Air conditioner

Abstract

To provide an air conditioner that uses a combustible refrigerant, and in which if the combustible refrigerant is leaked into a room, an explosion of the leaked combustible refrigerant is restrained.SOLUTION: A floor type air conditioner 10 comprises: a case 72 arranged in a room, and comprising a flow passage including a suction port 72c, a lower discharge port 72b provided in a lower part, and an upper discharge port 72a located at a higher position than the lower discharge port 72b; a fan 24 for generating a flow of air in the flow passage; a heat exchanger 22 inside which a combustible refrigerant heavier than the air flows, and for exchanging heat between the combustible refrigerant and the air in the flow passage; and a gas sensor 82 for detecting the gas concentration of the combustible refrigerant. When the gas sensor 82 detects the gas concentration exceeding a first concentration, a refrigerant agitation operation for agitating the combustible refrigerant in the room by discharging a larger amount of the air from the lower discharge port 72b than that from the upper discharge port 72a is executed until the gas concentration falls below a second concentration lower than the first concentration.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Conventionally, air conditioners that use a flammable refrigerant to perform indoor air conditioning have been known, as described in Patent Document 1, for example. The air conditioner described in Patent Document 1 is configured to discharge the leaked flammable refrigerant to the outside of the room if a leak of the flammable refrigerant occurs inside the indoor unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-324928 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, as described in Patent Document 1, in the case of an indoor air conditioner that uses a flammable refrigerant, there is a possibility that the flammable refrigerant may leak not only into the indoor unit but also into the room.

[0005] Therefore, an object of the present disclosure is to prevent explosion of leaked flammable refrigerant in the unlikely event that flammable refrigerant leaks into a room in an air conditioner that uses the flammable refrigerant. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, according to one aspect of the present invention, A floor-standing air conditioner, a housing arranged indoors and including a flow path including an intake port, a lower outlet provided at a lower portion, and an upper outlet located at a higher position than the lower outlet; a fan that generates, within the flow path, air flows from the intake port toward each of the upper and lower outlets; a heat exchanger through which a flammable refrigerant heavier than air flows and which exchanges heat between the flammable refrigerant and the air in the flow path; a gas sensor for detecting the gas concentration of the flammable refrigerant; When the gas sensor detects a gas concentration exceeding a first concentration, an air conditioner is provided which performs a refrigerant stirring operation in which a larger amount of air is blown out of the lower outlet compared to the upper outlet to stir the flammable refrigerant in the room until the gas concentration falls below a second concentration lower than the first concentration. [Effects of the Invention]

[0007] According to the present disclosure, in the event that flammable refrigerant leaks into a room in an air conditioner that uses a flammable refrigerant, explosion of the leaked flammable refrigerant can be suppressed. [Brief explanation of the drawings]

[0008] [Figure 1] Schematic diagram of an air conditioner according to a first embodiment of the present disclosure. [Figure 2] Schematic front view of an indoor unit of an air conditioner [Figure 3] Schematic diagram of ventilation equipment in an air conditioner [Figure 4] Block diagram showing the control system of an air conditioner [Figure 5] Timing chart showing the flow of control including refrigerant stirring operation [Figure 6] Schematic diagram of an indoor unit of an air conditioner in refrigerant mixing operation [Figure 7] Schematic diagram of an indoor unit of an air conditioner according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] An air conditioner according to one aspect of the present invention is a floor-standing air conditioner, and is arranged indoors. The air conditioner includes a housing having a flow path including an air intake, a lower air outlet provided at a lower portion, and an upper air outlet located at a higher position than the lower air outlet; a fan that generates air flows in the flow path from the air intake toward each of the upper and lower air outlets; The heat exchanger has a flammable refrigerant that is heavier than air flowing inside and exchanging heat between the flammable refrigerant and the air in the flow path, and a gas sensor that detects the gas concentration of the flammable refrigerant.When the gas sensor detects a gas concentration that exceeds a first concentration, a refrigerant stirring operation is performed in which a larger amount of air is blown out from the lower outlet than from the upper outlet to stir the flammable refrigerant in the room until the gas concentration decreases and exceeds a second concentration that is lower than the first concentration.

[0010] According to this aspect, in an air conditioner that uses a flammable refrigerant, if the flammable refrigerant leaks into the room, explosion of the leaked flammable refrigerant can be suppressed.

[0011] For example, the gas sensor may be provided near the lower outlet.

[0012] For example, the air conditioner may further include an upper louver that opens and closes the upper outlet and a lower louver that opens and closes the lower outlet. In this case, when the gas sensor detects a gas concentration that exceeds the first concentration, the upper louver keeps the upper outlet closed, and the lower louver keeps the lower outlet open, until the gas concentration decreases and exceeds the second concentration.

[0013] For example, when the gas concentration detected by the gas sensor falls below the second concentration, the air conditioner may be completely stopped.

[0014] For example, the air conditioner may further include an alarm that issues an alarm about leakage of the flammable refrigerant when the gas sensor detects a gas concentration that exceeds the first concentration.

[0015] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0016] (Embodiment 1) Fig. 1 is a schematic diagram of an air conditioner according to a first embodiment of the present disclosure, and Fig. 2 is a schematic front view of an indoor unit of the air conditioner.

[0017] 1 and 2, an air conditioner 10 according to the first embodiment has an indoor unit 20 arranged in a room Rin to be air-conditioned, and an outdoor unit 30 arranged in an outdoor Rout. Note that the XYZ Cartesian coordinate system shown in the figures is intended to facilitate understanding of the embodiments of the present disclosure and does not limit the embodiments of the present disclosure. The X-axis and Y-axis directions indicate the horizontal direction, and the Z-axis direction indicates the vertical direction.

[0018] The indoor unit 20 is provided with an indoor heat exchanger 22 that exchanges heat with the indoor air A1, and an indoor fan 24 that draws the indoor air A1 into the indoor unit 20 and blows the indoor air A1 into the room Rin after heat exchange with the indoor heat exchanger 22.

[0019] 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 the outdoor air A2 into the outdoor unit 30 and blows the outdoor air A2 out to the outdoor Rout after exchanging heat with the outdoor heat exchanger 32. 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 22 and the outdoor heat exchanger 32.

[0020] The indoor heat exchanger 22, the outdoor heat exchanger 32, the compressor 36, the expansion valve 38, and the four-way valve 40 are each connected by a refrigerant pipe through which a refrigerant flows. In cooling operation and dehumidification operation (weak cooling operation), the air conditioner 10 executes a refrigeration cycle in which the refrigerant flows from the compressor 36 through the four-way valve 40, the outdoor heat exchanger 32, the expansion valve 38, and the indoor heat exchanger 22 in that order, before returning to the compressor 36. In heating operation, the air conditioner 10 executes a refrigeration cycle in which the refrigerant flows from the compressor 36 through the four-way valve 40, the indoor heat exchanger 22, the expansion valve 38, and the outdoor heat exchanger 32 in that order, before returning to the compressor 36.

[0021] In addition to air conditioning operation using a refrigeration cycle, the air conditioner 10 also performs air conditioning operation in which outdoor air A2 is supplied to the room Rin and air conditioning operation in which indoor air A1 is exhausted to the outdoor Rout. To achieve this, the air conditioner 10 has a ventilation device 50. In the case of the first embodiment, the ventilation device 50 is provided in the outdoor unit 30.

[0022] FIG. 3 is a schematic diagram of a ventilation system.

[0023] As shown in FIG. 3, the ventilation device 50 includes an absorbent material 52 therein through which the outdoor air A2 passes.

[0024] The absorbent material 52 is a member through which air can pass and which collects moisture from the air passing through it or adds moisture to the air passing through it. In this embodiment, the absorbent material 52 is disk-shaped and rotates around a rotation center line C1 that passes through the center of the absorbent material 52. The absorbent material 52 is rotationally driven by a motor 54.

[0025] The absorbent 52 is made of a polymeric adsorbent, such as cross-linked sodium polyacrylate, that adsorbs moisture from the air. Compared to adsorbents such as silica gel and zeolite, polymeric adsorbents absorb a larger amount of moisture per unit volume, can desorb moisture at low heating temperatures, and can retain moisture for a long period of time.

[0026] Inside the ventilation device 50, there are provided a first flow path P1 and a second flow path P2 through which the outdoor air A2 flows, each passing through an absorbent material 52. That is, the absorbent material 52 is arranged so that a portion thereof is located in the first flow path P1 and another portion thereof is located in the second flow path P2. When the absorbent material 52 is rotated by the motor 54, the portion of the absorbent material 53 located in one of the first and second flow paths P1, P2 moves to the other. Furthermore, inside the ventilation device 50, there is provided a third flow path P3, both ends of which are connected to different portions of the first flow path P1.

[0027] The first flow path P1 is a flow path through which outdoor air A2 flows toward the indoor unit 20. The outdoor air A2 flowing through the first flow path P1 is supplied into the indoor unit 20 via a ventilation duct 56.

[0028] A heater 58 that heats the outside air A2 is provided in a portion of the first flow path P1 upstream of the absorbent material 52. In this specification, the terms "upstream" and "downstream" are used with respect to the flow of air.

[0029] The heater 58 is preferably a PTC (Positive Temperature Coefficient) heater, which increases electrical resistance as current flows and the temperature rises, thereby preventing excessive increases in heating temperature. In the case of heaters using nichrome wire or carbon fiber, the heating temperature (surface temperature) continues to rise as current continues to flow, so the temperature must be monitored. In the case of a PTC heater, the heater itself adjusts the heating temperature within a certain temperature range, eliminating the need to monitor the heating temperature.

[0030] The first flow path P1 is provided with a fan 60 that generates a flow of outdoor air A2 toward the indoor unit 20. In the present embodiment, the fan 60 is disposed downstream of the absorbent material 52. When the fan 60 is operated, the outdoor air A2 flows into the first flow path P1 from the outdoor Rout and passes through the absorbent material 52.

[0031] Furthermore, the first flow path P1 is provided with a damper device 62 for distributing the outdoor air A2 flowing through the first flow path P1 to the indoor Rin (i.e., the indoor unit 20) or the outdoor Rout. That is, the first flow path P1 branches toward the indoor Rin and the outdoor Rout, and the damper device 62 is disposed at the branching point. The damper device 62 is disposed downstream of the fan 60. The outdoor air A2 distributed to the indoor unit 20 by the damper device 62 enters the indoor unit 20 via the ventilation duct 56 and is blown out into the indoor Rin by the indoor fan 24.

[0032] Furthermore, a damper device 64 different from the damper device 62 is provided in the first flow path P1. In the present embodiment, the damper device 64 is disposed between the absorber 52 and the fan 60. As will be described in detail later, the damper device 64 is provided for exhaust ventilation, and selectively opens and closes the first flow path P1.

[0033] Furthermore, a third flow path P3 is connected to the first flow path P1. The third flow path P3, which will be described in detail later, is a flow path for exhaust ventilation, and connects a portion of the first flow path P1 between the fan 60 and the damper device 64 with a portion of the first flow path P1 downstream of the damper device 62. A damper device 66 is provided in the third flow path P3. The damper device 66, which will be described in detail later, is provided for exhaust ventilation and selectively opens and closes the third flow path P3.

[0034] The second flow path P2 is a flow path through which the outdoor air A2 flows. Unlike the outdoor air A2 flowing through the first flow path P1, the outdoor air A2 flowing through the second flow path P2 does not head toward the indoor unit 20. In other words, the second flow path P2 is a flow path independent from the first flow path P1. The outdoor air A2 flowing through the second flow path P2 passes through the absorbent material 52 and then flows out to the outdoor Rout.

[0035] A fan 68 that generates a flow of outdoor air A2 is provided in the second flow path P2. In the present embodiment, the fan 68 is disposed downstream of the absorbent material 52. When the fan 68 is operated, the outdoor air A2 flows from the outdoor Rout into the second flow path P2, passes through the absorbent material 52, and then flows out to the outdoor Rout.

[0036] The ventilation device 50 selectively performs ventilation operation, humidification operation, and dehumidification operation by selectively using the absorbent material 52 (motor 54), heater 58, fan 60, damper devices 62, 64, 66, and fan 68. The ventilation operation includes an air supply ventilation operation and an exhaust ventilation operation.

[0037] The supply ventilation operation is an air conditioning operation in which the outdoor air A2 is supplied to the room Rin (i.e., the indoor unit 20). During the supply ventilation operation, the motor 54 continues to rotate the absorbent material 52. The heater 58 is in the OFF state and does not heat the outdoor air A2. The fan 60 is in the ON state, thereby causing the outdoor air A2 to flow through the first flow path P1. The damper device 62 distributes the outdoor air A2 in the first flow path P1 to the indoor unit 20. The damper device 64 is in the open state, thereby causing the outdoor air A2 to flow from the absorbent material 52 toward the fan 60. The damper device 66 is in the closed state, thereby preventing the outdoor air A2 from flowing through the third flow path P3. The fan 68 is in the OFF state, thereby preventing the flow of the outdoor air A2 through the second flow path P2.

[0038] According to this supply ventilation operation, the outdoor air A2 flows into the first flow path P1 and passes through the absorbent material 52 without being heated by the heater 58. The outdoor air A2 that has passed through the absorbent material 52 is distributed to the indoor unit 20 by the damper device 62. The outdoor air A2 that has passed through the damper device 62 and reached the indoor unit 20 via the ventilation duct 56 is blown out into the room Rin by the indoor fan 24. According to this supply ventilation operation, the outdoor air A2 is supplied as is to the room Rin, and the room Rin is supply ventilated.

[0039] The exhaust ventilation operation is an air conditioning operation in which the room air A1 is exhausted to the outdoor Rout. During the exhaust ventilation operation, the motor 54 is in the OFF state, and the absorbent material 52 is not rotating. The heater 58 is in the OFF state. The fan 60 is in the ON state, and the room air A1 passes through the ventilation duct 56 and the third flow path P3 and flows toward the fan 60. The damper device 62 distributes the room air A1 in the first flow path P1 to the outdoor Rout. The damper device 64 is in the closed state, and therefore the room air A1 does not flow toward the absorbent material 52. The damper device 66 is in the open state, and therefore the room air A1 flows toward the fan 60 via the third flow path P3. The fan 68 is in the OFF state, and therefore no flow of the outdoor air A2 is generated in the second flow path P2.

[0040] In this exhaust ventilation operation, when the fan 60 is in the ON state, the room air A1 flows into the portion of the first flow path P1 between the absorbent material 52 and the fan 60 via the ventilation conduit 56 and the third flow path P3. At this time, the damper device 64 is in the closed state, so the room air A1 does not flow toward the absorbent material 52. The room air A1 that has passed through the fan 60 is diverted to the outdoor air Rout by the damper device 62 and discharged to the outdoor air Rout. As a result, the room air Rin is exhausted and ventilated.

[0041] In addition, the third flow path P3 allows the fan 60 to rotate in the same direction during exhaust ventilation operation as during supply ventilation operation. As a result, a sirocco fan can be used as the fan 60.

[0042] The humidification operation is an air conditioning operation that humidifies the outdoor air A2 and supplies the humidified outdoor air A2 to the room Rin (i.e., the indoor unit 20). During the humidification operation, the motor 54 continues to rotate the absorbent material 52. The heater 58 is in an ON state, heating the outdoor air A2. The fan 60 is in an ON state, causing the outdoor air A2 to flow through the first flow path P1. The damper device 62 distributes the outdoor air A2 in the first flow path P1 to the indoor unit 20. The damper device 64 is in an open state, causing the outdoor air A2 to flow from the absorbent material 52 toward the fan 60. The damper device 66 is in a closed state, causing the outdoor air A2 to not flow through the third flow path P3. The fan 68 is in an ON state, causing the outdoor air A2 to flow through the second flow path P2.

[0043] According to this humidification operation, the outdoor air A2 flows into the first flow path P1, is heated by the heater 58, and passes through the absorbent 52. At this time, the heated outdoor air A2 can remove a larger amount of moisture from the absorbent 52 than when the outdoor air A2 is not heated. As a result, the outdoor air A2 carries a larger amount of moisture. The outdoor air A2 that has passed through the absorbent 52 and carried a larger amount of moisture is distributed to the indoor unit 20 by the damper device 62. The outdoor air A2 that has passed through the damper device 62 and reached the indoor unit 20 via the ventilation duct 56 is blown into the room Rin by the indoor fan 24. According to this humidification operation, the outdoor air A2 carrying a larger amount of moisture is supplied to the room Rin, and the room Rin, i.e., the room air A1, is humidified.

[0044] As moisture is removed by the heated outdoor air A2, the water retention capacity of the absorbent 52 decreases, i.e., the absorbent 52 dries. When the absorbent 52 dries, the outdoor air A2 flowing through the first flow path P1 cannot remove moisture from the absorbent 52. To address this, the absorbent 52 removes moisture from the outdoor air A2 flowing through the second flow path P2. This keeps the water retention capacity of the absorbent 52 approximately constant, allowing the humidification operation to continue.

[0045] The dehumidifying operation is an air conditioning operation in which the outdoor air A2 is dehumidified and the dehumidified outdoor air A2 is supplied to the room Rin (that is, the indoor unit 20). In the dehumidifying operation, the adsorption operation and the regeneration operation are performed alternately.

[0046] The adsorption operation is an operation in which moisture contained in the outdoor air A2 is adsorbed onto the absorbent material 52, thereby dehumidifying the outdoor air A2. During the adsorption operation, the motor 54 continues to rotate the absorbent material 52. The heater 58 is in the OFF state, and does not heat the outdoor air A2. The fan 60 is in the ON state, and thereby the outdoor air A2 flows through the first flow path P1. The damper device 62 distributes the outdoor air A2 in the first flow path P1 to the indoor unit 20. The damper device 64 is in the open state, and thereby the outdoor air A2 flows from the absorbent material 52 toward the fan 60. The damper device 66 is in the closed state, and thereby the outdoor air A2 does not flow through the third flow path P3. The fan 68 is in the OFF state, and thereby no flow of the outdoor air A2 occurs through the second flow path P2.

[0047] According to this adsorption operation, the outdoor air A2 flows into the first flow path P1 and passes through the absorbent 52 without being heated by the heater 58. At this time, the moisture carried in the outdoor air A2 is adsorbed by the absorbent 52. This reduces the amount of moisture carried by the outdoor air A2, i.e., the outdoor air A2 is dried. The outdoor air A2 that has passed through the absorbent 52 and is then distributed to the indoor unit 20 by the damper device 62. The outdoor air A2 that has passed through the damper device 62 and reached the indoor unit 20 via the ventilation duct 56 is then blown into the room Rin by the indoor fan 24. According to this adsorption operation, the dried outdoor air A2 is supplied to the room Rin, and the room Rin is dehumidified.

[0048] As the adsorption operation continues, the amount of water held by the absorbent 52 continues to increase, resulting in a decrease in the absorbent 52's ability to adsorb the moisture contained in the outdoor air A2. In order to recover the adsorption ability, a regeneration operation is performed to regenerate the absorbent 52.

[0049] During regeneration operation, the motor 54 continues to rotate the absorbent material 52. The heater 58 is ON, heating the outdoor air A2. The fan 60 is ON, causing the outdoor air A2 to flow through the first flow path P1. The damper device 62 distributes the outdoor air A2 in the first flow path P1 to the outdoor Rout rather than to the indoor unit 20. The damper device 64 is open, causing the outdoor air A2 to flow from the absorbent material 52 toward the fan 60. The damper device 66 is closed, preventing the outdoor air A2 from flowing through the third flow path P3. The fan 68 is OFF, causing no flow of the outdoor air A2 through the second flow path P2.

[0050] According to this regeneration operation, the outdoor air A2 flows into the first flow path P1, is heated by the heater 58, and passes through the absorbent 52. At this time, the heated outdoor air A2 removes a large amount of moisture from the absorbent 52. As a result, the outdoor air A2 carries a large amount of moisture. At the same time, the water retention capacity of the absorbent 52 decreases, that is, the absorbent 52 dries and its adsorption capacity is regenerated. The outdoor air A2 that has passed through the absorbent 52 and carries a large amount of moisture is diverted by the damper device 62 to the outdoor Rout and discharged to the outdoor Rout. As a result, during the regeneration operation in the dehumidification operation, the outdoor air A2 carrying a large amount of moisture due to the regeneration of the absorbent 52 is not supplied to the indoor Rin.

[0051] By alternately performing the adsorption operation and the regeneration operation in this manner, the adsorption capacity of the absorbent material 52 is maintained, and the dehumidification operation can be carried out continuously.

[0052] The air conditioning operations (cooling operation, dehumidifying operation (weak cooling operation), heating operation) using the refrigeration cycle and the air conditioning operations (ventilation operation (supply ventilation operation, exhaust ventilation operation), humidifying operation, dehumidifying operation) using the ventilation device 50 described above can be performed separately or simultaneously. For example, by simultaneously performing the dehumidifying operation using the refrigeration cycle and the dehumidifying operation using the ventilation device 50, it is possible to dehumidify the room Rin while maintaining a constant room temperature.

[0053] Furthermore, in the intake ventilation operation, humidification operation, and dehumidification operation, the indoor fan 24 rotates to blow the outdoor air A2 into the room Rin. This rotation of the indoor fan 24 draws the room air A1 into the indoor unit 20. Therefore, the outdoor air A2 is mixed with the room air A1 and blown out into the room Rin.

[0054] The air conditioning operation to be performed by the air conditioner 10 is selected by the user. For example, when the user performs a selection operation on the remote controller 70 shown in Fig. 1, the air conditioner 10 performs the air conditioning operation corresponding to that operation. The air conditioner 10 also notifies the user via the remote controller 70 of information related to the air conditioning operation that is currently being performed.

[0055] Up to this point, we have provided an overview of the configuration and operation of the air conditioner 10 according to Embodiment 1. From here on, further features of the air conditioner 10 according to Embodiment 1 will be described.

[0056] 1 and 2, the indoor unit 20 of the air conditioner 10 according to Embodiment 1 is placed on the floor surface FS of the room Rin. In other words, the air conditioner 10 is a floor-standing type.

[0057] As shown in FIGS. 1 and 2 , the indoor unit 20 has a housing 72 that houses the indoor heat exchanger 22 and the indoor fan 24. The housing 72 is provided with a plurality of outlets 72a, 72b for blowing indoor air A1 that has passed through the indoor heat exchanger 22 and / or outdoor air A2 supplied from the ventilation device 50 into the room Rin. The housing 72 is also provided with a plurality of inlet ports 72c for taking the indoor air A1 into the housing 72. That is, a flow path through which air flows is provided within the housing 72, including the outlets 72a, 72b and the inlet ports 72c. In the first embodiment, the flow path is divided into an upstream flow path P4 and a downstream flow path P5, with the indoor heat exchanger 22 sandwiched between them. In the first embodiment, outdoor air A2 from the ventilation device 50 is supplied to the downstream flow path P5.

[0058] Specifically, the air outlet 72a is provided in the upper part of the housing 72. In the first embodiment, this upper air outlet 72a faces diagonally upward, that is, toward the ceiling of the room Rin. Through this upper air outlet 72a, the room air A1 that has passed through the indoor heat exchanger 22 and / or the outdoor air A2 supplied from the ventilation device 50 is blown out from the housing 72 toward the ceiling of the room Rin. In addition, the housing 72 is provided with an upper louver 74 for opening and closing the upper air outlet 72a and for adjusting the airflow direction.

[0059] The air outlet 72b is provided at the bottom of the housing 72, i.e., it is provided at a position lower than the upper air outlet 72a and closer to the floor surface FS. The lower air outlet 72b is oriented horizontally, i.e., oriented along the floor surface FS. The lower air outlet 72b blows the indoor air A1 that has passed through the indoor heat exchanger 22 and / or the outdoor air A2 supplied from the ventilation device 50 out of the housing 72 along the floor surface FS. The housing 72 is also provided with a lower louver 76 for opening and closing the lower air outlet 72b and for adjusting the airflow direction.

[0060] 1 and 2, a plurality of intake ports 72c are provided on both side surfaces of the housing 72 of the indoor unit 20 for taking in indoor air A1 into the housing 72. The indoor air A1 is taken in through the plurality of intake ports 72c into an upstream flow path P4 of the housing 72, which is upstream of the indoor heat exchanger 22. In the first embodiment, the indoor fan 24 is disposed in a downstream flow path P5 of the housing 72, which is in a space downstream of the indoor heat exchanger 22, is independent of the upstream flow path P4, and is connected to the upper and lower outlets 72a, 72b. Therefore, when the indoor fan 24 rotates, an air flow from the intake port 72c toward the upper and lower outlets 72a, 72b is generated in the flow path. Specifically, the indoor air A1 flows into the upstream flow path P4 through the intake port 72c. The inflowing indoor air A1 passes through the indoor heat exchanger 22, and then flows out into the room Rin via the downstream flow path P5 and the upper and lower outlets 72a, 72b.

[0061] In the floor-standing air conditioner 10 equipped with the ventilation function described above, a flammable refrigerant that has a small environmental impact, such as propane, isobutane, ethane, etc., is used as the refrigerant. In particular, a flammable refrigerant such as propane, which is gaseous at room temperature and is heavier than air when in gaseous form, is used.

[0062] If such flammable refrigerant leaks from an air conditioner, it may explode. The "explosion" referred to here refers to a phenomenon that occurs when flammable refrigerant mixes with oxygen and is ignited by an ignition source such as an electrical appliance. Therefore, the air conditioner 10 according to this embodiment is configured to prevent the explosion of the leaked flammable refrigerant in the unlikely event that flammable refrigerant leaks into the indoor Rin. The features that enable this are described below.

[0063] FIG. 4 is a block diagram showing a control system of the air conditioner.

[0064] 4, the air conditioner 10 has a control device 80 that controls air conditioning operation. The control device 80 is, for example, a control circuit board on which a processor such as a CPU is mounted, and is provided in the indoor unit 20.

[0065] The control device 80 controls the compressor 36 and the four-way valve 40 to perform air conditioning operation using a refrigeration cycle, i.e., heating operation or cooling operation. The control device 80 also controls the ventilation device 50 (its motor 54, heater 58, fan 60, damper devices 62, 64, 66, and fan 68) to perform the above-mentioned supply ventilation operation, exhaust ventilation operation, humidification operation, or dehumidification operation.

[0066] The control device 80 is configured to detect the gas concentration of the flammable refrigerant in the room Rin, i.e., in the room air A1. To that end, the air conditioner 10 has a gas sensor 82 and an alarm 84 that alerts the user to the occurrence of a flammable refrigerant leak.

[0067] In the first embodiment, the gas sensor 82 is a sensor that can detect a gaseous flammable refrigerant and output a value (for example, a voltage value) corresponding to the gas concentration.

[0068] The alarm device 84 is a device that notifies the occurrence of a gas leak by a warning sound or a voice message, and is provided, for example, in the housing 72 of the indoor unit 20. The alarm device 84 may also be provided in the remote controller 70.

[0069] In the first embodiment, in order to detect the gas concentration of the flammable refrigerant in the room Rin, the gas sensor 82 is provided in a flow path (P4 or P5) in the housing 72 of the indoor unit 20 through which the room air A1 flows. As a result, during air-conditioning operation, i.e., during operation while the indoor fan 24 is operating, the room air A1 comes into contact with the gas sensor 82. This allows the gas sensor 82 to detect the gas concentration of the flammable refrigerant in the room air A1, i.e., in the room Rin. The detected gas concentration makes it possible to detect leakage of the flammable refrigerant into the room Rin.

[0070] In the first embodiment, as shown in FIG. 1, the gas sensor 82 is provided in a portion of the housing 72 near the lower outlet 72b. This arrangement makes it possible to detect flammable refrigerant even when the air-conditioning operation is stopped, i.e., when the indoor fan 24 is stopped. Specifically, in the first embodiment, the flammable refrigerant is heavier than air and therefore accumulates on the floor surface FS. The gas accumulated on the floor surface FS enters the flow path of the housing 72 through the gap between the opening edge of the lower outlet 72b and the lower louver 76. As a result, the gas sensor 82 can detect the gas concentration of the flammable refrigerant in the room Rin even when the air-conditioning operation is stopped.

[0071] The control device 80 determines whether or not there is a leakage of flammable refrigerant into the room Rin, based on the gas concentration of the flammable refrigerant detected by the gas sensor 82. If it is determined that there is a leakage of flammable refrigerant, the control device 80 executes a refrigerant stirring operation as an operation to suppress explosion of the leaked flammable refrigerant.

[0072] Fig. 5 is a timing chart showing the flow of control, including refrigerant agitation operation, in the air conditioner according to Embodiment 1. Fig. 6 is a schematic diagram of the indoor unit of the air conditioner in the refrigerant agitation operation state. Fig. 5 shows an example of a situation in which the refrigerant agitation operation is started during air conditioning operation.

[0073] 5, when gas sensor 82 detects a gas concentration exceeding a first concentration during air conditioning operation (timing t1), refrigerant agitation operation is initiated. The first concentration is a concentration sufficiently lower than the lower explosion limit concentration of the flammable refrigerant, at which the flammable refrigerant may explode. In consideration of erroneous detection by gas sensor 82, refrigerant agitation operation may be initiated when gas sensor 82 continues to detect a gas concentration exceeding the first concentration for a predetermined period of time.

[0074] When the refrigerant stirring operation starts, the control device 80 sets the rotation speed of the indoor fan 24 to the maximum (MAX). Furthermore, as shown in FIG. 6, the control device 80 controls the upper louver 74 to keep the upper outlet 72a closed, while controlling the lower louver 76 to keep the lower outlet 72b open. This causes the indoor air A1 blown by the indoor fan 24 to be preferentially blown out from the lower outlet 72b. The indoor air A1 blown out from the lower outlet 72b flows along the floor surface FS, blowing away flammable refrigerant that accumulates on the floor surface FS. This prevents the flammable refrigerant from accumulating and becoming highly concentrated, thereby reducing the possibility of an explosion of the flammable refrigerant.

[0075] 5, during the refrigerant agitation operation, the control device 80 continues to warn of a flammable refrigerant leak via the alarm device 84. This allows the user to know that a flammable refrigerant is leaking and that the air conditioner 10 is performing the flammable refrigerant agitation operation. The timing at which the alarm device 84 starts issuing the warning may be the same as the start of the refrigerant agitation operation, or may be delayed.

[0076] As shown in FIG. 5, the compressor 36 continues to operate during the refrigerant stirring operation. That is, the refrigerant stirring operation is performed while air-conditioning operation using the refrigeration cycle is being performed. This is because, in the case of the first embodiment, the compressor 36 is mounted in the outdoor unit 30 installed in the outdoor Rout and does not become an ignition source for flammable refrigerant leaking into the indoor Rin. Alternatively, the compressor 36 may be stopped during the refrigerant stirring operation. In particular, it is preferable to stop the compressor 36 during heating operation. During heating operation, the pressure inside the indoor heat exchanger 22 and the refrigerant piping in the indoor unit 20 becomes high, and therefore, if flammable refrigerant leaks from these, the amount of leakage will be large.

[0077] As shown in Fig. 5, as the refrigerant agitation operation continues, the gas concentration detected by the gas sensor 82 decreases. That is, the flammable refrigerant is dispersed throughout the room Rin, and the gas concentration of the flammable refrigerant in the room Rin decreases. When the gas concentration decreases beyond a second concentration that is lower than the first concentration (timing t2), the control device 80 ends the refrigerant agitation operation. When the refrigerant agitation operation ends, the control device 80 completely shuts down the air conditioner 10.

[0078] Specifically, the indoor fan 24 is stopped. This prevents an explosion of flammable refrigerant caused by the indoor fan 24 (its drive motor) as an ignition source. The compressor 36 is also stopped. This reduces the amount of flammable refrigerant leaking inside the indoor unit 20, i.e., the amount of flammable refrigerant leaking from the indoor heat exchanger 22 or leaking points in the refrigerant piping around it. The upper louvers 74 and lower louvers 76 are also controlled to close the upper outlet 72a and the lower outlet 72b. This prevents flammable refrigerant from leaking from the indoor unit 20 to the room Ain. The alarm 84 is then stopped.

[0079] If the air conditioner 10 is completely stopped after the refrigerant stirring operation is completed, the air conditioner 10 will wait for repairs by a specialist to repair the leaking part of the flammable refrigerant. The air conditioner 10 may be completely stopped so that the user cannot start the air conditioner 10 until the repair is completed.

[0080] According to the first embodiment as described above, in the event that flammable refrigerant leaks into the room in an air conditioner that uses a flammable refrigerant, explosion of the leaked flammable refrigerant can be suppressed.

[0081] Specifically, in the case of the first embodiment, the air conditioner 10 is a so-called floor-standing air conditioner and is provided with a lower outlet 72b capable of blowing air near the floor surface FS. The air blown out from this lower outlet 72b blows away the flammable refrigerant, which is heavier than air, that has leaked from the air conditioner 10 (its indoor unit 20) and accumulated on the floor surface FS, while stirring the flammable refrigerant in the room. This causes the flammable refrigerant that has accumulated in high concentration on the floor surface FS to be dispersed throughout the room. As a result, explosions of flammable refrigerant that has leaked from the indoor unit 20 into the room Rin are suppressed.

[0082] Although the present disclosure has been described with reference to the first embodiment above, the present disclosure is not limited to these embodiments.

[0083] For example, in the case of the above-described first embodiment, as shown in Fig. 5, during the refrigerant agitation operation, the upper outlet 72a is kept closed by the upper louver 74, while the lower outlet 72b is kept open by the lower louver 76. As a result, the indoor air A1 blown by the indoor fan 24 to the indoor fan 24 is preferentially blown out from the lower outlet 72b. However, the method for preferentially blowing out air from the lower outlet 72b is not limited to this.

[0084] FIG. 7 is a schematic diagram of an indoor unit of an air conditioner according to another embodiment.

[0085] 7, an indoor unit 120 of an air conditioner according to another embodiment has a first fan 124A arranged upstream of an upper air outlet 172a of a housing 172, and a second fan 124B arranged upstream of a lower air outlet 172b. The first and second fans 124A and 124B are, for example, crossflow fans.

[0086] When the first and second fans 124A, 124B rotate, indoor air A1 is drawn into the housing 172 through the intake port 172c and passes through the indoor heat exchanger 122. The indoor air A1 that has passed through the indoor heat exchanger 122 is blown out into the room through the upper outlet 172a and the lower outlet 172b.

[0087] According to this indoor unit 120, by independently controlling the first and second fans 124A, 124B, it is possible to independently control the flow rate of air blown out from the upper outlet 172a and the flow rate of air blown out from the lower outlet 172b. Therefore, by setting the rotation speed of the first fan 124A to zero, it is possible to preferentially blow out air from the lower outlet 172b.

[0088] Furthermore, in the case of the first embodiment described above, the air conditioner 10 includes a ventilation device 50 capable of performing an exhaust ventilation operation in which the indoor air A1 is exhausted to the outdoor Rout. The exhaust ventilation operation may be performed immediately after the refrigerant stirring operation has been performed, without completely shutting down the air conditioner 10. That is, the refrigerant stirring operation is performed to reduce the gas concentration of the flammable refrigerant in the indoor air A1, and then the indoor air A1 is exhausted to the outdoor Rout by the exhaust ventilation operation. Therefore, the flammable refrigerant can be exhausted to the outdoor Rout while reducing the risk of an explosion of the flammable refrigerant. In this case, the air conditioner 10 is completely shut down after the exhaust ventilation operation has been performed for a predetermined period of time.

[0089] In other words, the air conditioner according to the embodiment of the present disclosure is, in a broad sense, a floor-standing air conditioner that is arranged indoors and has a housing with a flow path including an intake port, a lower outlet provided at the bottom, and an upper outlet located at a higher position than the lower outlet, a fan that generates an air flow in the flow path from the intake port toward each of the upper and lower outlets, a heat exchanger through which a flammable refrigerant that is heavier than air flows and exchanges heat between the flammable refrigerant and the air in the flow path, and a gas sensor that detects the gas concentration of the flammable refrigerant, and when the gas sensor detects a gas concentration exceeding a first concentration, the air conditioner performs a refrigerant stirring operation in which a larger amount of air is blown out from the lower outlet than from the upper outlet to stir the flammable refrigerant in the room until the gas concentration decreases beyond a second concentration that is lower than the first concentration. [Industrial Applicability]

[0090] The present disclosure is applicable to any floor-standing air conditioner that has a lower air outlet. [Explanation of symbols]

[0091] 10 Air conditioner 22 Heat exchanger (indoor heat exchanger) 24 Fans (Indoor Fans) 72 Cabinet 72a Upper air outlet 72b Lower air outlet 72c intake 82 Gas Sensor

Claims

1. A floor-standing air conditioner, a housing arranged indoors and including a flow path including an intake port, a lower outlet provided at a lower portion, and an upper outlet located at a higher position than the lower outlet; a fan that generates, within the flow path, air flows from the intake port toward each of the upper and lower outlets; a heat exchanger through which a flammable refrigerant heavier than air flows and which exchanges heat between the flammable refrigerant and the air in the flow path; a gas sensor for detecting the gas concentration of the flammable refrigerant; When the gas sensor detects a gas concentration exceeding a first concentration, the air conditioner performs a refrigerant stirring operation in which a larger amount of air is blown out of the lower outlet than the upper outlet to stir the flammable refrigerant in the room until the gas concentration decreases below a second concentration lower than the first concentration.

2. The air conditioner according to claim 1, wherein the gas sensor is provided near the lower outlet.

3. an upper louver that opens and closes the upper air outlet; a lower louver that opens and closes the lower air outlet, The air conditioner of claim 1, wherein when the gas sensor detects a gas concentration exceeding the first concentration, the upper louver keeps the upper outlet closed while the lower louver keeps the lower outlet open until the gas concentration decreases below the second concentration.

4. The air conditioner according to claim 1 , wherein the air conditioner is completely stopped when the gas concentration detected by the gas sensor falls below the second concentration.

5. The air conditioner according to claim 1, further comprising an alarm that issues an alarm about a leak of the flammable refrigerant when the gas sensor detects a gas concentration exceeding the first concentration.

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