INDOOR HEAT EXCHANGER AND AIR CONDITIONING APPARATUS

Abstract

An indoor heat exchanger in an indoor unit of an air conditioning apparatus, includes: flat tubes that are juxtaposed in a vertical direction and that each comprise a flow channel that allows refrigerant to pass through an inner portion thereof, and heat transfer fins joined to the flat tubes. The heat transfer fins each include: a first portion that extends continuously in the vertical direction; and second portions that are disposed between the flat tubes. The first portion and the second portions are continuous. 4.0≤DP/HT≤10.0 where HT is a height of each of the flat tubes and DP is a pitch of the flat tubes.

Description

TECHNICAL FIELD

The present invention relates to an indoor heat exchanger and an air conditioning apparatus.

BACKGROUND

As an existing outdoor heat exchanger included in an outdoor unit of an air conditioning apparatus, for example, PTL 1 (Japanese Unexamined Patent Application Publication No. 2016-041986) discloses an outdoor heat exchanger in which heat transfer fins are joined to a plurality of flat tubes.

When such a heat exchanger in which heat transfer fins are joined to a plurality of flat tubes is used in an indoor unit of an air conditioning apparatus, dew condensation water that is generated when the heat exchanger functions as an evaporator for refrigerant disperses into an indoor space.

SUMMARY

One or more embodiments of the present invention provide an indoor heat exchanger including a plurality of flat tubes capable of suppressing dispersion of dew condensation water, and an air conditioning apparatus.

An indoor heat exchanger according to a first aspect is an indoor heat exchanger used in an indoor unit of an air conditioning apparatus. The indoor heat exchanger includes a plurality of flat tubes and a plurality of heat transfer fins. The flat tubes each include a flow channel that allows refrigerant to pass through an inner portion thereof. The plurality of flat tubes are vertically juxtaposed (i.e., disposed in a vertical direction). The plurality of heat transfer fins are joined to the plurality of flat tubes. The heat transfer fins each include a continuous portion. The continuous portion extends vertically (i.e., extends in the vertical direction). The continuous portion of each heat transfer fin is a portion of the heat transfer fin and continuous with portions positioned between the flat tubes vertically juxtaposed. The indoor heat exchanger satisfies the relation of 4.0≤DP/HT≤10.0. HT represents the height of each of the flat tubes. DP represents the pitch of the flat tubes vertically juxtaposed.

The indoor heat exchanger enables, even when the flow rate of the airflow supplied to the indoor heat exchanger is increased, suppression of dispersion of dew condensation water that is generated when the indoor heat exchanger is used as an evaporator for refrigerant.

An indoor heat exchanger according to a second aspect is an indoor heat exchanger used in an indoor unit. The indoor unit constitutes an air conditioning apparatus in cooperation with an outdoor unit that includes an outdoor heat exchanger. The outdoor heat exchanger includes a plurality of flat tubes and a plurality of heat transfer fins. The indoor heat exchanger also includes a plurality of flat tubes and a plurality of heat transfer fins. These flat tubes each include a flow channel that allows refrigerant to pass through an inner portion thereof. The plurality of flat tubes are vertically juxtaposed. The plurality of fins are joined to the plurality of flat tubes. The heat transfer fins each include a continuous portion. The continuous portion extends vertically. The continuous portion of each heat transfer fin is a portion of the heat transfer fin and continuous with portions positioned between the flat tubes vertically juxtaposed. The value of DP/HT of the indoor heat exchanger is smaller than the value of DP/HT of the outdoor heat exchanger. HT represents the height of each of the flat tubes. DP represents the pitch of the flat tubes vertically juxtaposed.

The indoor heat exchanger enables suppression of dispersion of dew condensation water that is generated when the indoor heat exchanger is used as an evaporator for refrigerant while suppressing frost formation that occurs when the outdoor heat exchanger is used as an evaporator for refrigerant.

An indoor heat exchanger according to a third aspect is the indoor heat exchanger according to the first aspect or the second aspect, in which the flat tubes each include a plurality of upstream-side flat tubes disposed on the upstream side in an airflow direction, and a plurality of downstream-side flat tubes disposed on the downstream side in the airflow direction from the upstream-side flat tubes.

The indoor heat exchanger enables suppression of dispersion of dew condensation water from the downstream-side ends of the downstream-side flat tubes in the airflow direction.

An indoor heat exchanger according to a fourth aspect is the indoor heat exchanger according to any one of the first aspect to the third aspect, in which the continuous portion is positioned on the leeward side of the flat tubes in the airflow direction.

The indoor heat exchanger enables suppression of dispersion of dew condensation water from the downstream-side ends of the heat transfer fins in the airflow direction by guiding the dew condensation water that has been generated on the flat tubes to move downward along the continuous portions of the heat transfer fins positioned on the downstream side in the airflow direction.

An indoor heat exchanger according to a fifth aspect is the indoor heat exchanger according to any one of the first aspect to the fourth aspect, in which the relation of 0.2≤WL/WF≤0.5 is satisfied. WF represents the length of each of the heat transfer fins in the airflow direction. WL represents the length of the continuous portion in the airflow direction.

The indoor heat exchanger enables suppression of dispersion of dew condensation water by sufficiently ensuring the continuous portion while suppressing material costs of the heat transfer fins.

An indoor heat exchanger according to a sixth aspect is the indoor heat exchanger according to any one of the first aspect to the fifth aspect, in which the heat transfer fins each include a cut-and-raised portion. The longitudinal direction of the cut-and-raised portion is the up-down direction (i.e., the vertical direction).

Due to the heat transfer fins each including the cut-and-raised portion, the indoor heat exchanger enables an improvement in heat transfer performance.

An indoor heat exchanger according to a seventh aspect is the indoor heat exchanger according to any one of the first aspect to the sixth aspect, in which the relation of 4.6≤DP/HT≤8.0 is satisfied.

The indoor heat exchanger more easily suppresses dispersion of dew condensation water that is generated when the indoor heat exchanger is used as an evaporator for refrigerant.

An air conditioning apparatus according to an eighth aspect includes an indoor unit including the indoor heat exchanger according to any one of the first aspect to the seventh aspect, and an outdoor unit including an outdoor heat exchanger.

The air conditioning apparatus easily suppresses dispersion of dew condensation water that is generated when the indoor heat exchanger is used as an evaporator for refrigerant.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of air conditioning apparatus.

FIG. 2 is a perspective view schematically illustrating the external appearance of an outdoor unit.

FIG. 3 is a schematic plan view of an outdoor unit.

FIG. 4 is a perspective view schematically illustrating the external appearance of an outdoor heat exchanger.

FIG. 5 is an illustration of a positional relation between outdoor fins and outdoor flat tubes.

FIG. 6 is a perspective view schematically illustrating the external appearance of an indoor unit.

FIG. 7 is a schematic plan view of an indoor unit.

FIG. 8 is a schematic side view of the indoor unit along the A-A section of FIG. 7.

FIG. 9 is a perspective view schematically illustrating the external appearance of an indoor heat exchanger.

FIG. 10 is a partially enlarged perspective view schematically illustrating the external appearance of the indoor heat exchanger.

FIG. 11 is an illustration of the positional relation between indoor fins and indoor flat tubes.

FIG. 12 is an illustration of a joined state between the indoor fins and the indoor flat tubes.

FIG. 13 is an illustration of the positional relation between indoor fins and indoor flat tubes according to a modification A.

FIG. 14 is an illustration of a portion of a water-guiding rib included in each of the indoor fins according to the modification A, along the B-B section of FIG. 13, the portion being in the vicinity of the downstream side in an airflow direction.

DETAILED DESCRIPTION

(1) Configuration of Air Conditioning Apparatus

FIG. 1 is a schematic diagram of an air conditioning apparatus 1.

The air conditioning apparatus 1 is an apparatus capable of cooling and heating a room of a building or the like by performing a vapor compression refrigeration cycle.

The air conditioning apparatus 1 includes, mainly, an outdoor unit 2, an indoor unit 3, and a liquid-refrigerant connection pipe 4 and a gas-refrigerant connection pipe 5 that are refrigerant paths connecting the outdoor unit 2 and the indoor unit 3 to each other. A vapor compression refrigerant circuit 6 of the air conditioning apparatus 1 is constituted by the outdoor unit 2 and the indoor unit 3 being connected to each other via the refrigerant connection pipes 4 and 5. The refrigerant connection pipes 4 and 5 are refrigerant pipes that are constructed locally during installation of the air conditioning apparatus 1 in an installation location in a building or the like. In one or more embodiments, the refrigerant circuit 6 is packed with R32 as a working refrigerant; however, the working refrigerant is not limited thereto.

(2) Outdoor Unit

(2-1) General Configuration of Outdoor Unit

The outdoor unit 2 is installed outside (for example, on the rooftop of a building or in the vicinity of a wall surface of a building) and constitutes a portion of the refrigerant circuit 6. The outdoor unit 2 includes, mainly, an accumulator 7, a compressor 8, a four-way switching valve 10, an outdoor heat exchanger 11, an outdoor expansion valve 12 as an expansion mechanism, a liquid-side shutoff valve 13, a gas-side shutoff valve 14, an outdoor fan 15, and a casing 40.

The accumulator 7 is a container for supplying a gas refrigerant to the compressor and is disposed on the suction side of the compressor 8.

The compressor 8 sucks and compresses a low-pressure gas refrigerant and discharges a high-pressure gas refrigerant.

The outdoor heat exchanger 11 is a heat exchanger that functions during a cooling operation as a radiator for refrigerant that is discharged from the compressor 8 and that functions during a heating operation as an evaporator for refrigerant that is sent from an indoor heat exchanger 51. The outdoor heat exchanger 11 is connected at the liquid side thereof to the outdoor expansion valve 12 and connected at the gas side thereof to the four-way switching valve 10.

The outdoor expansion valve 12 is an electric expansion valve capable of, during a cooling operation, decompressing refrigerant whose heat is radiated in the outdoor heat exchanger 11 before sending the refrigerant to the indoor heat exchanger 51 and, during a heating operation, decompressing refrigerant whose heat is radiated in the indoor heat exchanger 51 before sending the refrigerant to the outdoor heat exchanger 11.

One end of the liquid-refrigerant connection pipe 4 is connected to the liquid-side shutoff valve 13 of the outdoor unit 2. One end of the gas-refrigerant connection pipe 5 is connected to the gas-side shutoff valve 14 of the outdoor unit 2.

Devices of the outdoor unit 2 and the valves are connected to each other by refrigerant pipes 16 to 22.

The four-way switching valve 10 switches between a connection state for a cooling operation and a connection state for a heating operation, which are to be described later, by switching between a state (see the solid lines in the four-way switching valve 10 in FIG. 1) in which the discharge side of the compressor 8 is connected to the side of the outdoor heat exchanger 11 and in which the suction side of the compressor 8 is connected to the side of the gas-side shutoff valve 14 and a state (see the dashed lines in the four-way switching valve 10 in FIG. 1) in which the discharge side of the compressor 8 is connected to the side of the gas-side shutoff valve 14 and in which the suction side of the compressor 8 is connected to the side of the outdoor heat exchanger 11.

The outdoor fan 15 is disposed in an inner portion of the outdoor unit 2 and, after taking outdoor air therein and supplying the outdoor air to the outdoor heat exchanger 11, forms an airflow (indicated by arrows in FIG. 3) that is discharged to the outside of the unit. As above, the outdoor air supplied by the outdoor fan 15 is used as a cooling source or a heating source in a heat exchange with the refrigerant of the outdoor heat exchanger 11.

As illustrated in the perspective view schematically illustrating the external appearance of the outdoor unit 2 in FIG. 2 and in the schematic plan view of the outdoor unit 2 in FIG. 3, the casing 40 includes, mainly, a bottom frame 40a, a top panel 40b, a left front panel 40c, a right front panel 40d, and a right-side panel 40e. The bottom frame 40a is a laterally elongated substantially rectangular plate-shaped member that constitutes the bottom surface portion of the casing 40. The bottom frame 40a is set on a local installation surface via fixed legs 41 fixed to the lower surface of the bottom frame 40a. The top panel 40b is a laterally elongated substantially rectangular plate-shaped member that constitutes the top surface portion of the casing 40. The left front panel 40c is a plate-shaped member that constitutes, mainly, the left front surface portion and the left-side surface portion of the casing 40 and includes two blow-out ports for blowing out, to the front surface side, the air that has been taken into the casing 40 from the back surface side and the left-side surface side by the outdoor fan 15. The blow-out ports are vertically juxtaposed. A fan grille 42 is disposed at each of the blow-out ports. The right front panel 40d is a plate-shaped member that constitutes, mainly, the right front surface portion and the front portion of the right side surface of the casing 40. The right-side panel 40e is a plate-shaped member that constitutes, mainly, the rear portion of the right side surface and the right back surface portion of the casing 40.

In the casing 40, a partition plate 43 that partitions a fan chamber in which the outdoor fan 15 and the like are disposed and a machine chamber in which the compressor 8 and the like are disposed from each other is disposed.

(2-2) Overall Structure of Outdoor Heat Exchanger

FIG. 4 is a perspective view schematically illustrating the external appearance of the outdoor heat exchanger 11.

The outdoor heat exchanger 11 includes, mainly, a gas-side flow divider 23, a liquid-side flow divider 24, a plurality of inflow-side returning members 25, a plurality of opposite-inflow-side returning members 26, a plurality of outdoor flat tubes 90, and a plurality of outdoor fins 91. All of these components that constitute the outdoor heat exchanger 11 are formed of aluminum or an aluminum alloy and joined to each other by brazing or the like.

The plurality of outdoor flat tubes 90 are vertically juxtaposed.

The plurality of outdoor fins 91 are disposed side by side in a plate thickness direction thereof so as to extend along the outdoor flat tubes 90 and are fixed to the plurality of the outdoor flat tubes 90.

The gas-side flow divider 23 is connected to the refrigerant pipe 19 and, of the plurality of the outdoor flat tubes 90, the outdoor flat tubes 90 disposed in an upper portion. When the outdoor heat exchanger 11 functions as a radiator for the refrigerant, the flow of the refrigerant that has flowed from the refrigerant pipe 19 into the outdoor heat exchanger 11 is divided into flows at a plurality of height positions and sent to, of the plurality of outdoor flat tubes 90, the outdoor flat tubes 90 disposed in the upper portion.

The liquid-side flow divider 24 is connected to the refrigerant pipe 20 and, of the plurality of outdoor flat tubes 90, the outdoor flat tubes 90 disposed in a lower portion. When the outdoor heat exchanger 11 functions as a radiator for the refrigerant, the flows of the refrigerant that have flowed from, of the plurality of outdoor flat tubes 90, the outdoor flat tubes 90 disposed in the lower portion are merged together and caused to flow to the outside of the outdoor heat exchanger 11 through the refrigerant pipe 20.

The plurality of inflow-side returning members 25 are disposed between the gas-side flow divider 23 and the liquid-side flow divider 24 and connect ends of the outdoor flat tubes 90 disposed at mutually different height positions to each other.

The opposite-inflow-side returning members 26 are disposed at an end of the outdoor heat exchanger 11 on a side opposite to a side where the gas-side flow divider 23, the liquid-side flow divider 24, and the plurality of inflow-side returning members 25 are disposed. The opposite-inflow-side returning members 26 connect ends of the outdoor flat tubes 90 disposed at mutually different height positions to each other.

As above, by including the plurality of inflow-side returning members 25 and the opposite-inflow-side returning members 26, the outdoor heat exchanger 11 enables the refrigerant to flow while returning at both ends of the outdoor heat exchanger 11.

(2-3) Outdoor Flat Tube

FIG. 5 illustrates a positional relation between the outdoor fins 91 and the outdoor flat tubes 90 viewed, in a state of being sectioned along a section perpendicular to a direction in which flow channels 90c in inner portions of the outdoor flat tubes 90 extend, in the direction in which the flow channels 90c extend.

The outdoor flat tubes 90 each include an upper-side flat surface 90a facing vertically upward and constituting the upper surface, a lower-side flat surface 90b facing vertically downward and constituting the lower surface, and a large number of the flow channels 90c that are small and in which refrigerant flows. The plurality of flow channels 90c included in the outdoor flat tubes 90 are disposed side by side in an airflow direction (indicated by arrows in FIG. 5; the longitudinal direction of the outdoor flat tubes 90 in a sectional view of the flow channels 90c). The plurality of outdoor flat tubes 90 that are used are identical to each other in terms of a height HT in an up-down direction. The height HT denotes a width between the upper-side flat surface 90a and the lower-side flat surface 90b of each outdoor flat tube 90 in the height direction. The plurality of outdoor flat tubes 90 are arranged in the up-down direction at a predetermined pitch (stage pitch DP). The stage pitch DP is an interval between the upper-side flat surfaces 90a of the outdoor flat tubes 90.

The outdoor heat exchanger 11 according to one or more embodiments is configured such that downstream-side ends of the plurality of outdoor flat tubes 90 in the airflow direction are positioned on the downstream side from downstream-side ends of the outdoor fins 91 in the airflow direction. Consequently, the leeward-side ends of the outdoor fins 91 are suppressed from being damaged or broken during manufacture or transport of the outdoor heat exchanger 11.

(2-4) Outdoor Fin

The outdoor fins 91 are plate-shaped members extending in the airflow direction and in the up-down direction. A plurality of the outdoor fins 91 are disposed in the plate thickness direction thereof at predetermined intervals and fixed to the outdoor flat tubes 90.

The outdoor fins 91 each include a plurality of insertion portions 92, an outdoor continuous portion 97a, a plurality of leeward portions 97b, a waffle portion 93, windward-side fin tabs 94a, leeward-side fin tabs 94b, outdoor slits 95, windward-side ribs 96a, leeward-side ribs 96b, and the like. The thickness of each outdoor fin 91 at a flat portion in the plate thickness direction is, for example, 0.05 mm or more and 0.15 mm or less.

Each of the insertion portions 92 is formed by being horizontally cut from the leeward-side edge of the outdoor fin 91 toward the windward side to a portion before the windward-side edge thereof. The plurality of insertion portions 92 are disposed side by side in the up-down direction. The insertion portions 92 constitute a fin collar that is formed by burring or the like. The shape of each of the insertion portions 92 is substantially in coincident with the outer shape of the section of each outdoor flat tube 90. The outdoor flat tubes 90 are fixed to the outdoor fins 91 at the insertion portions 92 by brazing in a state of being inserted into the insertion portions 92.

The outdoor continuous portion 97a is, of each outdoor fin 91, a portion that is continuous in the up-down direction on the further windward side from the windward-side ends of the outdoor flat tubes 90. From the point of view of ensuring frost proof performance, a distance in the airflow direction from the windward ends of the outdoor flat tubes 90 to the windward end of the outdoor continuous portion 97a of each outdoor fin 91 may be 4 mm or more.

The plurality of leeward portions 97b extend from different height positions in the outdoor continuous portion 97a toward the downstream side in the airflow direction. Each leeward portion 97b is surrounded in the up-down direction by the insertion portions 92 adjacent to each other.

The waffle portion 93 is formed, in each outdoor fin 91, in the vicinity of the center in the airflow direction and configured to include a bump part and a non-bump part in the plate thickness direction.

The windward-side fin tabs 94a and the leeward-side fin tabs 94b are disposed in the vicinity of the windward-side ends and in the vicinity of the leeward-side ends, respectively, to restrict the interval between the outdoor fins 91.

Each outdoor slit 95 is a portion that is configured by being cut and raised in the plate thickness direction from a flat part to improve the heat transfer performance of the outdoor fins 91 and is formed on the downstream side of the waffle portion 93 in the airflow direction. Each outdoor slit 95 has a longitudinal direction in the up-down direction (the arrangement direction of the outdoor flat tubes 90). A plurality (two shown in FIG. 5) of the outdoor slits 95 are disposed side by side in the airflow direction. These outdoor slits 95 are cut and raised from the flat part on the same side in the plate thickness direction, thereby having openings on the upstream side and the downstream side in the airflow direction, respectively.

The windward-side ribs 96a are disposed above and below the windward-side fin tabs 94a to extend in the airflow direction between mutually vertically adjacent outdoor flat tubes 90. The leeward-side ribs 96b continue from the leeward-side ends of the windward-side ribs 96a and extend further on the leeward side.

(3) Indoor Unit

(3-1) General Configuration of Indoor Unit

FIG. 6 is a perspective view of the external appearance of the indoor unit 3. FIG. 7 is a schematic plan view of the indoor unit 3 with the top panel thereof removed. FIG. 8 is a schematic side sectional view of the indoor unit 3 along a section indicated by A-A in FIG. 7.

In one or more embodiments, the indoor unit 3 is an indoor unit of a type that is installed on a ceiling of a room or the like that is an air-conditioning target space by being embedded in an opening of the ceiling. The indoor unit 3 constitutes a portion of the refrigerant circuit 6. The indoor unit 3 includes, mainly, the indoor heat exchanger 51, an indoor fan 52, a casing 30, a flap 39, a bell mouth 33, and a drain pan 32.

The indoor heat exchanger 51 is a heat exchanger that functions, during a cooling operation, as an evaporator for the refrigerant sent from the indoor heat exchanger 51 and functions, during a heating operation, as a radiator for the refrigerant discharged from the compressor 8. The indoor heat exchanger 51 is connected at the liquid side thereof to the indoor-side end of the liquid-refrigerant connection pipe 4 and connected at the gas side thereof to the indoor-side end of the gas-refrigerant connection pipe 5.

The indoor fan 52 is a centrifugal fan disposed in an inner portion of a casing body 31 of the indoor unit 3. The indoor fan 52 takes indoor air through an intake port 36 of a decorative panel 35 into the casing 30 and, after causing the air to pass through the indoor heat exchanger 51, forms an airflow (indicated by arrows in FIG. 8) that blows out to the outside of the casing 30 through a blow-out port 37 of the decorative panel 35. The indoor air thus supplied by the indoor fan 52 exchanges heat with the refrigerant of the indoor heat exchanger 51, and the temperature of the indoor air is thereby controlled.

The casing 30 includes, mainly, the casing body 31 and the decorative panel 35.

The casing body 31 is disposed to be inserted into an opening formed in a ceiling U of an air-conditioned room. In plan view, the casing body 31 is a substantially octagonal box-shaped body having long sides and short sides alternately formed. The casing body 31 has an open lower surface. The casing body 31 includes a top panel and a plurality of side plates extending downward from the peripheral portion of the top panel.

The decorative panel 35 is disposed to be fitted into the opening of the ceiling U and extends further on the outer side in plan view than the top panel and the side plates of the casing body 31. The decorative panel 35 is mounted below the casing body 31 from the indoor side. The decorative panel 35 includes an inner frame 35a and an outer frame 35b. On the inner side of the inner frame 35a, the intake port 36 opening downward and having a substantially quadrangular shape is formed. A filter 34 for removing dust in air that has been taken in through the intake port 36 is disposed above the intake port 36. In a part that is on the inner side of the outer frame 35b and on the outer side of the inner frame 35a, the blow-out port 37 and a corner blow-out port 38 that open to be directed obliquely downward from the lower portion of the part are formed. The blow-out port 37 includes, in locations corresponding to the sides of the substantially quadrangular shape of the decorative panel 35 in plan view, a first blow-out port 37a, a second blow-out port 37b, a third blow-out port 37c, and a fourth blow-out port 37d. The corner blow-out port 38 includes, in locations corresponding to the four corners of the substantially quadrangular shape of the decorative panel 35 in plan view, a first corner blow-out port 38a, a second corner blow-out port 38b, a third corner blow-out port 38c, and a fourth corner blow-out port 38d.

The flap 39 is a member capable of changing a direction of an airflow that passes through the blow-out port 37. The flap 39 includes a first flap 39a disposed in the first blow-out port 37a, a second flap 39b disposed in the second blow-out port 37b, a third flap 39c disposed in the third blow-out port 37c, and a fourth flap 39d disposed in the fourth blow-out port 37d. Each of the flaps 39a to 39d is rotatably supported in a predetermined location in the casing 30.

The drain pan 32 is disposed on the lower side of the indoor heat exchanger 51 and receives drain water that is generated as a result of moisture in air condensing in the indoor heat exchanger 51. The drain pan 32 is mounted in a lower portion of the casing body 31. The drain pan 32 includes a cylindrical space extending in the up-down direction on the inner side of the indoor heat exchanger 51 in plan view. The bell mouth 33 is disposed in an inner lower portion of the space. The bell mouth 33 guides the air that is taken in through the intake port 36 to the indoor fan 52. The drain pan 32 includes a plurality of blow-out flow channels 47a to 47d and corner blow-out flow channels 48a to 48c that extend in the up-down direction on the outer side of the indoor heat exchanger 51 in plan view. The blow-out flow channels 47a to 47d include a first blow-out flow channel 47a in communication at the lower end thereof with the first blow-out port 37a, a second blow-out flow channel 47b in communication at the lower end thereof with the second blow-out port 37b, a third blow-out flow channel 47c in communication at the lower end thereof with the third blow-out port 37c, and a fourth blow-out flow channel 47d in communication at the lower end thereof with the fourth blow-out port 37d. The corner blow-out flow channels 48a to 48c include a first corner blow-out flow channel 48a in communication at the lower end thereof with the first corner blow-out port 38a, a second corner blow-out flow channel 48b in communication at the lower end thereof with the second corner blow-out port 38b, and a third corner blow-out flow channel 48c in communication at the lower end thereof with the third corner blow-out port 38c.

(3-2) Overall Structure of Indoor Heat Exchanger

FIG. 9 is a perspective view schematically illustrating the external appearance of the indoor heat exchanger 51. FIG. 10 is a partially enlarged perspective view of the external appearance of the indoor heat exchanger 51 on the windward side of a plurality of indoor fins 60.

The indoor heat exchanger 51 is disposed, in an inner portion of the casing body 31, at a height position identical to the height position of the indoor fan 52 in a state of being bent to surround the periphery of the indoor fan 52. The indoor heat exchanger 51 includes, mainly, a liquid-side header 81, a gas-side header 71, a return header 59, a plurality of indoor flat tubes 55, and a plurality of the indoor fins 60. All of these components that constitute the indoor heat exchanger 51 are formed of aluminum or an aluminum alloy and joined to each other by brazing or the like.

The indoor heat exchanger 51 includes a windward heat exchanging section 70 (inner part in plan view) that constitutes the windward side thereof in the airflow direction, and a leeward heat exchanging section 80 (outer part in plan view) that constitutes the leeward side thereof in the airflow direction.

The liquid-side header 81 constitutes, of the indoor heat exchanger 51, one end of the leeward heat exchanging section 80 in plan view and is a cylindrical member extending in the up-down direction. An indoor-side end of the liquid-refrigerant connection pipe 4 is connected to the liquid-side header 81. A plurality of the indoor flat tubes 55 that constitute, of the indoor heat exchanger 51, the leeward heat exchanging section 80 are connected to the liquid-side header 81 so as to be disposed side by side vertically.

The gas-side header 71 constitutes, of the indoor heat exchanger 51, one end of the windward heat exchanging section 70 in plan view and is a cylindrical member extending in the up-down direction. The indoor-side end of the gas-refrigerant connection pipe 5 is connected to the gas-side header 71. A plurality of the indoor flat tubes 55 that constitute, of the indoor heat exchanger 51, the windward heat exchanging section 70 are connected to the gas-side header 71 so as to be disposed side by side vertically.

The return header 59 constitutes, of the indoor heat exchanger 51, an end on a side opposite to the side where the liquid-side header 81 and the gas-side header 71 are disposed in plan view and includes a plurality of return spaces disposed side by side in an inner portion thereof in the up-down direction. The indoor flat tubes 55 constituting the windward heat exchanging section 70 and the indoor flat tubes 55 constituting the leeward heat exchanging section 80 are connected to the return spaces disposed at height positions identical to respective height positions of the indoor flat tubes 55. Consequently, the return header 59 enables, while suppressing the refrigerants that have flowed through the indoor flat tubes 55 at different height positions from mixing together, the refrigerants that have flowed through the indoor flat tubes 55 at respective height positions to return to be sent to the indoor flat tubes 55 at height positions identical to the height positions thereof on the windward side (when the indoor heat exchanger 51 function as the evaporator for the refrigerant) or on the leeward side (when the indoor heat exchanger 51 functions as the radiator for the refrigerant).

The plurality of indoor flat tubes 55 include indoor flat tubes that constitute the windward heat exchanging section 70 and indoor flat tubes that constitute the leeward heat exchanging section 80. In other words, the plurality of indoor flat tubes 55 include indoor flat tubes that are juxtaposed in the up-down direction in the windward heat exchanging section 70 of the indoor heat exchanger 51 and indoor flat tubes that are juxtaposed in the up-down direction in the leeward heat exchanging section 80 of the indoor heat exchanger 51. The plurality of indoor flat tubes 55 constituting the windward heat exchanging section 70 are each connected at one end thereof to the gas-side header 71 and connected at the other end thereof to the windward-side part of the return header 59. The plurality of the indoor flat tubes 55 constituting the leeward heat exchanging section 80 are each connected at one end thereof to the liquid-side header 81 and connected at the other end thereof to the leeward-side part of the return header 59.

Similarly, the plurality of indoor fins 60 include indoor fins that constitute the windward heat exchanging section 70 and indoor fins that constitute the leeward heat exchanging section 80. In other words, the plurality of indoor fins 60 include indoor fins that are fixed to the indoor flat tubes 55 that constitute the windward heat exchanging section 70 of the indoor heat exchanger 51, and indoor fins that are fixed to the indoor flat tubes 55 that constitute the leeward heat exchanging section 80 of the indoor heat exchanger 51. The indoor fins 60 are disposed side by side in the plate thickness direction of the indoor fins 60 such that each indoor fin 60 extends along the indoor flat tubes 55.

(3-3) Indoor Flat Tube

FIG. 11 illustrates a positional relation between the indoor fins 60 and the indoor flat tubes 55 viewed, in a state of being sectioned along a section perpendicular to a direction in which flow channels 55c in the inner portions of the indoor flat tubes 55 extend, in the direction in which the flow channels 55c extend.

The indoor flat tubes 55 each include an upper-side flat surface 55a facing vertically upward and constituting the upper surface, a lower-side flat surface 55b facing vertically downward and constituting the lower surface, and a large number of the flow channels 55c that are small and in which refrigerant flows. The plurality of flow channels 55c included in the indoor flat tubes 55 are disposed side by side in an airflow direction (indicated by arrows in FIG. 11; the longitudinal direction of the indoor flat tubes 55 in a sectional view of the flow channels 55c). The plurality of indoor flat tubes 55 that are identical to each other in terms of the height HT in the up-down direction are used. The height HT denotes a width between the upper-side flat surface 55a and the lower-side flat surfaces 55b of the indoor flat tubes 55 in the height direction. The height HT may be 1.2 mm or more and 2.5 mm or less. The plurality of indoor flat tubes 55 are arranged at a predetermined pitch (stage pitch DP) in the up-down direction similarly both in the windward heat exchanging section 70 and in the leeward heat exchanging section 80. The stage pitch DP is an interval between the upper-side flat surfaces 55a of the indoor flat tubes 55 and may be 8.0 mm or more and 15.0 mm or less. The indoor heat exchanger 51 satisfies the relation of 4.0≤DP/HT≤10.0. The lower limit of DP/HT of the indoor heat exchanger 51 may be 4.6 or more. The upper limit of DP/HT of the indoor heat exchanger 51 may be 8.0 or less. The indoor heat exchanger 51 may satisfy the relation of 4.6≤DP/HT≤8.0.

The air conditioning apparatus 1 according to one or more embodiments satisfies a relation in which the value of DP/HT of the indoor heat exchanger 51 is smaller than the value of DP/HT of the aforementioned outdoor heat exchanger 11.

In one or more embodiments, the indoor flat tubes 55 constituting the windward heat exchanging section 70 and the indoor flat tubes 55 constituting the leeward heat exchanging section 80 are disposed to be superposed on each other at respective height positions when viewed in the airflow direction.

In the indoor heat exchanger 51 according to one or more embodiments, the upstream-side ends of the plurality of indoor flat tubes 55 in the airflow direction and the upstream-side ends of the indoor fins 60 in the airflow direction are disposed at substantially identical positions in the airflow direction.

(3-4) Indoor Fin

The indoor fins 60 are plate-shaped members extending in the airflow direction and the up-down direction. A plurality of the indoor fins 60 are disposed in the plate thickness direction thereof at predetermined intervals and fixed to the indoor flat tubes 55. In one or more embodiments, the indoor fins 60 constituting the windward heat exchanging section 70 and the indoor fins 60 constituting the leeward heat exchanging section 80 are disposed to be substantially superposed on each other when viewed in the airflow direction. The leeward-side ends of the indoor fins 60 constituting the windward heat exchanging section 70 and the windward-side ends of the indoor fins 60 constituting the leeward heat exchanging section 80 are disposed in contact with each other at least at a portion thereof.

Each of the indoor fins 60 constituting the windward heat exchanging section 70 and each of the indoor fins 60 constituting the leeward heat exchanging section 80 both similarly include a major surface 61, a plurality of fin collar portions 65a, an indoor continuous portion 64, a plurality of windward portions 65, main slits 62, continuous-location slits 63, and the like. The thickness of the flat major surface 61 of each of the indoor fins 60 in the plate thickness direction is, for example, 0.05 mm or more and 0.15 mm or less. The pitch (the interval between the surfaces of mutually adjacent indoor fins 60 on the same side) of the plurality of indoor fins 60 in the plate thickness direction may be 1.0 mm or more and 1.6 mm or less.

The major surface 61 constitutes, of the indoor fins 60, a flat part in which the fin collar portions 65a, the main slits 62, and the continuous-location slits 63 are not disposed.

The fin collar portions 65a are formed to extend horizontally from the windward-side edges of the indoor fins 60 toward the leeward side to a portion before the leeward-side edge. The plurality of fin collar portions 65a are disposed side by side in the up-down direction. The fin collar portions 65a are formed by burring or the like. The contour shape of each fin collar portion 65a is substantially in coincident with the outer shape of the section of each indoor flat tube 55. The indoor flat tubes 55 are fixed to the indoor fins 60 at the fin collar portions 65a by brazing in a state of being inserted into the fin collar portions 65a. FIG. 12 is an illustration of a joined state between the indoor fins 60 and the indoor flat tubes 55 in a section of the flow channels 55c of the indoor flat tubes 55 taken in refrigerant passing direction along a face including a vertical direction. As illustrated in FIG. 12, the fin collar portions 65a are configured by being raised with respect to the major surfaces 61 in the plate thickness direction of the major surfaces 61 on a side opposite the side where the main slits 62 are cut and raised. On a side opposite the side of the major surfaces 61 of the fin collar portions 65a, positioning portions 65x that are bent to extend in a direction away from the upper-side flat surfaces 55a (or the lower-side flat surfaces 55b) of the indoor flat tubes 55 corresponding thereto are disposed. The positioning portions 65x are in surface contact with the major surfaces 61 of the indoor fins 60 adjacent thereto, thereby regulating the interval between the indoor fins 60 in the plate thickness direction. As illustrated in FIG. 12, the fin collar portions 65a are joined by brazing with brazing materials 58 interposed between the fin collar portions 65a and the upper-side flat surfaces 55a (or the lower-side flat surfaces 55b) of the indoor flat tubes 55. A distance DS between a portion where raising of the fin collar portions 65a with respect to the major surfaces 61 starts and a portion where raising of the main slits 62 starts, as illustrated in FIG. 12, on the side of the lower-side flat surfaces 55b of the indoor flat tubes 55 may be 1 mm or less but is not limited thereto. Dew condensation water on the lower-side flat surfaces 55b of the indoor flat tubes 55 is guided to move downward via the portion where the raising of the main slits 62 starts and drained. Therefore, setting the distance DS to a short distance of 1 mm or less enables the dew condensation water to be suppressed from continuing to remain on the lower-side flat surfaces 55b of the indoor flat tubes 55.

The indoor continuous portion 64 is, of each indoor fin 60, a portion continuous in the up-down direction on the further leeward side from the leeward-side ends of the indoor flat tubes 55. The relation between a width WL of the indoor continuous portion 64 of each indoor fin 60 in the airflow direction and a width WF of each indoor fin 60 in the airflow direction may satisfy the relation of 0.2≤WL/WF≤0.5.

The plurality of windward portions 65 extend from different height positions in the indoor continuous portion 64 toward the upstream side in the airflow direction. Each of the windward portions 65 is surrounded in the up-down direction by the fin collar portions 65a adjacent to each other. The length of each windward portion 65 in the up-down direction is defined by DP—HT.

The main slits 62 are portions that are configured by being cut and raised in the plate thickness direction from the flat major surfaces 61 to improve the heat transfer performance of the indoor fins 60. The main slits 62 are formed in the windward portions 65 of the indoor fins 60. A plurality (four shown in FIG. 11) of the main slits 62 are formed side by side in the airflow direction.

The continuous-location slits 63 are also portions that are configured by being cut and raised in the plate thickness direction from the flat major surfaces 61 to improve the heat transfer performance of the indoor fins 60. The continuous-location slits 63 are formed at a plurality of height positions in the indoor continuous portions 64 of the indoor fins 60. The continuous-location slits 63 are disposed so as to each correspond to the downstream side in the airflow direction of the main slits 62 disposed at respective height positions. The continuous-location slits 63 are formed such that the longitudinal direction thereof is the up-down direction. The continuous-location slits 63 are each elongated in the up-down direction such that the upper end thereof extends to a position higher than the upper ends of the main slits 62 corresponding thereto and such that the lower end thereof extends to a position lower than the lower ends of the main slits 62 corresponding thereto.

The main slits 62 and the continuous-location slits 63 are cut and raised from the flat major surfaces 61 on the same side in the plate thickness direction, thereby having openings on the upstream side and the downstream side in the airflow direction, respectively.

(4) Operation of Air Conditioning Apparatus

Next, with reference to FIG. 1, the operation of the air conditioning apparatus 1 will be described. The air conditioning apparatus 1 performs a cooling operation in which refrigerant flows through the compressor 8, the outdoor heat exchanger 11, the outdoor expansion valve 12, and the indoor heat exchanger 51 in this order and a heating operation in which the refrigerant flows through the compressor 8, the indoor heat exchanger 51, the outdoor expansion valve 12, and the outdoor heat exchanger 11 in this order.

(4-1) Cooling Operation

During a cooling operation, the connection state of the four-way switching valve 10 is switched to cause the outdoor heat exchanger 11 to function as the radiator for the refrigerant and the indoor heat exchanger 51 to function as the evaporator for the refrigerant (see the solid lines in FIG. 1). In the refrigerant circuit 6, a low-pressure gas refrigerant of the refrigeration cycle is sucked by the compressor 8 and discharged after being compressed to a high pressure of the refrigeration cycle. The high-pressure gas refrigerant discharged from the compressor 8 is sent to the outdoor heat exchanger 11 through the four-way switching valve 10. The high-pressure gas refrigerant sent to the outdoor heat exchanger 11 radiates heat by, in the outdoor heat exchanger 11 that functions as the radiator for the refrigerant, exchanging the heat with outdoor air supplied as a cooling source by the outdoor fan 15, thereby becoming a high-pressure liquid refrigerant. The high-pressure liquid refrigerant is decompressed to a low pressure of the refrigeration cycle when passing through the outdoor expansion valve 12, thereby becoming refrigerant in a gas-liquid two-phase state. The refrigerant in the gas-liquid two-phase state is sent to the indoor unit 3 through the liquid-side shutoff valve 13 and the liquid-refrigerant connection pipe 4.

The low-pressure refrigerant in the gas-liquid two-phase state evaporates by, in the indoor heat exchanger 51, exchanging heat with indoor air supplied as a heating source by the indoor fan 52 during a cooling operation. Consequently, the air that passes through the indoor heat exchanger 51 is cooled, and cooling of the inside of a room is performed. In this case, the moisture contained in the air that passes through the indoor heat exchanger 51 condenses and thereby generates dew condensation water on the surface of the indoor heat exchanger 51. The low-pressure gas refrigerant that has evaporated in the indoor heat exchanger 51 is sent to the outdoor unit 2 through the gas-refrigerant connection pipe 5.

The low-pressure gas refrigerant sent to the outdoor unit 2 is sucked again by the compressor 8 through the gas-side shutoff valve 14, four-way switching valve 10, and an accumulator 7. During a cooling operation, the refrigerant circulates in the refrigerant circuit 6 as described above.

(4-2) Heating Operation

During a heating operation, the connection state of the four-way switching valve 10 is switched to cause the outdoor heat exchanger 11 to function as the evaporator for the refrigerant and the indoor heat exchanger 51 to function as the radiator for the refrigerant (see the dashed lines of FIG. 1). In the refrigerant circuit 6, a low-pressure gas refrigerant of the refrigeration cycle is sucked by the compressor 8 and discharged after being compressed to a high pressure of the refrigeration cycle. The high-pressure gas refrigerant discharged from the compressor 8 is sent to the indoor unit 3 through the four-way switching valve 10, the gas-side shutoff valve 14, and the gas-refrigerant connection pipe 5.

The high-pressure gas refrigerant radiates heat by, in the indoor heat exchanger 51, exchanging the heat with indoor air supplied as a cooling source by the indoor fan 52 and becomes a high-pressure liquid refrigerant. Consequently, the air that passes through the indoor heat exchanger 51 is heated, and heating of the inside of a room is performed. The high-pressure liquid refrigerant that has radiated heat in the indoor heat exchanger 51 is sent to the outdoor unit 2 through the liquid-refrigerant connection pipe 4.

The high-pressure liquid refrigerant sent to the outdoor unit 2 is decompressed to a low pressure of the refrigeration cycle in the outdoor expansion valve 12 through the liquid-side shutoff valve 13 and becomes a low-pressure refrigerant in a gas-liquid two-phase state. The low-pressure refrigerant in the gas-liquid two-phase state decompressed in the outdoor expansion valve 12 evaporates by, in the outdoor heat exchanger 11 that functions as the evaporator for the refrigerant, exchanging heat with outdoor air supplied as a heating source by the outdoor fan 15, thereby becoming a low-pressure gas refrigerant. The low-pressure gas refrigerant is sucked again by the compressor 8 through the four-way switching valve 10 and the accumulator 7. During a heating operation, the refrigerant circulates in the refrigerant circuit 6 as described above.

(5) Features

(5-1)

Generally, the heat transfer rate of indoor fins of an indoor heat exchanger can be increased as the interval at which indoor flat tubes are disposed is decreased. Decreasing the interval at which the indoor flat tubes are disposed, however, increases the flow rate of airflow that passes between the indoor flat tubes and causes dew condensation water to easily disperse. When the height of each indoor flat tube in the up-down direction is large, the flow rate of the airflow that passes between the indoor flat tubes is similarly increased and causes dew condensation water to easily disperse. When the interval at which the indoor flat tubes are disposed is increased, the heat transfer rate of the indoor fins decreases. Consequently, the evaporation temperature of the refrigerant in the indoor heat exchanger is required to be decreased, which generates environment in which dew condensation water is easily generated.

In contrast, the indoor heat exchanger 51 according to one or more embodiments and the air conditioning apparatus 1 that includes the indoor heat exchanger 51 employ the indoor heat exchanger and the air conditioning apparatus that satisfy the relation of 4.0≤DP/HT≤10.0 where HT represents the height of each indoor flat tube 55 in the up-down direction and DP represents the pitch of the plurality of indoor flat tubes 55 in the up-down direction. It is revealed from analysis data in which the values of DP and HT are varied that thus the value of DP/HT of the indoor heat exchanger 51 may be set to be in the numerical range for suppression of dew condensation water.

In other words, thus setting the value of DP/HT of the indoor heat exchanger 51 to 4.0 or more suppresses the flow rate of the airflow that flows to cross the indoor fins 60 from being increased excessively. Consequently, even when the indoor fan 52 is used with the air volume thereof increased, it is possible to suppress dew condensation water from dispersing from the leeward-side end due to the airflow being large.

Moreover, setting the value of DP/HT of the indoor heat exchanger 51 to 10.0 or less causes, of the region in the indoor fins 60, a region far away from the indoor flat tubes 55 to be small and can improve the heat transfer rate of the indoor fins 60. Therefore, the need to decrease the evaporation temperature of the refrigerant of the indoor heat exchanger 51 to ensure the capacity thereof is suppressed. Thus, by causing dew condensation water not to be generated easily, it is enabled to suppress dispersion of dew condensation water from the indoor fins 60, even when the indoor fan 52 is used with the air volume thereof increased.

When the indoor heat exchanger 51 is configured to satisfy the relation of 4.6≤DP/HT≤8.0, it is enabled to make the effect of suppressing the dispersion of dew condensation water more remarkable.

(5-2)

Generally, in an outdoor heat exchanger used in an outdoor unit of an air conditioning apparatus, air flow resistance is easily increased by frost formation on outdoor fins when the outdoor heat exchanger functions as an evaporator for refrigerant. Thus, the pitch of outdoor flat tubes is required to be wide. If a heat exchanger having a structure identical to the structure of such an outdoor heat exchanger that has a structure in which the pitch of flat tubes is wide is applied to an indoor heat exchanger, the heat transfer rate of indoor fins decreases due to the wide pitch of the flat tubes, which requires a decrease in the evaporation temperature of refrigerant in the indoor heat exchanger and causes dew condensation water to be easily generated.

In contrast, the indoor heat exchanger 51 according to one or more embodiments and the air conditioning apparatus 1 that includes the indoor heat exchanger 51 satisfy a relation in which the value of DP/HT of the indoor heat exchanger 51 is smaller than the value of DP/HT of the outdoor heat exchanger 11 where HT represents the height of each of the flat tubes 90 and 55 in the up-down direction and DP represents the pitch of the plurality of flat tubes 90 and 55 in the up-down direction.

Therefore, the heat transfer rate of the indoor fins 60 is improved in the indoor heat exchanger 51, in which dispersion of dew condensation water easily occurs, while frost formation on the outdoor heat exchanger 11, in which dispersion of dew condensation water does not easily occur, when the outdoor heat exchanger 11 is used as the evaporator is suppressed, thereby suppressing the need to decrease the evaporation temperature of the refrigerant of the indoor heat exchanger 51 when the indoor heat exchanger 51 is used as the evaporator and causing dew condensation water not to be easily generated. Consequently, it is enabled to suppress dispersion of dew condensation water.

(5-3)

The indoor heat exchanger 51 according to one or more embodiments includes the windward heat exchanging section 70 and the leeward heat exchanging section 80 and employs a structure in which at least two rows or more of the indoor flat tubes 55 are disposed.

Consequently, of the dew condensation water that is generated on the indoor heat exchanger 51, dew condensation water that has been generated on the windward heat exchanging section 70 is easily guided to move downward on a portion between the windward heat exchanging section 70 and the leeward heat exchanging section 80 or on the leeward heat exchanging section 80 and is to be drained. In addition, air whose dry degree is increased by generating dew condensation water on the windward heat exchanging section 70 when passing through the windward heat exchanging section 70 is supplied to the leeward heat exchanging section 80. It is thus possible to cause the volume of the dew condensation water that is generated on the leeward heat exchanging section 80 to be small and to suppress dispersion of dew condensation water from the leeward-side end of the leeward heat exchanging section 80.

(5-4)

In the indoor heat exchanger 51 according to one or more embodiments, the indoor fins 60 each include the indoor continuous portion 64 on the leeward side of the indoor flat tubes 55. Thus, dew condensation water that has been generated on the indoor flat tubes 55 is easily drained by being guided to move downward on the indoor continuous portions 64 of the indoor fins 60 positioned along the downstream side in the airflow direction. Consequently, it is enabled to suppress dispersion of dew condensation water from the downstream-side ends of the indoor fins 60 in the airflow direction.

In particular, in the indoor heat exchanger 51 according to one or more embodiments, the structure in which the two rows or more of the indoor flat tubes 55 are disposed includes the indoor continuous portions 64 on the downstream side of the indoor fins 60 of the leeward heat exchanging section 80. It is thus enabled to increase drainage of generated dew condensation water while suppressing generation of dew condensation water on the downstream-side ends of the indoor fins 60.

(5-5)

The indoor heat exchanger 51 according to one or more embodiments satisfies the relation of 0.2≤WL/WF≤0.5 where WF represents the length of each indoor fin 60 in the airflow direction and WL represents the length of each indoor continuous portion 64 in the airflow direction. By thus setting the value of WL/WF to 0.2 or more in the indoor fins 60, the width of each indoor continuous portion 64 in the airflow direction is sufficiently ensured, and the dew condensation water that has been generated on the indoor heat exchanger 51 is caused to be easily drained downward through the indoor continuous portions 64. In addition, by setting the value of WL/WF to 0.5 or less in the indoor fins 60, of the region in the indoor fins 60, a region that is far away from the indoor flat tubes 55 and that does not easily contribute to the improvement of the heat transfer performance is caused to be small, and it is thereby enabled to suppress material costs while maintaining the performance of the indoor fins 60.

In particular, by setting the value of WL/WF of the indoor fins 60 to 0.2 or more while positioning the indoor continuous portions 64 of the indoor fins 60 on the downstream side in the airflow direction of the indoor flat tubes 55, it is enabled to increase drainage of the dew condensation water that has been generated on the indoor flat tubes 55 through the indoor continuous portions 64.

(5-6)

The indoor heat exchanger 51 according to one or more embodiments have, in each indoor fin 60, the main slits 62 and the continuous-location slits 63 that are cut and raised to open in the airflow direction. Consequently, the air supplied to the indoor heat exchanger 51 is enabled to come into contact with the indoor fins 60 sufficiently. It is thus enabled to fully utilize an air heat source.

The upper ends of the main slits 62 and the continuous-location slits 63 are disposed to be positioned close to the lower parts of the indoor flat tubes 55 that are positioned directly above. The dew condensation water that has been generated on the indoor flat tubes 55 positioned directly above is thus easily caught and guided to move downward, which enables an enhancement of drainage. In particular, by designing as illustrated in FIG. 12 such that the distance DS between the portion where raising of the fin collar portions 65a with respect to the major surfaces 61 of the indoor fins 60 starts and the portion where raising of the main slits 62 of the indoor fins 60 starts on the side of the lower-side flat surfaces 55b of the indoor flat tubes 55 is 1 mm or less, it is possible to suppress the dew condensation water from remaining on the side of the lower-side flat surfaces 55b of the indoor flat tubes 55 and to enhance drainage performance.

(6) Modification

(6-1) Modification A

The aforementioned embodiments have been described by presenting an example in which the downstream-side end of each indoor fin 60 has a flat shape.

The shape of the downstream-side end of each indoor fin 60 is, however, not limited thereto. For example, the indoor fins 60a that each include a water-guiding rib 99 extending along the downstream-side end in the airflow direction, as described below, may be used.

In FIG. 13, the positional relation between the indoor fins 60a and the indoor flat tubes 55 is illustrated. In FIG. 14, the water-guiding rib 99 along, of the B-B section of FIG. 13, a portion in the vicinity of the downstream side in the airflow direction is illustrated.

As with the aforementioned embodiments, the indoor heat exchanger 51 according to the modification A also includes the windward heat exchanging section 70 and the leeward heat exchanging section 80. Each of the indoor fins 60a of the windward heat exchanging section 70 and the leeward heat exchanging section 80 has the water-guiding rib 99 extending vertically along the downstream-side end in the airflow direction of the indoor continuous portion 64 disposed on the downstream side in the airflow direction. As illustrated in FIG. 14, the water-guiding rib 99 is formed to be recessed in the plate thickness direction of each indoor fin 60a with respect to the major surface 61 around the water-guiding rib 99. Each water-guiding rib 99 may be recessed more than the plate thickness of each indoor fin 60a but not limited thereto.

Thus disposing the water-guiding ribs 99 in the indoor fins 60a causes the dew condensation water that has been generated on the indoor heat exchanger 51 to be caught in the water-guiding ribs 99 and causes the dew condensation water to be easily guided to move downward along the water-guiding ribs 99. Consequently, the dew condensation water is suppressed from reaching the leeward-side ends of the indoor fins 60a, which enables dispersion of the dew condensation water to be sufficiently suppressed.

Each water-guiding rib 99 may be disposed, on the indoor continuous portion 64 of each indoor fin 60a, on the downstream side from the center of the width in the airflow direction. Each water-guiding rib 99 may be disposed in a location having a width within, of the width of the indoor continuous portion 64 in the airflow direction, 20% from the downstream-side end in the airflow direction.

In the indoor fins 60a on each of which the water-guiding rib 99 is disposed, in particular, the relation between the width WL of the indoor continuous portion 64 of each indoor fin 60 in the airflow direction and the width WF of each indoor fin 60 in the airflow direction may satisfy the relation of 0.2≤WL/WF.

(6-2) Modification B

The aforementioned embodiments have been described by presenting an example in which the indoor heat exchanger 51 includes the windward heat exchanging section 70 and the leeward heat exchanging section 80 and in which the indoor flat tubes 55 are juxtaposed in two rows.

The number of the rows along which the indoor flat tubes 55 included in the indoor heat exchanger 51 are disposed side by side in the airflow direction is, however, not limited to two. The rows may be a plurality of rows of three or more. Thus increasing the number of the rows of the indoor flat tubes 55 enables dispersion of the dew condensation water from the downstream-side end of the indoor heat exchanger 51 in the airflow direction to be more effectively suppressed.

(6-3) Modification C

The aforementioned embodiments have been described by presenting an example in which, in the indoor heat exchanger 51, the plurality of indoor flat tubes 55 belonging to the windward heat exchanging section 70 and the plurality of indoor flat tubes 55 belonging to the leeward heat exchanging section 80 are disposed to be superposed on each other when viewed in the airflow direction.

The indoor heat exchanger 51 is, however, not limited thereto. The plurality of indoor flat tubes 55 belonging to the heat exchanging section on the further windward side and the plurality of indoor flat tubes 55 belonging to the heat exchanging section on the further leeward side may be disposed not to be superposed on each other when viewed in the airflow direction. Consequently, both the indoor flat tubes 55 positioned on the windward side and the indoor flat tubes 55 positioned on the leeward side are enabled to be subjected to sufficient airflow.

(6-4) Modification D

The aforementioned embodiments have been described by presenting an example in which the indoor fins 60 of the indoor heat exchanger 51 include the main slits 62 and the continuous-location slits 63 that are configured by being cut and raised such that the entirety of slit pieces is positioned on one side in the plate thickness direction with respect to the major surfaces 61 of the indoor fins 60.

The cut-and-raised portions formed in the indoor fins 60 are, however, not limited thereto. Instead of the main slits 62 and the continuous-location slits 63, for example, the cut and raised slit pieces may employ a structure, called louver, in which the windward-side ends of the slit pieces in the airflow direction are positioned on one side of the major surfaces 61 of the indoor fins 60 in the plate thickness direction and in which the leeward-side ends of the slit pieces in the airflow direction are positioned on the other side of the major surfaces 61 of the indoor fins 60 in the plate thickness direction.

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

REFERENCE SIGNS LIST

• • 1 air conditioning apparatus
  • 2 outdoor unit (outdoor unit)
  • 3 indoor unit (indoor unit)
  • 11 outdoor heat exchanger
  • 51 indoor heat exchanger
  • 55 indoor flat tube (flat tube)
  • 55c flow channel
  • 60 indoor fin (heat transfer fin)
  • 62 main slit (cut-and-raised portion)
  • 63 continuous-location slit (cut-and-raised portion)
  • 64 indoor continuous portion (continuous portion)
  • 65 windward portion (each portion positioned between the flat tubes vertically juxtaposed)
  • 90 outdoor flat tube (flat tube)
  • 90c flow channel
  • 91 outdoor fin (heat transfer fin)
  • 97a continuous portion
  • 97b leeward portion

PATENT LITERATURE

• PTL 1: Japanese Unexamined Patent Application Publication No. 2016-041986

Claims

1.-8. (canceled)

9. An indoor heat exchanger in an indoor unit of an air conditioning apparatus, the indoor heat exchanger comprising:

flat tubes that are juxtaposed in a vertical direction and that each comprise a flow channel that allows refrigerant to pass through an inner portion thereof, and

heat transfer fins joined to the flat tubes and that each comprise: a continuous portion that extends continuously in the vertical direction; and windward portions that are continuous with the continuous portion and are disposed between the flat tubes, wherein

4.0≤DP/HT≤10.0 is satisfied, where HT is a height of each of the flat tubes and DP is a pitch of the flat tubes.

10. An indoor heat exchanger in an indoor unit constituting an air conditioning apparatus together with an outdoor unit that comprises an outdoor heat exchanger, wherein

the outdoor heat exchanger and the indoor heat exchanger each comprise: flat tubes that are juxtaposed in a vertical direction and that each comprise a flow channel that allows refrigerant to pass through an inner portion thereof; and heat transfer fins joined to the flat tubes and that each comprise: a continuous portion that extends continuously in the vertical direction; and windward portions that are continuous with the continuous portion and are disposed between the flat tubes, wherein

a value of DP/HT of the indoor heat exchanger is smaller than a value of DP/HT of the outdoor heat exchanger, where HT is a height of each of the flat tubes and DP is a pitch of the flat tubes.

11. The indoor heat exchanger according to claim 9, wherein the flat tubes each comprise:

upstream-side flat tubes on an upstream side in an airflow direction, and

downstream-side flat tubes on a downstream side of the upstream-side flat tubes in the airflow direction.

12. The indoor heat exchanger according to claim 9, wherein the continuous portion is disposed on a leeward side of the flat tubes in an airflow direction.

13. The indoor heat exchanger according to claim 9, wherein 0.2≤WL/WF≤0.5 is satisfied, where WF is a length of each of the heat transfer fins in an airflow direction and WL is a length of the continuous portion in the airflow direction.

14. The indoor heat exchanger according to claim 9, wherein

the heat transfer fins each comprise a cut-and-raised portion, and

a longitudinal direction of the cut-and-raised portion is the vertical direction.

15. The indoor heat exchanger according to claim 9, wherein 4.6≤DP/HT≤8.0 is satisfied.

16. An air conditioning apparatus comprising:

an indoor unit comprising the indoor heat exchanger according to claim 9, and

an outdoor unit comprising an outdoor heat exchanger.