JP6519360B2 - Indoor unit of air conditioner - Google Patents

Description

  The present invention relates to an indoor unit of an air conditioner.

  BACKGROUND ART In recent years, adoption of R32 refrigerant with a low global warming potential has progressed in air conditioners that perform indoor air conditioning by a vapor compression refrigeration cycle. However, R32 refrigerant has slight flammability (slight flammability), and if the refrigerant whose specific gravity is larger than air leaks, it may stay near the floor surface and reach the flammable concentration. For this reason, in order to determine the presence or absence of the leak from a refrigerant circuit, a refrigerant sensor is arranged in an indoor unit, and when this refrigerant sensor detects the leak of a refrigerant, the on-off valve arranged in the refrigerant circuit is opened and the said It has been proposed that the leaked refrigerant be collected in a container connected to the on-off valve (see Patent Document 1), or the indoor fan provided in the indoor unit be driven to diffuse the leaked refrigerant (Patent Document 2). There is.

JP 2000-171130 A Japanese Patent Application Laid-Open No. 11-37619

  However, if the refrigerant leak location is separated from the location where the refrigerant sensor is located, or a flow path (for example, an air inlet, etc.) that allows the refrigerant to leak outside the machine near the coolant leakage location. There is a possibility that the leaked refrigerant can not be detected when the If the amount of leaked refrigerant is small, there is almost no possibility of reaching the flammable concentration even if leakage continues, but for example, a refrigerant circuit like an air conditioner in which a plurality of indoor units are connected to one outdoor unit In the case where a large amount of refrigerant is sealed therein, if a refrigerant leak occurs in one indoor unit, a large amount of the refrigerant continues to leak as it is, which may reach a flammable concentration.

  On the other hand, although it is conceivable to place a large number of refrigerant sensors at different locations in the aircraft, this is a significant cost increase and is not a practical solution.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide an indoor unit of an air conditioner capable of reliably detecting a refrigerant leak with a minimum refrigerant sensor.

(1) The indoor unit of the air conditioner according to the present invention (hereinafter, also simply referred to as “indoor unit”) is a unit that transmits air passing through a heat exchanger using a slightly flammable or flammable refrigerant having a specific gravity larger than that of air. An indoor unit of an air conditioner in which a fan is blown out from an outlet and a refrigerant sensor is disposed in the machine,
And a controller for controlling the opening and closing of the outlet and the operation of the indoor fan.
The control unit performs the leak detection operation of circulating the air in the machine by driving the indoor fan at a rotation speed equal to or less than the minimum rotation speed in the normal operation in a state where the blowout port is closed.

  In the indoor unit according to the present invention, the control unit circulates the air inside the unit by driving the indoor fan at a rotation speed equal to or lower than the minimum rotation speed in normal operation with the blowout port of the indoor unit closed. Leak detection operation). Thereby, even if the leaked portion of the refrigerant and the disposition portion of the refrigerant sensor are separated, the leaked refrigerant can be carried on the air flow and guided to the refrigerant sensor, and the leakage of the refrigerant can be detected. . As a result, even if the number of refrigerant sensors is minimal, usually one, refrigerant leakage can be detected. When the number of rotations of the indoor fan becomes larger than the minimum number of rotations, the refrigerant may be diffused and may not be detected by the refrigerant sensor.

(2) In the indoor unit of the above (1), the control unit performs the leak detection operation when the difference between the temperature of the intake air into the device and the operation set temperature of the indoor unit becomes equal to or less than a predetermined value. It can be done. In this case, since the indoor temperature is close to the set temperature, the comfort of the living space is not impaired even if the operation of the indoor fan is switched from the normal operation to the leakage detection operation.

(3) In the indoor unit of (1), the control unit may perform the leakage detection operation when starting the operation of the indoor unit. In this case, it is possible to additionally perform the leakage detection for detecting the leakage of the refrigerant during the start-up operation with a small number of rotations immediately after the start of the operation. At this time, it is necessary to close the air outlet while the leak detection operation is being performed.

(4) In the indoor unit of the above (1), the control unit may perform the leak detection operation every predetermined time after the start of the operation of the indoor unit. In this case, it can be regularly checked whether the refrigerant is leaking.

(5) In the indoor unit of the above (1) to (4), it is preferable that the control unit repeats a cycle consisting of operation and stop of the indoor fan at the rotational speed a plurality of times in the leakage detection operation. In this case, air can be circulated to every corner of the machine by stopping the operation once, rather than operating the indoor fan continuously.

(6) In the indoor unit of the above (1) to (5), the refrigerant sensor can be disposed below a connection portion to which a refrigerant pipe from the outside is connected to the heat exchanger. In this case, by disposing the refrigerant sensor below the portion where there is a high possibility of refrigerant leakage, it is possible to more reliably detect the refrigerant leak.

(7) In the indoor unit of the above (1) to (6), the refrigerant sensor can be disposed in the vicinity of a drain discharge portion in a drain pan disposed below the heat exchanger. In this case, the refrigerant that has leaked from the heat exchanger moves toward the drain discharge portion in the drain pan disposed below the heat exchanger, so that the leakage of the refrigerant can be detected more reliably. .
(8) In the indoor unit of the above (1) to (5), a box enclosing the pipe connection portion outside the casing of the indoor unit and a flow path for leading the leaked refrigerant in the box to the inside of the casing it can. In this case, since a box surrounding the pipe connection portion outside the casing is provided and a flow path for leading the leaked refrigerant in the box to the inside of the casing is provided, the leakage detection operation of the refrigerant described above causes leakage of refrigerant. Even if the refrigerant sensor and the refrigerant sensor are separated, the leaked refrigerant introduced into the casing can be carried on the air flow and guided to the refrigerant sensor, and the refrigerant leakage can be detected.

  According to the indoor unit of the present invention, it is possible to reliably detect a refrigerant leak with a minimum refrigerant sensor.

It is a perspective view of one embodiment of the indoor unit of the present invention. It is cross-sectional explanatory drawing of the indoor unit shown by FIG. It is plane | planar explanatory drawing of the indoor unit shown by FIG. It is a figure explaining movement of a flap. It is plane | planar explanatory drawing of other embodiment of the indoor unit of this invention. FIG. 6 is a partially enlarged plan view of the indoor unit shown in FIG. 5; It is cross-sectional explanatory drawing of the indoor unit shown by FIG.

  Hereinafter, embodiments of the indoor unit of the present invention will be described in detail with reference to the attached drawings. FIG. 1 is a perspective view of an indoor unit 1 according to an embodiment of the present invention, FIG. 2 is an explanatory sectional view of the indoor unit 1 shown in FIG. 1, and FIG. 3 is an indoor view shown in FIG. FIG. 2 is an explanatory plan view of the machine 1;

  The indoor unit 1 is a ceiling-embedded indoor unit, and includes a casing 2 that houses various elements such as an indoor fan and a heat exchanger described later, and a decorative panel 3. The casing 2 is a box-like body whose lower end face is opened, and is disposed in an opening formed in the ceiling C as shown in FIG. The decorative panel 3 is formed of a rectangular plate, and a suction port 4 for sucking air in the air-conditioned room is formed at the center. Further, an elongated rectangular air outlet 5 for blowing conditioned air into the air-conditioned room is formed around the inlet 4 along each side of the decorative panel 3.

  Each air outlet 5 is provided with a flap 5 a for adjusting the wind direction of the conditioned air blown out from the air outlet 5 into the air-conditioned room. The flap 5 a is pivotable about an axis along the longitudinal direction of the outlet 5. The rotation of the flap 5a can be performed by a motor (not shown). The flap 5a has a size and a shape that can substantially close the outlet 5, as shown in the flap 5a on the left side of FIG.

  From the indoor side, a suction grill 6 and a filter 7 for removing dust in indoor air sucked from the suction port 4 are disposed in this order from the indoor side to the suction port 4 of the decorative panel 3.

  Inside the casing 2, the air in the air-conditioned room is sucked from the suction port 4 of the decorative panel 3, and after heat exchange, the indoor fan 8 blows out the conditioned air from the blow-out port 5 of the decorative panel 3 into the air-conditioned room And a heat exchanger 9 disposed so as to surround the indoor fan 8. The indoor fan 8 has a motor 10 and an impeller 11. Further, in the casing 2, there is disposed a control unit P which controls the opening and closing of the air outlet 5 and the operation of the indoor fan 8 by the rotation of the flap 5a.

  The heat exchanger 9 is a cross fin tube type heat exchanger formed by being bent so as to surround the indoor fan 8 and is connected to one end 9a (see FIG. 3) from an outdoor unit (not shown). A refrigerant pipe is connected. Below the heat exchanger 9, a drain pan 12 is disposed for receiving a drain generated by condensation of water in the air which is heat-exchanged by the heat exchanger 9.

  A groove 13 is formed in the drain pan 12, and the lower end of the heat exchanger 9 is disposed in the groove 13. The bottom surface of the groove portion 13 is an inclined surface so that one portion is the lowest portion, and it has fallen from the heat exchanger 9 and has flowed on the inclined bottom surface in the groove portion having the lowest bottom surface 13a. A drain pump 14 for draining is provided. In the drain pan 12, a suction hole 15 corresponding to the suction port 4 of the decorative panel 3 and a blowout hole 16 corresponding to the blowout port 5 of the decorative panel 3 are formed. A bell mouth 17 is attached to the inner edge of the suction hole 15 for guiding the air sucked from the suction port 4 of the decorative panel 3 to the impeller 11 of the indoor fan 8.

  The indoor unit 1 in the present embodiment uses, as a refrigerant, R32 refrigerant which is a slightly flammable or flammable refrigerant. Since this R32 refrigerant has a specific gravity larger than that of air, if it leaks and stays on a floor surface or the like, there is a possibility of reaching the flammable concentration. For this reason, in the present embodiment, in the vicinity of the end portion 9a of the heat exchanger 9 provided with the connection portion where the heat exchanger 9 and the refrigerant pipe from the outside are connected with a high possibility of refrigerant leakage. A refrigerant sensor 18 is provided. More specifically, the refrigerant sensor 18 is disposed on the bottom surface 13b of the groove 13 of the drain pan 12 in the vicinity of the end 9a.

  In the present embodiment, in addition to the normal operation of the indoor unit 1, the control unit P performs a leakage detection operation to detect the refrigerant that has leaked from the heat exchanger 9 or the like. In this leakage detection operation, with the flap 5a being driven to close the air outlet 5, the indoor fan 8 is driven at a rotational speed less than the minimum rotational speed in normal operation to circulate air in the machine. Thereby, even if the leakage portion of the refrigerant and the vicinity of the end 9a of the heat exchanger 9 where the refrigerant sensor 18 is disposed are separated, the refrigerant sensor carrying the leakage refrigerant in the air flow It can lead up to 18 and can detect refrigerant leakage.

  The “rotation speed lower than the minimum rotation speed” is not particularly limited in the present invention as long as a wind speed or an air volume capable of circulating air in the machine can be obtained. The minimum number of revolutions of the indoor fan 8 varies depending on the model etc., but is, for example, 300 rpm.

  Further, in the present specification, “close” of the outlet is not limited to the case where the flow of air from the outlet to the air-conditioning room is substantially blocked (see the outlet on the left side of FIG. 2). Is a concept that also includes states that are suppressed. For example, as shown in (a) of FIG. 4, the flap 25 a provided at the outlet 25 is not only in the normal closed state where the convex curved surface of the flap 25 a faces the outer side but also in FIG. Since the flow of air into the air-conditioned room is suppressed even when the flap 25a is inverted so that the convex curved surface is directed to the inside as shown in FIG. Shall be included in the closing of the In addition, in FIG. 4, the code | symbol C has shown the ceiling and the code | symbol "3" has shown the decorative panel of the indoor unit.

  Various modes can be considered as the timing at which the leak detection operation is carried out. For example, when the difference between the temperature of intake air into the machine and the operation set temperature of the indoor unit 1 becomes equal to or less than a predetermined value, The leak detection operation can be performed when the condition is reached. In this case, since the indoor temperature is close to the set temperature, even if the operation of the indoor fan 8 is switched from the normal operation to the leakage detection operation and the air blowing to the air conditioning chamber is temporarily stopped, the residence There is no loss of space comfort.

  Also, the leak detection operation can be performed when the operation of the indoor unit 1 is started. In this case, it is possible to additionally perform the leak detection for detecting the leakage of the refrigerant during the start-up operation where the number of rotations is small (the number of rotations less than the minimum rotation speed) immediately after the start of operation. During the leak detection operation, the air outlet 5 needs to be closed by the flap 5a.

  In addition, after the start of the operation of the indoor unit 1, it is also possible to perform the leak detection operation every predetermined time, for example, every hour. In this case, it can be regularly checked whether the refrigerant is leaking.

  In the leakage detection operation, the indoor fan 8 may be operated continuously at the rotation speed, but it is preferable to repeat a cycle consisting of operation and stop at the predetermined rotation speed a plurality of times. Air can be circulated to every corner of the machine by stopping the operation once, rather than operating the indoor fan continuously.

[Other Modifications]
The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims.
For example, although the refrigerant sensor is disposed near the end 9 a of the heat exchanger 9 in the above-described embodiment, the drain in the drain pan 12 disposed below the heat exchanger 9, for example, other than this It can arrange | position in the vicinity of a discharge part (location where a drain pump is arrange | positioned). In this case, since the refrigerant leaking from the heat exchanger 9 moves toward the drain discharge portion in the drain pan 12 disposed below the heat exchanger 9, it is possible to reliably detect the leakage of the refrigerant. Can.

  In the embodiment described above, although the ceiling-embedded indoor unit is illustrated, as long as the blowout port can be closed, another type of indoor unit, for example, a ceiling-hanging indoor unit, a wall-hanging indoor unit The present invention can also be applied to machines and the like.

  Further, although the number of refrigerant sensors is “1” in the above-described embodiment, the number may be “2” depending on the size of the indoor unit. In this case, although the cost reduction effect is reduced, the refrigerant leakage can be detected more reliably. In the present specification, “minimum” means that the number of refrigerant sensors is not necessarily limited to “1”.

  Moreover, in the embodiment described above, the control unit is disposed in the casing of the indoor unit, but such a control unit can be incorporated in, for example, a remote controller outside the indoor unit.

  Further, in the above-described embodiment, the refrigerant leaking inside the casing of the indoor unit is detected, but the refrigerant leaking outside the casing can also be detected. For example, as shown in FIGS. 5 to 7, when the refrigerant piping from the outdoor unit and the refrigerant piping from the inside of the apparatus are connected outside the casing 2, the refrigerant leakage from the piping connection portion 30 is caused by the refrigerant in the casing 2. It is also possible to detect by the sensor 18. In the indoor units shown in FIGS. 5 to 7, the same or similar components as or to those of the indoor units shown in FIGS. 1 to 3 are denoted by the same reference numerals, and the description thereof will be omitted for simplicity.

Concretely, the pipe connection part 30 which exists outside the casing 2 is airtightly enclosed by the box 31, and the flow path 32 from the inside of the said box 31 to the groove part 13 of the drain pan 12 is provided. In the embodiment shown in FIGS. 5 to 7, the flow path 32 is a flow path leading to the refrigerant sensor 18 disposed at the deepest portion D (see FIG. 5) of the lempan (see arrow A in FIG. 6). As shown by a two-dot chain line in FIG. 6, a flow path 32a may be provided which leads to the refrigerant sensor 18a disposed in the vicinity of the outlet 16.
By adopting the above configuration, the refrigerant leaking from the pipe connection portion 30 fills the inside of the box 30 and then flows to the deepest portion D of the drain pan through the flow path 32. Then, even if the outlet of the flow path 32 is separated from the installation location of the refrigerant sensor 18 by performing the leakage detection operation described above, the leakage refrigerant can be introduced onto the air flow and guided to the refrigerant sensor 18 It is possible to detect the leakage of the refrigerant.

1: indoor unit 2: casing 3: cosmetic panel 4: suction port 5: outlet 5 a: flap 6: suction grille 7: filter 8: indoor fan 9: heat exchanger 9 a: end 10: motor 11: impeller 12 A: drain pan 13: groove 13a: bottom 13b: bottom 14: drain pump 15: suction hole 16: outlet hole 17: bell mouth 18: refrigerant sensor 18a: refrigerant sensor 25: outlet 25a: flap 30: piping connection 31: box Body 32: Flow path C: Ceiling D: deepest part P: Control part

Claims (8)

Air passing through the heat exchanger (9) using a slightly flammable or flammable refrigerant having a specific gravity larger than air is blown out from the blowout port (5) by the indoor fan (8), and a refrigerant sensor (18) in the machine Is an indoor unit (1) of an air conditioner in which
It further comprises a control unit (P) for controlling the opening and closing of the air outlet (5) and the operation of the indoor fan (8),
The control unit (P) is a state where the air outlet (5) is closed, and the indoor fan (8) is driven at a rotation speed equal to or lower than a minimum rotation speed during normal operation to circulate air in the machine. The indoor unit (1) of the air conditioner that operates.   The said control part (P) performs the said leak detection driving | operation, when the difference of the temperature of the suction | inhalation air to the inside of a machine, and the operation setting temperature of an indoor unit (1) becomes below in predetermined value. Indoor unit (1).   The indoor unit (1) according to claim 1, wherein the control unit (P) performs the leak detection operation when starting the operation of the indoor unit (1).   The indoor unit (1) according to claim 1, wherein the control unit (P) performs the leak detection operation every predetermined time after the start of the operation of the indoor unit (1).   The control unit (P) according to any one of claims 1 to 4, wherein in the leakage detection operation, a cycle consisting of operation and stop of the indoor fan (8) at the rotation speed is repeated a plurality of times. Indoor unit (1).   The refrigerant sensor (18) according to any one of claims 1 to 5, wherein the refrigerant sensor (18) is disposed below a connection portion to which a refrigerant pipe from outside the machine is connected to the heat exchanger (9). The indoor unit (1) as described.   The refrigerant sensor (18) according to any one of claims 1 to 5, wherein the refrigerant sensor (18) is disposed in the vicinity of a drain discharge portion of a drain pan (12) disposed below the heat exchanger (9). The indoor unit (1) as described in a term. A box (31) surrounding a pipe connection portion (30) outside the casing (2) of the indoor unit (1), and a flow path (32) for leading the leaked refrigerant in the box (31) into the casing (2) The indoor unit (1) according to any one of claims 1 to 5, further comprising

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