air conditioner

Abstract

This allows us to provide an air conditioner that offers improved safety when using flammable refrigerants. [Solution] The air conditioner of this disclosure is an air conditioner that uses a flammable refrigerant and comprises an indoor heat exchanger that exchanges heat with indoor air, an air filter through which indoor air from the room toward the indoor heat exchanger passes, a cleaning device for cleaning the air filter, and a control unit that controls the cleaning device, wherein the control unit drives the cleaning device to perform filter cleaning to remove dust adhering to the air filter.

Description

Technical Field

[0007] ,

[0001] The present disclosure relates to an air conditioner.

Background Art

[0002] An air conditioner is provided with a filter for collecting dust in the sucked air. When the filter is clogged with the dust adhering to it, the ventilation resistance increases and the performance of the air conditioner decreases. Therefore, an air conditioner having a cleaning function for removing the dust adhering to the filter has been developed.

[0003] For example, the air conditioner described in Patent Document 1 includes a filter for collecting dust in the sucked air, a cleaning mechanism for removing the dust collected by the filter, and a control unit for controlling the drive of the cleaning mechanism.

Prior Art Documents

Patent Documents

[0004] ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​ A cleaning device for cleaning air filters, A control unit that controls the cleaning device, Equipped with, The control unit drives the cleaning device to perform filter cleaning, which removes dust adhering to the air filter. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide an air conditioner that improves safety when using flammable refrigerants. [Brief explanation of the drawing]

[0009] [Figure 1] Schematic diagram of an air conditioner according to Embodiment 1 of this disclosure [Figure 2] Figure 1 is a schematic diagram showing an enlarged view of the indoor unit of the air conditioner. [Figure 3] Block diagram showing the internal configuration of the air conditioner in Figure 1. [Figure 4] Timing chart showing filter cleaning control [Figure 5] Timing chart showing filter cleaning control when a signal to interrupt filter cleaning is received. [Figure 6] Timing chart showing the execution status of filter cleaning in an air conditioner according to a modified example 1 of Embodiment 1. [Figure 7] Schematic diagram showing the indoor unit of an air conditioner according to Embodiment 2 [Figure 8] Schematic diagram of region R1 enlarged in Figure 7. [Figure 9] Schematic diagram showing the indoor unit of an air conditioner according to a modified example 1 of Embodiment 2. [Figure 10] A schematic diagram showing a dust box according to a modified example 2 of Embodiment 2. [Figure 11] A schematic diagram showing a dust box according to a modified example 2 of Embodiment 2. [Figure 12] Timing chart showing the control of filter cleaning when a signal to interrupt filter cleaning is received in the air conditioner according to Embodiment 3.

Mode for Carrying Out the Invention

[0010] (Background Leading to the Present Disclosure) In recent years, from the perspective of preventing global warming, it has been required to use a refrigerant with a low global warming potential (GWP). As a refrigerant with a small GWP, for example, the use of propane (R290) etc. has been considered. Since refrigerants such as propane are flammable, for example, when they leak in the indoor unit of an air conditioner, it is also conceivable that the refrigerant catches fire, and it is important to improve safety.

[0011] In an air conditioner using a flammable refrigerant, if dust adheres to the air filter, there is a risk of quasi-combustion when the refrigerant leaks. This is a problem newly discovered by the present inventors.

[0012] Therefore, the present inventors considered the configuration of an air conditioner capable of removing dust from the air filter in order to improve safety in an air conditioner using a flammable refrigerant, and arrived at the following invention.

[0013] Hereinafter, embodiments of the present disclosure will be described while referring to the drawings in some cases. However, the following embodiments are examples for explaining the present disclosure, and are not intended to limit the present disclosure to the following contents (for example, the shape, dimensions, arrangement, etc. of each component). The positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings unless otherwise specified. Each drawing described in the following embodiments is a schematic drawing, and the ratio of the size and thickness of each component in each drawing does not necessarily reflect the actual dimensional ratio. Also, the dimensional ratios of each element are not limited to the ratios shown in the drawings.

[0014] In the following description, when it is necessary to distinguish between a plurality of components from each other, prefixes such as "first" and "second" are attached to the names of the components, but when they can be distinguished from each other by the reference numerals attached to the components, the prefixes such as "first" and "second" may be omitted in consideration of the readability of the text.

[0015] (Embodiment 1) [Overall Configuration] FIG. 1 is a schematic view of an air conditioner 10 according to Embodiment 1 of the present disclosure. FIG. 2 is an enlarged schematic view of the indoor unit 20 of the air conditioner 10 in FIG. 1. FIG. 3 is a block diagram showing the internal configuration of the air conditioner 10 in FIG. 1.

[0016] As shown in FIG. 1, the air conditioner 10 according to the present embodiment includes an indoor unit 20 disposed in the indoor area Rin to be air-conditioned and an outdoor unit 30 disposed in the outdoor area Rout.

[0017] As shown in FIGS. 1 and 3, the outdoor unit 30 is provided with an outdoor heat exchanger 32 that exchanges heat with outdoor air A2, and an outdoor fan 34 that draws outdoor air A2 into the outdoor unit 30 and blows the outdoor air A2 after heat exchange with the outdoor heat exchanger 32 to the outdoor area Rout. The outdoor unit 30 is also provided with a compressor 36, an expansion valve 38, and a four-way valve 40 that execute a refrigeration cycle with the indoor heat exchanger 23 and the outdoor heat exchanger 32.

[0018] As shown in FIGS. 2 and 3, the indoor unit 20 includes an indoor heat exchanger 23, an air filter 24, a cleaning device 25, and a control unit 26. The indoor heat exchanger 23, the air filter 24, and the control unit 26 are housed in the housing 21 of the indoor unit 20. The housing 21 of the indoor unit 20 is provided with an intake port 21a and an outlet port 21b for indoor air A1. An indoor fan 22 is disposed inside the housing 21 to form an air flow F1 from the intake port 21a to the outlet port 21b. The indoor fan 22 draws indoor air A1 into the indoor unit 20 from the intake port 21a and blows the indoor air A1 after heat exchange with the indoor heat exchanger 23 to the indoor area Rin from the outlet port 21b. The indoor heat exchanger 23 is disposed in the path of the air flow F1 formed by the indoor fan 22 and exchanges heat with the indoor air A1.

[0019] As shown in Figure 1, the indoor heat exchanger 23 of the indoor unit 20 and the outdoor heat exchanger 32, compressor 36, and expansion valve 38 of the outdoor unit 30 are connected by refrigerant piping 50. Refrigerant circulates through the refrigerant piping 50. In this embodiment, a flammable refrigerant such as propane (R290), isobutane (R600a), ethane (R170), propylene (R-1270), or ammonia (R-717) is used as the refrigerant.

[0020] The air filter 24 is a filter that allows indoor air A1, which is heading towards the indoor heat exchanger 23, to pass through and capture foreign matter such as dust contained in the indoor air A1. The air filter 24 is placed in the airflow path from indoor air Rin to indoor heat exchanger 23.

[0021] The air filter 24 is made of a flame-retardant material. As the flame-retardant material, for example, glass fiber, or a material combining glass fiber as the main component with non-combustible or flame-retardant inorganic fibers, can be used. Examples of non-combustible or flame-retardant inorganic fibers include ceramic fibers, metal fibers, carbon fibers, and aromatic polyamide fibers. By making the air filter 24 of a flame-retardant material, even if foreign matter adhering to the air filter 24 ignites from leaked refrigerant, the combustion of the air filter 24 can be suppressed.

[0022] The indoor air A1, which has passed through the air filter 24 and undergone heat exchange in the indoor heat exchanger 23, is blown out into the indoor Rin from the outlet 21b.

[0023] The cleaning device 25 is a device that removes foreign matter such as dust adhering to the air filter 24. The cleaning device 25 includes, for example, a brush. The cleaning device 25 cleans the air filter 24 by scraping off foreign matter such as dust adhering to the surface of the air filter 24 with the brush or the like. The foreign matter such as dust scraped off by the brush or the like is collected in, for example, a dust box (not shown) or discharged to the outdoor Rout.

[0024] The control unit 26 controls the indoor fan 22 and the cleaning device 25. In this embodiment, the control unit 26 controls the indoor fan 22 to draw indoor air A1 into the indoor unit 20 and to control a series of operations in which the indoor air A1, which has exchanged heat with the indoor heat exchanger 23, is discharged from the outlet 21b. In this embodiment, the control unit 26 can perform heating and cooling operations. In heating operation, the control unit 26 controls the indoor fan 22 to discharge indoor air A1, which has been heated by the indoor heat exchanger 23, from the outlet 21b to the indoor Rin. In cooling operation, the control unit 26 controls the indoor fan 22 to discharge indoor air A1, which has been cooled by the indoor heat exchanger 23, from the outlet 21b to the indoor Rin.

[0025] The control unit 26 includes, for example, a memory that stores a program and a processing circuit corresponding to a processor such as a CPU (Central Processing Unit). The functions of the control unit 26 may be configured solely with hardware, or they may be realized by a combination of hardware and software. The control unit 26 realizes predetermined functions by reading data and programs stored in memory and performing various arithmetic operations.

[0026] The user selects between heating and cooling operation. For example, the user selects operation via the terminal device 72 shown in Figure 1, and either heating or cooling operation is performed in response to that operation. The terminal device 72 is a terminal capable of transmitting signals to the control unit 26 indicating the start or end of operation of the air conditioner 10. Examples of the terminal device 72 include electronic devices such as a remote controller, smartphone, or tablet. In this embodiment, the case where the terminal device 72 is a remote controller will be described.

[0027] Furthermore, the control unit 26 controls the cleaning device 25 to perform filter cleaning to remove dust from the air filter 24. Figure 4 is a timing chart showing the control of filter cleaning. Figure 5 is a timing chart showing the control of filter cleaning when a signal to interrupt filter cleaning is received.

[0028] For example, when a user operates the remote controller 72 and presses a button to stop heating or cooling operation, the control unit 26 receives a signal to stop heating or cooling operation and stops the heating or cooling operation. At this time, the control unit 26 changes the filter cleaning execution status from standby to running and performs filter cleaning. Therefore, the control unit 26 starts performing filter cleaning when it stops heating or cooling operation. Alternatively, the control unit 26 may perform filter cleaning at a predetermined time. Alternatively, the control unit 26 may perform filter cleaning at a predetermined interval. For example, the control unit 26 may perform filter cleaning at a fixed time every day, or for example, every 24 hours. Alternatively, the control unit 26 may perform filter cleaning based on the fact that it has received a signal to start filter cleaning when the user operates the remote controller 72 and presses a button to start filter cleaning.

[0029] The filter cleaning execution status being "standby" indicates that filter cleaning is not currently being performed but is in a state where it can be performed. The control unit 26 starts filter cleaning and then, for example, ends it after a predetermined time has elapsed or after a predetermined area of ​​the air filter 24 has been cleaned. In the example in Figure 4, the control unit 26 starts executing filter cleaning at time t1 and ends it at time t2 because the predetermined time has elapsed. After the filter cleaning is completed at time t2, the filter cleaning execution status returns to "standby".

[0030] Filter cleaning is often performed when heating or cooling operation is stopped. For this reason, if filter cleaning is performed when heating or cooling operation is stopped, the operating noise of the filter cleaning may be considered noise and cause discomfort to the user. In this case, it is conceivable that the control unit 26 may receive a signal to interrupt filter cleaning when the user operates the remote controller 72, and interrupt the filter cleaning. In this embodiment, the control unit 26 resumes the execution of filter cleaning or makes the filter cleaning ready to be performed after a predetermined cleaning interruption time has elapsed since the filter cleaning was interrupted.

[0031] Referring to Figure 5, the control for resuming filter cleaning after a predetermined cleaning interruption period has elapsed will be described.

[0032] The control unit 26 receives a signal to start filter cleaning at time t11 and begins the filter cleaning process. At time t12, when the user operates the remote controller 72, the control unit 26 receives a signal to interrupt filter cleaning and interrupts the filter cleaning. After interrupting filter cleaning at time t12 and after a predetermined cleaning interruption time S1 has elapsed, the control unit 26 resumes the filter cleaning process at time t13. In the example in Figure 5, the predetermined cleaning interruption time S1 is between time t12 and time t13. After resuming the filter cleaning process at time t13, the control unit 26 terminates the filter cleaning at time t14 after a predetermined time has elapsed or after cleaning a predetermined range of the air filter 24 has been completed.

[0033] The control unit 26 receives a signal to interrupt filter cleaning and then interrupts the cleaning process. After a predetermined cleaning interruption time has elapsed, the control unit 26 restarts the filter cleaning, thereby ensuring that dust and other foreign matter adhering to the air filter 24 are reliably removed. As a result, even if a flammable refrigerant leaks inside the indoor unit 20 and ignites, the spread of fire can be suppressed.

[0034] [effect] According to the embodiment described above, the following effects can be achieved.

[0035] The air conditioner 10 is an air conditioner that uses a flammable refrigerant. The air conditioner 10 comprises an indoor heat exchanger 23, an air filter 24, a cleaning device 25, and a control unit 26. The indoor heat exchanger 23 exchanges heat with indoor air A1. Indoor air A1 passing from indoor Rin towards the indoor heat exchanger 23 passes through the air filter 24. The cleaning device 25 cleans the air filter 24. The control unit 26 controls the cleaning device 25. The control unit 26 drives the cleaning device 25 to perform filter cleaning, which removes dust adhering to the air filter 24.

[0036] This configuration makes it possible to provide an air conditioner that improves safety when using flammable refrigerants. Since dust and other foreign matter adhering to the air filter 24 is often highly flammable, cleaning the air filter 24 with the cleaning device 25 to remove dust can suppress the spread of fire by preventing refrigerant leakage from igniting the dust and other foreign matter.

[0037] The air filter 24 is made of flame-retardant material.

[0038] Dust and other foreign matter can adhere to the air filter 24. Therefore, by constructing the air filter 24 from a flame-retardant material, it is possible to suppress the combustion of the air filter 24 even if refrigerant leaks, thereby improving the safety of the air conditioner.

[0039] When the control unit 26 receives a signal to interrupt the execution of filter cleaning, it interrupts the execution of filter cleaning and resumes the execution of filter cleaning after a predetermined cleaning interruption period has elapsed.

[0040] This configuration ensures that even if the user interrupts the filter cleaning process, the filter cleaning can be reliably performed to remove dust adhering to the air filter 24.

[0041] [Differentiation] Figure 6 is a timing chart showing the execution status of filter cleaning in an air conditioner according to a modified example 1 of Embodiment 1.

[0042] As shown in Figure 6, the control unit 26 may change the state to one where filter cleaning can be performed after it has received a signal to interrupt filter cleaning and interrupted the execution of filter cleaning, and after a predetermined cleaning interruption time S2 has elapsed. The state where filter cleaning can be performed means that filter cleaning is not being performed but can be performed, and in Figure 6 it is displayed as "standby". For example, when the control unit 26 receives a signal to stop heating or cooling operation and stops the heating or cooling operation, it starts performing filter cleaning at time t21. At time t22, when the user operates the remote controller 72, the control unit 26 receives a signal to interrupt filter cleaning and interrupts the execution of filter cleaning. After the predetermined cleaning interruption time S2 has elapsed since the filter cleaning was interrupted at time t22, the control unit 26 changes the execution state of filter cleaning to "standby" at time t23. That is, the control unit 26 returns to a state where filter cleaning can be performed after the predetermined cleaning interruption time S2 has elapsed. In the example in Figure 6, the predetermined cleaning interruption time S2 is the period from time t22 to time t23. By returning the system to a state where filter cleaning can be performed after a predetermined cleaning interruption time S2 has elapsed, the control unit 26 can perform filter cleaning at the appropriate timing. This allows dust on the air filter 24 to be removed at the appropriate time, thereby suppressing the spread of fire in the event of refrigerant leakage and ignition.

[0043] (Embodiment 2) Embodiment 2 will be described with reference to Figures 7 and 8. In Embodiment 2, components that are the same as or equivalent to those in Embodiment 1 will be denoted by the same reference numerals. Also, in Embodiment 2, descriptions that are redundant with Embodiment 1 will be omitted.

[0044] Figure 7 is a schematic diagram showing the indoor unit 20A of the air conditioner according to Embodiment 2. Figure 8 is a schematic diagram showing an enlarged view of region R1 in Figure 7. As shown in Figures 7 to 8, Embodiment 2 differs from Embodiment 1 in that the air conditioner is equipped with a dust box 27 for collecting the removed dust. Also, as shown in Figure 8, the cleaning device 25 differs from Embodiment 1 in that it has a brush 25a and a roller 25b. The other components of the air conditioner are the same as in Embodiment 1, so their description is omitted.

[0045] As shown in Figures 7 and 8, a dust box 27 is provided in the indoor unit 20A. The dust box 27 is a component for collecting removed dust, and the dust removed by the cleaning device 25 cleaning the air filter 24 is placed in the dust box 27.

[0046] The dust box 27 is constructed from a material that is more flame-retardant than the materials used in other components of the air conditioner. Flame retardancy is an indicator of how difficult a material is to burn. A material that is more flame-retardant than the materials used in other components of the air conditioner is, for example, sheet metal. By constructing the dust box 27 from a material that is more flame-retardant than the materials used in other components of the air conditioner, it is possible to suppress the spread of fire from the dust collected inside the dust box 27.

[0047] The cleaning device 25 includes a brush 25a and a roller 25b. The brush 25a is made of, for example, a flame-retardant material. As the flame-retardant material, for example, glass fibers, or a material that combines glass fibers as the main component with non-combustible or flame-retardant inorganic fibers can be used. Examples of non-combustible or flame-retardant inorganic fibers include ceramic fibers, metal fibers, carbon fibers, aromatic polyamide fibers, etc. By making the brush 25a out of a flame-retardant material, even if dust remains attached to the brush 25a, the spread of fire can be suppressed.

[0048] Referring to Figure 8, the cleaning device 25 and dust box 27 in this embodiment will be described in more detail.

[0049] As shown in Figure 8, the cleaning device 25 has a brush 25a and a roller 25b. When the control unit 26 starts the execution of filter cleaning, the brush 25a is pressed against the surface of the air filter 24. At the same time that the brush 25a is pressed against the surface of the air filter 24, the roller 25b winds up the air filter 24 in the direction of arrow B1. By pressing the brush 25a against the air filter 24 and winding up the air filter 24 with the roller 25b, dust on the surface of the air filter 24 is scraped off and falls into the dust box 27. The scraped-off dust is collected in the dust box 27.

[0050] [effect] According to the embodiment described above, the following effects can be achieved.

[0051] The cleaning device 25 has a brush 25a for removing dust from the air filter 24. The brush 25a is made of a flame-retardant material.

[0052] This configuration helps to suppress the spread of fire even if dust remains attached to the brush 25a.

[0053] The air conditioner also includes a dust box 27 for collecting the removed dust.

[0054] The materials used to construct the dustbin are more flame-retardant than the materials used in other components of the air conditioner.

[0055] This configuration helps to prevent the dust collected inside the dustbin 27 from spreading fire.

[0056] Alternatively, instead of constructing the dust box 27 from a highly flame-retardant material, the thickness of the material constituting the dust box 27 may be made thicker than that of other components included in the air conditioner. In this case, the dust box 27 may be made from the same material as the air conditioner's casing. By making the thickness of the material constituting the dust box 27 thicker than that of other components included in the air conditioner, it is possible to suppress the spread of fire from the dust collected in the dust box 27.

[0057] [Differentiation] Figure 9 is a schematic diagram showing an indoor unit 20B of an air conditioner according to a modified example 1 of Embodiment 2. As shown in Figure 9, the air conditioner may also be equipped with a discharge unit 28 that discharges dust accumulated in the dust box 27 to the outdoor Rout.

[0058] The discharge unit 28 includes, for example, a duct 28a connecting the dust box 27 to the outdoor Rout, and a suction fan 28b. The suction fan 28b can suck up dust accumulated in the dust box 27 and discharge it to the outdoor Rout via the duct 28a. By discharging the dust to the outdoor Rout, which is outside the air conditioner, it is possible to suppress the spread of fire inside the indoor unit 20B caused by ignition of leaked refrigerant.

[0059] Figures 10 and 11 are schematic diagrams showing a dust box 27 according to a modified example 2 of Embodiment 2. The air conditioner may be equipped with a lid 29 that can be opened and closed on the dust box 27.

[0060] Figure 10 shows the dust box 27 closed by the lid 29, and Figure 11 shows the lid 29 open. When filter cleaning is not being performed, the dust box 27 is closed by the lid 29. On the other hand, when filter cleaning is being performed, the lid 29 is opened, allowing dust and other foreign matter scraped out by the brush to be placed into the dust box 27.

[0061] As shown in Figure 10, when the dust box 27 is closed by the lid 29, it is desirable that the gap D1 between the dust box 27 and the lid 29 is smaller than the flame extinguishing diameter of the refrigerant, or that the dust box 27 is sealed by the lid 29. The flame extinguishing diameter of the refrigerant is the size of the gap that causes a sustained flame to be extinguished. For example, if the refrigerant is propane (R290), the flame extinguishing diameter is 0.4 mm. Therefore, it is preferable that the size of the gap D1 is smaller than 0.4 mm. By having a gap between the dust box 27 and the lid 29 that is smaller than the flame extinguishing diameter, or by having no gap at all, it is possible to suppress the spread of fire to the dust accumulated in the dust box 27.

[0062] (Embodiment 3) Embodiment 3 will be described with reference to Figure 12. In Embodiment 3, components that are the same as or equivalent to those in Embodiment 1 will be denoted by the same reference numerals. Also, in Embodiment 3, descriptions that overlap with those in Embodiment 1 will be omitted.

[0063] Figure 12 is a timing chart showing the control of filter cleaning when a signal to interrupt filter cleaning is received in the air conditioner according to Embodiment 3. Embodiment 3 differs from Embodiment 1 in that, as shown in Figure 12, filter cleaning continues even when a signal to interrupt filter cleaning is received if the time since the end of filter cleaning exceeds a predetermined cumulative time. The configuration of the air conditioner is the same as in Embodiment 1, so a description is omitted.

[0064] In the example shown in Figure 12, the control unit 26 starts the filter cleaning process at time t31, for example, when the heating or cooling operation stops. Subsequently, for example, after a predetermined time has elapsed, the control unit 26 terminates the filter cleaning process at time t32.

[0065] After the filter cleaning is completed, the control unit 26 starts the filter cleaning process again at time t33. Then, at time t34, the control unit 26 receives a signal to interrupt the filter cleaning process when the user operates the remote controller 72 and presses the button to interrupt the filter cleaning process, and interrupts the filter cleaning process. In this case, the filter cleaning that started at time t33 is interrupted midway. Subsequently, the control unit 26 starts the filter cleaning process multiple times, but receives a signal to interrupt the filter cleaning process, and if the filter cleaning remains interrupted, the interrupted state of the filter cleaning will exceed a predetermined cumulative time. In other words, each time the control unit 26 starts the filter cleaning process, the user operates the remote controller 72 and presses the button to interrupt the filter cleaning process, causing the control unit 26 to interrupt the filter cleaning process. In this case, the filter cleaning remains interrupted and unfinished, and the interrupted state of the filter cleaning will continue beyond a predetermined cumulative time. The predetermined cumulative time is the amount of time during which the interrupted state of filter cleaning can continue. When the control unit 26 receives a signal to interrupt filter cleaning, if the time elapsed since the end of filter cleaning exceeds a predetermined cumulative time, it ignores the signal to interrupt filter cleaning and continues filter cleaning. By setting a predetermined cumulative time, it is possible to prevent the state in which air filter cleaning is interrupted from continuing beyond that predetermined cumulative time. Therefore, by setting a predetermined cumulative time, the air filter 24 can be cleaned periodically, and the spread of dust into the fire can be suppressed.

[0066] In the example shown in Figure 12, the control unit 26 receives a signal to start filter cleaning at time t37 and begins cleaning the filter, and receives a signal to interrupt filter cleaning at time t38. However, the control unit 26 continues cleaning the filter without interrupting it at time t38. Subsequently, the control unit 26 finishes cleaning the filter at time t39. When the control unit 26 receives a signal to interrupt filter cleaning at time t38, it determines that the time elapsed since the end of the filter cleaning process has exceeded a predetermined cumulative time. That is, the control unit 26 determines that the time elapsed from time t32 to time t38 has exceeded a predetermined cumulative time. Therefore, the control unit 26 continues cleaning the filter without interrupting it at time t38.

[0067] If the time elapsed since the end of filter cleaning exceeds a predetermined cumulative time, it means that filter cleaning has been interrupted repeatedly during that predetermined cumulative time, and has never been completed to completion. If the time elapsed since the end of filter cleaning exceeds the predetermined cumulative time, the filter cleaning can be completed at least once within the predetermined cumulative time by ignoring the signal to interrupt filter cleaning.

[0068] The predetermined cumulative time can be set to, for example, 168 hours. In this case, filter cleaning can be performed completely at least once every 168 hours. The predetermined cumulative time can be set to any value, not limited to 168 hours.

[0069] The control unit 26 may, for example, notify the display unit of the remote controller 72 of a warning when it continues filter cleaning even after receiving a signal to interrupt filter cleaning at time t38. In addition to the display unit of the remote controller 72, the notification may also be sent to an app on an electronic device such as a smartphone or tablet. The warning may contain content such as, for example, "Filter cleaning has been interrupted multiple times in a row."

[0070] This configuration ensures that the air filter 24 is cleaned reliably even when a signal to interrupt filter cleaning is received, thereby improving the safety of the air conditioner.

[0071] Furthermore, when the dust box 27 is closed by the lid 29, the dust box 27 may be sealed by the lid 29. In this case, even if the refrigerant ignites, it is possible to suppress the spread of fire to the dust in the dust box 27.

[0072] (Note) Based on the above description of embodiments, the following technologies are disclosed.

[0073] (Technology 1) An air conditioner using a flammable refrigerant, comprising: an indoor heat exchanger that exchanges heat with indoor air; an air filter through which indoor air from the room to the indoor heat exchanger passes; a cleaning device for cleaning the air filter; and a control unit that controls the cleaning device, wherein the control unit drives the cleaning device to perform filter cleaning to remove dust adhering to the air filter.

[0074] This configuration makes it possible to provide an air conditioner that offers improved safety when using flammable refrigerants.

[0075] (Technology 2) The air filter is made of flame-retardant material, as described in Technology 1 of the air conditioner.

[0076] This configuration helps to suppress the spread of fire in the event of ignition of leaked refrigerant.

[0077] (Technology 3) The air conditioner according to Technology 1 or 2, wherein the control unit, upon receiving a signal to interrupt the execution of filter cleaning, interrupts the execution of filter cleaning and resumes the execution of filter cleaning or makes the unit ready to perform filter cleaning after a predetermined cleaning interruption period has elapsed.

[0078] This configuration ensures that the air filter can be cleaned thoroughly.

[0079] (Technology 4) The control unit continues filter cleaning even if it receives a signal to interrupt filter cleaning if the time elapsed since the completion of filter cleaning exceeds a predetermined cumulative time, according to any one of the technologies 1 to 3.

[0080] This configuration ensures that the air filter is reliably cleaned at predetermined cumulative intervals.

[0081] (Technology 5) Furthermore, the air conditioner according to Technology 4, further comprising a notification unit for notifying the user of information, wherein the control unit, when it receives a signal to interrupt the execution of filter cleaning, continues to provide a warning via the notification unit.

[0082] This configuration allows the user to be notified of the long interruption in filter cleaning.

[0083] (Technology 6) The cleaning device has a brush for removing dust from the air filter, and the brush is made of a flame-retardant material, according to any one of the technologies 1 to 5 of the air conditioner.

[0084] This configuration helps to prevent the cleaning equipment from being caught in a fire.

[0085] (Technology 7) Furthermore, the air conditioner according to any one of technologies 1 to 6 is further equipped with a dust box for collecting the removed dust.

[0086] This configuration allows the removed dust to be contained in a dust box, thereby suppressing the spread of fire to the collected dust.

[0087] (Technology 8) Furthermore, the air conditioner according to Technology 7 is further equipped with a lid that can be opened and closed, wherein when the dust box is closed by the lid, the gap between the dust box and the lid is smaller than the flame extinguishing diameter of the refrigerant.

[0088] This configuration helps to prevent the spread of fire to the dust collected in the dustbin.

[0089] (Technology 9) The air conditioner described in Technology 7 or 8, wherein the thickness of the material constituting the dustbin is greater than the thickness of the material of other components included in the air conditioner.

[0090] This configuration makes the dustbin less likely to burn, thus suppressing the spread of fire to dust.

[0091] (Technology 10) The air conditioner described in Technology 7 or 8, wherein the materials constituting the dustbin are more flame-retardant than the materials of other components included in the air conditioner.

[0092] This configuration makes the dustbin less likely to burn, thus suppressing the spread of fire to dust.

[0093] (Technology 11) Furthermore, the air conditioner according to any one of technologies 7 to 10 is further equipped with a discharge unit for discharging dust accumulated in a dust box to the outside.

[0094] This configuration allows dust to be discharged to the outside of the air conditioner, thereby reducing the risk of fire spreading. [Industrial applicability]

[0095] This disclosure is applicable to air conditioners that use flammable refrigerants. [Explanation of symbols]

[0096] 10. Air conditioner 20, 20A, 20B indoor unit 21 cabinets 23 Indoor heat exchanger 24 Air Filter 25 Cleaning equipment 25a Brush 25b Laura 26 Control Unit 27 Dustbin 28 Discharge section 29 Lid 72 Terminal devices

Claims

1. An air conditioner that uses a flammable refrigerant, An indoor heat exchanger that exchanges heat with indoor air, An air filter through which the indoor air passing from the room toward the indoor heat exchanger, A cleaning device for cleaning air filters, A control unit that controls the cleaning device, Equipped with, The control unit drives the cleaning device to perform filter cleaning, which removes dust adhering to the air filter. Air conditioner.

2. The aforementioned air filter is made of a flame-retardant material. The air conditioner according to claim 1.

3. When the control unit receives a signal to interrupt the execution of the filter cleaning, it interrupts the execution of the filter cleaning and, after a predetermined cleaning interruption time has elapsed, resumes the execution of the filter cleaning or makes the filter cleaning ready to be performed. The air conditioner according to claim 1.

4. The control unit, if the time elapsed since the completion of the filter cleaning exceeds a predetermined cumulative time, will continue the filter cleaning even if it receives a signal to interrupt the filter cleaning. The air conditioner according to claim 1.

5. Furthermore, it includes a notification unit that notifies the user of information, The control unit, when it receives a signal to interrupt the filter cleaning process but continues the filter cleaning, notifies a warning via the notification unit. The air conditioner according to claim 4.

6. The cleaning device has a brush for removing dust from the air filter, The aforementioned brush is made of a flame-retardant material. The air conditioner according to claim 1.

7. moreover, A dustbin for collecting the removed dust. Equipped with, The air conditioner according to claim 6.

8. moreover, A lid is provided on the dustbin that can be opened and closed. Equipped with, When the dust box is closed by the lid, the gap between the dust box and the lid is smaller than the flame extinguishing diameter of the refrigerant. The air conditioner according to claim 7.

9. The thickness of the material constituting the dust box is greater than the thickness of the material of other components included in the air conditioner. The air conditioner according to claim 7.

10. The material constituting the dust box has higher flame retardancy than the material of other components included in the air conditioner. The air conditioner according to claim 7.

11. moreover, A discharge unit for discharging dust accumulated in the aforementioned dust box to the outside. Equipped with, The air conditioner according to claim 7.

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