr is the thermal on temperature When the temperature is lower than TrdnL, it is determined that the thermo-on temperature condition is not satisfied. The thermo-on temperature TrdnL is a value obtained by adding the thermo-on temperature difference ΔTrdnL to the target indoor temperature Trs. The thermo-on temperature difference ΔTrdnL may be the same value as the thermo-on temperature Trcn during the cooling operation (= the target indoor temperature Trs + the thermo-on temperature difference ΔTrcn), or may be a low value.

  Here, whether or not the thermo-on condition is satisfied is determined based on whether or not the room temperature Tr has reached the thermo-on temperature TrdnL, but it is not limited to this. For example, it may be determined based on whether the temperature difference ΔTr obtained by subtracting the target indoor temperature Trs from the indoor temperature Tr has reached the thermo-on temperature difference ΔTrdnL, and the indoor temperature Tr has reached the thermo-on temperature TrdnL. It is the same as judging whether you

  Then, when it is determined that the thermo-on condition is satisfied in step ST24, the control unit 6 returns to step ST21, starts the compressor 21, and performs the dehumidifying operation (thermo-on).

-Step ST25 (Determination 2 of whether the thermo-off condition is satisfied)-
When the thermo-off condition (both the first thermo-off temperature condition and the thermo-off humidity condition) of step ST22 is not satisfied during the thermo-on of step ST21, the control unit 6 satisfies the first thermo-off temperature condition in step ST25. It is determined whether the humidity condition is not satisfied. That is, when the first thermo-off temperature condition is satisfied, the control unit 6 determines whether the thermo-off humidity condition is not satisfied. Then, when the first thermo-off temperature condition is satisfied and the thermo-off humidity condition is not satisfied, the control unit 6 performs the dehumidification continuation control of step ST26 without performing the thermo-off.

-Step ST26 (Thermo-on, continuous dehumidification control)-
In step ST26, the control unit 6 continues the capacity control for controlling the capacity of the compressor 21 and the air volume control of the indoor fan 32 so that the evaporation temperature Te of the refrigerant in the refrigerant circuit 10 becomes the target evaporation temperature Teds. However, here, unlike the capacity control and air flow control of step ST21, the controller 6 sets the capacity of the compressor 21 such that the evaporation temperature Te of the refrigerant in the indoor heat exchanger 31 falls below the dew point temperature Trw of the room air. And control the air volume of the indoor fan 32. Here, the air volume of the indoor fan 32 is controlled to the minimum air volume LL, and control is performed to reduce the capacity of the compressor 21 in the range where the evaporation temperature Te falls below the dew point temperature Trw.

  Here, the control unit 6 determines the target evaporation temperature Teds based on the dew point temperature Trw. Specifically, the control unit 6 calculates the dew point temperature Trw from the indoor temperature Tr and the indoor humidity Hr. Then, the control unit 6 subtracts the predetermined temperature difference ΔTrw from the calculated dew point temperature Trw to determine the target evaporation temperature Teds. That is, the control unit 6 determines the target evaporation temperature Teds to be lower than the dew point temperature Trw.

  Then, the room dehumidification is continued by such dehumidification continuation control, and when the room humidity Hr reaches the target room humidity HrsL, the control unit 6 performs both the first thermo-off temperature condition and the thermo-off humidity condition in step ST22. It is determined that the thermo-off condition is satisfied by satisfying the above, and the thermo-off is performed in step ST23.

-Step ST27 (Determination 3 of Whether the Thermo-off Condition is Satisfied)-
If the thermo-off condition (both the first thermo-off temperature condition and the thermo-off humidity condition) of step ST22 is not satisfied during the dehumidification continuation control of step ST26, the control unit 6 does not satisfy the thermo-off humidity condition in step ST27. It is determined whether the thermo-off condition is satisfied by satisfying the second thermo-off temperature condition.

  The control unit 6 further includes a second thermo-off temperature condition on the lower temperature side than the first thermo-off temperature condition as a determination element that determines whether the thermo-off condition is satisfied. Then, the control unit 6 determines that the thermo-off condition is satisfied when the second thermo-off temperature condition is satisfied even if the thermo-off humidity condition is not satisfied, and the thermo-off humidity condition and the second thermo-off temperature condition are not satisfied. It is determined that the thermo-off condition is not satisfied. That is, during the dehumidification continuation control of step ST26, in step ST22, not only it is determined whether both the first thermo-off temperature condition and the thermo-off humidity condition are satisfied, it is also determined whether the second thermo-off temperature condition is satisfied. ing.

  Specifically, the control unit 6 determines that the second thermo-off temperature condition is satisfied when the room temperature Tr is further lowered during the dehumidification continuation control and the room temperature Tr reaches the second thermo-off temperature TrdfL2 or less. When the room temperature Tr is higher than the second thermo-off temperature TrdfL2, it is determined that the second thermo-off temperature condition is not satisfied. Here, the second thermo-off temperature TrdfL2 is a value obtained by adding the second thermo-off temperature difference ΔTrdfL2 to the target indoor temperature Trs. Then, the second thermo-off temperature difference ΔTrdfL2 is set to a value (for example, a value of about -3 degrees to -2 degrees) lower than the first thermo-off temperature TrdfL1.

  Here, whether or not the thermo-off condition is satisfied is determined based on whether or not the room temperature Tr has reached the second thermo-off temperature TrdfL2. However, the present invention is not limited to this. For example, it may be determined based on whether the temperature difference ΔTr obtained by subtracting the target indoor temperature Trs from the indoor temperature Tr has reached the second thermo-off temperature difference ΔTrdfL2. The determination based on the temperature difference ΔTr is also the same as the determination based on whether the room temperature Tr has reached the second thermo-off temperature TrdfL2.

<Step ST13 (Dehumidifying Operation Mode M)>
When the dehumidifying operation mode M is selected in step ST11, the control unit 6 controls step ST13 (that is, steps ST31 to ST37).

  Here, the process of steps ST31 to ST37 of the dehumidifying operation mode M is the same as the process of steps ST21 to ST27 of the dehumidifying operation mode L. For this reason, here, the letter “L” in the description of steps ST21 to ST27 in the dehumidifying operation mode L is replaced with “M”, and steps ST21 to ST27 are replaced with ST31 to ST37 to explain steps ST31 to ST37. Omitted.

  However, with regard to the target indoor humidity HrsM, when the dehumidifying operation mode M is selected in step ST11, a value (for example, a moderate relative humidity of about 50% to 60%) lower than the target indoor humidity HrsL of the dehumidifying operating mode L Value).

  In the dehumidifying operation mode M, the first thermo-off temperature TrdfM1 (first thermo-off temperature difference ΔTrdfM1) may be set to the same value as the first thermo-off temperature TrdfL1 (first thermo-off temperature difference ΔTrdfL1) in the dehumidifying operation mode L. The first thermo-off temperature difference ΔTrdfM1 may have a low value (for example, a value of about −1.5 degrees to +0.5 degrees). The predetermined time tM may be the same value as the predetermined time tL in the dehumidifying operation mode L, but may be a long value. The thermo-on temperature TrdnM (= target indoor temperature Trs + thermo-on temperature difference Δ Trd nM) may be the same value as the thermo-on temperature Trdn L (= target indoor temperature Trs + thermo-on temperature difference Δ Trdn L) in the dehumidifying operation mode L, but may be a low value . The second thermo-off temperature TrdfM2 (= target indoor temperature Trs + second thermo-off temperature difference ΔTrdfM2) may be set to the same value as the second thermo-off temperature TrdfL2 (= target indoor temperature Trs + second thermo-off temperature difference ΔTrdfL2) in the dehumidifying operation mode L However, it may be a low value (for example, the second thermo-off temperature difference ΔTrdfM2 is a value of about -3.5 degrees to -2.5 degrees).

<Step ST14 (Dehumidifying Operation Mode H)>
When the dehumidifying operation mode H is selected in step ST11, the control unit 6 controls step ST14 (that is, steps ST41 to ST47).

  Here, the process of steps ST41 to ST47 of the dehumidifying operation mode H is the same as the process of steps ST21 to ST27 of the dehumidifying operation mode L. Therefore, in this case, the letter "L" in the description of steps ST21 to ST27 in the dehumidifying operation mode L is read as "H", and the steps ST21 to ST27 are read as ST41 to ST47, thereby explaining the steps ST41 to ST47. Omitted.

  However, as for the target indoor humidity HrsH, when the dehumidifying operation mode H is selected in step ST11, a value lower than the target indoor humidity HrsL, HrsM of the dehumidifying operating mode L, M (for example, about 40% to 50% lower) The relative humidity value of) is set.

  Further, in the dehumidifying operation mode H, the first thermo-off temperature TrdfH1 (first thermo-off temperature difference ΔTrdfH1) is the same as the first thermo-off temperature TrdfL1, TrdfM1 (first thermo-off temperature difference ΔTrdfL1, ΔTrdfM1) in the dehumidifying operation mode L, M. It may be a value, but may be a low value (for example, the first thermo-off temperature difference ΔTrdfH1 is a value of about −2 degrees to 0 degrees). The predetermined time tH may be the same value as the predetermined time tL, tM in the dehumidifying operation modes L, M, but may be a long value. The thermo-on temperature TrdnH (= target indoor temperature Trs + thermo-on temperature difference ΔTrdnH) may be the same value as the thermo-on temperature TrdnL, TrdnM (= target indoor temperature Trs + thermo-on temperature difference ΔTrdnL, ΔTrdnM) in the dehumidifying operation mode L, M. It may be a low value. The second thermo-off temperature TrdfH2 (= target indoor temperature Trs + second thermo-off temperature difference ΔTrdfH2), the second thermo-off temperature TrdfL2, TrdfM2 (= target indoor temperature Trs + second thermo-off temperature difference ΔTrdfL2, ΔTrdfM2) in the dehumidifying operation mode L, M The same value may be used, but a low value (for example, the second thermo-off temperature difference ΔTrdfH2 may have a value of about -4 degrees to -3 degrees).

(6) Characteristics Next, the characteristics of the air conditioner 1 will be described.

<A>
In the air conditioning apparatus 1 that performs the dehumidifying operation, even during the dehumidifying operation, the indoor temperature Tr approaches the target indoor temperature Trs and the indoor temperature Tr is the thermo-off temperature as in the cooling operation (processing of steps ST1 to ST4). If the thermo-off is performed when the temperature reaches the value, the room is not sufficiently dehumidified, and there is a possibility that the occupant feels uncomfortable due to insufficient dehumidification in the room. In particular, in a transient operation state where the target indoor temperature Trs is set high and the dehumidifying operation is started, the thermo-off is performed immediately after the start of the dehumidifying operation, and the dehumidifying deficiency in the room occurs. It tends to be easy. In addition, since the temperature in the indoor heat exchanger 31 rises during the thermo-off, the condensed water may be re-evaporated, and the indoor humidity Hr may be increased.

Therefore, here, as described above, when the control unit 6 does not satisfy the thermo-off humidity condition when the first thermo-off temperature condition (thermo-off temperature condition) is satisfied, the compressor 21 is not stopped. The capacity of the compressor 21 and the air volume of the indoor fan 32 are controlled such that the evaporation temperature Te of the refrigerant in the heat exchanger 31 is lower than the dew point temperature Trw of the indoor air (dehumidification continuation control, see steps ST26, ST36, ST46) ).

  Thereby, the room dehumidification can be continued in the state where condensation of indoor air occurs surely in the indoor heat exchanger 31. For this reason, when the thermo-off temperature condition is satisfied, the amount of dehumidification can be increased as compared to the case where the thermo-off is performed, and the possibility that the person in the room feels uncomfortable due to the lack of dehumidification in the room can be reduced.

  In particular, here, the control unit 6 controls the air volume of the indoor fan 32 to the minimum air volume LL and performs control to reduce the capacity of the compressor 21 in the range where the evaporation temperature Te falls below the dew point temperature Trw.

  Thus, the heat exchange between the refrigerant and the indoor air can be suppressed by reducing the flow rate of the refrigerant performing heat exchange in the indoor heat exchanger 31 and the air volume of the indoor air. For this reason, it is possible to suppress a decrease in the room temperature Tr, and to reduce the possibility that the room temperature Tr may be too low and the occupant may feel uncomfortable.

<B>
Here, as described above, the control unit 6 is configured to be able to select a plurality of dehumidifying operation modes having different dehumidifying levels as the dehumidifying operation (see steps ST11 to ST14).

  Thereby, the dehumidification driving | operation suitable for the needs of a person's room with a dehumidification level can be performed here.

<C>
Here, as described above, the control unit 6 changes the first thermo-off temperature condition (thermo-off temperature condition) to a lower temperature side as the dehumidifying level of the selected dehumidifying operation mode is higher (step ST22) See ST32, ST42, ST25, ST35, and ST45). Specifically, the thermo-off temperature difference is reduced in the order of the dehumidifying operation modes L, M and H (that is, ΔTrdfL1>ΔTrdfM1> ΔTrdfH1), whereby the thermo-off temperatures in the dehumidifying operating mode L, M and H are in order. To a low value (ie, TrdfL1>TrdfM1> TrdfH1).

  As a result, the higher the dehumidification level is, the harder it is to meet the thermo-off temperature condition, and the amount of dehumidification can be increased until the thermo-off temperature condition is satisfied.

  Here, the control unit 6 may change the thermo-off temperature condition during the dehumidifying operation to a temperature lower than the thermo-off temperature condition during the cooling operation. Specifically, the thermo-off temperature differences ΔTrdfL1, ΔTrdfM1, and ΔTrdfH1 during the dehumidifying operation are set to values lower than the thermo-off temperature difference ΔTrcf during the cooling operation. Thereby, the room can be dehumidified more than in the cooling operation.

<D>
However, there is a possibility that room temperature Tr may become too low by continuation of dehumidification after satisfying the above 1st thermo-off temperature conditions (thermo-off temperature conditions). For example, it is a case where thermo-off humidity conditions are not satisfied also by continuation of dehumidification after meeting thermo-off temperature conditions. In such a case, the room temperature Tr may be too low and the occupant may feel uncomfortable.

  Therefore, here, as described above, as a determination element for determining whether or not the thermo-off condition is satisfied, the control unit 6 further sets the second thermo-off temperature condition on the lower temperature side than the first thermo-off temperature condition (thermo-off temperature condition). Have. Then, even if the thermo-off humidity condition is not satisfied, the control unit 6 determines that the thermo-off condition is satisfied if the second thermo-off temperature condition on the low temperature side is satisfied (see steps ST27, ST37, and ST47). .

  Thereby, by continuing the dehumidification after satisfying the first thermo-off temperature condition, thermo-off can be performed before the indoor temperature Tr becomes too low (see steps ST23, ST33, and ST43). For this reason, the amount of dehumidification is increased by continuing dehumidification after satisfying the first thermo-off temperature condition, thereby reducing the possibility that the occupant feels uncomfortable due to insufficient dehumidification in the room and satisfying the first thermo-off temperature condition. Excessive continuation of dehumidification afterward can be suppressed, and the possibility that the occupant feels uncomfortable can be reduced because the room temperature Tr becomes too low.

<E>
Here, as described above, when the control unit 6 reaches the second thermo-off temperatures TrdfL2, TrdfM2, TrdfH2 whose room temperature Tr is lower than the first thermo-off temperatures TrdfL1, TrdfM1, TrdfH1, the second thermo-off temperature It is determined that the condition is satisfied (see steps ST27, ST37 and ST47).

  As a result, here, the thermo-off is performed when the room temperature Tr reaches the second thermo-off temperatures TrdfL2, TrdfM2, TrdfH2, so that the possibility of the room temperature Tr becoming too low can be reduced.

<F>
Here, as described above, as the dehumidifying level of the selected dehumidifying operation mode is higher, the control unit 6 changes the second thermo-off temperature condition to a lower temperature side (see steps ST27, ST37, and ST47). . Specifically, the second thermo-off temperature difference is reduced in the order of the dehumidifying operation modes L, M and H (that is, ΔTrdfL2>ΔTrdfM2> ΔTrdfH2), whereby the dehumidifying operating modes L, M and H are in the order of The second thermo-off temperature is set to a low value (ie, TrdfL2>TrdfM2> TrdfH2).

  Thereby, since it becomes difficult to satisfy | fill 2nd thermo-off temperature conditions here so that a dehumidification level becomes high, the dehumidification amount until it satisfy | fills 2nd thermo-off temperature conditions can be increased.

<G>
Here, as described above, when the control unit 6 continues the state in which the room temperature Tr has reached the first thermo-off temperatures TrdfL1, TrdfM1, TrdfH1 for a predetermined time tL, tM, tH, the first It is determined that the thermo-off temperature condition is satisfied (see steps ST22, ST32, ST42, ST25, ST35, and ST45).

  Here, as compared with the case where it is determined that the first thermo-off temperature condition is satisfied when the room temperature Tr reaches the first thermo-off temperature TrdfL1, TrdfM1, TrdfH1, the time until the first thermo-off temperature condition is satisfied, The amount of dehumidification can be increased. In addition, it is possible to prevent an erroneous determination as to whether or not the first thermo-off temperature condition is satisfied.

  Here, as the dehumidification level of the selected dehumidification operation mode is higher, the control unit 6 may lengthen the predetermined time (see steps ST22, ST32, ST42, ST25, ST35, and ST45). Specifically, the predetermined time is set to a long value in the order of the dehumidifying operation modes L, M and H (set tL <tM <tH).

  Thereby, since it becomes difficult to satisfy | fill 1st thermo-off temperature conditions here so that a dehumidification level becomes high, the dehumidification amount until it satisfy | fills 1st thermo-off temperature conditions can be increased.

(7) Modifications <A>
In the above embodiment, in the dehumidifying continuation control in steps ST26, ST36, and ST46, the control unit 6 performs control to reduce the capacity of the compressor 21 in the range where the evaporation temperature Te falls below the dew point temperature Trw. Specifically, the control unit 6 determines the target evaporation temperature Teds by subtracting the predetermined temperature difference ΔTrw from the dew point temperature Trw, and the capacity of the compressor 21 is set such that the evaporation temperature Te becomes the target evaporation temperature Teds. I have control.

  However, when the target evaporation temperature Teds is set to a lower value in the capacity control of the compressor 21, the capacity of the compressor 21 is controlled to be larger, and not only dehumidification of the room is promoted, but also the room The temperature Tr also tends to decrease.

  Therefore, in this case, in the dehumidification continuation control of steps ST26, ST36, and ST46, control is performed to reduce the capacity of the compressor 21 until it is determined that the room temperature Tr is rising.

  Specifically, as shown in FIG. 8, the control unit 6 changes the predetermined temperature difference ΔTrw to be smaller in step ST52 until it is determined in step ST51 that the room temperature Tr is rising. Thus, the capacity control of the compressor 21 is performed such that the target evaporation temperature Teds becomes higher in the range below the dew point temperature Trw.

  Hereby, the flow rate of the refrigerant performing heat exchange in the indoor heat exchanger 31 can be reduced to the flow rate at which dehumidification can be performed without lowering the room temperature Tr, and the occupant may feel uncomfortable. It can be further reduced. Also, the frequency of thermo-off can be reduced.

<B>
In the above embodiment and modification A, in the dehumidifying continuation control in steps ST26, ST36, and ST46, the control unit 6 performs control to reduce the capacity of the compressor 21 in the range where the evaporation temperature Te falls below the dew point temperature Trw. ing. Specifically, the control unit 6 determines the target evaporation temperature Teds by subtracting the predetermined temperature difference ΔTrw from the dew point temperature Trw, and the capacity of the compressor 21 is set such that the evaporation temperature Te becomes the target evaporation temperature Teds. I have control.

  However, if the target evaporation temperature Teds is set to be low, indoor air may be excessively cooled in the indoor heat exchanger 31, and in the vicinity of the outlet 46 of the indoor unit 3 that houses the indoor heat exchanger 31, Condensation may occur.

  Therefore, here, in the dehumidification continuation control in steps ST26, ST36, ST46, the control unit 6 performs control to reduce the capacity of the compressor 21 within a range equal to or higher than the lower limit value Tem of the evaporation temperature Te.

  Specifically, as shown in FIG. 9, the control unit 6 first determines the lower limit value Tem from the room temperature Tr and the room humidity Hr in step ST53. Here, the lower limit value Tem is determined in view of whether condensation does not occur in the vicinity of the outlet 46 of the indoor unit 3 regardless of how low the evaporation temperature Te is viewed from the indoor temperature Tr and the indoor humidity Hr. Ru. For this reason, when the room temperature Tr is low or the room humidity Hr is low, dew condensation hardly occurs, so the lower limit Tem is determined to be low, and the room temperature Tr is high, Further, when the indoor humidity Hr is high, dew condensation is likely to occur, so the lower limit value Tem is determined to be high. Next, in step ST54, the control unit 6 determines whether the target evaporation temperature Teds is equal to or higher than the lower limit value Tem. Then, when it is determined in step ST54 that the target evaporation temperature Teds is not the lower limit value Tem or more, the control unit 6 performs the change to reduce the predetermined temperature difference ΔTrw in step ST55, whereby the target evaporation temperature Teds is smaller. The displacement control of the compressor 21 is performed so as to increase in a range below the dew point temperature Trw.

  Thus, here, by performing control to reduce the capacity of the compressor 21 within the range of the lower limit value Tem or more of the evaporation temperature Te, the indoor heat is excessively cooled in the indoor heat exchanger 31, so that the room In the vicinity of the outlet 46 of the unit 3, the risk of dew condensation can be reduced.

  Further, when the dehumidifying operation is performed, the dehumidification in the room advances and the indoor humidity Hr gradually decreases, so that the possibility of dew condensation in the vicinity of the outlet 46 of the indoor unit 3 tends to be gradually reduced. Here, since the control unit 6 determines the lower limit value Tem from the room temperature Tr and the room humidity Hr in step ST53, the lower limit value Tem becomes low during the dehumidification continuation control. That is, here, the control unit 6 lowers the lower limit value Tem of the evaporation temperature Te during the dehumidifying operation.

  Thereby, the range which lowers evaporation temperature Te can be expanded here, and evaporation temperature Te can be made to certainly fall below dew point temperature Trw. In particular, here, the range in which the evaporation temperature Te is reduced can be expanded in consideration of the indoor temperature Tr and the indoor humidity Hr, so that the occurrence of condensation can be suppressed as much as possible.

<C>
In the above embodiment and Modifications A and B, three of the dehumidifying operation modes L, M and H can be selected as a plurality of dehumidifying operation modes having different dehumidifying levels, but the present invention is not limited thereto. Alternatively, two dehumidification operating modes may be used, or four or more dehumidifying operating modes may be used.

<D>
In the said embodiment and modification AC, although the example which employ | adopted the ceiling embedded type was demonstrated as the indoor unit 3 which accommodates the indoor heat exchanger 31, it is not limited to this, It may be another type of indoor unit such as a wall-mounted type.

  While the embodiments of the present disclosure have been described above, it will be understood that various changes in form and detail can be made without departing from the spirit and scope of the present disclosure as set forth in the claims. .

  The present disclosure is widely applicable to an air conditioner performing a dehumidifying operation.

DESCRIPTION OF SYMBOLS 1 Air conditioning apparatus 6 Control part 10 Refrigerant circuit 21 Compressor 24 Outdoor heat exchanger 25 Expansion valve (expansion mechanism)
31 indoor heat exchanger 32 indoor fan

JP 2004-76973 A

Claims (8)

A refrigerant circuit (10) configured by connecting a compressor (21), an outdoor heat exchanger (24), an expansion mechanism (25), and an indoor heat exchanger (31);
An indoor fan (32) for sending indoor air to the indoor heat exchanger;
A control unit (6) for performing a dehumidifying operation in which the refrigerant sealed in the refrigerant circuit is circulated in the order of the compressor, the outdoor heat exchanger, the expansion mechanism, and the indoor heat exchanger;
Equipped with
When the indoor temperature satisfies the thermo-off temperature condition during the dehumidifying operation, the control unit does not perform the thermo-off to stop the compressor, and the evaporation temperature of the refrigerant in the indoor heat exchanger is the indoor air Controlling the capacity of the compressor and the air volume of the indoor fan so as to be lower than the dew point temperature;
Air conditioner (1). The control unit controls the air volume of the indoor fan to a minimum air volume, and performs control to reduce the capacity of the compressor within a range where the evaporation temperature falls below the dew point temperature.
The air conditioner according to claim 1. The control unit performs control to reduce the capacity of the compressor until the indoor temperature rises.
The air conditioner according to claim 2. The control unit performs control to reduce the capacity of the compressor within a range not less than the lower limit value of the evaporation temperature.
An air conditioner according to claim 2 or 3. The control unit lowers the lower limit value of the evaporation temperature during the dehumidifying operation.
The air conditioner according to claim 4. The control unit determines the lower limit value of the evaporation temperature from the room temperature and the room humidity.
The air conditioner according to claim 5. The control unit is configured to be able to select a plurality of dehumidifying operation modes having different dehumidifying levels as the dehumidifying operation.
The air conditioning apparatus according to any one of claims 1 to 6. The control unit changes the thermo-off temperature condition to a lower temperature side as the dehumidifying level of the selected dehumidifying operation mode is higher.
The air conditioner according to claim 7.

Images