JP7648889B2 - Air conditioner indoor unit - Google Patents

Description

Related to indoor units of air conditioners.

Patent document 1 (JP 2011-99613 A) discloses an indoor unit of an air conditioner equipped with multiple air direction adjustment plates provided at each of multiple air outlets. In the indoor unit of Patent document 1, the rotation state of the four air direction adjustment plates is individually and independently adjusted for the four long side air outlets based on a command from the user to change their position, thereby performing individual air volume suppression control to minimize the volume of air blown out from a specific long side air outlet.

However, the air conditioner of Patent Document 1 may give the occupants a feeling of cold air during heating operation, and may give the occupants a feeling of warm air during cooling or dehumidification operation.

The inventors realized that the above-mentioned draft feeling is felt by occupants when the indoor temperature approaches the set temperature and the air conditioning load is low during operation of the air conditioner, and thus completed the technology disclosed herein.

The indoor unit of an air conditioner according to a first aspect is an indoor unit of an air conditioner that performs air conditioning operation, and includes a heat exchanger, a casing, multiple opening/closing members, and a control unit. The heat exchanger exchanges heat between indoor air and a refrigerant to generate conditioned air. The casing is formed with multiple air outlets for blowing out the conditioned air. The multiple opening/closing members open and close the multiple air outlets. The control unit controls the attitude of the opening/closing members. The control unit controls the attitude of the opening/closing members to close at least one of the multiple air outlets during low-load operation where the load of the air conditioning operation is equal to or lower than a predetermined value.

According to the indoor unit of the air conditioner of the first aspect, the position of the opening and closing member is controlled so as to close at least one of the air outlets during low-load operation where the load of the air conditioner is equal to or lower than a predetermined value. This makes it possible to reduce the amount of heat exchanged between the refrigerant and the indoor air in the heat exchanger during low-load operation. This makes it possible to prevent the temperature of the conditioned air blown out from the air outlet from decreasing during heating operation, and to prevent the temperature of the conditioned air blown out from the air outlet from increasing during cooling operation or dehumidification operation. This makes it possible to prevent the occupants from feeling cold air during heating operation of the air conditioner, and to prevent the occupants from feeling warm air during cooling operation or dehumidification operation. This makes it possible to suppress the feeling of a draft.

The indoor unit of the air conditioner according to the second aspect is the indoor unit of the air conditioner according to the first aspect, and the control unit controls the position of the opening and closing member to close at least one of the multiple air outlets when the condensation temperature of the refrigerant in the heat exchanger drops to a first threshold during heating operation.

When the condensation temperature of the refrigerant drops during heating operation, the temperature of the conditioned air that has exchanged heat with the refrigerant in the heat exchanger drops. For this reason, in the indoor unit of the air conditioner according to the second aspect, the first threshold is set to a lower limit value that does not give the feeling of cold air during heating operation, and when the condensation temperature drops to the first threshold, the opening and closing member is controlled to close at least one of the air outlets. This makes it possible to prevent the conditioned air blown out of the air outlet from dropping to a temperature that gives the feeling of cold air during heating operation.

The indoor unit of the air conditioner according to the third aspect is the indoor unit of the air conditioner according to the second aspect, and the control unit controls the position of the opening and closing member to close at least one of the multiple air outlets when the condensation temperature of the refrigerant in the heat exchanger drops to a first threshold value during heating operation and the temperature of the indoor air continues to rise.

In the indoor unit of the air conditioner according to the third aspect, in addition to the second aspect, when the temperature of the indoor air rises during heating operation, the heating load becomes lower, and the temperature of the conditioned air that has been heat exchanged in the heat exchanger is likely to fall. Therefore, when the condensation temperature falls during heating operation and the temperature of the indoor air rises, the control unit closes at least one of the air outlets with the opening and closing member, which is highly effective in suppressing the feeling of cold air.

The indoor unit of the air conditioner according to the fourth aspect is the indoor unit of the air conditioner according to the first aspect, and the control unit controls the position of the opening and closing member to close at least one of the multiple air outlets when the evaporation temperature of the refrigerant in the heat exchanger rises to a second threshold during cooling operation or dehumidification operation.

When the evaporation temperature of the refrigerant drops during cooling or dehumidification operation, the temperature of the conditioned air that has been heat exchanged in the heat exchanger rises. For this reason, in the indoor unit of the air conditioner according to the fourth aspect, the second threshold is set to an upper limit value that does not give the feeling of warm air during cooling or dehumidification operation, and the position of the opening and closing member is controlled so that at least one of the air outlets is closed when the evaporation temperature rises to the second threshold. This makes it possible to prevent the conditioned air blown out of the air outlets from rising to a temperature that gives the feeling of warm air during cooling or dehumidification operation.

The indoor unit of the air conditioner according to the fifth aspect is the indoor unit of the air conditioner according to the fourth aspect, and controls the position of the opening and closing member to close at least one of the multiple air outlets when the evaporation temperature of the refrigerant in the heat exchanger rises to a second threshold value during cooling operation or dehumidification operation and the indoor air temperature continues to decrease.

In the indoor unit of the air conditioner according to the fifth aspect, in addition to the fourth aspect, when the temperature or humidity of the indoor air drops during cooling or dehumidification operation, the cooling load or dehumidification load becomes lower, so the temperature of the conditioned air that has been heat exchanged in the heat exchanger is likely to rise. Therefore, when the evaporation temperature rises and the temperature of the indoor air drops during cooling or dehumidification operation, the control unit is highly effective in closing at least one of the air outlets with the opening and closing member.

The indoor unit of the air conditioning device according to the sixth aspect is the indoor unit of the air conditioning device according to the fourth or fifth aspect, and the second threshold value is the dew point temperature of the indoor air.

When the evaporation temperature of the refrigerant rises to the dew point temperature of the indoor air during cooling operation, the indoor air is no longer cooled to the refrigerant in the heat exchanger. For this reason, in the indoor unit of the air conditioner according to the sixth aspect, the dew point temperature is set as the second threshold so that the indoor air is cooled to the refrigerant in the heat exchanger. This makes it possible to perform cooling or dehumidifying operation during low-load operation while maintaining the refrigerant at or below the dew point temperature. Therefore, it is possible to realize an indoor unit that prevents the occupants from feeling warm air during cooling or dehumidifying operation.

The indoor unit of the air conditioner according to the seventh aspect is the indoor unit of the air conditioner according to the first aspect to the sixth aspect, and the casing has three or more air outlets. The control unit controls the attitude of the multiple opening and closing members so that after at least one of the multiple air outlets is closed by the opening and closing member, at least one of the other air outlets is closed by the opening and closing member.

In the indoor unit of the air conditioner according to the seventh aspect, after at least one air outlet is closed by the opening/closing member, if suppression of the draft feeling is insufficient, another air outlet can be controlled to be closed by the opening/closing member.

The indoor unit of the air conditioner according to the eighth aspect is an indoor unit of the air conditioner according to the first aspect to the seventh aspect, and the control unit controls the opening and closing member to close at least one of the air outlets located in a direction facing in the direction where no people are present.

In the indoor unit of the air conditioner according to the eighth aspect, after at least one of the air outlets is closed, conditioned air with a reduced draft feeling can be blown out. Therefore, comfort can be improved by supplying conditioned air with a reduced draft feeling in the direction where people are present.

The indoor unit of the air conditioner according to the ninth aspect is the indoor unit of the air conditioner according to the first aspect to the eighth aspect, and one opening and closing member opens and closes one air outlet.

In the indoor unit of the air conditioner according to the ninth aspect, one opening/closing member is provided for one air outlet, so that it is easy to control the closing of the air outlet with the opening/closing member.

1 is a schematic configuration diagram of an air conditioning apparatus according to an embodiment of the present disclosure. FIG. 2 is an external perspective view of an indoor unit constituting the air conditioning apparatus. FIG. 3 is a schematic side cross-sectional view of the indoor unit, taken along line I-O-I in FIG. 2. FIG. 2 is a control block diagram of the air conditioning apparatus. FIG. 4 is a diagram for explaining control of a heating operation according to an embodiment of the present disclosure. FIG. 4 is a diagram for explaining control of a cooling operation and a dehumidification operation according to an embodiment of the present disclosure. 4 is a flowchart illustrating a method for controlling an opening/closing member according to an embodiment of the present disclosure.

(1) Equipment configuration of an air conditioner As shown in Fig. 1, an air conditioner 1 employing an indoor unit 3 according to an embodiment of the present disclosure is a device that conditions the air inside a building or the like by a vapor compression refrigeration cycle. The air conditioner 1 mainly has an outdoor unit 2, an indoor unit 3, and a liquid refrigerant connection pipe 4 and a gas refrigerant connection pipe 5 that connect the outdoor unit 2 and the indoor unit 3. A vapor compression 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 connection pipe 4 and the gas refrigerant connection pipe 5.

(1-1) Outdoor Unit The outdoor unit 2 is installed outdoors (on the roof of a building, near the exterior wall of a building, etc.). As described above, the outdoor unit 2 is connected to the indoor unit 3 via the liquid refrigerant connection pipe 4 and the gas refrigerant connection pipe 5, and constitutes a part of the refrigerant circuit 10. The outdoor unit 2 mainly has 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 the low-pressure refrigerant in the refrigeration cycle until it becomes high pressure. Here, a compressor with a sealed structure is used as the compressor 21, in which a volumetric compression element (not shown), such as a rotary or scroll type, is rotated and driven by a compressor motor 22. In addition, the rotation speed (frequency) of the compressor motor 22 can be controlled by an inverter or the like, and the capacity of the compressor 21 can be controlled.

The four-way switching valve 23 is a valve for switching the direction of refrigerant flow when switching between cooling or dehumidification operation and heating operation. During cooling or dehumidification operation, the four-way switching valve 23 connects the discharge side of the compressor 21 to the gas side of the outdoor heat exchanger 24, and connects the gas side of the indoor heat exchanger 31 (described later) to the suction side of the compressor 21 via the gas refrigerant connection pipe 5 (see the solid line of the four-way switching valve 23 in FIG. 1). During heating operation, the four-way switching valve 23 connects the discharge side of the compressor 21 to the gas side of the indoor heat exchanger 31 via the gas refrigerant connection pipe 5, and connects the gas side of the outdoor heat exchanger 24 to the suction side of the compressor 21 (see the dashed line of the four-way switching valve 23 in FIG. 1).

The outdoor heat exchanger 24 is a heat exchanger that functions as a refrigerant radiator during cooling or dehumidification operation, and as a refrigerant evaporator during 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 is an expansion mechanism that can reduce the pressure of the high-pressure liquid refrigerant that has dissipated heat in the outdoor heat exchanger 24 before being sent to the indoor heat exchanger 31 during cooling or dehumidification operation, and can reduce the pressure of the high-pressure liquid refrigerant that has dissipated heat in the indoor heat exchanger 31 before being sent to the outdoor heat exchanger 24 during heating operation. Here, an electric expansion valve with an opening controllable is used as the expansion valve 25.

The outdoor unit 2 is also provided with an outdoor fan 26 that draws in outdoor air into the outdoor unit 2, supplies the outdoor air to the outdoor heat exchanger 24, and then exhausts the air outside the outdoor unit 2. Therefore, the outdoor heat exchanger 24 uses the outdoor air as a cooling or heating source to dissipate heat or evaporate the refrigerant. The outdoor fan 26 is driven to rotate by an 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 28a that detects the suction pressure of the compressor 21, a suction temperature sensor 28b that detects the suction temperature of the compressor 21, a discharge pressure sensor 29a that detects the discharge pressure of the compressor 21, and a discharge temperature sensor 29b that detects the discharge temperature of the compressor 21.

(1-2) Refrigerant communication pipe The refrigerant communication pipes 4, 5 are refrigerant pipes that are installed on-site when the air conditioning apparatus 1 is installed at the installation location of a building or the like. One end of the liquid refrigerant communication pipe 4 is connected to the expansion valve 25 side of the outdoor 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 outdoor 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.

(1-3) Indoor Unit The indoor unit 3 is installed indoors (inside the building). As described above, the indoor unit 3 is connected to the outdoor unit 2 via the liquid refrigerant connection pipe 4 and the gas refrigerant connection pipe 5, and constitutes a part of the refrigerant circuit 10. As shown in Figures 1 to 3, the indoor unit 3 mainly has a casing 41, an opening and closing member 49, an indoor heat exchanger 31, and an indoor fan 32. Here, a type of indoor unit called a ceiling embedded type is used as the indoor unit 3.

As shown in Figures 2 and 3, the casing 41 houses the components inside. The casing 41 is composed of a casing body 41a and a decorative panel 42 arranged below the casing body 41a. As shown in Figure 2, the casing body 41a is inserted into an opening formed in the ceiling U. The decorative panel 42 is arranged to be fitted into the opening in the ceiling U.

2 and 3, the casing body 41a is a box-shaped body with a generally octagonal shape in plan view, with long and short sides alternately formed, and its bottom surface is open. The casing body 41a has a generally octagonal top plate 43 with long and short sides alternately formed in succession, and a side plate 44 extending downward from the periphery of the top plate 43.

The decorative panel 42 forms the underside of the casing 41, is a plate-like body that is approximately polygonal (here, approximately rectangular) in plan view, and is mainly composed of a panel body 42a fixed to the lower end of the casing body 41a. The panel body 42a has, approximately in the center, an intake port 45 that draws in indoor air, and an outlet port 46 that blows conditioned air into the room.

The intake port 45 is a substantially rectangular opening. The intake port 45 is provided with an intake grille 47 and an intake filter 48 for removing dust from the air drawn in through the intake port 45.

The air outlet 46 is formed to surround the suction port 45 in a plan view. The air outlet 46 has multiple (four in this case) side air outlets 46a formed along each side of the rectangular panel body 42a, and multiple (four in this case) corner air outlets 46b formed at the corners of the panel body 42a.

The multiple opening/closing members 49 open and close the multiple air outlets 46. When the opening/closing members 49 open the air outlets 46, conditioned air is blown out from the air outlets 46. When the opening/closing members 49 close the air outlets 46, conditioned air is not blown out from the air outlets 46. The opening/closing members 49 can close the entire air outlets 46, close a portion of the air outlets 46, or open the entire air outlets 46. The opening/closing members 49 can also change the direction of the conditioned air blown out from the air outlets 46 into the room.

In this embodiment, an opening/closing member 49 is provided at each of the multiple air outlets 46a. In other words, one opening/closing member 49 opens and closes one air outlet 46a. Here, four opening/closing members 49 are provided at the four side air outlets 46a. On the other hand, no opening/closing member 49 is provided at the corner air outlet 46b.

The opening/closing member 49 is a plate-like member that extends in an elongated manner along the longitudinal direction of the side air outlet 46a. The opening/closing member 49 is configured to be rotated around the longitudinal axis to open and close the air outlet 46. The opening/closing member 49 is also configured to be rotated around the longitudinal axis to change the wind direction angle in the vertical direction.

Inside the casing body 41a, the indoor heat exchanger 31 and the indoor fan 32 are mainly arranged.

The indoor heat exchanger 31 exchanges heat between the indoor air and the refrigerant to generate conditioned air. The indoor heat exchanger 31 is a heat exchanger that functions as a refrigerant evaporator during cooling or dehumidifying operation and as a refrigerant radiator during heating operation. The liquid side of the indoor heat exchanger 31 is connected to the liquid refrigerant connection pipe 4, and the gas side is connected to the gas refrigerant connection pipe 5.

The indoor heat exchanger 31 is a heat exchanger that is bent and positioned so as to surround the indoor fan 32 in a plan view. The indoor heat exchanger 31 exchanges heat between the indoor air drawn into the casing body 41a by the indoor fan 32 and the refrigerant. In addition, a drain pan 31a is positioned below the indoor heat exchanger 31 to receive drain water generated when moisture in the indoor air is condensed by the indoor heat exchanger 31. The drain pan 31a is attached to the bottom of the casing body 41a.

The indoor fan 32 is a fan that draws indoor air into the casing body 41a through the intake port 45 of the decorative panel 42 and blows it out from the casing body 41a into the room through the exhaust port 46 of the decorative panel 42. For this reason, the indoor heat exchanger 31 uses the indoor air as a cooling or heating source to dissipate heat and evaporate the refrigerant. Here, a centrifugal fan that draws in indoor air from below and blows it out toward the outer periphery in a plan view is used as the indoor fan 32. The indoor fan 32 is driven to rotate by an indoor fan motor 33 provided in the center of the top plate 43 of the casing body 41a. In addition, here, the indoor fan motor 33 can be controlled in rotation speed (frequency) by an inverter or the like, thereby controlling the air volume of the indoor fan 32.

Specifically, the indoor fan 32 has four airflow rates: maximum airflow rate H, medium airflow rate M which is smaller than airflow rate H, small airflow rate L which is smaller than airflow rate M, and minimum airflow rate LL which is smaller than airflow rate L. Here, airflow rate LL is an airflow rate that cannot be set by the resident using the remote control 60 (described below).

The indoor unit 3 is also provided with various sensors. Specifically, the indoor unit 3 is provided with an indoor temperature sensor 34 and an indoor humidity sensor 35 that detect the temperature (indoor temperature Tr) and humidity (indoor humidity Hr) of the indoor air drawn into the indoor unit 3. Here, the indoor temperature sensor 34 and the indoor humidity sensor 35 are positioned near the intake port 45.

The indoor unit 3 is also provided with a human detection sensor 36 that detects the location of a person in the room. Here, an infrared sensor having one or more infrared receiving elements is used as the human detection sensor 36, and is provided at a corner of the decorative panel 42. Note that the human detection sensor 36 does not have to be provided at the corner of the decorative panel 42, and may be provided in another part of the indoor unit 3, or may be provided somewhere in the room other than the indoor unit 3.

(2) Control configuration of the air conditioner As shown in Fig. 4, the air conditioner 1 has a control device 6 in which an outdoor control unit 20, an indoor control unit 30, and a remote control 60 are connected via transmission lines and communication lines in order to control the operation of the constituent devices. The outdoor control unit 20 is provided in the outdoor unit 2. The indoor control unit 30 is provided in the indoor unit 3. The remote control 60 is provided indoors. Note that here, the outdoor control unit 20, the indoor control unit 30, and the remote control 60 are wired-connected via transmission lines and communication lines, but they may also be connected wirelessly.

The outdoor control unit 20, indoor control unit 30, and control unit of the remote control 60 of the air conditioning device 1 perform various calculations and processing, and are realized, for example, by a calculation processing device such as a CPU.

(2-1) Outdoor control unit As described above, the outdoor control unit 20 is provided in the outdoor unit 2 and mainly has an outdoor CPU 20a, an outdoor transmission unit 20b, and an outdoor memory unit 20c. The outdoor control unit 20 is configured to be able to receive detection signals from the suction pressure sensor 28a, the suction temperature sensor 28b, the discharge pressure sensor 29a, and the discharge temperature sensor 29b.

The outdoor CPU 20a is connected to the outdoor transmission unit 20b and the outdoor memory unit 20c. The outdoor transmission unit 20b transmits control data and the like between the indoor control unit 30 and the outdoor memory unit 20c. The outdoor memory unit 20c stores the control data and the like. The outdoor CPU 20a transmits and reads and writes the control data and the like via the outdoor transmission unit 20b and the outdoor memory unit 20c, while controlling the operation of the compressor 21, four-way switching valve 23, expansion valve 25, outdoor fan 26, and other components provided in the outdoor unit 2.

(2-2) Indoor control unit As described above, the indoor control unit 30 is provided in the indoor unit 3, and mainly has an indoor CPU 30a, an indoor transmission unit 30b, an indoor storage unit 30c, and an indoor communication unit 30d. The indoor control unit 30 is configured to be able to receive detection signals from the indoor temperature sensor 34, the indoor humidity sensor 35, and the human detection sensor 36.

The indoor CPU 30a is connected to the indoor transmission unit 30b, the indoor memory unit 30c, and the indoor communication unit 30d. The indoor transmission unit 30b transmits control data and the like to the outdoor control unit 20. The indoor memory unit 30c stores control data and the like. The indoor communication unit 30d transmits and receives control data and the like to and from the remote control 60. The indoor CPU 30a transmits, reads, writes, and transmits and receives control data and the like via the indoor transmission unit 30b, the indoor memory unit 30c, and the indoor communication unit 30d, while controlling the operation of the indoor fan 32, the opening and closing member 49, and the like, which are components provided in the indoor unit 3.

(2-3) Remote Control As described above, the remote control 60 is provided indoors, and mainly includes a remote control CPU 61 , a remote control storage unit 62 , a remote control communication unit 63 , a remote control operation unit 64 , and a remote control display unit 65 .

The remote control CPU 61 is connected to a remote control storage unit 62, a remote control communication unit 63, a remote control operation unit 64, and a remote control display unit 65. The remote control storage unit 62 stores control data, etc. The remote control communication unit 63 transmits and receives control data, etc. with the indoor communication unit 30d. The remote control operation unit 64 accepts input of control commands, etc. from the occupant. The remote control display unit 65 displays operation, etc. The remote control CPU 61 accepts input of operation commands, control commands, etc. via the remote control operation unit 64, reads and writes control data, etc. to the remote control storage unit 62, and displays the operation status and control status on the remote control display unit 65, while issuing control commands, etc. to the indoor control unit 30 via the remote control communication unit 63.

Thus, the air conditioning device 1 has a control device 6 that controls the operation of the constituent devices. The control device 6 controls the constituent devices such as the compressor 21, four-way switching valve 23, expansion valve 25, outdoor fan 26, indoor fan 32, and opening/closing member 49 based on detection signals from the suction pressure sensor 28a, suction temperature sensor 28b, discharge pressure sensor 29a, discharge temperature sensor 29b, indoor temperature sensor 34, indoor humidity sensor 35, and human detection sensor 36, and is configured to perform air conditioning operations such as cooling operation, dehumidification operation, and heating operation, as well as various controls.

(3) Operation Next, a description will be given of the operation of the air conditioner 1. The air conditioner 1 of this embodiment performs heating operation, cooling operation, and dehumidification operation as air conditioning operations.

(3-1) Heating operation The heating operation is performed by the control device 6, which receives a heating operation command via the remote control operation unit 64, controlling the operation of the compressor 21, four-way switching valve 23, expansion valve 25, outdoor fan 26, indoor fan 32, opening/closing member 49, etc., which are components of the outdoor unit 2 and the indoor unit 3.

During heating operation, the four-way switching valve 23 is switched so that the outdoor heat exchanger 24 functions as a refrigerant evaporator and the indoor heat exchanger 31 functions as a refrigerant radiator (the state shown by the dashed line of the four-way switching valve 23 in Figure 1).

In the refrigerant circuit 10 in this state, the low-pressure refrigerant in the refrigeration cycle is sucked into the compressor 21, compressed to the 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 connection 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 dissipates heat. As a result, the indoor 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 connection pipe 4 and is reduced in pressure to the low pressure in the refrigeration cycle. The low-pressure refrigerant reduced in pressure in 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 that has evaporated in the outdoor heat exchanger 24 is sucked back into the compressor 21 through the four-way switching valve 23. In this way, during heating operation, the control device 6 causes the refrigerant sealed in the refrigerant circuit 10 to circulate through the compressor 21, indoor heat exchanger 31, expansion valve 25, and outdoor heat exchanger 24 in that order.

During heating operation, the control device 6 performs capacity control to control the capacity of the compressor 21 so that the condensation temperature Tc of the refrigerant in the refrigerant circuit 10 approaches a predetermined target condensation temperature Tcs. The capacity control of the compressor 21 is performed by controlling the rotation speed (frequency) of the motor 22.

The specified target condensation temperature is determined, for example, by the temperature difference between the indoor temperature Tr detected by the indoor temperature sensor 34 and the set temperature Trs set by the occupant through the remote control operation unit 64 of the remote control 60.

The refrigerant condensation temperature Tc is obtained by converting the discharge pressure detected by the discharge pressure sensor 29a to the refrigerant saturation temperature. The refrigerant condensation temperature Tc means the temperature obtained by converting the pressure (the refrigerant condensation pressure in the refrigerant circuit 10) representative of the high-pressure refrigerant flowing from the discharge side of the compressor 21 through the indoor heat exchanger 31 to the expansion valve 25 during heating operation, or the refrigerant saturation temperature in the indoor heat exchanger 31 that functions as a refrigerant radiator. Therefore, if a temperature sensor is provided in the indoor heat exchanger 31, the refrigerant temperature detected by this temperature sensor may be used as the refrigerant condensation temperature Tc.

(3-2) Cooling operation The cooling operation is performed by the control device 6, which receives a command for cooling operation via the remote control operation unit 64, controlling the operation of the compressor 21, four-way switching valve 23, expansion valve 25, outdoor fan 26, indoor fan 32, opening/closing member 49, etc., which are the components of the outdoor unit 2 and the indoor unit 3.

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

In the refrigerant circuit 10 in this state, the low-pressure refrigerant in the refrigeration cycle is sucked into the compressor 21, compressed to the 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 dissipates heat. The high-pressure refrigerant that has dissipated heat in the outdoor heat exchanger 24 is sent to the expansion valve 25 and reduced in pressure to the low pressure in the refrigeration cycle. The low-pressure refrigerant reduced in pressure in the expansion valve 25 is sent to the indoor heat exchanger 31 through the liquid refrigerant connection 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 and evaporates. As a result, the indoor air is cooled and blown out into the room. The low-pressure refrigerant evaporated in the indoor heat exchanger 31 is sucked back into the compressor 21 through the gas refrigerant connection pipe 5 and the four-way switching valve 23. In this way, during cooling operation, the control device 6 circulates the refrigerant sealed in the refrigerant circuit 10 through the compressor 21, the outdoor heat exchanger 24, the expansion valve 25, and the indoor heat exchanger 31 in that order.

During cooling operation, the control device 6 performs capacity control to control the capacity of the compressor 21 so that the evaporation temperature Te of the refrigerant in the refrigerant circuit 10 approaches a predetermined target evaporation temperature Teds. The capacity control of the compressor 21 is performed by controlling the rotation speed (frequency) of the motor 22.

The predetermined target evaporation temperature Teds is determined, for example, by the temperature difference between the indoor temperature Tr detected by the indoor temperature sensor 34 and the set temperature Trs set by the occupant through the remote control operation unit 64 of the remote control 60.

The refrigerant evaporation temperature Te is obtained by converting the suction pressure detected by the suction pressure sensor 28a to the saturation temperature of the refrigerant. The refrigerant evaporation temperature Te means the temperature obtained by converting the pressure (evaporation pressure of the refrigerant in the refrigerant circuit 10) representative of the low-pressure refrigerant in the refrigeration cycle that flows from the outlet of the expansion valve 25 through the indoor heat exchanger 31 to the suction side of the compressor 21 during cooling operation to the saturation temperature of the refrigerant, or the saturation temperature of the refrigerant in the indoor heat exchanger 31 that functions as an evaporator of the refrigerant. Therefore, if a temperature sensor is provided in the indoor heat exchanger 31, the temperature of the refrigerant detected by this temperature sensor may be used as the evaporation temperature Te of the refrigerant.

(3-3) Dehumidification operation The dehumidification operation is performed by the control device 6, which has received a command for dehumidification operation via the remote control operation unit 64, controlling the operation of the compressor 21, four-way switching valve 23, expansion valve 25, outdoor fan 26, indoor fan 32, opening/closing member 49, etc., which are components of the outdoor unit 2 and the indoor unit 3.

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

In the refrigerant circuit 10 in this state, the low-pressure refrigerant in the refrigeration cycle is sucked into the compressor 21, compressed to the 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 dissipates heat. The high-pressure refrigerant that has dissipated heat in the outdoor heat exchanger 24 is sent to the expansion valve 25 and reduced in pressure to the low pressure in the refrigeration cycle. The low-pressure refrigerant reduced in pressure in the expansion valve 25 is sent to the indoor heat exchanger 31 through the liquid refrigerant connection 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 and evaporates. As a result, the indoor air is dehumidified and blown out into the room. The low-pressure refrigerant that has evaporated in the indoor heat exchanger 31 is sucked back into the compressor 21 through the gas refrigerant connection pipe 5 and the four-way switching valve 23. In this way, during dehumidification operation, the control device 6 causes the refrigerant sealed in the refrigerant circuit 10 to circulate through the compressor 21, outdoor heat exchanger 24, expansion valve 25, and indoor heat exchanger 31 in that order.

The capacity control of the compressor 21 during dehumidification operation is the same as the capacity control of the compressor 21 during cooling operation, except that the target evaporation temperature Tecs during cooling operation is set as the target evaporation temperature Teds. The target evaporation temperature Teds during dehumidification operation is set to a value equal to or lower than the target evaporation temperature Tecs during cooling operation.

(4) Control of Opening/Closing Members The indoor control unit 30 controls the posture of the multiple opening/closing members 49. In other words, the indoor control unit 30 controls the opening and closing of the air outlets 46 of the multiple opening/closing members 49. The indoor control unit 30 controls the posture of the opening/closing member 49 so as to close at least one of the multiple air outlets 46 during low-load operation where the load of the air conditioning operation is equal to or lower than a predetermined value.

Here, "low-load operation" is an operation in which a substitute value indicating the load during air conditioning operation satisfies a specified condition. Unlike thermo-off, which stops the compressor 21 and stops the circulation of the refrigerant, low-load operation is performed before the thermo-off state. In addition, low-load operation does not include the start-up of the compressor 21, which starts operation, but is performed when the refrigerant state after startup is stable (operation that continues for a specified period of time).

For example, the substitute value is the rated capacity of the air conditioning device 1, and the specified condition is 45% or less of the rated capacity. In other words, low-load operation occurs when the capacity is 45% or less of the rated capacity. The rated capacity is the same value as the "nominal capacity" listed in the product catalog or instruction manual.

For example, the substitute value during cooling operation is the difference between the set temperature and the room temperature, and the specified condition is that this difference (set temperature Trs - room temperature Tr during heating operation, and room temperature Tr - set temperature Trs during cooling operation) is 0.5°C or less (including negative values). In other words, when the room temperature approaches the set temperature and the difference between the set temperature and the room temperature is 0.5°C or less, low-load operation is initiated.

For example, the substitute value during dehumidification operation is the difference between the set humidity and the indoor humidity, and the specified condition is that this difference is 0% or less. In other words, when the indoor humidity approaches the set humidity and the difference between the set humidity and the indoor humidity becomes 0% or less, low-load operation is initiated.

The indoor control unit 30 controls the rotation speed of the indoor fan 32 during low-load operation so that it is lower than the rotation speed of the indoor fan 32 during normal operation, in which the load of air conditioning operation is greater than that during low-load operation. In this embodiment, during low-load operation, the air volume of the indoor fan 32 is controlled to air volume LL, which cannot be set by the resident using the remote control 60.

(4-1) Control of opening/closing member during heating operation Next, a specific example of control of the opening/closing member 49 by the indoor control unit 30 during heating operation will be described with reference to Fig. 5. Fig. 5 shows the control by the indoor control unit 30 during low load operation. In Fig. 5, the lower limit of the condensation temperature Tc that does not give a feeling of cold air during heating operation is set to the first threshold value X (cold air line). Here, the target condensation temperature Tcs is set to be equal to or higher than the first threshold value X. Note that the condensation degree Tc is calculated from the discharge pressure detected by the discharge pressure sensor 29a, as described above.

In FIG. 5, at time t0, the indoor temperature Tr is rising. When the difference (Trs-Tr) between the indoor temperature Tr and the set temperature Trs (the target indoor temperature set by the remote control operation unit 64) becomes smaller, the target condensation temperature Tcs becomes lower and the rotation speed of the compressor 21 becomes smaller. Then, the refrigerant condensation temperature Tc becomes lower so as to approach the target condensation temperature Tcs.

After that, at time t1, when the target condensation temperature Tcs reaches the first threshold value X, the target condensation temperature Tcs is maintained at the first threshold value X so as not to give the feeling of cold air. As the rotation speed of the compressor 21 becomes further reduced, the condensation temperature Tc of the refrigerant decreases.

At time t2, when the refrigerant condensation temperature Tc reaches the first threshold value X, the indoor control unit 30 controls the position of the opening/closing member 49 to close at least one of the multiple air outlets 46. Here, at time t2, the indoor control unit 30 controls the position of the opening/closing member 49 to close at least one of the multiple air outlets 46 because the refrigerant condensation temperature Tc in the indoor heat exchanger 31 drops to the first threshold value X and the indoor temperature Tr continues to rise.

Here, the indoor control unit 30 performs independent wind direction control, which adjusts the wind direction of the conditioned air blown out from the four side air outlets 46a of the air outlets 46 independently by controlling each opening/closing member 49 to change its rotation state, and coordinated wind direction control, which adjusts the wind direction of the conditioned air blown out from the four side air outlets 46a of the air outlets 46 independently by controlling each opening/closing member 49 to change its rotation state. At time t2, in the independent wind direction control, the indoor control unit 30 rotates the opening/closing member 49 so as to close at least one of the multiple side air outlets 46a during low-load operation. As a result, the indoor fan 32 on the opening/closing member 49 side that closed the side air outlet 46a runs idle, and conditioned air is not blown out from the closed side air outlet 46a. Therefore, the indoor fan 32 can reduce the volume of conditioned air blown out from all the air outlets 46 while maintaining the rotation speed.

In this embodiment, the indoor control unit 30 controls at least one of the side air outlets 46a located in the direction facing the direction where no people are present to be closed by the opening/closing member 49. To perform such control, the indoor control unit 30 determines which opening/closing member 49 to close depending on the position of the person detected by the human detection sensor 36. In detail, the indoor control unit 30 controls the attitude of the opening/closing member 49 so as to keep the side air outlets 46a facing the direction where the person is present detected by the human detection sensor 36 open, and to close the side air outlets 46a facing the direction where no people are present. For example, when the conditioned air blown out from one of the four side air outlets 46a faces the direction where no people are present, the indoor control unit 30 rotates the opening/closing member 49 so as to reduce the amount of conditioned air blown out from that side air outlet 46a (preferably no conditioned air is blown out).

By controlling in this way, the amount of heat dissipated in the indoor heat exchanger 31 is reduced, and the condensation temperature Tc of the refrigerant can be increased. This prevents the temperature of the conditioned air blown out from the side air outlet 46a from becoming too low. In addition, low-load operation can be continued with the rotation speed of the compressor 21 further reduced without the thermostat being turned off.

If low-load operation continues after time t2, the condensation temperature Tc of the refrigerant will further decrease. When the condensation temperature reaches the first threshold value X again at time t3, the indoor control unit 30 controls the position of the multiple opening and closing members 49 so that the opening and closing members 49 close at least one of the air outlets 46 other than the air outlet 46 that was closed at time t2.

For example, at time t2, one of the four side air outlets 46a is closed by the opening/closing member 49, and three side air outlets 46a are opened. Then, at time t3, one of the three side air outlets 46a opened at time t2 is closed by the opening/closing member 49. As a result, after time t3 has elapsed, low-load operation can be continued with the rotation speed of the compressor 21 further reduced, without the thermostat being turned off.

(4-2) Control of opening/closing member during cooling operation Next, a specific example of control of the opening/closing member 49 of the indoor control unit 30 during cooling operation will be described with reference to Fig. 6. Fig. 6 shows the control by the indoor control unit 30 during low load operation. In Fig. 6, the lower limit of the evaporation temperature that does not give a feeling of warm air during cooling operation is set to a second threshold value Y (warm air line). Here, the target evaporation temperature Tecs is set to be equal to or lower than the second threshold value Y.

In this embodiment, the second threshold Y is the dew point temperature of the indoor air. The dew point temperature is calculated from the indoor temperature Tr detected by the indoor temperature sensor 34 and the indoor humidity Hr detected by the indoor humidity sensor 35. As described above, the evaporation temperature Te is calculated from the suction pressure detected by the suction pressure sensor 28a.

In FIG. 6, at time t0, the indoor temperature Tr is decreasing. When the difference (Trs-Tr) between the indoor temperature Tr and the set temperature Trs (the target indoor temperature set by the remote control operation unit 64) and the indoor temperature Tr becomes smaller, the target evaporation temperature Tecs becomes higher and the rotation speed of the compressor 21 becomes smaller. Then, the evaporation temperature Te of the refrigerant becomes higher so as to approach the target evaporation temperature Tecs.

After that, at time t1, when the target evaporation temperature Tecs reaches the second threshold Y, the target evaporation temperature Tecs is maintained at the second threshold Y so as not to give the feeling of warm air. As the rotation speed of the compressor 21 becomes smaller, the evaporation temperature Te of the refrigerant rises.

At time t2, when the refrigerant evaporation temperature Te reaches the second threshold Y, the indoor control unit 30 controls the position of the opening/closing member 49 to close at least one of the multiple air outlets 46. Here, at time t2, the indoor control unit 30 controls the position of the opening/closing member 49 to close at least one of the multiple air outlets 46 because the refrigerant evaporation temperature Te in the indoor heat exchanger 31 rises to the second threshold Y and the indoor temperature Tr continues to fall.

Specifically, similar to the heating operation, the indoor control unit 30 rotates the opening/closing member 49 to close at least one of the multiple air outlets 46 in independent air direction control. The indoor control unit 30 also controls the opening/closing member 49 to close at least one of the air outlets 46 located in a direction facing the direction in which no people are present.

By controlling in this way, the amount of heat absorbed in the indoor heat exchanger 31 is reduced, and the evaporation temperature Te of the refrigerant can be lowered. This makes it possible to prevent the temperature of the conditioned air blown out from the air outlet 46a from becoming too high. In addition, low-load operation can be continued with the rotation speed of the compressor 21 further reduced without the thermostat being turned off.

When low-load operation continues, the rotation speed of the compressor 21 becomes even smaller, so that the evaporation temperature Te of the refrigerant falls further. When the evaporation temperature reaches the second threshold Y again at time t3, the indoor control unit 30 controls the position of the multiple opening and closing members 49 so that the opening and closing members 49 close at least one of the air outlets 46 other than the air outlet 46 that was closed at time t2. This makes it possible to continue low-load operation with the rotation speed of the compressor 21 further reduced without thermo-off after time t3 has elapsed.

(4-3) Control of the opening/closing member during dehumidification operation The control of the opening/closing member 49 during dehumidification operation is basically the same as the control of the opening/closing member 49 during cooling operation, except that the target evaporation temperature Teds during dehumidification operation is set to a value lower than the target evaporation temperature Tecs during cooling operation.

(5) Method for Controlling the Opening and Closing Member The control of the opening and closing member has been mentioned in (4) above, but to summarize, the method involves the following steps.

First, as shown in FIG. 7, the compressor 21 is started and normal operation is performed with a higher load than during low-load operation (step S1). After that, when the load of the air conditioning operation falls below a predetermined level, low-load operation is performed (step S2).

Next, the indoor control unit 30 determines whether or not the draft feeling has been sufficiently suppressed (step S3). In this embodiment, in step S3, it is determined that the draft feeling has been sufficiently suppressed if the condensation temperature Tc of the refrigerant in the indoor heat exchanger 31 has not dropped to the first threshold value X during heating operation, and if the evaporation temperature Te of the refrigerant in the indoor heat exchanger 31 has not risen to the second threshold value Y during cooling operation or dehumidification operation. If it is determined in step S3 that the draft feeling has been sufficiently suppressed, the air outlet 46 is maintained in an open/closed state and low-load operation is continued (step S2).

On the other hand, in step S3, if the condensation temperature Tc falls to the first threshold value X during heating operation, or if the evaporation temperature Te rises to the second threshold value Y during cooling operation or dehumidification operation, it is determined that the draft feeling has not been sufficiently suppressed. If it is determined in step S3 that the draft feeling has not been sufficiently suppressed, the process proceeds to step S4.

In step S4, the indoor control unit 30 controls the position of the opening/closing member 49 to close at least one of the multiple air outlets 46. This makes it possible to prevent conditioned air with a cool feel from being blown out from the air outlet 46 during heating operation, and to prevent conditioned air with a warm feel from being blown out from the air outlet 46 during cooling operation or dehumidification operation. Therefore, the indoor unit 3 continues low-load operation (step S2).

In step S3 after at least one air outlet 46 is closed by the opening/closing member 49, if the condensation temperature Tc falls again to the first threshold value X during heating operation, or if the evaporation temperature Te rises again to the second threshold value Y during cooling operation or dehumidification operation, the indoor control unit 30 controls the attitude of the opening/closing member 49 so that the opening/closing member 49 closes at least one of the air outlets 46 that was closed by the opening/closing member 49 and another opening/closing member 49. This makes it possible to prevent conditioned air with a cool air feeling from being blown out from the air outlet 46 during heating operation, and to prevent conditioned air with a warm air feeling from being blown out from the air outlet 46 during cooling operation or dehumidification operation. Therefore, the indoor unit 3 continues low-load operation (step S2).

If it is determined in step S3 that the draft feeling is not sufficiently suppressed and all of the opening/closing members 49 are closing the air outlet 46, the control device 6 controls the air conditioning device 1 to enter thermo-off operation or to stop operation.

(6) Features (6-1)
In recent years, due to improvements in insulation performance, during air conditioning operation, the indoor temperature approaches the set temperature, and low-load operation with the air conditioning load below a predetermined level may be performed. However, during this low-load operation, there is a problem that the occupants feel a sense of draft. The inventors focused on this issue and conducted extensive research, resulting in the idea of the indoor unit 3 of the air conditioner 1 of this embodiment.

The indoor unit 3 of the air conditioner 1 according to this embodiment is an indoor unit of an air conditioner that performs air conditioning operation, and includes an indoor heat exchanger 31, a casing 41, multiple opening/closing members 49, and an indoor control unit 30. The indoor heat exchanger 31 exchanges heat between indoor air and a refrigerant to generate conditioned air. The casing 41 is formed with multiple air outlets 46, 46a, 46b that blow out the conditioned air. The multiple opening/closing members 49 open and close the multiple air outlets 46a. The indoor control unit 30 controls the attitude of the opening/closing member 49. The indoor control unit 30 controls the attitude of the opening/closing member 49 so as to close at least one of the multiple air outlets 46a during low-load operation where the load of the air conditioning operation is equal to or lower than a predetermined load.

In this embodiment, during low-load operation in which the air conditioning load is lower than in normal operation, the attitude of the opening/closing member 49 is controlled to close at least one of the air outlets 46a. This reduces the amount of heat exchanged between the refrigerant and the indoor air in the indoor heat exchanger 31. This prevents the temperature of the conditioned air blown out from the air outlet 46 from decreasing during heating operation, and prevents the temperature of the conditioned air blown out from the air outlet from increasing during cooling operation or dehumidification operation. This prevents the occupants from feeling cold air during heating operation of the air conditioning device 1, and prevents the occupants from feeling warm air during cooling operation or dehumidification operation. Thus, the indoor unit 3 can suppress a draft feeling.

(6-2)
Here, when the condensation temperature Tc of the refrigerant in the indoor heat exchanger 31 drops to the first threshold value X during heating operation (times t2 and t3 in Figure 5), the indoor control unit 30 controls the posture of the opening/closing member 49 to close at least one of the multiple air outlets 46a.

When the condensation temperature Tc of the refrigerant drops during heating operation, the temperature of the conditioned air that has exchanged heat with the refrigerant in the indoor heat exchanger 31 drops. For this reason, the first threshold value X is set to a lower limit value that does not give the feeling of cold air during heating operation, and when the condensation temperature Tc drops to the first threshold value, the opening and closing member 49 is controlled to close at least one of the air outlets 46a. This causes the condensation temperature Tc to rise, making it possible to prevent the conditioned air blown out of the air outlet 46a from dropping to a temperature that gives the feeling of cold air during heating operation.

In addition, by controlling the position of the opening/closing member 49, the condensation temperature Tc can be controlled so that the thermostat does not turn off. Therefore, the indoor unit 3 of this embodiment can reduce the frequency with which the thermostat turns off during low-load operation.

(6-3)
In addition to the above, here, the indoor control unit 30 controls the posture of the opening/closing member 49 to close at least one of the multiple air outlets 46a when the condensation temperature Tc of the refrigerant in the indoor heat exchanger 31 drops to the first threshold value X during heating operation and the temperature of the indoor air continues to rise (time t2 in Figure 5).

In this way, when the indoor air temperature rises during heating operation, the heating load becomes lower, and the temperature of the conditioned air that has been heat exchanged in the indoor heat exchanger 31 is likely to fall. Therefore, when the condensation temperature Tc falls during heating operation and the indoor air temperature rises, the indoor control unit 30 can close at least one of the air outlets 46a with the opening/closing member 49 to enhance the effect of suppressing the feeling of cold air.

(6-4)
Here, the indoor control unit 30 controls the posture of the opening/closing member 49 to close at least one of the multiple air outlets 46a when the evaporation temperature Te of the refrigerant in the indoor heat exchanger 31 rises to the second threshold value Y (times t2 and t3 in Figure 6) during cooling operation or dehumidification operation.

When the refrigerant evaporation temperature Te drops during cooling or dehumidification operation, the temperature of the conditioned air that has undergone heat exchange in the indoor heat exchanger 31 rises. For this reason, here, the second threshold Y is set to an upper limit value that does not give the feeling of warm air during cooling or dehumidification operation, and when the evaporation temperature Te rises to the second threshold Y, the position of the opening/closing member 49 is controlled to close at least one of the air outlets 46a. This makes it possible to prevent the conditioned air blown out of the air outlets 46a from rising to a temperature that gives the feeling of warm air during cooling or dehumidification operation.

In addition, by controlling the position of the opening/closing member 49, the evaporation temperature Te can be controlled so that the thermostat does not turn off. Therefore, the indoor unit 3 of this embodiment can reduce the frequency with which the thermostat turns off during low-load operation.

(6-5)
In addition to the above, when the evaporation temperature Te of the refrigerant in the indoor heat exchanger 31 rises to the second threshold value Y during cooling operation or dehumidification operation and the temperature of the indoor air continues to decrease (time t2 in Figure 6), the posture of the opening/closing member 49 is controlled to close at least one of the multiple air outlets 46a.

In this way, when the temperature or humidity of the indoor air decreases during cooling or dehumidification operation, the cooling load or dehumidification load becomes lower, so the temperature of the conditioned air that has undergone heat exchange in the indoor heat exchanger 31 is more likely to rise. Therefore, when the evaporation temperature Te rises and the temperature of the indoor air drops during cooling or dehumidification operation, the indoor control unit 30 can close at least one of the air outlets 46a with the opening and closing member 49, thereby enhancing the effect of suppressing the feeling of warm air.

(6-6)
Here, the second threshold value Y is the dew point temperature of the indoor air. In other words, when the evaporation temperature Te of the refrigerant in the indoor heat exchanger 31 rises to the dew point temperature during cooling operation or dehumidification operation, the indoor control unit 30 controls the attitude of the opening/closing member 49 to close at least one of the multiple air outlets 46a.

When the evaporation temperature Te of the refrigerant rises to the dew point temperature of the indoor air during cooling operation, the indoor air is no longer cooled to the refrigerant in the indoor heat exchanger 31. For this reason, the dew point temperature is set as the second threshold value Y here so that the indoor air is cooled to the refrigerant in the indoor heat exchanger 31. This makes it possible to perform cooling or dehumidification operation during low load operation while maintaining the refrigerant at or below the dew point temperature. Therefore, it is possible to realize an indoor unit that suppresses the sensation of warm air being given to the occupants during cooling or dehumidification operation.

In addition, during low-load operation in cooling and dehumidification, there is a problem of odor due to the lack of condensation. In this embodiment, when the evaporation temperature Te rises to the dew point temperature, at least one of the air outlets 46a is closed by the opening/closing member 49, so that the evaporation temperature Te does not exceed the dew point temperature. This makes it possible to suppress unpleasant odors caused by low-load operation.

(6-7)
Here, three or more air outlets 46a are formed in the casing 41. The indoor control unit 30 controls the attitudes of the multiple opening/closing members 49 so that, after closing at least one of the multiple air outlets 46a with the opening/closing member 49, at least one of the other air outlets 46a is closed with the opening/closing member 49.

In this way, the indoor control unit 30 of this embodiment can control the air conditioner to open the third air outlet 46a and close the second air outlet 46a with the opening/closing member 49 when the draft feeling is not sufficiently suppressed after opening the second and third air outlets 46a and closing the first air outlet 46a with the opening/closing member 49.

In addition, by having the multiple opening/closing members 49 close the three or more air outlets 46a at two or more times, the frequency with which the thermostat turns off during low-load operation can be further reduced.

(6-8)
Here, the indoor control unit 30 controls the opening/closing member 49 to close at least one of the air outlets 46a located in a direction facing a direction in which no people are present.

After at least one of the air outlets 46a is closed by the opening/closing member 49, conditioned air with a reduced draft feeling can be blown out. Therefore, comfort can be improved by supplying conditioned air with a reduced draft feeling in the direction where people are present.

(6-9)
Here, one opening/closing member 49 opens and closes one air outlet 46a. In other words, the first opening/closing member 49 opens and closes the first air outlet 46a, and the second opening/closing member 49 opens and closes the second air outlet 46a. This makes it easy to control the closing of the air outlet 46a by the opening/closing member 49.

(7) Modifications (7-1) Modification 1
In the above embodiment, among the air outlets 46, an opening/closing member 49 is arranged at each of the side air outlets 46a, and no opening/closing member 49 is arranged at the corner air outlets 46b, but this is not limited to the above. For example, in the above embodiment, one opening/closing member 49 is arranged at one side air outlet 46a, but two or more opening/closing members may be arranged at one side air outlet 46a. Also, one or more opening/closing members 49 may be arranged at the corner air outlets 46b.

(7-2) Modification 2
In the above embodiment, the attitude of the opening/closing member 49 is controlled to close at least one of the multiple air outlets 46 when the condensation temperature Tc falls to the first threshold value X during heating operation and when the evaporation temperature Te rises to the second threshold value Y during cooling operation or dehumidification operation, but this is not limited to this. The indoor control unit 30 controls the attitude of the opening/closing member 49 to close at least one of the multiple air outlets 46 at any timing from the start to the end of low-load operation. For this reason, the indoor control unit 30 may control the attitude of the opening/closing member 49 to close at least one of the multiple air outlets 46 before the condensation temperature Tc falls to the first threshold value X during heating operation and/or before the evaporation temperature Te rises to the second threshold value Y during cooling operation or dehumidification operation.

In this modified example, when the target condensation temperature Tcs falls to the first threshold value X during heating operation, and when the target evaporation temperatures Tecs, Teds rise to the second threshold value Y during cooling operation or dehumidification operation, the position of the opening/closing member 49 is controlled to close at least one of the multiple air outlets 46.

(7-3) Modification 3
In the above embodiment, the indoor control unit 30 closes one side air outlet 46a with the opening/closing member 49, continues low-load operation, and then closes another side air outlet 46a with another opening/closing member 49 when the condensation temperature Tc drops to the first threshold value X during heating operation, or when the evaporation temperature Te rises to the second threshold value Y during cooling operation or dehumidification operation, but is not limited to this. In this modified example, the indoor control unit 30 closes one side air outlet 46a with the opening/closing member 49, continues low-load operation, and then closes another side air outlet 46a with another opening/closing member 49 when the room temperature rises during heating operation (before the condensation temperature Tc drops to the first threshold value X) or when the room temperature drops during cooling operation or dehumidification operation (before the evaporation temperature Te rises to the second threshold value Y).

(7-4) Modification 4
In the embodiment described above, the indoor unit 3 is equipped with the human detection sensor 36, but this is not limited to this. The indoor unit 3 of this modified example does not include the human detection sensor 36. In this modified example, even if the human detection sensor 36 is not provided, the indoor control unit 30 closes the air outlet 46 that blows out conditioned air in a direction estimated to be a direction in which no people are present, using the opening and closing member 49, during low load operation.

(7-5) Modification 5
In the embodiment described above, the indoor control unit 30 controls at least one of the air outlets located in a direction facing a direction in which no one is present to be closed by the opening and closing member 49, but is not limited to this. The indoor control unit 30 can appropriately select the air outlet 46 to be closed during low-load operation.

(7-6) Modification 6
In the above-described embodiment, the state variable of the control target in the capacity control of the compressor 21 during cooling operation and dehumidification operation is the evaporation temperature Te, but this is not limited to this. In this modified example, the state variable of the control target in the capacity control is the evaporation pressure. In this case, a target evaporation pressure equivalent to the target evaporation temperatures Teds and Tecs is used as the control target value. Note that using the evaporation pressure and the target evaporation pressure in this capacity control is the same as using the evaporation temperature Te and the target evaporation temperatures Teds and Tecs.

(7-7) Modification 7
In the above-described embodiment, the state variable of the control object in the capacity control of the compressor 21 during heating operation is the condensing temperature Tc, but this is not limited to this. In this modified example, the state variable of the control object in the capacity control is the condensing pressure. In this case, a target condensing pressure equivalent to the target condensing temperature Tcs is used as the control target value. Note that using the condensing pressure and the target condensing pressure in this capacity control is the same as using the condensing temperature Tc and the target condensing temperature Tcs.

(7-8) Modification 8
In the above-described embodiment, the indoor unit 3 of the air conditioning device 1 that performs cooling operation, dehumidification operation, and heating operation has been described as an example, but the indoor unit of the present disclosure is not limited to this as long as it performs at least one of heating operation, cooling operation, and dehumidification operation.

(7-9) Modification 9
In the above-described embodiment, a ceiling-embedded indoor unit has been described as an example, but the indoor unit of the present disclosure is not limited to this. The indoor unit of the present disclosure may be of any type, such as a wall-mounted type or a floor-standing type.

(7-10) Modification 10
In the above-described embodiment, an air conditioner 1 including one indoor unit 3 has been described as an example, but the air conditioner of the present disclosure is not limited to this. The air conditioner of the present disclosure can also be applied to a multi-type air conditioner including multiple indoor units 3.

Although the embodiments of the present disclosure have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the present disclosure as set forth in the claims.

1: Air conditioner 2: Outdoor unit 3: Indoor unit 30: Indoor control unit (control unit)
41: Casing 45: Inlet 46, 46a, 46b: Outlet 49: Opening/closing member X: First threshold Y: Second threshold

JP 2011-99613 A

Claims (10)

An indoor unit of an air conditioner that performs air conditioning operation,
A heat exchanger (31) that exchanges heat between indoor air and a refrigerant to generate conditioned air;
a casing (41) in which a plurality of air outlets (46, 46a, 46b) for blowing out the conditioned air are formed;
A plurality of opening/closing members (49) for opening and closing the plurality of air outlets (46a);
A control unit (30) that controls the attitude of the opening/closing member;
Equipped with
the control unit controls the attitude of the opening/closing member to close at least one of the plurality of air outlets during low-load operation where the load of the air conditioning operation is equal to or lower than a predetermined value,
The control unit controls the attitude of the opening/closing member to close at least one of the plurality of air outlets when a condensation temperature of the refrigerant in the heat exchanger falls to a first threshold value and a temperature of the indoor air continues to rise during a heating operation .
An indoor unit (3) of an air conditioning device (1). An indoor unit of an air conditioner that performs air conditioning operation,
A heat exchanger (31) that exchanges heat between indoor air and a refrigerant to generate conditioned air;
a casing (41) in which a plurality of air outlets (46, 46a, 46b) for blowing out the conditioned air are formed;
A plurality of opening/closing members (49) for opening and closing the plurality of air outlets (46a);
A control unit (30) that controls the attitude of the opening/closing member;
Equipped with
the control unit controls the attitude of the opening/closing member to close at least one of the plurality of air outlets during low-load operation where the load of the air conditioning operation is equal to or lower than a predetermined value,
the control unit controls the attitude of the opening/closing member to close at least one of the plurality of air outlets when an evaporation temperature of the refrigerant in the heat exchanger rises to a second threshold value and a temperature of the indoor air continues to decrease during a cooling operation or a dehumidification operation.
An indoor unit (3) of an air conditioning device (1) . The second threshold value is a dew point temperature of indoor air.
An indoor unit for an air conditioner according to claim 2 . An indoor unit of an air conditioner that performs air conditioning operation,
A heat exchanger (31) that exchanges heat between indoor air and a refrigerant to generate conditioned air;
a casing (41) in which a plurality of air outlets (46, 46a, 46b) for blowing out the conditioned air are formed;
A plurality of opening/closing members (49) for opening and closing the plurality of air outlets (46a);
A control unit (30) that controls the attitude of the opening/closing member;
Equipped with
the control unit controls the attitude of the opening/closing member to close at least one of the plurality of air outlets during low-load operation where the load of the air conditioning operation is equal to or lower than a predetermined value,
The control unit controls the opening/closing member to close at least one of the air outlets located in a direction facing a direction in which no person is present.
An indoor unit (3) of an air conditioning device (1) . The control unit controls the attitude of the opening/closing member to close at least one of the plurality of air outlets when a condensation temperature of the refrigerant in the heat exchanger falls to a first threshold during a heating operation.
An indoor unit for an air conditioner according to claim 4 . The control unit controls the attitude of the opening/closing member to close at least one of the plurality of air outlets when a condensation temperature of the refrigerant in the heat exchanger falls to the first threshold value and a temperature of the indoor air continues to rise during a heating operation.
An indoor unit for an air conditioner according to claim 5 . the control unit controls the attitude of the opening/closing member to close at least one of the plurality of air outlets when an evaporation temperature of the refrigerant in the heat exchanger rises to a second threshold during a cooling operation or a dehumidification operation.
An indoor unit for an air conditioner according to claim 4 . the control unit controls the attitude of the opening/closing member to close at least one of the plurality of air outlets when an evaporation temperature of the refrigerant in the heat exchanger rises to the second threshold value and a temperature of the indoor air continues to decrease during a cooling operation or a dehumidification operation.
An indoor unit for an air conditioner according to claim 7 . The casing is formed with three or more of the air outlets,
The control unit controls the attitudes of the plurality of opening/closing members so that, after closing at least one of the plurality of air outlets with the opening/closing member, at least one of the other air outlets is closed with the opening/closing member.
An indoor unit for an air conditioner according to any one of claims 1 to 8 . One of the opening/closing members opens and closes one of the air outlets.
An indoor unit for an air conditioner according to any one of claims 1 to 9 .

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