Air conditioner indoor unit

Abstract

To suppress the occurrence of "warm air reservoir" in an upper part of a room, while suppressing feeling of draft to residents.SOLUTION: In an indoor unit of an air conditioner, since a control unit performs a first control, which is a control of supercooling a refrigerant flowing through a first heat exchange unit 321, during a low-load heating operation, an air passage guides a first airflow St1 passing through the first heat exchange unit to the upper part of a blowout port 311, and guides a second airflow St2 passing through a second heat exchanging unit 322 downward from the first airflow St1.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] The indoor unit of the air conditioner according to a first aspect is an indoor unit of the air conditioner that heats the room, and includes an indoor heat exchanger, an indoor fan, a casing, and a control unit. The indoor heat exchanger has a first heat exchange unit and a second heat exchange unit, and the number of paths into which the high-temperature gas refrigerant flows during heating operation is set to be greater in the second heat exchange unit than in the first heat exchange unit. The indoor fan is disposed in a space sandwiched between the first heat exchange unit and the second heat exchange unit, and generates an air flow including a first air flow passing through the first heat exchange unit and a second air flow passing through the second heat exchange unit. The casing houses the indoor heat exchanger and the indoor fan, and has an air outlet and an air passage. The control unit performs a first control that is a control for putting the refrigerant flowing through the first heat exchange unit into a supercooled state during heating operation. The first air flow is guided to an upper part of the air outlet by the air passage, and the second air flow is guided below the first air flow.

[0006] In the indoor unit of this air conditioner, the air is blown out from the outlet in two layers: a first air current with a lower temperature in the upper layer and a second air current with a higher temperature in the lower layer, so that the first air current with a lower temperature flows upwards away from the occupants and stirs up the warm air pocket near the ceiling, while the second air current with a higher temperature flows toward the occupants.

[0007] An indoor unit of an air conditioner of a second aspect is an indoor unit of the air conditioner of the first aspect, in which the control unit executes a first control during low-load operation when a substitute value indicating the load during heating operation satisfies a predetermined condition.

[0008] Generally, when air blows on an occupant during low load operation, the occupant feels a sense of cool air. However, when the first control is executed, the first airflow, which has a low temperature, is directed upward so as not to blow on the occupant, and the second airflow, which has a higher temperature than the first airflow, is directed toward the occupant, so that the occupant is prevented from feeling a sense of cool air.

[0009] An indoor unit of an air conditioner according to a third aspect is the indoor unit of the air conditioner according to the second aspect, further comprising a first temperature measurement unit that measures an indoor temperature Tr. The substitute value is the difference ΔTrs between the set value and the measured indoor temperature. The predetermined condition is that the difference ΔTrs is equal to or less than a first predetermined value.

[0010] An indoor unit of an air conditioner according to a fourth aspect is the indoor unit of the air conditioner according to any one of the first aspect to the third aspect, wherein the second airflow is guided between the center of the air outlet and the lower end of the air outlet.

[0011] An indoor unit of an air conditioner according to a fifth aspect is the indoor unit of the air conditioner according to the first aspect, further comprising a first temperature measuring unit and a second temperature measuring unit. The first temperature measuring unit measures the temperature inside the room. The second temperature measuring unit measures the temperature of the indoor heat exchanger. The control unit executes the first control when a difference ΔThr between the temperature of the indoor heat exchanger and the temperature inside the room is equal to or smaller than a second predetermined value.

[0012] An indoor unit of an air conditioning apparatus of a sixth aspect is an indoor unit of an air conditioning apparatus of any one of the second aspect to the fifth aspect, and during low load operation, the minimum air volume of the indoor fan when the first control is executed is greater than the minimum air volume of the indoor fan when the first control is not executed.

[0013] In the indoor unit of this air conditioner, the air volume can be made greater than the minimum air volume during low-load operation, so the pool of warm air near the ceiling is more likely to be stirred by the first airflow blown upward.

[0014] An indoor unit of an air conditioner according to a seventh aspect is the indoor unit of the air conditioner according to any one of the first aspect to the sixth aspect, further comprising an air direction adjustment louver. The air direction adjustment louver adjusts the direction of air blown out from the air outlet. The control unit controls the air direction adjustment louver so that the first airflow is blown out higher than the second airflow.

[0015] In this indoor unit of the air conditioner, the airflow direction adjustment blade increases the directionality of the blown air, making it easy to blow the low-temperature first airflow upward and the high-temperature second airflow downward.

[0016] An indoor unit of an air conditioner according to an eighth aspect is the indoor unit of the air conditioner according to the seventh aspect, wherein the air direction adjustment blade includes a first air direction adjustment blade and a second air direction adjustment blade that swing up and down to adjust the vertical direction of the blown air. The rotation axis around which the first air direction adjustment blade swings is provided on the upper end side of the air outlet. The rotation axis around which the second air direction adjustment blade swings is provided on the lower end side of the air outlet. The first air direction adjustment blade adjusts the air direction of the first airflow, and the second air direction adjustment blade adjusts the air direction of the second airflow.

[0017] In the indoor unit of this air conditioner, because airflow has the property of flowing along a surface, the first airflow can be directed upward from the air outlet along the first airflow direction adjustment blade whose rotation axis is provided on the upper end side of the air outlet, and the second airflow can be directed downward from the air outlet along the second airflow direction adjustment blade whose rotation axis is provided on the lower end side of the air outlet. [Brief description of the drawings]

[0018] [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] FIG. 2 is an explanatory diagram illustrating an example of a refrigerant path of an indoor heat exchanger. [Diagram 5] 4 is a flowchart of a first control. [Figure 6] 10 is a side view showing the attitudes of the first airflow direction adjustment blade and the second airflow direction adjustment blade during a first control. FIG. [Figure 7] 13 is a flowchart of a first control according to a first modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] (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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] (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.

[0024] (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.

[0025] (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.

[0026] 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.

[0027] 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.

[0028] (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.

[0029] (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.

[0030] 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.

[0031] (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.

[0032] (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.

[0033] (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.

[0034] 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 .

[0035] (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 .

[0036] (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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] (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.

[0042] 4 is an explanatory diagram showing an example of the refrigerant path of the indoor heat exchanger. In FIG. 4, during heating operation, the high-temperature gas refrigerant that has entered the flow divider Di is divided into four and flows into the second heat exchange section 322.

[0043] Therefore, in the indoor heat exchanger 32, all of the inlets of the refrigerant paths into which the high-temperature gas refrigerant flows during heating operation are provided in the second heat exchange section 322. However, this is not limited thereto, and it is sufficient that the number of inlets of the refrigerant paths into which the high-temperature gas refrigerant flows during heating operation is set to be greater in the second heat exchange section 322 than in the first heat exchange section 321.

[0044] (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.

[0045] (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.

[0046] 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.

[0047] (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.

[0048] The microcomputer 42a performs various calculations in the indoor unit 3. In addition, the memory 42b stores various data.

[0049] 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.

[0050] (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).

[0051] The heat exchanger temperature sensor 62 is attached approximately in the center of the refrigerant path of the indoor heat exchanger 32 , and measures the temperature of the refrigerant flowing through the indoor heat exchanger 32 .

[0052] (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.

[0053] 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.

[0054] (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.

[0055] (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.

[0056] 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.

[0057] 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.

[0058] (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.

[0059] 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.

[0060] (2-2-1) Thermo off and thermo on during heating operation Here, the thermo-off and thermo-on during heating operation will be described.

[0061] Thermo-off is a function that automatically stops the heating operation temporarily during heating operation according to the set temperature. Specifically, when the indoor temperature Tr exceeds the set temperature Ts and the absolute value of the difference ΔT between the set temperature Ts and the indoor temperature Tr becomes larger than a predetermined value (e.g., 2 deg), the control unit 40 temporarily stops the compressor 21. At this time, the function of the indoor heat exchanger 32 as a condenser is also temporarily stopped.

[0062] 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 between the set temperature Ts and the indoor temperature Tr becomes greater than a predetermined value (e.g., 0.5 deg.). At this time, the indoor heat exchanger 32 resumes its function as a condenser.

[0063] (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, the occupant may feel cold when exposed to the air blown out from the air outlet 311, which is called a draft feeling.

[0064] Here, "when the temperature of the refrigerant flowing through the indoor heat exchanger 32 drops" refers to, for example, when the air conditioner 1 is performing low-load heating operation.

[0065] 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 between the set value and the measured value of the indoor temperature, and the specified condition is that the difference ΔT is less than or equal to a specified value before the thermostat is turned off.

[0066] 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 drop to around 25°C to 30°C or even lower, and the temperature of the blown air will drop to close to room temperature, so that the occupants will feel cold when they are exposed to the blown air.

[0067] 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.

[0068] (2-2-3) Suppression of cold air flow by the first control during low-load heating operation However, when the above-mentioned 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.

[0069] 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.

[0070] Therefore, in this embodiment, inlets for high-temperature gas refrigerant of multiple refrigerant paths in the indoor heat exchanger 32 are provided in advance in the second heat exchange section 322, and during low-load heating operation, the refrigerant is condensed in the second heat exchange section 322 to make the refrigerant flowing through the first heat exchange section 321 into a supercooled state. Here, this control is referred to as the "first control."

[0071] In this embodiment, the first control can suppress the "feeling of draft (feeling of cold air)" and the "occurrence of warm air pooling" without reducing the air volume of the indoor fan 34, even during low-load heating operation.

[0072] 5 is a flowchart of the first control. Hereinafter, the operation of the first control will be described with reference to FIG.

[0073] (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.

[0074] (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.

[0075] (Step S3) Next, in step S3, the control unit 40 determines whether the absolute value of the difference ΔT between the set temperature Ts and the room temperature Tr is equal to or less than a predetermined value d. If the absolute value of the difference ΔT is equal to or less than the predetermined value d, it determines that the heating operation is a low-load heating operation, and proceeds to step S4.

[0076] (Step S4) Next, in step S4, the control unit 40 controls at least one of the frequency of the compressor 21 and the opening degree of the outdoor expansion valve 24 to make the refrigerant flowing through the first heat exchange unit 321 into a subcooled state. At this time, the air volume of the indoor fan 34 is not changed, or is adjusted to a larger air volume than when the cold air suppression function is operating.

[0077] (Step S5) Then, in step S5, the control unit 40 controls the attitude of the first airflow direction adjustment blade 361 to face upward, and controls the attitude of the second airflow direction adjustment blade 362 to face downward.

[0078] FIG. 6 is a side view showing the attitudes of the first airflow direction adjustment blade 361 and the second airflow direction adjustment blade 362 during the first control.

[0079] 6, the first airflow direction adjustment louver 361 is controlled so that its front end faces upward from the horizontal. As a result, the first airflow St1 after passing through the first heat exchanger 321 flows along the lower surface of the first airflow direction adjustment louver 361 and heads toward the upper space inside the room.

[0080] On the other hand, the second airflow direction adjustment louver 362 is controlled so that its front end faces downward, or the tangent line at the front end faces downward. As a result, the second airflow St2 after passing through the second heat exchanger 322 flows along the front surface of the second airflow direction adjustment louver 362 and heads toward the lower space in the room.

[0081] (Actions and Effects of the First Control) 4, the airflow that has passed through the first heat exchange section 321 (hereinafter referred to as the first airflow St1) passes between the upper end and the center of the air outlet 311 and is blown out. On the other hand, the airflow that has passed through the second heat exchange section 322 (hereinafter referred to as the second airflow St2) passes between the lower end and the center of the air outlet 311 and is blown out.

[0082] This is because the indoor fan 34 is disposed in the space formed between the first heat exchange section 321, which is located in front of the indoor fan 34, and the second heat exchange section 322, which is located behind the indoor fan 34.

[0083] Then, when the control unit 40 controls at least one of the frequency of the compressor 21 or the opening of the outdoor expansion valve 24 to bring the refrigerant flowing through the first heat exchange unit 321 into a supercooled state, the second airflow St2 passing through the second heat exchange unit 322 is heated by heat exchange with the high-temperature gas refrigerant flowing through the second heat exchange unit 322. On the other hand, the first airflow St1 passing through the first heat exchange unit 321 is hardly heated because the refrigerant flowing through the first heat exchange unit 321 is in a supercooled state.

[0084] Therefore, the first airflow St1 having a temperature close to the room temperature Tr is blown upward above the center of the air outlet 311, and the heated second airflow St2 is blown downward below the center of the air outlet 311. Therefore, the occupants do not feel cold because they are hit by the heated second airflow St2, and the unheated first airflow St1 heads upward and does not hit the occupants.

[0085] As a result, even during low-load heating operation, there is no need to reduce the airflow rate of the indoor fan 34, and the first airflow St1 blown upward mixes the air in the room, which also contributes to preventing warm air from accumulating.

[0086] (3) Features (3-1) In the indoor unit 3 of the air conditioner 1, the control unit 40 performs the first control, which is a control for making the refrigerant flowing through the first heat exchanger 321 into a supercooled state during low-load heating operation, so that the first airflow St1 passing through the first heat exchanger 321 is guided to the upper part of the air outlet 311 by the air outlet flow passage 318, and the second airflow St2 passing through the second heat exchanger 322 is guided below the first airflow St1. As a result, the air is blown out from the air outlet 311 in two layers, the upper layer first airflow St1 with a low temperature and the lower layer second airflow St2 with a higher temperature than the first airflow St1. The lower temperature first airflow St1 heads upwards so as not to hit the occupants, stirring up the warm air pool near the ceiling. On the other hand, the second airflow St2 with a higher temperature than the first airflow St1 heads toward the occupants, so that the occupants are prevented from feeling a cold breeze.

[0087] (3-2) The condition for low-load heating operation under which the first control is executed is that the difference ΔTrs between the set value and the measured value of the room temperature is equal to or smaller than a predetermined value (for example, 2 deg).

[0088] (3-3) The second airflow St2 is guided to between the center of the air outlet 311 and the lower end of the air outlet 311.

[0089] (3-4) During low-load heating operation, the minimum air volume of the indoor fan 34 when the first control is executed is greater than the minimum air volume of the indoor fan 34 when the first control is not executed. Therefore, during the first control, the warm air pool near the ceiling is easily stirred by the first airflow St1 blown upward.

[0090] (3-5) In the indoor unit 3 of the air conditioning apparatus 1, the control unit 40 can direct the first airflow St1 upward from the air outlet 311 along a first airflow direction adjustment blade 361 whose rotation axis is provided on the upper end side of the air outlet 311. In addition, the control unit 40 can direct the second airflow St2 downward from the air outlet 311 along a second airflow direction adjustment blade 362 whose rotation axis is provided on the lower end side of the air outlet 311.

[0091] (4) Variations (4-1) First Modification The control unit 40 may execute the first control when the difference ΔThr between the temperature of the indoor heat exchanger 32 and the room temperature is equal to or smaller than a predetermined value (for example, 5 deg).

[0092] 7 is a flowchart of the first control according to the first modified example. Hereinafter, the operation of the first control will be described with reference to FIG.

[0093] (Step S11) In step S11, the control unit 40 measures the room temperature Tr. In the first modified example, as in the present 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.

[0094] (Step S12) Next, in step S12, the control unit 40 measures the temperature Th of the indoor heat exchanger 32. In the first modified example, the temperature Th of the indoor heat exchanger 32 is substituted for the detection value of the heat exchanger temperature sensor 62 attached to approximately the center of the refrigerant path of the indoor heat exchanger 32.

[0095] (Step S13) Next, in step S13, the control unit 40 determines whether the difference ΔThr between the temperature Th of the indoor heat exchanger 32 and the indoor temperature Tr is equal to or smaller than a predetermined value e. If the difference ΔT is equal to or smaller than the predetermined value e, it determines that the heating operation is low-load heating operation, and proceeds to step S14.

[0096] (Step S14) Next, in step S14, the control unit 40 controls the opening degree of the outdoor expansion valve 24 to make the refrigerant flowing through the first heat exchange unit 321 into a subcooled state. At this time, the air volume of the indoor fan 34 is not changed, or is adjusted to a larger air volume than when the cold air suppression function is operating.

[0097] (Step S15) Then, in step S15, the control unit 40 controls the attitude of the first airflow direction adjustment blade 361 to face upward, and controls the attitude of the second airflow direction adjustment blade 362 to face downward.

[0098] As a result, the first airflow St1 passing through the first heat exchanger 321 is guided to the upper part of the air outlet 311, and the second airflow St2 passing through the second heat exchanger 322 is guided below the first airflow St1. As a result, the air is blown out of the air outlet in two layers, the upper layer first airflow St1 having a low temperature, and the lower layer second airflow St2 having a higher temperature than the first airflow St1. The lower temperature first airflow St1 heads upwards out of the way of the occupants, stirring up the warm air pool near the ceiling. On the other hand, the second airflow St2 having a higher temperature than the first airflow St1 heads toward the occupants, so the occupants are prevented from feeling a cold breeze.

[0099] (4-2) Second Modification In the above embodiment and the first modified example, the attitude of the second airflow direction adjustment louver 362 during the first control is fixed, but it may be swung.

[0100] (5)Other (5-1) In the above embodiment and the first modified example, the first control is executed after it is determined that the heating operation is a low-load heating operation, but it does not necessarily have to be a low-load heating operation and may be executed during normal heating operation.

[0101] (5-2) In the above embodiment and the first modified example, during the first control, the first airflow direction adjustment lobe 361 directs the first airflow St1 after passing through the first heat exchange section 321 toward the upper space in the room, and the second airflow direction adjustment lobe 362 directs the second airflow St2 after passing through the second heat exchange section 322 toward the lower space in the room.

[0102] However, both the first airflow direction adjustment blade 361 and the second airflow direction adjustment blade 362 are not necessarily required.

[0103] The first airflow St1 that has passed through the first heat exchange section 321 and the second airflow St2 that has passed through the second heat exchange section 322 are blown out from the airflow outlet 311 while maintaining the relationship that the first airflow St1 is above and the second airflow St2 is below until they reach the airflow outlet 311, so that even if there is only one airflow direction adjustment blade in the center of the airflow outlet 311, by blowing upward, the first airflow St1 can be blown out in a concentrated manner toward the ceiling so that it is less likely to hit people. Also, by blowing downward, the second airflow St2 can be blown out in a concentrated manner toward the floor so that it is more likely to hit people.

[0104] Therefore, during the first control, both the first airflow direction adjustment blade 361 and the second airflow direction adjustment blade 362 do not have to be used.

[0105] 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]

[0106] 1. Air conditioning equipment 3 Indoor unit 31 Casing 32 Indoor heat exchanger 34 Indoor fan 36 Wind direction adjustment blade 40 Control section 41 Outdoor control unit (control unit) 42 Indoor control unit (control unit) 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 322 Second heat exchange section 361 First wind direction adjustment blade 362 Second wind direction adjustment blade [Prior art documents] [Patent documents]

[0107] [Patent Document 1] Jpn. Jpn. Published No. 53-1632

Claims

1. An indoor unit of an air conditioner that heats a room, an indoor heat exchanger (32) having a first heat exchange section (321) and a second heat exchange section (322), the number of paths into which a high-temperature gas refrigerant flows during heating operation being set to be greater in the second heat exchange section (322) than in the first heat exchange section (321); an indoor fan (34) that is disposed in a space between the first heat exchange section (321) and the second heat exchange section (322) and generates an air flow including a first air flow passing through the first heat exchange section (321) and a second air flow passing through the second heat exchange section (322); a casing (31) that houses the indoor heat exchanger (32) and the indoor fan (34) and has an air outlet (311) and an air passage (318); A control unit (40) that performs a first control, which is a control for making the refrigerant flowing through the first heat exchange unit (321) into a supercooled state during a heating operation; Equipped with The first airflow is guided to an upper portion of the air outlet (311) and the second airflow is guided below the first airflow, The control unit (40) executes the first control during low-load operation in which a substitute value indicating a load during a heating operation satisfies a predetermined condition, During the low load operation, the minimum air volume of the indoor fan (34) when the first control is executed is greater than the minimum air volume of the indoor fan (34) when the first control is not executed. An indoor unit (3) of an air conditioner.

2. The vehicle further includes a first temperature measuring unit (61) for measuring a temperature (Tr) inside the vehicle; The substitute value is the difference (ΔTrs) between the set value and the measured value of the indoor temperature, The predetermined condition is that the difference (ΔTrs) is equal to or smaller than a first predetermined value. An indoor unit (3) for an air conditioner according to claim 1.

3. The second air flow is guided between the center of the air outlet (311) and the lower end of the air outlet (311). An indoor unit (3) for an air conditioner according to claim 1 or 2.

4. A first temperature measuring unit (61) for measuring a temperature (Tr) inside the room; A second temperature measuring unit (62) that measures a temperature (Th) of the indoor heat exchanger; Further equipped with The control unit (40) executes the first control when a difference (ΔThr) between the temperature of the indoor heat exchanger (32) and the temperature inside the room is equal to or smaller than a second predetermined value. An indoor unit (3) for an air conditioner according to claim 1.

5. The fan further includes a wind direction adjustment blade (36) for adjusting the direction of air blown out from the air outlet (311), The control unit (40) controls the airflow direction adjustment blade (36) so that the first airflow is blown upward relative to the second airflow. An indoor unit (3) for an air conditioner according to any one of claims 1 to 4.

6. The airflow direction adjustment blade (36) includes a first airflow direction adjustment blade (361) and a second airflow direction adjustment blade (362) that swing up and down to adjust the vertical direction of the blown air, A rotation axis when the first airflow direction adjustment blade (361) swings is provided on the upper end side of the air outlet (311), and a rotation axis when the second airflow direction adjustment blade (362) swings is provided on the lower end side of the air outlet (311), The first airflow direction adjusting blade (361) adjusts the airflow direction of the first airflow, and the second airflow direction adjusting blade (362) adjusts the airflow direction of the second airflow. An indoor unit (3) for an air conditioner according to claim 5.

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