JP7395056B2 - Air conditioner and control method - Google Patents

Description

The present disclosure relates to an air conditioner and a control method.

In a multi-air conditioner in which multiple indoor units are connected to one outdoor unit, when the cooling operation of at least one indoor unit is stopped, the expansion valve that controls the flow of refrigerant from the outdoor unit If the indoor unit is not fully closed for some reason, refrigerant may flow from the outdoor unit into the indoor unit, causing dew condensation on the indoor unit that has been cooled below the dew point. In order to prevent this condensation from occurring, a technology has been disclosed that determines that refrigerant has flowed into the stopped indoor unit and initializes the expansion valve if the temperature of the heat exchanger of the indoor unit remains below a predetermined temperature. (For example, Patent Document 1).

Japanese Patent Application Publication No. 2003-114043

However, the expansion valve may not be fully closed due to foreign matter such as metal powder (for example, copper powder) being caught in the expansion valve. In such a case, even if the expansion valve is initialized as in the technology disclosed in Patent Document 1, the expansion valve will not always close, so the refrigerant will continue to flow into the indoor unit and condensation will occur. Sometimes it happens.

The present disclosure has been made in view of the above-mentioned circumstances, and provides an air conditioner and control system that suppresses the occurrence of dew condensation in an indoor unit in an air conditioner in which a plurality of indoor units are connected to one outdoor unit. One of the purposes is to provide a method.

According to the present disclosure, an air conditioner including one outdoor unit and a plurality of indoor units to which refrigerant pipes through which refrigerant sent out from the outdoor unit flows is connected, the air conditioner has a flow rate of refrigerant flowing through the refrigerant pipes. an indoor heat exchanger connected to the refrigerant piping via an expansion valve that controls the temperature of the indoor heat exchanger; a temperature sensor that detects the temperature of the indoor heat exchanger; and an indoor heat exchanger that takes air into the indoor unit and exchanges heat with the indoor heat exchanger. an indoor unit fan for blowing out the air, and in response to the shutdown of the indoor unit, the indoor unit fan is stopped and the expansion valve is closed; a control unit that rotates the indoor unit fan when the temperature detected by the temperature sensor is below a predetermined temperature , the control unit configured to rotate the indoor unit fan when the temperature detected by the temperature sensor is When the temperature reaches a predetermined temperature or higher, the indoor unit fan is stopped, and when the indoor unit fan is rotated and stopped a predetermined number of times or more while the indoor unit is stopped, notification information is output. do .

Furthermore, an air conditioner according to the present disclosure includes one outdoor unit and a plurality of indoor units each connected to a refrigerant pipe through which a refrigerant sent out from the outdoor unit flows, wherein the refrigerant pipe is connected to the indoor unit. an indoor heat exchanger connected to the refrigerant piping via an expansion valve that controls the flow rate of the refrigerant; a temperature sensor that detects the temperature of the indoor heat exchanger; and an indoor heat exchanger that takes air into the indoor unit. The control method in the air conditioner in which each of the indoor units includes an indoor unit fan for blowing out the heat-exchanged air includes a step in which the temperature sensor detects the temperature of the indoor heat exchanger; The unit stops the indoor unit fan and closes the expansion valve in response to the shutdown of the indoor unit, and causes the temperature detected by the temperature sensor to reach a predetermined temperature during the shutdown of the indoor unit. The step of rotating the indoor unit fan in the following cases; The method includes a step of stopping a fan, and a step of outputting notification information when the control unit repeats control of rotation and stop of the indoor unit fan a predetermined number of times or more while the indoor unit is stopped.

According to the present disclosure, in an air conditioner in which a plurality of indoor units are connected to one outdoor unit, it is possible to suppress the occurrence of dew condensation in the indoor units.

FIG. 1 is a block diagram showing a schematic configuration example of an air conditioner according to a first embodiment. FIG. 3 is an external view showing an example of the wall-mounted indoor unit when the operation is stopped according to the first embodiment. FIG. 2 is an external view showing an example of the wall-mounted indoor unit in operation according to the first embodiment. FIG. 3 is a diagram showing an example of airflow in the wall-mounted indoor unit during operation according to the first embodiment. FIG. 3 is a diagram showing an example of the blowing direction and airflow when rotating the indoor unit fan during shutdown according to the first embodiment. 7 is a flowchart illustrating a first example of an operation for starting dew condensation prevention processing during shutdown according to the first embodiment. 7 is a flowchart showing a second example of an operation for starting dew condensation prevention processing during shutdown according to the first embodiment. 5 is a flowchart showing a first example of an operation for stopping dew condensation prevention processing during an operation stop according to the first embodiment. 7 is a flowchart illustrating a second example of an operation for stopping dew condensation prevention processing during an operation stop according to the first embodiment. 5 is a flowchart illustrating an example of operation of notification processing according to the first embodiment. FIG. 7 is an external view showing an example of a ceiling-embedded indoor unit according to a second embodiment. FIG. 7 is a diagram illustrating an example of a ceiling-embedded indoor unit when the operation is stopped according to the second embodiment. FIG. 7 is a diagram showing the blowing direction of the ceiling-mounted indoor unit during operation according to the second embodiment. FIG. 7 is a diagram showing the blowing direction when rotating the indoor unit fan during shutdown according to the second embodiment.

Embodiments will be described below with reference to the drawings.
<First embodiment>
First, a first embodiment will be described.
[Air conditioner configuration]
FIG. 1 is a block diagram showing a schematic configuration example of an air conditioner according to this embodiment. The illustrated air conditioner 1 is a multi-type air conditioner in which a plurality of indoor units 20 are connected to one outdoor unit 10. Here, an example is shown in which three indoor units 20, an indoor unit 20A, an indoor unit 20B, and an indoor unit 20C, are connected to the outdoor unit 10. Note that the number of indoor units 20 connected to the outdoor unit 10 can be any number. Since the basic configurations of the indoor unit 20A, the indoor unit 20B, and the indoor unit 20C are the same, they are simply referred to as the indoor unit 20 unless they are particularly distinguished. The air conditioner 1 has a function of cooling and heating a space in which an indoor unit 20 is installed. Note that the air conditioner 1 may be a device having at least a cooling function.

The remote controller 30 is a terminal device that performs wireless communication such as infrared communication with the indoor unit 20. The remote controller 30 receives user operations for starting or stopping the operation of the indoor unit 20, setting the cooling temperature or heating temperature, setting the air volume, setting the air direction, etc., and transmits an operation signal to the indoor unit 20 based on the operation. Usually, one remote control 30 is provided for one indoor unit 20. Here, a remote controller 30A, a remote controller 30B, and a remote controller 30C are provided for each of the indoor units 20A, 20B, and 20C.

The outdoor unit 10 and the indoor unit 20 are connected to each other by a liquid pipe 11 and a gas pipe 12. The liquid pipe 11 and the gas pipe 12 are refrigerant pipes through which refrigerant flows. The outdoor unit 10 includes a compressor 13, an outdoor heat exchanger 14, a four-way valve 15, an outdoor expansion valve 16, an outdoor unit fan 17, an outside temperature sensor 18, and an outdoor unit control section 19. The four-way valve 15 is connected in series between the discharge side and the suction side of the compressor 13. The outdoor heat exchanger 14 is connected at one end to an outdoor expansion valve 16 (electronic expansion valve) via a liquid pipe 11 and at the other end to a four-way valve 15 via a gas pipe 12. The liquid pipe 11 is piped to the outside of the outdoor unit 10 via an outdoor expansion valve 16, and is further connected to the indoor unit 20 via a closing valve 11V. The gas pipe 12 is piped to the outside of the outdoor unit 10 via a four-way valve 15, and is further connected to the indoor unit 20 via a closing valve 12V.

The outdoor unit fan 17 is a blower that takes air (outside air) into the outdoor unit 10 and blows out air that has been heat exchanged with the outdoor heat exchanger 14 from the outdoor unit 10. The outside temperature sensor 18 is a temperature sensor for detecting outside temperature. The outdoor unit control unit 19 controls each part of the outdoor unit 10. For example, the outdoor unit control unit 19 switches the flow path of the four-way valve 15 based on operation information such as starting or stopping cooling or heating, setting information such as air volume, temperature detected by the outside temperature sensor 18, etc. , the operation of the compressor 13, the rotation of the outdoor unit fan 17, the opening/closing of the outdoor expansion valve 16, and the degree of opening (refrigerant flow rate). The outdoor unit control section 19 acquires the above-mentioned operating information and setting information from the indoor unit 20.

The indoor unit 20 includes a receiving section 23, an indoor heat exchanger 24, a heat exchanger temperature sensor 25, an indoor expansion valve 26, an indoor unit fan 27, a room temperature sensor 28, and an indoor unit control section 29. The receiving unit 23 receives an operation signal (for example, an infrared signal) transmitted from the remote controller 30 and outputs the received operation signal to the indoor unit control unit 29. One end of the indoor heat exchanger 24 is connected to the liquid pipe 11 via the indoor expansion valve 26, and the other end is connected to the gas pipe 12 piped from the outdoor unit 10. The indoor expansion valve 26 is an electronic expansion valve inserted into the liquid pipe 11 piped from the outdoor unit 10, and is used to control the flow rate of the refrigerant flowing through the liquid pipe 11. The heat exchanger temperature sensor 25 is a temperature sensor provided on the surface of the indoor heat exchanger 24 (for example, the surface of the heat exchanger heat transfer tube). This heat exchanger temperature sensor 25 is used to detect the temperature of the refrigerant flowing into the indoor unit 20.

The indoor unit fan 27 is a blower that takes indoor air into the indoor unit 20 and blows out the air that has been heat exchanged with the indoor heat exchanger 24 from the indoor unit 20 into the room. Room temperature sensor 28 is a temperature sensor for detecting the room temperature where indoor unit 20 is installed.

The indoor unit control section 29 acquires an operation signal from the remote control 30 via the reception section 23 . In addition, the indoor unit control section 29 acquires the temperature detected by the room temperature sensor 28 and the temperature detected by the heat exchanger temperature sensor 25. The indoor unit control section 29 controls each section of the indoor unit 20 based on the operation signal obtained from the remote controller 30. For example, when the indoor unit control unit 29 acquires an operation signal indicating operation information for starting cooling or heating operation from the remote controller 30, it controls the operation of the indoor unit 20 to start, and transmits the operation information to the outdoor unit 10. Send. Each indoor unit 20 and the outdoor unit 10 are connected by a communication line 21 for mutually transmitting and receiving information. The indoor unit control section 29 can also acquire information on the outdoor unit 10 side from the outdoor unit control section 19 via the communication line 21. The information on the outdoor unit 10 side includes information such as the temperature detected by the outside air temperature sensor 18.

When starting the operation of the indoor unit 20, the indoor unit control section 29 rotates the indoor unit fan 27 and controls the indoor expansion valve 26 to open. While the indoor unit is in operation, the indoor unit control unit 29 controls the indoor unit fan 27 based on the air volume setting information acquired from the remote controller 30, the temperature detected by the room temperature sensor 28, the temperature detected by the heat exchanger temperature sensor 25, etc. , the opening/closing of the indoor expansion valve 26, the opening degree (refrigerant flow rate), etc.

Further, when the indoor unit control unit 29 acquires an operation signal indicating operation information for stopping cooling or heating operation from the remote controller 30, it performs control to stop the operation of the indoor unit 20, and transmits the operation information to the outdoor unit 10. Send. When stopping the operation of the indoor unit 20, the indoor unit control section 29 stops the indoor unit fan 27 (stops rotation) and controls the indoor expansion valve 26 to be in a closed state.

Here, the refrigeration cycle of the air conditioner 1 will be explained. The outdoor unit 10 switches between heating operation and cooling operation by switching the flow path of the four-way valve 15 to switch the circulation direction of the refrigerant. The flow of refrigerant indicated by the arrow in FIG. 1 indicates the flow of refrigerant during cooling operation.

In the case of cooling operation, the refrigerant compressed by the compressor 13 flows into the outdoor heat exchanger 14 through the four-way valve 15 . The refrigerant in the outdoor heat exchanger 14 exchanges heat with the surrounding air. The refrigerant that has become liquid due to heat exchange flows into the liquid pipe 11, passes through the outdoor expansion valve 16 and the closing valve 11V, and flows into the indoor heat exchanger 24. The refrigerant in the indoor heat exchanger 24 exchanges heat with the surrounding air to cool the surrounding air. The refrigerant, which has become a gas due to heat exchange, returns to the compressor 13 through the gas pipe 12, the closing valve 12V, and the four-way valve 15.

In addition, in the case of heating operation, the flow is in the opposite direction to that in cooling operation. Gaseous refrigerant compressed by the compressor 13 flows into the indoor heat exchanger 24 through the four-way valve 15, the gas pipe 12, and the closing valve 12V. The refrigerant in the indoor heat exchanger 24 exchanges heat with the surrounding air to warm the surrounding air. The refrigerant that has become liquid through heat exchange flows into the liquid pipe 11, passes through the indoor expansion valve 26, the closing valve 11V, and the outdoor expansion valve 16, and flows into the outdoor heat exchanger 14. The refrigerant in the outdoor heat exchanger 14 exchanges heat with the surrounding air. The refrigerant, which has become gaseous through heat exchange, passes through the four-way valve 15 and returns to the compressor 13.

As described above, the indoor expansion valve 26 controls the flow rate of the refrigerant flowing into each indoor unit 20. The indoor unit control section 29 controls the opening degree of the indoor expansion valve 26 during cooling operation or heating operation to flow a necessary flow rate of refrigerant, and controls the indoor expansion valve 26 to be in a closed state when the operation is stopped. However, foreign matter such as metal powder (for example, copper powder) may get caught in the indoor expansion valve 26, and the indoor expansion valve 26 may not be fully closed during the shutdown. In that case, if another indoor unit 20 connected to the same outdoor unit 10 is in cooling operation, the refrigerant cooled by the outdoor unit 10 also passes through the indoor expansion valve 26 to the indoor unit 20 that is not operating. and flows into the liquid pipe 11 inside the indoor unit 20 and the indoor heat exchanger 24. As a result, when the inside of the indoor unit 20 falls below the dew point temperature, dew condensation occurs, and when the amount of dew increases, dew dripping may occur.

Therefore, the indoor unit control unit 29 monitors the temperature of the indoor heat exchanger 24 while the operation is stopped, and when the temperature falls below a predetermined temperature, rotates the indoor unit fan 27 to prevent condensation from occurring. By rotating the indoor unit fan 27, heat exchange between the refrigerant and the air progresses, the temperature difference between the refrigerant and the air decreases, and the occurrence of dew condensation can be suppressed. Specifically, the indoor unit control unit 29 stops the indoor unit fan 27 and controls the indoor expansion valve 26 to a closed state in response to the stoppage of the indoor unit 20, but when the indoor unit 20 stops operating, the indoor unit control unit 29 When the temperature detected by the exchanger temperature sensor 25 is below a predetermined temperature, the indoor unit fan 27 is rotated.

Here, the predetermined temperature is set as a temperature lower than at least room temperature. For example, the predetermined temperature can be expressed as "room temperature - α". α is a value set in advance based on the dew point temperature. For example, the indoor unit control section 29 determines the above-mentioned predetermined temperature based on the temperature detected by the room temperature sensor 28 and a preset α. Note that when the indoor unit 20 is equipped with a humidity sensor, α may be set based on the dew point temperature based on the detected value of humidity. If there is no humidity sensor, α may be set based on the dew point temperature with humidity as a fixed value. For example, α is set to a value with a margin toward the side where dew condensation is less likely to occur based on the dew point temperature. The margin may be larger when the dew point temperature based on the humidity is a fixed value than when the dew point temperature is based on the detected humidity value. In this way, the predetermined temperature may be set higher than the actual dew point temperature, for example.

Note that the predetermined temperature may be a fixed value (for example, 10° C. or 0° C.) regardless of the room temperature. Further, the predetermined temperature may be changed depending on the outside temperature. For example, the predetermined temperature may be set so that the lower the outside temperature is, the lower the predetermined temperature is, and the higher the outside temperature is, the higher the predetermined temperature is.

Here, when rotating the indoor unit fan 27 while the operation of the indoor unit 20 is stopped, it is preferable that the amount of air blown out is small. That is, it is preferable that the number of revolutions per unit time of the indoor unit fan 27 is small. This is to reduce as much as possible the discomfort caused by the indoor unit fan 27 rotating while the operation is stopped and the feeling of cold air. For example, if the air volume setting (or wind speed setting) during operation has the following options in descending order of air volume: "light wind", "weak wind", "normal", and "strong wind", when the operation is stopped, the air volume is the lowest. "Breeze" may be selected. If there is no air volume setting (or wind speed setting) during operation (in the case of automatic operation), a unique setting with a smaller air volume may be provided as a setting during stoppage of operation. In addition, even if there is an air volume setting (or wind speed setting) during operation, a unique setting with a small air volume of the blowout is set as a setting when the operation is stopped, separate from the air volume setting (or wind speed setting) during operation. You can.

Furthermore, when the indoor unit fan 27 is rotated while the operation is stopped, the indoor unit control section 29 suppresses cold air from hitting the person. For example, the indoor unit control unit 29 controls the direction of the flow of air blown out by the rotation of the indoor unit fan 27 to be in a predetermined direction excluding a direction in which a person may be present indoors. Hereinafter, the direction of the flow of air blown out by the rotation of the indoor unit fan 27 will be referred to as the "blowout direction." Here, the blowing direction when the indoor unit 20 is a wall-mounted type will be explained.

[Ballion direction]
FIG. 2 is an external view showing an example of the wall-mounted indoor unit 20 when the operation is stopped. In this figure, a front view of the wall-mounted indoor unit 20 when the operation is stopped is shown on the left, and a side view is shown on the right. The indoor unit 20 shown in this figure is installed on a wall, with the upward direction in the drawing being directed toward the ceiling and the downward direction being directed toward the floor. Similarly, in FIGS. 3 to 5 described below, the upper direction in the drawings is the ceiling direction, and the lower direction is the floor direction.

FIG. 3 is an external view showing an example of the wall-mounted indoor unit 20 in operation. In this figure, a front view of the wall-mounted indoor unit 20 during normal operation is shown on the left, and a side view is shown on the right. The difference from when the operation is stopped is that the flap 22 provided at the air outlet of the indoor unit 20 is open. The flap 22 is an example of a wind direction plate that changes the direction of air blown out by the rotation of the indoor unit fan 27. The direction of air blown out from the indoor unit 20 corresponds to the angle of the flap 22. The flow of air (airflow) in the wall-mounted indoor unit 20 during operation will be described with reference to FIG. 4.

FIG. 4 is a diagram showing an example of airflow in the wall-mounted indoor unit 20 during operation. This figure is a side sectional view of the indoor unit 20 during operation shown in FIG. 3. Arrows indicate air flow. During operation, the rotation of the indoor unit fan 27 causes air to flow in the following order (1), (2), and (3).
(1) Indoor air is taken into the indoor unit 20.
(2) The taken air passes through the indoor heat exchanger 24.
(3) Then, the air that has been heat exchanged in the indoor heat exchanger 24 is blown out from the indoor unit 20 in a direction that corresponds to the angle of the flap 22.

For example, the angle of the flap 22 during cooling operation is normally controlled so that the blowing direction is below the horizontal direction (towards the floor) in order to lower the temperature in the room or blow cold air onto a person. Ru.

Next, the blowing direction when rotating the indoor unit fan 27 to prevent condensation while the wall-mounted indoor unit 20 is stopped will be described.
FIG. 5 is a diagram showing an example of the blowing direction and airflow when the indoor unit fan 27 is rotated while the operation is stopped. This figure is a side sectional view of a wall-mounted indoor unit 20. The angle of the flap 22 is different from the operating state shown in FIG. 4, and the blowing direction is different. When the indoor unit fan 27 is rotated while the operation is stopped, the angle of the flap 22 is controlled so that the blowing direction is above the horizontal direction (towards the ceiling).

Arrows indicate air flow. When the indoor unit fan 27 is rotated while the operation is stopped, air flows in the following order (1), (2), (3), and (4).
(1) Indoor air is taken into the indoor unit 20.
(2) The taken air passes through the indoor heat exchanger 24.
(3) The air heat-exchanged by the indoor heat exchanger 24 is blown out from the indoor unit 20 in an upward direction (toward the ceiling) rather than the horizontal direction, depending on the angle of the flap 22.
(4) The blown air flows upward (toward the ceiling). Then, returning to (1) above, the air flowing upward is taken into the indoor unit 20 again.

The above (1) to (4) are repeated. The airflow in which steps (1) to (4) are repeated is called a "short cycle." For example, when rotating the indoor unit fan 27 while the operation is stopped, the indoor unit control unit 29 controls the angle of the flap 22 to cause a short cycle. Thereby, when the indoor unit fan 27 is rotated while the operation is stopped, it is possible to suppress cold air from hitting the person.

Next, the operation of rotating the indoor unit fan 27 for the purpose of preventing dew condensation while the indoor unit 20 is stopped will be described. This process is hereinafter referred to as "condensation prevention process."

[First example of start operation of dew condensation prevention process]
FIG. 6 is a flowchart illustrating a first example of an operation for starting dew condensation prevention processing during shutdown according to the present embodiment.
(Step S101) The indoor unit control unit 29 determines whether the indoor unit 20 is stopped. When the indoor unit control unit 29 determines that the operation is being stopped (YES), the process proceeds to step S103. On the other hand, when the indoor unit control section 29 determines that the vehicle is in operation (NO), the indoor unit control section 29 ends the process.

(Step S103) The indoor unit control section 29 detects the temperature of the indoor heat exchanger 24. For example, the indoor unit control section 29 acquires the detected temperature detected by the heat exchanger temperature sensor 25. The indoor unit control section 29 then proceeds to the process of step S105.

(Step S105) The indoor unit control section 29 determines whether the detected temperature detected by the heat exchanger temperature sensor 25 is below a predetermined temperature. When the indoor unit control unit 29 determines that the detected temperature detected by the heat exchanger temperature sensor 25 is equal to or lower than the predetermined temperature (YES), the process proceeds to step S107. On the other hand, when the indoor unit control unit 29 determines that the temperature detected by the heat exchanger temperature sensor 25 is not below the predetermined temperature (NO), the process ends.

(Step S107) The indoor unit control unit 29 controls the flap 22 to an angle that causes a short cycle (see FIG. 5), and proceeds to the process of step S109.

(Step S109) The indoor unit control section 29 rotates the indoor unit fan 27. For example, the indoor unit control unit 29 rotates the indoor unit fan 27 with the air volume setting (or wind speed setting) of "light breeze". Note that the order of processing in step S107 and step S109 may be reversed.

Note that when the indoor unit fan 27 is stopped while the indoor unit 20 is not operating, the indoor unit control section 29 repeatedly executes the operation of starting the dew condensation prevention process shown in FIG. 6 at regular intervals. Further, the indoor unit control section 29 may perform the operation of starting the dew condensation prevention process shown in FIG. 6 when at least one indoor unit 20 other than the indoor unit 20 that is not operating is in operation.

As described above, in the multi-type air conditioner 1 according to the present embodiment, the indoor unit 20 has an indoor expansion valve 26 (expansion An indoor heat exchanger 24 connected to refrigerant piping via a valve (an example of a valve), a heat exchanger temperature sensor 25 (an example of a temperature sensor) that detects the temperature of the indoor heat exchanger 24, and an indoor unit 20 that supplies air to the indoor unit 20. It is provided with an indoor unit fan 27 for blowing out the air heat exchanged by the intake indoor heat exchanger 24. Then, in response to the shutdown, the indoor unit 20 stops the indoor unit fan 27 and closes the indoor expansion valve 26, and during the shutdown, the temperature detected by the heat exchanger temperature sensor 25 reaches a predetermined temperature. In the following cases, the indoor unit fan 27 is rotated.

Thereby, the air conditioner 1 can suppress the occurrence of dew condensation even if the indoor expansion valve 26 of the indoor unit 20 that is not in operation is not fully closed due to foreign matter being caught in the indoor expansion valve 26.

In addition, when the temperature detected by the heat exchanger temperature sensor 25 is below a predetermined temperature while at least one indoor unit 20 other than the indoor unit 20 that is not operating is in operation, the indoor unit 20 is operated by the indoor unit fan. 27 may be rotated.

As a result, even if the air conditioner 1 is not fully closed due to foreign matter getting caught in the indoor expansion valve 26 of the indoor unit 20 that is not operating, the air conditioner 1 can still be operated while the other indoor units 20 are operating. This makes it possible to suppress the occurrence of dew condensation caused by the refrigerant flowing from the outdoor unit 10.

In addition, the wall-mounted indoor unit 20 is equipped with a flap 22 (an example of a wind direction plate) that changes the flow direction (blow direction) of air blown out by the rotation of the indoor unit fan 27. When rotating the flap 27, the flap 22 is controlled so that the blowing direction is upward rather than horizontal.

Thereby, when the air conditioner 1 rotates the indoor unit fan 27 while the operation is stopped, it is possible to suppress cold air from hitting the person.

Further, the control method for the multi-type air conditioner 1 according to the present embodiment includes step S103 in which the heat exchanger temperature sensor 25 detects the temperature of the indoor heat exchanger 24, and in response to the operation stoppage, the indoor unit fan 27 and closes the indoor expansion valve 26, and rotates the indoor unit fan 27 if the temperature detected by the heat exchanger temperature sensor 25 is below a predetermined temperature while the operation is stopped. .

Thereby, the air conditioner 1 can suppress the occurrence of dew condensation even if the indoor expansion valve 26 of the indoor unit 20 that is not in operation is not fully closed due to foreign matter being caught in the indoor expansion valve 26.

[Second example of start operation of dew condensation prevention process]
The indoor unit control section 29 may rotate the indoor unit fan 27 when the heat exchanger temperature sensor 25 detects a temperature below a predetermined temperature for a predetermined time or longer while the indoor unit 20 is stopped. The predetermined period of time is preset as a period of time to exclude cases where the temperature detected by the heat exchanger temperature sensor 25 instantaneously becomes equal to or lower than the predetermined temperature. Further, the predetermined time is preset as a time period until dew condensation does not occur when the temperature detected by the heat exchanger temperature sensor 25 is continuously lower than a predetermined temperature. As an example, the predetermined time is set to about 5 minutes.

FIG. 7 is a flowchart illustrating a second example of an operation for starting dew condensation prevention processing during a shutdown period according to the present embodiment. In this figure, the same reference numerals are given to the processes corresponding to the processes in FIG. 6, and the explanation thereof will be omitted. The process shown in FIG. 7 differs from the process in step S105 in FIG. 6 in step S105A.

(Step S105A) The indoor unit control unit 29 determines whether the heat exchanger temperature sensor 25 detects a temperature below a predetermined temperature for a predetermined period or longer. If the indoor unit control unit 29 determines that the heat exchanger temperature sensor 25 detects a temperature below the predetermined temperature for a predetermined period of time or more (YES), the process proceeds to step S107. On the other hand, when the indoor unit control unit 29 determines that the heat exchanger temperature sensor 25 has not detected a temperature below the predetermined temperature for a predetermined period of time or more (NO), the process ends.

Note that the indoor unit control unit 29 may perform the operation of starting the dew condensation prevention process shown in FIG. 7 when at least one indoor unit 20 other than the indoor unit 20 that is not operating is in operation.

As described above, in the air conditioner 1 according to the present embodiment, when the indoor unit 20 detects a temperature below a predetermined temperature by the heat exchanger temperature sensor 25 for a predetermined period of time or more while the operation is stopped, the indoor unit fan Rotate 27.

Thereby, the air conditioner 1 can suppress the occurrence of dew condensation even if the indoor expansion valve 26 of the indoor unit 20 that is not in operation is not fully closed due to foreign matter being caught in the indoor expansion valve 26.

In addition, when the indoor unit 20 detects a temperature below a predetermined temperature for a predetermined period of time or more by the heat exchanger temperature sensor 25 while at least one indoor unit 20 other than the indoor unit 20 that is not operating is in operation, The indoor unit fan 27 may be rotated.

As a result, even if the air conditioner 1 is not fully closed due to foreign matter getting caught in the indoor expansion valve 26 of the indoor unit 20 that is not operating, the air conditioner 1 can still be operated while the other indoor units 20 are operating. This makes it possible to suppress the occurrence of dew condensation caused by the refrigerant flowing from the outdoor unit 10.

[First example of stopping operation of dew condensation prevention process]
Further, when the dew condensation prevention process is started while the indoor unit 20 is stopped, the temperature of the refrigerant flowing into the indoor unit 20 increases due to heat exchange. The indoor unit control section 29 stops the indoor unit fan 27 and stops the dew condensation prevention process when the temperature detected by the heat exchanger temperature sensor 25 reaches a predetermined temperature or higher. Here, the predetermined temperature used for determining when to stop the dew condensation prevention process is set to a higher temperature than the predetermined temperature used for determining when to start the dew condensation prevention process. For example, if the predetermined temperature used to determine when to start dew condensation prevention processing is 10°C, the predetermined temperature used to determine when to stop dew condensation prevention processing may be set to 15°C, 20°C, etc. .

Note that the predetermined temperature used for the determination when stopping the dew condensation prevention process is set so that the lower the room temperature is, the lower the predetermined temperature is, and the higher the room temperature is, the higher the predetermined temperature is. Further, the predetermined temperature used for determining when stopping the dew condensation prevention process may be set to be lower as the outside temperature is lower, and higher as the outside temperature is higher.

FIG. 8 is a flowchart illustrating a first example of an operation for stopping the dew condensation prevention process during an operation stop according to the present embodiment. When the indoor unit fan 27 is being rotated while the indoor unit 20 is stopped, the indoor unit control unit 29 performs the process shown in FIG. 8 at a constant cycle.

(Step S121) The indoor unit control section 29 detects the temperature of the indoor heat exchanger 24. For example, the indoor unit control section 29 acquires the detected temperature detected by the heat exchanger temperature sensor 25. The indoor unit control unit 29 then proceeds to the process of step S123.

(Step S123) The indoor unit control section 29 determines whether the detected temperature detected by the heat exchanger temperature sensor 25 is equal to or higher than a predetermined temperature. When the indoor unit control unit 29 determines that the detected temperature detected by the heat exchanger temperature sensor 25 is equal to or higher than the predetermined temperature (YES), the process proceeds to step S125. On the other hand, when the indoor unit control unit 29 determines that the temperature detected by the heat exchanger temperature sensor 25 is not equal to or higher than the predetermined temperature (NO), the process ends.

(Step S125) The indoor unit control unit 29 stops the indoor unit fan 27, and proceeds to the process of step S127.
(Step S127) The indoor unit control section 29 controls the flap 22 to the angle at which the operation is stopped. Note that the processing order of step S125 and step S127 may be reversed.

In this manner, the indoor unit 20 stops the indoor unit fan 27 when the temperature detected by the heat exchanger temperature sensor 25 becomes equal to or higher than the predetermined temperature while the indoor unit 20 is stopped.

Thereby, the air conditioner 1 can stop the indoor unit fan 27 when the temperature of the refrigerant rises to a temperature at which no condensation occurs. Therefore, the air conditioner 1 does not rotate the indoor unit fan 27 more than necessary while the air conditioner 1 is not operating, and can reduce power consumption for suppressing the occurrence of dew condensation.

[Second example of stopping operation of anti-condensation process]
The indoor unit control section 29 may stop the indoor unit fan 27 when the heat exchanger temperature sensor 25 detects a temperature equal to or higher than a predetermined temperature for a predetermined period of time while the indoor unit 20 is stopped. The predetermined time is preset as a time to exclude cases where the temperature detected by the heat exchanger temperature sensor 25 instantaneously becomes equal to or higher than the predetermined temperature. As an example, the predetermined time is set to about 5 minutes.

FIG. 9 is a flowchart illustrating a second example of the operation of stopping the dew condensation prevention process during an operation stop according to the present embodiment. In this figure, the same reference numerals are given to the processes corresponding to the processes in FIG. 8, and the explanation thereof will be omitted. The process shown in FIG. 9 differs from the process in step S123 in FIG. 8 in step S123A.

(Step S123A) The indoor unit control unit 29 determines whether or not the heat exchanger temperature sensor 25 detects a temperature equal to or higher than a predetermined temperature for a predetermined time or longer. When the indoor unit control unit 29 determines that the heat exchanger temperature sensor 25 detects a temperature equal to or higher than the predetermined temperature for a predetermined period of time or more (YES), the process proceeds to step S125. On the other hand, when the indoor unit control unit 29 determines that the heat exchanger temperature sensor 25 has not detected a temperature equal to or higher than the predetermined temperature for a predetermined period of time or more (NO), the process ends.

In this manner, the indoor unit 20 stops the indoor unit fan 27 when the heat exchanger temperature sensor 25 detects a temperature equal to or higher than a predetermined temperature for a predetermined period of time during the shutdown.

Thereby, the air conditioner 1 can stop the indoor unit fan 27 when the temperature of the refrigerant rises to a temperature at which no condensation occurs. Therefore, the air conditioner 1 does not rotate the indoor unit fan 27 more than necessary while the air conditioner 1 is not operating, and can reduce power consumption for suppressing the occurrence of dew condensation.

[Notification processing]
When the condensation prevention process is stopped by the operation shown in FIG. 8 or 9, the refrigerant cooled by the outdoor unit 10 will continue to flow to the indoor unit 2 unless the foreign object stuck in the indoor expansion valve 26 comes off for some reason. flow into. Furthermore, even if the foreign object stuck in the indoor expansion valve 26 is removed, if a scratch or the like occurs due to the foreign object, the indoor expansion valve 26 will not be fully closed and the refrigerant will continue to flow into the indoor unit 20. Sometimes I do. Then, the temperature of the indoor heat exchanger 24 decreases again.

When the indoor unit control section 29 stops the dew condensation prevention process, it repeatedly executes the operation of starting the dew condensation prevention process shown in FIG. 6 or 7 at regular intervals. Then, when the indoor unit control unit 29 determines that the detected temperature detected by the heat exchanger temperature sensor 25 is below a predetermined temperature, or when it is determined that the temperature below the predetermined temperature has been detected for a predetermined period of time or more. , restart the anti-condensation process. If the indoor unit fan 27 rotates and stops a predetermined number of times (for example, five times) or more while the indoor unit 20 is stopped, the indoor unit control unit 29 outputs notification information and notifies the user.

For example, when the indoor unit fan 27 rotates and stops a predetermined number of times or more while the indoor unit 20 is stopped, the indoor unit control unit 29 causes the remote controller 30 to display notification information. The notification information is, for example, a message prompting maintenance, a message informing about the contents of an abnormality, and the like.

FIG. 10 is a flowchart illustrating an example of the operation of notification processing according to this embodiment.
(Step S131) The indoor unit control unit 29 determines whether the indoor unit 20 is stopped. When the indoor unit control unit 29 determines that the operation is being stopped (YES), the process proceeds to step S133. On the other hand, when the indoor unit control unit 29 determines that the vehicle is in operation (NO), it ends the notification process.

(Step S133) The indoor unit control unit 29 counts the number of times (number of repetitions) that the indoor unit fan 27 is repeatedly rotated and stopped while the indoor unit 20 is stopped, and proceeds to the process of step S135.

(Step S135) The indoor unit control unit 29 determines whether the number of repetitions of rotation and stop of the indoor unit fan 27 is equal to or greater than a predetermined number of times. If the indoor unit control unit 29 determines that the number of times the indoor unit fan 27 repeats rotation and stop is equal to or greater than the predetermined number of times (YES), the process proceeds to step S137. On the other hand, if the indoor unit control unit 29 determines that the number of times the indoor unit fan 27 repeats rotation and stop is less than the predetermined number of times (NO), the process returns to step S131.

(Step S137) The indoor unit control unit 29 causes the remote control 30 to display the notification information. For example, the indoor unit control unit 29 transmits a message urging maintenance to the remote controller 30, and displays the message on a display included in the remote controller 30.

In this way, the indoor unit 20 outputs notification information when the control of rotating and stopping the indoor unit fan 27 is repeated a predetermined number of times or more while the indoor unit fan 27 is stopped. For example, the indoor unit 20 causes a remote control 30 (an example of a terminal device) for operating the indoor unit 20 that is not operating to display a message urging maintenance as notification information.

Thereby, the air conditioner 1 can make the user aware of the abnormality (failure) of the indoor expansion valve 26, and can prompt the user to request repair.

Note that the indoor unit control section 29 may cause the indoor unit 20 to display notification information when the indoor unit fan 27 repeats rotation and stop a predetermined number of times or more while the indoor unit 20 is stopped. For example, when the indoor unit 20 includes a display, the indoor unit control section 29 may display the notification information on the display. In addition, the indoor unit control unit 29 may cause a display lamp (such as an LED) that notifies the operating state (such as running) or error state of the indoor unit 20 to light up or blink in a specific color as the above-mentioned notification information. . Furthermore, the notification information is not limited to information that is displayed, but may also be information that is output as sound or audio.

<Second embodiment>
Next, a second embodiment will be described.
In the first embodiment, a case where the indoor unit 20 is a wall-mounted type has been described with reference to FIGS. 2 to 5, but in this embodiment, a case where the indoor unit 20 is a ceiling-embedded type will be described. The wall-mounted type and the ceiling-embedded type differ in the blowing direction when rotating the indoor unit fan 27 to prevent condensation while the operation is stopped.

For example, in the case of a ceiling-embedded indoor unit 20, the indoor unit control unit 29 controls the indoor unit controller 29 so that the blowing direction of air blown out by the rotation of the indoor unit fan 27 is closer to the horizontal direction than the vertical direction. Control. As with the wall-mounted type, this prevents cold air from hitting the person. Hereinafter, with reference to FIGS. 11 to 14, the blowing direction in the ceiling-embedded indoor unit 20 will be described.

FIG. 11 is an external view showing an example of a ceiling-embedded indoor unit 20. This figure is a diagram of the indoor unit 20 installed on the ceiling viewed from below (floor side). A flap 22 is provided at each of four air outlets corresponding to each of the four sides of the square housing.

FIG. 12 is a diagram showing an example of the ceiling-embedded indoor unit 20 when the operation is stopped. This figure is a sectional view of the indoor unit 20 when viewed from the side (horizontal direction), and shows one of the four air outlets in an enlarged manner. While the operation is stopped, the indoor unit fan 27 is stopped and the flap 22 is also closed.

FIG. 13 is a diagram showing the blowing direction of the ceiling-mounted indoor unit 20 during operation. This figure is a cross-sectional view of the indoor unit 20 when viewed from the side (horizontal direction), similar to FIG. 12, and shows one of the four air outlets in an enlarged manner. Although detailed illustrations of airflow are omitted, as in the case of the wall-mounted type, indoor air is taken into the indoor unit 20 by the rotation of the indoor unit fan 27, and the air is heat-exchanged by the indoor heat exchanger 24. is blown out according to the angle of the flap 22. For example, the angle of the flap 22 during cooling operation is normally controlled so that the blowing direction is closer to the vertical direction than the horizontal direction in order to lower the temperature in the room or blow cold air onto a person. .

FIG. 14 is a diagram showing the blowing direction when the indoor unit fan 27 is rotated while the operation is stopped. This figure is a cross-sectional view of the indoor unit 20 when viewed from the side (horizontal direction), similar to FIGS. 12 and 13, and shows one of the four air outlets in an enlarged manner. The angle of the flap 22 is different from the operating state shown in FIG. 12, and the blowing direction is different. When the indoor unit fan 27 is rotated while the operation is stopped, the angle of the flap 22 is controlled so that the blowing direction is closer to the horizontal direction than the vertical direction. For example, the angle of the flap 22 is controlled so that the blowing direction is horizontal along the ceiling surface, that is, the so-called smudging direction. For example, when rotating the indoor unit fan 27 while the operation is stopped, the indoor unit control unit 29 controls the angle of the flap 22 to cause smudging. Thereby, when the indoor unit fan 27 is rotated while the operation is stopped, it is possible to suppress cold air from hitting the person.

Here, the operation of the process according to this embodiment will be explained. The start operation of the dew condensation prevention process in the ceiling-mounted indoor unit 20 differs from the start operation of the dew condensation prevention process in the wall-mounted indoor unit 20 shown in FIG. 6 or 7 only in the control of the angle of the flap 22. . For example, in step S107, the indoor unit control unit 29 controls the flap 22 to an angle for smudging (see FIG. 14), and proceeds to the process of step S109. Other processing is the same.

Further, the operation of stopping the condensation prevention process in the ceiling-mounted indoor unit 20 is similar to the operation of starting the dew condensation prevention process in the wall-mounted indoor unit 20 shown in FIG. 8 or 9. Further, the notification processing operation in the ceiling-embedded indoor unit 20 is similar to the notification processing operation in the wall-mounted indoor unit 20 shown in FIG.

As described above, the ceiling-embedded indoor unit 20 according to the present embodiment has a flap 22 (an example of a wind direction plate) that changes the flow direction (blow direction) of air blown out by the rotation of the indoor unit fan 27. ), and when the indoor unit fan 27 is rotated while the operation is stopped, the flap 22 is controlled so that the blowing direction is closer to the horizontal direction than the vertical direction.

Thereby, when the air conditioner 1 rotates the indoor unit fan 27 while the operation is stopped, it is possible to suppress cold air from hitting the person.

Although each embodiment has been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and each embodiment may be combined, modified, or omitted as appropriate. It is possible to

Although the remote control 30 is illustrated as an example of a terminal device that communicates with the indoor unit 20, a smartphone, a tablet-type PC (Personal Computer), or the like may be used instead of the remote control 30.

In the above embodiment, an example was shown in which the indoor unit control section 29 executes the dew condensation prevention process, but by acquiring information on each part of the indoor unit 20 from the indoor unit control section 29, the outdoor unit control section 19 or the remote control 30 A terminal device such as the above may execute at least a part of the dew condensation prevention process. Alternatively, a server connected to the indoor unit control section 29 via a communication network may perform at least part of the condensation prevention process by acquiring information about each part of the indoor unit 20 from the indoor unit control section 29. good.

Note that a program for realizing each function of the outdoor unit control section 19 and the indoor unit control section 29 is recorded on a computer-readable recording medium, and the program recorded on this recording medium is read into the computer system, By executing this, the processes of the outdoor unit control section 19 and the indoor unit control section 29 may be performed. Note that the "computer system" herein includes hardware such as an OS and peripheral devices.

Furthermore, the term "computer-readable recording medium" refers to portable media such as flexible disks, magneto-optical disks, ROMs, and CD-ROMs, and storage devices such as hard disks built into computer systems. Furthermore, a "computer-readable recording medium" refers to a storage medium that dynamically stores a program for a short period of time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. This includes things that retain programs for a certain period of time, such as volatile memory inside a computer system that serves as a server or client. Further, the above-mentioned program may be one for realizing a part of the above-mentioned functions, or may be one that can realize the above-mentioned functions in combination with a program already recorded in the computer system. Alternatively, the above program may be stored in a predetermined server, and the program may be distributed (downloaded, etc.) via a communication line in response to a request from another device.

Further, a part or all of the functions of the outdoor unit control section 19 and the indoor unit control section 29 may be realized as an integrated circuit such as an LSI (Large Scale Integration). Each function may be implemented as an individual processor, or a part or all of them may be integrated into a processor. Further, the method of circuit integration is not limited to LSI, but may be implemented using a dedicated circuit or a general-purpose processor. Further, if an integrated circuit technology that replaces LSI emerges due to advances in semiconductor technology, an integrated circuit based on this technology may be used.

1 Air conditioner, 10 Outdoor unit, 11 Liquid pipe, 11V closing valve, 12 Gas pipe, 12V closing valve, 13 Compressor, 14 Outdoor heat exchanger, 15 Four-way valve, 16 Outdoor expansion valve, 17 Outdoor unit fan, 18 Outside temperature sensor, 19 Outdoor unit control unit, 20 Indoor unit, 23 Receiving unit, 24 Indoor heat exchanger, 25 Heat exchanger temperature sensor, 26 Indoor expansion valve, 27 Indoor unit fan, 28 Room temperature sensor, 29 Indoor unit control unit , 30 remote control

Claims (10)

An air conditioner comprising one outdoor unit and a plurality of indoor units each connected to refrigerant pipes through which refrigerant sent from the outdoor unit flows,
an indoor heat exchanger connected to the refrigerant pipe via an expansion valve that controls the flow rate of the refrigerant flowing through the refrigerant pipe;
a temperature sensor that detects the temperature of the indoor heat exchanger;
an indoor unit fan for taking air into the indoor unit and blowing out the air heat-exchanged by the indoor heat exchanger;
In response to the shutdown of the indoor unit, the indoor unit fan is stopped and the expansion valve is closed, and when the temperature detected by the temperature sensor is below a predetermined temperature while the indoor unit is stopped. a control unit that rotates the indoor unit fan;
Equipped with
The control unit includes:
If the temperature detected by the temperature sensor becomes a predetermined temperature or higher while the indoor unit is stopped, the indoor unit fan is stopped;
outputting notification information when control of rotation and stop of the indoor unit fan is repeated a predetermined number of times or more while the indoor unit is stopped;
Air conditioner. The control unit includes:
rotating the indoor unit fan if the temperature sensor detects a temperature below a predetermined temperature for a predetermined time or more while the indoor unit is stopped;
The air conditioner according to claim 1. The control unit includes:
rotating the indoor unit fan if the temperature detected by the temperature sensor is equal to or lower than a predetermined temperature while at least one indoor unit other than the indoor unit that is not in operation is in operation;
The air conditioner according to claim 1. The control unit includes:
rotating the indoor unit fan when the temperature sensor detects a temperature below a predetermined temperature for a predetermined period of time or more while at least one of the indoor units other than the indoor unit that is not in operation is in operation;
The air conditioner according to claim 2. The indoor unit whose operation is stopped is a wall-mounted indoor unit,
The indoor unit is
comprising a wind direction plate that changes the direction of the flow of the air blown out by rotation of the indoor unit fan;
The control unit includes:
When rotating the indoor unit fan while the indoor unit is stopped, controlling the wind direction plate so that the direction of the air flow is upward than the horizontal direction;
The air conditioner according to any one of claims 1 to 4. The indoor unit whose operation is stopped is a ceiling-mounted indoor unit,
The indoor unit is
comprising a wind direction plate that changes the direction of the flow of the air blown out by rotation of the indoor unit fan;
The control unit includes:
When rotating the indoor unit fan while the indoor unit is stopped, controlling the wind direction plate so that the direction of the air flow is closer to the horizontal direction than the vertical direction;
The air conditioner according to any one of claims 1 to 4. The control unit includes:
Stopping the indoor unit fan if the temperature sensor detects a temperature equal to or higher than a predetermined temperature for a predetermined period of time while the indoor unit is stopped;
The air conditioner according to any one of claims 1 to 6 . further comprising a terminal device that communicates with the indoor unit,
The control unit displays the notification information on the terminal device,
The air conditioner according to claim 1. The notification information is a message prompting maintenance or a message informing about abnormality,
The air conditioner according to claim 1 or claim 8. An air conditioner comprising one outdoor unit and a plurality of indoor units each connected to a refrigerant pipe through which refrigerant sent from the outdoor unit flows, the air conditioner controlling the flow rate of the refrigerant flowing through the refrigerant pipe. An indoor heat exchanger connected to the refrigerant piping via an expansion valve, a temperature sensor for detecting the temperature of the indoor heat exchanger, and a temperature sensor for detecting the temperature of the indoor heat exchanger; A control method in the air conditioner, each of the indoor units including an indoor unit fan for blowing air,
the temperature sensor detecting the temperature of the indoor heat exchanger;
The control unit stops the indoor unit fan and closes the expansion valve in response to the shutdown of the indoor unit, and controls the temperature detected by the temperature sensor to a predetermined value while the indoor unit is stopped. rotating the indoor unit fan if the temperature is below;
a step in which the control unit stops the indoor unit fan if the temperature detected by the temperature sensor becomes a predetermined temperature or higher while the indoor unit is stopped;
outputting notification information when the control unit repeats rotation and stop control of the indoor unit fan a predetermined number of times or more while the indoor unit is stopped;
control methods including.

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