Air conditioner

Abstract

An air conditioner using a flammable refrigerant as a refrigerant includes first refrigerant detection sensor (40) and second refrigerant detection sensor (41) that detect refrigerant leakage. Second refrigerant detection sensor (41) is provided with external air blocking unit (45) that blocks external air coming to sensor (42a) of second refrigerant detection sensor (41), and release unit (48) that releases blocking of external air by external air blocking unit (45).

Description

TECHNICAL FIELD

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

[0002] PTL 1 discloses an air conditioner including a detection sensor that detects concentration of a refrigerant in accordance with the preamble of claim 1. PTL 1 describes a configuration in which a plurality of refrigerant detection sensors for detecting leakage of a flammable refrigerant is provided at the same location. In such a configuration, one of two refrigerant detection sensors having a relatively short lifetime is used, and when the refrigerant detection sensor in use fails, the other refrigerant detection sensor is used. This extends the lifetime of a refrigerant detection sensor (see, for example, PTL 1).Citation ListPatent Literature

[0003] PTL 1: Unexamined Japanese Patent Publication No. 2014-224612PROBLEM TO BE SOLVED

[0004] The present invention addresses the problem of the refrigerant detection sensor aging by providing an air conditioner that suppresses degradation in performance of a refrigerant detection sensor caused by aging and improves safety against refrigerant leakage.SUMMARY OF THE INVENTION

[0005] According to the present invention, there is proposed an air conditioner as defined in claim 1. Preferred embodiments are defined in the dependent claims. In detail, it is proposed an air conditioner in which an indoor heat exchanger included in an indoor unit, and an outdoor heat exchanger, a compressor, and a throttle device included in an outdoor unit are connected via a refrigerant pipe and a flammable refrigerant is used as a refrigerant. The air conditioner includes a first refrigerant detection sensor and a second refrigerant detection sensor that detect refrigerant leakage. The second refrigerant detection sensor is provided with an external air blocking unit that blocks external air coming to a sensor of the second refrigerant detection sensor, and a release unit that releases the blocking of external air by external air blocking unit.

[0006] According to the present invention, while the first refrigerant detection sensor is operated, the external air blocking unit blocks the external air, thereby suppressing degradation of the second refrigerant detection sensor caused by aging. Safety against refrigerant leakage can thus be improved.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Fig. 1 is a side cross-sectional view illustrating an indoor unit of an air conditioner according to a first exemplary embodiment. Fig. 2 is a configuration diagram schematically illustrating a refrigerant detection sensor of the air conditioner according to the first exemplary embodiment. Fig. 3 is a block diagram of a control configuration of the air conditioner according to the first exemplary embodiment. Fig. 4 is a chart illustrating an example of degradation determination by a refrigerant detection sensor of the air conditioner according to the first exemplary embodiment. DESCRIPTION OF EMBODIMENT

[0008] At the time when the inventors have arrived at the present invention, there has been a technique for extending the lifetime of a refrigerant detection sensor, as described above, in which a plurality of refrigerant detection sensors for detecting leakage of a flammable refrigerant is provided at the same location and the first one of two refrigerant detection sensors having a relatively short lifetime is used and the second refrigerant detection sensor is used when the first refrigerant detection sensor in use fails.

[0009] However, when a semiconductor refrigerant detection sensor is used with the conventional technique, there is a possibility that erroneous detection is likely to occur in a later operation of a refrigerant detection sensor, that is currently not operated, due to degradation in adsorption capability of a gas filter for various gases, degradation in catalytic activity of a sensor material, or the like. The inventors have found a problem that even when a plurality of refrigerant detection sensors is provided, failure to deliver a sufficient performance by the second refrigerant detection sensor that is used after failure of the first refrigerant detection sensor limits the effect of lifetime extension. The inventors have come to construct the subject matter of the present invention to solve the problem.

[0010] The present invention provides an air conditioner that can suppress degradation of performance of a refrigerant detection sensor caused by aging and improve safety against refrigerant leakage.

[0011] An exemplary embodiment will now be described in detail with reference to the drawings. Unnecessarily detailed description may be omitted. For example, detailed descriptions of already well-known matters and redundant descriptions of substantially the same configuration may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding of those skilled in the art.

[0012] Note that the accompanying drawings and the following description are provided for those skilled in the art to fully understand the present invention, and are not intended to limit the scope of the protection which is limited only by the subject-matter defined in the appended claims.(First exemplary embodiment)

[0013] The first exemplary embodiment will be described below with reference to the drawings.[1-1. Configuration]

[0014] Fig. 1 is a cross-sectional view illustrating an indoor unit of an air conditioner according to the first exemplary embodiment. Fig. 3 is a block diagram of a control configuration of air conditioner 1 according to the first exemplary embodiment.

[0015] As illustrated in Fig. 3, air conditioner 1 includes indoor unit 10. Indoor unit 10 has a configuration illustrated in a cross-sectional view in Fig. 1. Indoor unit 10 includes housing 11 attached to an indoor wall surface.

[0016] Air inlet 12 for sucking indoor air is provided on an upper surface of housing 11. Air outlet 13 through which air is blown into an interior is provided on a lower surface of housing 11. Both air inlet 12 and air outlet 13 are formed entirely across the width direction of housing 11.

[0017] Indoor heat exchanger 14 is accommodated in housing 11. Indoor heat exchanger 14 is formed in a substantially inverted V shape in a side view. Indoor heat exchanger 14 is disposed so as to partition a space between air inlet 12 and air outlet 13 in housing 11. Accordingly, the indoor air sucked from air inlet 12 inevitably passes through indoor heat exchanger 14 to reach air outlet 13.

[0018] Indoor air blower 15 is disposed in the inner side of indoor heat exchanger 14. Indoor air blower 15 is rotatably driven by an air blower drive motor (not illustrated) to suck indoor air from air inlet 12 and to blow out the air that has passed through indoor heat exchanger 14 and is thereby subjected to heat exchange into the interior from air outlet 13.

[0019] Filter 16 is disposed at air inlet 12. Filter 16 is made of a flexible material, and removes dust and the like in the air sucked from air inlet 12.

[0020] Cleaning drive roller 17 is provided in a front portion of the filter 16 to be rotatably driven. Cleaning drive roller 17 is rotationally driven to wind up filter 16 to clean off dust or the like attached to filter 16.

[0021] Left-right wind direction plate 18 for adjusting the left-right wind direction of blown-out air is provided near air outlet 13 to be swingable in the left-right direction. Left-right wind direction plate 18 allows manual adjustment of the wind direction.

[0022] Up-down wind direction plate 19 for adjusting the up-down wind direction of blown-out air is swingably provided below left-right wind direction plate 18. Up-down wind direction plate 19 allows automatic adjustment of the up-down wind direction by a wind direction plate drive motor (not illustrated).

[0023] As illustrated in Fig. 3, air conditioner 1 includes outdoor unit 30. Outdoor unit 30 includes compressor 31, an outdoor heat exchanger (not illustrated), outdoor air blower 32 that sends external air to the outdoor heat exchanger, expansion mechanism (throttle device) 33, and four-way valve 34.

[0024] Outdoor unit 30 and indoor unit 10 are connected by refrigerant pipe 21 (see Fig. 1) to constitute a predetermined refrigeration cycle circuit. A flammable refrigerant is used as a refrigerant that circulates in the refrigeration cycle circuit.

[0025] In the present exemplary embodiment, as illustrated in Fig. 3, indoor unit 10 includes refrigerant shutoff valve 20. Refrigerant shutoff valve 20 performs a closing operation to shut off the refrigerant flowing in refrigerant pipe 21 when refrigerant leakage occurs in indoor unit 10. Refrigerant shutoff valve 20 may be installed in outdoor unit 30.

[0026] First refrigerant detection sensor 40 and second refrigerant detection sensor 41 are disposed in housing 11 to be near indoor heat exchanger 14. First refrigerant detection sensor 40 is a sensor used from the start of use of indoor unit 10, and second refrigerant detection sensor 41 is a sensor used when first refrigerant detection sensor 40 becomes unusable.

[0027] In the present exemplary embodiment, first refrigerant detection sensor 40 is disposed near a connection between refrigerant pipe 21, connecting outdoor unit 30 and indoor unit 10, and indoor unit 10. This is because, in the initial stage of use of the indoor unit 10, refrigerant leakage is more likely to occur at the connection point between indoor heat exchanger 14 and refrigerant pipe 21 than at other places.

[0028] Second refrigerant detection sensor 41 is disposed near a bending position where refrigerant pipe 21 in indoor heat exchanger 14 turns around. This is because the bending position is where refrigerant leakage due to degradation caused by aging of refrigerant pipe 21 of indoor heat exchanger 14 is likely to occur.

[0029] By disposing first refrigerant detection sensor 40 and second refrigerant detection sensor 41 as described above, first refrigerant detection sensor 40 can detect refrigerant leakage at the initial use of indoor unit 10, and second refrigerant detection sensor 41 can detect refrigerant leakage due to degradation of indoor unit 10 caused by aging.

[0030] Second refrigerant detection sensor 41 may be installed at the same location as first refrigerant detection sensor 40. In this case, when first refrigerant detection sensor 40 becomes unusable and detection of refrigerant leakage is switched to that by second refrigerant detection sensor 41, detection of refrigerant leakage can be performed by second refrigerant detection sensor 41 under the same condition as that of first refrigerant detection sensor 40. This suppresses happening of a detection error due to the difference between locations of installation. In the present exemplary embodiment, the same location means that locations are within such a range that the surrounding conditions of first refrigerant detection sensor 40 and second refrigerant detection sensor 41 are the same so that refrigerant leakage can be detected under the same condition by first refrigerant detection sensor 40 and second refrigerant detection sensor 41.

[0031] Fig. 2 is a configuration diagram illustrating a schematic configuration of first refrigerant detection sensor 40 and second refrigerant detection sensor 41.

[0032] As illustrated in Fig. 2, each of first refrigerant detection sensor 40 and second refrigerant detection sensor 41 includes predetermined sensor board 42. Sensor 42a including a semiconductor is mounted on sensor board 42. Substantially cylindrical sensor case 43 covering sensor 42a is attached so as to encircle sensor 42a. Mesh-liked opening 44 is formed at a distal end of sensor case 43. This allows sensor 42a to detect leaked refrigerant that has entered from opening 44.

[0033] It is necessary to heat sensor 42a at a predetermined temperature to operate sensor 42a. Therefore, a heater (not illustrated) is disposed near sensor 42a.

[0034] Second refrigerant detection sensor 41 includes external air blocking unit 45 that closes opening 44. External air blocking unit 45 includes, for example, lid member 46 that closes opening 44, elastic member 47 such as a spring that biases lid member 46 and opening 44 to separate lid member 46 and opening 44 from each other, and a lid holding member (not illustrated) that holds lid member 46 so as lid member 46 to close opening 44. External air blocking unit 45 includes a release unit (releasing mechanism) 48 that releases external air blocking unit 45.

[0035] The present exemplary embodiment illustrates a structure in which the lid holding member of external air blocking unit 45 keeps lid member 46 to be held on sensor case 43. The lid holding member holds lid member 46 on sensor case 43 by, for example, a resin that melts at a predetermined temperature. In this case, release unit 48 includes a heater or the like that melts the resin. When the lid holding member of external air blocking unit 45 has a structure in which, for example, lid member 46 is engaged with a holding claw or the like to be held on sensor case 43, release unit 48 includes a solenoid or the like that electrically releases the engagement of the holding claw.

[0036] As another configuration of release unit 48, for example, a structure in which no elastic member 47 is provided and lid member 46 is electrically openable may be adopted. Alternatively, for example, it may be configured that lid member 46 is made of shape-memory metal that remembers the state in which lid member 46 and opening 44 are separated from each other, and opening 44 is opened by heating lid member 46 to deform by release unit 48 such as a heater.

[0037] When the lid holding member of external air blocking unit 45 is released by release unit 48, lid member 46 moves by the elastic force of elastic member 47 to a place remote from sensor case 43. Accordingly, refrigerant leakage can be detected through opening 44 of sensor case 43.

[0038] External air blocking unit 45 may include a moisture-proof material in the inner side of lid member 46. With this, moisture that may promote degradation of second refrigerant detection sensor 41 in a non-use state can be removed. Degradation of second refrigerant detection sensor 41 can thus be suppressed.

[0039] Lid member 46 of external air blocking unit 45 may be made of a material that shields light and heat. With this, light and heat that may promote degradation of second refrigerant detection sensor 41 in a non-use state can be shielded. Degradation of second refrigerant detection sensor 41 can thus be suppressed.

[0040] Next, a control configuration of air conditioner 1 of the first exemplary embodiment will be described.

[0041] Fig. 3 is a block diagram illustrating the control configuration of the present exemplary embodiment.

[0042] As illustrated in Fig. 3, indoor unit 10 includes controller 50. Controller 50 controls devices of air conditioner 1. Controller 50 includes a processor and a memory. The control by controller 50 is performed by the processor executing a program stored in the memory. The controller includes timer 51. First refrigerant detection sensor 40 and second refrigerant detection sensor 41 are connected to controller 50.

[0043] Controller 50 includes communication unit 52. Communication unit 52 can communicate with remote controller 53 operated by a user. That is, by the user operating remote controller 53, controller 50 controls the driving of compressor 31, outdoor air blower 32, expansion mechanism 33, and four-way valve 34 of outdoor unit 30, and of indoor air blower 15 and up-down wind direction plate 19 of indoor unit 10 based on a set temperature input from remote controller 53.

[0044] Controller 50 controls refrigerant shutoff valve 20 to perform a closing operation when first refrigerant detection sensor 40 or second refrigerant detection sensor 41 detects refrigerant leakage.

[0045] Controller 50 counts the drive time of first refrigerant detection sensor 40 by timer 51 of controller 50. For example, controller 50 counts the drive time of first refrigerant detection sensor 40 until the drive time reaches five years, which is the lifetime of first refrigerant detection sensor 40. When the drive time of first refrigerant detection sensor 40 reaches five years, controller 50 drives release unit 48 to release lid member 46. This enables second refrigerant detection sensor 41 to detect refrigerant leakage.

[0046] Controller 50 determines degradation of first refrigerant detection sensor 40 based on the output of first refrigerant detection sensor 40.

[0047] Fig. 4 is a chart illustrating an example of degradation determination of first refrigerant detection sensor 40. As illustrated in Fig. 4, of first refrigerant detection sensor 40 at the time of delivery, the sensor output increases in proportion to the concentration of refrigerant from 0 point. In this case, controller 50 activates an alarm indicating refrigerant leakage when the sensor output takes a value corresponding to a leaked refrigerant concentration from 1 / 100 LFL (LFL: minimum flammability concentration) to 1 / 4 LFL.

[0048] Meanwhile, when first refrigerant detection sensor 40 has degraded, the sensor output tends to be high compared to the sensor output at the time of delivery. Therefore, controller 50 performs degradation determination using a degradation determination threshold set for the sensor output at 0 point. Specifically, for example, controller 50 determines that the sensor has degraded when the sensor output at 0 point exceeds the degradation determination threshold and the sensor output continues to exceed the degradation determination threshold for a predetermined time or more, for example, 24 hours or more. The reason why the sensor is determined to be degraded when the sensor output continues to exceed the degradation determination threshold for a predetermined time or more (for example, 24 hours or more) is explained below. The sensor output changes by some degree due to a daily temperature cycle, but it is considered that the sensor output continuously exceeding the degradation determination threshold for 24 hours is not due to the effect of the daily temperature cycle.

[0049] The degradation determination threshold for determining degradation of the sensor is set to a value lower than a sensor output at which the alarm of refrigerant leakage is activated. With this setting, an erroneous alarm activation made by the rise of the sensor output due to degradation of the sensor can be suppressed.[1-2. Operation]

[0050] Next, an operation of air conditioner 1 of the first exemplary embodiment will be described.

[0051] In the present exemplary embodiment, in air conditioner 1 which has been installed, first refrigerant detection sensor 40 is operated, and controller 50 determines whether refrigerant leakage has occurred based on an output value of first refrigerant detection sensor 40. Controller 50 counts the drive time after installation of first refrigerant detection sensor 40 by timer 51.

[0052] Controller 50 drives compressor 31, outdoor air blower 32, expansion mechanism 33, four-way valve 34, and indoor air blower 15 to perform cooling and heating operations according to the indoor temperature set by remote controller 53.

[0053] Controller 50 monitors for refrigerant leakage in indoor unit 10 by first refrigerant detection sensor 40, and when refrigerant leakage is detected by first refrigerant detection sensor 40 controls refrigerant shutoff valve 20 to perform a closing operation.

[0054] While first refrigerant detection sensor 40 is monitoring for refrigerant leakage in indoor unit 10, second refrigerant detection sensor 41 is not operated. At this time, since external air blocking unit 45 is shutting off the contact between second refrigerant detection sensor 41 and the outside air, degradation of second refrigerant detection sensor 41 caused by aging while second refrigerant detection sensor 41 is not operated can be suppressed.

[0055] When controller 50 determines by timer 51 of controller 50 that the drive time of first refrigerant detection sensor 40 has reached five years, controller 50 drives release unit 48 of second refrigerant detection sensor 41 to release lid member 46, thereby enabling second refrigerant detection sensor 41 to detect refrigerant leakage.

[0056] Controller 50 determines degradation of first refrigerant detection sensor 40 based on the output of first refrigerant detection sensor 40. A degradation determination threshold for a sensor output at 0 point is previously set in controller 50. Controller 50 determines that first refrigerant detection sensor 40 has degraded when the sensor output at 0 point exceeds the degradation determination threshold and the sensor output continues to exceed the degradation determination threshold for a predetermined time or more (for example, 24 hours or more). When controller 50 determines that first refrigerant detection sensor 40 has degraded, controller 50 drives release unit 48 to release lid member 46 of second refrigerant detection sensor 41, thereby enabling second refrigerant detection sensor 41 to detect refrigerant leakage.

[0057] The earlier one among switching from first refrigerant detection sensor 40 to second refrigerant detection sensor 41 based on a count value of accumulated drive time by timer 51 of first refrigerant detection sensor 40 and switching from first refrigerant detection sensor 40 to second refrigerant detection sensor 41 based on degradation determination by first refrigerant detection sensor 40 is prioritized.

[0058] That is, when it is determined by degradation determination that first refrigerant detection sensor 40 has degraded before the count value of the drive time by timer 51 reaches five years, switching from first refrigerant detection sensor 40 to second refrigerant detection sensor 41 is performed based on the degradation determination.

[0059] It may be configured that, when switching from first refrigerant detection sensor 40 to second refrigerant detection sensor 41 is performed by the count value of accumulated drive time counted by timer 51 reaching the predetermined value or by the degradation determination indicating degradation, controller 50 notifies remote controller 53 or a maintenance management company by sending a notification that indicates that driving of first refrigerant detection sensor 40 has been stopped and that switching to second refrigerant detection sensor 41 has been performed.

[0060] It may be configured that, after completion of switching from first refrigerant detection sensor 40 to second refrigerant detection sensor 41, controller 50 performs degradation determination for second refrigerant detection sensor 41.

[0061] In this case, when determining that both first refrigerant detection sensor 40 and second refrigerant detection sensor 41 have degraded, controller 50 determines that air conditioner 1 can no longer be used, and controls refrigerant shutoff valve 20 to perform a closing operation to make air conditioner 1 unusable. Accordingly, safety against refrigerant leakage can be improved.

[0062] As described above, in air conditioner 1 of the present exemplary embodiment, indoor heat exchanger 14 included in indoor unit 10 and the outdoor heat exchanger, the compressor, and the throttle device included in outdoor unit 30 are connected via refrigerant pipe 21, and a flammable refrigerant is used as a refrigerant. Air conditioner 1 further includes first refrigerant detection sensor 40 and second refrigerant detection sensor that detect refrigerant leakage. The second refrigerant detection sensor is provided with external air blocking unit 45 that blocks external air coming to sensor 42a of second refrigerant detection sensor 41, and release unit 48 that releases blocking of external air by external air blocking unit 45.

[0063] Accordingly, while first refrigerant detection sensor 40 is operated, external air blocking unit 45 blocks the external air, thereby suppressing degradation of second refrigerant detection sensor 41 caused by aging. Therefore, erroneous detection due to degradation caused by aging is suppressed when second refrigerant detection sensor 41 is operated. Therefore, refrigerant leakage can be appropriately detected, and safety against refrigerant leakage can be improved.

[0064] First refrigerant detection sensor 40 and second refrigerant detection sensor 41 may be installed at the same location. In this case, when switching from detection by first refrigerant detection sensor 40 to detection by second refrigerant detection sensor 41 is performed, detection of refrigerant leakage can be performed using second refrigerant detection sensor 41 under the same condition as that of first refrigerant detection sensor 40. This suppresses happening of a detection error due to the difference in installed locations.

[0065] In the present exemplary embodiment, first refrigerant detection sensor 40 is installed near the connection of refrigerant pipe 21 connecting indoor unit 10 and outdoor unit 30. Second refrigerant detection sensor 41 is disposed near the bending position of refrigerant pipe 21 of indoor heat exchanger 14. This enables first refrigerant detection sensor 40 to appropriately detect refrigerant leakage at the initial use of indoor unit 10. This also enables second refrigerant detection sensor 41 to appropriately detect refrigerant leakage due to degradation of refrigerant pipe 21 by aging.

[0066] The present exemplary embodiment includes controller 50 to which sensor outputs of first refrigerant detection sensor 40 and second refrigerant detection sensor 41 are input. When determining that first refrigerant detection sensor exceeds the degradation determination threshold for a predetermined time or more (for example, 24 hours or more), controller 50 operates release unit 48 to remove external air blocking unit 45, and switches to refrigerant leakage monitoring using second refrigerant detection sensor. The degradation determination threshold is set to a value lower than a sensor output at which an alarm is activated by first refrigerant detection sensor 40 detecting refrigerant leakage.

[0067] This enables performing degradation determination by first refrigerant detection sensor 40. In addition, erroneous detection of refrigerant leakage made by using degraded first refrigerant detection sensor 40 can be avoided, thereby suppressing erroneous detection due to degradation of first refrigerant detection sensor 40 caused by aging. Safety against refrigerant leakage can thus be improved.

[0068] In the present exemplary embodiment, controller 50 includes timer 51. Controller 50 counts the drive time of first refrigerant detection sensor 40 by timer 51. When determining that the drive time of first refrigerant detection sensor 40 has reached the predetermined drive time, controller 50 operates release unit 48 to remove external air blocking unit 45 and switches to refrigerant leakage monitoring using second refrigerant detection sensor.

[0069] This enables suppressing erroneous detection caused by using first refrigerant detection sensor 40 that has reached its end of lifetime. Safety against refrigerant leakage can thus be improved.

[0070] In the present exemplary embodiment, when determining that both first refrigerant detection sensor 40 and second refrigerant detection sensor 41 have degraded, controller 50 controls refrigerant shutoff valve 20 provided on refrigerant pipe 21 directed to indoor unit 10 to perform a closing operation.

[0071] This makes air conditioner 1 unusable, and safety against refrigerant leakage can be improved.(Other exemplary embodiments)

[0072] The first exemplary embodiment has been described above as an example of the technique disclosed in the present application. However, the techniques in the present disclosure are not limited to the above exemplary embodiments, and can also be applied to exemplary embodiments in which change, substitution, addition, omission, and the like are made. Furthermore, new exemplary embodiments can be made by combining components described in the first exemplary embodiment.

[0073] For example, first refrigerant detection sensor 40 and second refrigerant detection sensor 41 are generally configured by inserting and connecting a pin of sensor board 42 to a connector provided on a control board.

[0074] In this case, an insulating film or the like may be inserted at a connection between sensor board 42 and the control board of second refrigerant detection sensor 41 to insulate sensor board 42. This prevents sensor board 42 from being energized, and sensor board 42 is blocked from external air by external air blocking unit 45. Therefore, second refrigerant detection sensor 41 can be kept in a state substantially the same as the state at the time of delivery.

[0075] In this configuration, it may be configured that a notification is given to remove an insulating film when first refrigerant detection sensor 40 has reached its end of lifetime or is determined to be degraded by aging.INDUSTRIAL APPLICABILITY

[0076] As described above, the air conditioner according to the present invention can suppress degradation in performance due to degradation of a refrigerant detection sensor caused by aging and improve safety against refrigerant leakage, and thus can be suitably used for various air conditioners.REFERENCE MARKS IN THE DRAWINGS

[0077] 1air conditioner 10indoor unit 11housing 12air inlet 13air outlet 14indoor heat exchanger 15indoor air blower 16filter 17cleaning drive roller 18left-right wind direction plate 19up-down wind direction plate 20refrigerant shutoff valve 21refrigerant pipe 30outdoor unit 31compressor 32outdoor air blower 33expansion mechanism (throttle device) 34four-way valve 40first refrigerant detection sensor 41second refrigerant detection sensor 42sensor board 42asensor 43sensor case 44opening 45external air blocking unit 46lid member 47elastic member 48release unit 50controller 51timer 52communication unit 53remote controller

Claims

1. An air conditioner (1) comprising: an indoor unit (10) including an indoor heat exchanger (14); an outdoor unit (30) including an outdoor heat exchanger, a compressor (31), and a throttle device (33); a refrigerant pipe (21) connecting the indoor heat exchanger (14), the outdoor heat exchanger, the compressor (31), and the throttle device (33) together; and a flammable refrigerant being used as a refrigerant, wherein the air conditioner (1) includes a first refrigerant detection sensor (40) and a second refrigerant detection sensor (41) each including a sensor that is configured to detect refrigerant leakage, characterized in that the second refrigerant detection sensor (41) includes an external air blocking unit (45) that blocks external air coming to the sensor of the second refrigerant detection sensor (41), and a release unit (48) that releases the blocking of external air by the external air blocking unit (45), the air conditioner (1) further comprising a controller (50) to which sensor outputs of the first refrigerant detection sensor (40) and the second refrigerant detection sensor (41) are input, wherein the controller (50) is configured to operate the release unit (48), when an output of the first refrigerant detection sensor (40) is determined to exceed a sensor degradation determination threshold for a predetermined time or more, to remove the external air blocking unit (45) and switch to refrigerant leakage detection using the second refrigerant detection sensor (41), and the sensor degradation determination threshold is set to a value lower than a sensor output at which an alarm is activated by the first refrigerant detection sensor (40) detecting refrigerant leakage.

2. The air conditioner (1) according to claim 1, wherein the first refrigerant detection sensor and the second refrigerant detection sensor are disposed at a same location.

3. The air conditioner (1) according to claim 1, wherein the first refrigerant detection sensor (40) is disposed near a connection between the indoor unit (10) and the refrigerant pipe (21) that connects the indoor unit and the outdoor unit (30), and the second refrigerant detection sensor (41) is disposed near a bending position of the refrigerant pipe (21) of the indoor heat exchanger (14).

4. The air conditioner (1) according to any one of claims 1 to 3, wherein the controller (50) includes a timer (51), and the controller (50) is configured to count a drive time of the first refrigerant detection sensor (40) by the timer (51), and, when determining that the drive time of the first refrigerant detection sensor has reached a predetermined drive time, operate the release unit (48) to remove the external air blocking unit (45) and switch to refrigerant leakage detection using the second refrigerant detection sensor (41).

5. The air conditioner (1) according to any one of claims 1 to 4, wherein a moisture-proof material is disposed in the external air blocking unit (45).

6. The air conditioner (1) according to any one of claims 1 to 5, wherein the external air blocking unit (45) includes a material that shields light and heat.

7. The air conditioner (1) according to any one of claims 1 to 6, further comprising a refrigerant shutoff valve (20) provided on the refrigerant pipe (21) directed to the indoor unit (10), wherein the controller (50) controls the refrigerant shutoff valve (20) to perform a closing operation when determining that both of the first refrigerant detection sensor (40) and the second refrigerant detection sensor (41) have degraded.

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