Air conditioner

Abstract

An air conditioner according to the present disclosure uses a flammable refrigerant and includes an indoor heat exchanger that exchanges heat with indoor air, an air filter through which the indoor air flowing from an indoor space to the indoor heat exchanger passes, a cleaner that cleans the air filter, and a controller that controls the cleaner, wherein the controller drives the cleaner to perform filter cleaning for removing dust adhering to the air filter.

Description

TECHNICAL FIELD

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

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

[0003] For example, an air conditioner described in Patent Document 1 includes a filter that collects dust of sucked air, a cleaning mechanism that removes the dust collected by the filter, and a controller that controls driving of the cleaning mechanism.PRIOR ART DOCUMENTPATENT DOCUMENT

[0004] Patent Document 1: JP 7037575 BSUMMARY OF THE IVENTIONPROBLEMS TO BE SOLVED BY THE INVENTION

[0005] In the air conditioner described in Patent Document 1, there is still room for improvement regarding safety in a case where a flammable refrigerant is used.

[0006] The present disclosure provides an air conditioner with improved safety for a case where a flammable refrigerant is used.SOLUTIONS TO THE PROBLEMS

[0007] An air conditioner according to one aspect of the present disclosure is an air conditioner using a flammable refrigerant, comprising: an indoor heat exchanger that exchanges heat with indoor air; an air filter through which the indoor air flowing from an indoor space to the indoor heat exchanger passes; a cleaner that cleans an air filter; and a controller that controls the cleaner; wherein the controller drives the cleaner to perform filter cleaning for removing dust adhering to the air filter.EFFECTS OF THE INVENTION

[0008] According to the present disclosure, it is possible to provide an air conditioner with improved safety for a case where a flammable refrigerant is used.BRIEF DESCRIPTION OF DRAWINGS

[0009] Fig. 1 is a schematic view of an air conditioner according to a first embodiment of the present disclosure; Fig. 2 is an enlarged schematic view of the indoor unit of the air conditioner in Fig. 1; Fig. 3 is a block diagram illustrating an internal configuration of the air conditioner in Fig. 1; Fig. 4 is a timing chart illustrating control of filter cleaning; Fig. 5 is a timing chart illustrating control of filter cleaning in a case where a signal for interrupting filter cleaning is received; Fig. 6 is a timing chart illustrating an execution state of filter cleaning in the air conditioner according to a first modification of the first embodiment; Fig. 7 is a schematic view illustrating an indoor unit of an air conditioner according to a second embodiment; Fig. 8 is an enlarged schematic view of a region R1 in Fig. 7; Fig. 9 is a schematic view illustrating an indoor unit of an air conditioner according to a first modification of the second embodiment; Fig. 10 is a schematic view illustrating a dust box according to a second modification of the second embodiment; Fig. 11 is a schematic view illustrating a dust box according to a second modification of the second embodiment; and Fig. 12 is a timing chart illustrating control of filter cleaning in a case where a signal for interrupting filter cleaning is received in the air conditioner according to a third embodiment. DETAILED DESCRIPTION(Background to the Present Disclosure)

[0010] In recent years, from the viewpoint of prevention of global warming, it is required to use a refrigerant having a low global warming potential (GWP). As a refrigerant having a low GWP, for example, propane (R290) or the like has been considered. Since a refrigerant such as propane has flammability, for example, when the refrigerant leaks in an indoor unit of an air conditioner, the refrigerant may be ignited, and it is important to improve safety.

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

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

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings as the case may be. However, the following embodiments are merely examples for describing the present disclosure, and are not intended to limit the present disclosure to the following contents (for example, the shape, dimensions, arrangement, and the like of each constituent element). The positional relationship such as up, down, left, and right is based on the positional relationship illustrated in the drawings unless otherwise specified. Each drawing described in the following embodiment is a schematic view, and the ratios of the sizes and the thicknesses of the respective components in each drawing do not necessarily reflect the actual dimensional ratios. The dimensional ratio of each element is not limited to the ratio illustrated in the drawings.

[0014] Note that, in the following description, in a case where it is necessary to distinguish a plurality of constituent elements from each other, prefixes such as "first" and "second" are added to the names of the constituent elements. However, in a case where the constituent elements can be distinguished from each other by reference numerals attached to the constituent elements, prefixes such as "first" and "second" may be omitted in consideration of sentence readability.(First Embodiment)[Overall Configuration]

[0015] Fig. 1 is a schematic view of an air conditioner 10 according to a first embodiment of the present disclosure. Fig. 2 is an enlarged schematic view of an indoor unit 20 of the air conditioner 10 in Fig. 1. Fig. 3 is a block diagram illustrating an internal configuration of the air conditioner 10 in Fig. 1.

[0016] As illustrated in Fig. 1, the air conditioner 10 according to the present embodiment includes the indoor unit 20 installed in an indoor space Rin to be air-conditioned and an outdoor unit 30 installed in an outdoor space Rout.

[0017] As illustrated in Figs. 1 and 3, the outdoor unit 30 is provided with an outdoor heat exchanger 32 that performs heat exchange with outdoor air A2, and an outdoor fan 34 that induces the 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 space Rout. The outdoor unit 30 is provided with a compressor 36 that performs a refrigeration cycle including an indoor heat exchanger 23 and an outdoor heat exchanger 32, an expansion valve 38, and a four-way valve 40.

[0018] As illustrated in Figs. 2 and 3, the indoor unit 20 includes the indoor heat exchanger 23, an air filter 24, a cleaner 25, and a controller 26. The indoor heat exchanger 23, the air filter 24, and the controller 26 are accommodated in a casing 21 of the indoor unit 20. The casing 21 of the indoor unit 20 is provided with an air suction port 21a and an air outlet 21b for indoor air A1. An indoor fan 22 is disposed inside the casing 21, and forms an airflow F1 from the air suction port 21a to the air outlet 21b. The indoor fan 22 induces the indoor air A1 from the air suction port 21a into the indoor unit 20, and blows the indoor air A1 after heat exchange with the indoor heat exchanger 23 from the air outlet 21b into the indoor space Rin. The indoor heat exchanger 23 is disposed in a path of the airflow F1 formed by the indoor fan 22 and exchanges heat with the indoor air A1.

[0019] As illustrated in Fig. 1, the indoor heat exchanger 23 of the indoor unit 20 is connected to the outdoor heat exchanger 32, the compressor 36, and the expansion valve 38 of the outdoor unit 30 by a refrigerant pipe 50. A refrigerant circulates through the refrigerant pipe 50. In the present embodiment, for example, a flammable refrigerant such as propane (R290), isobutane (R600a), ethane (R170), propylene (R-1270), ammonia (R-717), or the like is used as the refrigerant.

[0020] The air filter 24 is a filter that allows the indoor air A1 traveling toward the indoor heat exchanger 23 to pass therethrough and captures foreign matter such as dust contained in the indoor air A1. The air filter 24 is disposed in an airflow path from the indoor space Rin to the 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 obtained by combining non-flammable or flame-retardant inorganic fibers with glass fiber as a main component can be adopted. Examples of the non-flammable or flame-retardant inorganic fibers include fibers such as ceramic fibers, metal fibers, carbon fibers, and aromatic polyamide fibers. Using the air filter 24 made of the flame-retardant material, combustion of the air filter 24 can be suppressed even if foreign matter adhering to the air filter 24 is ignited by the leaking refrigerant.

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

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

[0024] The controller 26 controls the indoor fan 22 and the cleaner 25. In the present embodiment, the controller 26 controls the indoor fan 22 to perform a series of operations of inducing the indoor air A1 to the indoor unit 20 and discharging the indoor air A1 heat-exchanged with the indoor heat exchanger 23 from the air outlet 21b. In the present embodiment, the controller 26 can execute a heating operation and a cooling operation. During the heating operation, the controller 26 controls the indoor fan 22 to discharge the indoor air A1 warmed by the indoor heat exchanger 23 from the air outlet 21b to the indoor space Rin. In the cooling operation, the controller 26 controls the indoor fan 22 to discharge the indoor air A1 cooled by the indoor heat exchanger 23 from the air outlet 21b to the indoor space Rin.

[0025] The controller 26 includes, for example, a memory that stores a program and a processing circuit corresponding to a processor such as a central processing unit (CPU). The function of the controller 26 may be configured only by hardware, or may be realized by combining hardware and software. The controller 26 reads data and programs stored in the memory and performs various arithmetic processing to realize a predetermined function.

[0026] The heating operation or the cooling operation is selected by a user. For example, the heating operation or the cooling operation is executed according to the user's selection operation by a terminal device 72 illustrated in Fig. 1. The terminal device 72 is a terminal that can transmit a signal indicating the start, end or the like of the operation of the air conditioner 10 to the controller 26. Examples of the terminal device 72 include electronic devices such as a remote controller, a smartphone, and a tablet. In the present embodiment, a case where the terminal device 72 is a remote controller will be described.

[0027] The controller 26 also controls the cleaner 25 to perform filter cleaning for removing dust from the air filter 24. Fig. 4 is a timing chart illustrating control of filter cleaning. Fig. 5 is a timing chart illustrating control of filter cleaning in a case where a signal for interrupting filter cleaning is received.

[0028] For example, in a case where a user operates a remote controller 72 to press a button for stopping the heating operation or the cooling operation, the controller 26 receives a signal for stopping the heating operation or the cooling operation and stops the heating operation or the cooling operation. At this time, the controller 26 changes an execution state of filter cleaning from a standby state to an active state, and executes filter cleaning. Therefore, in a case where the heating operation or the cooling operation is stopped, the controller 26 starts the execution of the filter cleaning. Alternatively, the controller 26 may perform the filter cleaning at a predetermined time. Alternatively, the controller 26 may perform the filter cleaning at predetermined intervals. For example, the controller 26 can execute the filter cleaning at a fixed time every day, or can execute the filter cleaning every 24 hours, for example. Alternatively, in a case where the user operates the remote controller 72 to press a button for starting the filter cleaning, the controller 26 can execute the filter cleaning based on reception of a signal for starting the filter cleaning by the controller 26.

[0029] The execution state of the filter cleaning being the standby state indicates that the filter cleaning is not being executed but is executable. The controller 26 ends the filter cleaning after, for example, a predetermined time elapses, or a predetermined area of the air filter 24 has been cleaned after the filter cleaning is started. In the example in Fig. 4, the controller 26 starts execution of the filter cleaning at time t1, and ends the filter cleaning since a predetermined time has elapsed at time t2. After the filter cleaning ends at time t2, the execution state of the filter cleaning returns to the standby state.

[0030] The filter cleaning is often performed while the heating operation or the cooling operation is stopped. For this reason, for example, in a case where the filter cleaning is executed while the heating operation or the cooling operation is stopped, the driving sound of the filter cleaning may be noise to the user and the user may feel discomfort. In this case, when the user operates the remote controller 72, the controller 26 may receive a signal to interrupt the filter cleaning and interrupt the filter cleaning. In the present embodiment, after a predetermined cleaning interruption time has elapsed since the interruption of the filter cleaning, the controller 26 resumes the execution of the filter cleaning or controls the filter cleaning to be executable.

[0031] With reference to Fig. 5, control for resuming the filter cleaning after a predetermined cleaning interruption time has elapsed from the interruption of the filter cleaning will be described.

[0032] The controller 26 receives a signal for starting the filter cleaning at time t11 and starts execution of the filter cleaning. When the user operates the remote controller 72 at time t12, the controller 26 receives an interruption signal of the filter cleaning and interrupts the filter cleaning. After a predetermined cleaning interruption time S1 elapses after the filter cleaning is interrupted at time t12, the controller 26 resumes the execution of the filter cleaning at time t13. The predetermined cleaning interruption time S1 corresponds to the period from the time t12 to the time t13 in the example in Fig. 5. In case where a predetermined time elapses after resuming the execution of the filter cleaning at the time t13 or the cleaning of the predetermined range of the air filter 24 is finished, the controller 26 ends the filter cleaning at time t14.

[0033] Since the controller 26 starts the filter cleaning after a predetermined cleaning interruption time elapses after the controller 26 receives a signal for interrupting the filter cleaning and interrupts the filter cleaning, foreign matter such as dust adhering to the air filter 24 can be reliably removed. Therefore, even if the flammable refrigerant leaks inside the indoor unit 20 and ignites, spread of fire can be suppressed.[Advantageous Effects]

[0034] According to the above-described embodiment, the following advantageous effects can be obtained.

[0035] The air conditioner 10 is an air conditioner using a flammable refrigerant. The air conditioner 10 includes the indoor heat exchanger 23, the air filter 24, the cleaner 25, and the controller 26. The indoor heat exchanger 23 exchanges heat with the indoor air A1. The indoor air A1 that flows from the indoor space Rin toward the indoor heat exchanger 23 passes through the air filter 24. The cleaner 25 cleans the air filter 24. The controller 26 controls the cleaner 25. The controller 26 drives the cleaner 25 to perform the filter cleaning for removing dust adhering to the air filter 24.

[0036] With such a configuration, it is possible to provide an air conditioner with improved safety for a case where a flammable refrigerant is used. Foreign matter such as dust adhering to the air filter 24 is likely to burn. Therefore, the air filter 24 is cleaned by the cleaner 25 to remove dust, so that even if the refrigerant leaks, it is possible to prevent dust or the like from being ignited and spreading fire.

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

[0038] Foreign matter such as dust adheres to the air filter 24. Accordingly, the air filter 24 made of a flame-retardant material prevents combustion of the air filter 24 even if a refrigerant leaks, thereby improving safety of the air conditioner.

[0039] When receiving a signal for interrupting the execution of the filter cleaning, the controller 26 interrupts the execution of the filter cleaning and resumes the execution of the filter cleaning after a predetermined cleaning interruption time elapses.

[0040] With such a configuration, even in a case where the filter cleaning is interrupted by a user, the filter cleaning can be reliably executed to remove dust adhering to the air filter 24.[Modification(s)]

[0041] Fig. 6 is a timing chart illustrating an execution state of filter cleaning in the air conditioner according to a first modification of the first embodiment.

[0042] As illustrated in Fig. 6, after a predetermined cleaning interruption time S2 elapses after the controller 26 receives a signal to interrupt the filter cleaning and interrupts the execution of the filter cleaning, the controller 26 may change to a state where the filter cleaning is executable. The state in which the filter cleaning is executable indicates a state in which the filter cleaning is not being performed but can be executed. In Fig. 6, it is displayed as "standby". The controller 26 starts execution of the filter cleaning at time t21 in a case where, for example, a stop signal of the heating operation or the cooling operation is received, and the heating operation or the cooling operation is stopped. In a case where the user operates the remote controller 72 at time t22, the controller 26 receives an interruption signal of the filter cleaning and interrupts the execution of the filter cleaning. After the predetermined cleaning interruption time S2 elapses after the filter cleaning is interrupted at the time t22, the controller 26 changes the execution state of the filter cleaning to the standby state at time t23. That is, the controller 26 returns the filter cleaning to an executable state after the predetermined cleaning interruption time S2 elapses. In the example in Fig. 6, the predetermined cleaning interruption time S2 indicates a period from the time t22 to the time t23. By returning to a state where the filter cleaning is executable after the lapse of the predetermined cleaning interruption time S2, the controller 26 can execute the filter cleaning at an appropriate timing. Therefore, dust on the air filter 24 can be removed at an appropriate timing to suppress spread of fire when the refrigerant leaks and ignites.(Second Embodiment)

[0043] A second embodiment will be described with reference to Figs. 7 to 8. In the second embodiment, the same or equivalent components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment. In the second embodiment, the description overlapping with the first embodiment is omitted.

[0044] Fig. 7 is a schematic view illustrating an indoor unit 20A of the air conditioner according to the second embodiment. Fig. 8 is an enlarged schematic view of a region R1 in Fig. 7. As illustrated in Figs. 7 to 8, the second embodiment is different from the first embodiment in that an air conditioner includes a dust box 27 that collects removed dust. As illustrated in Fig. 8, except that the cleaner 25 includes a brush 25a and a roller 25b, the configuration of the air conditioner is the same as that of the first embodiment, and the description thereof is omitted.

[0045] As illustrated in Figs. 7 and 8, the dust box 27 is disposed in the indoor unit 20A. The dust box 27 is a member for collecting removed dust, and dust removed by the cleaner 25 cleaning the air filter 24 is put into the dust box 27.

[0046] The dust box 27 is made of a material having higher flame retardancy than materials of other components included in the air conditioner. Flame retardancy is an indicator of a material's resistance to burning. The material having higher flame retardancy than the material of other components included in the air conditioner is, for example, an iron plate. By being made of a material having higher flame retardancy than other components included in the air conditioner, it is possible to suppress the spread of fire of dust collected inside the dust box 27.

[0047] The cleaner 25 includes the brush 25a and the roller 25b. The brush 25a is made of, for example, a flame-retardant material. As the flame-retardant material, for example, glass fiber or a material obtained by combining non-flammable or flame-retardant inorganic fibers with glass fiber as a main component can be adopted. Examples of the non-flammable or flame-retardant inorganic fibers include fibers such as ceramic fibers, metal fibers, carbon fibers, and aromatic polyamide fibers. The brush 25a is made of a flame-retardant material, so that spread of fire can be suppressed even when dust remains on the brush 25a.

[0048] The cleaner 25 and the dust box 27 according to the present embodiment will be described more specifically with reference to Fig. 8.

[0049] As illustrated in Fig. 8, the cleaner 25 includes the brush 25a and the roller 25b. In a case where controller 26 starts execution of the filter cleaning, the brush 25a is pressed against the surface of the air filter 24. At the same time as the brush 25a is pressed against the surface of the air filter 24, the air filter 24 is wound in the direction of an arrow B1 by the roller 25b. By winding the air filter 24 with the roller 25b while pressing the brush 25a against the air filter 24, dust on the surface of the air filter 24 is scraped off and falls into the dust box 27. The scraped dust is collected in the dust box 27.[Advantageous Effects]

[0050] According to the above-described embodiment, the following advantageous effects can be obtained.

[0051] The cleaner 25 includes the brush 25a that removes dust from the air filter 24. The brush 25a is made of a flame-retardant material.

[0052] With such a configuration, the spread of fire can be suppressed even when dust remains on the brush 25a.

[0053] The air conditioner further comprises the dust box 27 for collecting the removed dust.

[0054] The material forming the dust box has higher flame retardancy than that of other components included in the air conditioner.

[0055] With such a configuration, it is possible to suppress the spread of fire of dust collected inside the dust box 27.

[0056] Note that, instead of forming the dust box 27 from a material having high flame retardancy, for example, the material forming the dust box 27 may be formed to be thicker than the materials of other components included in the air conditioner. In this case, the dust box 27 may be made of the same material as the casing of the air conditioner. By making the material forming the dust box 27 thicker than the material of other parts included in the air conditioner, it is possible to suppress the spread of fire of dust collected inside the dust box 27.[Modification(s)]

[0057] Fig. 9 is a schematic view illustrating an indoor unit 20B of the air conditioner according to a first modification of the second embodiment. As illustrated in Fig. 9, the air conditioner may include a discharger 28 that discharges dust accumulated in the dust box 27 to the outdoor space Rout.

[0058] The discharger 28 includes, for example, a duct 28a that communicates the dust box 27 with the outdoor space Rout, and a suction fan 28b. The suction fan 28b can draw in dust accumulated in the dust box 27 and discharge the dust to the outdoor space Rout via the duct 28a. Dust is discharged to the outdoor space Rout outside the air conditioner, so that spread of fire inside the indoor unit 20B due to ignition of the leaking refrigerant can be suppressed.

[0059] Figs. 10 and 11 are schematic views illustrating the dust box 27 according to a second modification of the second embodiment. The air conditioner may include a lid 29 disposed in the dust box 27 so as to be openable and closable.

[0060] Fig. 10 illustrates a state in which the dust box 27 is closed by the lid 29, and Fig. 11 illustrates a state in which the lid 29 is opened. While the filter cleaning is not performed, the dust box 27 is closed by the lid 29. On the other hand, during the filter cleaning, the lid 29 is opened, and foreign matter such as dust scraped out by the brush can be put into the dust box 27.

[0061] As illustrated in Fig. 10, in a case where the dust box 27 is closed by the lid 29, it is desirable that a gap D1 between the dust box 27 and the lid 29 is a gap smaller than the extinction diameter of the refrigerant, or the dust box 27 is sealed by the lid 29. The extinction diameter of the refrigerant is the size of a gap that causes a continuously propagating flame to be extinguished. For example, in a case where the refrigerant is propane (R290), the extinction diameter is 0.4 mm. Therefore, the size of the gap D1 is preferably smaller than 0.4 mm. Since the gap between the dust box 27 and the lid 29 is smaller than the extinction diameter or no gap is provided, it is possible to suppress the spread of fire to dust accumulated in the dust box 27.(Third Embodiment)

[0062] A third embodiment will be described with reference to Fig. 12. In the third embodiment, the same or equivalent components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment. In the third embodiment, the description overlapping with the first embodiment is omitted.

[0063] Fig. 12 is a timing chart illustrating control of filter cleaning in a case where a signal for interrupting filter cleaning is received in the air conditioner according to the third embodiment. As illustrated in Fig. 12, the third embodiment is different from the first embodiment in that filter cleaning is continued even when a signal for interrupting filter cleaning is received, in a case where a time elapsed since completion of the filter cleaning exceeds a predetermined accumulation time. Since the configuration of the air conditioner is similar to that of the first embodiment, the description thereof will be omitted.

[0064] In the example in Fig. 12, the controller 26 starts the execution of the filter cleaning at time t31, for example, along with the stop of the heating operation or the cooling operation. Thereafter, for example, when a predetermined time has elapsed, the controller 26 ends the execution of the filter cleaning at time t32.

[0065] After completion of the filter cleaning, the controller 26 starts execution of the filter cleaning again at time t33. Thereafter, at time t34, the controller 26 receives a signal for interrupting filter cleaning by the user operating the remote controller 72 to press a button for interrupting the filter cleaning, and interrupts the filter cleaning. In this case, the filter cleaning started at the time t33 is interrupted halfway. Thereafter, in a case where the controller 26 starts the execution of the filter cleaning a plurality of times but interrupts the filter cleaning due to receiving the signal to interrupt the filter cleaning, the filter cleaning remains in an interrupted state, and the interrupted state of the filter cleaning continues for a period exceeding a predetermined accumulation time. In other words, every time the controller 26 starts execution of the filter cleaning, the user operates the remote controller 72 to press a button for interrupting execution of the filter cleaning, and the controller 26 interrupts execution of the filter cleaning. In this case, a state in which the filter cleaning is interrupted and not ended continues, and a state in which the filter cleaning is interrupted continues for a period exceeding a predetermined accumulation time. The predetermined accumulation time is a time during which the state in which the filter cleaning is interrupted can be continued. In a case where the time from the end of the filter cleaning exceeds the predetermined accumulation time when the signal to interrupt the filter cleaning is received, the controller 26 ignores the signal to interrupt the filter cleaning and continues the filter cleaning. By setting the predetermined accumulation time, it is possible to prevent the state in which the cleaning of the air filter is interrupted from being continued beyond the predetermined accumulation time. Therefore, by providing the predetermined accumulation time, the air filter 24 can be periodically cleaned, and the spread of fire to dust can be suppressed.

[0066] In the example in Fig. 12, the controller 26 receives a signal for starting the filter cleaning at time t37 to start the filter cleaning, and receives a signal for interrupting the filter cleaning at time t38. However, the controller 26 continues the filter cleaning without interrupting the filter cleaning at time t38. Thereafter, the controller 26 ends the filter cleaning at time t39. When the signal for interrupting the filter cleaning is received at time t38, the controller 26 determines that the time from the end of the execution of the filter cleaning has exceeded the predetermined accumulation time. That is, the controller 26 determines that the time from the time t32 to the time t38 exceeds the predetermined accumulation time. Therefore, at the time t38, the controller 26 continues the filter cleaning without interrupting the filter cleaning.

[0067] The fact that the time from the end of the filter cleaning exceeds the predetermined accumulation time means that the filter cleaning continues to be interrupted even if the filter cleaning is started for the predetermined accumulation time, and the filter cleaning has never been completed. In a case where the time from the end of the filter cleaning exceeds the predetermined accumulation time, it is ensured that the filter cleaning is completed at least once within the predetermined accumulation time by ignoring the signal for interrupting the filter cleaning.

[0068] The predetermined accumulation time can be, for example, 168 hours. In this case, it is ensured that the filter cleaning is completed to the end at least once every 168 hours. The predetermined accumulation time is not limited to 168 hours and can be set to any value.

[0069] For example, the controller 26 may notify a warning on a display of the remote controller 72 in a case where the filter cleaning is continued even when a signal for interrupting the filter cleaning is received at the time t38. In addition to the display of the remote controller 72, for example, a notification can be output to an application of an electronic device such as a smartphone or a tablet. The warning may be, for example, contents such as "filter cleaning has been interrupted multiple times consecutively".

[0070] With such a configuration, even when a signal for interrupting filter cleaning is received, the air filter 24 can be reliably cleaned, and the safety of the air conditioner can be improved.

[0071] It should be noted that 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 when the refrigerant is ignited, it is possible to suppress the spread of fire to dust in the dust box 27.(Supplemental Note)

[0072] The following technique is disclosed by the above description of the embodiments.(Technique 1)

[0073] An air conditioner using a flammable refrigerant, comprising: an indoor heat exchanger that exchanges heat with indoor air; an air filter through which the indoor air flowing from an indoor space to the indoor heat exchanger passes; a cleaner that cleans an air filter; and a controller that controls the cleaner; wherein the controller drives the cleaner to perform filter cleaning for removing dust adhering to the air filter.

[0074] With such a configuration, it is possible to provide an air conditioner with improved safety for a case where a flammable refrigerant is used.(Technique 2)

[0075] The air conditioner according to technique 1, wherein the air filter is made of a flame-retardant material.

[0076] With such a configuration, the spread of fire caused by ignition of leaking refrigerant can be suppressed.(Technique 3)

[0077] The air conditioner according to technique 1 or 2, wherein the controller interrupts execution of the filter cleaning in response to receive a signal for interrupting execution of the filter cleaning, and resumes the execution of the filter cleaning or places the filter cleaning to be an executable state after a predetermined cleaning interruption time elapses.

[0078] With such a configuration, the air filter can be reliably cleaned.(Technique 4)

[0079] The air conditioner according to any one of the preceding techniques, wherein the controller continues the filter cleaning even when receiving a signal for interrupting the execution of the filter cleaning in response to an elapsed time since an end of execution of the filter cleaning exceeds a predetermined accumulation time.

[0080] With such a configuration, it is possible to reliably clean the air filter at every predetermined accumulation interval.(Technique 5)

[0081] The air conditioner according to technique 4, further comprising a notifier that notifies a user of information, wherein the controller controls the notifier to notify a warning in response to continuation of the filter cleaning even when a signal for interrupting execution of the filter cleaning is received.

[0082] With such a configuration, it is possible to notify the user that the filter cleaning has been interrupted for a long period.(Technique 6)

[0083] The air conditioner according to any one of the preceding techniques, wherein the cleaner includes a brush that removes dust from the air filter, and the brush is made of a flame-retardant material.

[0084] With such a configuration, it is possible to suppress the spread of fire to the cleaner.(Technique 7)

[0085] The air conditioner according to technique 6, further comprising a dust box for collecting the removed dust.

[0086] With such a configuration, by housing the removed dust in the dust box, the spread of fire to the collected dust can be suppressed.(Technique 8)

[0087] The air conditioner according to claim 7, further comprising a lid disposed in the dust box so as to be openable and closable, wherein in a state where the dust box is closed by the lid, a gap between the dust box and the lid is smaller than an extinction diameter of the refrigerant.

[0088] With such a configuration, the spread of fire to dust collected in the dust box can be suppressed.(Technique 9)

[0089] The air conditioner according to technique 7 or 8, wherein a material forming the dust box is thicker than a material of other components included in the air conditioner.

[0090] With such a configuration, the dust box is less likely to burn, so that the spread of fire to dust can be suppressed.(Technique 10)

[0091] The air conditioner according to any one of techniques 7-9, wherein a material forming the dust box has higher flame retardancy than materials of other components included in the air conditioner.

[0092] With such a configuration, the dust box is less likely to burn, so that the spread of fire to dust can be suppressed.(Technique 11)

[0093] The air conditioner according to any one of techniques 7-10, further comprising a discharger that discharges dust accumulated in the dust box to an outdoor space.

[0094] With such a configuration, since dust is discharged to the outside of the air conditioner, the risk of spread of fire can be reduced.INDUSTRIAL APPLICABILITY

[0095] The present disclosure is applicable to an air conditioner using a flammable refrigerant.EXPLANATION OF REFERENCES

[0096] 10Air Conditioner 20, 20A, 20BIndoor unit 21Casing 23Indoor heat exchanger 24Air filter 25Cleaner 25aBrush 25bRoller 26Controller 27Dust box 28Discharger 29Lid 72Terminal device

Claims

1. An air conditioner using a flammable refrigerant, comprising: an indoor heat exchanger that exchanges heat with indoor air; an air filter through which the indoor air flowing from an indoor space to the indoor heat exchanger passes; a cleaner that cleans the air filter; and a controller that controls the cleaner; wherein the controller drives the cleaner to perform filter cleaning for removing dust adhering to the air filter.

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

3. The air conditioner according to claim 1 or 2, wherein the controller interrupts execution of the filter cleaning in response to receive a signal for interrupting execution of the filter cleaning, and resumes the execution of the filter cleaning or places the filter cleaning to be an executable state after a predetermined cleaning interruption time elapses.

4. The air conditioner according to any one of the preceding claims, wherein the controller continues the filter cleaning even when receiving a signal for interrupting the execution of the filter cleaning in response to an elapsed time since an end of execution of the filter cleaning exceeds a predetermined accumulation time.

5. The air conditioner according to claim 4, further comprising a notifier that notifies a user of information, wherein the controller controls the notifier to notify a warning in response to continuation of the filter cleaning even when a signal for interrupting execution of the filter cleaning is received.

6. The air conditioner according to any one of the preceding claims, wherein the cleaner includes a brush that removes dust from the air filter, and the brush is made of a flame-retardant material.

7. The air conditioner according to claim 6, further comprising a dust box for collecting the removed dust.

8. The air conditioner according to claim 7, further comprising a lid disposed in the dust box so as to be openable and closable, wherein in a state where the dust box is closed by the lid, a gap between the dust box and the lid is smaller than an extinction diameter of the refrigerant.

9. The air conditioner according to claim 7 or 8, wherein a material forming the dust box is thicker than a material of other components included in the air conditioner.

10. The air conditioner according to any one of claims 7-9, wherein a material forming the dust box has higher flame retardancy than materials of other components included in the air conditioner.

11. The air conditioner according to any one of claims 7-10, further comprising a discharger that discharges dust accumulated in the dust box to an outdoor space.

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