Indoor unit and air conditioner

Abstract

One aspect of an indoor unit according to the present disclosure comprises a refrigerant sensor unit having a refrigerant sensor that detects a vaporized refrigerant and a housing that accommodates the refrigerant sensor. The housing comprises a first refrigerant inflow port that guides a vaporized refrigerant to an accommodation space in which the refrigerant sensor is accommodated, and a recess that is provided on an inner surface surrounding the accommodation space and on the side opposite from the refrigerant sensor.

Description

Indoor units and air conditioners

[0001] The present disclosure relates to an indoor unit and an air conditioner.

[0002] Conventionally, air conditioners with a refrigerant sensor attached to the indoor unit have been known. Patent Document 1 discloses an indoor unit in which a drain pan is placed below a heat exchanger and a refrigerant sensor is placed above the drain pan, thereby detecting refrigerant gas leaking from the heat exchanger with the refrigerant sensor.

[0003] Japanese Patent Application Laid-Open No. 2002-98346

[0004] The refrigerant sensor is housed in a housing to protect it from condensation, etc. Such a housing is provided with an inlet for introducing refrigerant gas into the internal storage space. In conventional indoor units, the refrigerant sensor has difficulty detecting refrigerant gas flowing into the housing from the refrigerant inlet until the refrigerant gas fills the interior of the housing, resulting in poor responsiveness.

[0005] In view of the above circumstances, one object of the present disclosure is to provide an indoor unit and an air conditioner that can improve the responsiveness of refrigerant detection.

[0006] One aspect of the indoor unit according to the present disclosure includes a refrigerant sensor unit having a refrigerant sensor that detects vaporized refrigerant and a housing that houses the refrigerant sensor, the housing having a first refrigerant inlet that directs the vaporized refrigerant into an accommodating space that houses the refrigerant sensor, and a recess provided on an inner surface surrounding the accommodating space that faces the refrigerant sensor.

[0007] One aspect of an air conditioner according to the present disclosure includes the above-described indoor unit, the refrigerant circuit, and an outdoor unit.

[0008] According to the present disclosure, it is possible to provide an indoor unit and an air conditioner that can improve the responsiveness of refrigerant detection.

[0009] FIG. 1 is a schematic diagram showing a general configuration of an air conditioner according to an embodiment. FIG. 2 is a perspective view of an indoor unit according to an embodiment. FIG. 3 is a cross-sectional view of the indoor unit according to an embodiment. FIG. 4 is a cross-sectional view of the indoor unit taken along line IV-IV in FIG. 3. FIG. 5 is a cross-sectional view of the indoor unit taken along line V-V in FIG. 3. FIG. 6 is a perspective view of a refrigerant sensor unit according to an embodiment. FIG. 7 is a cross-sectional view of the refrigerant sensor unit according to an embodiment, showing the flow of refrigerant gas. FIG. 8 is a cross-sectional view of the refrigerant sensor unit according to an embodiment, showing the flow of condensation water with arrows. FIG. 9 is a perspective view of a refrigerant sensor according to an embodiment. FIG. 10 is a cross-sectional view of the refrigerant sensor unit according to a first modified example. FIG. 11 is a cross-sectional view of the refrigerant sensor unit according to a second modified example. FIG. 12 is an exploded perspective view of the refrigerant sensor unit according to a second modified example.

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the scope of the present disclosure is not limited to the following embodiments and can be modified as desired within the scope of the technical concept of the present disclosure. In addition, in the following drawings, the scale and number of each structure may differ from the scale and number of the actual structure in order to make each configuration easier to understand.

[0011] The drawings also show the X-axis, Y-axis, and Z-axis as appropriate. The X-axis and Y-axis each represent one of the horizontal directions. The Z-axis represents the up-down direction. In the following description, the horizontal direction along the X-axis is referred to as the "front-rear direction X," the horizontal direction along the Y-axis is referred to as the "left-right direction Y," and the up-down direction along the Z-axis is referred to as the "up-down direction Z." The front-rear direction X, left-right direction Y, and up-down direction Z are perpendicular to each other. In the following description, the side of the front-rear direction X toward which the X-axis arrow points (+X) is referred to as the front side, and the side of the front-rear direction X opposite to the side toward which the X-axis arrow points (-X) is referred to as the rear side. In addition, the side of the left-right direction toward which the Y-axis arrow points (+Y) is referred to as the right side, and the side of the left-right direction Y opposite to the side toward which the Y-axis arrow points (-Y) is referred to as the left side. Furthermore, the side of the vertical direction Z toward which the arrow of the Z axis points (+Z side) is defined as the upper side, and the opposite side of the vertical direction Z to the side toward which the arrow of the Z axis points (-Z side) is defined as the lower side. Note that the left-right direction Y, the front-rear direction X, and the up-down direction Z are names simply used to describe the relative positional relationships of the various parts, and the actual positional relationships may be other than those indicated by these names. In the following embodiments, the front-rear direction X corresponds to the "first direction," and the up-down direction Z corresponds to the "second direction."

[0012] <Air Conditioner> Fig. 1 is a schematic diagram showing the general configuration of an air conditioner 100 according to the present embodiment. As shown in Fig. 1, the air conditioner 100 includes an indoor unit 10, an outdoor unit 20, and a refrigerant circuit 30. The indoor unit 10 is disposed indoors. The outdoor unit 20 is disposed outdoors. The indoor unit 10 and the outdoor unit 20 are connected to each other by the refrigerant circuit 30, through which a refrigerant 33 circulates. The indoor unit 10 and the outdoor unit 20 are heat exchange units that exchange heat with the air.

[0013] The air conditioner 100 can adjust the temperature of the indoor air by exchanging heat between the refrigerant 33 flowing through the refrigerant circuit 30 and the air in the room where the indoor unit 10 is located. Examples of the refrigerant 33 include fluorine-based refrigerants or hydrocarbon-based refrigerants with low global warming potential (GWP). Examples of the refrigerant 33 include a single refrigerant selected from R1234yf, R1234ze, R32, and R290, a mixture of two or more of these refrigerants, or a mixture of any of these refrigerants with another refrigerant. Examples of the refrigerant 33 include a mixture of R1132(E) and R1123. Examples of the refrigerant 33 include a mixed refrigerant of R516A, R445A, R444A, R454C, R444B, R454A, R455A, R457A, R459B, R452B, R454B, R447B, R447A, R446A, and R459A.

[0014] The outdoor unit 20 has a compressor 21, an outdoor heat exchanger 23, a flow rate adjustment valve 24, an outdoor unit blower 25, and a four-way valve 22. The compressor 21, the outdoor heat exchanger 23, the flow rate adjustment valve 24, and the four-way valve 22 are connected by a refrigerant circuit 30.

[0015] The four-way valve 22 is disposed in a portion of the refrigerant circuit 30 that is connected to the discharge side of the compressor 21. The four-way valve 22 switches a portion of the paths in the refrigerant circuit 30, thereby reversing the direction of the refrigerant 33 flowing through the refrigerant circuit 30. When the paths connected by the four-way valve 22 are the paths shown by solid lines in the four-way valve 22 in Fig. 1, the refrigerant 33 flows through the refrigerant circuit 30 in the direction shown by the solid arrows in Fig. 1. On the other hand, when the paths connected by the four-way valve 22 are the paths shown by dashed lines in the four-way valve 22 in Fig. 1, the refrigerant 33 flows through the refrigerant circuit 30 in the direction shown by the dashed arrows in Fig. 1.

[0016] The indoor unit 10 has a blower 15 and a heat exchanger 14 arranged around the blower 15. The indoor unit 10 is capable of cooling operation to cool the air in the room where the indoor unit 10 is arranged, and heating operation to warm the air in the room where the indoor unit 10 is arranged.

[0017] When the indoor unit 10 is in cooling operation, the refrigerant 33 flowing in the refrigerant circuit 30 flows in the direction shown by the solid arrow in Fig. 1. In other words, when the indoor unit 10 is in cooling operation, the refrigerant 33 flowing in the refrigerant circuit 30 circulates through the compressor 21, the outdoor heat exchanger 23 of the outdoor unit 20, the flow control valve 24, and the heat exchanger 14 of the indoor unit 10, in that order, before returning to the compressor 21. During cooling operation, the outdoor heat exchanger 23 in the outdoor unit 20 functions as a condenser, and the heat exchanger 14 in the indoor unit 10 functions as an evaporator.

[0018] On the other hand, when the indoor unit 10 is in heating operation, the refrigerant 33 flowing in the refrigerant circuit 30 flows in the direction shown by the dashed line in Fig. 1. In other words, when the indoor unit 10 is in heating operation, the refrigerant 33 flowing in the refrigerant circuit 30 circulates through the compressor 21, the heat exchanger 14 of the indoor unit 10, the flow control valve 24, and the outdoor heat exchanger 23 of the outdoor unit 20 in that order, before returning to the compressor 21. In heating operation, the outdoor heat exchanger 23 in the outdoor unit 20 functions as an evaporator, and the heat exchanger 14 in the indoor unit 10 functions as a condenser.

[0019] <Indoor unit> Next, the indoor unit 10 of this embodiment will be described in further detail. Fig. 2 is a perspective view of the indoor unit 10 of this embodiment. Fig. 3 is a cross-sectional view of the indoor unit 10, showing the indoor unit 10 as seen from the front. Fig. 4 is a cross-sectional view of the indoor unit 10 taken along line IV-IV in Fig. 3. Fig. 5 is a cross-sectional view of the indoor unit 10 taken along line V-V in Fig. 3.

[0020] As shown in Fig. 2, indoor unit 10 of this embodiment is a wall-mounted indoor unit that is fixed to the upper region of a room's wall. As shown in Fig. 3, indoor unit 10 of this embodiment includes, in addition to housing 11, heat exchanger 14, and blower 15 described above, a drain pan 40, a control unit 50, and a refrigerant sensor unit 60. Housing 11 houses heat exchanger 14, blower 15, drain pan 40, control unit 50, and refrigerant sensor unit 60.

[0021] <Housing> As shown in FIG. 2 , the housing 11 of this embodiment is a substantially rectangular box-like shape that is elongated in the left-right direction Y. The housing 11 has a top panel 11a, a front panel 11b, a bottom panel 11c, a first side panel (side panel) 11d, a second side panel 11e, and a back panel 11f. The top panel 11a covers the internal space of the housing 11 from above. The front panel 11b covers the internal space of the housing 11 from the front side (+X). The bottom panel 11c covers the internal space of the housing 11 from below. The first side panel 11d covers the internal space of the housing 11 from the right side (+Y). The second side panel 11e covers the internal space of the housing 11 from the left side (-Y). The back panel 11f covers the internal space of the housing 11 from the rear side (-X).

[0022] As shown in FIG. 4 , the housing 11 is provided with an air inlet 12 and an air outlet 13. The air inlet 12 is provided on the top panel 11a. The air inlet 12 opens on the upper side and extends in the left-right direction Y. A filter 12a that removes dust from the air that is drawn in is disposed in the air inlet 12. The air outlet 13 is provided on the front end of the bottom panel 11c and the lower end of the front panel 11b. The air outlet 13 opens on the front side (+X) and lower side and extends in the left-right direction Y. The air outlet 13 is provided with an air direction vane 13a that adjusts the direction of the air that is blown out. When the indoor unit 10 is stopped, the air outlet 13 is covered by the air direction vane 13a.

[0023] <Blower> As shown in Fig. 3, the blower 15 of this embodiment is a crossflow fan. The blower 15 has an impeller 15a extending in the left-right direction Y and a drive motor 15b disposed on the right (+Y) side of the impeller 15a. The impeller 15a is generally cylindrical and has a plurality of blades (not shown) arranged in the circumferential direction. The impeller 15a and the drive motor 15b rotate the impeller 15a around a rotation axis extending in the left-right direction Y.

[0024] <Heat Exchanger> The heat exchanger 14 includes a heat exchanger body 14d and a pipe connecting portion 14e. The heat exchanger body 14d includes multiple fin members extending along a plane perpendicular to the left-right direction Y and aligned in the left-right direction Y, and multiple pipes penetrating the multiple fin members. The pipe connecting portion 14e is located at the right (+Y) end of the heat exchanger body 14d. The pipe connecting portion 14e is connected to the pipes of the heat exchanger body 14d. The pipe connecting portion 14e includes multiple hairpin-shaped pipes connecting the multiple pipes of the heat exchanger body 14d to each other and pipes connecting the pipes of the heat exchanger body 14d to external pipes. The pipes of the heat exchanger 14 form part of the refrigerant circuit 30 (see FIG. 1), and a refrigerant flows through the heat exchanger body 14d. The heat exchanger body 14d exchanges heat between the air in the housing 11 and the refrigerant. As a result, the heat exchanger 14 cools or heats the air drawn into the blower 15 .

[0025] As shown in FIG. 4 , the heat exchanger 14 has a first portion 14a, a second portion 14b, and a third portion 14c. The first portion 14a is located in front of the impeller 15a (+X). When viewed from the left-right direction Y, the first portion 14a extends in the up-down direction Z. The second portion 14b and the third portion 14c are located above the impeller 15a. When viewed from the left-right direction Y, the second portion 14b extends upward (+Z) and diagonally rearward (-X) from the upper end of the first portion 14a. The third portion 14c is located behind the second portion 14b (-X). When viewed from the left-right direction Y, the third portion 14c extends downward (-Z) and diagonally rearward (-X) from the upper end of the second portion 14b.

[0026] <Drain Pan> As shown in Fig. 3, the drain pan 40 is disposed in the lower portion of the internal space of the housing 11. The drain pan 40 extends in the left-right direction Y. The drain pan 40 has a drain pan main body 41 and a drain pan side end portion 42. As shown in Fig. 4, the drain pan main body 41 is located directly below the first portion 14a of the heat exchanger main body 14d. As shown in Fig. 5, the drain pan side end portion 42 is located directly below the pipe connecting portion 14e. The drain pan side end portion 42 is connected to the right (+Y) end portion of the drain pan main body 41.

[0027] 4, the drain pan body 41 has a reservoir 41p that opens upward. The drain pan body 41 extends in a gutter-like shape in the left-right direction Y. The drain pan body 41 receives, from below, in the reservoir 41p, condensed water that condenses and drips from the surface of the heat exchanger body 14d.

[0028] As shown in FIG. 5 , the drain pan end 42 has a reservoir 42p that opens upward. The drain pan end 42 receives condensed water that condenses and drips from the surface of the pipe connecting portion 14e in the reservoir 42p from below. The reservoir 42p of the drain pan end 42 is connected to the reservoir 41p of the drain pan main body 41. Therefore, not only condensed water that drips from the pipe connecting portion 14e but also condensed water received by the drain pan main body 41 flows into the reservoir 42p of the drain pan end 42. A drain hose 49 is connected to the drain pan end 42. The condensed water received by the drain pan 40 is discharged to the outdoors via the drain hose 49. A water-absorbing sheet (not shown) is provided on the upper surface of the bottom panel 11c of the housing 11. The water-absorbing sheet receives and absorbs condensation water dripping from the surface of the drain hose 49 and from the connection between the drain pan side end 42 and the drain hose 49. In this way, the water-absorbing sheet prevents condensation water from dripping downward from the indoor unit 10.

[0029] The underside of the drain pan end 42 is covered with a heat insulating material 48. This prevents condensation from forming on the underside of the drain pan end 42. The refrigerant sensor unit 60 is disposed below the drain pan end 42. According to this embodiment, condensation is less likely to adhere to the underside of the drain pan end 42, preventing condensation from dripping from the drain pan end 42 onto the refrigerant sensor unit 60. This prevents condensation from affecting the operation of the refrigerant sensor unit 60.

[0030] Furthermore, in this embodiment, refrigerant sensor unit 60 is located directly below drain pan end 42. That is, refrigerant sensor unit 60 is positioned offset in the left-right direction Y with respect to impeller 15a of blower 15. Therefore, even if the rotation of impeller 15a causes condensation water to splash from impeller 15a or from surrounding components that receive the wind from impeller 15a, it is possible to prevent this condensation water from splashing onto refrigerant sensor unit 60.

[0031] 3, the control unit 50 is located to the right (+Y) of the heat exchanger 14 and the blower 15. The control unit 50 controls the components necessary for the heating and cooling operation of the air conditioner 100. The control unit 50 controls the blower 15, the heat exchanger 14, etc. based on the measurement results of the refrigerant sensor unit 60 and various sensors provided in the heat exchanger 14.

[0032] <Refrigerant Sensor Unit> As shown in FIG. 5 , the refrigerant sensor unit 60 is disposed below the drain pan 40. The drain pan 40 is also located below the heat exchanger 14. Generally, refrigerant gas is heavier than air. Therefore, refrigerant that leaks from the heat exchanger 14 and vaporizes (hereinafter referred to as refrigerant gas) accumulates in the reservoirs 41p and 42p of the drain pan 40. The refrigerant gas that accumulates in the reservoirs 41p and 42p of the drain pan 40 flows over the front (+X) and rear (-X) walls of the drain pan 40 toward the bottom of the drain pan 40. The refrigerant sensor unit 60 detects refrigerant gas flowing into the refrigerant sensor unit 60 from the front (+X) or rear (-X) side below the drain pan 40 and transmits the detection result to the control unit 50.

[0033] Figures 6 and 7 are perspective views of the refrigerant sensor unit as viewed from different directions. Figures 8 and 9 are cross-sectional views of the refrigerant sensor unit 60. In Figure 8, the flow of refrigerant gas is indicated by arrows. In Figure 9, the flow of condensed water adhering to the refrigerant sensor unit 60 is indicated by arrows.

[0034] As shown in FIG. 8 , the refrigerant sensor unit 60 includes a refrigerant sensor 70, a housing 80, and other functional units 68 and 69. The refrigerant sensor unit 60 of this embodiment has not only the function of detecting refrigerant gas, but also other functions. Examples of the other functions include a monitoring function for monitoring the living space in which the indoor unit 10 is located, and an antenna function for receiving radio waves from a remote controller. The other functional units 68 and 69 perform these other functions. A detailed description of the other functional units 68 and 69 will be omitted.

[0035] The housing 80 has a base member 81 and a lid member 82. The housing 80 also has an accommodation space A in which the refrigerant sensor 70 and the other functional units 68, 69 are disposed. The base member 81 and the lid member 82 surround the accommodation space A. The base member 81 supports the refrigerant sensor 70 and the other functional units 68, 69. The lid member 82 is positioned above the base member 81 and is fixed to the base member 81. The lid member 82 covers the refrigerant sensor and the other functional units 68, 69 from above. In this way, the lid member 82 protects the refrigerant sensor and the other functional units 68, 69.

[0036] The base member 81 has a base plate portion 81p, a first wall portion 81a, a second wall portion 81b, and a third wall portion 81c. The base plate portion 81p extends along a horizontal plane (XY plane). The first wall portion 81a, the second wall portion 81b, and the third wall portion 81c protrude upward from the base plate portion 81p. The first wall portion 81a, the second wall portion 81b, and the third wall portion 81c are each plate-shaped and extend along a plane perpendicular to the front-rear direction X. The first wall portion 81a, the second wall portion 81b, and the third wall portion 81c are arranged in this order from the front side (+X) to the rear side (-X).

[0037] A first other functional unit 68 is disposed in front (+X) of the first wall 81a. A second other functional unit 69 is disposed between the first wall 81a and the second wall 81b. A refrigerant sensor 70 is disposed between the second wall 81b and the third wall 81c.

[0038] A first groove 81d is provided in the second wall portion 81b. The first groove 81d opens to the rear (-X) side and extends in the left-right direction Y. Similarly, a second groove 81e is provided in the third wall portion 81c. The second groove 81e opens to the front (+X) side and extends in the left-right direction Y. The openings of the first groove 81d and the second groove 81e face each other in the front-to-rear direction X. The groove widths of the first groove 81d and the second groove 81e are slightly larger than the thickness of a sensor substrate 73 of the refrigerant sensor 70 (described later). The sensor substrate 73 is inserted into the first groove 81d and the second groove 81e. This allows the base plate portion 81p to support the refrigerant sensor 70. Although not shown, the other functional units 68 and 69 are each fixed to the base plate portion 81p by fixing means such as fixing screws.

[0039] As shown in Figures 6 and 7, the cover member 82 has a first upper plate portion 82a, a second upper plate portion 82b, a step portion 82g, a convex portion 84, a front plate portion 82c, a rear plate portion 82d, a side plate portion 82e, and a side case portion 83.

[0040] The first upper plate portion 82a and the second upper plate portion 82b extend along a horizontal plane (XY plane). The first upper plate portion 82a is located higher than the second upper plate portion 82b. The first upper plate portion 82a is located rearward (-X) than the second upper plate portion 82b. A step portion 82g is provided between the first upper plate portion 82a and the second upper plate portion 82b. The step portion 82g extends linearly in the left-right direction Y.

[0041] The front plate portion 82c and the rear plate portion 82d extend along a plane perpendicular to the front-rear direction X. The front plate portion 82c and the rear plate portion 82d are disposed opposite each other in the front-rear direction X.

[0042] As shown in FIG. 6 , the front plate 82c is connected to the front end of the second upper plate 82b. A first refrigerant inlet 85 is provided through the front plate 82c in the front-rear direction X. That is, the housing 80 has the first refrigerant inlet 85. The first refrigerant inlet 85 connects the storage space A of the housing 80 to the space outside the housing 80. The first refrigerant inlet 85 opens the storage space A to the front side (+X). The first refrigerant inlet 85 guides refrigerant gas from the front side (+X) into the storage space A that houses the refrigerant sensor 70.

[0043] As shown in FIG. 7 , the rear plate 82d is connected to the rear end of the first upper plate 82a. A second refrigerant inlet 86 is provided in the rear plate 82d, penetrating the rear plate 82d in the front-rear direction X. That is, the housing 80 has the second refrigerant inlet 86. The second refrigerant inlet 86 connects the storage space A of the housing 80 with the space outside the housing 80. The second refrigerant inlet 86 opens the storage space A to the rear side (−X). The second refrigerant inlet 86 guides refrigerant gas from the rear side into the storage space A that houses the refrigerant sensor 70.

[0044] The side plate portion 82e extends along a plane perpendicular to the left-right direction Y. The side plate portion 82e is connected to the left (-Y) ends of the first upper plate portion 82a, the second upper plate portion 82b, the front plate portion 82c, and the rear plate portion 82d. The side case portion 83 is connected to the right (+Y) ends of the first upper plate portion 82a, the second upper plate portion 82b, the front plate portion 82c, and the rear plate portion 82d. The side case portion 83 houses other functional portions (not shown).

[0045] As shown in FIG. 8 , the protrusion 84 is located at the front (+X) end of the first upper plate 82a. The protrusion 84 protrudes upward from the upper surface of the first upper plate 82a. The cover member 82 is plate-shaped. Therefore, the lower surface of the protrusion 84 is recessed upward. Here, the surface of the housing 80 that faces the storage space A and surrounds the storage space A is referred to as the inner surface 80f of the housing 80. The lower surface of the first upper plate 82a forms part of the inner surface 80f of the housing 80. The inner surface 80f of the housing 80 has a recess 88 located inside the protrusion 84. In other words, the housing 80 has the recess 88. The recess 88 expands the storage space A upward.

[0046] The recess 88 opens downward. The recess 88 has an upper wall surface 88a and a side wall surface 88b. The upper wall surface 88a is a surface that extends along the horizontal plane (XY plane) and faces downward. The upper wall surface 88a is located above the upper surface of the first upper plate portion 82a. The side wall surface 88b is connected to the upper wall surface 88a and extends downward from the upper wall surface 88a. The side wall surface 88b is a surface that faces horizontally. In this embodiment, the side wall surface 88b surrounds the internal space of the recess 88 in a frame-like manner from the horizontal direction.

[0047] A third refrigerant inlet 87 is provided in a portion of the side wall surface 88b of the recess 88 facing the front side (+X). That is, the housing 80 has the third refrigerant inlet 87 that opens to the side wall surface 88b. The third refrigerant inlet 87 connects the storage space A of the housing 80 with the external space of the housing 80. The third refrigerant inlet 87 opens the storage space A (more specifically, the space inside the recess 88) to the rear side (-X). The third refrigerant inlet 87 introduces refrigerant gas into the storage space A of the housing 80.

[0048] An inclined surface 88t is provided on a portion of the side wall surface 88b of the recess 88 facing the rear (-X) side. The inclined surface 88t slopes downward as it approaches the front (+X) side. The inclined surface 88t smoothly connects to the inner surface of the stepped portion 82g. The inclined surface 88t smooths the flow of refrigerant gas that passes under the second upper plate portion 82b and flows into the recess 88.

[0049] 10 is a perspective view of the refrigerant sensor 70. The refrigerant sensor 70 has a sensor substrate (substrate) 73, a sensor element 71, and an element case 72.

[0050] The sensor substrate 73 extends along a horizontal plane (XY plane). The sensor substrate 73 has a mounting surface 73a on which the sensor element 71 and other elements 78 are mounted. In this embodiment, the mounting surface 73a faces upward (+Z).

[0051] The sensor element 71 detects vaporized refrigerant gas. The sensor element 71 is mounted on a mounting surface 73a of a sensor substrate 73. The sensor element 71 is surrounded by an element case 72. Thus, the sensor element 71 is protected by the element case 72.

[0052] The element case 72 has a cylindrical shape extending upward (+Z) from the mounting surface 73a. The element case 72 has a base end 72a fixed to the mounting surface 73a and a tip end 72b opposite the base end 72a. The base end 72a of the element case 72 is fixed tightly to the mounting surface 73a with an adhesive or the like. A case opening 72h is provided at the tip end 72b of the element case 72 to introduce refrigerant gas into the interior of the element case 72. The case opening 72h opens upward. The sensor element 71 detects refrigerant gas flowing into the interior of the element case 72 through the case opening 72h.

[0053] 8 , in the housing 80 of this embodiment, the first refrigerant inlet 85 and the second refrigerant inlet 86 are located on the front (+X) and rear (−X) sides, respectively, of the refrigerant sensor 70. As described above, refrigerant gas accumulated in the drain pan 40 flows downward over the front and rear walls of the drain pan 40 and flows toward the front or rear below the drain pan 40. According to this embodiment, the first refrigerant inlet 85 guides refrigerant gas flowing toward the rear below the drain pan 40 into the storage space A. Similarly, the second refrigerant inlet 86 guides refrigerant gas flowing toward the front below the drain pan 40 into the storage space A.

[0054] Furthermore, as the blower 15 is driven, an air flow is formed around the refrigerant sensor unit 60 in the front-rear direction X. According to the present embodiment, the first refrigerant inlet 85 and the second refrigerant inlet 86 are arranged side by side in the front-rear direction X. Furthermore, the refrigerant sensor 70 is arranged between the first refrigerant inlet 85 and the second refrigerant inlet 86 in the front-rear direction X. According to the present embodiment, the refrigerant sensor 70 is arranged midway along the path through the storage space A from the first refrigerant inlet 85 to the second refrigerant inlet 86, or along the path through the storage space A from the second refrigerant inlet 86 to the first refrigerant inlet 85. According to the present embodiment, the refrigerant gas entrained in the air flow generated by the blower 15 can be guided to the refrigerant sensor 70 inside the storage space A.

[0055] In the storage space A of this embodiment, gaps are provided between the underside of the lid member 82 and the first and second wall portions 81a and 81b of the base member 81 and the other functional portions 68 and 69 fixed to the base member 81. Refrigerant gas flowing into the storage space A from the first refrigerant inlet 85 flows rearward (−X) along the underside of the lid member 82. When the refrigerant gas reaches the lower side of the recess 88, some of the refrigerant gas changes its flow direction upward and enters the interior of the recess 88. Similarly, in the storage space A, a gap is provided between the underside of the lid member 82 and the third wall portion 81c of the base member 81. When the refrigerant gas flows into the storage space A from the second refrigerant inlet 86, it flows frontward (+X) along the underside of the lid member 82. When the refrigerant gas reaches the lower side of the recess 88, some of the refrigerant gas changes its flow direction upward and enters the interior of the recess 88. The refrigerant gas that is introduced into the storage space A through the first refrigerant inlet 85 or the second refrigerant inlet 86 and then flows into the recess 88 swirls along the side wall surface 88b and the upper wall surface 88a of the recess 88. As a result, the flow velocity of the refrigerant gas decreases and eventually flows out of the recess 88 to the lower side.

[0056] In this embodiment, the recess 88 of the housing 80 faces the refrigerant sensor 70. Therefore, the refrigerant gas that flows out of the recess 88 after being retained in the recess 88 is naturally guided to the refrigerant sensor 70. The refrigerant gas flowing out of the recess 88 has a reduced flow velocity within the recess 88, making it easier for the refrigerant sensor 70 to detect it. According to this embodiment, the refrigerant sensor 70 can immediately detect the refrigerant gas, thereby improving the responsiveness of the refrigerant sensor unit 60 in detecting the refrigerant gas.

[0057] In this embodiment, the direction connecting the first refrigerant inlet 85 and the refrigerant sensor 70 is the front-rear direction X. The recess 88 is recessed in the up-down direction Z, which is perpendicular to the direction connecting the first refrigerant inlet 85 and the refrigerant sensor 70 (the front-rear direction X). According to this embodiment, refrigerant gas flowing in the accommodation space A from the first refrigerant inlet 85 toward the refrigerant sensor 70 in the front-rear direction X changes its flow direction to the up-down direction Z when it flows into the recess 88. As a result, the refrigerant gas swirls within the recess 88, reducing its flow velocity before being guided to the refrigerant sensor 70. According to this embodiment, the recess 88 can reduce the flow velocity of the refrigerant gas. As a result, the refrigerant gas is more likely to remain around the refrigerant sensor 70, making it easier for the refrigerant sensor 70 to immediately detect the refrigerant gas.

[0058] The same effect applies to the refrigerant gas flowing into the storage space A through the second refrigerant inlet 86. That is, in this embodiment, the recessed direction (vertical direction Z) of the recess 88 is perpendicular to the direction (front-rear direction X) connecting the second refrigerant inlet 86 and the refrigerant sensor 70. According to this embodiment, the refrigerant gas flowing into the storage space A through the second refrigerant inlet 86 and further into the recess 88 can be swirled within the recess 88 to reduce its flow rate. As a result, the refrigerant gas is more likely to be trapped around the refrigerant sensor 70, making it easier for the refrigerant sensor 70 to immediately detect the refrigerant gas.

[0059] In particular, in this embodiment, the sensor element 71 of the refrigerant sensor 70 is enclosed in the element case 72. Enclosing the sensor element 71 in the element case 72 protects the sensor element 71 while also making it more difficult for refrigerant gas to reach the sensor element 71. According to this embodiment, the case opening 72h faces the recess 88 in the up-down direction Z, which is the direction in which the recess 88 is recessed. Therefore, the flow velocity of the refrigerant gas flowing out of the recess 88 can be reduced by the recess 88, and the refrigerant gas can be guided into the interior of the element case 72 through the case opening 72h.

[0060] Furthermore, the recess 88 of this embodiment is recessed upward and opens downward. Furthermore, the case opening 72h of the element case 72 of this embodiment opens upward below the recess 88. According to this embodiment, the fluid whose flow velocity is reduced in the recess 88 and which flows downward due to gravity can be guided into the element case 72.

[0061] As described above, the recess 88 has an opening for the third refrigerant inlet 87. The third refrigerant inlet 87 guides the refrigerant gas flowing along the upper surface of the housing 80 into the storage space A. According to this embodiment, the refrigerant sensor unit 60 can more easily detect a wider range of refrigerant gas in the surrounding area, thereby improving the responsiveness of the refrigerant sensor unit 60.

[0062] In this embodiment, the third refrigerant inlet 87 opens into the recess 88. Therefore, the refrigerant gas flowing into the accommodation space A from the third refrigerant inlet 87 is smoothly guided to the refrigerant sensor 70 facing the recess 88 and is immediately detected.

[0063] In this embodiment, the third refrigerant inlet 87 opens to a side wall surface 88b of the recess 88. The side wall surface 88b faces horizontally. According to this embodiment, the third refrigerant inlet 87 is less likely to allow condensed water to enter the storage space A than when the refrigerant inlet opens to the top wall surface 88a.

[0064] As shown in FIG. 9 , the first upper plate 82a extends in a direction inclined relative to the horizontal plane Hp. Therefore, the upper surface of the first upper plate 82a is inclined downward toward the rear (-X) side. Here, the upper surface of the first upper plate 82a on the upper surface of the housing 80 is referred to as the inclined region 82t. The inclined region 82t connects to the lower end of the third refrigerant inlet 87 at its front (+X) end. According to this embodiment, condensed water adhering to the inclined region 82t can be caused to flow by gravity in a direction away from the third refrigerant inlet 87. This prevents condensed water from entering the storage space A.

[0065] The inclination angle α of the inclined region 82t with respect to the horizontal plane Hp is preferably 1° or greater and 10° or less. Setting the inclination angle α to 1° or greater can prevent condensation water from flowing toward the third refrigerant inlet 87. Setting the inclination angle α to 10° or less can make it easier to compact the arrangement space for the refrigerant sensor unit 60 inside the casing 11 and ensure a sufficiently wide storage space A for the housing 80.

[0066] (Summary) As shown in FIG. 1 , the indoor unit 10 of this embodiment is an indoor unit 10 of an air conditioner 100 having a refrigerant circuit through which a refrigerant circulates. As shown in FIG. 5 , the indoor unit 10 has a refrigerant sensor unit 60. As shown in FIG. 8 , the refrigerant sensor unit 60 has a refrigerant sensor 70 that detects vaporized refrigerant and a housing 80 that houses the refrigerant sensor 70. The housing 80 has a first refrigerant inlet 85 and a recess 88. The first refrigerant inlet 85 guides vaporized refrigerant into the storage space A that houses the refrigerant sensor 70. The recess 88 is provided on an inner surface 80f that surrounds the storage space A. The recess 88 faces the refrigerant sensor 70. With this configuration, the refrigerant gas in the storage space A flows into the recess 88, reducing the flow rate of the refrigerant gas, allowing the refrigerant sensor 70 to detect the refrigerant gas. This allows the refrigerant sensor 70 to detect the refrigerant gas without filling the storage space A with the refrigerant gas, thereby improving the responsiveness of the refrigerant sensor unit 60 in detecting the refrigerant gas.

[0067] In this embodiment, the direction connecting the first refrigerant inlet 85 and the refrigerant sensor 70 (the front-rear direction X in this embodiment) is defined as the first direction. The direction perpendicular to the first direction (the front-rear direction X) (the up-down direction Z in this embodiment) is defined as the second direction. The recess 88 is recessed in the second direction (the up-down direction Z) facing the refrigerant sensor 70 in the second direction (the up-down direction Z). With this configuration, refrigerant gas flowing in the accommodation space A from the first refrigerant inlet 85 toward the refrigerant sensor 70 in the first direction (the front-rear direction X) changes its flow direction to the second direction (the up-down direction Z) before flowing into the recess 88. This allows the refrigerant gas to swirl within the recess 88, thereby reducing its flow velocity. As a result, the refrigerant gas with a reduced flow velocity can be guided to the refrigerant sensor 70, preventing the refrigerant gas from flowing around the refrigerant sensor 70 without being detected by the refrigerant sensor 70. This improves the refrigerant gas detection responsiveness of the refrigerant sensor unit 60.

[0068] In this embodiment, the housing 80 has a second refrigerant inlet 86. The second refrigerant inlet 86 guides vaporized refrigerant to the storage space A that houses the refrigerant sensor 70. The first refrigerant inlet 85 and the second refrigerant inlet 86 are located on one side (front) and the other side (rear) of the refrigerant sensor 70 in the first direction (front-rear direction X). When the blower 15 of the indoor unit 10 is driven, a gentle airflow is generated around the refrigerant sensor unit 60, which is located inside the housing 11 and outside the air passage. With the above-described configuration, refrigerant gas can be guided into the storage space A of the housing 80 regardless of whether the airflow around the refrigerant sensor unit 60 flows in one direction or the other direction in the front-rear direction X. Furthermore, with the above-described configuration, the first refrigerant inlet 85 and the second refrigerant inlet 86 are aligned in the front-rear direction X. The refrigerant sensor 70 is located between the first refrigerant inlet 85 and the second refrigerant inlet 86 in the front-rear direction X. Therefore, the refrigerant sensor 70 can be disposed midway along the path through the storage space A that runs from the first refrigerant inlet 85 to the second refrigerant inlet 86, or along the path that runs from the second refrigerant inlet 86 to the first refrigerant inlet 85. This makes it easier for the refrigerant gas that rides on the air flow generated by the blower 15 to be guided to the refrigerant sensor 70 inside the storage space A, thereby improving the responsiveness of refrigerant gas detection.

[0069] In this embodiment, the refrigerant sensor 70 includes a sensor substrate 73, a sensor element 71, and a cylindrical element case 72. The sensor substrate 73 has a mounting surface 73a. The sensor element 71 is mounted on the mounting surface 73a. The element case 72 is fixed to the mounting surface 73a, surrounds the sensor element 71, and extends perpendicularly from the mounting surface. A case opening 72h is provided at the end of the element case 72 opposite the mounting surface 73a, through which vaporized refrigerant is guided into the element case 72. The case opening 72h faces the recess 88 in the second direction (the vertical direction Z). This configuration allows the element case 72 to protect the sensor element 71 from moisture, dust, and the like. Furthermore, the flow rate is reduced within the recess 88, allowing refrigerant gas flowing out of the recess 88 to be guided into the element case 72 through the case opening 72h. This allows the sensor element 71 in the element case 72 to immediately detect refrigerant gas.

[0070] In this embodiment, the recess 88 is recessed upward. The case opening 72h opens upward below the recess 88. With this configuration, the fluid that flows downward due to gravity, having its flow rate reduced in the recess 88, can be easily guided into the element case 72.

[0071] In this embodiment, the recess 88 has a downward-facing upper wall surface 88a and a horizontally facing side wall surface 88b extending downward from the upper wall surface 88a. The housing 80 has a third refrigerant inlet 87 opening in the side wall surface 88b. With this configuration, refrigerant flowing on one side (upper side) of the refrigerant sensor unit 60 in the second direction can be guided into the storage space A through the third refrigerant inlet 87. This makes it easier for the refrigerant sensor 70 to detect refrigerant gas around the refrigerant sensor unit 60, thereby improving the responsiveness of the refrigerant sensor unit 60. Furthermore, with the above-described configuration, because the third refrigerant inlet 87 opens in the side wall surface 88b, it is possible to prevent condensed water from entering the storage space A through the third refrigerant inlet 87.

[0072] In this embodiment, an inclined region 82t is provided on the upper surface of the housing 80, and is continuous with the lower edge of the third refrigerant inlet 87. The inclined region 82t is inclined downward as it increases away from the third refrigerant inlet 87. As shown in Fig. 9 , this configuration prevents condensation water adhering to the inclined region 82t from flowing due to gravity in a direction away from the third refrigerant inlet 87 and from entering the storage space A via the third refrigerant inlet 87.

[0073] 11 is a cross-sectional view of a refrigerant sensor unit 160 according to a first modification that can be used in the above-described embodiment. In the description of this modification, the same components as those in the previously described embodiment are designated by the same reference numerals, and their description will be omitted. The refrigerant sensor unit 160 according to this modification differs from the above-described embodiment mainly in that the housing 180 does not have the third refrigerant inlet 87 (see FIG. 8 ).

[0074] Similar to the above-described embodiment, the refrigerant sensor unit 160 of this modified example includes a refrigerant sensor 70 and a housing 180 that houses the refrigerant sensor 70. The housing 180 also includes a base member 81 that surrounds the storage space A of the housing 180, and a lid member 182. A recess 88 is provided on the underside of the lid member 182. The recess 88 is located above the refrigerant sensor 70.

[0075] In this modified example, no refrigerant inlet is provided on the inner surface of the recess 88. Therefore, refrigerant gas that flows into the storage space A from the first refrigerant inlet 85 or the second refrigerant inlet 86 and then into the interior of the recess 88 is less likely to flow out of the refrigerant sensor unit 160. This allows the refrigerant sensor unit 160 to more reliably detect refrigerant gas that has flowed into the storage space A of the refrigerant sensor unit 160. The configuration of this modified example can improve the responsiveness of refrigerant gas sensor detection compared to the above embodiment when refrigerant gas has difficulty passing above the refrigerant sensor unit 160.

[0076] 12 is a cross-sectional view of a refrigerant sensor unit 260 according to a second modification that can be used in the above-described embodiment. In the description of this modification, the same components as those in the previously described embodiment are designated by the same reference numerals, and their description will be omitted. The refrigerant sensor unit 260 according to this modification differs from the above-described embodiment mainly in that the housing 280 includes a sensor support member 289 that is detachably attached to the base member 281.

[0077] Similar to the above-described embodiment, refrigerant sensor unit 260 of this modified example includes refrigerant sensor 70 and housing 280 that houses refrigerant sensor 70. Refrigerant sensor 70 is disposed in storage space A of housing 280. Housing 280 of this modified example includes a sensor support member 289 in addition to a base member 281 and a cover member 282.

[0078] The base member 281 supports a sensor support member 289. The base member 281 has a first wall portion 281a and a second wall portion 281b that face each other in the front-rear direction X. The first wall portion 281a is located in front of the second wall portion 281b (+X). The sensor support member 289 is disposed in the gap between the first wall portion 281a and the second wall portion 281b. In the following description, the gap between the first wall portion 281a and the second wall portion 281b will be referred to as arrangement space B. The arrangement space B opens downward (-Z).

[0079] The first wall portion 281a is provided with a first step surface 281c facing upward (+Z). The second wall portion 281b is provided with a second step surface 281d facing upward (+Z). In this modified example, the second step surface 281d is located above (+Z) the first step surface 281c. In this modified example, the second wall portion 281b is elastically deformable in a direction in which its upper end moves in the front-rear direction X.

[0080] The lid member 282 is fixed to the upper side of the base member 281. The lid member 282 covers the arrangement space B from above. The underside of the lid member 282 is provided with a recess 288 that is recessed upward. The recess 288 is disposed directly above the arrangement space B. Furthermore, a refrigerant inlet 286 is provided at the rear (-X) end of the lid member 282. That is, the housing 280 has the refrigerant inlet 286. The refrigerant inlet 286 introduces refrigerant gas into the storage space A from the rear (-X) side.

[0081] The sensor support member 289 is box-shaped. The sensor support member 289 has a support space C that surrounds the refrigerant sensor 70. The support space C constitutes a part of the storage space A. The sensor support member 289 has a top plate portion 289a that covers the support space C from above, a bottom plate portion 289b that covers the support space C from below, a front plate portion 289c that covers the support space C from the front side (+X), and a rear plate portion 289d that covers the support space C from the rear side (-X). Although not shown, the sensor support member 289 of this modified example further has side plate portions that cover the support space C from both sides in the left-right direction Y.

[0082] The top plate portion 289a and the bottom plate portion 289b extend along a plane perpendicular to the up-down direction Z and face each other in the up-down direction Z. The bottom plate portion 289b extends along the underside of the sensor board 73. The front plate portion 289c and the rear plate portion 289d extend along a plane perpendicular to the front-rear direction X and face each other in the front-rear direction X. A first groove portion 289e is provided in the front plate portion 289c. The first groove portion 289e opens to the rear side (-X) and extends in the left-right direction Y. Similarly, a second groove portion 289g is provided in the rear plate portion 289d. The second groove portion 289g opens to the front side (+X) and extends in the left-right direction Y. The opening of the first groove portion 289e and the opening of the second groove portion 289g face each other in the front-rear direction X. The groove widths of the first groove 289e and the second groove 289g are slightly larger than the plate thickness of the sensor board 73. The sensor board 73 is inserted into the first groove 289e and the second groove 289g. In this way, the sensor support member 289 supports the refrigerant sensor 70.

[0083] A first rib 289j that protrudes to the front side (+X) and extends in the left-right direction Y is provided at the lower end of the front plate portion 289c. The first rib 289j is mounted on a first stepped surface 281c of the base member 281. A second rib 289k that protrudes to the rear side (-X) and extends in the left-right direction Y is provided at the upper end of the rear plate portion 289d. The second rib 289k is mounted on a second stepped surface 281d of the base member 281. In this way, the sensor support member 289 is supported by the base member 281.

[0084] The top plate portion 289a is located above the sensor board 73. A window portion 289w is provided in the top plate portion 289a. The window portion 289w penetrates the top plate portion 289a in the up-down direction Z. A part of the element case 72 is disposed in the window portion 289w. That is, the tip of the element case 72 is disposed inside the window portion 289w. As in the above-described embodiment, a case opening 72h is provided at the tip of the element case 72 to introduce refrigerant gas into the inside of the element case 72. Therefore, in this modified example, the case opening 72h is disposed outside the sensor support member 289 and within the accommodation space A. Furthermore, the case opening 72h opens upward below the recess 288.

[0085] FIG. 13 is an exploded perspective view of a refrigerant sensor unit 260 of this modified example. In the housing 280 of this modified example, the sensor support member 289 is detachable from the base member 281. The operator first hooks the first rib 289j shown in FIG. 12 onto the first step surface 281c of the base member 281. Next, the operator moves the second rib 289k of the sensor support member 289 upward (+Z). This causes the second wall portion 281b of the base member 281 to elastically deform rearward (-X), moving the second rib 289k above the second step surface 281d of the base member 281. As a result, the sensor support member 289 is mounted on the first step surface 281c and the second step surface 281d of the base member 281, and the sensor support member 289 is supported by the base member 281.

[0086] Similar to the above-described embodiment, housing 280 of this modified example has a refrigerant inlet 286 that guides vaporized refrigerant into storage space A, and a recess 288 that faces refrigerant sensor 70. According to this modified example, by allowing refrigerant gas to flow into recess 288 in storage space A, the flow rate of the refrigerant gas can be reduced, allowing refrigerant sensor 70 to detect the refrigerant gas, and the responsiveness of refrigerant sensor unit 260 in detecting the refrigerant gas can be improved.

[0087] The housing 280 of this modified example also includes a base member 281 and a sensor support member 289 that supports the refrigerant sensor 70 and is detachably attached to the base member 281. According to this modified example, the refrigerant sensor 70 can be removed from the base member 281 together with the sensor support member 289, facilitating maintenance of the refrigerant sensor 70. Furthermore, the necessity for the refrigerant sensor 70 in the air conditioner 100 varies depending on the amount of circulating refrigerant. For example, the refrigerant sensor 70 is not necessarily required when one outdoor unit 20 is connected to one indoor unit 10, but may be required when multiple outdoor units 20 are connected. According to this modified example, the sensor support member 289 that supports the refrigerant sensor 70 can be attached to the base member 281 depending on the necessity for the refrigerant sensor 70. This makes it possible to provide indoor units 10 that are compatible with air conditioners 100 of various configurations.

[0088] An outer panel (not shown) that covers the installation space B from below is attached to the housing 280. When installing the refrigerant sensor 70, the outer panel is removed to open the installation space B downward, as shown in FIG. 13 . Next, the connection lead wire L1 that extends from the control unit (not shown) of the indoor unit 10 and is housed in the installation space B is pulled out. Furthermore, this connection lead wire L1 is connected to the sensor side lead wire L2 that extends from the sensor board 73 and is drawn to the outside of the sensor support member 289, and the sensor support member 289 is then housed in the installation space B.

[0089] Although this modification has been described as including only one refrigerant inlet 286 in housing 280, housing 280 may have two refrigerant inlets (a first refrigerant inlet and a second refrigerant inlet) located on the front (+X) and rear (−X) sides of refrigerant sensor 70. Furthermore, housing 280 may have a third refrigerant inlet that opens into the side wall surface of recess 288.

[0090] Although the embodiments and their modifications of the present disclosure have been described above, the present disclosure is not limited to the configurations of the above-described embodiments and their modifications, and the following configurations and methods may also be employed. Furthermore, the configurations and methods described in this specification may be combined as appropriate within the scope of not mutually contradicting each other.

[0091] For example, in the above-described embodiment, the refrigerant sensor unit is described as being used in a wall-mounted indoor unit, but the refrigerant sensor unit of the embodiment can also be used in other types of indoor units.

[0092] In the above-described embodiment, only the case where the recess is recessed upward and opens downward has been described as an example. However, the recessed direction of the recess is not limited to the above-described embodiment. Furthermore, in the above-described embodiment, the refrigerant sensor has been described as including a substrate, a sensor element, and an element case, but the configuration of the refrigerant sensor is not limited to this.

[0093] DESCRIPTION OF SYMBOLS 10...indoor unit, 20...outdoor unit, 30...refrigerant circuit, 33...refrigerant, 60, 160...refrigerant sensor unit, 70...refrigerant sensor, 71...sensor element, 72...element case, 72h...case opening, 73...sensor board (board), 73a...mounting surface, 78...element, 80, 180...housing, 80f...inner surface, 82t...inclined region, 85...first refrigerant inlet, 86...second refrigerant inlet, 87...third refrigerant inlet, 88...recess, 88a...upper wall surface, 88b...side wall surface, 100...air conditioner, A...accommodation space

Claims

1. An indoor unit for an air conditioner having a refrigerant circuit through which a refrigerant circulates, the indoor unit comprising a refrigerant sensor unit having a refrigerant sensor that detects vaporized refrigerant and a housing that houses the refrigerant sensor, the housing having a first refrigerant inlet that directs the vaporized refrigerant into an accommodation space that houses the refrigerant sensor, and a recessed portion that is provided on the inner surface surrounding the accommodation space and faces the refrigerant sensor.

2. The indoor unit of claim 1, wherein a direction connecting the first refrigerant inlet and the refrigerant sensor is defined as a first direction, a direction perpendicular to the first direction is defined as a second direction, and the recess is recessed in the second direction opposite the refrigerant sensor in the second direction.

3. The indoor unit according to claim 2, wherein the housing has a second refrigerant inlet that guides the vaporized refrigerant into the storage space, and the first refrigerant inlet and the second refrigerant inlet are located on one side and the other side of the refrigerant sensor in the first direction, respectively.

4. An indoor unit as described in claim 2 or 3, wherein the refrigerant sensor comprises: a substrate having a mounting surface; a sensor element mounted on the mounting surface; and a cylindrical element case fixed to the mounting surface, surrounding the sensor element and extending in a direction perpendicular to the mounting surface; a case opening is provided at the end of the element case opposite the mounting surface to guide the vaporized refrigerant into the element case, and the case opening faces the recess in the second direction.

5. The indoor unit according to claim 4, wherein the recess is recessed upward, and the case opening opens upward below the recess.

6. An indoor unit according to any one of claims 1 to 5, wherein the recess has an upper wall surface facing downward and a side wall surface extending downward from the upper wall surface and facing horizontally, and the housing has a third refrigerant inlet opening in the side wall surface.

7. The indoor unit according to claim 6, wherein an inclined region continuous with the lower edge of the third refrigerant inlet is provided on the upper surface of the housing, and the inclined region inclines downward with increasing distance from the third refrigerant inlet.

8. An indoor unit according to any one of claims 1 to 7, wherein the housing comprises: a base member; and a sensor support member that supports the refrigerant sensor and is detachably attached to the base member.

9. An air conditioner comprising: an indoor unit according to any one of claims 1 to 8; the refrigerant circuit; and an outdoor unit.

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