JP2015094512A - Indoor unit for floor-installed air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an indoor unit for a floor-installed air conditioner capable of reducing risk accompanying leakage of a combustible refrigerant by facilitating dispersion of the refrigerant by raising a leakage outlet to the outside high from the floor surface when the combustible refrigerant leakage from the inside of a body casing occurs.SOLUTION: An indoor unit for a floor-installed air conditioner includes: an indoor fan 18 arranged inside body casings (31, 32) and blowing out air sucked via an indoor heat exchanger 15; a refrigerant sensor arranged inside the body casings (31, 32) and detecting leakage of a combustible refrigerant; and an indoor control device for controlling a shutter 50 (opening/closing member) for opening/closing a lower side outlet 32b (lower side opening). When the leakage of the combustible refrigerant is detected by the refrigerant sensor, the indoor control device controls the shutter 50 and brings the lower side outlet 32b into a closed state.

Description

  The present invention relates to an indoor unit of a floor type air conditioner, and more particularly to an indoor unit of a floor type air conditioner using a combustible refrigerant.

  Conventionally, as an indoor unit of a floor-mounted air conditioner, an indoor heat exchanger is arranged in a floor-mounted main body casing, and air sucked by a blower fan through the indoor heat exchanger is used as an upper air outlet and a lower air outlet. There is one that blows out from the outlet (see, for example, Japanese Patent Application Laid-Open No. 2011-202886 (Patent Document 1)).

JP 2011-202886 A

  In the above-described indoor unit of the floor type air conditioner, when refrigerant is leaked from a connection portion between the indoor heat exchanger in the main body casing and the refrigerant pipe in the operation stop state, the lower suction, which is the lowest opening in the main body casing Since the refrigerant gas flows out to the floor surface through the opening, there is a possibility that the concentration of the refrigerant gas staying in the vicinity of the indoor floor becomes high. When the gas concentration of the combustible refrigerant increases to some extent, the risk of ignition and the like increases.

  Accordingly, an object of the present invention is to reduce the risk associated with the leakage of the flammable refrigerant by promoting the diffusion of the refrigerant by raising the leakage outlet to the outside from the floor surface when the flammable refrigerant leaks from the inside of the main body casing. An object of the present invention is to provide an indoor unit for a floor-mounted air conditioner.

In order to solve the above problems, an indoor unit of a floor-mounted air conditioner of the present invention is
A body casing;
An indoor heat exchanger disposed in the main body casing and through which a flammable refrigerant flows;
A blower fan that is arranged in the main body casing and blows out air sucked through the indoor heat exchanger;
Provided in the main body casing, an upper opening that is a blowout port or a suction port of the blower fan, and
A lower opening provided in the main body casing and serving as a blow-out port or a suction port of the blower fan;
A refrigerant sensor disposed in the main body casing for detecting leakage of the combustible refrigerant;
An opening and closing member for opening and closing the lower opening;
A control device for controlling the blower fan and the opening and closing member;
The control device controls the opening / closing member to close the lower opening when the refrigerant sensor detects leakage of the combustible refrigerant.

  Here, the flammable refrigerant is a substance containing a slightly flammable refrigerant such as R32. Further, the floor-mounted air conditioner is not limited to the one directly placed on the floor surface, and may be one that is placed so that the bottom is positioned one step higher than the floor surface or embedded in the wall. .

  According to the above configuration, for example, when the flammable refrigerant leaks from the connection portion between the indoor heat exchanger in the main body casing and the refrigerant pipe in the operation stop state, the refrigerant sensor disposed in the main body casing causes the flammable refrigerant to flow. When the leakage is detected, the control device controls the opening / closing member to close the lower opening, which is the air outlet or the air inlet of the blower fan. By doing so, the combustible refrigerant gas is prevented from flowing out to the floor of the room through the lower suction port located at the lowest position in the main body casing, and the opening portion (upper opening at the upper position) in the main body casing is prevented. Since the flammable refrigerant gas heavier than air flows out and falls from (including), the diffusion of the flammable refrigerant gas is promoted before dropping to the floor surface. Thereby, it is possible to prevent the leaked combustible refrigerant gas from staying in the vicinity of the indoor floor and increasing the gas concentration.

  As described above, when the flammable refrigerant leaks from the inside of the main casing, the leakage outlet to the outside is raised from the floor surface to promote the diffusion of the refrigerant, thereby reducing the risk associated with the leakage of the flammable refrigerant.

Moreover, in the indoor unit of the floor-mounted air conditioner of one embodiment,
An upper opening adjusting member for adjusting the opening area of the upper opening;
When the leakage of the flammable refrigerant is detected by the refrigerant sensor, the control device controls the upper opening adjustment member to increase the opening area of the upper opening than before detecting the leakage of the flammable refrigerant. .

  According to the embodiment, when the leakage of the flammable refrigerant is detected by the refrigerant sensor, the upper opening adjustment member is controlled by the control device so that the opening area of the upper opening is larger than that before the leakage of the flammable refrigerant is detected. By spreading, the combustible refrigerant gas easily flows out from the upper opening at a high position of the main casing, so that the combustible refrigerant gas flowing out from the upper opening can be effectively diffused.

Moreover, in the indoor unit of the floor-mounted air conditioner of one embodiment,
The lower opening is a blowout port for blowing out air from the blower fan,
The opening / closing member also serves as a blower outlet damper for opening / closing the lower opening which is the blower outlet.

  According to the above embodiment, the opening / closing member serves also as a blowout outlet damper for opening and closing the lower opening that is the blowout opening during operation, and when the leakage of the flammable refrigerant is detected by the refrigerant sensor, The lower opening which is a blower outlet can be made into a closed state with the opening-and-closing member which serves as a damper.

Moreover, in the indoor unit of the floor-mounted air conditioner of one embodiment,
As the combustible refrigerant, a single refrigerant made of R32 or a mixed refrigerant containing R32 as a main component was used.

  According to the embodiment, by using a single refrigerant composed of R32 or a mixed refrigerant mainly composed of R32 as a combustible refrigerant, R32 has a low ozone depletion coefficient and a global warming potential GWP (Global Warming Potential). Therefore, the influence of global warming can be suppressed, and the coefficient of performance (COP) can be improved to reduce energy consumption.

  As is clear from the above, according to the present invention, when the flammable refrigerant leaks from the inside of the main body casing, the leakage outlet to the outside is increased from the floor surface to promote the diffusion of the flammable refrigerant. It is possible to realize an indoor unit of a floor-standing air conditioner that can reduce the risk associated with the.

FIG. 1 is a circuit diagram of a refrigerant circuit of an indoor unit and an outdoor unit of a floor type air conditioner according to an embodiment of the present invention. FIG. 2 is a perspective view of the indoor unit of the floor type air conditioner. FIG. 3 is a front view of the floor type air conditioner with the suction panel and the front grill removed from the indoor unit. 4 is a cross-sectional view taken along line IV-IV in FIG. FIG. 5 is a sectional view taken along line VV in FIG. FIG. 6 is a control block diagram of the indoor unit of the floor type air conditioner. FIG. 7 is a flowchart for explaining the operation of the indoor control device for the indoor unit.

  Hereinafter, an indoor unit of a floor-mounted air conditioner according to the present invention will be described in detail with reference to embodiments shown in the drawings.

  FIG. 1 shows an indoor unit 2 of a floor-mounted air conditioner according to an embodiment of the present invention and a refrigerant circuit of the outdoor unit 1 connected to the indoor unit 2 via connecting pipes L1 and L2. As shown in FIG. 1, the air conditioner has a compressor 11, a four-way switching valve 12 connected to one end of the discharge side of the compressor 11, and one end connected to the other end of the four-way switching valve 12. And the other end of the outdoor heat exchanger 13 is connected to the other end of the outdoor heat exchanger 13, and the other end of the electric expansion valve 14 is connected to the other end via the closing valve 21 and the communication pipe L1. Is connected to the other end of the indoor heat exchanger 15 through the connecting pipe L2, the closing valve 22, and the four-way switching valve 12, and the other end is sucked into the compressor 11. And an accumulator 16 connected to the side. The compressor 11, the four-way switching valve 12, the outdoor heat exchanger 13, the electric expansion valve 14, the indoor heat exchanger 15 and the accumulator 16 constitute a refrigerant circuit. In this refrigerant circuit, a single refrigerant of R32 or a mixed refrigerant containing R32 as a main component is used.

  The compressor 11, the four-way switching valve 12, the outdoor heat exchanger 13, the electric expansion valve 14, the accumulator 16, the outdoor fan 17 and the humidifying unit 42 constitute the outdoor unit 1, and the indoor heat exchanger 15 and the indoor fan. The indoor unit 2 is configured by the duct 18 and the duct unit 40.

  In addition, the air conditioner includes a duct portion 40 for supplying humidified air from the outside to the indoor unit 2, and also connects one end of the humidifying hose 41 to the humidifying unit 42 of the outdoor unit 1, The other end of the hose 41 is connected to the hose connection part 40 b of the duct part 40 of the indoor unit 2.

  The outdoor unit 1 includes an outdoor control device 100 that controls the compressor 11 and the outdoor fan 17. The indoor unit 2 includes an indoor control device 200 as an example of a control device that controls the indoor fan 18 and the like based on a remote controller, an indoor temperature sensor (not shown), and the like.

  In the air conditioner configured as described above, when the four-way switching valve 12 is switched to the solid line switching position and the compressor 11 is started during heating operation, the high-pressure refrigerant discharged from the compressor 11 passes through the four-way switching valve 12. And enters the indoor heat exchanger 15. The refrigerant condensed in the indoor heat exchanger 15 enters the outdoor heat exchanger 13 after being depressurized by the electric expansion valve 14. The refrigerant evaporated in the outdoor heat exchanger 13 returns to the suction side of the compressor 11 through the four-way switching valve 12 and the accumulator 16. In this way, the refrigerant circulates through the refrigerant circuit constituted by the compressor 11, the indoor heat exchanger 15, the electric expansion valve 14, the outdoor heat exchanger 13 and the accumulator 16, thereby executing a refrigeration cycle. Then, the indoor fan 18 heats the room by circulating the room air through the indoor heat exchanger 15.

  On the other hand, during the cooling operation, the four-way switching valve 12 is switched to the dotted line switching position, and the refrigerant in the order of the compressor 11, the outdoor heat exchanger 13, the electric expansion valve 14, the indoor heat exchanger 15, and the accumulator 16. Execute a refrigeration cycle that circulates.

  When the room is dried during heating operation or the like, the humidified air from the humidifying unit 42 is supplied to the room through the humidifying hose 41 and the duct portion 40. The humidifying unit 42 adsorbs moisture from the outdoor air using an adsorbent such as zeolite, humidifies the outdoor air with the moisture adsorbed on the adsorbent, and then supplies the humidified outdoor air to the indoor unit 2. It is. Note that the configuration of the humidifying unit is not limited to this, and a humidifying unit that supplies humidified air to the indoor unit using water replenished by water supply means such as tap water may be used.

  FIG. 2 is a perspective view of the indoor unit of the floor type air conditioner.

  As shown in FIG. 2, the indoor unit 2 of the floor-type air conditioner is attached to a substantially rectangular bottom frame 31 whose rear side is attached to the wall surface of the room, and to the front side of the bottom frame 31, and to the front side. A front grill 32 having a rectangular opening (not shown) and a suction panel 33 attached so as to cover the opening of the front grill 32 are provided. The bottom frame 31 and the front grill 32 constitute a main body casing.

  An upper air outlet 32a as an example of an upper opening is provided in the upper part of the front grill 32, and a lower air outlet 32b as an example of a lower opening is provided in the lower part of the front grill 32. A flap 34 as an example of an upper opening adjustment member is provided at the upper outlet 32a of the front grill 32. The flap 34 rotates during the cooling operation and the heating operation, blows cool air and warm air forward and obliquely upward from the upper air outlet 32a, and covers the upper air outlet 32a when the operation is stopped.

  Further, an upper suction port 33a is provided on the upper side of the suction panel 33, a lower suction port 33b is provided on the lower side of the suction panel 33, and a side suction port 33c (right side in FIG. Only shown).

  FIG. 3 shows a front view of the floor type air conditioner with the suction panel 33 and the front grill 32 of the indoor unit 2 removed. 3, the same components as those of the indoor unit 2 shown in FIG.

  As shown in FIG. 3, a substantially planar indoor heat exchanger 15 is disposed on the front side of the bottom frame 31, and an indoor fan 18 as an example of a blower fan is disposed on the back side thereof. The indoor fan 18 is a turbo fan that sucks air from the front side and blows it outward in the radial direction. A duct portion 40 having an indoor side opening 40a is disposed near and below the left side surface of the bottom frame 31.

  Further, near the right side surface of the bottom frame 31, there is provided a pipe connecting portion (not shown) to which connecting pipes L1 and L2 (shown in FIG. 1) are connected. The connecting pipes L1 and L2 enter the vicinity of the left side of the bottom frame 31 and the lower side thereof together with the humidifying hose 41 (shown in FIG. 1) from the back side, and the lower side of the bottom frame 31 faces from the left to the right in FIG. To be connected to the pipe connection.

  Further, a refrigerant sensor 60 for detecting leakage of the R32 refrigerant is disposed on the bottom frame 31 side and in the vicinity of the right side surface in the main body casing.

  4 shows a cross-sectional view taken along line IV-IV in FIG. 4, the same reference numerals are assigned to the same components as those of the indoor unit 2 shown in FIG.

  As shown in FIG. 4, the fan motor 26 is fixed to the approximate center of the bottom frame 31. The indoor fan 18 to which the shaft of the fan motor 26 is connected is disposed on the bottom frame 31 so that the shaft is in the front-rear direction. The indoor fan 18 is a turbo fan that blows air sucked from the front side outward in the radial direction with respect to the shaft. A bell mouth 27 is provided on the bottom frame 31 on the front side of the indoor fan 18. The indoor heat exchanger 15 is arranged on the front side of the bell mouth 27, the front grill 32 is attached to the front side of the indoor heat exchanger 15, and the suction panel 33 is attached to the front side of the front grill 32. . A filter (not shown) is attached to the opening of the front grill 32. A drain pan 28 is disposed below the bell mouth 27 and below the indoor heat exchanger 15.

  Further, a shutter 50 as an example of an opening / closing member that opens and closes the lower air outlet 32b is disposed in the blowout passage below the front grill 32. The shutter 50 is rotated about a shaft 50a provided on the bottom frame 31 side by a shutter driving unit 51 (shown in FIG. 6), and is used for a blowout port that makes the lower blowing passage fully open or fully closed. It is a damper.

  In the indoor unit 2 of the floor type air conditioner, the two-way blow control for blowing warm air from both the upper blower outlet 32a and the lower blower outlet 32b and the lower blower outlet 32b are closed by the shutter 50 during the heating operation. There is a one-sided blow control that blows warm air only from one of the upper outlets 32a. Further, during cooling operation, cool air is blown out only from one of the upper air outlets 32a.

  5 shows a cross-sectional view taken along line V-V in FIG. 3. In FIG. 5, the same reference numerals are assigned to the same components as the indoor unit 2 shown in FIG. FIG. 5 shows a state where the suction panel 33 and the front grill 32 are removed.

  As shown in FIG. 5, the refrigerant sensor 60 is disposed on the bottom frame 31 side and the lower side in the main body casing (configured by the bottom frame 31 and the front grill 32). The refrigerant sensor 60 is a sensor that heats a semiconductor with a heater.

  FIG. 6 shows a control block diagram of the indoor unit 2 of the floor-mounted air conditioner. The indoor unit 2 has an indoor control device 200 including a microcomputer and an input / output circuit. The indoor control device 200 drives the indoor fan 18 (shown in FIG. 4) based on a command signal from a remote controller (not shown) and detection signals from the indoor temperature sensor (not shown) and the refrigerant sensor 60. The fan motor 26 and the shutter drive unit 51 are controlled.

  Next, the operation | movement at the time of the refrigerant | coolant leak of the indoor control apparatus 200 of the said indoor unit 2 is demonstrated using the flowchart of FIG.

  First, when the process is started, it is determined whether or not leakage of the R32 refrigerant is detected by the refrigerant sensor 60 in step S1. If it is determined in step S1 that the refrigerant sensor 60 has detected leakage of the R32 refrigerant, the process proceeds to step S2. If the refrigerant sensor 60 determines that leakage of the R32 refrigerant has not been detected, step S1 is repeated.

  Next, it is determined whether or not the vehicle is operating in step S2. That is, it is determined whether or not a cooling operation or a heating operation is being performed. And if it determines with driving | running | working at step S2, it will progress to step S3, will stop driving | operation, and will progress to step S4.

  On the other hand, if it is determined in step S2 that the vehicle is not in operation, that is, the operation is stopped, the process proceeds to step S4.

  In step S4, the indoor controller 200 controls the shutter drive unit 51 to close the shutter 50 (opening / closing member) and close the lower air outlet 32b (lower opening).

  Next, it progresses to step S5 and alert | reports to a user that refrigerant | coolant leakage has generate | occur | produced by the buzzer, an audio | voice, and / or blinking of the LED display part.

  According to the indoor unit of the floor-type air conditioner having the above-described configuration, the lower air outlet 32b (lower opening) is in the open state in the operation stopped state (the indoor fan 18 is stopped). When the R32 refrigerant, which is a slightly flammable refrigerant, leaks from the connection portion between the indoor heat exchanger 15 and the refrigerant pipe in the main casing (the bottom frame 31 and the front grill 32) in this operation stop state, it is arranged in the main casing. When the leakage of the R32 refrigerant is detected by the refrigerant sensor 60, the indoor control device 200 controls the shutter drive unit 51 that drives the shutter 50 (opening / closing member), and the lower air outlet 32b (lower opening) is closed. To. By doing so, the R32 refrigerant gas is prevented from flowing out to the floor surface via the lower suction port located at the lowest position in the main body casing, and the opening portion (including the upper air outlet 32a) located at a relatively high position in the main body casing. ), The R32 refrigerant gas heavier than air flows out and falls, so that the diffusion of the R32 refrigerant gas is promoted before dropping to the floor surface. Thereby, it is possible to prevent the slightly flammable R32 refrigerant gas from staying in the vicinity of the indoor floor and increasing the gas concentration.

  When the refrigerant sensor 60 detects leakage of the R32 refrigerant during the cooling operation (or during the heating operation), the indoor control device 200 stops the cooling operation (or the heating operation), and then stops the shutter by the indoor control device 200. The shutter drive unit 51 that drives 50 (opening / closing member) is controlled to close the lower air outlet 32b (lower opening). Here, when the cooling operation or the heating operation is stopped, the indoor fan 18 is also stopped. However, the R32 refrigerant is operated by operating the indoor fan 18 and blowing it from the upper outlet a for a predetermined time from the detection of leakage of the R32 refrigerant. Gas diffusion may be promoted.

  Here, the detection of the R32 refrigerant leak by the refrigerant sensor 60 detects the refrigerant leak when the output signal level of the refrigerant sensor 60 exceeds a predetermined threshold, but the refrigerant leak detection method based on the output signal of the refrigerant sensor 60 is as follows. Not limited to this.

  When the leakage of the R32 refrigerant is detected by the refrigerant sensor 60, the shutter 50 (opening / closing member) is closed and the user is alerted by a notification means such as a buzzer, sound and / or blinking of the LED display.

  As described above, when the R32 refrigerant leaks from the main body casing, the leakage outlet to the outside is raised from the floor surface to promote the diffusion of the refrigerant, thereby reducing the risk associated with the leakage of the R32 refrigerant. Note that once the R32 refrigerant diffuses when it leaks into the room, it does not collect again on the floor side of the room and the refrigerant gas concentration does not increase.

  Further, when the refrigerant sensor 60 detects the leakage of the slightly flammable R32 refrigerant, the indoor control device 200 controls the flap 34 (upper opening adjustment member) to detect the leakage of the R32 refrigerant. By expanding the opening area of the outlet 32a (upper opening), the R32 refrigerant gas easily flows out from the upper outlet 32a (upper opening) at a high position of the main body casing, and therefore flows out of the upper outlet 32a (upper opening). R32 refrigerant gas can be effectively diffused. The flap 34 (upper opening adjusting member) has a function of adjusting the opening area of the upper outlet 32a (upper opening).

  Further, when the shutter 50 as the opening / closing member also serves as an air outlet damper for opening and closing the lower air outlet 32b (lower opening) during operation, when the refrigerant sensor 60 detects leakage of the R32 refrigerant, The lower air outlet 32b (lower opening) can be closed by the shutter 50 (opening / closing member) that also serves as the air outlet damper.

  In addition, by using a single refrigerant composed of slightly flammable R32 or a mixed refrigerant mainly composed of R32 as the flammable refrigerant, R32 has a low ozone destruction coefficient and a global warming coefficient GWP. As a result, the coefficient of performance COP can be improved and the energy consumption can be reduced.

  In the above embodiment, a slightly flammable single refrigerant of R32 or a mixed refrigerant mainly composed of R32 is used as the flammable refrigerant. However, the present invention is not limited to this, and a floor using other flammable refrigerants is used. The present invention may be applied to an indoor unit of a stationary air conditioner.

  In the above-described embodiment, the indoor unit 2 of a floor-mounted air conditioner having an air supply / humidifying function has been described. The present invention may be applied, and the present invention may be applied to an indoor unit of a floor type air conditioner having at least one of an air supply function and an exhaust function.

  Moreover, although the said embodiment demonstrated the indoor unit 2 of the floor-mounted air conditioner which provided the upper blower outlet 32a as an upper side opening and provided the lower blower outlet 32b as a lower side opening, the upper side opening and lower side opening were demonstrated. May be a suction port, and the present invention may be applied to an indoor unit of a large floor type air conditioner having an upper opening as a blow-out port and a lower opening as a suction port.

  Moreover, in the said embodiment, although the indoor unit 2 of the floor type air conditioner to which the humidification unit 42 was connected was demonstrated, a humidification unit does not need to be.

  Although specific embodiments of the present invention have been described, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Outdoor unit 2 ... Indoor unit 11 ... Compressor 12 ... Four-way switching valve 13 ... Outdoor heat exchanger 14 ... Electric expansion valve 15 ... Indoor heat exchanger 16 ... Accumulator 17 ... Outdoor fan 18 ... Indoor fan 21,22 ... Shut-off valve 26 ... Fan motor 27 ... Bell mouth 28 ... Drain pan 31 ... Bottom frame 32 ... Front grill 32a ... Upper outlet 32b ... Lower outlet 33 ... Suction panel 33a ... Upper inlet 33b ... Lower inlet 33c ... Side Direction suction port 34 ... flap 40 ... duct part 40a ... indoor side opening 40b ... hose connection part 41 ... humidification hose 42 ... humidification unit 50 ... shutter 51 ... shutter drive part 60 ... refrigerant sensor 100 ... outdoor control device 200 ... indoor control Equipment L1, L2 ... Communication piping

Claims (4)

A body casing (31, 32);
An indoor heat exchanger (15) disposed in the main casing (31, 32) and through which a flammable refrigerant flows;
A blower fan (18) which is disposed in the main casing (31, 32) and blows out the air sucked through the indoor heat exchanger (15);
An upper opening (32a) provided in the main casing (31, 32) and serving as a blow-out port or a suction port of the blower fan (18);
A lower opening (32b) provided in the main casing (31, 32) and serving as a blow-out port or a suction port of the blower fan (18);
A refrigerant sensor (60) disposed in the main casing (31, 32) for detecting leakage of the combustible refrigerant;
An opening and closing member (50) for opening and closing the lower opening (32b);
A control device (200) for controlling the blower fan (18) and the opening / closing member (50);
The control device (200) controls the open / close member (50) to close the lower opening (32b) when the refrigerant sensor (60) detects leakage of the combustible refrigerant. An indoor unit for floor-mounted air conditioners. In the indoor unit of a floor-standing air conditioner according to claim 1,
An upper opening adjustment member (34) for adjusting the opening area of the upper opening (32a);
When the control device (200) detects the leakage of the combustible refrigerant by the refrigerant sensor (60), the control device (200) controls the upper opening adjustment member (34) before detecting the leakage of the combustible refrigerant. Is an indoor unit of a floor-mounted air conditioner characterized in that the opening area of the upper opening (32a) is increased. The floor unit type air conditioner indoor unit according to claim 1 or 2,
The lower opening (32b) is an outlet for blowing out air from the blower fan (18),
The floor unit type air conditioner indoor unit, wherein the opening / closing member (50) also serves as a blower outlet damper for opening and closing the lower opening (32b) which is the blower outlet. In the indoor unit of a floor-mounted air conditioner according to any one of claims 1 to 3,
An indoor unit of a floor type air conditioner using a single refrigerant composed of R32 or a mixed refrigerant mainly composed of R32 as the combustible refrigerant.

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