Air conditioning device

Abstract

An air conditioning device comprising: a heat exchanger (40) that includes aluminum or aluminum-alloy heat transfer tubes (27) and an aluminum or aluminum-alloy tube plate (26); a drain pan (60) that receives water generated by the heat exchanger (40); and an antibacterial agent (71) that is disposed in the drain pan (60) and elutes cations of a metal having a higher ionization tendency than aluminum, wherein a plurality of first connection holes (S1) to which the heat transfer tubes (27) are connected are provided in the tube plate (26), and the lowermost first connection hole (SA) among the plurality of first connection holes (S1) is positioned higher than the water level of the drain pan (60).

Description

air conditioning equipment

[0001] The present disclosure relates to an air conditioning apparatus.

[0002] The air conditioning apparatus described in Patent Document 1 includes an antibacterial member placed in a drain pan. The antibacterial member is filled with an antibacterial agent. The antibacterial agent dissolves into the drain water in the drain pan, thereby suppressing the growth of bacteria and mold that may occur in the drain pan. Patent Document 1 discloses the use of an inorganic antibacterial agent primarily composed of inorganic compounds such as silver, copper, zinc, and tin as the antibacterial agent.

[0003] Japanese Patent Application Laid-Open No. 2006-170478

[0004] In recent years, the use of aluminum for heat exchanger components has been attracting attention from the perspectives of weight reduction, improved heat transfer coefficient, cost reduction, etc. However, even if the heat exchanger components are made of aluminum, if the inorganic compounds described above are used as antibacterial agents, and the connections between the tube sheet and the heat transfer tubes in the heat exchanger are flooded with drain water containing cations eluted from the antibacterial agent, the difference in ionization tendency will cause corrosion of the connections, which will loosen the connections and potentially lead to poor connections between the tube sheet and the heat transfer tubes.

[0005] An object of the present disclosure is to provide an air conditioning apparatus that can prevent poor connections between a tube sheet and a heat transfer tube from occurring.

[0006] The air conditioning apparatus of a first aspect includes a heat exchanger (40) including a heat transfer tube (27) made of aluminum or an aluminum alloy and a tube plate (26) made of aluminum or an aluminum alloy, a drain pan (60) that receives water generated in the heat exchanger (40), and an antibacterial agent (71) that is arranged in the drain pan (60) and elutes cations of a metal that has an ionization tendency more noble than aluminum, wherein the tube plate (26) is provided with a plurality of first connection holes (S1) to which the heat transfer tubes (27) are connected, and the lowest first connection hole (SA) of the plurality of first connection holes (S1) is located above the water level in the drain pan (60).

[0007] In the first aspect, it is possible to prevent poor connection between the tube plate (26) and the heat transfer tube (27).

[0008] In the second aspect, in the first aspect, the heat transfer tube (27) is fixed to the first connection hole (S1) of the tube plate (26) only by the tube expansion force of the heat transfer tube (27).

[0009] In the second aspect, the first connection hole (SA), which is located lowest among the plurality of first connection holes (S1), is located at a position higher than the water level in the drain pan (60), thereby preventing poor connection between the tube plate (26) and the heat transfer tube (27). Therefore, even if the heat transfer tube (27) is fixed to the first connection hole (S1) of the tube plate (26) only by the tube expansion force of the heat transfer tube (27), the state in which the heat transfer tube (27) is fixed to the tube plate (26) can be effectively maintained.

[0010] In a third aspect, in the first or second aspect, the heat exchanger (40) includes fins (F), and the fins (F) are provided with second connection holes (T) to which the heat transfer tubes (27) are connected, and burring is formed in the second connection holes (T) of the fins (F), and no burring is formed in the first connection holes (S1) of the tube plate (26).

[0011] In the third aspect, the first connection hole (SA), which is located lowest among the plurality of first connection holes (S1), is located at a position higher than the water level in the drain pan (60), thereby preventing poor connection between the tube plate (26) and the heat transfer tube (27). Therefore, even if burring is not formed in the first connection hole (S1), the heat transfer tube (27) can be effectively maintained in a fixed state to the tube plate (26).

[0012] In a fourth aspect, in any one of the first to third aspects, the heat exchanger (40) includes fins (F), and the tube sheet (26) has an ionization tendency lower than that of the fins (F).

[0013] In the fourth aspect, the first connection hole (SA), which is located lowest among the plurality of first connection holes (S1), is located at a position higher than the water level in the drain pan (60), thereby preventing poor connection between the tube plate (26) and the heat transfer tubes (27). Therefore, even if the tube plate (26) has a lower ionization tendency than the fins (F), the heat transfer tubes (27) can be effectively maintained in a state where they are fixed to the tube plate (26).

[0014] A fifth aspect is any one of the first to fourth aspects, wherein the heat exchanger (40) includes fins (F), and a protective layer is provided on the surface of the fins (F), and no protective layer is provided on the surface of the tube sheet (26).

[0015] In the fifth aspect, the first connection hole (SA), which is located lowest among the plurality of first connection holes (S1), is located at a position higher than the water level in the drain pan (60), thereby preventing poor connection between the tube plate (26) and the heat transfer tubes (27). Therefore, even if a protective layer is not formed on the surface of the tube plate (26), the heat transfer tubes (27) can be effectively maintained in a fixed state to the tube plate (26).

[0016] In a sixth aspect, in any one of the first to fifth aspects, a metal plate (Z) having an ionization tendency more noble than aluminum is provided on the bottom surface (68) of the drain pan (60).

[0017] In the sixth aspect, it is possible to prevent slime from forming on the bottom surface (68) of the drain pan (60).

[0018] In a seventh aspect, in any one of the first to sixth aspects, the drain pan (60) further includes a metal particle inclusion body provided on the bottom surface (68) thereof, the metal particle inclusion body containing metal particles having an ionization tendency more noble than aluminum.

[0019] In the seventh aspect, it is possible to prevent slime from forming on the bottom surface (68) of the drain pan (60).

[0020] In an eighth aspect, in the sixth aspect, the metal plate (Z) is located closer to the drain outlet (V) of the drain pan (60) than the antibacterial agent (71).

[0021] In the eighth aspect, the antibacterial effect of the metal plate (Z) can prevent the drain outlet (V) from being clogged with slime.

[0022] In a ninth aspect, in the seventh aspect, the metal particle containing material is located closer to the drain outlet (V) of the drain pan (60) than the antibacterial agent (71).

[0023] In the ninth aspect, the antibacterial effect on the surface of the metal particle containing body can prevent the drain outlet (V) from being clogged with slime.

[0024] In a tenth aspect, in any one of the first to ninth aspects, the air conditioning apparatus includes a storage section (80) that stores the antibacterial agent (71), and the storage section (80) has a shape that tapers downward.

[0025] In the tenth aspect, it is possible to prevent the connection between the tube plate (26) and the heat transfer tube (27) from being corroded by water containing cations eluted from the antibacterial agent (71).

[0026] An eleventh aspect is any one of the first to tenth aspects, further comprising a storage section (80) that stores the antibacterial agent (71), the storage section (80) including an elution section (H) that sends cations eluted from the antibacterial agent (71) to the outside of the storage section (80), and the first connection hole (SA) that is located lowest among the plurality of first connection holes (S1) is located at a position higher than the upper end of the elution section (H).

[0027] In the eleventh aspect, it is possible to prevent the connection between the tube plate (26) and the heat transfer tube (27) from being corroded by water containing cations eluted from the antibacterial agent (71).

[0028] A twelfth aspect is any one of the first to eleventh aspects, wherein the antibacterial agent (71) is placed toward the center of the drain pan (60) in the longitudinal direction.

[0029] In the twelfth aspect, the cations eluted from the antibacterial agent (71) can be spread over a wide area in the drain pan (60).

[0030] In a thirteenth aspect, in any one of the first to twelfth aspects, a plurality of the heat transfer tubes (27) are connected to the tube plate (26), and the distance (Y) between adjacent ones of the plurality of first connection holes (S1) is 8 mm or more and 17 mm or less.

[0031] In the thirteenth aspect, the evaporator efficiency of the heat exchanger (40) can be effectively ensured, and therefore a large amount of water generated by dehumidification is sent from the heat exchanger (40) to the drain pan (60). However, the water in the drain pan (60) can be made antibacterial by the cations eluted from the antibacterial agent (71), and therefore the risk of slime or grease forming in the drain pan (60) can be reduced.

[0032] FIG. 1 is a schematic piping diagram of an air conditioning apparatus according to an embodiment. FIG. 2 is a front view of an indoor unit. FIG. 3 is a vertical cross-sectional view showing the internal structure of the indoor unit when the indoor unit is cut at a location where fins are located. FIG. 4 is a vertical cross-sectional view showing the internal structure of the indoor unit when the indoor unit is cut at a location where a tube plate is located. FIG. 5 is a vertical cross-sectional view showing an enlarged portion of the internal structure of the indoor unit, around a drain pan. FIG. 6 is a perspective view of a drain pan. FIG. 7 is a perspective view showing a portion of the drain pan. FIG. 8 is a perspective view showing the appearance of a case. FIG. 9 is a perspective view showing a modified example of a drain pan. FIG. 10(a) is a graph showing the relationship between the distance between adjacent heat transfer tubes and evaporator efficiency. FIG. 10(b) is a diagram showing the distance between adjacent heat transfer tubes.

[0033] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below, and various modifications are possible within the scope of the technical concept of the present disclosure. Since each drawing is intended to conceptually explain the present disclosure, dimensions, ratios, or numbers may be exaggerated or simplified as necessary to facilitate understanding. In each embodiment, each example, each modified example, and in each drawing, the same or equivalent parts are designated by the same reference symbols, and detailed descriptions and descriptions of the accompanying effects will not be repeated.

[0034] (1) Overall Configuration of an Air Conditioning Apparatus FIG. 1 shows a schematic piping diagram of an air conditioner (10). The air conditioner (10) adjusts the temperature of air in a target space. The target space is an indoor space. The air conditioner (10) performs cooling operation and heating operation. In cooling operation, the air conditioner (10) cools the air in the indoor space. In heating operation, the air conditioner (10) heats the air in the indoor space.

[0035] The air conditioner (10) includes a refrigerant circuit (11). The refrigerant circuit (11) is filled with a refrigerant. The refrigerant circuit (11) performs a refrigeration cycle by circulating the refrigerant. The refrigerant circuit (11) is filled with a flammable refrigerant. In this example, the refrigerant contains difluoromethane (R32). The refrigerant may also contain propane (R290), which is a highly flammable natural refrigerant. Natural refrigerants have an ozone depletion potential of zero, a low global warming potential, and are environmentally friendly.

[0036] The air conditioner (10) includes an outdoor unit (20), an indoor unit (30), a first connecting pipe (12), and a second connecting pipe (13). The air conditioner (10) is a pair type having one outdoor unit (20) and one indoor unit (30). The outdoor unit (20) includes a compressor (21), an outdoor heat exchanger (22), an expansion valve (23), a four-way switching valve (24), and an outdoor fan (25). The indoor unit (30) includes an indoor heat exchanger (40) and a cross-flow fan (50).

[0037] (1-1) Outdoor Unit The outdoor unit (20) is installed in the outdoor space.

[0038] The compressor (21) compresses the refrigerant. The compressor (21) is a rotary compressor. The rotary compressor (21) is of a swing type, a rolling piston type, a scroll type, or the like.

[0039] The outdoor heat exchanger (22) exchanges heat between the refrigerant and outdoor air and is of a fin-and-tube type.

[0040] The outdoor fan (25) transports outdoor air. The air transported by the outdoor fan (25) passes through the outdoor heat exchanger (22). The outdoor fan (25) is a propeller fan.

[0041] The expansion valve (23) reduces the pressure of the refrigerant and is an electronic or temperature-sensitive expansion valve.

[0042] The four-way selector valve (24) reverses the flow of refrigerant in the refrigerant circuit (11). The four-way selector valve (24) switches between a first state shown by a solid line in Fig. 1 and a second state shown by a dashed line in Fig. 1. In the first state, the four-way selector valve (24) connects the discharge side of the compressor (21) to the gas side of the outdoor heat exchanger (22) and also connects the suction side of the compressor (21) to the gas side of the indoor heat exchanger (40). In the second state, the four-way selector valve (24) connects the discharge side of the compressor (21) to the gas side of the indoor heat exchanger (40) and also connects the suction side of the compressor (21) to the gas side of the outdoor heat exchanger (22).

[0043] (1-2) Indoor Unit The indoor unit (30) is installed in a room.

[0044] The indoor heat exchanger (40) exchanges heat between the refrigerant and the indoor air and is of a fin-and-tube type.

[0045] The cross flow fan (50) is an indoor fan that transports indoor air. The air transported by the cross flow fan (50) passes through the indoor heat exchanger (40).

[0046] (1-3) First Interconnection Pipe and Second Interconnection Pipe The first interconnection pipe (12) and the second interconnection pipe (13) connect the indoor unit (30) and the outdoor unit (20) to each other. The first interconnection pipe (12) is a gas pipe, and the second interconnection pipe (13) is a liquid pipe. The first interconnection pipe (12) is connected to the gas end of the indoor heat exchanger (40). The second interconnection pipe (13) is connected to the liquid end of the indoor heat exchanger (40).

[0047] (2) Details of the Indoor Unit Figure 2 shows the indoor unit (30). Figure 3 is a longitudinal cross-sectional view of the indoor unit (30). In the following description, the terms "upper," "lower," "front," "rear," "left," and "right" refer to directions when the indoor unit (30) is viewed from the front.

[0048] The indoor unit (30) is mounted on a wall. The indoor unit (30) is a wall-mounted air conditioning indoor unit. The indoor unit (30) includes a casing (31), an indoor heat exchanger (40), a drain pan (60), and an antibacterial unit (70).

[0049] (2-1) Casing The casing (31) forms the outer shell of the indoor unit (30). An internal space (39) is formed inside the casing (31) to accommodate the indoor heat exchanger (40) and the cross-flow fan (50).

[0050] 2 and 3, the casing (31) is formed in the shape of a horizontally elongated box extending in the left-right direction. The casing (31) has a front plate portion (32), a rear plate portion (33), an upper plate portion (34), and a lower plate portion (35).

[0051] The casing (31) has a suction opening (36). The suction opening (36) is formed in the upper plate portion (34) of the casing (31). The suction opening (36) extends in the longitudinal direction (left-right direction) of the casing (31). The suction opening (36) takes in air from the indoor space into an internal space (39) of the casing (31).

[0052] The casing (31) has an outlet opening (37). The outlet opening (37) is formed in the lower plate portion (35). The outlet opening (37) extends in the longitudinal direction of the casing (31). The outlet opening (37) blows the air that has flowed through the outlet flow path (38) into the indoor space. The outlet opening (37) is provided with two flaps (55). Each flap (55) adjusts the direction of the air blown out of the outlet opening (37).

[0053] (2-2) Indoor Heat Exchanger The indoor heat exchanger (40) exchanges heat with air using a refrigerant flowing through the heat transfer tubes (27). As shown in FIGS. 2 to 4, the indoor heat exchanger (40) includes a tube plate (26), a plurality of heat transfer tubes (27), and a plurality of fins (F). The tube plate (26), the heat transfer tubes (27), and the fins (F) are made of aluminum or an aluminum alloy. The tube plate (26) supports the heat transfer tubes (27) and the fins (F). The tube plate (26) is formed in a plate shape. The tube plate (26) has a plurality of holes (S) penetrating therethrough. A plurality of fins (F) are disposed between the pair of tube plates (26). In this embodiment, the pair of tube plates (26) are disposed on both the left and right sides of the plurality of fins (F). The plurality of heat transfer tubes (27) extend in the left-right direction. Each of the plurality of heat transfer tubes (27) is connected to (inserted through) one of the plurality of holes (S).

[0054] Among the multiple holes (S), a hole (S) to which a heat transfer tube (27) is connected may be referred to as a first connection hole (S1). Among the multiple holes (S), a hole (S) that does not correspond to the first connection hole (S1), i.e., a hole (S) that is open because a heat transfer tube (27) is not connected, may be referred to as an open hole (S2). By connecting the heat transfer tube (27) to all of the multiple holes (S), all of the holes (S) may constitute the first connection holes (S1). Furthermore, by connecting the heat transfer tube (27) to some of the multiple holes (S), some of the holes (S) may constitute the first connection holes (S1) and the remaining holes (S) may constitute the open holes (S2).

[0055] The fins (F) are formed in a plate shape. The fins (F) are arranged at equal intervals along the direction of the axis O (left-right direction) of the cross flow fan (50). The fins (F) are provided with a plurality of second connection holes (T) that penetrate the fins (F). The heat transfer pipes (27) are connected to (inserted through) the second connection holes (T). The interior of the heat transfer pipes (27) forms a flow path for the refrigerant. The heat transfer pipes (27) constitute a part of the refrigerant circuit (11).

[0056] The indoor heat exchanger (40) includes a front heat exchange section (41) and a rear heat exchange section (42). The indoor heat exchanger (40) further includes a front auxiliary heat exchange section (43) and a rear auxiliary heat exchange section (44). The front heat exchange section (41), the rear heat exchange section (42), the front auxiliary heat exchange section (43), and the rear auxiliary heat exchange section (44) are configured as separate entities.

[0057] (2-3) Drain Pan The drain pan (60) is disposed below the indoor heat exchanger (40). Specifically, the drain pan (60) is disposed below the front heat exchange section (41) and the front auxiliary heat exchange section (43). The drain pan (60) receives water generated in the indoor heat exchanger (40) and thereby stores the water generated in the indoor heat exchanger (40). Hereinafter, the water stored in the drain pan (60) may be referred to as drain water.

[0058] As shown in Figures 5 and 6, the drain pan (60) is formed in the shape of a horizontally elongated box extending in the left-right direction. The drain pan (60) has a bottom plate (61), a front wall (62), a rear wall (63), a right side wall (64), and a left side wall (65). The left-right direction indicates the longitudinal direction of the drain pan (60). In other words, the left-right direction is the width direction of the drain pan (60). The front-rear direction is a direction perpendicular to the left-right direction and indicates the width direction of the drain pan (60). In other words, the front-rear direction is the depth direction of the drain pan (60). The up-down direction is the vertical direction. The up-down direction is a direction perpendicular to the left-right direction and the front-rear direction. In other words, the up-down direction is the height direction of the drain pan (60).

[0059] The bottom plate (61) includes a first bottom plate (61a) and a second bottom plate (61b). The first bottom plate (61a) and the second bottom plate (61b) are generally rectangular. The first bottom plate (61a) has a generally horizontal surface. The second bottom plate (61b) is formed so as to slope upward as it extends rearward from the rear end of the first bottom plate (61a).

[0060] The front wall (62) is formed so as to slope forward as it extends upward from the front end of the first bottom plate (61a). The rear wall (63) extends upward from the rear end of the second bottom plate (61b). The right side wall (64) is connected to the right end of the bottom plate (61). The left side wall (65) is connected to the left end of the bottom plate (61).

[0061] The drain pan (60) is provided with a drain outlet (V) that connects the inside and outside of the drain pan (60). Drain water is discharged to the outside of the drain pan (60) through the drain outlet (V). In this embodiment, the drain outlet (V) includes a first drain outlet (V1) and a second drain outlet (V2). The first drain outlet (V1) and the second drain outlet (V2) are holes to which drain hoses are connected. The first drain outlet (V1) is provided at one left end (left end) of the drain pan (60), and the second drain outlet (V2) is provided at the other left end (right end) of the drain pan (60). The drain water flows into the drain hose via the first drain outlet (V1) or the second drain outlet (V2) to which the drain hose is connected.

[0062] As shown in FIG. 7 , the drain pan (60) is formed with a first fixing portion (66) and a second fixing portion (67) for fixing the position of the antibacterial portion (70). The first fixing portion (66) is formed at the center and upper end of the front wall (62) in the left-right direction. The first fixing portion (66) is formed so that the upper end of the front wall (62) is recessed. A first tongue portion (77c) (described in detail below) provided on the antibacterial portion (70) fits into the first fixing portion (66). The second fixing portion (67) is formed at the center and lower end of the front wall (62) in the left-right direction. The second fixing portion (67) has a rectangular first plate (67a) extending rearward from the lower end of the front wall (62) and a second plate (67b) connected to the rear end of the first plate (67a) and extending in the left-right direction. A second tongue portion (77d) (to be described in detail later) provided on the antibacterial portion (70) fits into the second fixing portion (67).

[0063] (3) Antibacterial Unit As shown in FIGS. 3 to 6 , the antibacterial unit (70) is disposed in the drain pan (60). The antibacterial unit (70) is disposed near the front wall (62) of the drain pan (60). The antibacterial unit (70) includes an antibacterial agent (71) and a case (72) that accommodates the antibacterial agent (71). The antibacterial agent (71) has an antibacterial effect on drain water. In this embodiment, "antibacterial" includes sterilization or disinfection. The case (72) includes a container (80) and a lid (73). The container (80) accommodates the antibacterial agent (71). The container (80) (antibacterial agent (71)) is disposed near the center in the left-right direction of the drain pan (60).

[0064] The storage section (80) has a shape that tapers downward, that is, the cross-sectional area of ​​the storage section (80) perpendicular to the up-down direction decreases downward.

[0065] 5 and 8, the storage section (80) is formed in the shape of a hollow box with an open top. The opening at the top of the storage section (80) is closed by the lid (73) attached thereto.

[0066] The storage section (80) is formed with a plurality of holes (H) communicating with the inside and outside of the storage section (80). The holes (H) are formed in the front side surfaces (84, 86, 87) and the bottom (81) of the storage section (80). The antibacterial agent (71) is a plurality of granules. The antibacterial agent (71) contains a metal having an ionization tendency more noble than aluminum. The antibacterial agent (71) contains, for example, silver, copper, stainless steel, and / or zinc. The antibacterial agent (71) elutes cations of the metal having an ionization tendency more noble than aluminum upon contact with drain water.

[0067] The accommodation portion (80) is formed with a flange portion (92). The flange portion (92) is provided with a second tongue portion (77d). The second tongue portion (77d) is formed with a slit (79) extending from the lower end to the upper end. The first plate (67a) of the second fixing portion (67) is inserted into the slit (79).

[0068] The lid portion (73) has a hook portion (77). The hook portion (77) has a base portion (77a), an arm portion (77b), and a first tongue portion (77c). The base portion (77a) extends upward from the front portion of the lid portion (73). The arm portion (77b) extends generally horizontally from the upper end of the base portion (77a) toward the front wall (62) of the drain pan (60). The first tongue portion (77c) extends downward from the rear end of the arm portion (77b). A groove portion (78) is formed at the connection portion between the first tongue portion (77c) and the arm portion (77b). The groove portion (78) is positioned to fit into the first fixing portion (66).

[0069] Drain water flows in and out of the storage portion (80) through the holes (H). As the drain water flows into the storage portion (80) through the holes (H), the drain water comes into contact with the antibacterial agent (71) in the storage portion (80). As a result, cations of a metal having a more noble ionization tendency than aluminum are eluted from the antibacterial agent (71), and the cations flow into the drain pan (60) (outside the storage portion (80)) through the holes (H). This allows the cations to exert an antibacterial effect on the drain water. As a result, the generation of slime in the drain pan (60) can be suppressed. The holes (H) are an example of an elution portion.

[0070] (4) Features: The tube plate (26) is provided with a plurality of first connection holes (S1) to which the heat transfer tubes (27) are connected. The first connection hole (SA), which is the lowest of the plurality of first connection holes (S1), is located above the water level of the drain pan (60). The water level of the drain pan (60) indicates the position of the upper end of the drain outlet (V) of the drain pan (60) in the vertical direction (in this embodiment, the position of the upper end of the circular two-dot chain line illustrating the drain outlet (V) in FIG. 4). When a plurality of drain outlets (V) (a first drain outlet (V1) and a second drain outlet (V2)) are arranged as in this embodiment, the water level of the drain pan (60) indicates the position of the upper end of the uppermost drain outlet (V) of the plurality of drain outlets (V) in the vertical direction.

[0071] (5) Effect As described above, the first connection hole (SA), which is the lowest of the plurality of first connection holes (S1), is located above the water level in the drain pan (60) (see FIG. 4 ). This allows drain water to be discharged to the outside of the drain pan (60) through the drain outlet (V) before the drain water reaches the first connection hole (SA). This prevents the connection (first connection hole (S1)) between the tube sheet (26) and the heat transfer tube (27) from being flooded with drain water containing cations eluted from the antibacterial agent (71). As a result, corrosion (galvanic corrosion) of the connection between the tube sheet (26) and the heat transfer tube (27) is prevented, thereby preventing poor connection between the tube sheet (26) and the heat transfer tube (27).

[0072] Furthermore, poor connection between the tube plate (26) and the heat transfer tube (27) can create a gap between the first connection hole (S1) of the tube plate (26) and the heat transfer tube (27), and drain water containing cations eluted from the antibacterial agent (71) can accumulate in this gap, thereby preventing an increase in the risk of corrosion of the heat transfer tube (27).

[0073] Furthermore, the accommodation portion (80) has a shape that tapers downward (see FIGS. 5 and 8 ). As a result, even if a tapered shape is adopted for the accommodation portion (80), that is, a shape in which the contact area between the drain water and the accommodation portion (80) increases as the water level in the drain pan (60) increases and more cations are eluted from the antibacterial agent (71), the first connection hole (SA) is located at a position higher than the water level in the drain pan (60), thereby preventing the connection portion between the tube plate (26) and the heat transfer tube (27) from being submerged in water, and thus preventing corrosion of the connection portion between the tube plate (26) and the heat transfer tube (27) due to drain water containing cations eluted from the antibacterial agent (71).

[0074] The antibacterial agent (71) is disposed toward the center of the drain pan (60) in the longitudinal direction (see FIG. 6 ), which prevents cations eluted from the antibacterial agent (71) from being accumulated in a specific area in the drain pan (60) and allows the cations to be distributed over a wide area in the drain pan (60).

[0075] Although the embodiments and modifications have been described above, it will be understood that various modifications of form and details are possible without departing from the spirit and scope of the claims (for example, modifications (A) to (J) below).

[0076] (A) The heat transfer tube (27) may be fixed to the first connecting hole (S1) of the tube plate (26) only by the tube expansion force of the heat transfer tube (27) (see FIG. 4). In this case, the first connecting hole (SA) is located higher than the water level in the drain pan (60), thereby preventing poor connection between the tube plate (26) and the heat transfer tube (27). Therefore, even if the heat transfer tube (27) is fixed to the first connecting hole (S1) of the tube plate (26) only by the tube expansion force of the heat transfer tube (27), the state in which the heat transfer tube (27) is fixed to the tube plate (26) can be effectively maintained.

[0077] (B) Burring may be formed in the second connection holes (T) of the fins (F), but no burring may be formed in the first connection holes (S1) of the tube plate (26) (see FIGS. 3 and 4). In this way, the first connection holes (SA) are located higher than the water level in the drain pan (60), thereby preventing poor connection between the tube plate (26) and the heat transfer tubes (27). Therefore, even if no burring is formed in the first connection holes, the heat transfer tubes (27) can be effectively maintained in a fixed state to the tube plate (26).

[0078] (C) The tube sheet (26) may have a lower ionization tendency than the fins (F). In this case, the tube sheet (26) is made of aluminum or an aluminum alloy, and the fins (F) are made of, for example, copper or stainless steel. With this, the first connection hole (SA) is located higher than the water level in the drain pan (60), thereby preventing poor connection between the tube sheet (26) and the heat transfer tubes (27). Therefore, even if the tube sheet (26) has a lower ionization tendency than the fins (F), the heat transfer tubes (27) can be effectively maintained in a state where they are fixed to the tube sheet (26).

[0079] (D) A protective layer may be provided on the surface of the fin (F), while no protective layer may be provided on the surface of the tube sheet (26). The protective layer is a film that covers an object to prevent electrolytic corrosion of the object. Protective layers include not only layers (sacrificial layers) having a lower potential than the object on which the protective layer is provided, but also resin coating layers. In this embodiment, a sacrificial layer formed by, for example, zinc spraying is provided on the surface of the aluminum or aluminum alloy fin (F). In contrast, the surface of the aluminum or aluminum alloy tube sheet (26) is exposed without a protective layer. This prevents poor connection between the tube sheet (26) and the heat transfer tube (27) by positioning the first connection hole (SA) higher than the water level in the drain pan (60). Therefore, even if a protective layer is not formed on the surface of the tube sheet (26), the heat transfer tube (27) can be effectively maintained in a fixed state to the tube sheet (26).

[0080] (E) As shown in FIG. 9 , the indoor unit (30) (antibacterial unit (70)) may further include a metal plate (Z) that is a plate-shaped metal. The metal plate (Z) contains a metal that has a more noble ionization tendency than aluminum. The metal plate (Z) contains, for example, silver, copper, stainless steel, and / or zinc. The metal plate (Z) is provided on the bottom surface (68) of the drain pan (60). The metal plate (Z) is fixed to the bottom surface (68) of the drain pan (60) with, for example, screws or tape (including double-sided tape). The metal plate (Z) elutes cations of a metal that has a more noble ionization tendency than aluminum upon contact with drain water. This allows the cations eluted from the metal plate (Z) to pinpoint antibacterial properties of the drain water near the bottom surface (68) of the drain pan (60), where slime and grease are likely to form, thereby more effectively suppressing the formation of slime and grease.

[0081] (F) The metal plate (Z) may be located closer to the drain outlet (V) than the antibacterial agent (71). For example, as shown in FIG. 9 , if the first drain outlet (V1) is located at the left end of the drain pan (60) and the second drain outlet (V2) is located at the right end of the drain pan (60), the antibacterial agent (71) is located closer to the center of the drain pan (60) in the left-right direction, the first metal plate (Z1) is located closer to the left of the drain pan (60), and the second metal plate (Z2) is located closer to the right of the drain pan (60). This allows the antibacterial effect of the metal plate (Z) to be exerted near the drain outlet (V), thereby preventing the drain outlet (V) from being clogged with slime.

[0082] (G) The indoor unit (30) (antibacterial section (70)) may further include a metal particle inclusion. The metal particle inclusion contains metal particles (metal powder). The metal particles contain a metal that has a more noble ionization tendency than aluminum. The metal particles contain, for example, silver, copper, stainless steel, and / or zinc. The metal particle inclusion is provided on the bottom surface (68) of the drain pan (60).

[0083] The metal particles may be contained in a water-soluble paint. In this case, the paint is applied to the bottom surface (68) of the drain pan (60), thereby providing the metal particles on the bottom surface (68) of the drain pan (60). In this case, the paint serves as the metal particle inclusion. Alternatively, the metal particles may be attached to the surface of a sealant disposed on the bottom surface (68) of the drain pan (60). In this case, the sealant serves as the metal particle inclusion. Alternatively, the metal particles may be disposed on the bottom surface (68) of the drain pan (60) by being kneaded into the drain pan (60). In this case, the portion of the drain pan (60) into which the metal particles are kneaded serves as the metal particle inclusion. Alternatively, the metal particles may be disposed on the bottom surface (68) of the drain pan (60) while being contained in a bag-like member having a mesh, such as a net. In this case, the bag-like member serves as the metal particle inclusion.

[0084] When the metal particle-containing body is immersed in drain water, cations of a metal with a noble ionization tendency are eluted from the metal particle-containing body into the drain water. The metal particle-containing body (metal particles) elutes cations of a metal with a noble ionization tendency more noble than aluminum upon contact with the drain water. As a result, the cations eluted from the metal particles can pinpoint antibacterial properties of the drain water near the bottom surface (68) of the drain pan (60), where slime and slime are likely to form, thereby more effectively suppressing the formation of slime and slime.

[0085] (H) The metal particle inclusions may be located closer to the drain outlet (V) than the antibacterial agent (71). This allows the antibacterial action of the metal particles contained in the metal particle inclusions to be exerted near the drain outlet (V), thereby preventing the drain outlet (V) from being clogged with slime.

[0086] (I) The lowest first connection hole (SA) among the plurality of first connection holes (S1) may be located higher than the upper end of the elution portion. The upper end of the elution portion is the upper end of a portion of the accommodation portion (80) that connects the interior and exterior of the accommodation portion (80) and allows drain water to flow between the interior and exterior of the accommodation portion (80). In this embodiment, the upper end of the elution portion is the upper end of the uppermost hole (H) among the plurality of holes (H) (see FIG. 8 ). This prevents the connection portion (first connection hole (S1)) between the tube sheet (26) and the heat transfer tube (27) from being flooded with drain water containing cations eluted from the antibacterial agent (71) to the outside of the accommodation portion (80). This prevents corrosion of the connection portion between the tube sheet (26) and the heat transfer tube (27).

[0087] (J) As shown in FIGS. 10( a) and 10(b), the distance (Y) between adjacent heat transfer tubes (27) may be 8 mm or more and 17 mm or less. The distance (Y) between adjacent heat transfer tubes (27) is, in other words, the distance (Y) between adjacent first connection holes (S1). The inventors of the present application have conducted tests and confirmed that, while the evaporator efficiency improves when the distance (Y) between adjacent heat transfer tubes (27) is reduced, when the distance (Y) between adjacent heat transfer tubes (27) is less than 8 mm, the resistance to airflow through the indoor heat exchanger (40) increases, necessitating an increase in the rotation speed of the fan (50). This increases the power consumption of the fan (50), but the improvement in evaporator efficiency is relatively small. Furthermore, the inventors of the present application have confirmed that when the distance (Y) between adjacent heat transfer tubes (27) is greater than 17 mm, the evaporator efficiency deteriorates below the desired standard. Therefore, in order to effectively ensure the evaporator efficiency while also taking into consideration the running costs of the air conditioner (10), the distance (Y) between adjacent heat transfer tubes (27) is set to 8 mm or more and 17 mm or less. In this way, since the heat exchanger (22) effectively performs dehumidification, a large amount of water generated by dehumidification is sent from the heat exchanger (22) to the drain pan (60), but the water in the drain pan (60) can be made antibacterial by cations eluted from the antibacterial agent (71), thereby reducing the risk of slime or slime forming in the drain pan (60). The evaporator efficiency is a value obtained by subtracting the wet-bulb temperature of the outlet air from the wet-bulb temperature of the intake air in the air conditioner (10) (intake air WB - outlet air WB), and dividing this value by the value obtained by subtracting the evaporation temperature from the wet-bulb temperature of the intake air (intake air WB - evaporation temperature) (evaporator efficiency = (intake air WB - outlet air WB) / (intake air WB - evaporation temperature), where WB is the wet bulb (wet-bulb temperature).

[0088] The terms "first," "second," "third," etc. described above are used to distinguish between terms to which these terms are attached, and do not limit the number or order of the terms. Furthermore, the above-described embodiments, examples, modifications, and other embodiments may be combined or substituted as appropriate as long as the functionality of the subject matter of the present disclosure is not impaired.

[0089] INDUSTRIAL APPLICABILITY As described above, the present disclosure is useful for air conditioning apparatuses.

[0090] 10 Air conditioning unit 26 Tube sheet 27 Heat transfer tube 40 Heat exchanger 60 Drain pan 71 Antibacterial agent S1 First connection hole SA The first connection hole located at the bottom

Claims

1. An air conditioning apparatus comprising: a heat exchanger (40) including heat transfer tubes (27) made of aluminum or aluminum alloy and a tube plate (26) made of aluminum or aluminum alloy; a drain pan (60) that receives water generated in the heat exchanger (40); and an antibacterial agent (71) that is disposed in the drain pan (60) and elutes cations of a metal that has an ionization tendency more noble than aluminum; the tube plate (26) is provided with a plurality of first connection holes (S1) to which the heat transfer tubes (27) are connected; and the lowest first connection hole (SA) of the plurality of first connection holes (S1) is located above the water level in the drain pan (60).

2. The air conditioner according to claim 1, wherein the heat transfer tube (27) is fixed to the first connection hole (S1) of the tube plate (26) only by the tube expansion force of the heat transfer tube (27).

3. The air conditioning apparatus of claim 1 or 2, wherein the heat exchanger (40) includes fins (F), the fins (F) are provided with second connection holes (T) to which the heat transfer tubes (27) are connected, the second connection holes (T) of the fins (F) are formed with burring, and the first connection holes (S1) of the tube plate (26) are not formed with burring.

4. The air conditioner according to any one of claims 1 to 3, wherein the heat exchanger (40) includes fins (F), and the tube sheet (26) has an ionization tendency lower than that of the fins (F).

5. The air conditioning apparatus according to any one of claims 1 to 4, wherein the heat exchanger (40) includes fins (F), the surfaces of the fins (F) are provided with a protective layer, and the surface of the tube sheet (26) is not provided with a protective layer.

6. An air conditioner according to any one of claims 1 to 5, further comprising a metal plate (Z) provided on the bottom surface (68) of the drain pan (60) and made of a metal having an ionization tendency more noble than aluminum.

7. An air conditioning apparatus according to any one of claims 1 to 6, further comprising a metal particle inclusion body provided on the bottom surface (68) of the drain pan (60) and containing metal particles having an ionization tendency more noble than aluminum.

8. The air conditioning apparatus according to claim 6, wherein the metal plate (Z) is located closer to the drain outlet (V) of the drain pan (60) than the antibacterial agent (71).

9. The air conditioning apparatus according to claim 7, wherein the metal particle containing material is located closer to the drain outlet (V) of the drain pan (60) than the antibacterial agent (71).

10. An air conditioning apparatus according to any one of claims 1 to 9, comprising a storage section (80) for storing the antibacterial agent (71), the storage section (80) having a shape that tapers downward.

11. An air conditioning apparatus as described in any one of claims 1 to 10, comprising a storage section (80) that stores the antibacterial agent (71), the storage section (80) including an elution section (H) that sends cations eluted from the antibacterial agent (71) to the outside of the storage section (80), and the first connection hole (SA) located lowest among the plurality of first connection holes (S1) is located at a position higher than the upper end of the elution section (H).

12. An air conditioning apparatus according to any one of claims 1 to 11, wherein the antibacterial agent (71) is arranged near the center in the longitudinal direction of the drain pan (60).

13. An air conditioning device as described in any one of claims 1 to 12, wherein a plurality of the heat transfer tubes (27) are connected to the tube plate (26), and the distance (Y) between adjacent first connection holes (S1) is 8 mm or more and 17 mm or less.

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