Patent Description:
A known heat exchanger such as a heat exchanger disclosed in, for example, <CIT> includes heat transfer tubes arranged in three columns adjacent to each other in the direction of air flow and connection pipes each of which branches to form a connection between a heat transfer tube in a column and a heat transfer tube in another column. <CIT>, <CIT>, <CIT>, and <CIT> are further prior art. Document <CIT> discloses a heat exchanger according to the preamble of claims <NUM>, <NUM> and <NUM>.

The heat exchanger includes cylindrical heat transfer tubes to allow passage of refrigerant. However, no mention is made of how to distribute refrigerant among columns of heat transfer tubes in a heat exchanger in which flat tubes having a flat shape are used as heat transfer tubes.

The present invention therefore has been made in view of such circumstances, and it is an object of the present invention to provide a heat exchanger and an air conditioner in which flat tubes having a flat shape may be used as heat transfer tubes in a manner so as to distribute flows of refrigerant appropriately.

The present invention is defined by a heat exchanger according to independent claim <NUM>, a heat exchanger according to independent claim <NUM>, and a heat exchanger according to independent claim <NUM>. Preferred optional embodiments are recited in the dependent claims.

A heat exchanger according to a first aspect is a heat exchanger in which heat is exchanged between refrigerant flowing inside and air flowing outside. The heat exchanger includes at least one upstream-side flat tube, at least two downstream-side flat tubes on a downstream side of the upstream-side flat tube in a direction of air flow, and a space formation member. The space formation member defines distribution space in which the refrigerant coming out of the upstream-side flat tube is distributed to the at least two downstream-side flat tubes.

A feature of the heat exchanger is that the refrigerant coming out of the upstream-side flat tube may be distributed to the downstream-side flat tubes through the distribution space defined by the space formation member. Owing to this feature, flat tubes having a flat shape may be used as heat transfer tubes of the heat exchanger in a manner so as to distribute the refrigerant appropriately.

A heat exchanger according a second aspect is the heat exchanger according to the first aspect, wherein the distribution space is configured to turn back the refrigerant coming out of the upstream-side flat tube and lead to the downstream-side flat tubes.

With the heat exchanger being configured as described above, the refrigerant through the upstream-side flat tube may turn back and may be led to the downstream-side flat tubes when reaching the distribution space.

A heat exchanger according to a third aspect is the heat exchanger according to the first or second aspect and further includes a header. In the header, the distribution space is defined. The space formation member is part of the header. The upstream-side flat tube and the downstream-side flat tubes are connected to the header.

A feature of the heat exchanger is that the upstream-side flat tube and the downstream-side flat tubes are connected to the header in which the distribution space is provided, with the space formation member being part of the header. Owing to this feature, the refrigerant coming out of the upstream-side flat tube may be appropriately distributed to the downstream-side flat tubes.

A heat exchanger according to a fourth aspect is the heat exchanger according to any one of the first to third aspects and is configured to include a portion in which the flat tubes connected to the distribution space do not overlap each other when viewed in the direction of air flow.

The flat tubes may include the upstream-side flat tube and the downstream-side flat tubes.

A feature of the heat exchanger is that the heat exchanger includes a portion in which flat tubes connected to the distribution space do not overlap each other when viewed in the direction of air flow. Owing to this feature, the flat tubes in the relevant part of the heat exchanger may be sufficiently exposed to air.

A heat exchanger according to a fifth aspect is the heat exchanger according to any one of the first to fourth aspects and is configured as follows: the downstream-side flat tubes include at least one first downstream-side flat tube and at least one second downstream-side flat tube on a downstream side of the first downstream-side flat tube in the direction of air flow.

With the heat exchanger being configured as described above, the refrigerant may be appropriately distributed to the first downstream-side flat tube and the second downstream-side flat tube that are in different columns adjacent to each other in the direction of air flow.

A heat exchanger according to a sixth aspect is the heat exchanger according to the fifth aspect, wherein a first communicating channel and a second communicating channel are provided in the distribution space to lead the refrigerant coming out of the upstream-side flat tube to the first downstream-side flat tube and the second downstream-side flat tube, respectively. A flow path defined by the first communicating channel is wider than a flow path defined by the second communicating channel.

A feature of the heat exchanger is that the flow path defined by the first communicating channel that leads the refrigerant coming out of the upstream-side flat tube to the first downstream-side flat tube is wider than the flow path defined by the second communication channel that leads the refrigerant coming out of the upstream-side flat tube to the second downstream-side flat tube. Owing to this feature, the refrigerant coming out of the upstream-side flat tube tends to be led to the first downstream-side flat tube.

A heat exchanger according to a seventh aspect is the heat exchanger according to the fifth aspect, wherein a first communicating channel and a second communicating channel are provided in the distribution space to lead the refrigerant coming out of the upstream-side flat tube to the first downstream-side flat tube and the second downstream-side flat tube, respectively. An inlet of the first communicating channel is located at a position lower than an inlet of the second communicating channel.

A feature of the heat exchanger is that the inlet of the first communicating channel that leads the refrigerant coming out of the upstream-side flat tube to the first downstream-side flat tube is located at a position lower than the inlet of the second communication channel that leads the refrigerant coming out of the upstream-side flat tube to the second downstream-side flat tube. Owing to this feature, the gas-liquid two-phase refrigerant coming out of the upstream-side flat tube tends to be led to the first downstream-side flat tube.

A heat exchanger according to an eighth aspect is the heat exchanger according to any one of the fifth to seventh aspects, wherein the distribution space is connected with the second downstream-side flat tube and the first downstream-side flat tube located at a position lower than the second downstream-side flat tube.

The distribution space is preferably formed in such a manner that an upper end and a lower end thereof extend in their respective height positions in the direction of air flow.

A feature of the heat exchanger is that the first downstream-side flat tube is in a height position lower than the height position of the second downstream-side flat tube and is disposed on an upstream side in the direction of air flow. Owing to this feature, the gas-liquid two-phase refrigerant coming out of the upstream-side flat tube tends to be led to the first downstream-side flat tube.

A heat exchanger according to a ninth aspect is the heat exchanger according to any one of the fifth to eighth aspects, wherein the at least one upstream-side flat tube includes a plurality of upstream-side flat tubes arranged in such a manner that flat portions of each upstream-side flat tubes face each other. The at least one first downstream-side flat tube includes a plurality of first downstream-side flat tubes arranged in such a manner that flat portions of each first downstream-side flat tubes face each other. The at least one second downstream-side flat tube includes a plurality of second downstream-side flat tubes arranged in such a manner that flat portions of each second downstream-side flat tubes face each other. The at least one distribution space includes a plurality of distribution spaces arranged in a manner so that the distribution spaces are aligned to each other in a direction in which the upstream-side flat tubes are aligned to each other.

A feature of the heat exchanger is that the plurality of distribution spaces are arranged in a manner so that the distribution spaces are aligned to each other in a direction in which the upstream-side flat tubes are aligned to each other. In each distribution space, the refrigerant coming out of the upstream-side flat tube may thus be appropriately distributed to the downstream-side flat tube.

A heat exchanger according to a tenth aspect is the heat exchanger according to any one of the fifth to ninth aspects and is configured as follows. The upstream-side flat tube includes a plurality of upstream-side flat tubes including a first upstream-side flat tube and a second upstream-side flat tube that are arranged in such a manner that flat portions of the first and second upstream-side flat tubes face each other. The distribution space includes a first distribution space provided to lead the refrigerant coming out of the first upstream-side flat tube to the downstream-side flat tubes and a second distribution space provided to lead the refrigerant coming out of the second upstream-side flat tube to the downstream-side flat tubes independently of the first distribution space. In part of the distribution space, the number of the first downstream-side flat tubes connected to the first distribution space is greater than the number of the first downstream-side flat tubes connected to the second distribution space.

The portion in which the number of the first downstream-side flat tubes connected to the first distribution space is greater than the number of the first downstream-side flat tubes connected to the second distribution space may be part of the heat exchanger.

The speed of air flow supplied to the heat exchanger is not constant across the heat exchanger, in which wind speed distribution is found. This may improve the performance of the heat exchanger in use environments where the speed of air flow passing by the first upstream-side flat tube is lower than the speed of air flow passing by the second upstream-side flat tube.

An air conditioner according to an eleventh aspect includes the heat exchanger according to any one the first to tenth aspects and a fan that supplies air flow to the heat exchanger.

Flat tubes having a flat shape may be used as heat transfer tubes of the air conditioner in such a manner that the refrigerant coming out of the upstream-side flat tube is appropriately distributed to the downstream-side flat tubes on a downstream side in the direction of air flow created by the fan.

<FIG> is a schematic configuration diagram of an air conditioner <NUM>.

The air conditioner <NUM> is an apparatus capable of cooling or heating a room in a building or the like through a vapor compression refrigeration cycle.

The air conditioner <NUM> includes mainly an outdoor unit <NUM>, an indoor unit <NUM>, a liquid-refrigerant connection pipe <NUM>, and a gas-refrigerant connection pipe <NUM>. These refrigerant connection pipes are refrigerant paths connecting the outdoor unit <NUM> to the indoor unit <NUM>. The outdoor unit <NUM>, the indoor unit <NUM>, and the refrigerant connection pipes <NUM> and <NUM> forming connections between these units constitute a vapor compression refrigerant circuit <NUM> of the air conditioner <NUM>. The refrigerant connection pipes <NUM> and <NUM> are refrigerant pipes that are to be laid on-site when the air conditioner <NUM> is installed on an installation site such as a building. The refrigerant circuit <NUM> is charged with a working refrigerant, which is R32 in the present embodiment but is not limited to R32.

The outdoor unit <NUM> is installed outdoors (on a rooftop of a building or adjacent to the surface of a wall of a building) and is part of the refrigerant circuit <NUM>. The outdoor unit <NUM> includes mainly an accumulator <NUM>, a compressor <NUM>, a four-way switching valve <NUM>, an outdoor heat exchanger <NUM>, an outdoor expansion valve <NUM> (i.e., an expansion mechanism), a liquid-side shutoff valve <NUM>, a gas-side shutoff valve <NUM>, an outdoor fan <NUM>, and a casing <NUM>.

The accumulator <NUM> is a container for supplying gas refrigerant to a compressor and is provided on the intake side of the compressor <NUM>.

The compressor <NUM> sucks in low-pressure gas refrigerant, compresses the refrigerant to transform it into high-pressure gas refrigerant, and then discharges the gas refrigerant.

The outdoor heat exchanger <NUM> is a heat exchanger that functions as a radiator for refrigerant discharged by the compressor <NUM> during cooling operation and functions as an evaporator for refrigerant transmitted from an indoor heat exchanger <NUM> during heating operation. The liquid side of the outdoor heat exchanger <NUM> is connected to the outdoor expansion valve <NUM>, and the gas side of the outdoor heat exchanger <NUM> is connected to the four-way switching valve <NUM>.

The outdoor expansion valve <NUM> is an electric expansion valve capable of decompressing refrigerant in the following manner: during the cooling operation, refrigerant having transferred heat in the outdoor heat exchanger <NUM> is decompressed before being transmitted to the indoor heat exchanger <NUM>; and during heating operation, refrigerant having transferred heat in the indoor heat exchanger <NUM> is decompressed before being transmitted to the outdoor heat exchanger <NUM>.

The liquid-side shutoff valve <NUM> of the outdoor unit <NUM> is connected with an end of the liquid-refrigerant connection pipe <NUM>. The gas-side shutoff valve <NUM> of the outdoor unit <NUM> is connected with an end of the gas-refrigerant connection pipe <NUM>.

Refrigerant pipes <NUM> to <NUM> form connections between the devices and valves included in the outdoor unit <NUM>.

The four-way switching valve <NUM> switches between a connected state for the cooling operation and a connected state for the heating operation, which will be described later, by switching between the following states: the state in which the discharge side of the compressor <NUM> is connected to the outdoor heat exchanger <NUM> side and the intake side of the compressor <NUM> is connected to the gas-side shutoff valve <NUM> side (see solid lines in the four-way switching valve <NUM> illustrated in <FIG>); and the state in which the discharge side of the compressor <NUM> is connected to the gas-side shutoff valve <NUM> side and the intake side of the compressor <NUM> is connected to the outdoor heat exchanger <NUM> side (see broken lines in the four-way switching valve <NUM> illustrated in <FIG>).

The outdoor fan <NUM> is disposed inside the outdoor unit <NUM> and creates air flow (denoted by arrows in <FIG>) by sucking in outdoor air, which is in turn supplied to the outdoor heat exchanger <NUM> and is then discharged out of the unit. In this way, the outdoor air supplied by the outdoor fan <NUM> is used as a cooling source or a heating source that exchanges heat with refrigerant in the outdoor heat exchanger <NUM>.

As illustrated in <FIG>, which is a schematic external perspective view of the outdoor unit <NUM>, and in <FIG>, which is a schematic configuration diagram of the outdoor unit <NUM> viewed in plan, the casing <NUM> 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 plate-shaped member being a bottom face part of the casing <NUM> and having an oblong, substantially rectangular shape and is placed on an installation surface on-site via fixation legs <NUM> fixed to the underside. The top panel 40b is a plate-shaped member being a top face part of the casing <NUM> and having an oblong, substantially rectangular shape. The left-front panel 40c is a plate-shaped member being mainly a left front face part and a left side face part of the casing <NUM> and is provided with two blow-out openings adjacent to each other in up-and-down directions. Air drawn into the casing <NUM> by the outdoor fan <NUM> through a back face and a left side face is blown on a front face through the blow-out openings. Each blow-out opening is provided with a fan grille <NUM>. The right-front panel 40d is a plate-shaped member being mainly a right front face part of the casing <NUM> and a front portion of a right side face of the casing <NUM>. The right-side panel 40e is a plate-shaped member being mainly a rear portion of the right side face of the casing <NUM> and a right back face part of the casing <NUM>.

The casing <NUM> is provided with a partition plate <NUM>, which is a partition between a fan room in which devices such as the outdoor fan <NUM> are placed and a machine room in which devices such as the compressor <NUM> are placed.

<FIG> is a schematic external perspective view of the outdoor heat exchanger <NUM>.

The outdoor heat exchanger <NUM> includes mainly a gas-side flow divider <NUM>, a liquid-side flow divider <NUM>, inflow-side turnback members <NUM>, anti-inflow-side turnback members <NUM>, outdoor flat tubes <NUM>, and outdoor fins <NUM>. These components of the outdoor heat exchanger <NUM> are all made of aluminum or an aluminum alloy and are bonded to each other, for example, by means of brazing.

The outdoor flat tubes <NUM> are arranged in a manner so as to be adjacent to each other in up-and-down directions.

The outdoor fins <NUM> are arranged side by side in the plate thickness direction thereof in a manner so as to be adjacent to each other along the outdoor flat tubes <NUM> and are fixed to the outdoor flat tubes <NUM>.

The gas-side flow divider <NUM> is connected to a refrigerant pipe <NUM> and to the outdoor flat tubes <NUM> on the upper side. When the outdoor heat exchanger <NUM> functions as a radiator for refrigerant, refrigerant flowing from the refrigerant pipe <NUM> into the outdoor heat exchanger <NUM> is divided into flows of refrigerant in different height positions, and the flows of refrigerant are conducted to the outdoor flat tubes <NUM> on the upper side.

The liquid-side flow divider <NUM> is connected to a refrigerant pipe <NUM> and to the outdoor flat tubes <NUM> on the lower side. When the outdoor heat exchanger <NUM> functions as a radiator for refrigerant, flows of refrigerant from the outdoor flat tubes <NUM> on the lower side are merged to drain out of the outdoor heat exchanger <NUM> through the refrigerant pipe <NUM>.

The inflow-side turnback members <NUM> are disposed between the gas-side flow divider <NUM> and the liquid-side flow divider <NUM>. The inflow-side turnback members <NUM> form connections between end portions of the outdoor flat tubes <NUM> located in different height positions.

The anti-inflow-side turnback members <NUM> are provided to an end portion of the outdoor heat exchanger <NUM>. The end portion is opposite to an end portion to which the gas-side flow divider <NUM>, the liquid-side flow divider <NUM>, and the inflow-side turnback members <NUM> are provided. The anti-inflow-side turnback members <NUM> form connections between end portions of the outdoor flat tubes <NUM> located in different height positions.

The outdoor heat exchanger <NUM> includes the inflow-side turnback members <NUM> and the anti-inflow-side turnback members <NUM> as described above. Owing to this feature, refrigerant flowing through the outdoor heat exchanger <NUM> can turn back at both ends of the outdoor heat exchanger <NUM>.

<FIG> illustrates the positional relationship between the outdoor fin <NUM> and the outdoor flat tubes <NUM> in a sectional view orthogonal to a direction in which flow paths 90c in the outdoor flat tubes <NUM> extend, with the outdoor fin <NUM> and the outdoor flat tubes <NUM> being viewed in the direction in which the flow paths 90c extend.

Each outdoor flat tube <NUM> has: an upper flat surface 90a, which faces vertically upward as an upper face; a lower flat surface 90b, which faces vertically downward as a lower face; a large number of small flow paths 90c, through which refrigerant flows. The flow paths 90c of the outdoor flat tube <NUM> are arranged in a manner so as to be adjacent to each other in the direction of air flow (denoted by arrows in <FIG> and corresponding to the longitudinal direction of the outdoor flat tube <NUM> in the sectional view of the flow paths 90c).

Each outdoor fin <NUM> is a plate-shaped member extending in the direction of air flow and in up-and-down directions. The outdoor fins <NUM> are arranged side by side at predetermined spacings in the plate thickness direction thereof and are fixed to the outdoor flat tubes <NUM>.

Each outdoor fin <NUM> includes, for example, an outdoor communicating portion 97a, leeward portions 97b, waffle portions <NUM>, windward-side fin tabs 94a, leeward-side fin tabs 94b, outdoor slits <NUM>, windward-side ribs 96a, and downstream-side ribs 96b.

The outdoor communicating portion 97a is part of the outdoor fin <NUM> and extends continuously in up-and-down directions on the windward side of windward-side end portions of the outdoor flat tubes <NUM>.

The leeward portions 97b respectively extend from different height positions in the outdoor communicating portion 97a toward the downstream side in the direction of air flow. Each leeward portion 97b is sandwiched between two outdoor flat tubes <NUM> being adjacent to each other in up-and-down directions and respectively lying above and below the leeward portion 97b.

The waffle portions <NUM> are in or close to the middle part of the outdoor fin <NUM> in the direction of air flow, and each waffle portion <NUM> includes protrusive portions protruding in the plate thickness direction and non-protrusive portions.

The windward-side fin tabs 94a are close to windward-side end portions in a manner so as to provide spacing between the individual outdoor fins <NUM>, and the leeward-side fin tabs 94b are close to leeward-side end portions in a manner so as to provide spacing between the individual outdoor fins <NUM>.

The outdoor slits <NUM> are portions cut out and raised in the plate thickness direction from a flat portion and are provided to increase the heat transfer capability of the outdoor fin <NUM>. The outdoor slits <NUM> are formed on the downstream side of the waffle portion <NUM> in the direction of air flow. The outdoor slits <NUM> are formed in such a manner that the longitudinal direction thereof coincides with the up-and-down directions (the direction in which the individual outdoor flat tubes <NUM> are adjacent to each other). A plurality of outdoor slits <NUM> (in the present embodiment, two outdoor slits <NUM>) are arranged side by side in the direction of air flow.

The windward-side ribs 96a are formed in such a manner that the individual windward-side ribs 96a respectively lying above and below the windward-side fin tab 94a extend in the direction of air flow and between the outdoor flat tubes <NUM> that are adjacent to each other in the up-and-down directions. The leeward-side ribs 96b continuously extend from the leeward-side end portions of the corresponding windward-side ribs 96a further toward the leeward side.

<FIG> is an external perspective view of the indoor unit <NUM>. <FIG> is a schematic plan view of the indoor unit <NUM>, a top panel of which is removed. <FIG> is a schematic sectional side view of the indoor unit <NUM> taken along line A-A in <FIG>.

The indoor unit <NUM> in the present embodiment is an indoor unit of the type that is to be installed in such a way as to be fitted into a cavity of a ceiling of, for example, a room that is a space to be air conditioned. The indoor unit <NUM> is part of the refrigerant circuit <NUM>. The indoor unit <NUM> includes mainly the indoor heat exchanger <NUM>, an indoor fan <NUM>, a casing <NUM>, a flap <NUM>, a bell mouth <NUM>, and a drain pan <NUM>.

The indoor heat exchanger <NUM> is a heat exchanger that functions as an evaporator for refrigerant transmitted from the outdoor heat exchanger <NUM> during the cooling operation and functions as a radiator for refrigerant discharged by the compressor <NUM> during the heating operation. The liquid side of the indoor heat exchanger <NUM> is connected to the indoor-side end portion of the liquid-refrigerant connection pipe <NUM>, and the gas side of the indoor heat exchanger <NUM> is connected to the indoor-side end portion of the gas-refrigerant connection pipe <NUM>.

The indoor fan <NUM> is a centrifugal blower disposed inside a casing body <NUM> of the indoor unit <NUM>. The indoor fan <NUM> creates air flow (denoted by arrows in <FIG>) by sucking room air into the casing <NUM> through a suction opening <NUM> of a decorative panel <NUM>, letting the air through the indoor heat exchanger <NUM>, and then blowing the air out of the casing <NUM> through a blow-out opening <NUM> of the decorative panel <NUM>. The room air supplied by the indoor fan <NUM> in this manner exchanges heat with refrigerant in the indoor heat exchanger <NUM>, and the temperature of the room air is adjusted accordingly.

The casing <NUM> includes mainly the casing body <NUM> and the decorative panel <NUM>.

The casing body <NUM> is installed in such a way as to be inserted into an opening formed in a ceiling U of a room to be air conditioned. The casing body <NUM> is a box-like body and has a substantially octagonal shape defined by alternating long and short sides when viewed in plan. The casing body <NUM> is open on the underside thereof. The casing body <NUM> has a top panel and side panels extending downward from a peripheral edge portion of the top panel.

The decorative panel <NUM> is installed in such a way as to be fitted into the opening of the ceiling U and lies off the top panel and the side panels of the casing body <NUM> when viewed in plan. The decorative panel <NUM> is fitted to a lower part of the casing body <NUM> from the indoor side. The decorative panel <NUM> includes an inner frame 35a and an outer frame 35b. The suction opening <NUM> is provided in on the inner side with respect to the inner frame 35a. The suction opening <NUM> is an opening facing downward and is substantially quadrilateral. A filter <NUM>, which is for removing dust in the air sucked in through the suction opening <NUM>, is disposed above the suction opening <NUM>. The blow-out opening <NUM> and a corner blow-out opening <NUM>, which are openings facing obliquely downward from the lower side, are provided on the inner side with respect to the outer frame 35b and on the outer side with respect to the inner frame 35a. The blow-out opening <NUM> includes a first blow-out opening 37a, a second blow-out opening 37b, a third blow-out opening 37c, and a fourth blow-out opening 37d, whose positions correspond to sides of the substantially quadrilateral shape of the decorative panel <NUM> viewed in plan. The corner blow-out opening <NUM> includes a first corner blow-out opening 38a, a second corner blow-out opening 38b, a third corner blow-out opening 38c, and a fourth corner blow-out opening 38d, whose positions correspond to four corners of the substantially quadrilateral shape of the decorative panel <NUM> viewed in plan.

The flap <NUM> is a member capable of changing the direction of air flow passing through the blow-out opening <NUM>. The flap <NUM> includes a first flap 39a in the first blow-out opening 37a, a second flap 39b in the second blow-out opening 37b, a third flap 39c in the third blow-out opening 37c, and a fourth flap 39d in the fourth blow-out opening 37d. The flaps 39a to 39d are rotatably supported about their respective axes at predetermined positions in the casing <NUM>.

The drain pan <NUM> is disposed below the indoor heat exchanger <NUM> to receive drain water generated in the indoor heat exchanger <NUM> by condensation of moisture in the air. The drain pan <NUM> is fitted in a lower portion of the casing body <NUM>. When viewed in plan, the drain pan <NUM> defines a cylindrical space provided on the inner side with respect to the indoor heat exchanger <NUM> and extending in up-and-down directions. The bell mouth <NUM> is disposed in an inner, lower part of the space. The bell mouth <NUM> guides, to the indoor fan <NUM>, air sucked in through the suction opening <NUM>. When viewed in plan, the drain pan <NUM> defines blow-out flow paths 47a to 47d and corner blow-out flow paths 48a to 48c, which are provided on the outer side with respect to the indoor heat exchanger <NUM> and extend in up-and-down directions. The blow-out flow paths 47a to 47d include: a first blow-out flow path 47a communicating with the first blow-out opening 37a at a lower end thereof; a second blow-out flow path 47b communicating with the second blow-out opening 37b at a lower end thereof; a third blow-out flow path 47c communicating with the third blow-out opening 37c at a lower end thereof; and a fourth blow-out flow path 47d communicating with the fourth blow-out opening 37d at a lower end thereof. The corner blow-out flow paths 48a to 48c include: a first corner blow-out flow path 48a communicating with the first corner blow-out opening 38a at a lower end thereof; a second corner blow-out flow path 48b communicating with the second corner blow-out opening 38b at a lower end thereof; and a third corner blow-out flow path 48c communicating with the third corner blow-out opening 38c at a lower end thereof.

<FIG> is a schematic external perspective view of the indoor heat exchanger <NUM>. <FIG> illustrates the positional relationship between the indoor fins <NUM>, indoor windward flat tubes <NUM>, first indoor leeward flat tubes <NUM>, and second indoor leeward flat tubes <NUM> in a sectional view orthogonal to a direction in which flow paths 81c in the indoor windward flat tubes <NUM>, flow paths 82c in the first indoor leeward flat tubes <NUM>, and flow paths 83c in the second indoor leeward flat tubes <NUM> extend, with the indoor fins <NUM>, the indoor windward flat tubes <NUM>, the first indoor leeward flat tubes <NUM>, and the second indoor leeward flat tubes <NUM> being viewed in the direction in which the flow paths 81c, 82c, and 83c extend. <FIG> is an exploded schematic perspective view of part of a distribution header <NUM> and components adjacent thereto (except for the indoor fins <NUM>). <FIG> is a configuration diagram of the distribution header <NUM> and components adjacent thereto (except for the indoor fins <NUM>), schematically illustrating the layout of the distribution header <NUM> and the components viewed in the direction of air flow. <FIG> is a configuration diagram of the distribution header <NUM> and components adjacent thereto, schematically illustrating the layout of the distribution header <NUM> and the components viewed in the direction in which the flow paths 81c in the indoor windward flat tubes <NUM>, the flow paths 82c in the first indoor leeward flat tubes <NUM>, and the flow paths 83c in the second indoor leeward flat tubes <NUM> extend.

The indoor heat exchanger <NUM> is disposed inside the casing body <NUM> and in the same height position as the indoor fan <NUM> in a manner so as to surround the indoor fan <NUM>. The indoor heat exchanger <NUM> includes mainly a liquid-side header <NUM>, a first gas-side header <NUM>, a second gas-side header <NUM>, indoor flat tubes <NUM>, the indoor fins <NUM>, and the distribution header <NUM>. These components of the indoor heat exchanger <NUM> are all made of aluminum or an aluminum alloy and are bonded to each other, for example, by means of brazing.

The indoor heat exchanger <NUM> includes: an windward heat exchange section 51a (an inner portion in a plan view) on the windward side in the direction of air flow; a second leeward heat exchange section 51c (an outer portion in the plan view) on the leeward side in the direction of air flow; and a first leeward heat exchange section 51b between the windward heat exchange section 51a and the leeward heat exchange section 51c in the direction of air flow.

The liquid-side header <NUM> is an end of the windward heat exchange section 51a of the indoor heat exchanger <NUM> viewed in plan and is a cylindrical member extending in up-and-down directions. The liquid-side header <NUM> is connected with the indoor-side end portion of the liquid-refrigerant connection pipe <NUM>. The liquid-side header <NUM> is also connected with the indoor windward flat tubes <NUM>, which are the indoor flat tubes <NUM> constituting the windward heat exchange section 51a of the indoor heat exchanger <NUM> and are arranged in a manner so as to be adjacent to each other in up-and-down directions.

The first gas-side header <NUM> is an end of the first leeward heat exchange section 51b of the indoor heat exchanger <NUM> viewed in plan and is a cylindrical member extending in up-and-down directions. The first gas-side header <NUM> is connected with a first gas-refrigerant connection pipe 5a, which is a branch pipe extending from the indoor-side end portion of the gas-refrigerant connection pipe <NUM>. The first gas-side header <NUM> is also connected with the first indoor leeward flat tubes <NUM>, which are the indoor flat tubes <NUM> constituting the first leeward heat exchange section 51b of the indoor heat exchanger <NUM> and are arranged in a manner so as to be adjacent to each other in up-and-down directions.

The second gas-side header <NUM> is an end of the second leeward heat exchange section 51c of the indoor heat exchanger <NUM> viewed in plan and is a cylindrical member extending in up-and-down directions. The second gas-side header <NUM> is connected with a second gas-refrigerant connection pipe 5b, which is a branch pipe extending from the indoor-side end portion of the gas-refrigerant connection pipe <NUM>. The second gas-side header <NUM> is also connected with the second indoor leeward flat tubes <NUM>, which are the indoor flat tubes <NUM> constituting the second leeward heat exchange section 51c of the indoor heat exchanger <NUM> and are arranged in a manner so as to be adjacent to each other in up-and-down directions.

The indoor flat tubes <NUM> include: the indoor windward flat tubes <NUM> constituting the windward heat exchange section 51a; the first indoor leeward flat tubes <NUM> constituting the first leeward heat exchange section 51b; and the second indoor leeward flat tubes <NUM> constituting the second leeward heat exchange section 51c. More specifically, the indoor flat tubes <NUM> include: the indoor windward flat tubes <NUM> arranged in a manner so as to be adjacent to each other in up-and-down directions in the windward heat exchange section 51a of the indoor heat exchanger <NUM>; the first indoor leeward flat tubes <NUM> arranged in a manner so as to be adjacent to each other in up-and-down directions in the first leeward heat exchange section 51b of the indoor heat exchanger <NUM>; and the second indoor leeward flat tubes <NUM> arranged in a manner so as to be adjacent to each other in up-and-down directions in the second leeward heat exchange section 51c of the indoor heat exchanger <NUM>. The indoor heat exchanger <NUM> in which three or more heat exchange sections (indoor flat tubes <NUM>) are arranged side by side in the direction of air flow may offer sufficiently higher performance. One end of each of the indoor windward flat tubes <NUM> constituting the windward heat exchange section 51a is connected to the liquid-side header <NUM>, and the other end thereof is connected to a windward-side portion of the distribution header <NUM>. One end of each of the second indoor leeward flat tubes <NUM> constituting the second leeward heat exchange section 51c is connected to the second gas-side header <NUM>, and the other end thereof is connected to a leeward-side portion of the distribution header <NUM>. One end of each of the first indoor leeward flat tubes <NUM> constituting the first leeward heat exchange section 51b is connected to the first gas-side header <NUM>, and the other end thereof is connected to a portion being part of the distribution header <NUM> and located between the portion connected with the indoor windward flat tubes <NUM> and the portion connected with the second indoor leeward flat tubes <NUM>.

The pitch of the indoor windward flat tubes <NUM> in the height direction, the pitch of the first indoor leeward flat tubes <NUM> in the height direction, and the pitch of the second indoor leeward flat tubes <NUM> in the height direction are equal to one another in the indoor heat exchanger <NUM> according to the present embodiment. The flat tubes in the indoor heat exchanger <NUM> according to the present embodiment are arranged as follows. The indoor windward flat tubes <NUM> and the second indoor leeward flat tubes <NUM> overlap each other when viewed in the direction of air flow. The indoor windward flat tubes <NUM> and the second indoor leeward flat tubes <NUM> do not overlap the first indoor leeward flat tubes <NUM> when viewed in the direction of air flow.

The indoor windward flat tubes <NUM>, the first indoor leeward flat tubes <NUM>, and the second indoor leeward flat tubes <NUM> have the same shape and the same dimensions. This enables cost reduction. Each indoor windward flat tube <NUM>, each first indoor leeward flat tube <NUM>, and each second indoor leeward flat tube <NUM> respectively have: upper flat surfaces 81a, 82a, and 83a, each of which faces vertically upward as an upper face; lower flat surfaces 81b, 82b, and 83b, each of which faces vertically downward as a lower face; a large number of small flow paths 81c, 82c, and 83c, through which refrigerant flows. The flow paths 81c of the indoor windward flat tubes <NUM>, the flow paths 82c of the first indoor leeward flat tubes <NUM>, and the flow paths 83c of the second indoor leeward flat tubes <NUM> are arranged in a manner so as to be adjacent to each other in the direction of air flow (denoted by arrows in <FIG> and corresponding to the longitudinal direction of the indoor windward flat tubes <NUM>, the first indoor leeward flat tubes <NUM>, and the second indoor leeward flat tubes <NUM> in the sectional view of the flow paths 81c, 82c, and 83c).

Similarly, the indoor fins <NUM> include indoor fins constituting the windward heat exchange section 51a, indoor fins constituting the first leeward heat exchange section 51b, and indoor fins constituting the second leeward heat exchange section 51c. More Specifically, the indoor fins <NUM> include: indoor fins fixed to the indoor windward flat tubes <NUM> constituting the windward heat exchange section 51a; indoor fins fixed to the first indoor leeward flat tubes <NUM> constituting the first leeward heat exchange section 51b; and indoor fins fixed to the second indoor leeward flat tubes <NUM> constituting the second leeward heat exchange section 51c. The indoor fins <NUM> are arranged side by side in the plate thickness direction of the indoor fins <NUM> along the indoor windward flat tubes <NUM>, the first indoor leeward flat tubes <NUM>, and the second indoor leeward flat tubes <NUM>.

The indoor fins <NUM> constituting the windward heat exchange section 51a, the indoor fins <NUM> constituting the first leeward heat exchange section 51b, and the indoor fins <NUM> constituting the second leeward heat exchange section 51c have the same shape and the same dimensions. This enables cost reduction. The indoor fins <NUM> are plate-shaped members extending in the direction of air flow and in up-and-down directions and are arranged at predetermined spacings in the plate thickness direction thereof. Each indoor fin <NUM> is fixed to the indoor windward flat tubes <NUM>, the first indoor leeward flat tubes <NUM>, or the second indoor leeward flat tubes <NUM>.

Each indoor fin <NUM> includes, for example, a main surface <NUM>, an indoor communicating portion <NUM>, windward portions <NUM>, main slits <NUM>, and communication position slits <NUM>. The main surface <NUM> is part of the indoor fin <NUM> and is a flat portion in which the main slits <NUM> and the communication position slits <NUM> are not provided. The indoor communicating portion <NUM> is part of the indoor fin <NUM> and continuously extends in up-and-down directions on the leeward side of leeward-side end portions of the indoor flat tube <NUM>. The main slits <NUM> are portions cut out and raised in the plate thickness direction from the flat main surface <NUM> and are provided to increase the heat transfer capability of the indoor fin <NUM>. The individual main slits <NUM> are formed in the corresponding windward portions <NUM> of the indoor fin <NUM>. The main slits <NUM> are arranged in rows, each of which includes a plurality of main slits (in the present embodiment, four main slits) arranged side by side in the direction of air flow. Similarly, the communication position slits <NUM> are portions cut and raised in the plate thickness direction from the flat main surface <NUM> in the indoor communicating portion <NUM> and are provided to increase the heat transfer capability of the indoor fin <NUM>. The communication position slits <NUM> are provided on the downstream side of the corresponding main slits <NUM> in the direction of air flow in the respective height positions. Each communication position slit <NUM> is provided in such a manner that the longitudinal direction thereof coincides with the up-and-down directions. The communication position slit <NUM> extends in the up-and-down directions, with the upper end of the communication position slit <NUM> being above the upper ends of the corresponding main slits <NUM> and the lower end of the communication position slit <NUM> being below the lower ends of the corresponding main slits <NUM>. The main slits <NUM> and the communication position slits <NUM> are cut and raised from the flat main surface <NUM> in a manner so as to be on the same side in the plate thickness direction and thus define openings on the upstream side and the downstream side in the direction of air flow.

The distribution header <NUM> is an end portion of the indoor heat exchanger <NUM> viewed in plan. The end portion is opposite to an end portion to which the liquid-side header <NUM>, the first gas-side header <NUM>, and the second gas-side header <NUM> are provided. The distribution header <NUM> is a member extending in up-and-down directions. The distribution header <NUM> is configured to enable flows of refrigerant coming out of the respective indoor flat tubes <NUM> to turn back in such a manner that each flow of refrigerant is distributed to different indoor flat tubes <NUM>.

The distribution header <NUM> includes a tube plate member <NUM> and a distribution member <NUM>.

The tube plate member <NUM> includes a tube plate 71a, an inner side wall 71b, and an outer side wall 71c. The tube plate 71a has openings extending therethrough in the plate thickness direction. The indoor flat tubes <NUM> are fitted in the respective openings. The tube plate 71a has a rectangular face extending in directions orthogonal to the longitudinal direction of the indoor flat tubes <NUM> piercing through the tube plate 71a and is a wall surface of the distribution header <NUM> closer than another wall surface to the indoor flat tubes <NUM>. The inner side wall 71b of the tube plate member <NUM> extends from an inner end portion of the tube plate 71a in the longitudinal direction of the indoor flat tubes <NUM> and is an inner side face of the distribution header <NUM>. The outer side wall 71c of the tube plate member <NUM> extends from an outer end portion of the tube plate 71a in the longitudinal direction of the indoor flat tubes <NUM> and is an outer side face of the distribution header <NUM>.

The distribution member <NUM> includes a turnback wall 72a, an upper end wall 72b, a lower end wall 72c, and partition plates <NUM>. The distribution member <NUM> is fixed to the tube plate member <NUM>, and distribution spaces 70x are defined in the distribution member <NUM> accordingly. The turnback wall 72a has a rectangular face extending parallel to a surface of the tube plate 71a in a manner so as to face the surface of the tube plate 71a and is a wall surface of the distribution header <NUM> opposite to the wall surface closer to the indoor flat tubes <NUM>. The indoor flat tubes <NUM> piercing through the tube plate 71a are not in contact with the turnback wall 72a. The upper end wall 72b extends from an upper end of the turnback wall 72a to an upper edge portion of the tube plate 71a of the tube plate member <NUM> and is an upper face of the distribution header <NUM>. The lower end wall 72c extends from a lower end of the turnback wall 72a to a lower edge portion of the tube plate 71a of the tube plate member <NUM> and is a lower face of the distribution header <NUM>. The partition plates <NUM> respectively extend from different height positions of the turnback wall 72a toward the indoor flat tubes <NUM>. The partition plates <NUM> are disposed between the upper end wall 72b and the lower end wall 72c in a manner so as to be adjacent to each other in up-and-down directions. Specifically, each partition plate <NUM> is a partition between the distribution spaces 70x in the distribution header <NUM> that are adjacent to each other in the up-and-down directions. In other words, the partition plates <NUM> extending from the turnback wall 72a lie horizontally in a manner so as to be in contact with the tube plate 71a, the inner side wall 71b, and the outer side wall 71c. In the present embodiment, upper and lower faces defining the distribution spaces 70x in different height positions are flat surfaces extending in the direction of air flow in the respective height positions.

The distribution spaces 70x adjacent to each other in the height direction are connected with the indoor windward flat tubes <NUM> constituting the windward heat exchange section 51a, the first indoor leeward flat tubes <NUM> constituting the first leeward heat exchange section 51b, and the second indoor leeward flat tubes <NUM> constituting the second leeward heat exchange section 51c in such a manner that the individual distribution spaces are connected with flat tubes in the corresponding height positions. The distribution header <NUM> thus eliminates or reduces the possibility that flows of refrigerant coming out of the indoor windward flat tubes <NUM> in different height positions will mix with each other. Furthermore, the distribution header <NUM> enables flows of refrigerant coming out of the indoor windward flat tubes <NUM> in the respective height positions to turn back in such a manner that each flow of refrigerant is distributed to the corresponding one of the indoor leeward flat tubes <NUM> and the corresponding one of the second indoor leeward flat tubes <NUM>. Specifically, when functioning as an evaporator for refrigerant, the indoor heat exchanger <NUM> causes refrigerant to flow in the following manner: flows of refrigerant coming out of the indoor windward flat tubes <NUM> in the respective height positions turn back in the distribution header <NUM> and are distributed to the first indoor leeward flat tubes <NUM> and the second indoor leeward flat tubes <NUM> in the corresponding height positions. When functioning as a condenser for refrigerant, the indoor heat exchanger <NUM> causes refrigerant to flow in the following manner. Flows of refrigerant coming out of the first indoor leeward flat tubes <NUM> in the respective height positions merge with flows of refrigerant coming out of the second indoor leeward flat tubes <NUM> in the corresponding height positions while these flows of refrigerant turn back in the indoor heat exchanger <NUM>. Then, resultant flows enter the indoor windward flat tubes <NUM> in corresponding height positions.

In the present embodiment, each of the distribution spaces 70x in the respective height positions is connected with the corresponding one of the indoor windward flat tubes <NUM>, the corresponding one of the second indoor leeward flat tubes <NUM>, and the corresponding one of the first indoor leeward flat tubes <NUM>. The indoor windward flat tube <NUM> and the second indoor leeward flat tube <NUM> are in the same height position. The first indoor leeward flat tube <NUM> is in a height position lower than the height position concerned (in a height position lower than the height position of the indoor windward flat tube <NUM> and the second indoor leeward flat tube <NUM> and higher than the height position of another indoor windward flat tube <NUM> and another second indoor leeward flat tube <NUM> immediately below the relevant indoor windward flat tube <NUM> and the relevant second indoor leeward flat tube <NUM>). Consequently, refrigerant flows in the following manner. When, for example, the indoor heat exchanger <NUM> functions as an evaporator for refrigerant, flows of refrigerant coming out of the indoor windward flat tubes <NUM> enter the respective distribution spaces 70x, in which each flow of refrigerant is distributed to the first indoor leeward flat tube <NUM> in a position lower than the position of the indoor windward flat tube <NUM> concerned and the second indoor leeward flat tube <NUM> in the same position as the indoor windward flat tube <NUM> concerned.

The following describes actions of the air conditioner <NUM> with reference to <FIG>. The air conditioner <NUM> performs: the cooling operation during which refrigerant flows through the compressor <NUM>, the outdoor heat exchanger <NUM>, the outdoor expansion valve <NUM>, and the indoor heat exchanger <NUM> in the stated order; and the heating operation during which refrigerant flows through the compressor <NUM>, the indoor heat exchanger <NUM>, the outdoor expansion valve <NUM>, and the outdoor heat exchanger <NUM> in the stated order.

For the cooling operation, the four-way switching valve <NUM> is switched to the connected state (see solid lines in <FIG>) in which the outdoor heat exchanger <NUM> serves as a radiator for refrigerant and the indoor heat exchanger <NUM> serves as an evaporator for refrigerant. The refrigerant circuit <NUM> is configured as follows. Gas refrigerant at a low pressure in the refrigeration cycle is sucked into the compressor <NUM>, compressed to a high pressure in the refrigeration cycle, and is then discharged. The high-pressure gas refrigerant discharged by the compressor <NUM> is transmitted to the outdoor heat exchanger <NUM> through the four-way switching valve <NUM>. After flowing into the outdoor heat exchanger <NUM> functioning as a radiator for refrigerant, the high-pressure gas refrigerant transfers heat in the outdoor heat exchanger <NUM> by exchanging heat with outdoor air supplied as a cooling source by the outdoor fan <NUM> and is thus transformed into high-pressure liquid refrigerant. When the high-pressure liquid refrigerant flows through the outdoor expansion valve <NUM>, the pressure of the high-pressure liquid refrigerant is reduced to a low pressure in the refrigeration cycle. The resultant refrigerant in the gas-liquid two-phase state is transmitted to the indoor unit <NUM> through the liquid-side shutoff valve <NUM> and the liquid-refrigerant connection pipe <NUM>.

In the indoor heat exchanger <NUM>, the low-pressure refrigerant in the gas-liquid two-phase state evaporates by exchanging heat with indoor air supplied as a heat source by the indoor fan <NUM> during the cooling operation. Consequently, the air flowing passing by the indoor heat exchanger <NUM> is cooled, and the room is cooled accordingly. When the air passes by the indoor heat exchanger <NUM>, moisture in the air is condensed, and consequently, condensation forms on the surface of the indoor heat exchanger <NUM>. After evaporating in the indoor heat exchanger <NUM>, the low-pressure gas refrigerant is transmitted to the outdoor unit <NUM> through the gas-refrigerant connection pipe <NUM>.

The low-pressure gas refrigerant in the outdoor unit <NUM> flows through the gas-side shutoff valve <NUM>, the four-way switching valve <NUM>, and the accumulator <NUM> and is then sucked back into the compressor <NUM>. In this way, refrigerant circulates through the refrigerant circuit <NUM> during the cooling operation.

For the heating operation, the four-way switching valve <NUM> is switched to the connected state (see broken lines in <FIG>) in which the outdoor heat exchanger <NUM> serves as an evaporator for refrigerant and the indoor heat exchanger <NUM> serves as a radiator for refrigerant. The refrigerant circuit <NUM> is configured as follows. Gas refrigerant at a low pressure in the refrigeration cycle is sucked into the compressor <NUM>, compressed to a high pressure in the refrigeration cycle, and is then discharged. The high-pressure gas refrigerant discharged by the compressor <NUM> is transmitted to the indoor unit <NUM> through the four-way switching valve <NUM>, the gas-side shutoff valve <NUM>, and the gas-refrigerant connection pipe <NUM>.

In the indoor heat exchanger <NUM>, the high-pressure gas refrigerant transfers heat by exchanging heat with indoor air supplied as a cooling source by the indoor fan <NUM> and is thus transformed into high-pressure liquid refrigerant. Consequently, the air flowing passing by the indoor heat exchanger <NUM> is heated, and the room is heated accordingly. After transferring heat in the indoor heat exchanger <NUM>, the high-pressure liquid refrigerant is transmitted to the outdoor unit <NUM> through the liquid-refrigerant connection pipe <NUM>.

The high-pressure liquid refrigerant in the outdoor unit <NUM> flows through the liquid-side shutoff valve <NUM> and enters the outdoor expansion valve <NUM>, where the pressure of the refrigerant is reduced to a low pressure in the refrigeration cycle. The resultant refrigerant is low-pressure refrigerant in the gas-liquid two-phase state. After being decompressed in the outdoor expansion valve <NUM> and flowing into the outdoor heat exchanger <NUM> functioning as an evaporator for refrigerant, the low-pressure refrigerant in the gas-liquid two-phase state evaporates by exchanging heat with outdoor air supplied as a heat source by the outdoor fan <NUM> and is thus transformed into low-pressure gas refrigerant. The low-pressure gas refrigerant flows through the four-way switching valve <NUM> and the accumulator <NUM> and is then sucked back into the compressor <NUM>. In this way, refrigerant circulates through the refrigerant circuit <NUM> during the heating operation.

An indoor heat exchanger proposed and known in the art includes, for added performance, heat transfer tubes arranged in columns adjacent to each other in the direction of air flow. Such an indoor heat exchanger may include: cylindrical heat transfer tubes arranged in columns adjacent to each other in the direction of air flow; and connection pipes each of which is circular in cross section and forms a connections between an end portion of a cylindrical heat transfer tube in a column and an end portion of a cylindrical heat transfer tube in another column. Each connection pipe branches off from a branch portion, where a flow of refrigerant is divided and distributed accordingly.

However, no mention is made of a structure for distributing refrigerant in a heat exchanger that includes flat tubes having a flat shape instead of including the cylindrical heat transfer tubes.

As a workaround, the indoor heat exchanger <NUM> according to the present embodiment enables refrigerant to flow in the following manner. When, for example, the indoor heat exchanger <NUM> functions as an evaporator for refrigerant, flows of refrigerant coming out of the indoor windward flat tubes <NUM> having a flat shape are distributed in the respective distribution spaces 70x and enter the corresponding first indoor leeward flat tubes <NUM> and the corresponding second indoor leeward flat tubes <NUM> as denoted by arrows in <FIG>. Thus, the indoor flat tubes <NUM> having a flat shape may be used in the indoor heat exchanger <NUM> in a manner so as to distribute flows of refrigerant appropriately.

The distribution spaces 70x are provided to an end portion of the indoor heat exchanger <NUM>. Owing to this feature of the indoor heat exchanger <NUM> according to the present embodiment, flows of refrigerant coming out of the indoor windward flat tubes <NUM> can not only branch off to enter the corresponding first indoor leeward flat tubes <NUM> and the corresponding second indoor leeward flat tubes <NUM> but also turn back.

The indoor heat exchanger <NUM> according to the present embodiment enables appropriate distribution of refrigerant just by connecting the indoor windward flat tubes <NUM>, the first indoor leeward flat tubes <NUM>, and the second indoor leeward flat tubes <NUM> to the distribution header <NUM>. In particular, the distribution header <NUM> in the present embodiment includes members (the tube plate member <NUM> and the distribution member <NUM>) intended to be shared among the indoor windward flat tubes <NUM> lined up in the height direction, the first indoor leeward flat tubes <NUM> lined up in the height direction, and the second indoor leeward flat tubes <NUM> lined up in the height direction. This eliminates a complicated procedure for forming connections between end portions of the indoor flat tubes <NUM> in the respective heights by using independent connection pipes such as U-tubes or Y-tubes.

The flat tubes in the indoor heat exchanger <NUM> according to the present embodiment are arranged as follows. The indoor windward flat tubes <NUM> and the first indoor leeward flat tubes <NUM> do not overlap each other when viewed in the direction of air flow. Similarly, the first indoor leeward flat tubes <NUM> and the second indoor leeward flat tubes <NUM> do not overlap each other when viewed in the direction of air flow. This layout enables the air flow created by the indoor fan <NUM> to come into sufficient contact with the indoor windward flat tubes <NUM>, the first indoor leeward flat tubes <NUM>, and the second indoor leeward flat tubes <NUM>. The efficiency of heat exchange may be enhanced accordingly.

In the indoor heat exchanger <NUM> according to the present embodiment, the first indoor leeward flat tube <NUM> and the second indoor leeward flat tube <NUM> in the respective columns adjacent to each other in the direction of air flow are connected to the same distribution space 70x. A flow of refrigerant coming out of the indoor windward flat tube <NUM> may thus be distributed to the first indoor leeward flat tube <NUM> and the second indoor leeward flat tube <NUM> in different columns.

When the indoor heat exchanger <NUM> functions as an evaporator for refrigerant, the temperature of air passing by the indoor heat exchanger <NUM> tends to be lower on the downstream side than on the upstream side in the direction of air flow. Consequently, the first indoor leeward flat tubes <NUM> on the upstream side in the direction of air flow are more likely to be in contact with high-temperature air than the second indoor leeward flat tubes <NUM> on the downstream side are.

With consideration given to the tendency, the indoor heat exchanger <NUM> according to the present embodiment is configured as follows. Flows of refrigerant turn back while flowing through the indoor heat exchanger <NUM> functioning as an evaporator. With the first indoor leeward flat tube <NUM> and the second indoor leeward flat tube <NUM> being connected to the same distribution space 70x, the height position at which the first indoor leeward flat tube <NUM> is connected to the distribution header <NUM> is lower than the height position at which the second indoor leeward flat tube <NUM> is connected to the distribution header <NUM>. When the indoor heat exchanger <NUM> functions as an evaporator, gas-liquid two-phase refrigerant coming out of the indoor windward flat tube <NUM> includes refrigerants of different specific gravities, and the refrigerant of a high specific gravity, such as a liquid refrigerant, tends to be led to the first indoor leeward flat tube <NUM> instead of being led to the second indoor leeward flat tubes <NUM>.

Thus, the gas-liquid two-phase refrigerant coming out of the indoor windward flat tube <NUM> flows in such a manner that the refrigerant of a high specific gravity is preferentially conducted to the first indoor leeward flat tube <NUM>, by which higher-temperature air passes. The efficiency of heat exchange in the indoor heat exchanger <NUM> as a whole may be enhanced accordingly.

Refrigerant evaporates and gasifies when flowing through the indoor windward flat tubes <NUM> of the indoor heat exchanger <NUM> according to the present embodiment. The first indoor leeward flat tubes <NUM> and the second indoor leeward flat tubes <NUM> are provided to a portion where flows of the refrigerant turn back. The area of flow paths defined by these indoor leeward flat tubes is greater than the area of the flow paths defined by the indoor windward flat tubes <NUM>, and the pressure loss through the indoor heat exchanger <NUM> may thus be low.

The indoor heat exchanger including the indoor flat tubes <NUM> arranged in three columns adjacent to each other in the direction of air flow has been described so far as an example of the indoor heat exchanger <NUM> according to the embodiment above.

Alternatively, an indoor heat exchanger <NUM> may be provided. As illustrated in <FIG>, the indoor flat tubes <NUM> are arranged in more than three columns, or more specifically, four columns adjacent to each other in the direction of air flow. In other words, the indoor heat exchanger <NUM> according to the embodiment above may include a windward heat exchange section 151d, which includes indoor windward flat tubes <NUM> on the upstream side of the indoor windward flat tubes <NUM> in the direction of air flow.

The indoor heat exchanger <NUM> including the indoor flat tubes <NUM> arranged in four columns is preferably configured to cause refrigerant to flow in the following manner. When, for example, the indoor heat exchanger <NUM> is used as an evaporator, flows of refrigerant coming out of the indoor windward flat tubes <NUM> and <NUM> in two respective columns on the upstream side of air flow are distributed to the first indoor leeward flat tube <NUM> and the second indoor leeward flat tube <NUM> in two respective columns on the downstream side in the direction of air flow while turning back in the distribution space 70x.

Furthermore, the indoor heat exchanger <NUM> including the indoor flat tubes <NUM> arranged in four columns is preferably configured as follows. With the indoor flat tubes <NUM> being arranged in columns to allow flows of refrigerant to turn back and flow therethrough, each of the indoor flat tubes <NUM> on the downstream side in the direction of air flow (the first indoor leeward flat tubes <NUM> in <FIG>) is in a position lower than the position in the height direction of the corresponding one of the indoor flat tubes <NUM> (the second indoor leeward flat tube <NUM> in <FIG>) further on the downstream side in the direction of air flow. As in the case above, this configuration offers the following advantage: with refrigerants of different specific gravities being included in the gas-liquid two-phase refrigerant, refrigerant of a high specific gravity may be efficiently led to the indoor flat tubes <NUM> that are located on the windward side to allow refrigerant to turn back and flow therethrough.

The indoor heat exchanger in which the partition plates <NUM> of the distribution header <NUM> lie horizontally to define the distribution spaces 70x located in different height positions and extending in the direction of air flow in the respective height positions has been described above as an example of the indoor heat exchanger <NUM> according to the embodiment above.

Alternatively, as illustrated in <FIG>, an indoor heat exchanger <NUM> configured to have partition plates <NUM> and distribution spaces 270x may be provided. The partition plates <NUM> of the distribution header <NUM> are recessed downward in positions corresponding to the positions of the first indoor leeward flat tubes <NUM> in the direction of air flow. The distribution spaces 270x are defined in such a manner that each distribution space 270x includes a portion corresponding to the first indoor leeward flat tube <NUM> and located in a position lower than the position of a portion on the upstream side in the direction of air flow and lower than the position of a portion on the downstream side in the direction of air flow.

The distribution spaces 270x shaped as described above in the distribution header <NUM> of the indoor heat exchanger <NUM> eliminate or reduce the possibility that flows of refrigerant coming out of the indoor windward flat tubes <NUM> will be conducted to the second indoor leeward flat tubes <NUM>. Consequently, flows of refrigerant may be distributed in a manner so as to be conducted to the first indoor leeward flat tubes <NUM> more efficiently. Thus, flows of refrigerant having turned back are more likely to be conducted to flat tubes located on the windward side of the other flat tubes. The efficiency of heat exchange may be further enhanced accordingly.

Alternatively, as illustrated in <FIG>, an indoor heat exchanger <NUM> configured to have partition plates <NUM> may be provided. The partition plates <NUM> are provided in the respective height positions. Each partition plate <NUM> is configured to have a first flow path <NUM>, through which part of refrigerant coming out of the indoor windward flat tube <NUM> is led to the first indoor leeward flat tube <NUM>; and a second flow path <NUM>, through which the rest of the refrigerant coming out of the indoor windward flat tube <NUM> is led to the second indoor leeward flat tube <NUM> in each distribution spaces 370x of the respective height positions. In the example concerned, flat tubes are disposed in such a manner that in each height position, the corresponding one of the indoor windward flat tubes <NUM>, the corresponding one of first indoor leeward flat tubes <NUM>, and the corresponding one of the second indoor leeward flat tubes <NUM> overlap each other in the direction of air flow.

Each partition plate <NUM> includes a first guide 373a and a second guide 373b. The first guide 373a extends downward from a region being part of the lower face of the partition plate <NUM> and located between the indoor windward flat tube <NUM> and the first indoor leeward flat tube <NUM>. The first guide 373a extends to about the height position of the indoor windward flat tube <NUM> and the first indoor leeward flat tube <NUM>. The second guide 373b extends downward from a region being part of the lower face of the partition plate <NUM> and located between the first indoor leeward flat tube <NUM> and the second indoor leeward flat tube <NUM>. The second guide 373b extends to a position lower than the position of the first indoor leeward flat tube <NUM>, lies below and along the first indoor leeward flat tube <NUM>, and ends short of the indoor windward flat tube <NUM>. The first guide 373a and the second guide 373b extend from the tube plate 71a to the turnback wall 72a of the distribution header <NUM>.

The first flow path <NUM> is defined between a lower end of the first guide 373a and an end portion of the second guide 373b on the upstream side in the direction of air flow. The first flow path <NUM> has a first inlet 82x, which is provided in the upstream-side end portion of the first flow path <NUM>. The second flow path <NUM> is defined between a portion being part of the second guide 373b and lying below and along the first indoor leeward flat tube <NUM> and the upper face of another partition plate <NUM> located below the partition plate <NUM> concerned. The second flow path <NUM> has a second inlet 83x, which is provided in an upstream-side end portion of the second flow path <NUM>.

Furthermore, the first inlet 82x, through which a flow of refrigerant coming out of the indoor windward flat tube <NUM> and directed to the first indoor leeward flat tube <NUM> passes, is wider than the second inlet 83x, through which a flow of refrigerant coming out of the indoor windward flat tube <NUM> and directed to the second indoor leeward flat tube <NUM> passes. Owing to this configuration, a flow of refrigerant coming out of the indoor windward flat tube <NUM> tends to pass through a wider inlet, namely, the first inlet 82x instead of passing through a narrower inlet, namely, the second inlet 83x. Flows of refrigerant are thus conducted to the first indoor leeward flat tubes <NUM> more efficiently, and the efficiency of heat exchange may be enhanced accordingly.

The indoor heat exchanger in which the indoor flat tubes <NUM> in different columns are in the same height position has been described so far as an example of the indoor heat exchanger <NUM> according to the modification C. However, it is not required that these indoor flat tubes <NUM> be in the same height position. The indoor heat exchanger may include a portion in which the indoor flat tube <NUM> do not overlap each other when viewed in the direction of air flow.

Alternatively, as illustrated in <FIG>, an indoor heat exchanger <NUM> configured to have partition plates <NUM> may be provided. The partition plates <NUM> are provided in the respective height positions. Each partition plate <NUM> is configured to have a third flow path <NUM>, through which part of refrigerant coming out of the indoor windward flat tube <NUM> is led to the first indoor leeward flat tube <NUM>; and a fourth flow path <NUM>, through which the rest of the refrigerant coming out of the indoor windward flat tube <NUM> is led to the second indoor leeward flat tube <NUM> in each distribution spaces 470x of the respective height positions. In the example concerned, flat tubes are disposed in such a manner that in each height position, the corresponding one of the indoor windward flat tubes <NUM>, the corresponding one of the first indoor leeward flat tubes <NUM>, and the corresponding one of the second indoor leeward flat tubes <NUM> overlap each other in the direction of air flow.

Each partition plate <NUM> includes a third guide 473a and a fourth guide 473b. The third guide 473a extends upward from a region being part of the upper face of the partition plate <NUM> and located between the indoor windward flat tube <NUM> and the first indoor leeward flat tube <NUM>. The third guide 473a extends to about the height position of the indoor windward flat tube <NUM> and the first indoor leeward flat tube <NUM>. The fourth guide 473b extends upward from a region being part of the upper face of the partition plate <NUM> and located between the first indoor leeward flat tube <NUM> and the second indoor leeward flat tube <NUM>. The fourth guide 473b extends to a position higher than the position of the first indoor leeward flat tube <NUM>, lies above and along the first indoor leeward flat tube <NUM>, and ends short of the indoor windward flat tube <NUM>. The third guide 473a and the fourth guide 473b extend from the tube plate 71a to the turnback wall 72a of the distribution header <NUM>.

The third flow path <NUM> is defined between an upper end of the third guide 473a and an end portion of the fourth guide 473b on the upstream side in the direction of air flow. The third flow path <NUM> has a third inlet 82y, which is provided in the upstream-side end portion of the third flow path <NUM>. The fourth flow path <NUM> is defined between a portion being part of the fourth guide 473b and lying above and along the first indoor leeward flat tube <NUM> and the lower face of another partition plate <NUM> located above the partition plate <NUM> concerned. The fourth flow path <NUM> has a fourth inlet 83y, which is provided in an upstream-side end portion of the fourth flow path <NUM>.

Furthermore, the third inlet 82y, through which a flow refrigerant coming out of the indoor windward flat tube <NUM> and directed to the first indoor leeward flat tube <NUM> passes, is in the height position lower than the height position of the fourth inlet 83y, through which a flow of refrigerant coming out of the indoor windward flat tube <NUM> and directed to the second indoor leeward flat tube <NUM> passes. Gas-liquid two-phase refrigerant coming out of the indoor windward flat tube <NUM> includes refrigerants of different specific gravities. Owing to the configuration above, the refrigerant of a high specific gravity, such as a liquid refrigerant, tends to pass through a lower inlet, namely, the third inlet 82y instead of passing through a higher inlet, namely, the fourth inlet 83y. Flows of refrigerant are thus conducted to the first indoor leeward flat tubes <NUM> more efficiently, and the efficiency of heat exchange may be enhanced accordingly.

The indoor heat exchanger in which the indoor flat tubes <NUM> in different columns are in the same height position has been described so far as an example of the indoor heat exchanger <NUM> according to the modification D. However, it is not required that these indoor flat tubes <NUM> be in the same height position. The indoor heat exchanger may include a portion in which the indoor flat tube <NUM> do not overlap each other when viewed in the direction of air flow.

The feature of the modification C may be combined with the feature of the modification D. With refrigerants of different specific gravities being included in gas-liquid two-phase refrigerant coming out of the indoor windward flat tube <NUM>, the refrigerant of a higher specific gravity, such as a liquid refrigerant, may be led to the first indoor leeward flat tube <NUM> more efficiently, owing to the third inlet 82y being in a position lower than the position of the fourth inlet 83y and being wider than the fourth inlet 83y. In this case, the third inlet 82y and the fourth inlet 83y may be shaped in such a manner that the third inlet 82y in up-and-down directions is wider than the fourth inlet 83y in the up-and-down directions when viewed in section as in <FIG>. Alternatively, the gap between the tube plate 71a and the turnback wall 72a may be partially narrowed or an intervening member may be disposed between the tube plate 71a and the turnback wall 72a. The third inlet 82y in up-and-down direction may thus be wider than the fourth inlet 83y in the up-and-down directions when viewed in a direction orthogonal to the sheet of <FIG>, which is a sectional view.

The indoor heat exchanger <NUM> according to the embodiment above has been described so far, with no consideration given to the wind speed distribution provided by the air flow from the indoor fan <NUM>, especially in use environments.

Alternatively, an indoor heat exchanger <NUM>, which is configured as illustrated in <FIG>, may be provided.

The indoor heat exchanger <NUM> includes: windward flat tubes 581a and 581b, which constitute the windward heat exchange section 51a on the upstream side in the direction of air flow; second leeward flat tubes 583a and 583b, which constitute the second leeward heat exchange section 51c on the downstream side in the direction of air flow; and first leeward flat tubes 582a and 582b, which constitute the first leeward heat exchange section 51b located between the windward flat tube 581a and the second leeward flat tube 583a and between the windward flat tube 581b and the second leeward flat tube 583b in the direction of air flow. The windward flat tubes 581a and 581b include an upper windward flat tube 581a and a lower windward flat tube 581b arranged in this order from top to bottom in the height direction. The first leeward flat tubes 582a and 582b include an upper first leeward flat tube 582a and a lower first leeward flat tube 582b arranged in this order from top to bottom in the height direction. The second leeward flat tube 583a and 583b include an upper second leeward flat tube 583a and a lower second leeward flat tube 583b arranged in this order from top to bottom in the height direction.

Furthermore, the distribution header <NUM> includes a partition plate <NUM>, which includes a main partition portion 573a and a sub-partition portion 573b. The main partition portion 573a lies horizontally in a manner so as to vertically partition off the indoor flat tubes <NUM> (in the example concerned, two indoor flat tubes <NUM>) adjacent to each other in the up-and-down directions, or more specifically, the upper windward flat tube 581a and the lower windward flat tube 581b, the upper first leeward flat tube 582a and the lower first leeward flat tube 582b, and the upper second leeward flat tube 583a and the lower second leeward flat tube 583b. The sub-partition portion 573b extends downward from a region being part of the lower surface of the main partition portion 573a and located between the upper first leeward flat tube 582a and the upper second leeward flat tube 583a. The sub-partition portion 573b extends to a position lower than the position of the lower first leeward flat tube 582b and extends windward in manner so as to lie below and along the lower first leeward flat tube 582b. The sub-partition portion 573b further extends upward between the lower windward flat tube 581b and the lower first leeward flat tube 582b and extends windward to the inner side wall 71b in a manner so as to lie above the lower windward flat tube 581b. The main partition portion 573a and the sub-partition portion 573b extend from the tube plate 71a side to the turnback wall 72a.

The main partition portion 573a and the sub-partition portion 573b mentioned above partition the distribution header <NUM> into a first distribution space 82z and a second distribution space 83z. The upper windward flat tube 581a, the upper first leeward flat tube 582a, and the lower first leeward flat tube 582b are placed in the first distribution space 82z, and the lower windward flat tube 581b, the upper second leeward flat tube 583a, and the lower second leeward flat tube 583b are placed in the second distribution space 83z. The number of the indoor flat tubes <NUM> (two in the example concerned, where the upper first leeward flat tube 582a and the lower first leeward flat tube 582b are provided) in the first leeward heat exchange section 51b connected to the first distribution space 82z, to which the upper windward flat tube 581a is connected, is greater than the number of the indoor flat tubes <NUM> (zero in the example concerned) in the first leeward heat exchange section 51b connected to the second distribution space 83z, to which the lower windward flat tube 581b is connected.

The indoor heat exchanger <NUM> according to the modification E is to be used in the environment where air flow is supplied in such a manner that the wind speed is lower in the upper portion and higher in the lower portion as denoted by arrows of different sizes in <FIG>. The air flow with the wind speed distribution is not limited. The wind speed distribution may be due the presence or absence of something that offers air passage resistance in the middle of air flow or may be due to varying distances from the indoor fan <NUM>.

In the indoor heat exchanger <NUM> configured as described above, the speed of the air flow around the upper windward flat tube 581a is lower than the speed of the air flow around the lower windward flat tube 581b. The efficiency of heat exchange may thus be lower in the upper windward flat tube 581a than in the lower windward flat tube 581b. When, for example, the indoor heat exchanger <NUM> is used as an evaporator for refrigerant, the degree of evaporation of a flow of refrigerant through the upper windward flat tube 581a may not be as sufficient as the degree of evaporation of a flow of refrigerant through the lower windward flat tube 581b, and a large proportion of refrigerant coming out of the upper windward flat tube 581a will presumably be liquid refrigerant.

As a workaround, the indoor heat exchanger <NUM> has the following feature. When, for example, the indoor heat exchanger <NUM> is used as an evaporator for refrigerant, a flow of refrigerant coming out of the upper windward flat tube 581a is distributed to the upper first leeward flat tube 582a and the lower first leeward flat tube 582b while passing through the first distribution space 82z, and a flow of refrigerant coming out of the lower windward flat tube 581b is distributed to the upper second leeward flat tube 583a and the lower second leeward flat tube 583b while passing through the second distribution space 83z. As for the air flow passing by the indoor heat exchanger <NUM> functioning as an evaporator, the temperature of air passing by the upper first leeward flat tube 582a and the lower first leeward flat tube 582b tends to be higher than the temperature of air passing by the upper second leeward flat tube 583a and the lower second leeward flat tube 583b. The degree of evaporation of a flow of refrigerant through the upper windward flat tube 581a, which is in a position where the wind speed is relatively small, may be insufficient, and as a result, a large proportion of refrigerant coming out of the upper windward flat tube 581a will presumably be liquid refrigerant; nevertheless, the relevant refrigerant will be able to evaporate sufficiently while being conducted through the upper first leeward flat tube 582a and the lower first leeward flat tube 582b supplied with higher-temperature air. Meanwhile, the degree of evaporation of a flow of refrigerant through the lower windward flat tube 581b, which is in a position where the wind speed is relatively high, may be sufficient, and as a result, a small proportion of refrigerant coming out of the lower windward flat tube 581b will presumably be liquid refrigerant. Thus, there is no disadvantage of conducting the relevant refrigerant through the upper second leeward flat tube 583a and the lower second leeward flat tube 583b supplied with relatively low-temperature air.

Consequently, flows of refrigerant respectively coming out of the upper first leeward flat tube 582a and the lower first leeward flat tube 582b through the first distribution space 82z and flows of refrigerant respectively coming out of the upper second leeward flat tube 583a and the lower second leeward flat tube 583b through the second distribution space 83z may thus fall into similar states, irrespective of any difference between the speed of air passing by the upper windward flat tube 581a and the speed of air passing by the lower windward flat tube 581b.

Although the first distribution space 82z and the second distribution space 83z described above are included in the distribution header <NUM>, it is not required that this configuration be adopted in all of the height positions in the indoor heat exchanger. For example, the configuration concerned may be adopted in only part of the indoor heat exchanger, or more specifically, an upper or lower end where the wind speed distribution is found.

The embodiment above indicates that the indoor heat exchanger <NUM> includes the indoor flat tubes <NUM> arranged in columns adjacent to each other in the direction of air flow and that the outdoor heat exchanger <NUM> includes the outdoor flat tubes <NUM> arranged in a column, which stands alone in the direction of air flow.

Claim 1:
A heat exchanger (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) in which heat is exchanged between refrigerant flowing inside and air flowing outside, the heat exchanger comprising:
at least one upstream-side flat tube (<NUM>, <NUM>, 581a, 581b);
at least two downstream-side flat tubes (<NUM>, <NUM>, 582a, 582b, 583a, 583b) on a downstream side of the upstream-side flat tube in a direction of air flow; and
a space formation member (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, 573a, 573b) that defines distribution space (70x, 270x, 370x, 470x, 82z, 83z) in which the refrigerant coming out of the upstream-side flat tube is distributed to the at least two downstream-side flat tubes, characterized in that
the downstream-side flat tubes include at least one first downstream-side flat tube (<NUM>)
and at least one second downstream-side flat tube (<NUM>)
on a downstream side of the first downstream-side flat tube (<NUM>) in the direction of air flow, wherein
a first communicating channel (<NUM>) and a second communicating channel (<NUM>) are provided in the distribution space to lead the refrigerant coming out of the upstream-side flat tube to the first downstream-side flat tube (<NUM>) and the second downstream-side flat tube (<NUM>), respectively, and
a flow path defined by the first communicating channel (<NUM>) is wider than a flow path defined by the second communicating channel (<NUM>).