EP4656963A1

EP4656963A1 - Air conditioner and control method

Info

Publication number: EP4656963A1
Application number: EP24756583.1A
Authority: EP
Inventors: Hirofumi Ishizuka
Original assignee: Mitsubishi Heavy Industries Thermal Systems Ltd
Current assignee: Mitsubishi Heavy Industries Thermal Systems Ltd
Priority date: 2023-02-16
Filing date: 2024-01-23
Publication date: 2025-12-03
Also published as: WO2024171732A1; EP4656963A4; JP2024116685A

Abstract

Provided is an air conditioner in which a coolant sensor is disposed near a heat exchanger and it is possible to prevent failure of the coolant sensor due to humidity. This air conditioner includes: an indoor unit that includes a fan, a heat exchanger, and a coolant sensor provided in the vicinity of the heat exchanger; an outdoor unit; and a control device. The control device operates the fan for a predetermined set time, which is the time required to exhaust air inside the indoor unit when the cooling operation is stopped.

Description

Technical Field

The present disclosure relates to an air conditioner and a control method. The present disclosure claims priority based on Japanese Patent Application No. 2023-022432, filed in Japan on February 16, 2023 , the content of which is incorporated herein by reference.

Background Art

In some cases, a refrigerant detection sensor is provided in an air conditioner for detection of refrigerant leakage. As a refrigerant sensor for the air conditioner, a semiconductor-type refrigerant sensor, which is inexpensive, is generally used. Since dew condensation causes failure of the semiconductor-type refrigerant sensor, the probability of failure increases when the semiconductor-type refrigerant sensor is disposed in a high-humidity environment. For detection of leakage of a refrigerant from a heat exchanger, it is desirable that the refrigerant sensor is provided near the heat exchanger. However, due to the influence of condensed water, the vicinity of the heat exchanger is made highest in humidity when a fan is stopped after a cooling operation. In such an environment, it is difficult to use the semiconductor-type refrigerant sensor.
Disclosed in PTL 1 is a technique in which a refrigerant sensor (a gas detecting unit 60) is disposed upstream of a heat exchanger in a direction in which air flows in an air path formed in a casing of an indoor unit and control in which an evaporation temperature of the heat exchanger is increased within a range lower than a dew-point temperature is performed when there is an increase in humidity in the indoor unit so that generation of dew condensation water to the heat exchanger and the influence of the dew condensation water on the refrigerant sensor are suppressed.

Citation List

Patent Literature

[PTL 1] Japanese Unexamined Patent Application Publication No. 2021-103053

Summary of Invention

Technical Problem

There is a demand for a technique to prevent failure of a refrigerant sensor that is caused by a high level of humidity while disposing the refrigerant sensor near a heat exchanger.
The present disclosure provides an air conditioner and a control method with which it is possible to solve the problem as described above.

Solution to Problem

According to an aspect of the present disclosure, there is provided an air conditioner including an indoor unit that includes a fan, a heat exchanger, and a refrigerant sensor provided in a vicinity of the heat exchanger, an outdoor unit, and a control device, in which, at a time of stoppage of a cooling operation, the control device operates the fan for a predetermined set time, which is a time required to discharge air in the indoor unit.
According to an aspect of the present disclosure, there is provided a control method for an air conditioner including an indoor unit that includes a fan, a heat exchanger, and a refrigerant sensor provided in a vicinity of the heat exchanger, and an outdoor unit, the method including operating, at a time of stoppage of a cooling operation, the fan for a predetermined set time, which is a time required to discharge air in the indoor unit.

Advantageous Effects of Invention

According to an air conditioner and a control method described above, it is possible to prevent failure of a refrigerant sensor that is caused by a high level of humidity while disposing the refrigerant sensor near a heat exchanger.

Brief Description of Drawings

Fig. 1 is a first view schematically showing an example of an air conditioner according to an embodiment.
Fig. 2 is a second view schematically showing an example of the air conditioner according to the embodiment.
Fig. 3 is a block diagram showing an example of a control device of the air conditioner according to the embodiment.
Fig. 4 is a diagram for description of fan control of failure prevention control according to the embodiment.
Fig. 5 is a first flowchart showing an example of the failure prevention control according to the embodiment.
Fig. 6 is a second flowchart showing an example of the failure prevention control according to the embodiment.

Description of Embodiments

Hereinafter, an air conditioner according to an embodiment of the present disclosure will be described with reference to Figs. 1 to 6.

(Configuration)

Fig. 1 is a view schematically showing the air conditioner according to the embodiment. The air conditioner 1 includes an indoor unit 10, an outdoor unit 20, and a remote controller 30. The indoor unit 10 is connected to the outdoor unit 20 by a refrigerant pipe 18. The outdoor unit 20 includes a compressor, an expansion valve, a heat exchanger for the outdoor unit, and a four-way valve which are not shown, and the indoor unit 10 and the outdoor unit 20 constitute a refrigeration cycle. The air conditioner 1 heats and cools a refrigerant by causing the refrigerant to circulate in the refrigeration cycle. The indoor unit 10 of the air conditioner 1 shown in Fig. 1 includes an intake port 11, a fan 12, a heat exchanger 13, a discharge outlet 14, a sensor casing 15, and a control device 100, the air conditioner 1 being a duct type air conditioner or a ceiling-mounted type air conditioner. In the indoor unit 10, air flows in a direction represented by arrows. The indoor unit 10 drives the fan 12 to cause air to be sucked in through the intake port 11 and adjusts the temperature of the sucked air to an appropriate temperature by using the heat exchanger 13, so that air subjected to air conditioning is supplied into a room through the discharge outlet 14. The sensor casing 15 is provided in the vicinity of the heat exchanger 13, and a refrigerant sensor 16 and a humidity sensor 17 are stored in the sensor casing 15. The vicinity of the heat exchanger 13 is a region of which the humidity is made high due to the influence of the heat exchanger 13, and is a region H1 including the heat exchanger 13 and the discharge outlet 14 that are downstream of the fan 12 in a direction in which air flows. The refrigerant sensor 16 is, for example, a semiconductor-type refrigerant sensor. The refrigerant sensor 16 detects a refrigerant that has leaked from the heat exchanger 13. The humidity sensor 17 measures the humidity of air around the refrigerant sensor 16. Although Fig. 1 shows a configuration example of a case where the refrigerant sensor 16 and the humidity sensor 17 are provided in the sensor casing 15, only the refrigerant sensor 16 may be stored in the sensor casing 15. Later, Fig. 2 shows a configuration example in which the humidity sensor 17 is not shown.
The control device 100 is connected to the refrigerant sensor 16 and the humidity sensor 17. The control device 100 is connected to the remote controller 30 such that the control device 100 can communicate with the remote controller 30. The control device 100 controls the indoor unit 10. For example, the control device 100 performs the operating of the fan 12, the stopping of the fan 12, or the like. The control device 100 communicates with the remote controller 30 to control the operation of the air conditioner 1. For example, when a user issues an instruction to start a cooling operation by operating the remote controller 30, the control device 100 receives a signal of the instruction from the remote controller 30 and performs the cooling operation in cooperation with the outdoor unit 20. When the user issues an instruction to stop the cooling operation by operating the remote controller 30, the control device 100 receives a signal of the instruction from the remote controller 30 and stops the cooling operation. When the refrigerant sensor 16 detects refrigerant leakage, the control device 100 executes a protection operation of the air conditioner 1 or instructs the remote controller 30 to perform notification with an alarm.
When the fan 12 is stopped after the start of the cooling operation because the cooling operation is ended due to the instruction issued by the user or the indoor temperature reaches a set temperature, the humidity of air around the heat exchanger 13 increases, which may result in dew condensation. In the case of a switch from the cooling operation to a heating operation in a multisystem, the temperature of air around the heat exchanger 13 may be made high at the time of stoppage of the heating operation as well, which may result in an increase in humidity. The semiconductor-type refrigerant sensor 16 is vulnerable to a high level of humidity, and a high-humidity environment causes failure of the refrigerant sensor 16. Therefore, the control device 100 performs failure prevention control in which the fan 12 is operated for a short time at the time of stoppage (at the time of stoppage of the fan 12) or the like of a cooling operation so that air in the indoor unit is discharged and the humidity of air around the refrigerant sensor 16 is reduced.
Fig. 2 shows a ceiling-embedded type air conditioner 1A. The air conditioner 1A includes an indoor unit 10A, the outdoor unit 20, and the remote controller 30. The indoor unit 10A includes an intake port 11A, a fan 12A, heat exchangers 13A, discharge outlets 14A, a sensor casing 15A, and a control device 100A. In the indoor unit 10A, air flows in directions represented by arrows. The sensor casing 15A is provided in the vicinities of the heat exchangers 13A, and the refrigerant sensor 16 is stored in the sensor casing 15A. The vicinities of the heat exchanger 13A are regions H2 including the heat exchangers 13A and the discharge outlets 14A that are downstream of the fan 12A in the directions in which air flows. The refrigerant sensor 16 and the humidity sensor 17 may be stored in the sensor casing 15A. The control device 100A controls the fan 12A, the remote controller 30, and the like. The control device 100A performs failure prevention control.

(Control Device)

Fig. 3 is a block diagram showing an example of the control device according to the embodiment. Although the control devices 100 and 100A are respectively shown in Figs. 1 and 2, the functions thereof are the same as each other. Therefore, following description will be made based on the configuration in Fig. 1.
The control device 100 is, for example, a computer including a central processing unit (CPU) such as a microcomputer or a micro processing unit (MPU). The control device 100 includes a sensor information acquisition unit 101, an air conditioner control unit 102, a remote controller control unit 103, a timer 104, and a storage unit 105.
The sensor information acquisition unit 101 acquires the amount of a refrigerant measured by the refrigerant sensor 16 and humidity measured by the humidity sensor 17.
The air conditioner control unit 102 controls each part of the indoor unit 10 and operation of the air conditioner 1. For example, the air conditioner control unit 102 controls operation of the fan 12.
The remote controller control unit 103 communicates with the remote controller 30 to receive an instruction signal input by a user or to transmit, to the remote controller 30, instruction information including information to be displayed by the remote controller 30. The remote controller 30 displays, based on the transmitted instruction information, information that the user is to be notified of.
The timer 104 measures a time. For example, the air conditioner control unit 102 uses the timer 104 to measure a time (for example, 10 seconds or the like) for which the fan 12 is operated or the time interval at which the fan 12 is operated.
The storage unit 105 stores measured values acquired by the sensor information acquisition unit 101, a threshold value used for the failure prevention control, an operation time of the fan 12, the time interval at which the fan 12 is operated, and the like. The storage unit 105 stores various programs that realize the functions of the control device 100.

(Failure Prevention Control for Refrigerant Sensor)

Next, fan control of the failure prevention control according to the embodiment will be described with reference to Fig. 4.

[1] Case Where Humidity Sensor 17 Is Used

In a case where the humidity sensor 17 is used, the air conditioner control unit 102 operates the fan 12 for a short time at a predetermined rotation speed when humidity measured by the humidity sensor 17 at the time of stoppage of the fan 12 after a cooling operation is equal to or higher than a threshold value (a value indicating a saturated state, for example, relative humidity of 95% or higher). The short time is not a time required to dry the inside of the indoor unit 10 but a time required to discharge air in the indoor unit 10. A time of 30 seconds or less is set as the short time. (Since 1 m³ of air circulates even in 10 seconds, 10 seconds or less is also acceptable) In a case where the humidity becomes equal to or higher than the threshold value again even after air is sent for the short time, the air conditioner control unit 102 operates the fan 12 for the short time. The air conditioner control unit 102 repeats such control. Accordingly, high-humidity air is discharged to the outside of the indoor unit 10 and thus the humidity of air around the heat exchanger 13 can be reduced. Since the humidity of air around the heat exchanger 13 is reduced, failure of the refrigerant sensor 16 can be prevented.

[2] Case where Humidity Sensor 17 Is Not Used

In a case where the humidity sensor 17 is not used since the humidity sensor 17 is not provided or the like, the air conditioner control unit 102 intermittently repeats operating the fan 12 for a short time when the fan 12 is stopped after a cooling operation. The short time is a time required to discharge air in the indoor unit 10, and a value of 30 seconds or less (in many cases, 10 seconds or less is acceptable) is set as the short time. For example, after a lapse of five minutes from stoppage of the fan (if the fan 12 is stopped for the five minutes), the air conditioner control unit 102 operates the fan 12 once for the short time. Thereafter, the air conditioner control unit 102 intermittently operates the fan 12 while gradually increasing the interval at which the fan 12 is operated in such a manner that the fan 12 is operated once for the short time after a lapse of six minutes, the fan 12 is operated once for the short time after a lapse of seven minutes, the fan 12 is operated once for the short time after a lapse of eight minutes, ... and so on. The air conditioner control unit 102 may continue, while the fan 12 is stopped, control in which the fan 12 is driven for a short time while being operated at intervals or may end the control after the control is repeated a predetermined number of times. In the above-described example, the interval at which the fan 12 is operated is gradually increased because the amount of high-humidity air is reduced as the fan 12 is repeatedly operated. However, for example, the fan 12 may be periodically operated for the short time each time five minutes elapse. Accordingly, high-humidity air is discharged to the outside of the indoor unit 10 and the humidity of air around the heat exchanger 13 is reduced, so that failure of the refrigerant sensor 16 can be prevented.

(Operation)

Next, the flow of the failure prevention control will be described with reference to Figs. 5 and 6.

Case where Humidity Sensor Is Used

Fig. 5 is a first flowchart showing an example of the failure prevention control according to the embodiment.
The air conditioner control unit 102 detects stoppage of a cooling operation (step S11). The stoppage of the cooling operation refers to the end of the cooling operation that is caused by an instruction issued by a user or temporal stoppage of the cooling operation that is caused because the indoor temperature reaches a set cooling temperature. The fan 12 is stopped because of the stoppage of the cooling operation. Next, the air conditioner control unit 102 monitors humidity that is measured by the humidity sensor 17 and that is acquired by the sensor information acquisition unit 101 and determines whether or not air around the heat exchanger 13 is in a saturated state. For example, the air conditioner control unit 102 determines that the air is in the saturated state when the value of relative humidity that is measured by the humidity sensor 17 is 95% or higher, and determines that the air is not in a saturated state in other cases. In a case where the air is not in the saturated state (step S12; No), the air conditioner control unit 102 continues to monitor the humidity measured by the humidity sensor 17. In a case where the air is in the saturated state (step S12; Yes), the remote controller control unit 103 transmits instruction information to instruct the remote controller 30 to notify the user that the fan 12 will be operated. The remote controller 30 receives the instruction information. The remote controller 30 performs, based on the received instruction information, notification indicating that the fan 12 will be operated (step S13). For example, the remote controller 30 displays a message such as "the fan will be operated for a short time" on a display unit (not shown) of the remote controller 30. Accordingly, the user's concern or doubt about the fan 12 being driven even during stoppage of the operation can be eliminated. Next, the air conditioner control unit 102 operates the fan 12 for a short time (30 seconds or less) (step S14). Accordingly, high-humidity air around the heat exchanger 13 is discharged to the inside of a room and thus a humidity in the indoor unit 10 can be reduced. When a short-time operation is finished, processes after step S12 are repeatedly executed. Accordingly, the humidity of air around the heat exchanger 13 can be prevented from being made high and failure of the refrigerant sensor 16 can be prevented.

[2] Case where Humidity Sensor Is Not Used

Fig. 6 is a second flowchart showing an example of the failure prevention control according to the embodiment.
The air conditioner control unit 102 detects stoppage of a cooling operation (step S21). Next, the remote controller control unit 103 transmits instruction information to instruct the remote controller 30 to notify a user that the fan 12 will be operated. The remote controller 30 receives the instruction information and performs notification indicating that the fan 12 will be operated (step S22). For example, the remote controller 30 displays, on the display unit (not shown), a message for notification indicating that the fan will be operated. Next, the air conditioner control unit 102 intermittently operates the fan (step S23). For example, the air conditioner control unit 102 monitors a time measured by the timer 104 and operates the fan 12 for a short time (30 seconds or less) at predetermined time intervals (for example, 5 minutes). Alternatively, the air conditioner control unit 102 intermittently repeats operating the fan for the short time while increasing the interval at which the fan 12 is operated (while reducing the frequency at which the fan 12 is operated). For example, the air conditioner control unit 102 performs an operation in such a manner that the fan is operated for the short time after five minutes elapse from the stoppage of the cooling operation, the fan is operated for the short time after six minutes elapse thereafter, the fan is operated for the short time after seven minutes elapse thereafter, ... and so on. The air conditioner control unit 102 performs such operations, for example, with a time after one hour from the stoppage of the cooling operation as an upper limit. Accordingly, high-humidity air around the heat exchanger 13 is discharged, so that a humidity can be reduced and failure of the refrigerant sensor 16 can be prevented.

(Application to Heating Operation)

In the above-described example, control in which the fan 12 is operated for a short time at the time of stoppage of a cooling operation so that high-humidity air in the indoor unit 10 is exchanged with air in a room has been described. However, the failure prevention control may be applied not only to a cooling operation but also to a heating operation. For example, when there is a switch to a heating operation after a cooling operation, moisture adhering to an inner portion or the like of the heat exchanger 13 due to the cooling operation may be heated and evaporated, which may result in an increase in humidity around the refrigerant sensor 16. For prevention of failure of the refrigerant sensor 16 that is caused by such a situation, the fan 12 may be driven for a short time at the time of stoppage of the fan 12 after a heating operation (that is, at the time of stoppage of the heating operation) so that high-humidity air in the indoor unit 10 is discharged to the inside of a room. In a case where the humidity sensor 17 is used, the fan 12 can be controlled by the processes (steps S12 and subsequent steps) described with reference to Fig. 5. That is, the air conditioner control unit 102 monitors humidity measured by the humidity sensor 17, and when the humidity becomes equal to or higher than a threshold value, the air conditioner control unit 102 operates the fan 12 for a short time. In a case where the humidity sensor 17 is not used, for example, the air conditioner control unit 102 may record an operation history (for example, time history data indicating times at which a cooling operation or a heating operation is started and ended) in the storage unit 105, and the air conditioner control unit 102 may determine whether or not the current heating operation has been performed immediately after a cooling operation, and the fan 12 may be controlled by the same processes as in Fig. 6 (step S22 and subsequent steps) in a case where there is a switch to a heating operation after a cooling operation. Alternatively, the failure prevention control may be executed when the fan 12 is stopped after a heating operation regardless of whether or not the heating operation is an operation performed after a cooling operation. Accordingly, it is possible to prevent the humidity of air around the heat exchanger 13 from being made high even at the time of a heating operation and to prevent failure of the refrigerant sensor 16.
The processes in Figs. 5 and 6 are functions realized by a processor provided in the control device 100 reading out a program from the storage unit 105 and executing the program.
As described above, according to the present embodiment, when the humidity of air around the refrigerant sensor 16 is increased and an environment in which the refrigerant sensor 16 is likely to fail is created, the fan 12 is operated to discharge high-humidity air to the outside of the indoor unit. Accordingly, it is possible to prevent failure of the refrigerant sensor 16 while disposing the semiconductor-type refrigerant sensor 16, which is inexpensive, in the vicinity of the heat exchanger 13.
In addition, without departing from the spirit of the present invention, the components in the above embodiments can be appropriately replaced with known components. The technical scope of the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

An air conditioner and a control method as described in each embodiment are understood, for example, as follows.

(1) The air conditioners 1 and 1A of a first aspect include the indoor unit 10 that includes the fan 12, the heat exchanger 13 provided downstream of the fan in a direction in which air flows, and the refrigerant sensor 16 provided in the vicinity of the heat exchanger 13, the outdoor unit 20, and the control device 100, and, at the time of stoppage of a cooling operation, the control device 100 operates the fan 12 for a predetermined set time (30 seconds or less), which is a time required to discharge air in the indoor unit.

Accordingly, it is possible to prevent failure of the refrigerant sensor 16 while disposing the semiconductor-type refrigerant sensor 16, which is inexpensive, in the vicinity of the heat exchanger 13.
(2) The air conditioner 1 of a second aspect is the air conditioner 1 of (1), in which the indoor unit includes a humidity sensor provided in a vicinity of the refrigerant sensor, and at the time of the stoppage of the cooling operation, the control device operates the fan for the set time when humidity measured by the humidity sensor is equal to or higher than a threshold value.
Since the fan 12 is operated only in a situation where a high level of humidity is detected by the humidity sensor provided in the vicinity of the refrigerant sensor 16, the humidity of air around the refrigerant sensor 16 can be efficiently managed to fall within an appropriate range.
(3) The air conditioner 1A according to a third aspect is the air conditioner 1A of (1), in which, at the time of the stoppage of the cooling operation, the control device operates the fan for the set time for each time a predetermined time elapses.
Accordingly, it is possible to perform control such that the humidity of air around the refrigerant sensor 16 does not increase without providing a humidity sensor.
(4) The air conditioner 1A according to a fourth aspect is the air conditioner 1A of (1), in which, at the time of the stoppage of the cooling operation, the control device repeats operating the fan for the set time while increasing an interval at which the fan is operated.
Accordingly, it is possible to perform control such that the humidity of air around the refrigerant sensor 16 does not increase without providing a humidity sensor. The humidity in the indoor unit 10 is expected to be reduced as the fan 12 is operated and thus the interval at which the fan 12 is operated is increased so that operation of the fan 12 can be suppressed.
(5) The air conditioners 1 and 1A according to a fifth aspect are the air conditioners 1 and 1A of any one of (1) to (4), in which the vicinity of the heat exchanger is any region including the heat exchanger that is downstream of the fan in a direction in which the air flows and a discharge outlet through which air subjected to heat exchange at the heat exchanger is discharged into a room.
Since the refrigerant sensor 16 can be provided in the vicinity of a heat exchanger, it is possible to quickly detect refrigerant leakage.
(6) The air conditioners 1 and 1A according to a sixth aspect are the air conditioners 1 and 1A of any one of (1) to (5), in which the refrigerant sensor is a semiconductor-type refrigerant sensor.
Since the risk of failure can be reduced, a semiconductor-type refrigerant sensor can be used.
(7) The air conditioners 1 and 1A according to a seventh aspect are the air conditioners 1 and 1A of any one of (1) to (5), in which, at a time of stoppage of a heating operation after the cooling operation, the control device operates the fan for the set time.
It is possible to cope with not only an increase in humidity at the time of a cooling operation but also an increase in humidity at the time of a heating operation.
(8) A control method according to an eighth aspect is a control method for an air conditioner including an indoor unit that includes a fan, a heat exchanger provided downstream of the fan in a direction in which air flows, and a refrigerant sensor provided in a vicinity of the heat exchanger, and an outdoor unit, the method including operating, at a time of stoppage of a cooling operation, the fan for a predetermined set time, which is a time required to discharge air in the indoor unit.

Industrial Applicability

Reference Signs List

1, 1A: air conditioner
10, 10A: indoor unit
11, 11A: intake port
12, 12A: fan
13, 13A: heat exchanger
14, 14A: discharge outlet
15, 15A: sensor casing
16: refrigerant sensor
17: humidity sensor
20: outdoor unit
30: remote controller
100: control device
101: sensor information acquisition unit
102: air conditioner control unit
103: remote controller control unit
104: timer
105: storage unit

Claims

An air conditioner comprising:
an indoor unit that includes a fan, a heat exchanger, and a refrigerant sensor provided in a vicinity of the heat exchanger;

an outdoor unit; and

a control device,

wherein, at a time of stoppage of a cooling operation, the control device operates the fan for a predetermined set time, which is a time required to discharge air in the indoor unit.
The air conditioner according to Claim 1,
wherein the indoor unit includes a humidity sensor provided in a vicinity of the refrigerant sensor, and

at the time of the stoppage of the cooling operation, the control device operates the fan for the set time when humidity measured by the humidity sensor is equal to or higher than a threshold value.
The air conditioner according to Claim 1,
wherein, at the time of the stoppage of the cooling operation, the control device operates the fan for the set time for each time a predetermined time elapses.
The air conditioner according to Claim 1,
wherein, at the time of the stoppage of the cooling operation, the control device repeats operating the fan for the set time while increasing an interval at which the fan is operated.
The air conditioner according to Claim 1 or 2,
wherein the vicinity of the heat exchanger is any region including the heat exchanger that is downstream of the fan in a direction in which the air flows and a discharge outlet through which air subjected to heat exchange at the heat exchanger is discharged into a room.
The air conditioner according to Claim 1 or 2,
wherein the refrigerant sensor is a semiconductor-type refrigerant sensor.
The air conditioner according to Claim 1 or 2,
wherein, at a time of stoppage of a heating operation, the control device operates the fan for the set time.
A control method for an air conditioner including an indoor unit that includes a fan, a heat exchanger, and a refrigerant sensor provided in a vicinity of the heat exchanger, and an outdoor unit, the method comprising:
operating, at a time of stoppage of a cooling operation, the fan for a predetermined set time, which is a time required to discharge air in the indoor unit.