Air Conditioning Equipment

Abstract

To suppress retention of warm air at an upper part in a room while preventing an occupant from having draft feeling.SOLUTION: A control section 40 controls an indoor fan 34 in a manner mentioned below, when a temperature Th of an indoor heat exchanger 32 is a first temperature Ta or lower when a substitute value indicating a load during a heating operation satisfies a prescribed condition. The indoor fan 34 is rotated at a first rotating speed fa when an indoor temperature Tr is a second temperature Tb or lower. The indoor fan 34 is rotated at a second rotating speed fb higher than the first rotating speed fa when the indoor temperature Tr is over the second temperature Tb.SELECTED DRAWING: Figure 4

Description

[Technical field]

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

[0002] During heating operation by an air conditioner, when the indoor temperature approaches the set temperature, the occupants may feel a draft (cold air). This is caused by the indoor temperature approaching the set temperature and the temperature of the indoor heat exchanger dropping. To prevent this draft (cold air) feeling, for example, the air conditioner described in Patent Document 1 (Japanese Utility Model Publication No. 53-1632) controls the indoor fan to reduce its air volume when the indoor temperature approaches the set temperature. Summary of the Invention [Problem to be solved by the invention]

[0003] As a result, the air in the room becomes less agitated, and "warm air pockets" tend to form at the top of the room, making the thermostat more likely to turn off.

[0004] Therefore, there is a problem of how to prevent the occurrence of "warm air pockets" in the upper part of the room while minimizing the feeling of draft that is given to the occupants. [Means for solving the problem]

[0005] An air conditioner according to a first aspect is an air conditioner that performs heat exchange in an indoor heat exchanger between a high-temperature, high-pressure refrigerant discharged from a compressor and air taken in from an inlet by the rotation of an indoor fan, and sends out the air heated by the indoor heat exchanger from an outlet, thereby heating the room. The air conditioner includes a first temperature measurement unit, a second temperature measurement unit, and a control unit. The first temperature measurement unit measures the temperature in the room. The second temperature measurement unit measures the temperature of the indoor heat exchanger. The control unit controls the rotation speed of the indoor fan. Furthermore, when a substitute value indicating a load during heating operation satisfies a predetermined condition, if the temperature of the indoor heat exchanger is equal to or lower than a first temperature, the control unit controls the indoor fan as follows: when the indoor temperature is equal to or lower than a second temperature, the indoor fan is rotated at a first rotation speed. When the indoor temperature exceeds the second temperature, the indoor fan is rotated at a second rotation speed that is higher than the first rotation speed.

[0006] With this air conditioning system, when the indoor temperature rises, the blown air is less likely to give a draft feeling (a feeling of cold air) to the occupants even when it hits them. Therefore, by increasing the airflow of the indoor fan in line with the rise in indoor temperature, the air in the room is stirred up, and the occurrence of "warm air pockets" at the top of the room can be suppressed.

[0007] An air conditioner of a second aspect is the air conditioner of the first aspect, wherein the substitute value is the difference ΔT when the measured value is subtracted from the set value of the indoor temperature. And the predetermined condition is that the difference ΔT is 0° C. or less.

[0008] With this air conditioning system, if the difference △T when subtracting the measured value from the indoor temperature set value is below 0℃, the indoor temperature is stable. With conventional indoor fan airflow control, it is not possible to obtain an airflow volume sufficient to stir the indoor air. However, by increasing the indoor fan airflow in line with the rise in indoor temperature, the indoor air is stirred and the accumulation of warm air at the upper part of the room can be prevented.

[0009] An air conditioner according to a third aspect is the air conditioner according to the first aspect, in which the substitute value is an operating frequency fo of the compressor, and the predetermined condition is that the operating frequency fo is 20 Hz or less.

[0010] In this air conditioning system, if the compressor operating frequency fo is 20 Hz or less, the indoor temperature is stable, and with conventional indoor fan airflow control, it is not possible to obtain an airflow volume sufficient to stir the indoor air. However, by increasing the indoor fan airflow volume in line with the rise in indoor temperature, the indoor air is stirred and the occurrence of warm air pockets at the top of the room can be suppressed.

[0011] An air conditioner according to a fourth aspect is the air conditioner according to any one of the first to third aspects, wherein the first temperature measurement unit has a first temperature sensor that detects the temperature of air taken into the air inlet. The first temperature measurement unit uses a value detected by the first temperature sensor as a substitute for the room temperature.

[0012] This air conditioning apparatus is rational because it can utilize an existing temperature sensor.

[0013] An air conditioning apparatus according to a fifth aspect is the air conditioning apparatus according to any one of the first to third aspects, wherein the first temperature measurement unit has a radiation sensor that detects a radiation temperature in the room. The first temperature measurement unit uses a detection value of the radiation sensor as a substitute for the temperature in the room.

[0014] An air conditioner according to a sixth aspect is the air conditioner according to any one of the first aspect to the fifth aspect, wherein the second temperature measurement unit has a second temperature sensor attached to the indoor heat exchanger. The second temperature measurement unit uses a detection value of the second temperature sensor as a substitute for the temperature of the indoor heat exchanger.

[0015] This air conditioning apparatus is rational because it can utilize an existing temperature sensor.

[0016] An air conditioner according to a seventh aspect is the air conditioner according to any one of the first to fifth aspects, wherein the second temperature measurement unit has a third temperature sensor arranged in an air passageway extending from the indoor heat exchanger to the air outlet, and the control unit estimates the temperature of the indoor heat exchanger from a detection value of the third temperature sensor.

[0017] An air conditioner of an eighth aspect is the air conditioner of any one of the first aspect to the seventh aspect, wherein the lower limit of the first rotation speed is set according to the temperature of the indoor heat exchanger, and the lower limit of the first rotation speed when the indoor temperature is higher than the second temperature is higher than the lower limit of the first rotation speed when the indoor temperature is equal to or lower than the second temperature.

[0018] In this air conditioner, the higher the indoor temperature, the higher the minimum rotation speed of the indoor fan becomes. Therefore, under conditions of low heating load, the air in the room is agitated with an air volume appropriate for the indoor temperature, and the occurrence of warm air pockets can be suppressed.

[0019] An air conditioner of a ninth aspect is the air conditioner of any one of the first aspect to the eighth aspect, further comprising an air volume setting means for setting an air volume of the indoor fan. When the indoor temperature is higher than a second temperature, the control unit rotates the indoor fan at a rotation speed according to the air volume set by the air volume setting means.

[0020] In this air conditioner, since the feeling of draft varies from person to person, the occurrence of warm air pools is suppressed by setting the air volume preferred by the user using the air volume setting means.

[0021] An air conditioner according to a tenth aspect is the air conditioner according to any one of the first aspect to the ninth aspect, wherein the first temperature is set within a range of 18°C ​​to 35°C. [Brief description of the drawings]

[0022] [Figure 1] 1 is a configuration diagram of an air conditioning apparatus according to an embodiment of the present disclosure. [Diagram 2] 2 is a block diagram showing a control unit of the air conditioning apparatus. FIG. [Diagram 3] FIG. 4 is a cross-sectional view of the indoor unit during operation. [Figure 4] 4 is a flowchart of warm air accumulation suppression control. [Diagram 5] 1 is a table showing the rotation speed of the indoor fan according to the temperature of the indoor heat exchanger. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] (1) Configuration of Air Conditioner 1 Fig. 1 is a configuration diagram of an air conditioner 1 according to one embodiment of the present disclosure. In Fig. 1, the air conditioner 1 performs cooling and heating of a room. The air conditioner 1 includes an outdoor unit 2 installed outdoors and an indoor unit 3 installed indoors.

[0024] The outdoor unit 2 and the indoor unit 3 are connected to each other by two communication pipes 11, 12 to form a refrigerant circuit 10. In the refrigerant circuit 10, a vapor compression refrigeration cycle is performed by circulating a charged refrigerant.

[0025] The air conditioning apparatus 1 also includes a control unit 40. The control unit 40 includes an outdoor side control unit 41 mounted in the outdoor unit 2, and an indoor side control unit 42 mounted in the indoor unit 3. The indoor side control unit 42 is connected to a remote controller 50 wirelessly or via a wire.

[0026] A resident of the living space in which the indoor unit 3 is installed (hereinafter referred to as the “room”) can change the set temperature and air volume of the air conditioner 1 via the remote controller 50.

[0027] (1-1) Outdoor unit 2 The outdoor unit 2 includes a compressor 21, a four-way switching valve 22, an outdoor heat exchanger 23, and an outdoor expansion valve 24.

[0028] (1-1-1) Compressor 21 The compressor 21 compresses a low-pressure refrigerant and discharges the compressed high-pressure refrigerant. In the compressor 21, a compression mechanism such as a scroll type or a rotary type is driven by a motor 21m. The operating rotation speed of the motor 21m is changed by an inverter device.

[0029] (1-1-2) Four-way switching valve 22 The four-way switching valve 22 has first to fourth ports P1 to P4. In the four-way switching valve 22, the first port P1 is connected to the discharge side of the compressor 21, the second port P2 is connected to the suction side of the compressor 21 (specifically, to the accumulator 25), the third port P3 is connected to the gas side end of the outdoor heat exchanger 23, and the fourth port P4 is connected to the gas side stop valve 28.

[0030] The four-way switching valve 22 switches between a first state (a state shown by a solid line in FIG. 1) and a second state (a state shown by a dashed line in FIG. 1). In the first state of the four-way switching valve 22, the first port P1 communicates with the third port P3, and the second port P2 communicates with the fourth port P4.

[0031] In the four-way switching valve 22 in the second state, the first port P1 and the fourth port P4 communicate with each other, and the second port P2 and the third port P3 communicate with each other.

[0032] (1-1-3) Outdoor heat exchanger 23 The outdoor heat exchanger 23 is a fin-and-tube type heat exchanger. An outdoor fan 29 is installed near the outdoor heat exchanger 23. In the outdoor heat exchanger 23, air transported by the outdoor fan 29 and the refrigerant flowing inside the outdoor heat exchanger 23 exchange heat.

[0033] (1-1-4) Outdoor expansion valve 24 The outdoor expansion valve 24 is an electronic expansion valve with a variable opening degree. The outdoor expansion valve 24 is disposed downstream of the outdoor heat exchanger 23 in the direction of refrigerant flow in the refrigerant circuit 10 during cooling operation.

[0034] During cooling operation, the opening degree of the outdoor expansion valve 24 is adjusted so as to reduce the pressure of the refrigerant flowing into the indoor heat exchanger 32 to the evaporation pressure. During heating operation, the opening degree of the outdoor expansion valve 24 is adjusted so as to reduce the pressure of the refrigerant flowing into the outdoor heat exchanger 23 to the evaporation pressure.

[0035] (1-1-5) Outdoor control unit 41 As shown in Fig. 1, the outdoor unit 2 is equipped with an outdoor side control unit 41. Fig. 2 is a block diagram showing the control unit 40 of the air conditioning apparatus 1. In Fig. 2, the outdoor side control unit 41 has a built-in microcomputer 41a and a memory 41b. The microcomputer 41a performs various calculations and issues commands to devices to be controlled. The memory 41b stores various data.

[0036] (1-1-6) Outdoor fan 29 1, the outdoor fan 29 is composed of a propeller fan 29a and a motor 29b that drives the propeller fan 29a. The rotation speed of the motor 29b is variable by an inverter device.

[0037] (1-1-7) Liquid connection pipe 11 and gas connection pipe 12 The two connection pipes include a liquid connection pipe 11 and a gas connection pipe 12. The liquid connection pipe 11 has one end connected to the liquid side stop valve 27 and the other end connected to the liquid side end of the indoor heat exchanger 32.

[0038] The gas connection pipe 12 has one end connected to the gas side shutoff valve 28 and the other end connected to the gas side end of the indoor heat exchanger 32 .

[0039] (1-2) Indoor unit 3 3 is a cross-sectional view of the indoor unit 3 during operation. In FIG. 3, the indoor unit 3 includes a main body casing 30, an indoor heat exchanger 32, an indoor fan , and an indoor side control unit .

[0040] (1-2-1) Main casing 30 The main body casing 30 accommodates therein an indoor heat exchanger 32, an indoor fan 34, and an indoor control unit 42.

[0041] An intake port 310 is provided at an upper portion of the main casing 30. An exhaust port 311 is provided at a lower portion of the main casing 30.

[0042] Near the air outlet 311, airflow direction adjustment blades 36 (first airflow direction adjustment blade 361 and second airflow direction adjustment blade 362) for changing the direction of air blown out from the air outlet 311 are rotatably attached.

[0043] Moreover, the air outlet 311 is connected to the inside of the main body casing 30 by an air outlet passage 318. The air outlet passage 318 is formed from the air outlet 311 along a scroll 317 of a bottom frame 316. The indoor heat exchanger 32 and the indoor fan 34 are attached to the bottom frame 316.

[0044] In this embodiment, the indoor heat exchanger 32 is disposed in the air flow path connecting the suction port 310 and the air outlet 311. When the indoor fan 34 is operated, indoor air is sucked into the indoor fan 34 through the suction port 310 and the indoor heat exchanger 32, and is blown out of the indoor fan 34 through the air outlet flow path 318 and from the air outlet 311.

[0045] (1-2-2) Indoor heat exchanger 32 The indoor heat exchanger 32 is a fin-and-tube type heat exchanger that exchanges heat with the air passing through it. The indoor heat exchanger 32 has an inverted V shape with both ends bent downward in a side view, and an indoor fan 34 is located below it. The indoor heat exchanger 32 includes a first heat exchange section 321 and a second heat exchange section 322.

[0046] (1-2-3) Indoor fan 34 The indoor fan 34 is a cross-flow fan. The indoor fan 34 is located below the indoor heat exchanger 32, and blows air taken in from the room into the room after it passes through the indoor heat exchanger 32. The indoor fan 34 is composed of a horizontally long fan 34a and a motor 34b that drives the fan 34a. The rotation speed of the motor 34b is variable by an inverter device.

[0047] (1-2-4) First airflow direction adjustment blade 361 and second airflow direction adjustment blade 362 The first airflow direction adjustment blade 361 is driven by a motor (not shown) to swing and can take a number of positions with different inclination angles. The rotation axis of the first airflow direction adjustment blade 361 when swinging is provided on the upper end side of the air outlet 311.

[0048] The second airflow direction adjustment blade 362 is driven by a motor (not shown) to swing, and not only changes the direction of the blown air, but also opens and closes the air outlet 311. The second airflow direction adjustment blade 362 can take a number of positions with different inclination angles. The rotation axis around which the second airflow direction adjustment blade 362 swings is provided on the lower end side of the air outlet 311.

[0049] (1-2-5) Indoor control unit 42 As shown in Fig. 1, the indoor unit 3 is equipped with an indoor side control unit 42. Also, as shown in Fig. 2, the indoor side control unit 42 has a built-in microcomputer 42a and a memory 42b.

[0050] The microcomputer 42a performs various calculations in the indoor unit 3. In addition, the memory 42b stores various data.

[0051] In addition, the microcomputer 42a communicates control signals and the like with a remote controller 50 for individually operating the indoor units 3, and further communicates control signals and the like with the outdoor unit 2 via a transmission line.

[0052] (1-2-6) Various sensors The indoor unit 3 is provided with an indoor temperature sensor 61 and a heat exchanger temperature sensor 62. The indoor temperature sensor 61 is provided on the indoor air inlet side of the indoor unit 3. The indoor temperature sensor 61 measures the temperature of the indoor air flowing into the indoor unit 3 (hereinafter referred to as indoor temperature Tr).

[0053] The heat exchanger temperature sensor 62 is attached approximately at the center of the indoor heat exchanger 32 and measures the temperature of the refrigerant flowing through the indoor heat exchanger 32.

[0054] (1-3) Control unit 40 The control unit 40 controls the operation of the air conditioning apparatus 1 by coordinating an outdoor side control unit 41 of the outdoor unit 2 and an indoor side control unit 42 of the indoor unit 3. For example, the control unit 40 controls the operation of the entire air conditioning apparatus 1 by causing the microcomputers of the outdoor side control unit 41 and the indoor side control unit 42 to execute programs stored in their respective memories.

[0055] 2, the control unit 40 is communicatively connected to the indoor temperature sensor 61 and the heat exchanger temperature sensor 62. The control unit 40 is also electrically connected to the motor 34b of the indoor fan 34, the motor 21m of the compressor 21, the four-way switching valve 22, the outdoor expansion valve 24, the motor 26b of the outdoor fan 29, the motor of the first airflow direction adjustment blade 361, and the motor of the second airflow direction adjustment blade 362.

[0056] (2) Driving behavior Next, the operation of the air conditioner 1 according to this embodiment will be described. The air conditioner 1 switches between cooling operation and heating operation. Here, the heating operation and the cooling operation will be described in that order.

[0057] (2-1) Cooling operation 1 is in the state indicated by the solid line, and the compressor 21, the indoor fan 34, and the outdoor fan 29 are in operation. As a result, in the refrigerant circuit 10, a refrigeration cycle is performed in which the outdoor heat exchanger 23 serves as a condenser and the indoor heat exchanger 32 serves as an evaporator.

[0058] Specifically, the high-pressure refrigerant compressed by the compressor 21 flows through the outdoor heat exchanger 23 and exchanges heat with the outdoor air. In the outdoor heat exchanger 23, the high-pressure refrigerant dissipates heat to the outdoor air and condenses. The refrigerant condensed in the outdoor heat exchanger 23 is decompressed by the outdoor expansion valve 24 on the way to the indoor heat exchanger 32, and then flows through the indoor heat exchanger 32.

[0059] In the indoor unit 3, indoor air drawn in by the indoor fan 34 passes through the indoor heat exchanger 32 and exchanges heat with the refrigerant flowing inside the indoor heat exchanger 32. In the indoor heat exchanger 32, the refrigerant absorbs heat from the indoor air and evaporates, cooling the air. The air cooled by the indoor heat exchanger 32 is supplied to the indoor space. The refrigerant evaporated in the indoor heat exchanger 32 is sucked into the compressor 21 and compressed again.

[0060] (2-2) Heating operation 1 is in the state indicated by the dashed line, and the compressor 21, the indoor fan 34, and the outdoor fan 29 are in operation. As a result, in the refrigerant circuit 10, a refrigeration cycle is performed in which the indoor heat exchanger 32 serves as a condenser and the outdoor heat exchanger 23 serves as an evaporator.

[0061] Specifically, the high-pressure refrigerant compressed by the compressor 21 flows through the indoor heat exchanger 32. In the indoor unit 3, indoor air sucked in by the indoor fan 34 passes through the indoor heat exchanger 32 and exchanges heat with the refrigerant flowing through the indoor heat exchanger 32. In the indoor heat exchanger 32, the refrigerant releases heat to the indoor air and condenses, heating the air. The air heated by the indoor heat exchanger 32 is supplied to the indoor space. The refrigerant condensed in the indoor heat exchanger 32 is decompressed by the outdoor expansion valve 24, and then flows through the outdoor heat exchanger 23. In the outdoor heat exchanger 23, the refrigerant absorbs heat from the outdoor air and evaporates. The refrigerant evaporated in the outdoor heat exchanger 23 is sucked into the compressor 21 and compressed again.

[0062] (2-2-1) Thermo off and thermo on during heating operation Here, the thermo-off and thermo-on during heating operation will be described.

[0063] Thermo-off is a function that automatically stops the heating operation temporarily during heating operation according to the set temperature. Specifically, the control unit 40 temporarily stops the compressor 21 when the indoor temperature Tr exceeds the set temperature Ts and the absolute value of the difference ΔT obtained by subtracting the indoor temperature Tr from the set temperature Ts becomes larger than a predetermined value (e.g., 2K). At this time, the function of the indoor heat exchanger 32 as a condenser is also temporarily stopped.

[0064] Thermo-on is a function that automatically restarts the heating operation according to the set temperature Ts when the thermo-off state is reached. Specifically, the control unit 40 restarts the compressor 21 when the indoor temperature Tr falls below the set temperature Ts and the absolute value of the difference ΔT obtained by subtracting the indoor temperature Tr from the set temperature Ts becomes greater than a predetermined value (e.g., 2 K). At this time, the indoor heat exchanger 32 resumes its function as a condenser.

[0065] (2-2-2) Cold air suppression function by reducing the air volume during low-load heating operation During heating operation, if the temperature of the refrigerant flowing through the indoor heat exchanger 32 drops below a predetermined value, the occupant may feel cold when exposed to the air blown out from the air outlet 311, which is called a draft feeling.

[0066] Here, "when the temperature of the refrigerant flowing through the indoor heat exchanger 32 drops below a predetermined value" refers to, for example, when the air conditioner 1 is performing low-load heating operation.

[0067] In addition, low-load heating operation is an operation in which a substitute value indicating the load during heating operation satisfies a specified condition. In this embodiment, the substitute value is the difference ΔT obtained by subtracting the measured value from the set value of the indoor temperature, and the specified condition is that the difference ΔT is equal to or less than a specified value before the thermostat is turned off.

[0068] For example, when the set temperature Ts is 20°C, the temperature Th of the indoor heat exchanger 32 just before the thermostat is turned off will be 25°C to 30°C, and the temperature of the blown air will be lower than the temperature Th of the indoor heat exchanger 32, so that the occupants will feel cold when they are exposed to the blown air.

[0069] To prevent the occupant from feeling this draft, the control unit 40 reduces the rotation speed of the motor 34b of the indoor fan 34 and reduces the volume of air blown out from the air outlet 311. This function is the cold air suppression function. When the cold air suppression function is working, the volume of air is adjusted to, for example, the minimum volume of air that can be set.

[0070] (2-2-3) Suppression of warm air accumulation However, when the cold air suppression function is activated and the volume of air blown out from the air outlet 311 decreases, a "warm air pocket" in which warm air stagnates around the indoor unit 3 occurs.

[0071] When warm air accumulates, the temperature of the air around the indoor unit 3 becomes higher than the temperature of the air in the room other than around the indoor unit 3. Therefore, even if the temperature of the air in the room other than around the indoor unit 3 is low, the thermo-off may be erroneously executed.

[0072] Therefore, when the difference ΔT obtained by subtracting the indoor temperature Tr from the set temperature Ts is equal to or less than a predetermined value and the temperature Th of the indoor heat exchanger 32 is equal to or less than the first temperature Ta, the control unit 40 rotates the indoor fan 34 at the first rotation speed fa when the indoor temperature Tr is equal to or less than the second temperature Tb. Conversely, when the indoor temperature Tr exceeds the second temperature Tb, the control unit 40 rotates the indoor fan 34 at the second rotation speed fb that is greater than the first rotation speed fa.

[0073] 4 is a flowchart of the warm air pool suppression control. Hereinafter, the operation of the warm air pool suppression control will be described with reference to FIG.

[0074] (Step S1) In step S1, the control unit 40 reads the indoor set temperature Ts. The set temperature Ts is set by the occupant via the remote controller 50, and the set value is stored in the memory 42b of the indoor side control unit 42.

[0075] (Step S2) Next, the control unit 40 measures the room temperature Tr in step S2. In this embodiment, the room temperature Tr is substituted with the detection value of the room temperature sensor 61 provided on the indoor air inlet side of the indoor unit 3.

[0076] (Step S3) Next, in step S3, the control unit 40 determines whether the difference ΔT obtained by subtracting the room temperature Tr from the set temperature Ts is equal to or less than a predetermined value d. In this embodiment, d=0° C. If the difference ΔT is equal to or less than the predetermined value d, it is determined that the heating operation is a low-load operation, and the process proceeds to step S4.

[0077] (Step S4) Next, in step S4, the control unit 40 measures the temperature Th of the indoor heat exchanger 32. In this embodiment, the temperature Th of the indoor heat exchanger 32 is substituted for the detection value of the heat exchanger temperature sensor 62 attached approximately at the center of the indoor heat exchanger 32.

[0078] (Step S5) Next, in step S5, the control unit 40 determines whether or not the temperature Th of the indoor heat exchanger 32 is equal to or lower than Ta. If the temperature Th is equal to or lower than the first temperature Ta, the process proceeds to step S6.

[0079] (Step S6) Next, in step S6, the control unit 40 determines whether the room temperature Tr is equal to or lower than Tb. If the room temperature Tr is equal to or lower than Tb, the process proceeds to step S7, and if the room temperature Tr exceeds Tb, the process proceeds to step S8.

[0080] (Step S7) In step S7, the control unit 40 rotates the indoor fan 34 at the first rotation speed fa. As the heating operation has shifted to the low-load heating operation, the temperature Th of the indoor heat exchanger 32 is equal to or lower than the first temperature Ta, and the indoor temperature Tr is equal to or lower than the second temperature Tb, the occupant is likely to feel the blown air as cold. Therefore, the control unit 40 activates the cold air suppression function to rotate the indoor fan 34 at the first rotation speed fa to minimize the airflow.

[0081] (Step S8) Meanwhile, in step S8, the control unit 40 rotates the indoor fan 34 at a second rotation speed fb that is higher than the first rotation speed fa. As the heating operation transitions to the low-load heating operation, the temperature Th of the indoor heat exchanger 32 becomes equal to or lower than the first temperature Ta, and the indoor temperature Tr exceeds the second temperature Tb, the occupant does not easily feel that the blown air is cold.

[0082] Therefore, the control unit 40 rotates the indoor fan 34 at the second rotation speed fb to increase the airflow, agitate the air in the room, and prevent the occurrence of "warm air pockets" in the upper part of the room.

[0083] More specifically, the control unit 40 controls the air volume by changing the rotation speed of the indoor fan 34 according to the temperature Th of the indoor heat exchanger 32. Since the air volume of the indoor fan 34 can be set to four stages, from lowest to highest, namely, S tap, L tap, M tap, and H tap, when the cold air suppression function is working, even if the rotation speed is set to a default, if it is determined that the temperature Th of the indoor heat exchanger 32 is low, the rotation speed is changed to a low rotation speed corresponding to the L tap or S tap. Then, when the temperature of the blown air rises and it is determined that the occupant does not feel a draft or is unlikely to feel a draft, the control unit 40 increases the rotation speed of the indoor fan 34.

[0084] Fig. 5 is a table showing the rotation speed of the indoor fan 34 according to the temperature of the indoor heat exchanger 32. In Fig. 5, when the temperature Th of the indoor heat exchanger 32 is 20°C or less and the indoor temperature Tr is 18°C ​​or less, the lower limit of the rotation speed of the indoor fan 34 is the rotation speed fs1 corresponding to the S tap. Next, when the temperature Th of the indoor heat exchanger 32 is 20°C or less and the indoor temperature Tr is higher than 18°C, the lower limit of the rotation speed of the indoor fan 34 is the rotation speed fs1+α1.

[0085] Furthermore, when the temperature Th of the indoor heat exchanger 32 is 22° C. or less and the indoor temperature Tr is 20° C. or less, the lower limit of the rotation speed of the indoor fan 34 is the rotation speed fs2 corresponding to the S tap. Next, when the temperature Th of the indoor heat exchanger 32 is 22° C. or less and the indoor temperature Tr is above 20° C., the lower limit of the rotation speed of the indoor fan 34 is the rotation speed fs2+α2.

[0086] Furthermore, when the temperature Th of the indoor heat exchanger 32 is 24° C. or less and the indoor temperature Tr is 22° C. or less, the lower limit of the rotation speed of the indoor fan 34 is the rotation speed fs3 corresponding to the S tap. Next, when the temperature Th of the indoor heat exchanger 32 is 24° C. or less and the indoor temperature Tr is higher than 22° C., the lower limit of the rotation speed of the indoor fan 34 is the rotation speed fs3+α3.

[0087] Furthermore, when the temperature Th of the indoor heat exchanger 32 is 26° C. or less and the indoor temperature Tr is 24° C. or less, the lower limit of the rotation speed of the indoor fan 34 is the rotation speed fs4 corresponding to the S tap. Next, when the temperature Th of the indoor heat exchanger 32 is 26° C. or less and the indoor temperature Tr is higher than 24° C., the lower limit of the rotation speed of the indoor fan 34 is the rotation speed fs4+α4.

[0088] (3) Features (3-1) When the substitute value indicating the load during heating operation satisfies a predetermined condition, and the temperature Th of the indoor heat exchanger 32 is equal to or lower than the first temperature Ta, the control unit 40 controls the indoor fan 34 as follows: When the indoor temperature Tr is equal to or lower than the second temperature Tb, the control unit 40 rotates the indoor fan 34 at the first rotation speed fa. When the indoor temperature Tr exceeds the second temperature Tb, the control unit 40 rotates the indoor fan 34 at the second rotation speed fb that is higher than the first rotation speed fa.

[0089] Therefore, in the air conditioning device 1, when the indoor temperature Tr increases, the blown air is less likely to give a draft feeling (a feeling of cold air) to the occupants even when it hits them. Therefore, by increasing the airflow rate of the indoor fan 34 in accordance with the rise in the indoor temperature, the air in the room is stirred and the occurrence of "warm air pockets" in the upper part of the room can be suppressed.

[0090] (3-2) The substitute value is the difference ΔT when the measured value is subtracted from the set value of the indoor temperature, and the predetermined condition is that the difference ΔT is 0° C. or less.

[0091] Therefore, in air conditioning device 1, if the difference ΔT obtained by subtracting the measured value from the set indoor temperature is below 0°C, the indoor temperature is stable, and with conventional indoor fan airflow control, it is not possible to obtain an airflow volume sufficient to stir the indoor air. However, by increasing the airflow of indoor fan 34 in line with the rise in indoor temperature, the indoor air is stirred and the occurrence of warm air pockets at the upper part of the room can be suppressed.

[0092] (3-3) In the air conditioner 1, the detection value of the indoor temperature sensor 61 is used as a substitute for the indoor temperature, so that an existing temperature sensor can be utilized, which is rational.

[0093] (3-4) In the air conditioner 1, the detection value of the heat exchanger temperature sensor 62 is used as a substitute for the temperature of the indoor heat exchanger 32, so that an existing temperature sensor can be utilized, which is rational.

[0094] (3-5) The lower limit of the first rotation speed fa is set according to the temperature Th of the indoor heat exchanger 32. The lower limit of the first rotation speed when the indoor temperature Th is higher than the second temperature Tb is higher than the lower limit of the first rotation speed when the indoor temperature is equal to or lower than the second temperature Tb.

[0095] In the air conditioning device 1, the higher the indoor temperature, the higher the lower limit of the rotation speed of the indoor fan 34 becomes. Therefore, under conditions of low heating load, the indoor air is agitated with an air volume appropriate for the indoor temperature, making it possible to suppress the occurrence of warm air pockets.

[0096] (3-6) The control unit 40 rotates the indoor fan 34 at a rotation speed according to the air volume set by the remote controller 50 when the indoor temperature Tr is higher than the second temperature Tb.

[0097] In the air conditioning device 1, since the feeling of draft varies from person to person, the occurrence of warm air pockets is prevented by setting the air volume preferred by the user via the remote controller 50.

[0098] (3-7) The first temperature Ta is set within the range of 18°C ​​to 28°C.

[0099] (4) Variations (4-1) First Modification In the above embodiment, low-load heating operation is defined as "operation in which a substitute value indicating the load during heating operation satisfies a specified condition. In this embodiment, the substitute value is the difference ΔT obtained by subtracting the measured value from the set value of the indoor temperature, and the specified condition is that the difference ΔT is 0°C or less."

[0100] However, the present invention is not limited to this, and the substitute value may be the operating frequency fo of the compressor, and the predetermined condition may be the operating frequency fo being 20 Hz or less.

[0101] In the air conditioning device 1 of the first variant, if the operating frequency fo of the compressor 21 is 20 Hz or less, the indoor temperature is stable, and with conventional indoor fan airflow control, it is not possible to obtain an airflow volume sufficient to stir the indoor air. However, by increasing the airflow of the indoor fan 34 in line with the rise in the indoor temperature, the indoor air is stirred and the occurrence of warm air pockets at the top of the room can be suppressed.

[0102] (4-2) Second Modification In the above embodiment, the detection value of the indoor temperature sensor 61 is used as a substitute for the indoor temperature, but this is not limited to this. A radiation sensor may be provided instead of the indoor temperature sensor 61, and the detection value of the radiation sensor may be used as a substitute for the indoor temperature.

[0103] (4-3) In the above embodiment, the detection value of the heat exchanger temperature sensor 62 is substituted for the temperature of the indoor heat exchanger 32, but this is not limited to this. A third temperature sensor may be arranged in the outlet flow path 318 leading from the indoor heat exchanger 32 to the outlet 311, and the control unit 40 may estimate the temperature of the indoor heat exchanger 32 from the detection value of the third temperature sensor.

[0104] Although the embodiments of the present disclosure have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the present disclosure described in the claims. [Explanation of symbols]

[0105] 1. Air conditioning equipment 32 Indoor heat exchanger 34 Indoor fan 40 Control section 41 Outdoor control unit (control unit) 42 Indoor control unit (control unit) 50 Remote controller (air volume setting means) 61 Indoor temperature sensor (first temperature measurement unit) 62 Heat exchanger temperature sensor (second temperature measurement part) 311 Air outlet 318 Air passage (air passage) 321 1st heat exchange section (indoor heat exchanger) 322 Second heat exchange section (indoor heat exchanger) [Prior art documents] [Patent documents]

[0106] [Patent Document 1] Jpn. Jpn. Published No. 53-1632

Claims

1. An air-conditioning apparatus for heating a room by exchanging heat in an indoor heat exchanger (32) between a high-temperature, high-pressure refrigerant discharged from a compressor (21) and air taken in from an intake port by the rotation of an indoor fan (34), and sending out the air heated in the indoor heat exchanger (32) from an outlet port, A first temperature measuring unit that measures a temperature (Tr) inside the room; A second temperature measuring unit that measures a temperature (Th) of the indoor heat exchanger (32); A control unit (40) for controlling the rotation speed of the indoor fan (34); Equipped with When a low-load heating operation is performed in which a substitute value indicating a load during the heating operation satisfies a predetermined condition, if the temperature (Th) of the indoor heat exchanger (32) is equal to or lower than a first temperature (Ta), When the indoor temperature (Tr) is equal to or lower than a second temperature (Tb), the indoor fan (34) is rotated at a first rotation speed (fa); When the indoor temperature (Tr) exceeds a second temperature (Tb), the indoor fan (34) is rotated at a second rotation speed (fb) which is higher than the first rotation speed (fa). Air conditioning unit (1).

2. The substitute value is the difference (ΔT) between the set value and the measured value of the indoor temperature, The predetermined condition is that the difference (ΔT) is 0° C. or less. An air conditioning device (1) as claimed in claim 1.

3. The substitute value is an operating frequency (f0) of the compressor (21), The predetermined condition is that the operating frequency (fo) is 20 Hz or less. An air conditioning device (1) as claimed in claim 1.

4. The first temperature measurement unit has a first temperature sensor (61) that detects the temperature of the air taken into the air inlet, and uses a detection value of the first temperature sensor (61) as a substitute for the temperature (Tr) in the room. An air conditioner (1) according to any one of claims 1 to 3.

5. The first temperature measurement unit has a radiation sensor that detects a radiation temperature in the room, and a detection value of the radiation sensor is used as a substitute for the temperature in the room. An air conditioner (1) according to any one of claims 1 to 3.

6. The second temperature measurement unit has a second temperature sensor (62) attached to the indoor heat exchanger (32), The control unit (40) substitutes the detection value of the second temperature sensor (62) for the temperature of the indoor heat exchanger (32). An air conditioner (1) according to any one of the preceding claims.

7. The second temperature measurement unit has a third temperature sensor arranged in an air passage from the indoor heat exchanger (32) to the air outlet, and estimates the temperature of the indoor heat exchanger (32) from a detection value of the third temperature sensor. An air conditioner (1) according to any one of the preceding claims.

8. The lower limit value of the first rotation speed (fa) is set according to the temperature (Th) of the indoor heat exchanger (32), the lower limit value of the first rotation speed (fa) when the indoor temperature (Tr) is higher than the second temperature (Tb) is higher than the lower limit value of the first rotation speed (fa) when the indoor temperature (Tr) is equal to or lower than the second temperature (Tb); An air conditioner (1) according to any one of the preceding claims.

9. The indoor fan (34) further includes an air volume setting means (50) for setting the air volume of the indoor fan (34), When the indoor temperature (Tr) is higher than the second temperature (Tb), the control unit (40) rotates the indoor fan (34) at a rotation speed corresponding to the air volume set by the air volume setting means (50). An air conditioner (1) according to any one of the preceding claims.

10. The first temperature (Ta) is set within a range of 18°C ​​to 35°C; An air conditioner (1) according to any one of the preceding claims.

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