JP4639451B2 - Air conditioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air conditioner, and more particularly to an air conditioner using a flammable refrigerant (including a slightly flammable refrigerant; the same applies throughout this specification).
[0002]
[Background Art and Problems to be Solved by the Invention]
In recent years, an air conditioner using a combustible refrigerant such as R32 has been proposed as an alternative refrigerant to replace R22. In an air conditioner that uses this type of flammable refrigerant, the flammable refrigerant leaks to the outside from the refrigerant piping (connecting piping) connected to the indoor unit or to the indoor unit, causing a fire, oxygen deficiency, or thermal decomposition. There is concern about accidents that generate toxic gases (hereinafter referred to as “fire accidents”).
[0003]
However, in the conventional air conditioner, it cannot be said that sufficient measures are taken when the combustible refrigerant leaks.
[0004]
Accordingly, an object of the present invention is to provide an air conditioner that can prevent an accident such as a fire even when a flammable refrigerant leaks.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, an air conditioner according to claim 1 is an air conditioner using a flammable refrigerant , and includes a sensor for detecting a flammable refrigerant gas on an outer surface of an indoor unit ,
The indoor unit is a floor type,
The sensor is provided in a lower part of the indoor unit .
[0006]
In the air conditioner of this aspect, since the sensor for detecting the flammable refrigerant gas is provided on the outer surface of the indoor unit, the flammable refrigerant leaks into the room from the refrigerant pipe (connecting pipe) connected to the indoor unit. When the flammable refrigerant leaked inside the indoor unit flows out of the indoor unit through the gap between the casings, the leaked and gasified refrigerant can be detected by the sensor. Therefore, an alarm can be generated based on the output of the sensor, or the refrigerant circuit can be shut off. As a result, an accident such as a fire can be prevented.
[0007]
A combustible refrigerant such as R32 has a property of being heavier than air. Therefore, when the indoor unit is placed on the floor, a flammable refrigerant leaked into the room from the refrigerant pipe (connection pipe) connected to the indoor unit, or leaked inside the indoor unit to the outside of the indoor unit through the gap in the casing. The flammable refrigerant that has flowed out tends to accumulate on the indoor floor. Here, in the air conditioner according to the first aspect , since the sensor is provided in the lower part of the indoor unit, the combustible refrigerant gas accumulated on the indoor floor can be reliably detected by the sensor. Therefore, accidents such as fire can be reliably prevented.
[0008]
The air conditioner according to claim 2 is an air conditioner using a flammable refrigerant, and includes a sensor for detecting a flammable refrigerant gas on an outer surface of the indoor unit , and the indoor unit is a ceiling fitting type. The sensor is provided in a lower portion facing the ceiling of the indoor unit.
[0009]
As described above, combustible refrigerants such as R32 have the property of being heavier than air. Therefore, when the indoor unit is fitted in the ceiling, the combustible refrigerant leaked into the room from the refrigerant pipe (communication pipe) connected to the indoor unit, or leaked inside the indoor unit to the outside of the indoor unit through the gap in the casing. The flammable refrigerant that has flowed out may accumulate behind the ceiling. Here, in the air conditioner according to the second aspect , the sensor is provided on the outer surface of the casing of the indoor unit and in the lower part facing the back of the ceiling of the indoor unit. The combustible refrigerant gas can be reliably detected by the sensor. Therefore, accidents such as fire can be reliably prevented.
[0010]
The air conditioner according to claim 3 is an air conditioner using a combustible refrigerant, and includes a sensor for detecting a combustible refrigerant gas on an outer surface of the indoor unit, and the sensor is a casing of the indoor unit. It is arrange | positioned at the opening part of a lower part, The combustible refrigerant | coolant gas which leaked to the exterior and the inside of the said indoor unit is detected, It is characterized by the above-mentioned.
[0011]
As described above, combustible refrigerants such as R32 have the property of being heavier than air. Therefore, the combustible refrigerant leaking inside the indoor unit tends to accumulate in the lower part of the indoor unit. Here, in the air conditioner according to claim 3 , the sensor is arranged on an outer surface of the casing of the indoor unit and in an opening of a lower portion of the casing of the indoor unit , and is arranged outside and inside the indoor unit. Since the combustible refrigerant gas leaked into the indoor unit is detected, not only the combustible refrigerant gas leaked to the outside of the indoor unit but also the combustible refrigerant gas leaked inside the indoor unit can be reliably detected by the sensor. Therefore, accidents such as fire can be reliably prevented.
[0012]
Moreover, since the combustible refrigerant gas leaked from one indoor unit and its surroundings can always be detected by the above sensor, a combustible refrigerant gas detection sensor for one indoor unit to prevent an accident such as a fire. Can be done with one, and cost increase can be suppressed. In addition, providing a sensor for detecting refrigerant gas at each location where refrigerant leakage may occur, for example, at each connection location between the refrigerant piping and the heat exchanger in the indoor unit, increases the number of sensors. The cost increases.
[0013]
An air conditioner according to a fourth aspect of the present invention is the air conditioner according to any one of the first to third aspects, further comprising means for issuing an alarm when the sensor detects a flammable refrigerant gas. And
[0014]
In the air conditioner according to the fourth aspect , an alarm is issued when the sensor detects the combustible refrigerant gas. Therefore, the user can know that the flammable refrigerant has leaked, and can take measures such as ventilating the room or calling a service person for repair.
[0015]
The air conditioner according to claim 5 is the air conditioner according to any one of claims 1 to 4 , wherein the operation of the refrigerant circuit of the air conditioner is detected when the sensor detects a flammable refrigerant gas. A control unit that performs control to stop is provided.
[0016]
In the air conditioner of the fifth aspect, when the sensor detects a flammable refrigerant gas, and controls the control unit to stop the operation of the refrigerant circuit of the air conditioner. Accordingly, the refrigerant circuit is blocked by the valve existing on the refrigerant circuit, and the leakage of the combustible refrigerant is suppressed. Note that the combustible refrigerant remaining in the refrigerant pipe flows out to some extent from the problematic leak location, but is no longer pressurized, so the outflow amount is reduced.
[0017]
The air conditioner according to claim 6 is the air conditioner according to any one of claims 1 to 5 , wherein the combustible refrigerant is a mixed refrigerant containing 70 wt% or more of R32 or R32, propane or It is a mixed refrigerant containing propane.
[0018]
A mixed refrigerant containing R32 or R32 in an amount of 70% by weight or more, or a mixed refrigerant containing propane or propane is considered promising as an alternative refrigerant to replace R22. In the air conditioner according to claim 6, when a mixed refrigerant containing 70% by weight or more of R32 or R32, or a mixed refrigerant containing propane or propane, which is regarded as a promising alternative refrigerant for R22, leaks, etc. Can prevent accidents.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the air conditioner of this invention is demonstrated in detail by embodiment of illustration.
[0020]
Drawing 1 shows the place which looked at indoor unit 1 of the air harmony machine of one embodiment from the front, omitting the front panel. FIG. 2 shows the indoor unit 1 as viewed from the right side with the casing 2 partially broken. The indoor unit 1 is a floor-standing type, includes a substantially rectangular parallelepiped casing 2, and is placed on a floor 101 of the room 100.
[0021]
As can be seen from FIG. 2, in the casing 2 of the indoor unit 1, a heat exchanger 3 having a substantially rectangular parallelepiped shape is provided on the front side, and a fan 7 is provided behind the heat exchanger 3. A drain pan 4 for receiving dew generated on the surface of the fins of the heat exchanger 3 is provided immediately below the heat exchanger 3. Further, an outlet 5 for blowing out air is provided immediately below the drain pan 4.
[0022]
As shown in FIG. 1, a pair of connecting pipes 10 for circulating a refrigerant between an outdoor unit (not shown) and the indoor unit 1 pass through holes 31 provided in the lower part of the left side plate 2 a of the casing 2. It is introduced inside the indoor unit 1. The communication pipe 10 is connected to the heat transfer tube 6 of the heat exchanger 3 although not shown. In this air conditioner, a flammable refrigerant composed of R32 is adopted as the refrigerant.
[0023]
In the lower part of the right side plate 2b of the casing 2 of the indoor unit 1, a hole 30 that penetrates the casing 2 in and out is provided as an opening. The hole 30 accommodates a gas sensor 11 for detecting a combustible refrigerant gas such as R32. The gas sensor 11 faces both the outside and the inside of the casing 2 and can detect the combustible refrigerant gas leaked to the outside and the inside of the indoor unit 1.
[0024]
In the casing 2 of the indoor unit 1, a control unit 9 is installed in the upper space adjacent to the right side of the heat exchanger 3 to control the operation of the entire air conditioner.
An alarm device 12 is provided in the space below the control unit 9 for issuing an alarm when an abnormality occurs such as when a flammable refrigerant leaks. This alarm device 12 is provided with a lamp (a light emitting diode) made of LED (light emitting diode) (visible to the occupant through a front panel not shown) and a buzzer to notify the occupant of the occurrence of abnormality through vision and hearing. Contains.
[0025]
The controller 9 is backed up by a storage battery (not shown), and even when the operation of the air conditioner is stopped (when the power switch is off), the gas sensor 11 detects the combustible refrigerant gas and controls the alarm device 12. It can be carried out.
[0026]
During the operation of the air conditioner, the combustible refrigerant is sent from the outdoor unit to the inside of the indoor unit 1 through one of the connecting pipes 10 and flows through the heat transfer pipe 6 of the heat exchanger 3 under the control of the control unit 9. It goes out of the indoor unit 1 and is returned to the outdoor unit through the other side of the connecting pipe 10. At the same time, the fan 7 shown in FIG. 2 is rotated. Thereby, the air in the room 100 is sucked into the casing 2 through the grill of the front panel, and exchanges heat with the combustible refrigerant through the fins of the heat exchanger 3. The air after heat exchange flows downward through the gap between the fan 7 and the back plate 2 c of the casing 2, and is blown out into the room 100 through the blowout port 5.
[0027]
Now, in this air conditioner, the gas sensor 11 for detecting flammable refrigerant gas facing both the inside and outside of the casing 2 is provided below the right side plate 2b of the casing 2 of the indoor unit 1. Therefore, when the combustible refrigerant leaks from the communication pipe 10 to the room 100 or when the combustible refrigerant leaked inside the indoor unit 1 flows out of the indoor unit 1 through the gap of the casing 2, it leaks and gasifies. The refrigerant can be detected by the gas sensor 11.
[0028]
That is, combustible refrigerants such as R32 have a property that they are heavier than air. Therefore, the flammable refrigerant that has leaked from the communication pipe 10 into the room 100 or the flammable refrigerant that has leaked inside the indoor unit 1 and has flowed out of the indoor unit 1 through the gap in the casing 2 tends to accumulate on the floor 101 of the room 100. There is. Here, since the gas sensor 11 is provided in the lower part of the casing 2 and faces the outside of the casing 2, the combustible refrigerant gas accumulated on the floor 101 of the room 100 can be reliably detected by the gas sensor 11. The communication pipe 10 extends to the left from the indoor unit 1, but the flammable refrigerant leaked from the communication pipe 10 quickly diffuses through the floor 101 of the room 100, and the right side plate 2 b of the indoor unit 1. It reaches the place of the gas sensor 11 provided in.
[0029]
Further, the flammable refrigerant leaked inside the indoor unit 1 tends to accumulate in the lower part of the indoor unit 1. For example, in FIG. 1, the combustible refrigerant leaking from the heat transfer tube connection point X in the upper left part of the heat exchanger 3 descends downward, reaches the left end of the drain pan 4, moves to the right on the drain pan 4, and 4 falls from the right end of 4 and reaches the vicinity of the gas sensor 11. Here, since the gas sensor 11 is provided in the lower part of the casing 2 and faces not only the outside of the casing 2 but also the inside, not only the combustible refrigerant gas leaked to the outside of the indoor unit 1 but also The combustible refrigerant gas leaked inside the indoor unit 1 can be reliably detected by the gas sensor 11.
[0030]
FIG. 3 shows the change in the output (sensor detection voltage) Vout of the gas sensor 11 due to the change in the refrigerant concentration C when the flammable refrigerant leaks from the heat transfer tube connection point X in the upper left part of the heat exchanger 3. It shows according to the time passage from. As can be seen, the sensor detection voltage Vout increases as the refrigerant concentration C increases. Incidentally, the reference value Vref shown in FIG. 3, the concentration C of the flammable refrigerant gas corresponds to the value indicated by the sensor detection voltage Vout when it becomes lower flammable limit concentration C _CL.
[0031]
As shown in FIG. 4, the control unit 9 always detects the refrigerant concentration C by the gas sensor 11 (S1), and determines whether or not the sensor detection voltage Vout is equal to or higher than the reference value Vref (S2). If the sensor detection voltage Vout is below the reference value Vref, it is determined that the combustible refrigerant has not leaked, and the refrigerant concentration detection by the gas sensor 11 is continued. On the other hand, if the sensor detection voltage Vout is equal to or higher than the reference value Vref, it is determined that the flammable refrigerant has leaked, and an alarm is immediately issued by the alarm device 12 (S3). Specifically, the LED lamp is blinked and a buzzer is sounded to inform the occupant that the flammable refrigerant has leaked through vision and hearing. Thereby, the user can know that the flammable refrigerant has leaked, and can take measures such as ventilating the room 100 or calling a service person for repair. Moreover, if the control part 9 judges that the combustible refrigerant | coolant leaked, it will perform control which stops the driving | operation of a refrigerant circuit immediately (S4). Thereby, even if this air conditioner is in operation, the refrigerant circuit can be immediately shut off by the valve existing on the refrigerant circuit, and a large amount of combustible refrigerant can be prevented from leaking. As a result, accidents such as fire can be prevented.
[0032]
In this embodiment, the gas sensor 11 for detecting the combustible refrigerant gas facing both the outside and the inside of the casing 2 is provided below the right side plate 2b of the casing 2 of the indoor unit 1. The gas sensor 11 can always detect the combustible refrigerant gas leaked from the indoor unit 1 and its surroundings. Therefore, in order to prevent accidents such as a fire, a single gas sensor for detecting the flammable refrigerant gas can be used for the indoor unit 1, and an increase in cost can be suppressed.
[0033]
FIG. 5 shows a cross section of an indoor unit 50 of an air conditioner according to another embodiment as viewed from the side. This indoor unit 50 is of a ceiling fitting type, includes a substantially rectangular parallelepiped casing 51, and is fitted into the ceiling 201 from the indoor 200 side. In the decorative panel 52 on the lower surface of the casing 51, an air suction grille 54 is formed in the central part, and air outlets 55, 55,... Are formed in the peripheral part, and air is placed between the suction grille 54 and the air outlets 55, 55,. A passage 56 is formed. Inside the casing 51, a turbo fan 58 is built in the center, and the turbo fan 58 has a plurality of blades 59, 59,... Arranged at equal intervals in the circumferential direction between the main plate 58a and the side plate 58b. is doing. A heat exchanger 60 is disposed so as to surround the turbo fan 58 and face the blades 59, 59,.
[0034]
A pair of connecting pipes 80 for circulating the refrigerant between a central unit (not shown) provided at one place in the entire building and the indoor unit 50 pass through the ceiling plate 203 and penetrate the side plate of the casing 51. It is introduced inside the indoor unit 50. Although not shown in the figure, the communication pipe 10 is connected to the heat transfer tube of the heat exchanger 60. In this air conditioner, a flammable refrigerant composed of R32 is adopted as the refrigerant.
[0035]
A gas sensor 71 for detecting a flammable refrigerant gas is attached to a lower portion of the casing 51 of the indoor unit 50 facing the back of the ceiling 202. The gas sensor 71 is exposed on the outer surface of the casing 51, but is embedded in the outer surface of the casing 51 so as not to obstruct the operation of fitting the indoor unit 50 into the hole of the ceiling 201.
[0036]
During the operation of the air conditioner, the combustible refrigerant is sent from the central unit to the inside of the indoor unit 50 through one of the connection pipes 80 and flows through the heat transfer pipe of the heat exchanger 60 under the control of a control unit (not shown). After that, it goes out of the indoor unit 50 and is returned to the central unit through the other of the connecting pipe 80. At the same time, the turbo fan 58 is rotated. As a result, the air in the room 200 is sucked into the casing 51 through the suction grille 54, rises and is blown out in the centrifugal direction by the blades 59, 59,... Of the turbofan 58, and then between the fins of the heat exchanger 60. Exchanges heat with combustible refrigerant. The air after heat exchange flows downward through the air passage 56 and is blown out into the room 200 through the air outlet 55.
[0037]
When the flammable refrigerant leaks from the connecting pipe 80 to the ceiling place 203, or when the flammable refrigerant leaked inside the indoor unit 50 flows into the ceiling place 203 through the gap of the casing 51, the flammable refrigerant such as R32 is air. Therefore, the leaked combustible refrigerant accumulates in the ceiling 202. Here, since the gas sensor 71 is provided in the lower part facing the ceiling back 202 of the indoor unit 50 so as to be exposed on the outer surface of the casing 51, the leaked combustible refrigerant can be reliably detected by the gas sensor 71. Therefore, an alarm can be generated based on the output of the sensor or the refrigerant circuit can be shut off by the control of the control unit, and as a result, an accident such as a fire can be prevented.
[0038]
In each embodiment, the combustible refrigerant is made of R32. However, the present invention is not limited to this. The present invention can be widely applied to an air conditioner using a combustible refrigerant such as a mixed refrigerant containing R32 by 70 weight percent or more, or a mixed refrigerant containing propane or propane.
[0039]
【The invention's effect】
As is clear from the above, in the air conditioner according to claims 1 to 6, even when the combustible refrigerant leaks, the leaked combustible refrigerant can be detected by the sensor. Therefore, accidents such as fire can be prevented.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an indoor unit of an air conditioner according to an embodiment of the present invention as viewed from the front without a front panel.
FIG. 2 is a diagram showing the indoor unit as viewed from the right side with a casing partially broken.
FIG. 3 is a diagram showing a change in sensor detection voltage Vout accompanying a change in refrigerant concentration C as time elapses from the start of leakage.
FIG. 4 is a diagram illustrating a control flow by a control unit of the air conditioner.
FIG. 5 is a sectional view showing the indoor unit of the air conditioner according to the embodiment of the present invention as viewed from the side.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Indoor unit 2,51 Casing 9 Control part 10,80 Connection piping 11,71 Gas sensor

Claims (6)

In an air conditioner using a flammable refrigerant,
A sensor (11, 71) for detecting a combustible refrigerant gas is provided on the outer surface of the indoor unit (1, 50) .
The indoor unit (1) is a floor type,
The air conditioner characterized in that the sensor (11) is provided in a lower part of the indoor unit (1) . In an air conditioner using a flammable refrigerant ,
A sensor (11, 71) for detecting a combustible refrigerant gas is provided on the outer surface of the indoor unit (1, 50).
The indoor unit (50) is a ceiling fitting type,
The air conditioner according to claim 1, wherein the sensor (71) is provided in a lower part facing the back of the ceiling ( 202 ) of the indoor unit (50). In an air conditioner using a flammable refrigerant ,
A sensor (11, 71) for detecting a combustible refrigerant gas is provided on the outer surface of the indoor unit (1, 50).
The sensor (11) is disposed in an opening (30) at a lower portion of the casing of the indoor unit (1), and detects a combustible refrigerant gas leaked outside and inside the indoor unit (1). Air conditioner to do. The air conditioner according to any one of claims 1 to 3 ,
An air conditioner comprising means (12, 9) for issuing an alarm when the sensor (11) detects a flammable refrigerant gas. The air conditioner according to any one of claims 1 to 4 ,
When the said sensor (11) detects combustible refrigerant | coolant gas, the said control part (9) performs control which stops the driving | operation of the refrigerant circuit of this air conditioner, The air conditioner characterized by the above-mentioned. The air conditioner according to any one of claims 1 to 5 ,
The flammable refrigerant is an air conditioner characterized in that it is R32 or a mixed refrigerant containing R32 or R32 or more by weight, or a mixed refrigerant containing propane or propane.

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