Indoor unit and air conditioner including indoor unit

Abstract

An indoor unit of a ceiling embedded type, includes: a case having a suction port; a heat exchanger; a fan configured to suck indoor air via the suction port and send the indoor air thus sucked to the heat exchanger; an air guide member configured to guide the indoor air sucked into the fan, dividing an internal space of the case into a first space and a second space disposed downstream in an air flow with respect to the first space, and having a passage allowing a refrigerant to pass through from the second space to the first space; and a refrigerant sensor disposed in the passage closer to the first space than to the second space and configured to detect the refrigerant having passed the passage.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This is a continuation application of International Patent Application No. PCT / JP2024 / 014783, filed Apr. 12, 2024, and claims priority to Japanese Patent Application No. 2023-170450, filed Sep. 29, 2023. The contents of these priority applications are incorporated herein by reference.TECHNICAL FIELD

[0002] The present disclosure relates to an air conditioner and particularly relates to an indoor unit including a refrigerant sensor configured to detect a refrigerant leaked from a refrigerant circuit.BACKGROUND

[0003] Patent Literature 1 (WO 2019-234902) discloses an indoor unit to be embedded in a ceiling. This indoor unit includes a refrigerant sensor configured to detect a leaked refrigerant. The refrigerant sensor is disposed near a suction port of the indoor unit, and detects a refrigerant component contained in the air sucked into the indoor unit. This refrigerant component is the refrigerant that has leaked from the refrigerant circuit, then come out to the indoor space, and been diluted with the indoor air.SUMMARY

[0004] An indoor unit according to a first aspect is of a ceiling embedded type. The indoor unit includes a case, a heat exchanger, a fan, an air guide member, a passage, and a refrigerant sensor. The case has a suction port. The fan sucks indoor air via the suction port and sends the indoor air thus sucked to the heat exchanger. The air guide member guides the indoor air sucked into the fan. The air guide member divides an internal space of the case into a first space and a second space. The second space is disposed downstream of the first space in an air flow. The passage is provided in the air guide member. The passage allows a refrigerant to pass through from the second space to the first space. The refrigerant sensor is disposed closer to the first space in the passage. The refrigerant sensor is configured to detect the refrigerant having passed through the passage.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] FIG. 1 is a schematic view of an air conditioner 100.

[0006] FIG. 2 is a schematic view of an indoor unit 20.

[0007] FIG. 3 is a perspective view of the indoor unit 20.

[0008] FIG. 4 is a sectional view of the indoor unit 20.

[0009] FIG. 5 is a schematic view of a refrigerant sensor 60.

[0010] FIG. 6 is a perspective view of the refrigerant sensor 60 fixed to an air guide member 70.DETAILED DESCRIPTIONEmbodiments(1) Entire Configuration(1-1) Components Constituting Refrigerant Circuit

[0011] FIG. 1 depicts an air conditioner 100 according to one or more embodiments. The air conditioner 100 is constituted by an outdoor unit 10, an indoor unit 20, and a refrigerant pipe group 30 connecting the outdoor unit 10 and the indoor unit 20. The air conditioner 100 includes a refrigerant circuit for circulation of a refrigerant R.

[0012] The outdoor unit 10 includes, as components of the refrigerant circuit, a compressor 11, a four-way switching valve 12, an outdoor heat exchanger 13, an outdoor expansion valve 15, an accumulator 16, a liquid shutoff valve 17, and a gas shutoff valve 18.

[0013] The indoor unit 20 includes an indoor heat exchanger 23 as a component of the refrigerant circuit.

[0014] The refrigerant pipe group 30 includes a liquid connection pipe 31 and a gas connection pipe 32 as components of the refrigerant circuit.(1-2) Cooling Operation

[0015] A cooling operation is an operation in which the air conditioner 100 provides a user with cold heat.

[0016] The compressor 11 sucks a low-pressure gas refrigerant from an suction tube 11a and compresses it to generate a high-pressure gas refrigerant to be discharged from a discharge tube 11b. During the cooling operation, the four-way switching valve 12 achieves connection indicated by solid lines. The outdoor heat exchanger 13 condenses the high-pressure gas refrigerant to generate a high-pressure liquid refrigerant. An outdoor fan 14 promotes heat exchange between the refrigerant and the air in the outdoor heat exchanger 13. The outdoor expansion valve 15 decompresses the high-pressure liquid refrigerant to generate a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant passes through the liquid shutoff valve 17 and the liquid connection pipe 31 to reach the indoor heat exchanger 23.

[0017] The indoor heat exchanger 23 evaporates the gas-liquid two-phase refrigerant to generate a low-pressure gas refrigerant, generating hot heat to be supplied to a user during this process. An indoor fan 24 promotes heat exchange between the refrigerant and the air in the indoor heat exchanger 23, and delivers, to a user, cold heat in the form of cool air. The low-pressure gas refrigerant passes through the gas connection pipe 32, the gas shutoff valve 18, and the four-way switching valve 12 to reach the accumulator 16.

[0018] The accumulator 16 separates a fluid component mixed in the low-pressure gas refrigerant and reserves the fluid component. The low-pressure gas refrigerant flowing out of the accumulator 16 is sucked from the suction tube 11a by the compressor 11.(1-3) Heating Operation

[0019] A heating operation in an operation in which the air conditioner 100 provides a user with hot heat.

[0020] The compressor 11 sucks a low-pressure gas refrigerant from an suction tube 11a and compresses it to generate a high-pressure gas refrigerant to be discharged from a discharge tube 11b. During heating operation, the four-way switching valve 12 achieves connection indicated by broken lines. The high-pressure gas refrigerant passes through the four-way switching valve 12, the gas shutoff valve 18, and the gas connection pipe 32 to reach the indoor heat exchanger 23.

[0021] The indoor heat exchanger 23 condenses the high-pressure gas refrigerant to generate a high-pressure liquid refrigerant, generating hot heat to be supplied to a user during this process. The indoor fan 24 promotes heat exchange between the refrigerant and the air in the indoor heat exchanger 23, and delivers, to a user, hot heat in the form of warm air. The high-pressure liquid refrigerant passes through the liquid connection pipe 31 and the liquid shutoff valve 17 to reach the outdoor expansion valve 15.

[0022] The outdoor expansion valve 15 decompresses the high-pressure liquid refrigerant to generate a low-pressure gas-liquid two-phase refrigerant. The outdoor heat exchanger 13 evaporates the low-pressure gas-liquid two-phase refrigerant to generate a low-pressure gas refrigerant. An outdoor fan 14 promotes heat exchange between the refrigerant and the air in the outdoor heat exchanger 13. The low-pressure gas refrigerant reaches the accumulator 16 via the four-way switching valve 12. The accumulator 16 separates a fluid component mixed in the low-pressure gas refrigerant and reserves the fluid component. The low-pressure gas refrigerant flowing out of the accumulator 16 is sucked from the suction tube 11a by the compressor 11.(2) Detailed Configuration of Indoor Unit 20

[0023] FIG. 2 is a schematic view of a structure of the indoor unit 20. The indoor unit 20 is designed to be embedded in a ceiling. The indoor unit 20 includes a case 50, the indoor heat exchanger 23, the indoor fan 24, an air guide member 70, a refrigerant sensor 60, and a drain pan 73.(2-1) Case 50

[0024] FIG. 3 is a perspective view of the indoor unit 20. This figure depicts, in an upper side, a lower surface of the indoor unit 20. This figure depicts, in a lower side, an upper surface of the indoor unit 20 as a portion to be embedded in a ceiling.

[0025] The case 50 accommodates components constituting the indoor unit 20 including the indoor heat exchanger 23 and the indoor fan 24. The case 50 is provided with a single suction port 51 for intake of air from an indoor space, and four blow-out ports 52 for supply of conditioned air into the indoor space. As depicted in FIG. 2, the suction port 51 is provided with a filter 53 configured to remove dust or dirt from intake air. FIG. 3 does not depict the filter 53.(2-2) Indoor Heat Exchanger 23

[0026] The indoor heat exchanger 23 depicted in FIG. 2 functions as an evaporator for the refrigerant R during the cooling operation and functions as a condenser for the refrigerant R during the heating operation. The indoor heat exchanger 23 exemplarily includes a plurality of heat transfer tubes and a fin. An air flow passing through the indoor heat exchanger 23 exchanges heat with the refrigerant R.(2-3) Indoor Fan 24

[0027] When the indoor fan 24 operates, indoor air is sucked via the suction port 51 and passes through the filter 53 during the process. A flow of the air then passes through the indoor heat exchanger 23 and exchanges heat with the refrigerant R to be conditioned. Conditioned air flows from the indoor heat exchanger 23 to the blow-out ports 52 so as to blow into the indoor space.(2-4) Air Guide Member 70

[0028] The air guide member 70 depicted in FIG. 2 guides the indoor air sucked into the indoor fan 24. The air guide member 70 includes a bell mouth 71 and a plate 72. The bell mouth 71 is a tubular member provided to concentrate an air flow path to the indoor fan 24. The plate 72 is a plate member having a tabular or bowl shape and provided to protect components constituting the indoor unit 20 disposed in a region that may be exposed via the blow-out ports 52. The plate 72 is disposed adjacent to the bell mouth 71 and is connected to the bell mouth 71.

[0029] The air guide member 70 divides an internal space of the case 50 into a first space 77 and a second space 78. The first space 77 is positioned upstream of the air flow and occupies a region expanding from the suction port 51 to the indoor fan 24. The second space 78 is positioned downstream of the air flow and occupies a region expanding from the indoor fan 24 to the blow-out ports 52.

[0030] FIG. 4 is a sectional view of the indoor unit 20. This figure indicates that the bell mouth 71 has a slant surface portion provided continuously to a horizontal portion of the plate 72. The air guide member 70 is provided with a passage 75 allowing the first space 77 and the second space 78 to communicate with each other. The actual form of the passage 75 may be a hole or a cutout provided in the bell mouth 71 or the plate 72. The passage 75 allows the refrigerant R leaked from the refrigerant circuit, such as the indoor heat exchanger 23, to pass through from the second space 78 to the first space 77. The passage 75 depicted in FIG. 4 has an upper end 75a, which is a surface of the air guide member 70 located on the side of the second space 78.(2-5) Refrigerant Sensor 60

[0031] The refrigerant sensor 60 depicted in FIG. 4 detects the refrigerant R leaked from the refrigerant circuit. The refrigerant sensor 60 is disposed at the passage 75 on the side of the first space 77. The refrigerant sensor 60 is disposed below the passage 75 and oriented upward. The refrigerant sensor 60 detects the refrigerant R that has passed through the passage 75.

[0032] The air guide member 70 has an upper end substantially as high as an upper end of the indoor heat exchanger 23. The air guide member 70 has a lower end substantially as high as a lower end of the indoor heat exchanger 23. The air guide member 70 can thus serve as a barrier against the refrigerant R that leaks from the indoor heat exchanger 23 to reach the refrigerant sensor 60. The passage 75 provided in the air guide member 70 enables the refrigerant R to quickly reach the refrigerant sensor 60.

[0033] The components constituting the refrigerant circuit, such as the indoor heat exchanger 23 and pipes connected thereto, are mainly disposed in the second space 78. The refrigerant R leaked from the refrigerant circuit thus initially drifts in the second space 78. The specific gravity of the refrigerant R is heavier than that of air, and the refrigerant R can be R32. The refrigerant R drifting in the second space 78 then passes through the passage 75 due to gravity or the like to reach the refrigerant sensor 60. There is provided a sealing material 76 to seal a gap between a portion of the air guide member 70 adjacent to the passage 75 and the refrigerant sensor 60.

[0034] FIG. 5 depicts a structure of the refrigerant sensor 60. The refrigerant sensor 60 includes an upper case 61, a lower case 62, a circuit board 63, a refrigerant detecting element 64, a connector 65, and a wire 66. The upper case 61 is provided with a detection window 61a. The detection window 61a allows a refrigerant leaked outside the upper case 61 to reach the refrigerant detecting element 64. The lower case 62 is provided with a screwing through hole 62a. The circuit board 63 is equipped with the refrigerant detecting element 64 and the connector 65. The wire 66 extending from the connector 65 extends to an unillustrated electric component box.

[0035] FIG. 6 depicts the refrigerant sensor 60 fixed to the air guide member 70. The refrigerant sensor 60 is fixed to the air guide member 70 with use of a screw 67 attached to the screwing through hole 62a. (2-6) Drain Pan 73

[0036] The drain pan 73 depicted in FIG. 4 is a container configured to collect dew condensation water produced on a surface of the indoor heat exchanger 23. The dew condensation water thus collected is discarded outdoors via an unillustrated drainage path. The drain pan 73 is disposed adjacent to the air guide member 70. The drain pan 73 is disposed to face the lower end of the indoor heat exchanger 23. The drain pan 73 has a concave shape opened upward, and surrounds the lower end of the indoor heat exchanger 23. The drain pan 73 has a bottom 73a positioned lower than the upper end 75a of the passage 75.(3) Characteristics(3-1)

[0037] Generally, it takes time for detection of a leaked refrigerant once having passed through an indoor space. Furthermore, in order to detect the leaked refrigerant without passing through the indoor space, the refrigerant leaked from a refrigerant circuit disposed outside a bell mouth needs to reach a refrigerant sensor disposed inside the bell mouth. However, if there is adopted a refrigerant heavier than air, the refrigerant leaked from the refrigerant circuit needs to flow over the height of the bell mouth to reach the refrigerant sensor. It takes time for detection also in this case.

[0038] Regarding the above-mentioned embodiments, in contrast, the refrigerant R leaked into the second space 78 passes through the passage 75 to reach the refrigerant sensor 60. Accordingly, the leaked refrigerant R to be detected does not need to flow over the upper end of the air guide member 70, leading to quick detection of refrigerant leakage. In addition, the refrigerant sensor 60 is disposed on a lower surface of the case 50 to facilitate replacement, and maintenance is thus executed easily.(3-2)

[0039] The refrigerant R leaked from the refrigerant circuit descends toward the refrigerant sensor 60 directed upward, so that refrigerant leakage is detected more quickly.(3-3)

[0040] The bottom 73a of the drain pan 73 is positioned lower than the upper end 75a of the passage 75. Drain water leaking from around the bottom 73a of the drain pan 73 being cracked is thus less likely to reach the passage75. This inhibits the drain water from damaging the refrigerant sensor 60.(3-4)

[0041] The gap between the passage 75 and the refrigerant sensor 60 is sealed. This inhibits leakage of conditioned air to keep air conditioning efficiency.(3-5)

[0042] The filter 53 is provided so that dust or dirt contained in the indoor air sucked via the suction port 51 is less likely to enter the case 50. This inhibits accumulation of dust or dirt on the refrigerant sensor 60.(4) Modification Examples

[0043] The indoor unit 20 according to the above embodiments is designed to be embedded in a ceiling. Alternatively, the indoor unit 20 may be designed to be hung from a ceiling. Still alternatively, the indoor unit 20 may be of a wall mounted type or a floorstanding type.Conclusion

[0044] Although the disclosure has been described with respect to only a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that various other embodiments may be devised without departing from the scope of the present disclosure. Accordingly, the scope of the disclosure should be limited only by the attached claims.REFERENCE SIGNS LIST10: outdoor unit

[0046] 20: indoor unit

[0047] 23: indoor heat exchanger (heat exchanger)

[0048] 24: indoor fan (fan)

[0049] 50: case

[0050] 51: suction port

[0051] 52: blow-out port

[0052] 53: filter

[0053] 60: refrigerant sensor

[0054] 70: air guide member

[0055] 71: bell mouth

[0056] 72: plate

[0057] 73: drain pan

[0058] 73a: bottom

[0059] 75: passage

[0060] 75a: upper end

[0061] 76: sealing material

[0062] 77: first space

[0063] 78: second space

[0064] 100: air conditioner

[0065] R: refrigerantPatent Literature

[0066] Patent Literature 1: WO 2019-234902

Claims

1. An indoor unit of a ceiling embedded type, comprising:a case having a suction port;a heat exchanger;a fan configured to suck indoor air via the suction port and send the indoor air thus sucked to the heat exchanger;an air guide member:configured to guide the indoor air sucked into the fan,dividing an internal space of the case into a first space and a second space disposed downstream in an air flow with respect to the first space, andhaving a passage allowing a refrigerant to pass through from the second space to the first space; anda refrigerant sensor disposed in the passage closer to the first space than to the second space and configured to detect the refrigerant having passed the passage.

2. The indoor unit according to claim 1, wherein the refrigerant sensor is disposed in a lower portion of the passage and directed upward when the indoor unit is embedded in a ceiling.

3. The indoor unit according to claim 1, further comprisinga drain pan disposed adjacent to the air guide member and facing a lower end of the heat exchanger when the indoor unit is embedded in a ceiling, whereinthe drain pan has a bottom disposed lower than an upper end of the passage when the indoor unit is embedded in the ceiling.

4. The indoor unit according to claim 1, further comprising a sealing material sealing a gap between the passage and the refrigerant sensor.

5. The indoor unit according to claim 1, further comprising a filter at the suction port.

6. An air conditioner comprising the indoor unit according to claim 1.

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