TECHNICAL FIELD
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The present disclosure relates to a refrigeration cycle device using a flammable refrigerant.
BACKGROUND ART
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JP 2023-170657 A discloses a refrigeration cycle device that uses a flammable refrigerant.
SUMMARY
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An object of the present disclosure is to provide a refrigeration cycle device having a structure provided for a case where a flammable refrigerant leaks.
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In order to achieve the above object, according to an aspect of the present disclosure, a refrigeration cycle device is provided that includes:
- a casing including an internal space;
- a partition plate that is provided in the casing and divides the internal space into an air blowing chamber and a machine chamber;
- a heat exchanger disposed in the air blowing chamber;
- a fan disposed in the air blowing chamber; and
- a compressor that is disposed in the machine chamber, and compresses and discharges a flammable refrigerant heavier than air,
- wherein the casing includes a refrigerant discharge hole that communicates between a lower portion of the machine chamber and an outside of the casing,
- in addition to the refrigerant discharge hole, a through hole or a gap that communicates between the machine chamber and the outside of the casing exists in the casing, and
- a flow path cross-sectional area of the refrigerant discharge hole is larger than a flow path cross-sectional area of each of the through holes or the gaps other than the refrigerant discharge hole.
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According to the present disclosure, it is possible to provide a refrigeration cycle device having a structure provided for a case where a flammable refrigerant leaks.
BRIEF DESCRIPTION OF DRAWINGS
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- Fig. 1 is a schematic configuration diagram of a refrigeration cycle device according to an embodiment of the present disclosure;
- Fig. 2 is a schematic perspective view of an outdoor unit of the refrigeration cycle device;
- Fig. 3 is a schematic cross-sectional view of the outdoor unit;
- Fig. 4 is a perspective view illustrating a refrigerant discharge hole provided with an example of a mesh structure;
- Fig. 5 is a perspective view illustrating the refrigerant discharge hole provided with another example of a mesh structure;
- Fig. 6 is a cross-sectional view illustrating the refrigerant discharge hole provided with an example of a water stop structure; and
- Fig. 7 is a cross-sectional view illustrating the refrigerant discharge hole provided with another example of a water stop structure.
DETAILED DESCRIPTION
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A refrigeration cycle device according to one aspect of the present disclosure includes: a casing including an internal space; a partition plate that is provided in the casing and divides the internal space into an air blowing chamber and a machine chamber; a heat exchanger disposed in the air blowing chamber; a fan disposed in the air blowing chamber; and a compressor that is disposed in the machine chamber, and compresses and discharges a flammable refrigerant heavier than air, in which the casing includes a refrigerant discharge hole that communicates a lower portion of the machine chamber with an outside of the casing, in addition to the refrigerant discharge hole, a through hole or a gap that communicates the machine chamber with the outside of the casing exists in the casing, and a flow path cross-sectional area of the refrigerant discharge hole is larger than a flow path cross-sectional area of each of the through holes or the gaps other than the refrigerant discharge hole.
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According to such an aspect, it is possible to provide a refrigeration cycle device having a structure provided for a case where a flammable refrigerant leaks.
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For example, the refrigerant discharge hole may be provided in a portion of a bottom surface of the casing on a side of the machine chamber.
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For example, it is preferable that the flow path cross-sectional area of the refrigerant discharge hole be larger than a sum of flow path cross-sectional areas of the through holes or the gaps other than the refrigerant discharge hole.
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For example, when a drain discharge hole that communicates the air blowing chamber with the outside of the casing is formed in a portion of the bottom surface of the casing on a side of the air blowing chamber, an opening position of the refrigerant discharge hole on an inner side of the casing may be higher than an opening position of the drain discharge hole on an inner side of the casing.
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For example, when a drain groove is formed from the air blowing chamber to the machine chamber passing below the partition plate, at the bottom surface of the casing, an opening of the drain discharge hole may be formed inside the drain groove, and an opening of the refrigerant discharge hole may be formed outside the drain groove.
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For example, it is preferable that the opening position of the refrigerant discharge hole be higher than the opening position of the drain discharge hole by 15 mm or more.
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For example, a mesh structure may be provided on the opening of the refrigerant discharge hole.
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For example, a water stop structure may be provided on the opening of the refrigerant discharge hole.
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For example, a hose may be connected, as the water stop structure, to the opening of the refrigerant discharge hole on an outer side of the casing.
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For example, the refrigeration cycle device may further include an electric box having a sealed structure disposed in the machine chamber.
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Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.
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Fig. 1 is a schematic configuration diagram of the refrigeration cycle device according to the embodiment of the present disclosure.
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As illustrated in Fig. 1, a refrigeration cycle device 10 according to the present embodiment is a so-called air conditioner, and the refrigeration cycle device 10 includes an indoor unit 12 disposed inside the room and an outdoor unit 14 disposed outside the room.
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As illustrated in Fig. 1, the indoor unit 12 includes a casing 16 installed inside the room, a heat exchanger 18 that is disposed in the casing 16 and exchanges heat with indoor air, and a cross-flow fan 20 that generates a flow of indoor air so that the indoor air passes through the heat exchanger 18. When the cross-flow fan 20 rotates, the indoor air flows into the casing 16 and passes through the heat exchanger 18. The air having passed through the heat exchanger 18 is blown into the room from the casing 16.
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As illustrated in Fig. 1, the outdoor unit 14 includes a casing 22 installed outside the room, a heat exchanger 24 that is disposed in the casing 22 and exchanges heat with outdoor air, an axial fan 26 that generates a flow of outdoor air so that the outdoor air passes through the heat exchanger 24, and a compressor 28 that compresses and discharges a refrigerant passing through the heat exchangers 18 and 24. The heat exchanger 18, the heat exchanger 24, and the compressor 28 are connected via a refrigerant pipe 30. An expansion valve 32 that decompresses the refrigerant and a four-way valve 34 that changes a flow direction of the refrigerant are disposed on the refrigerant pipe 30.
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As illustrated in Fig. 1, an internal space of the casing 22 of the outdoor unit 14 is divided into an air blowing chamber R1 and a machine chamber R2 by a partition plate 36. The heat exchanger 24 and the axial fan 26 are disposed in the air blowing chamber R1. The compressor 28, the expansion valve 32, and the four-way valve 34 are disposed in the machine chamber R2. When the axial fan 26 rotates, the outdoor air flows into the air blowing chamber R1 and passes through the heat exchanger 24. The outdoor air having passed through the heat exchanger 24 is blown out to the outside of the casing 22. Note that, unlike the air blowing chamber R1 through which the outdoor air passes, the machine chamber R2 is substantially sealed to the extent that foreign matter such as rainwater, insects, and small animals cannot enter from the outside.
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During a cooling operation, the refrigerant is delivered from the compressor 28, sequentially passes through the four-way valve 34, the heat exchanger 24 of the outdoor unit 14, the expansion valve 32, and the heat exchanger 18 of the indoor unit 12, and returns to the compressor 28. During a heating operation, the refrigerant is delivered from the compressor 28, sequentially passes through the four-way valve 34, the heat exchanger 18 of the indoor unit 12, the expansion valve 32, and the heat exchanger 24 of the outdoor unit 14, and returns to the compressor 28. The flow of the refrigerant during the cooling operation and the flow of the refrigerant during the heating operation are switched by the four-way valve 34.
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Further features of the refrigeration cycle device 10 will be described below. The features described below are features required for the refrigeration cycle device to use a flammable refrigerant heavier than air. For example, the refrigerant includes a hydrocarbon refrigerant such as propane (R-290), isobutane (R-600a), or propylene (R-1270). Alternatively, the refrigerant may be a fluorine-based refrigerant such as HFO-1234yf or R-32. Moreover, a mixed refrigerant of these refrigerants may be used. In the present embodiment, a flammable refrigerant is used as the refrigerant. The flammable refrigerant includes a slightly or strongly flammable refrigerant. Furthermore, in the present embodiment, a refrigerant having a specific gravity larger than that of air is used as the refrigerant.
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Fig. 2 is a schematic perspective view of the outdoor unit of the air conditioner. Fig. 3 is a schematic cross-sectional view of the outdoor unit. Note that, in Fig. 2, the axial fan 26, the compressor 28, the expansion valve 32, the four-way valve 34, and the refrigerant pipe 30 are not illustrated.
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As illustrated in Fig. 2, a refrigerant discharge hole 22b is formed in a bottom plate 22a constituting a bottom surface of the casing 22. Specifically, the refrigerant discharge hole 22b is formed in a portion of the bottom plate 22a on a side of the machine chamber R2. The refrigerant discharge hole 22b is a through hole through which the refrigerant leaking from the machine chamber R2, for example, the refrigerant leaking from the compressor 28 is naturally discharged to the outside of the casing 22. That is, the flammable refrigerant leaking in the machine chamber R2 and heavier than air is naturally discharged below the casing 22 through the refrigerant discharge hole 22b. Note that the casing 22 is installed on an installation reference surface such as a floor surface of a veranda via stands 38, so that a space through which the flammable refrigerant flows out exists between the casing 22 and the installation reference surface.
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Such a refrigerant discharge hole 22b has been devised on the assumption of the inventor.
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The assumption of the inventor will be specifically described. First, when the flammable refrigerant leaks in the machine chamber R2, the machine chamber R2 having a higher degree of sealing than the air blowing chamber R1 is filled with the flammable refrigerant. When the machine chamber R2 is filled with the flammable refrigerant to some extent, the flammable refrigerant substantially jets through the through hole and the gap that directly communicate between the machine chamber R2 and the outside of the casing 22 and that inevitably exist due to the structure and manufacturing. The "through hole and gap" herein refers to, for example, a gap between the refrigerant pipe 30 and a hole provided in the casing 22 through which the refrigerant pipe 30 passes, a gap between the bottom plate 22a and a side plate 22c constituting the casing 22, a gap between a top plate 22d and the side plate 22c, and a through hole, such as a female screw hole, and a gap that can be made due to the structure and manufacturing.
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Such jetting of the flammable refrigerant from the through hole and the gap continues at a constant flow velocity and a constant high concentration. When an ignition source exists in the vicinity of the gap, the jetted flammable refrigerant having a high concentration may ignite and burn. When the flammable refrigerant continues to jet from the gap at a constant flow velocity and the flammable refrigerant is maintained at a concentration suitable for ignition in the vicinity of the gap, the flammable refrigerant is highly likely to ignite.
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Once the flammable refrigerant jetting out from the gap ignites, since the flammable refrigerant continuously jets out from the gap, the flammable refrigerant continues to burn in the vicinity of the gap. That is, like a gas burner, the flame continues to emit from the gap. Note that the flammable refrigerant filled in the machine chamber R2 does not spread fire because the concentration of the flammable refrigerant is too high (that is, oxygen required for combustion is insufficient).
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If there is a flammable object (for example, clothes dried on a veranda on which the outdoor unit is installed) in the vicinity of the flame that continues to emit from such a gap, the flame may eventually spread to the object and eventually cause a fire.
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Based on such an assumption, the inventor has found a need to discharge the flammable refrigerant to the outside of the machine chamber R2 before the machine chamber R2 is filled with the flammable refrigerant leaking in the machine chamber R2. The inventor has devised the refrigerant discharge hole 22b for naturally discharging the flammable refrigerant leaking in the machine chamber R2.
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The "natural discharge" referred to herein is not forced discharge using a fan or the like, but discharge utilizing a property that the flammable refrigerant heavier than air moves downward by itself due to gravity. In a case where the flammable refrigerant is forcibly discharged using a fan or the like, for example, if the flammable refrigerant leaks in the machine chamber R2 when a power failure occurs due to an earthquake or the like, the fan cannot be used due to the power failure. Therefore, there is a possibility that the leaking flammable refrigerant is not appropriately discharged to the outside of the casing and fills the machine chamber R2.
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In order to naturally discharge the flammable refrigerant, which is leaking in the machine chamber R2 and heavier than air, the refrigerant discharge hole 22b communicates a lower portion of the machine chamber R2 with the outside of the casing 22 as illustrated in Figs. 2 and 3. In the case of the present embodiment, the refrigerant discharge hole 22b is provided in the bottom plate 22a constituting the bottom surface of the casing 22. That is, the refrigerant discharge hole 22b communicates the lower portion of the machine chamber R2 with a space below the bottom plate 22a of the casing 22. Thus, the flammable refrigerant leaking in the machine chamber R2 moves downward in the machine chamber R2 and flows to the outside of the casing 22 through the refrigerant discharge hole 22b of the bottom plate 22a. As a result, filling of the machine chamber R2 with the flammable refrigerant is suppressed, and jetting of the flammable refrigerant having a high concentration through the through hole and the gap, other than the refrigerant discharge hole 22b, that communicate the machine chamber R2 with the outside of the casing 22, is suppressed. In addition, such a refrigerant discharge hole 22b causes the flammable refrigerant leaking in the machine chamber R2 to be discharged below the casing 22 where the ignition source is less likely to exist as compared with other places.
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Note that it is desirable that the refrigerant discharge hole 22b exist below a portion where leakage of the flammable refrigerant is assumed, such as a U-bend of the heat exchanger 24 or a welded portion of an electric valve. As a result, the leaking flammable refrigerant is discharged to the outside of the casing 22 through the refrigerant discharge hole 22b immediately after leaking. In addition, in order to more efficiently discharge the flammable refrigerant through the refrigerant discharge hole 22b, an air supply hole for communicating an upper portion of the machine chamber R2 with the outside of the casing 22 may be provided in the casing 22. In this case, while the flammable refrigerant flows out of the machine chamber R2 through the refrigerant discharge hole 22b, the outdoor air flows into the machine chamber R2 through the air supply hole. As a result, the machine chamber R2 is substantially maintained at atmospheric pressure, and the flammable refrigerant leaking in the machine chamber R2 is discharged to the outside of the machine chamber R2 through the refrigerant discharge hole 22b without stagnation.
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In addition, in order to naturally discharge the flammable refrigerant leaking in the machine chamber R2 to the outside of the casing 22 through the refrigerant discharge hole 22b, a flow path cross-sectional area of the refrigerant discharge hole 22b is made to be larger than a flow path cross-sectional area of each of the through hole and the gap, other than the refrigerant discharge hole 22b, that communicate the machine chamber R2 with the outside of the casing 22. That is, the refrigerant discharge hole 22b has the largest flow path cross-sectional area among the plurality of flow paths that communicate between the machine chamber R2 and the outside of the casing 22 and that the flammable refrigerant can pass through. As a result, the flammable refrigerant is naturally discharged to the outside of the casing 22 preferentially through the refrigerant discharge hole 22b while being prevented from being jetted from the through hole and the gap. That is, the refrigerant discharge hole 22b has a flow path cross-sectional area having a size capable of suppressing filling of the machine chamber R2 with the flammable refrigerant. Note that the flow path cross-sectional area of each of the through hole and the gap, other than the refrigerant discharge hole 22b, that communicate between the machine chamber R2 and the outside of the casing 22, can be calculated based on design dimensions and tolerances.
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More specifically, it is preferable that the flow path cross-sectional area of the refrigerant discharge hole 22b be larger than the sum of flow path cross-sectional areas of the through hole and the gap, other than the refrigerant discharge hole 22b, that communicate between the machine chamber R2 and the outside of the casing 22. As a result, almost all of the flammable refrigerant is naturally discharged to the outside of the casing 22 through the refrigerant discharge hole 22b while more reliably preventing the flammable refrigerant from being jetted from the through hole and the gap.
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In the case of the present embodiment, as illustrated in Fig. 2, the bottom plate 22a of the casing 22 is provided with a drain groove 22e. In the air blowing chamber R1, the drain groove 22e is located below the heat exchanger 24. In addition, the drain groove 22e extends from the air blowing chamber R1 to the machine chamber R2 passing below the partition plate 36. Furthermore, in a portion of the drain groove 22e located at the air blowing chamber R1, a drain discharge hole 22f that communicates between the air blowing chamber R1 and the outside of the casing 22 is provided. By the drain groove 22e and the drain discharge hole 22f, liquid (that is, water) condensed on a surface of the heat exchanger 24 and dropped on the bottom plate 22a of the casing 22 is discharged to the outside of the casing 22. In addition, liquid such as rainwater that has entered the air blowing chamber R1 through a suction port and a blowout port through which the outdoor air passes while communicating between the air blowing chamber R1 and the outside of the casing 22, is discharged to the outside of the casing 22.
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As illustrated in Fig. 3, an opening position of the drain discharge hole 22f on an inner side of the casing 22 is lower than an opening position of the refrigerant discharge hole 22b on the inner side of the casing 22. That is, the opening position of the refrigerant discharge hole 22b is higher than the opening position of the drain discharge hole 22f by the height difference H. Therefore, as illustrated in Fig. 2, the refrigerant discharge hole 22b is formed outside the drain groove 22e.
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As described above, with respect to the opening position inside the casing 22, the reason why the refrigerant discharge hole 22b is higher than the drain discharge hole 22f is to prevent rainwater or liquid such as water condensed in the heat exchanger 24 from being discharged to the outside of the casing 22 through the refrigerant discharge hole 22b. If the flammable refrigerant leaks in the machine chamber R2 while the liquid is being discharged through the refrigerant discharge hole 22b, the flammable refrigerant leaking through the refrigerant discharge hole 22b may not be properly discharged to the outside of the casing 22. In addition, in a case where the refrigerant discharge hole 22b is lower than the drain discharge hole 22f, the refrigerant discharge hole 22b is blocked by dead leaves, dust, and the like carried by the drain, and there is a possibility that the discharge of the refrigerant through the refrigerant discharge hole 22b is hindered.
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Note that there may be a case where the flammable refrigerant leaking in the machine chamber R2 is made to flow out to the air blowing chamber R1 through the drain groove 22e, and then the flammable refrigerant in the air blowing chamber R1 is discharged to the outside of the casing 22 through the drain discharge hole 22f. In this case, it is necessary to increase a flow path cross-sectional area of the drain groove 22e (in particular, the flow path cross-sectional area below the partition plate 36) in order to make the flammable refrigerant leaking in the machine chamber R2 to flow out to the air blowing chamber R1 through the drain groove 22e. However, when the flow path cross-sectional area of the drain groove 22e is increased, a part of the outdoor air blown by the axial fan 26 flows into the machine chamber R2 through the drain groove 22e. As a result, heat exchange efficiency between the outdoor air and the heat exchanger 24 decreases. In addition, in a case where the use period of the refrigeration cycle device 10 is long, dust or the like may be accumulated in the drain groove 22e. In this case, a substantial flow path cross-sectional area of the drain groove 22e decreases, and there is a possibility that the flammable refrigerant leaking in the machine chamber R2 cannot appropriately flow into the air blowing chamber R1 via the drain groove 22e. In consideration of these, the flammable refrigerant leaking in the machine chamber R2 is discharged to the outside of the casing 22 through the refrigerant discharge hole 22b that communicates between the machine chamber R2 and the outside of the casing 22 without passing through the air blowing chamber R1.
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In addition, there is a case where the outdoor unit 14 is installed on an installation reference surface that is inclined to an allowable extent. In consideration of this case, the height difference H between the inner opening of the refrigerant discharge hole 22b and the inner opening of the drain discharge hole 22f is set to 15 mm or more.
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As described above, the flow path cross-sectional area of the refrigerant discharge hole 22b is made to be larger than the flow path cross-sectional area of each of the opening and the gap, other than the refrigerant discharge hole 22b, that communicate between the machine chamber R2 and the outside of the casing 22. Therefore, depending on the installation environment of the outdoor unit 14, there is a possibility that foreign matter enters the machine chamber R2 through the refrigerant discharge hole 22b.
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Fig. 4 is a perspective view illustrating the refrigerant discharge hole provided with an example of a mesh structure. Fig. 5 is a perspective view illustrating the refrigerant discharge hole provided with another example of a mesh structure.
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As illustrated in Figs. 4 and 5, in order to suppress entry of organisms such as insects and small animals into the machine chamber R2, a meshed lid member 40 or 42 is attached as a mesh structure to the refrigerant discharge hole 22b so as to cover the opening of the refrigerant discharge hole 22b. The lid member 40 includes a plurality of slot-shaped through holes through which the flammable refrigerant leaking in the machine chamber R2 can pass and through which organisms such as insects and small animals cannot pass. The lid member 42 includes a plurality of circular through holes through which the flammable refrigerant can pass and through which organisms cannot pass. Note that the lid members 40 and 42 may be provided at either the inner opening or the outer opening of the refrigerant discharge hole 22b.
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Fig. 6 is a cross-sectional view illustrating the refrigerant discharge hole provided with an example of a water stop structure. Fig. 7 is a cross-sectional view illustrating a refrigerant discharge hole provided with another example of a water stop structure.
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As illustrated in Figs. 6 and 7, in the present embodiment, the refrigerant discharge hole 22b is provided in the bottom plate 22a constituting the bottom surface of the casing 22. Therefore, in the case of rain, there is a possibility that rain rebounding from the ground contact reference surface enters the machine chamber R2 through the refrigerant discharge hole 22b. Thus, as illustrated in Fig. 6, a water stop cap 44 is provided on the refrigerant discharge hole 22b so as to cover the opening of the refrigerant discharge hole 22b at a distance from the opening. In addition, as illustrated in Fig. 7, as a water stop structure, a hose 46 is connected to the opening of the refrigerant discharge hole 22b on the outer side of the casing 22.
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Note that the mesh structure (lid members 40 and 42) illustrated in Fig. 4 or Fig. 5 and the water stop structure (water stop cap 44 and hose 46) illustrated in Fig. 6 or Fig. 7 can be used in combination. For example, the lid member 40 illustrated in Fig. 4 or the lid member 42 illustrated in Fig. 5, and the hose 46 illustrated in Fig. 7 may be used in combination.
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In the case of the present embodiment, by providing the refrigerant discharge hole 22b, jetting of the flammable refrigerant having a high concentration from the through hole and the gap, other than the refrigerant discharge hole 22b, that communicate between the machine chamber R2 and the outside of the casing 22, is suppressed. As a result, ignition of the flammable refrigerant jetted at a high concentration by an ignition source existing outside the casing 22 is suppressed. However, the ignition source may also exist in the machine chamber R2. For example, a conductor portion through which a current flows on a control board that controls the compressor 28 can become an ignition source. As a countermeasure, as illustrated in Fig. 2, electric components that can become an ignition source such as a control board in the machine chamber R2 are provided in the machine chamber R2 in a state of being stored in an electric box 48 having a sealed structure.
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According to the present embodiment as described above, it is possible to provide a refrigeration cycle device having a structure provided for a case where a flammable refrigerant leaks, that is, a structure capable of suppressing ignition of the leaking flammable refrigerant.
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Although the present disclosure has been described above with reference to the above-described embodiment, the present disclosure is not limited to the above-described embodiment.
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For example, in the case of the above-described embodiment, as illustrated in Fig. 2, the refrigerant discharge hole 22b is formed in the bottom surface (bottom plate 22a) of the casing 22 and faces the vertical direction. However, the embodiment of the present disclosure is not limited thereto. A refrigerant discharge hole 22b may be formed in a side surface (side plate 22c) of a casing 22 and face in the horizontal direction. The refrigerant discharge hole 22b needs to at least communicate between a lower portion of a machine chamber R2 and the outside of the casing 22.
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That is, in a broad sense, a refrigeration cycle device according to the embodiment of the present disclosure includes: a casing including an internal space; a partition plate that is provided in the casing and divides the internal space into an air blowing chamber and a machine chamber; a heat exchanger disposed in the air blowing chamber; a fan disposed in the air blowing chamber; and a compressor that is disposed in the machine chamber, and compresses and discharges a flammable refrigerant heavier than air, in which the casing includes a refrigerant discharge hole that communicates a lower portion of the machine chamber with an outside of the casing, in addition to the refrigerant discharge hole, a through hole or a gap that communicates the machine chamber with the outside of the casing exists in the casing, and a flow path cross-sectional area of the refrigerant discharge hole is larger than a flow path cross-sectional area of each of the through holes or the gaps other than the refrigerant discharge hole.
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The present disclosure is applicable to a refrigeration cycle device that uses a flammable refrigerant heavier than air.