Indoor unit, air conditioner, control method, and program

Abstract

This indoor unit for an air conditioner comprises: a heat exchanger in which a refrigerant having a greater specific gravity than air and containing an odorant flows; a blower that generates an air flow that passes downward from above the heat exchanger; a discharge device that is disposed above the heat exchanger and deodorizes air by discharge; a refrigerant detection unit that is disposed below the heat exchanger and detects the concentration of the refrigerant in the air; an indoor unit housing which accommodates the heat exchanger, the blower, the discharge device, and the refrigerant detection unit and has a suction port that opens upward and a blow-out port that opens downward; and a leakage handling control unit that stops the discharge device and puts the blower in an operation state when a concentration exceeding a first threshold value is detected by the refrigerant detection unit, and performs deodorization by the discharge device while keeping the blower in the operation state when the concentration of the refrigerant is equal to or less than a second threshold value.

Description

Indoor unit, air conditioner, control method, and program

[0001] The present disclosure relates to an indoor unit, an air conditioner, a control method, and a program.

[0002] Air conditioners equipped with a discharge device inside the indoor unit are known. For example, Patent Document 1 describes an air conditioner equipped with a high-added-function device that serves as a discharge device that utilizes discharge phenomena to collect dust, disinfect, deodorize, and beautify the skin, and that prevents ignition due to discharge even if a refrigerant leaks.

[0003] JP 2013-064524 A

[0004] However, air conditioners sometimes use refrigerants containing odorants. Although adding odorants to refrigerants allows the human sense of smell to detect refrigerant leaks, the odor of the odorant can remain in the room for a long time even after the refrigerant leak has stopped, creating an unpleasant indoor environment.

[0005] The present disclosure has been made to solve the above problems, and its purpose is to provide an indoor unit, an air conditioner, a control method, and a program that can be controlled to ensure a comfortable indoor environment while ensuring safety even in the event of a refrigerant leak.

[0006] In order to solve the above problems, one aspect of the present disclosure is an indoor unit of an air conditioner, comprising: a heat exchanger through which a refrigerant having a specific gravity greater than that of air and containing an odorant flows; a blower that generates an airflow that passes from above to below the heat exchanger; a discharge device that is disposed above the heat exchanger and deodorizes the air by discharging; a refrigerant detection unit that is disposed below the heat exchanger and detects the concentration of the refrigerant contained in the air; an indoor unit housing that houses the heat exchanger, the blower, the discharge device, and the refrigerant detection unit and has an intake port that opens upward and an outlet that opens downward; and a leakage response control unit that, when the refrigerant detection unit detects a concentration that exceeds a first threshold, stops the discharge device and operates the blower, and, when the refrigerant concentration is equal to or less than a second threshold, operates the blower while deodorizing using the discharge device.

[0007] In order to solve the above problems, one aspect of the present disclosure is an air conditioner including the indoor unit described above, a refrigerant circuit through which the refrigerant circulates, and an outdoor unit.

[0008] In order to solve the above problems, one aspect of the present disclosure is a control method performed by an indoor unit of an air conditioner, the indoor unit including: a heat exchanger through which a refrigerant having a specific gravity greater than air and containing an odorant flows; a blower that generates an airflow that passes from above to below the heat exchanger; a discharge device that is arranged above the heat exchanger and that deodorizes the air by discharging; a refrigerant detection unit that is arranged below the heat exchanger and that detects the concentration of the refrigerant contained in the air; and an indoor unit housing that houses the heat exchanger, the blower, the discharge device, and the refrigerant detection unit, and has an intake port that opens upward and an outlet that opens downward, wherein a leakage response control unit of the indoor unit stops the discharge device and operates the blower when the refrigerant detection unit detects a concentration that exceeds a first threshold, and when the refrigerant concentration is equal to or less than a second threshold, the control method

[0009] In order to solve the above problems, one aspect of the present disclosure is an indoor unit of an air conditioner, the indoor unit including: a heat exchanger through which a refrigerant having a specific gravity greater than air and containing an odorant flows; a blower that generates an airflow that passes from above to below the heat exchanger; a discharge device that is disposed above the heat exchanger and deodorizes the air by discharging; a refrigerant detection unit that is disposed below the heat exchanger and detects the concentration of the refrigerant contained in the air; and an indoor unit housing that houses the heat exchanger, the blower, the discharge device, and the refrigerant detection unit, and has an intake port that opens upward and an outlet that opens downward. The indoor unit includes a computer that, when the refrigerant detection unit detects a concentration that exceeds a first threshold, stops the discharge device and operates the blower, and operates the blower when the refrigerant concentration is equal to or less than a second threshold.

[0010] According to the present disclosure, even in the event of a refrigerant leak, it is possible to control the indoor environment to be comfortable while ensuring safety.

[0011] 1 is a diagram illustrating an example of the configuration of an air conditioner in an embodiment; FIG. 2 is a perspective view of an indoor unit in a first embodiment; FIG. 3 is a cross-sectional view of an indoor unit in the first embodiment; FIG. 4 is a flowchart illustrating the flow of processing performed by the indoor unit in the first embodiment; FIG. 5 is a perspective view of an indoor unit in a second embodiment; FIG. 6 is a cross-sectional view of an indoor unit in the second embodiment; and FIG. 7 is a flowchart illustrating the flow of processing performed by the indoor unit in the second embodiment.

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the scope of the present disclosure is not limited to the following embodiments and can be modified as desired within the scope of the technical concept of the present disclosure. In addition, in the following drawings, the scale and number of each structure may differ from the scale and number of the actual structure in order to make each configuration easier to understand.

[0013] The drawings also show X, Y, and Z axes as appropriate. The X axis indicates the front-to-rear direction of the indoor unit 20 in the air conditioner 100 of the embodiment described below. The Y axis indicates the left-to-right direction of the indoor unit 20. The Z axis indicates the vertical direction. The front-to-rear direction, left-to-right direction, and vertical direction are perpendicular to one another. The side of the front-to-rear direction toward which the X-axis arrow points (+X side) is the front side, and the side of the front-to-rear direction opposite to the side of the X-axis arrow (-X side) is the rear side. The side of the left-to-right direction toward which the Y-axis arrow points (+Y side) is the left side, and the side of the left-to-right direction opposite to the side of the Y-axis arrow (-Y side) is the right side. The side of the vertical direction toward which the Z-axis arrow points (+Z side) is the upper side, and the side of the vertical direction opposite to the side of the Z-axis arrow (-Z side) is the lower side.

[0014] <Common to all embodiments> Fig. 1 is a schematic diagram showing the overall configuration of an air conditioner 100 common to all embodiments. As shown in Fig. 1, the air conditioner 100 includes an outdoor unit 10, an indoor unit 20, and a circulation path section 18. The outdoor unit 10 is disposed outdoors. The indoor unit 20 is disposed indoors. The outdoor unit 10 and the indoor unit 20 are connected to each other by the circulation path section 18 through which a refrigerant 19 circulates. Examples of the refrigerant 19 include a fluorine-based refrigerant or a hydrocarbon-based refrigerant with a low global warming potential (GWP).

[0015] As refrigerants with low GWP values, hydrocarbons with 1 to 4 carbon atoms, such as R-290 (propane), R-1270 (propylene), R-600 (butane), and R-600a (isobutane), are being considered. Hydrocarbons with 1 to 4 carbon atoms have GWP values ​​even lower than saturated fluorinated hydrocarbon compounds (hydrofluorocarbons), which are refrigerants with relatively low GWP values.

[0016] Some refrigerants with low GWP are flammable. For example, in the international standard ISO-817, which defines the safety grade of refrigerants, R-32 (difluoromethane), a type of hydrofluorocarbon, is registered as slightly flammable (Class 2L), while R-290, R-1270, R-600, and R-600a are registered as highly flammable (Class 3). If a flammable refrigerant leaks inside the indoor unit 20, care must be taken to prevent ignition. Because refrigerant leaking inside the indoor unit 20 may leak into the room, it is necessary to ensure that people inside the room can quickly detect the refrigerant leak. For this reason, an odorant is blended into the refrigerant 19 of this embodiment.

[0017] The odorant blended into the refrigerant 19 may be, for example, a sulfur-based odorant. Examples of sulfur-based odorants include mercaptans, sulfides, and thiophenes. These sulfur-based odorants are compounds that have been used in fuel gases and have an unpleasant odor. Alternatively, an odorant that does not contain sulfur may be blended into the refrigerant 19. Examples of sulfur-free odorants include cyclohexene, acrylic esters, ammonia, amines, pyrazines, and norbornenes. In addition to these sulfur-free odorants, compounds with distinctive odors may also be included as odorants.

[0018] The air conditioner 100 is capable of adjusting the temperature of the air in the room by exchanging heat between the refrigerant 19 flowing in the circulation path portion 18 and the air in the room where the indoor unit 20 is located.

[0019] The outdoor unit 10 has an outdoor unit housing 11, a compressor 12, a heat exchanger 13, a flow rate adjustment valve 14, a blower 15, a four-way valve 16, and an air conditioning control unit 17. The outdoor unit housing 11 houses the compressor 12, the heat exchanger 13, the flow rate adjustment valve 14, the blower 15, the four-way valve 16, and the air conditioning control unit 17.

[0020] The compressor 12, the heat exchanger 13, the flow rate adjustment valve 14, and the four-way valve 16 are provided in a portion of the circulation path 18 that is located inside the outdoor unit housing 11. The compressor 12, the heat exchanger 13, the flow rate adjustment valve 14, and the four-way valve 16 are connected by a portion of the circulation path 18 that is located inside the outdoor unit housing 11.

[0021] The four-way valve 16 is provided in a portion of the circulation path section 18 that is connected to the discharge side of the compressor 12. The four-way valve 16 can reverse the direction of the refrigerant 19 flowing through the circulation path section 18 by switching a portion of the path of the circulation path section 18. When the path connected by the four-way valve 16 is the path shown by the solid line on the four-way valve 16 in Fig. 1, the refrigerant 19 flows through the circulation path section 18 in the direction shown by the solid arrow in Fig. 1. On the other hand, when the path connected by the four-way valve 16 is the path shown by the dashed line on the four-way valve 16 in Fig. 1, the refrigerant 19 flows through the circulation path section 18 in the direction shown by the dashed arrow in Fig. 1.

[0022] The indoor unit 20 has an indoor unit housing 21, a heat exchanger 22, a blower 23, and a leakage response control unit 24. The indoor unit 20 is capable of cooling operation to cool the air in the room where the indoor unit 20 is located, and heating operation to warm the air in the room where the indoor unit 20 is located.

[0023] When the indoor unit 20 is in cooling operation, the refrigerant 19 flowing in the circulation path portion 18 flows in the direction shown by the solid arrow in Fig. 1. In other words, when the indoor unit 20 is in cooling operation, the refrigerant 19 flowing in the circulation path portion 18 circulates through the compressor 12, the heat exchanger 13 of the outdoor unit 10, the flow control valve 14, and the heat exchanger 22 of the indoor unit 20 in that order, before returning to the compressor 12. During cooling operation, the heat exchanger 13 in the outdoor unit 10 functions as a condenser, and the heat exchanger 22 in the indoor unit 20 functions as an evaporator.

[0024] On the other hand, when the indoor unit 20 is in heating operation, the refrigerant 19 flowing in the circulation path portion 18 flows in the direction shown by the dashed line in Fig. 1. In other words, when the indoor unit 20 is in heating operation, the refrigerant 19 flowing in the circulation path portion 18 circulates through the compressor 12, the heat exchanger 22 of the indoor unit 20, the flow control valve 14, and the heat exchanger 13 of the outdoor unit 10 in that order, before returning to the compressor 12. In heating operation, the heat exchanger 13 in the outdoor unit 10 functions as an evaporator, and the heat exchanger 22 in the indoor unit 20 functions as a condenser.

[0025] <First embodiment> Fig. 2 is a perspective view of the indoor unit 20 in the first embodiment. Fig. 3 is a cross-sectional view of the indoor unit 20 in the first embodiment. As shown in the examples of Fig. 2 and Fig. 3, the indoor unit 20 is, for example, a wall-mounted indoor unit that is fixed to a wall surface inside a room.

[0026] As shown in Fig. 2, the indoor unit housing 21 has an intake port 200 that opens upward, an outlet port 202 that opens downward, a notification unit 204, a light-emitting unit 206, and a refrigerant detection unit 208. As shown in Fig. 3, the indoor unit housing 21 also has a discharge device 210, upper and lower airflow direction vanes 212 (upper and lower airflow direction vanes 212A, 212B), and left and right airflow direction vanes 214.

[0027] 1 to 3, the indoor unit housing 21 houses therein a heat exchanger 22, a blower 23, a leakage response control unit 24, a refrigerant detection unit 208, a discharge device 210, upper and lower airflow direction vanes 212, and left and right airflow direction vanes 214. In addition, as shown in FIG. 2, a notification unit 204 and a light-emitting unit 206 are provided on the front surface of the indoor unit housing 21.

[0028] The heat exchanger 22 is provided in the circulation path 18 and exchanges heat between the refrigerant 19 flowing inside the circulation path 18 and the indoor air AF drawn into the indoor unit housing 21. As shown in FIG. 3 , the heat exchanger 22 is disposed surrounding the blower 23 in the air path extending from the air inlet 200 to the air outlet 202. The air AF drawn into the indoor unit housing 21 through the air inlet 200 passes through the heat exchanger 22 and exchanges heat with the refrigerant 19. The air AF after heat exchange is blown out of the indoor unit 20 through the air outlet 202. As a result, the air AF that has exchanged heat with the refrigerant 19 by the heat exchanger 22 is blown into the room through the air outlet 202. The heat exchanger 22 may have any structure as long as it is capable of exchanging heat between the refrigerant 19 and the indoor air AF.

[0029] As shown in Fig. 3 , the blower 23 rotates in the direction of the symbol D to draw in indoor air AF through the air inlet 200 and blow out the drawn air AF from the air outlet 202. The blower 23 is, for example, a cross-flow fan. Note that the blower 23 may be any type of blower.

[0030] The leakage response control unit 24 is connected to be able to communicate with the notification unit 204, the light emitting unit 206, the refrigerant detection unit 208, the discharge device 210, the upper and lower airflow direction vanes 212, and the left and right airflow direction vanes 214. The leakage response control unit 24 performs control to respond to the leakage when the refrigerant 19 leaks into the indoor unit housing 21. Details of the control to respond to the leakage performed by the leakage response control unit 24 will be described later.

[0031] The alarm unit 204 is an alarm element that outputs sound to notify of a leak of the refrigerant 19. The alarm unit 204 includes a sound output device such as a speaker. The alarm unit 204 outputs an alarm sound or voice in accordance with the control of the leakage response control unit 24.

[0032] The light-emitting unit 206 is a light-emitting element that emits light to notify of leakage of the refrigerant 19. The light-emitting unit 206 includes a light-emitting body such as an LED (Light Emitting Diode). The light-emitting unit 206 emits light in accordance with the control of the leakage response control unit 24.

[0033] The refrigerant detection unit 208 detects the concentration of refrigerant 19 contained in the air. As shown in Fig. 3, the refrigerant detection unit 208 is disposed below the heat exchanger 22. This is because the density of refrigerant 19 in a gaseous state is greater than the density of air, and if refrigerant 19 leaks inside the indoor unit housing 21, the leaked refrigerant 19 is thought to fall downward.

[0034] The refrigerant detection unit 208 detects the concentration of refrigerant 19. For example, the refrigerant detection unit 208 is a semiconductor-type refrigerant sensor. When refrigerant 19 leaked into the indoor unit housing 21 comes into contact with the refrigerant detection unit 208, the resistance value of the semiconductor changes. This change in resistance allows the refrigerant detection unit 208 to detect the refrigerant 19. Note that the refrigerant detection unit 208 may have any structure as long as it can detect the concentration of refrigerant 19, and may be, for example, an infrared-type refrigerant sensor. The refrigerant detection unit 208 transmits a detection signal indicating the detected concentration of refrigerant 19 to the leak response control unit 24.

[0035] The discharge device 210 is a device that purifies the air in a room by electrical discharge. In this embodiment, the discharge device 210 is used as a deodorizing device that eliminates odors in the room, particularly odors caused by odorant due to leakage of the refrigerant 19. The discharge device 210 may also be used as an electrostatic precipitator. As shown in FIG. 3 , at least a portion of the air AF drawn into the air intake 200 by driving the blower 23 passes through the discharge device 210. The air AF is purified by passing through the discharge device 210. By continuing to operate the indoor unit 20, the air in the room can be purified.

[0036] For example, a discharge unit having a wire portion and an electrode portion is provided above the discharge device 210 so as to be exposed. An opening is provided below the discharge device 210. A portion of the air drawn into the suction port 200 flows into the discharge unit, passes through the discharge unit in the vertical direction Z, and is discharged to the outside of the discharge device 210 through the opening. When a current is passed through the wire portion of the discharge unit, a discharge occurs between the wire portion and the electrode portion. This discharge can inactivate bacteria, viruses, and the like contained in the air passing through the discharge unit, thereby purifying the air.

[0037] As shown in Fig. 3, the discharge device 210 is disposed above the heat exchanger 22. When the air conditioner 100 is in cooling operation, the cold air may cause condensation inside the indoor unit housing 21. This is to prevent water droplets caused by this condensation from causing a short circuit in the discharge section of the discharge device 210, which could lead to breakdown.

[0038] 3, the vertical airflow direction vane 212 is rotatably attached to the air outlet 202. The vertical airflow direction vane 212 can change the direction of air blown out from the air outlet 202 in the vertical direction.

[0039] 3, the left-right air deflector 214 is rotatably attached to the back of the air outlet 202. The left-right air deflector 214 can change the direction of air blown out from the air outlet 202 to the left or right.

[0040] Here, details of the control performed by the leakage response control unit 24 to respond to leakage will be described using Fig. 4. Fig. 4 is a flowchart showing the flow of processing performed by the indoor unit 20 in the first embodiment. This flow assumes that the air conditioner 100 is in operation.

[0041] The leak response control unit 24 of the indoor unit 20 determines whether refrigerant 19 with a concentration exceeding the first threshold has been detected (step S10). The leak response control unit 24 receives a detection signal from the refrigerant detection unit 208 and determines whether refrigerant 19 with a concentration exceeding the first threshold has been detected based on the concentration indicated in the received detection signal. The first threshold is, for example, a value obtained by subtracting a certain margin from the flammable concentration of refrigerant 19. This makes it possible to take measures such as shutting off refrigerant 19 and ventilating the room before the refrigerant 19 exceeds the flammable concentration.

[0042] When a concentration of refrigerant 19 exceeding the first threshold is detected, the leak response control unit 24 issues a warning of the refrigerant 19 leak (step S11). For example, the leak response control unit 24 notifies the refrigerant 19 leak by causing the notification unit 204 to output a warning sound such as an alarm sound. The leak response control unit 24 may also cause the notification unit 204 to output a voice message such as, "Please open a window to ventilate." The leak response control unit 24 also notifies the refrigerant 19 leak by causing the light-emitting unit 206 to emit light. The leak response control unit 24 may emit light of a specific color, such as red, indicating a refrigerant 19 leak, or may blink the light to attract attention. The leak response control unit 24 may control the alarm sound from the notification unit 204 and the blinking light from the light-emitting unit 206 to be synchronized.

[0043] The leakage response control unit 24 stops the compressor 12 and the discharge device 210 (step S12). By stopping the compressor 12, the leakage response control unit 24 stops the circulation of the refrigerant 19 flowing inside the circulation path unit 18, thereby suppressing further leakage of the refrigerant 19. The leakage response control unit 24 stops the discharge device 210 to prevent discharge from occurring. This is because if refrigerant 19 with a flammable concentration comes into contact with the discharge from the discharge device 210, the refrigerant 19 may ignite.

[0044] The leak response control unit 24 executes the refrigerant stirring mode. The refrigerant stirring mode is an operating mode that stirs the leaked refrigerant 19 to prevent the creation of areas with high refrigerant 19 concentrations. In the refrigerant stirring mode, the leak response control unit 24 drives the blower 23 at its maximum rotation speed (step S13). By driving the blower 23, the refrigerant 19 is discharged from the indoor unit housing 21, reducing the concentration of refrigerant 19 in the indoor unit housing 21. Furthermore, by maximizing the rotation speed of the blower 23, the refrigerant 19 is discharged farther from the location where the indoor unit housing 21 is installed, thereby preventing the concentration of refrigerant 19 in the room from increasing. Furthermore, it is desirable for the leak response control unit 24 to continuously operate the blower 23 in the refrigerant stirring mode. By continuously operating the blower 23, the refrigerant 19 can be uniformly dispersed.

[0045] In this embodiment, the refrigerant 19 contains an odorant, and when a leak of the refrigerant 19 is detected and the blower 23 is driven, the odor of the odorant is released into the room. This causes an unpleasant odor to waft through the room, deteriorating the indoor environment. The odorant is added to the refrigerant 19 to enable the human sense of smell to quickly detect a refrigerant leak, so it is necessary to release the odor of the odorant in the event of a refrigerant leak. However, if an unpleasant odor continues to remain in the room even after the refrigerant leak has stopped, it is uncomfortable for users in the room.

[0046] As a countermeasure, the indoor unit 20 of this embodiment ensures safety by executing the refrigerant agitation mode described above, and then transitions to the deodorization mode. The deodorization mode is an operating mode that deodorizes the room while continuing to operate the blower 23. Specifically, after executing the refrigerant agitation mode corresponding to step S13, the leakage response control unit 24 performs deodorization using the discharge device 210 on the condition that the refrigerant concentration is equal to or lower than a second threshold value. The second threshold value is, for example, a value that is sufficiently lower than the flammable concentration of the refrigerant 19 and is equal to or higher than the lower limit concentration at which the odorant blended in the refrigerant 19 can be detected by humans. This allows deodorization using the discharge device 210 to be performed while ensuring safety.

[0047] The leak response control unit 24 determines whether the concentration of the refrigerant 19 is equal to or less than the second threshold value (step S14). The leak response control unit 24 receives a detection signal from the refrigerant detection unit 208 and determines whether the concentration of the refrigerant 19 is equal to or less than the second threshold value based on the concentration indicated in the received detection signal. If the concentration of the refrigerant 19 is not equal to or less than the second threshold value (step S14, No), the leak response control unit 24 returns to step S13 and continues to drive the blower 23 at the maximum rotation speed until the concentration of the refrigerant 19 becomes equal to or less than the second threshold value, thereby executing the refrigerant agitation mode.

[0048] If the concentration of the refrigerant 19 is equal to or lower than the second threshold (step S14, No), the leak response control unit 24 executes the deodorization mode. The leak response control unit 24 intermittently operates the blower 23 (step S15). The interval for intermittently operating the blower 23 may be set arbitrarily, for example, every 2 to 3 seconds. By intermittently operating the blower 23, the leak response control unit 24 generates a pulsating airflow path in the room. As a result, for example, when the blower 23 is driven, odors in the room can be stirred up, and when the blower 23 is stopped, the stirred-up odors can be lifted and guided upward. The odors guided upward and floating near the air intake 200 can then be taken into the indoor unit 20 the next time the blower 23 is driven. While the blower 23 is intermittently operated in step S15, the leak response control unit 24 may control the vertical airflow direction flap 212 to face downward. By discharging downward air from the outlet 202, odors can be easily released.

[0049] The leakage response control unit 24 turns on the power supply of the discharge device 210 (step S15), which drives the discharge device 210 and deodorizes the air passing through the discharge device 210.

[0050] The leakage control unit 24 also controls the swing of the vertical air deflector 212 and the horizontal air deflector 214. The leakage control unit 24 repeatedly rotates the vertical air deflector 212 in the up and down direction. The leakage control unit 24 also repeatedly rotates the horizontal air deflector 214 in the left and right direction. As a result, when the blower 23 is next driven in intermittent operation, odors floating around the air inlet 200 can be taken in through the air inlet 200, while the air that has passed through the discharge device 210 and been deodorized can be evenly discharged into the room.

[0051] The leakage response control unit 24 determines whether the concentration of the refrigerant 19 is equal to or less than the second threshold value (step S18). The method by which the leakage response control unit 24 determines whether the concentration of the refrigerant 19 is equal to or less than the second threshold value is the same as that used in step S14. If the concentration of the refrigerant 19 is not equal to or less than the second threshold value (step S18, No), the leakage response control unit 24 stops the discharge device 210 (step S19), returns to step S13, and executes the refrigerant stirring mode.

[0052] If the concentration of the refrigerant 19 is equal to or lower than the second threshold value (Yes in step S18), the leakage response control unit 24 determines whether or not a service technician has taken action (step S20). If a service technician has taken action (Yes in step S20), the leakage response control unit 24 ends the process.

[0053] A service technician is a worker who, when a refrigerant 19 leak is detected, checks the leak status and takes necessary measures, such as replacing parts, depending on the leak status to ensure safe operation of the air conditioner 100. For example, the remote control that controls the operation of the indoor unit 20 is designed to send a maintenance signal through a specific input operation. Once the service technician confirms that the air conditioner 100 can be operated safely, he or she operates the remote control to send a specific maintenance signal to the indoor unit 20. This allows the leak response control unit 24 of the indoor unit 20 to detect that a service technician has performed the repair. Alternatively, the outdoor unit 10 is provided with a panel that can only be opened and closed using a special screwdriver, and a maintenance operation board is housed inside the panel. Once the service technician confirms that the air conditioner 100 can be operated safely, he or she opens the panel using the special screwdriver and presses a specific button on the operation board. This allows the leak response control unit 24 of the indoor unit 20 to detect that a service technician has performed the repair.

[0054] If no action has been taken by a service technician (No in step S20), the leakage response control unit 24 controls the blower 23 of the indoor unit 20 not to stop. This is to prepare for an unexpected situation such as further leakage of refrigerant 19. Specifically, the leakage response control unit 24 returns to step S15 and executes the deodorization mode.

[0055] As described above, the indoor unit 20 according to the first embodiment includes the heat exchanger 22, the blower 23, the discharge device 210, the refrigerant detection unit 208, the indoor unit housing 21, and the leakage response control unit 24. The heat exchanger 22 is a heat exchanger through which the refrigerant 19, which has a specific gravity greater than that of air and in which an odorant is sealed, flows. The blower 23 generates an airflow that passes from above to below the heat exchanger 22. The discharge device 210 is disposed above the heat exchanger 22 and deodorizes the air by discharge. The discharge device 210 is disposed below the heat exchanger 22 and detects the concentration of the refrigerant 19 contained in the air. The indoor unit housing 21 houses the heat exchanger 22, the blower 23, the discharge device 210, and the refrigerant detection unit 208, and has an intake port 200 that opens upward and an outlet port 202 that opens downward. When refrigerant detection unit 208 detects a concentration exceeding the first threshold, leakage response control unit 24 stops discharge device 210 and operates blower 23. When the concentration of refrigerant 19 is equal to or lower than the second threshold, leakage response control unit 24 performs deodorization using discharge device 210.

[0056] As a result, the indoor unit 20 according to the first embodiment can respond to a leak of the refrigerant 19 by preventing the refrigerant concentration from increasing, that is, by executing the refrigerant stirring mode, the refrigerant concentration in the air can be prevented from increasing, thereby ensuring safety. Furthermore, deodorization by discharge can be performed by executing the deodorization mode, provided that the concentration of the refrigerant 19 is below the second threshold and there is no possibility of ignition. Therefore, even in the event of a refrigerant leak, control can be performed to ensure a comfortable indoor environment while ensuring safety.

[0057] Furthermore, in the indoor unit 20 according to the first embodiment, when the concentration of the refrigerant 19 exceeds the first threshold value, the leakage response control unit 24 maximizes the rotation speed of the blower 23 and causes it to operate continuously. This allows the indoor unit 20 according to the first embodiment to diffuse the refrigerant 19 that has leaked into the indoor unit housing 21 as far as possible, and prevents the concentration of the refrigerant 19 from increasing.

[0058] Furthermore, in the indoor unit 20 according to the first embodiment, if the concentration of the refrigerant 19 exceeds the first threshold value after deodorization by the discharge device 210, the leakage response control unit 24 maximizes the rotation speed of the blower 23 and causes it to operate continuously. This allows the indoor unit 20 according to the first embodiment to alternate between the deodorizing mode and the refrigerant stirring mode as necessary, depending on the refrigerant concentration. Therefore, even in situations where the refrigerant concentration is unevenly distributed in the room, control can be performed to ensure a comfortable indoor environment while ensuring safety.

[0059] Furthermore, in the indoor unit 20 according to the first embodiment, when deodorizing using the discharge device 210, the leakage response control unit 24 performs deodorization using the discharge device 210 while intermittently operating the blower 23. As a result, in the indoor unit 20 according to the first embodiment, by intermittently operating the blower 23, odors remaining in the room can be stirred up and guided to the periphery of the discharge device 210, and then deodorization can be performed, thereby enabling effective deodorization.

[0060] <Second embodiment> Fig. 5 is a perspective view of the indoor unit 20 in a second embodiment. Fig. 6 is a cross-sectional view of the indoor unit 20 in the second embodiment. In this embodiment, configurations that differ from the first embodiment described above will be mainly described, and configurations that are similar to those in the first embodiment will be assigned the same reference numerals and descriptions thereof will be omitted.

[0061] The indoor unit 20 is equipped with an odor detection unit 216. The odor detection unit 216 is a device that detects odors. The odor detection unit 216 detects odors in the air and outputs a detection signal corresponding to the strength of the detected odor. The odor detection unit 216 may have any structure as long as it can detect odors in the air, particularly the strength of odors caused by odorants. The odor detection unit 216 transmits a detection signal indicating the strength of the detected odor to the leak response control unit 24.

[0062] 5 and 6, the odor detection unit 216 is disposed, for example, below the heat exchanger 22. This is to enable accurate detection of odors from the odorant caused by leakage of the refrigerant 19. However, this is not limiting, and the odor detection unit 216 may be disposed above the heat exchanger 22, for example, near the discharge device 210. By disposing the odor detection unit 216 near the discharge device 210, odors in the room can be detected accurately.

[0063] Figure 7 is a flowchart showing the flow of processing performed by the indoor unit 20 in the second embodiment. This flow assumes that the air conditioner 100 is in operation, as in Figure 4. The processing shown in steps S110 to S119 in Figure 7 is the same as the processing shown in steps S10 to S19 in Figure 4, and therefore a description thereof will be omitted.

[0064] If the concentration of refrigerant 19 is equal to or lower than the second threshold value (Yes in step S118), the leak response control unit 24 of the indoor unit 20 determines whether the odor level is equal to or lower than the uncomfortable level (step S120). The leak response control unit 24 receives a detection signal from the odor detection unit 216 and determines whether the odor level is equal to or lower than the uncomfortable level based on the odor intensity indicated in the received detection signal. The uncomfortable level is, for example, the lower limit of the odor that makes humans feel uncomfortable.

[0065] If the odor level exceeds the discomfort level (No at step S120), the leakage response control unit 24 returns to step S15 and executes the deodorization mode.

[0066] If the odor level is below the discomfort level (step S120, Yes), the leakage response control unit 24 stops the discharge device 210 (step S121). The process shown in step S122 is similar to the process shown in step S20 of FIG. 4, and therefore its description will be omitted. If no action has been taken by a service technician (step S122, No), the leakage response control unit 24 returns to step S120 and continues monitoring the odor level. If the odor level exceeds the discomfort level, the process returns to step S15 and the deodorization mode is executed. This allows deodorization even if an odor returns after a while after it has disappeared.

[0067] As described above, the indoor unit 20 according to the second embodiment further includes an odor detection unit 216 that detects odors. After deodorization by the discharge device 210, if the concentration of the refrigerant 19 is equal to or lower than the second threshold and the odor intensity detected by the odor detection unit 216 is equal to or lower than the unpleasant level, the leakage response control unit 24 stops the discharge device 210 while keeping the blower 23 in operation. This allows the indoor unit 20 according to the second embodiment to stop the discharge device 210 once the odor has been deodorized to a level that is not unpleasant to humans, thereby reducing power consumption. Furthermore, by keeping the blower 23 in operation even when the discharge device 210 is stopped, it is possible to prepare for unexpected situations until a service technician checks the status of the leak.

[0068] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the configurations of the above-described embodiments, and the following configurations and methods may also be adopted.

[0069] In the processing shown in steps S15 to S17 (steps S115 to S117) corresponding to the deodorizing mode, the leakage response control unit 24 may repeatedly execute the processing shown in steps S15 to S17 multiple times while changing the combination of the rotation speed of the blower 23 and the direction of the vertical airflow direction flap 212. For example, by repeatedly executing the processing while gradually increasing the rotation speed of the blower 23 and gradually changing the direction of the air blown out of the air outlet 202 from downward to upward, it is possible to gradually deodorize the room from areas very close to the indoor unit housing 21 to areas far away.

[0070] For example, the rotation speed of the blower 23 can be controlled in three stages: maximum, normal, and minimum. The leakage response control unit 24 first performs deodorization using the discharge device 210 by setting the rotation speed of the blower 23 to the minimum and orienting the vertical airflow direction flap 212 downward (in the -Z direction). This deodorizes an area in the room that is very close to the indoor unit housing 21. Next, the rotation speed of the blower 23 is set to the normal speed and the direction of the vertical airflow direction flap 212 is moved forward (in the +X direction) by approximately 10 degrees, so that air is blown out in a direction 10 degrees in the +X direction relative to the -Z axis in the ZX plane. This deodorizes an area in the room that is slightly away from the indoor unit housing 21. Furthermore, the rotation speed of the blower 23 is increased to the maximum, and the direction of the vertical airflow direction vanes 212 is moved forward (in the +X direction) by another 20 degrees or so, so that air is blown out in a direction of 30 degrees in the +X direction from the -Z axis on the ZX plane, thereby deodorizing the discharge device 210. This allows deodorization of areas in the room that are far away from the indoor unit housing 21.

[0071] The leakage response control unit 24 may change the manner in which the deodorizing mode is executed depending on the time of day when the leakage of the refrigerant 19 occurred, the time period, and environmental conditions such as temperature and humidity.

[0072] The leak response control unit 24 of the indoor unit 20 described above has an internal computer system. The processing steps described above are stored in the form of a program on a computer-readable recording medium, and the computer reads and executes this program to perform the above processing. Here, computer-readable recording medium refers to a magnetic disk, magneto-optical disk, CD-ROM, DVD-ROM, semiconductor memory, etc. Alternatively, the computer program may be distributed to a computer via a communication line, and the computer that receives the program may execute the program.

[0073] The configurations and methods described in this specification can be combined as appropriate within the scope of not contradicting each other.

[0074] 20... Indoor unit, 21... Indoor unit housing, 22... Heat exchanger, 23... Blower, 24... Leakage response control unit, 200... Intake port, 202... Outlet port, 204... Notification unit, 206... Light-emitting unit, 208... Refrigerant detection unit, 210... Discharge device, 216... Odor detection unit, 100... Air conditioner, AF... Air

Claims

1. An indoor unit for an air conditioner, comprising: a heat exchanger through which a refrigerant having a specific gravity greater than air and containing an odorant flows; a blower that generates an airflow that passes from above to below the heat exchanger; a discharge device that is located above the heat exchanger and deodorizes the air by discharging; a refrigerant detection unit that is located below the heat exchanger and detects the concentration of the refrigerant contained in the air; an indoor unit housing that houses the heat exchanger, the blower, the discharge device, and the refrigerant detection unit, and has an intake port that opens upward and an outlet that opens downward; and a leakage response control unit that, when the refrigerant detection unit detects a concentration that exceeds a first threshold, stops the discharge device and operates the blower, and, when the refrigerant concentration is equal to or less than a second threshold, performs deodorization using the discharge device while keeping the blower in operation.

2. The indoor unit described in claim 1, wherein the leakage response control unit, when the concentration of the refrigerant exceeds the first threshold value, operates the blower at its maximum rotation speed continuously, and when the concentration of the refrigerant is equal to or lower than the second threshold value after operating the blower at its maximum rotation speed continuously, performs deodorization using the discharge device.

3. An indoor unit as described in claim 1 or claim 2, wherein if the concentration of the refrigerant exceeds the second threshold value after deodorization by the discharge device, the leakage response control unit stops the discharge device and maximizes the rotation speed of the blower to operate it continuously.

4. The indoor unit according to any one of claims 1 to 3, wherein when deodorizing using the discharge device, the leakage response control unit performs deodorization using the discharge device while intermittently operating the blower.

5. An indoor unit as described in any one of claims 1 to 4, further comprising an odor detection unit housed in the indoor unit casing and detecting the strength of the odor, wherein the leakage response control unit stops the discharge device while maintaining the blower in operation if the concentration of the refrigerant is below the second threshold value after deodorization by the discharge device and the odor strength detected by the odor detection unit is below an uncomfortable level.

6. An air conditioner comprising: an indoor unit according to any one of claims 1 to 5; a refrigerant circuit through which the refrigerant circulates; and an outdoor unit.

7. A control method for an indoor unit of an air conditioner comprising: a heat exchanger through which a refrigerant with a specific gravity greater than air and containing an odorant flows; a blower that generates an airflow that passes from above to below the heat exchanger; a discharge device that is arranged above the heat exchanger and deodorizes the air by discharge; a refrigerant detection unit that is arranged below the heat exchanger and detects the concentration of the refrigerant contained in the air; and an indoor unit casing that houses the heat exchanger, the blower, the discharge device, and the refrigerant detection unit and has an intake port that opens upward and an outlet that opens downward, wherein a leakage response control unit of the indoor unit stops the discharge device and operates the blower when the refrigerant detection unit detects a concentration that exceeds a first threshold, and operates the blower while deodorizing using the discharge device when the refrigerant concentration is equal to or less than a second threshold.

8. An indoor unit of an air conditioner, comprising: a heat exchanger through which a refrigerant having a specific gravity greater than air and containing an odorant flows; a blower that generates an airflow that passes from above to below the heat exchanger; a discharge device that is located above the heat exchanger and deodorizes the air by discharging; a refrigerant detection unit that is located below the heat exchanger and detects the concentration of the refrigerant contained in the air; and an indoor unit casing that houses the heat exchanger, the blower, the discharge device, and the refrigerant detection unit and has an intake port that opens upward and an outlet that opens downward, the program causing a leakage response control unit, which is a computer, to stop the discharge device and operate the blower when the refrigerant detection unit detects a concentration that exceeds a first threshold, and to operate the blower while deodorizing using the discharge device when the refrigerant concentration is equal to or less than a second threshold.

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