Patent Description:
In general, heat exchangers employ a refrigerant distribution technique in which two-phase gas-liquid refrigerant is caused to flow from a distributor (header), configured to distribute the refrigerant, into a plurality of heat-transfer tubes connected to the distributor. In one disclosed example of such a heat exchanger, if the refrigerant is caused to flow horizontally in the distributor, the flow resistance is increased by a wall provided inside the distributor, aiming at even distribution of the two-phase gas-liquid refrigerant flowing into the plurality of heat-transfer tubes connected to the distributor (see Patent Literature <NUM>). The performance of the heat exchanger depends on the amounts of liquid refrigerant flowing into the respective heat-transfer tubes (the distribution characteristic).

However, if the distributor such as the one disclosed by Patent Literature <NUM> is vertically oriented and the two-phase gas-liquid refrigerant flows thereinto from a lower part thereof, the liquid refrigerant in the two-phase gas-liquid refrigerant flowing in the distributor is difficult to reach a downstream part (upper part) because of gravity. In particular, under a low load, the flow rate of the liquid refrigerant supplied into the heat-transfer tubes is relatively high for those heat-transfer tubes that are located in a lower part but is relatively low for those heat-transfer tubes that are located in an upper part.

Therefore, if the distributor is configured such that two-phase gas-liquid refrigerant is received at a lower position and flows upward inside the distributor, the distribution of the refrigerant may become uneven among the heat-transfer tubes arranged side by side in the top-bottom direction of the distributor. Consequently, the performance of the heat exchanger may be deteriorated. The performance of such a heat exchanger can be improved by causing an increased amount of liquid refrigerant to flow into not only those heat transfer tubes that are located in a lower part but also those heat transfer tubes that are located in an upper part.

The present invention has been made to solve the above problem and to provide a heat exchanger and an air-conditioning apparatus that are excellent in the performance of evenly distributing two-phase gas-liquid refrigerant.

A heat exchanger according to the present invention includes a distributor extending in a top-bottom direction in a form of a pipe and in which refrigerant flows; a plurality of heat-transfer tubes connected to the distributor while being arranged at intervals from one another in the top-bottom direction, the heat-transfer tubes receiving the refrigerant flowing from the distributor; and a refrigerant inflow pipe connected to the distributor at a position below a lowest one of the plurality of heat-transfer tubes and through which the refrigerant flows into the distributor. The plurality of heat-transfer tubes connected to the distributor stick out into an internal space of the distributor such that when the plurality of heat-transfer tubes and a part defined as the internal space are projected on a plane perpendicular to an axial direction of the distributor, the plurality of heat-transfer tubes occupies one-half or greater of the part defined as the internal space. The distributor includes an orifice plate being in a form of a plate and dividing the internal space into an upper space and a lower space in a longitudinal direction of the distributor. The orifice plate is located above the lowest one of the plurality of heat-transfer tubes in the internal space. The orifice plate has an orifice that is a through-hole through which the upper space and the lower space communicate with each other.

An air-conditioning apparatus according to the present invention includes the heat exchanger according to the one embodiment of the present invention, and a fan configured to supply air to the plurality of heat-transfer tubes.

The heat exchanger according to the invention includes the distributor including the orifice plate having the orifice, and the orifice plate is located above the lowest one of the plurality of heat-transfer tubes. The refrigerant gathers the flow speed thereof by passing through the orifice, so that liquid refrigerant reaches an upper part of the distributor. Therefore, in the distributor including the orifice plate, the amount of liquid refrigerant to be supplied into those heat-transfer tubes that are connected to an upper part of the distributor is greater than in a distributor including no orifice plate. Such a configuration of the distributor prevents the separation between the gas refrigerant and the liquid refrigerant contained in the two-phase gas-liquid refrigerant that may occur while the refrigerant flows upward in the distributor. Accordingly, the gas refrigerant and the liquid refrigerant are evenly distributed to those heat-transfer tubes that are located in a downstream part of the distributor.

The air-conditioning apparatus according to the present invention includes the heat exchanger configured as above. Therefore, the separation between the gas refrigerant and the liquid refrigerant in the two-phase gas-liquid refrigerant is prevented. Accordingly, the gas refrigerant and the liquid refrigerant are evenly distributed to those heat-transfer tubes that are located in a downstream part of the distributor.

In the drawings including <FIG> to be referred to below, the same reference signs denote the same or equivalent elements, which applies throughout the description of the following embodiments. Furthermore, in each of the embodiments, elements that are the same as or equivalent to those described in any of the preceding embodiments are denoted by the same reference signs, and description thereof may be omitted.

<FIG> illustrates a refrigerant circuit configuration of an air-conditioning apparatus <NUM> according to Embodiment <NUM> in a heating operation. <FIG> illustrates a refrigerant circuit configuration of the air-conditioning apparatus <NUM> according to Embodiment <NUM> in a cooling operation. The arrows provided in <FIG> represent the direction of refrigerant flow generated in the air-conditioning apparatus <NUM> during the heating operation. The arrows provided in <FIG> represent the direction of refrigerant flow generated in the air-conditioning apparatus <NUM> during the cooling operation.

Referring to <FIG>, the configuration and operations of the air-conditioning apparatus <NUM> will now be described. The air-conditioning apparatus <NUM> includes an outdoor heat exchanger <NUM> and an indoor heat exchanger <NUM>, as with a room air conditioner for home use or a packaged air conditioner for store or office use. The air-conditioning apparatus <NUM> described herein includes one outdoor heat exchanger <NUM> and one indoor heat exchanger <NUM>. Alternatively, the air-conditioning apparatus <NUM> may include a plurality of outdoor heat exchangers <NUM> and a plurality of indoor heat exchangers <NUM>. The numbers of outdoor heat exchangers <NUM> and indoor heat exchangers <NUM> are not limited to those recognizable in <FIG> and may be determined considering where the air-conditioning apparatus <NUM> is to be installed.

The air-conditioning apparatus <NUM> includes an outdoor heat exchanger <NUM>, an indoor heat exchanger <NUM>, a compressor <NUM>, an expansion device <NUM>, and a flow switching device <NUM>. Such devices are connected to one another by a refrigerant pipe <NUM>, whereby a refrigerant circuit in which refrigerant flows is established. The air-conditioning apparatus <NUM> further includes an outdoor fan <NUM>, which supplies air to the outdoor heat exchanger <NUM>; and an indoor fan <NUM>, which supplies air to the indoor heat exchanger <NUM>.

The outdoor heat exchanger <NUM> causes the refrigerant flowing thereinside and the air supplied thereto by the outdoor fan <NUM> to exchange heat with each other. The outdoor heat exchanger <NUM> serves as an evaporator in the heating operation and as a condenser in the cooling operation. The indoor heat exchanger <NUM> causes the refrigerant flowing thereinside and indoor air supplied thereto by the indoor fan <NUM> to exchange heat with each other. The indoor heat exchanger <NUM> serves as a condenser in the heating operation and as an evaporator in the cooling operation.

The compressor <NUM> is a fluid machine that compresses the refrigerant sucked thereinto and discharges the compressed refrigerant. The expansion device <NUM> is, for example, an expansion valve and decompresses the refrigerant. The expansion device <NUM> may be an electronic expansion valve whose opening degree is adjusted under the control of a controller (not illustrated). The flow switching device <NUM> is, for example, a four-way valve and is controlled by the controller (not illustrated) to switch the refrigerant passageway between the one for the cooling operation of the air-conditioning apparatus <NUM> and the one for the heating operation of the air-conditioning apparatus <NUM>.

Referring to <FIG>, how the air-conditioning apparatus <NUM> works in the heating operation will now be described by following the flow of the refrigerant. First, low-temperature, low-pressure gas refrigerant is sucked into the compressor <NUM>, where the sucked refrigerant is compressed into high-temperature, high-pressure gas refrigerant. The high-temperature, high-pressure gas refrigerant resulting from the compression by the compressor <NUM> is discharged from the compressor <NUM>, flows through the flow switching device <NUM>, and then flows into the indoor heat exchanger <NUM>. The high-temperature, high-pressure gas refrigerant having flowed into the indoor heat exchanger <NUM> transfers heat to the air, supplied from the indoor fan <NUM>, by exchanging heat with the air and is thus condensed into high-temperature, high-pressure liquid refrigerant, which is discharged from the indoor heat exchanger <NUM>.

The liquid refrigerant discharged from the indoor heat exchanger <NUM> is expanded and decompressed by the expansion device <NUM> into low-temperature, low-pressure two-phase gas-liquid refrigerant, which flows into the outdoor heat exchanger <NUM>. The two-phase gas-liquid refrigerant having flowed into the outdoor heat exchanger <NUM> receives heat from outdoor air, supplied from the outdoor fan <NUM>, by exchanging heat with the outdoor air and is thus evaporated into low-temperature, low-pressure gas refrigerant, which is discharged from the outdoor heat exchanger <NUM>. The low-temperature, low-pressure gas refrigerant discharged from the outdoor heat exchanger <NUM> is sucked into the compressor <NUM> again, where the gas refrigerant is compressed again and is discharged. The air-conditioning apparatus <NUM> repeatedly causes the refrigerant to circulate as above, thereby performing the heating operation of heating the indoor air.

Referring to <FIG>, how the air-conditioning apparatus <NUM> works in the cooling operation will now be described by following the flow of the refrigerant. First, low-temperature, low-pressure gas refrigerant is sucked into the compressor <NUM>, where the sucked refrigerant is compressed into high-temperature, high-pressure gas refrigerant. The high-temperature, high-pressure gas refrigerant resulting from the compression by the compressor <NUM> is discharged from the compressor <NUM>, flows through the flow switching device <NUM>, and then flows into the outdoor heat exchanger <NUM>. The high-temperature, high-pressure gas refrigerant having flowed into the outdoor heat exchanger <NUM> transfers heat to the air, supplied from the outdoor fan <NUM>, by exchanging heat with the air and is thus condensed into high-temperature, high-pressure liquid refrigerant, which is discharged from the outdoor heat exchanger <NUM>.

The liquid refrigerant discharged from the outdoor heat exchanger <NUM> is expanded and decompressed by the expansion device <NUM> into low-temperature, low-pressure two-phase gas-liquid refrigerant, which flows into the indoor heat exchanger <NUM>. The two-phase gas-liquid refrigerant having flowed into the indoor heat exchanger <NUM> receives heat from outdoor air, supplied from the indoor fan <NUM>, by exchanging heat with the outdoor air and is thus evaporated into low-temperature, low-pressure gas refrigerant, which is discharged from the indoor heat exchanger <NUM>. The low-temperature, low-pressure gas refrigerant discharged from the indoor heat exchanger <NUM> is sucked into the compressor <NUM> again, where the gas refrigerant is compressed again and is discharged. The air-conditioning apparatus <NUM> repeatedly causes the refrigerant to circulate as above, thereby performing the cooling operation of cooling the indoor air.

<FIG> schematically illustrates a configuration of the outdoor heat exchanger <NUM> according to Embodiment <NUM>. The arrows provided in <FIG> represent the direction of refrigerant flow. Referring now to <FIG>, the outdoor heat exchanger <NUM> according to Embodiment <NUM> will be described. In the following description, the outdoor heat exchanger <NUM> is regarded as a heat exchanger operating as an evaporator in the air-conditioning apparatus <NUM> performing the heating operation.

Note that the outdoor heat exchanger <NUM> may operate as a condenser in the cooling operation. When the outdoor heat exchanger <NUM> operates as a condenser, the direction of refrigerant flow illustrated in <FIG> is reversed. The configuration of the heat exchanger to be described below as the outdoor heat exchanger <NUM> may be replaced with the configuration of the indoor heat exchanger <NUM>. The outdoor heat exchanger <NUM> and the indoor heat exchanger <NUM> are each also simply referred to as heat exchanger.

As illustrated in <FIG>, the outdoor heat exchanger <NUM> includes a heat-exchanger core <NUM>, a liquid-header distributor <NUM>, and a gas-header distributor <NUM>. The liquid-header distributor <NUM> and the gas-header distributor <NUM> may each be referred to as header.

The heat-exchanger core <NUM> is configured to cause air around the heat-exchanger core <NUM> and the refrigerant flowing in the heat-exchanger core <NUM> to exchange heat with each other. The heat-exchanger core <NUM> is located between the liquid-header distributor <NUM> and the gas-header distributor <NUM>. The heat-exchanger core <NUM> includes a plurality of heat-transfer tubes <NUM>, which extend in a first direction (X-axis direction) and connect the liquid-header distributor <NUM> and the gas-header distributor <NUM> to each other; and a heat-transfer promoter <NUM>, which connect together the heat-transfer tubes <NUM> that are adjacent to one another.

In the heat-exchanger core <NUM>, each of the plurality of heat-transfer tubes <NUM> extends between the liquid-header distributor <NUM> and the gas-header distributor <NUM>. Each of the plurality of heat-transfer tubes <NUM> is in the form of a tube and allows the refrigerant to flow thereinside. The heat-transfer tube <NUM> allows the refrigerant inside the heat-transfer tube <NUM> and the air outside the heat-transfer tube <NUM> to exchange heat with each other. In the first direction (X-axis direction), each of the plurality of heat-transfer tubes <NUM> is connected at one end thereof to the gas-header distributor <NUM> and at the other end thereof to the liquid-header distributor <NUM>.

The plurality of heat-transfer tubes <NUM> are arranged at intervals from one another and in parallel with one another in the axial direction (Z-axis direction), that is, the elongated direction of the liquid-header distributor <NUM>. The plurality of heat-transfer tubes <NUM> are arranged at intervals from one another in the top-bottom direction. In other words, the plurality of heat-transfer tubes <NUM> are arranged at intervals from one another in a refrigerant-flow direction coinciding with the longitudinal direction of the liquid-header distributor <NUM> and the gas-header distributor <NUM>, and are each connected to the liquid-header distributor <NUM> and to the gas-header distributor <NUM>. Adjacent ones of the plurality of heat-transfer tubes <NUM> are oriented face to face with each other. Between each adjacent two of the plurality of heat-transfer tubes <NUM> is provided a gap serving as an air passageway.

In the outdoor heat exchanger <NUM>, the elongated direction of the plurality of heat-transfer tubes <NUM> is referred to as the first direction and is a horizontal direction. Note that the elongated direction of the plurality of heat-transfer tubes <NUM> that is referred to as the first direction is not limited to a horizontal direction and may be a direction inclined relative to the horizontal direction. In the outdoor heat exchanger <NUM>, the direction of arrangement of the plurality of heat-transfer tubes <NUM> is referred to as a second direction and is the vertical direction. Note that the direction of arrangement of the plurality of heat-transfer tubes <NUM> is not limited to the vertical direction and may be a direction inclined relative to the vertical direction.

The heat-transfer tubes <NUM> are each, for example, a circular tube forming a passageway having a circular cross section, or a tube forming a passageway having an oval cross section. Alternatively, the heat-transfer tubes <NUM> may each be a flat tube forming a passageway having a flat cross section, and the passageway provided thereinside includes a plurality of passageways. The heat-transfer tubes <NUM> illustrated in <FIG> are linear heat-transfer tubes <NUM> each having no U-shaped folded portion, that is, a portion where the refrigerant passageway is folded to extend in a direction other than the horizontal direction. The heat-transfer tubes <NUM> are not limited to such linear heat-transfer tubes <NUM> and may each have a U-shaped folded portion where the refrigerant passageway is folded to extend in a direction other than the horizontal direction.

The heat-exchanger core <NUM> may include one or more rows of stacked heat-transfer tubes <NUM> in a horizontal direction. The horizontal direction is orthogonal to the direction in which the heat-transfer tubes <NUM> extends. In other words, there may be rows of the heat-transfer tubes <NUM> stack in the Y-axis direction (not illustrated) that is orthogonal both to the X-axis direction and the Z-axis direction indicated in <FIG>.

The heat-transfer promoter <NUM> is intended to improve the efficiency of heat exchange between the air and the refrigerant. The plurality of heat-transfer tubes <NUM> that are adjacent to one another are connected to one another by the heat-transfer promoter <NUM>. The heat-transfer promoter <NUM> is, for example, one or more members in the form of plates. The heat-transfer promoter <NUM> is, for example, a plate fin or a corrugated fin. The shape of the heat-transfer promoter <NUM> is not limited and may be a flat shape or a corrugated shape.

The heat-exchanger core <NUM> includes a plurality of heat-transfer promoters <NUM> arranged at intervals from one another and in parallel with one another in the elongated direction of the heat-transfer tubes <NUM> (the X-axis direction). If the heat-transfer promoters <NUM> are plate fins, each of the plurality of heat-transfer tubes <NUM> extends through the plurality of heat-transfer promoters <NUM>.

The heat-exchanger core <NUM> is not limited to the one including the heat-transfer tubes <NUM> and the heat-transfer promoter <NUM>. For example, the heat-exchanger core <NUM> may include a plurality of heat-transfer tubes <NUM> but no heat-transfer promoter <NUM> that connects the adjacent heat-transfer tubes <NUM> to one another.

The gas-header distributor <NUM> is connected to the ends of the plurality of heat-transfer tubes <NUM> on one side in the elongated direction (X-axis direction). The gas-header distributor <NUM> is connected to the heat-transfer tubes <NUM> of the heat-exchanger core <NUM> such that the inside of the gas-header distributor <NUM> communicates with the inside of each of the heat-transfer tubes <NUM>. The gas-header distributor <NUM> extends in the direction of arrangement of the plurality of heat-transfer tubes <NUM> (the Z-axis direction).

In the outdoor heat exchanger <NUM>, the gas-header distributor <NUM> serves as a merging mechanism where portions of the refrigerant that are discharged from the plurality of heat-transfer tubes <NUM> of the heat-exchanger core <NUM> merge together. When the outdoor heat exchanger <NUM> operates as an evaporator, a flow of gas-phase refrigerant occurs in the gas-header distributor <NUM>. Specifically, the gas-header distributor <NUM> allows gas-phase refrigerant to flow from the upper side toward the lower side.

The gas-header distributor <NUM> includes a body 60a, to which the heat-transfer tubes <NUM> are connected; and a gas-header inflow/outflow pipe <NUM>, which is connected to the body 60a. The body 60a is a long cylindrical member having two closed ends, with a space provided thereinside. The body 60a is formed of a pipe that is thicker than the heat-transfer tubes <NUM>. The gas-header distributor <NUM> is installed such that the center axis thereof in the longitudinal direction (Z-axis direction) extends in the vertical direction or is inclined within such an angle as to have a vertical vector component. The body 60a has thereinside a space through which the refrigerant is to flow.

The gas-header inflow/outflow pipe <NUM> is intended to allow the refrigerant discharged from the plurality of heat-transfer tubes <NUM> and merged together to be discharge from the outdoor heat exchanger <NUM>. The gas-header inflow/outflow pipe <NUM> is horizontally connected to the body 60a of the gas-header distributor <NUM>. Alternatively, the gas-header inflow/outflow pipe <NUM> may be vertically connected to the body 60a of the gas-header distributor <NUM>. Moreover, the gas-header inflow/outflow pipe <NUM> may be connected to the body 60a of the gas-header distributor <NUM> in a direction toward the far side or near side of the plane of the page or in any other direction. While <FIG> illustrates a case where one gas-header inflow/outflow pipe <NUM> is connected to the body 60a of the gas-header distributor <NUM>, the number of gas-header inflow/outflow pipes <NUM> to be connected to the body 60a is not limited to one and may be two or more.

The liquid-header distributor <NUM> allows refrigerant to flow thereinside. The liquid-header distributor <NUM> is in the form of a long pipe elongated in the top-bottom direction. The liquid-header distributor <NUM> is connected to the ends of the plurality of heat-transfer tubes <NUM> on the other side in the elongated direction (X-axis direction). The liquid-header distributor <NUM> is located across the plurality of heat-transfer tubes <NUM> from the gas-header distributor <NUM>. The liquid-header distributor <NUM> is connected to the heat-transfer tubes <NUM> of the heat-exchanger core <NUM> such that the inside of the liquid-header distributor <NUM> communicates with the inside of each of the heat-transfer tubes <NUM>. The liquid-header distributor <NUM> extends in the direction of arrangement of the plurality of heat-transfer tubes <NUM> (the Z-axis direction).

The liquid-header distributor <NUM> distributes the refrigerant to the plurality of heat-transfer tubes <NUM>. In the outdoor heat exchanger <NUM>, the liquid-header distributor <NUM> serve as a distributing mechanism through which the refrigerant to be received by the heat-exchanger core <NUM> is distributed among the plurality of heat-transfer tubes <NUM>. When the outdoor heat exchanger <NUM> operates as an evaporator, an upward flow of two-phase gas-liquid refrigerant occurs in the liquid-header distributor <NUM>. Specifically, the liquid-header distributor <NUM> allows two-phase gas-liquid refrigerant to flow from the lower side toward the upper side. When the outdoor heat exchanger <NUM> operates as an evaporator, the two-phase gas-liquid refrigerant passes through an orifice <NUM> from the lower side toward the upper side.

The liquid-header distributor <NUM> is installed such that the center axis thereof in the longitudinal direction (Z-axis direction) extends in the vertical direction or is inclined within such an angle as to have a vertical vector component. The liquid-header distributor <NUM> includes a body 70a, to which the heat-transfer tubes <NUM> are connected; and a liquid-header inflow/outflow pipe <NUM>, which is connected to the body 70a. Details of the liquid-header distributor <NUM> will be described separately below.

An operation of the outdoor heat exchanger <NUM> according to Embodiment <NUM> will now be described, by taking an exemplary case where the outdoor heat exchanger <NUM> serves as an evaporator of the air-conditioning apparatus <NUM>. The outdoor heat exchanger <NUM> serving as an evaporator receives the two-phase gas-liquid refrigerant resulting from the decompression by the expansion device <NUM>. The two-phase gas-liquid refrigerant received by the outdoor heat exchanger <NUM> flows through the inside of the body 70a of the liquid-header distributor <NUM> in the longitudinal direction of the body 70a and is sequentially distributed to the plurality of heat-transfer tubes <NUM>.

The liquid-header distributor <NUM> mainly distributes the two-phase gas-liquid refrigerant, which contains liquid, to the plurality of heat-transfer tubes <NUM>. In this process, the refrigerant flowing from the liquid-header distributor <NUM> of the outdoor heat exchanger <NUM> into the plurality of heat-transfer tubes <NUM> receives heat while flowing through the passageways provided in the plurality of heat-transfer tubes <NUM> and thus evaporates. Portions of the gas-phase refrigerant resulting from the evaporation occurred in the plurality of heat-transfer tubes <NUM> merge together in the gas-header distributor <NUM>. The merged gas-phase refrigerant is discharged from the gas-header distributor <NUM> through the gas-header inflow/outflow pipe <NUM>, and is sucked into the compressor <NUM> via the flow switching device <NUM>.

<FIG> outlines the liquid-header distributor <NUM> according to Embodiment <NUM>. <FIG> illustrates a section of the liquid-header distributor <NUM> illustrated in <FIG>, taken along line A-A perpendicular to the direction in which the body 70a thereof extends. The section taken along line A-A is a plane perpendicular to the axial direction of the liquid-header distributor <NUM>. The section taken along line A-A is also regarded as a diagram illustrating a projection of the plurality of heat-transfer tubes <NUM> and a projection of an internal space <NUM>, to be described below, that are obtained by projecting the plurality of heat-transfer tubes <NUM> and a part defined as the internal space <NUM> onto a plane perpendicular to the axial direction of the liquid-header distributor <NUM>.

In <FIG>, the X-axis direction is the direction in which the heat-transfer tubes <NUM> extend, and the Z-axis direction is the direction in which the body 70a of the liquid-header distributor <NUM> extends. The Z-axis direction is also regarded as the direction of arrangement of the heat-transfer tubes <NUM>. In <FIG>, the Y-axis direction is a direction perpendicular to the X-axis direction and to the Z-axis direction. Referring to <FIG>, the liquid-header distributor <NUM> will further be described. The liquid-header distributor <NUM> includes the body 70a and the liquid-header inflow/outflow pipe <NUM> attached to the body 70a as described above, and further includes an orifice plate <NUM>.

The body 70a is a long cylindrical member having two closed ends, with a space through which refrigerant is to flow provided thereinside. The body 70a is formed of a pipe that is thicker than the heat-transfer tubes <NUM>. While the body 70a of the liquid-header distributor <NUM> illustrated in <FIG> has a circular shape in a section perpendicular to the longitudinal direction thereof, the shape of the section of the body 70a is not limited to a circular shape and may be an oval or rectangular shape. The shape of the section of the body 70a is not limited to a particular shape.

The body 70a may have an appearance of a circular column or a polygonal column. The body 70a is installed such that the center axis thereof in the longitudinal direction (Z-axis direction) extends in the vertical direction or is inclined within such an angle as to have a vertical vector component. The body 70a has an inlet <NUM>, connection ports <NUM>, and the internal space <NUM>.

The inlet <NUM> is a through-hole provided in the body 70a. The inlet <NUM> receives the liquid-header inflow/outflow pipe <NUM> connected thereto. The refrigerant flowing from the liquid-header inflow/outflow pipe <NUM> flows into the inlet <NUM>. As illustrated in <FIG>, for example, the liquid-header inflow/outflow pipe <NUM> is connected to a part of the lateral face of the body 70a that is located opposite a part to which the heat-transfer tubes <NUM> are connected. Th position of the inlet <NUM> and the position of connection of the liquid-header inflow/outflow pipe <NUM> are not limited to the part of the lateral face of the body 70a that is opposite the part to which the heat-transfer tubes <NUM> are connected.

As illustrated in <FIG>, the inlet <NUM> is located below one of the plurality of heat-transfer tubes <NUM> that is at the lowest position in the body 70a. The position of the inlet <NUM> is not limited to the above. The inlet <NUM> may be provided face to face with the one of the plurality of heat-transfer tubes <NUM> that is at the lowest position in the body 70a.

The connection ports <NUM> are a plurality of through-holes provided in the body 70a and are arrayed in the longitudinal direction of the body 70a (the Z-axis direction). The plurality of connection ports <NUM> provided in the body 70a are arranged at intervals from one another in the top-bottom direction and receive the plurality of heat-transfer tubes <NUM> that are fitted thereto. The heat-transfer tubes <NUM> fitted to the connection ports <NUM> pierce through the wall of the body 70a. The heat-transfer tubes <NUM> fitted to the connection ports <NUM> are held by the lateral wall of the body 70a.

The plurality of heat-transfer tubes <NUM> connected to the body 70a of the liquid-header distributor <NUM> each have an end 50a, which sticks out into the internal space <NUM> of the liquid-header distributor <NUM>. Now, assume that the part of the liquid-header distributor <NUM> that is defined as the internal space <NUM> and the plurality of heat-transfer tubes <NUM> are projected on a plane perpendicular to the axial direction of the liquid-header distributor <NUM>. The heat-transfer tubes <NUM> connected to the body 70a stick out into the internal space <NUM> of the liquid-header distributor <NUM> such that the area of projection of the heat-transfer tubes <NUM> is equal to or greater than half the area of projection of the part of the liquid-header distributor <NUM> that is defined as the internal space <NUM>. In other words, when the part of the liquid-header distributor <NUM> that is defined as the internal space <NUM> and the plurality of heat-transfer tubes <NUM> are projected on a plane perpendicular to the axial direction of the liquid-header distributor <NUM>, the plurality of heat-transfer tubes <NUM> occupies one-half or greater of the part defined as the internal space <NUM>.

The internal space <NUM> communicates with the spaces inside the heat-transfer tubes <NUM> and with the space inside the liquid-header inflow/outflow pipe <NUM>, so that the refrigerant flowing from the liquid-header inflow/outflow pipe <NUM> through the inlet <NUM> flows upward in the internal space <NUM>.

The body 70a is provided with the liquid-header inflow/outflow pipe <NUM>. The liquid-header inflow/outflow pipe <NUM> serves a refrigerant inflow pipe through which the refrigerant flows into the liquid-header distributor <NUM>. The liquid-header inflow/outflow pipe <NUM> communicates with the internal space <NUM> of the body 70a. The liquid-header inflow/outflow pipe <NUM> is intended to allow the refrigerant to be distributed to the plurality of heat-transfer tubes <NUM> to flow into the outdoor heat exchanger <NUM>. When the outdoor heat exchanger <NUM> serves as an evaporator, the two-phase gas-liquid refrigerant to be received by the internal space <NUM> of the body 70a flows from the outside of the outdoor heat exchanger <NUM> into the internal space <NUM> of the body 70a through the liquid-header inflow/outflow pipe <NUM>.

The liquid-header inflow/outflow pipe <NUM> is connected to the liquid-header distributor <NUM> at a position below the lowest one of the plurality of heat-transfer tubes <NUM>. Desirably, the liquid-header inflow/outflow pipe <NUM> may be provided at such a position as to allow the two-phase gas-liquid refrigerant to flow into a space below the lowest one of the heat-transfer tubes <NUM> and in such a manner as to extend in the direction in which the heat-transfer tubes <NUM> extend (the X-axis direction). The position of connection of the liquid-header inflow/outflow pipe <NUM> is not limited to the above. For example, the liquid-header inflow/outflow pipe <NUM> may be positioned face to face with the lowest one of the heat-transfer tubes <NUM> in the internal space <NUM>.

If the liquid-header inflow/outflow pipe <NUM> is provided at a position between adjacent ones of the heat-transfer tubes <NUM> in the internal space <NUM>, an upward refrigerant flow and a downward refrigerant flow are generated, with the speed of the upward flow of the two-phase gas-liquid refrigerant being reduced. Such a reduction in the speed of the upward flow of the two-phase gas-liquid refrigerant increases the probability of separation between the gas refrigerant and the liquid refrigerant. Therefore, the liquid-header inflow/outflow pipe <NUM> may desirably be provided at the position defined above.

While <FIG> illustrates a case where the liquid-header inflow/outflow pipe <NUM> is horizontally connected to the body 70a of the liquid-header distributor <NUM>, the liquid-header inflow/outflow pipe <NUM> may be vertically connected to the body 70a of the liquid-header distributor <NUM>. Moreover, the liquid-header inflow/outflow pipe <NUM> may be connected to the body 70a of the liquid-header distributor <NUM> in a direction toward the far side or near side of the plane of the page or in any other direction. While <FIG> illustrates a case where one liquid-header inflow/outflow pipe <NUM> is connected to the body 70a of the liquid-header distributor <NUM>, the number of liquid-header inflow/outflow pipes <NUM> to be connected to the body 70a is not limited to one and may be two or more.

The liquid-header distributor <NUM> includes an orifice plate <NUM>, which is in the form of a plate and is provided inside the body 70a. The orifice plate <NUM> is a partition that divides the internal space <NUM> of the body 70a in the top-bottom direction (Z-axis direction). The liquid-header distributor <NUM> includes one or more orifice plates <NUM> in an area above one of the heat-transfer tubes <NUM> that is closest to the liquid-header inflow/outflow pipe <NUM>. In short, the orifice plate <NUM> is located above the lowest one of the plurality of heat-transfer tubes <NUM> in the internal space <NUM>.

More specifically, letting the number of heat-transfer tubes <NUM> arranged in parallel with one another in the top-bottom direction be n, the orifice plate <NUM> is located below an n/<NUM>-th one of the heat-transfer tubes <NUM> counting from the bottom.

The body 70a is provided with the orifice plate <NUM> in the internal space <NUM> thereof. The internal space <NUM> is divided by the orifice plate <NUM> into a top space 78a and a bottom space 78b. In the internal space <NUM> of the body 70a, the top space 78a is a space above the orifice plate <NUM>, and the bottom space 78b is a space below the orifice plate <NUM>.

As illustrated in <FIG>, the orifice plate <NUM> has an orifice <NUM>. The orifice <NUM> is a through-hole provided in the orifice plate <NUM> and through which the spaces above and below the orifice plate <NUM> communicate with each other. The opening area of the orifice <NUM> is smaller than the sectional area of the internal space <NUM> in a plane perpendicular to the axial direction of the liquid-header distributor <NUM>.

The orifice <NUM> is provided at such a position that when the orifice <NUM> and the plurality of heat-transfer tubes <NUM> are projected on a plane perpendicular to the axial direction of the liquid-header distributor <NUM>, one-half or greater of the opening area of the orifice <NUM> does not coincide with the plurality of heat-transfer tubes <NUM>. Alternatively, the orifice <NUM> is provided at such a position that when the orifice <NUM> and the plurality of heat-transfer tubes <NUM> are projected on a plane perpendicular to the axial direction of the liquid-header distributor <NUM>, the orifice <NUM> does not coincide with the plurality of heat-transfer tubes <NUM>.

As illustrated in <FIG>, in a plane perpendicular to the axial direction of the liquid-header distributor <NUM>, the orifice <NUM> may be shaped as an oblong hole, a slit, or any other opening that is elongated in the longitudinal direction of the end 50a of each flat heat-transfer tube <NUM>. The longitudinal direction of the end 50a of the heat-transfer tube <NUM> is, for example, a horizontal direction (the Y-axis direction) orthogonal to the direction in which the heat-transfer tube <NUM> extends. The orifice <NUM> may be one of two or more holes arranged side by side at intervals in the longitudinal direction of the end 50a of the heat-transfer tube <NUM>.

In a part where the heat-transfer tube <NUM> is fitted to the liquid-header distributor <NUM>, the sectional shape of an area where the refrigerant passes is elongated in the longitudinal direction of the end 50a of the heat-transfer tube <NUM>. Therefore, in a plane perpendicular to the axial direction of the liquid-header distributor <NUM>, the orifice <NUM> may desirably be shaped such that an opening length L1, defined in a direction perpendicular to the direction in which the heat-transfer tube <NUM> extends, is substantially greater than an opening length L2, defined in the direction in which the heat-transfer tube <NUM> extends.

In the internal space <NUM> of the body 70a, the top space 78a and the bottom space 78b communicate with each other through the orifice <NUM> provided in the orifice plate <NUM>. In the body 70a, the refrigerant flows through the orifice <NUM> provided in the orifice plate <NUM>. When the outdoor heat exchanger <NUM> operates as an evaporator, the two-phase gas-liquid refrigerant flows through the orifice <NUM> from the lower side toward the upper side, that is, the two-phase gas-liquid refrigerant moves from the bottom space 78b to the top space 78a through the orifice <NUM>.

The liquid-header distributor <NUM> includes one or more orifice plates <NUM> in an area above one of the heat-transfer tubes <NUM> that is closest to the liquid-header inflow/outflow pipe <NUM>. Each orifice plate <NUM> has the orifice <NUM>. In the outdoor heat exchanger <NUM> configured as above, the two-phase gas-liquid refrigerant is evenly distributed from the liquid-header distributor <NUM> sequentially to the plurality of heat-transfer tubes <NUM>. Such a functional effect produced by the outdoor heat exchanger <NUM> will now be described in detail.

<FIG> schematically illustrates a liquid-header distributor <NUM> according to Comparative Embodiment, which includes no orifice plate <NUM> thereinside, and specifically illustrates how two-phase gas-liquid refrigerant flows in the liquid-header distributor <NUM> when the outdoor heat exchanger <NUM> operates as an evaporator. <FIG> conceptually illustrates a section of the liquid-header distributor <NUM> illustrated in <FIG>, taken along line B-B perpendicular to a direction in which the liquid-header distributor <NUM> extends.

In <FIG>, the chart to the left of the liquid-header distributor <NUM> illustrates the flow-speed distribution versus the height of a lateral-blow housing, such as the one with the liquid-header distributor <NUM>. The lateral-blow housing refers to a heat exchanger in which air flows in a horizontal direction (the Y-axis direction) orthogonal to the direction in which the heat-transfer tubes <NUM> mainly extend. In general, as illustrated in <FIG>, the flow speed in the liquid-header distributor <NUM> of the lateral-blow housing is high in an area at a middle height but decreases in the height direction toward the lower and upper ends.

The two-phase gas-liquid refrigerant having flowed from the liquid-header inflow/outflow pipe <NUM> into the liquid-header distributor <NUM> is sequentially distributed to the plurality of heat-transfer tubes <NUM> while being affected by gravity. The liquid-phase refrigerant contained in the two-phase gas-liquid refrigerant flowing in the liquid-header distributor <NUM> has a higher density than the gas-phase refrigerant and is therefore greatly affected by gravity. Accordingly, when the refrigerant flow rate is low, a large amount of liquid refrigerant tends to flow into those heat-transfer tubes <NUM> that are connected to a lower part of the liquid-header distributor <NUM>. On the other hand, if the refrigerant flow rate is high, a large amount of liquid refrigerant tends to flow into those heat-transfer tubes <NUM> that are connected to an upper part of the liquid-header distributor <NUM>. That is, the distribution of liquid refrigerant among the plurality of heat-transfer tubes <NUM> is greatly affected by the change in the refrigerant flow rate.

In particular, at a low refrigerant flow rate, while some portion of the liquid refrigerant is blown upward, some other portion of the liquid refrigerant is pulled downward by gravity. Consequently, a large portion of the liquid refrigerant tends to flow into those heat-transfer tubes <NUM> that are connected to a lower part of the liquid-header distributor <NUM>. Hence, in the heat exchanger including the liquid-header distributor <NUM> according to Comparative Embodiment, the amount of liquid refrigerant that flows through the heat-transfer tubes <NUM> is smaller in an area where the flow speed is higher but is greater in an area where the flow speed is lower. Such a phenomenon deteriorates the performance of the heat exchanger. That is, the liquid-header distributor <NUM> according to Comparative Embodiment cannot handle a wide range of refrigerant flow rate.

<FIG> schematically illustrates the liquid-header distributor <NUM> according to Embodiment <NUM>, and specifically illustrates how two-phase gas-liquid refrigerant flows in the liquid-header distributor <NUM> when the outdoor heat exchanger <NUM> operates as an evaporator. <FIG> illustrates a section of the liquid-header distributor <NUM> illustrated in <FIG>, taken along line A-A perpendicular to the direction in which the body 70a thereof extends.

Some portion of the two-phase gas-liquid refrigerant having flowed from the liquid-header inflow/outflow pipe <NUM> into the liquid-header distributor <NUM> is sequentially distributed to the plurality of heat-transfer tubes <NUM> while being affected by gravity. Some portion of the two-phase gas-liquid refrigerant having flowed from the liquid-header inflow/outflow pipe <NUM> into the liquid-header distributor <NUM> is sequentially distributed to the plurality of heat-transfer tubes <NUM> while gathering the speed thereof by passing through the orifice <NUM> but being affected by gravity.

Since the refrigerant gathers the speed thereof by passing through the orifice <NUM>, the liquid refrigerant reaches an upper part of the liquid-header distributor <NUM>. Thus, in the liquid-header distributor <NUM> including the orifice plate <NUM>, when the refrigerant flow rate is low, a greater amount of liquid refrigerant flows into those heat-transfer tubes <NUM> that are connected to an upper part of the liquid-header distributor <NUM> than in the liquid-header distributor <NUM> according to Comparative Embodiment including no orifice plate <NUM>.

Furthermore, when the refrigerant flow rate is low, some of the liquid refrigerant in the liquid-header distributor <NUM> that is pulled downward by gravity is received by the orifice plate <NUM> spreading around the orifice <NUM> and is less likely to fall below the orifice plate <NUM>. Moreover, the liquid refrigerant received by the orifice plate <NUM> spreading around the orifice <NUM> is dragged by the refrigerant passing through the orifice <NUM> at an increased speed and thus flows toward an upper part of the liquid-header distributor <NUM>.

Such a configuration of the outdoor heat exchanger <NUM> facilitates the flow of the liquid refrigerant into those heat-transfer tubes <NUM> that are connected to a part of the liquid-header distributor <NUM> that is above the orifice plate <NUM>. Hence, in the outdoor heat exchanger <NUM>, the amount of liquid refrigerant that flows through the heat-transfer tubes <NUM> is greater in an area where the flow speed is higher and is smaller in an area where the flow speed is lower. Thus, the performance of the heat exchanger is improved. In the outdoor heat exchanger <NUM>, the orifice <NUM> provided inside the liquid-header distributor <NUM> facilitates the flow of the liquid refrigerant toward an upper part of the liquid-header distributor <NUM> and thus suppresses the gathering of the liquid refrigerant in a lower part of the liquid-header distributor <NUM>, whereby the performance of the heat exchanger is improved.

The orifice <NUM> is provided at such a position that when the orifice <NUM> and the plurality of heat-transfer tubes <NUM> are projected on a plane perpendicular to the axial direction of the liquid-header distributor <NUM>, one-half or greater of the opening area of the orifice <NUM> does not coincide with the plurality of heat-transfer tubes <NUM>. Since the liquid-header distributor <NUM> has the orifice <NUM> at such a position, the momentum of the liquid refrigerant having gathered the speed thereof at the orifice <NUM> is less likely to be reduced by the presence of the plurality of heat-transfer tubes <NUM>.

The orifice <NUM> is provided at such a position that when the orifice <NUM> and the plurality of heat-transfer tubes <NUM> are projected on a plane perpendicular to the axial direction of the liquid-header distributor <NUM>, the orifice <NUM> does not coincide with the plurality of heat-transfer tubes <NUM>. Since the liquid-header distributor <NUM> has the orifice <NUM> at such a position, the momentum of the liquid refrigerant having gathered the speed thereof at the orifice <NUM> is not reduced by the presence of the plurality of heat-transfer tubes <NUM>.

Letting the number of heat-transfer tubes <NUM> arranged in parallel with one another in the top-bottom direction be n, the orifice plate <NUM> is located below an n/<NUM>-th one of the heat-transfer tubes <NUM> counting from the bottom. That is, the liquid refrigerant in the liquid-header distributor <NUM> gathers the flow speed thereof at a position where the flow speed of the liquid refrigerant is relatively high. Accordingly, a greater effect of speed increase is produced than in a case where the orifice plate <NUM> is not provided at the position defined above. Such a configuration of the outdoor heat exchanger <NUM> facilitates the flow of the liquid refrigerant toward an upper part of the liquid-header distributor <NUM> and thus suppresses the gathering of the liquid refrigerant in a lower part of the liquid-header distributor <NUM>, whereby the performance of the heat exchanger is improved.

The orifice plate <NUM> may have two or more orifices <NUM>. If the orifice plate <NUM> has two or more orifices <NUM>, the flow of the liquid refrigerant having passed through the orifices <NUM> becomes more even in the liquid-header distributor <NUM> than in the case of one orifice <NUM>. Furthermore, in a case where the distribution of the liquid refrigerant in the liquid-header distributor <NUM> in a Y-X plane is uneven in an area below the orifice plate <NUM>, the effect of increasing the speed of the liquid refrigerant that is produced when the liquid refrigerant passes through the orifice <NUM> is less likely to be reduced. Specifically, in a case where the flow rate of the refrigerant is variable or the gas-liquid ratio is variable, since the gathering of the liquid refrigerant in a lower part of the liquid-header distributor <NUM> is suppressed, the deterioration in the performance of the heat exchanger is suppressed. Even in a case of different physical properties or different other characteristics, since the gathering of the liquid refrigerant in a lower part of the liquid-header distributor <NUM> is suppressed, the deterioration in the performance of the heat exchanger is suppressed.

<FIG> outlines a liquid-header distributor <NUM> according to Embodiment <NUM>. <FIG> illustrates a section of the liquid-header distributor <NUM> illustrated in <FIG>, taken along line A-A perpendicular to a direction in which a body 70a thereof extends. <FIG> illustrates a section of the liquid-header distributor <NUM> illustrated in <FIG>, taken along line C-C perpendicular to the direction in which the body 70a thereof extends. Elements having the same functions and effects as those such as the liquid-header distributor <NUM> and other elements according to Embodiment <NUM> are denoted by corresponding ones of the reference signs, and description of such elements is omitted. The liquid-header distributor <NUM> according to Embodiment <NUM> will be described for specifying the position of the orifice <NUM>.

As illustrated in <FIG>, the orifice plate <NUM> provided inside the liquid-header distributor <NUM> has an orifice <NUM>, which is in contact with an inner wall, 70b, of the body 70a forming the liquid-header distributor <NUM>. Specifically, in the internal space <NUM> of the body 70a, the orifice <NUM> that allows the top space 78a and the bottom space 78b to communicate with each other is defined by an edge, 71a, of the orifice plate <NUM> and the inner wall 70b of the body 70a. In other words, a part of the inner wall of the orifice <NUM> is formed by an inner wall, 70b1, of the liquid-header distributor <NUM>.

In a plane perpendicular to the axial direction of the liquid-header distributor <NUM>, the edge 71a of the orifice plate <NUM> is recessed toward the center of the orifice plate <NUM> relative to an edge 71b, which adjoins the edge 71a in the peripheral direction. The edge 71a of the orifice plate <NUM> is spaced apart from the inner wall 70b of the body 70a, whereas the edge 71b of the orifice plate <NUM> is in contact with the inner wall 70b of the body 70a.

A part of the orifice <NUM> is defined by the inner wall 70b1, which forms a part of the surface of the liquid-header distributor <NUM> that is opposite a part where the plurality of heat-transfer tubes <NUM> are connected. Desirably, the inner wall 70b1 that defines the orifice <NUM> may be a wall portion located above the inlet <NUM>. However, the inner wall 70b that defines the orifice <NUM> is not limited to a wall portion located above the inlet <NUM>.

When the outdoor heat exchanger <NUM> operates as an evaporator, the refrigerant having passed through the liquid-header inflow/outflow pipe <NUM> flows into the liquid-header distributor <NUM> and is sequentially distributed to the plurality of heat-transfer tubes <NUM> while flowing upward in the liquid-header distributor <NUM>. In this process, in a section of the liquid-header distributor <NUM> that is perpendicular to the longitudinal direction and located below the orifice plate <NUM>, that is, in the section illustrated in <FIG> that is taken along line C-C, the liquid refrigerant flows upward along a part of the inner wall 70b of the liquid-header distributor <NUM> that is located above the liquid-header inflow/outflow pipe <NUM>. On the other hand, the gas refrigerant flows through an area of the liquid-header distributor <NUM> that is on the inner side relative to the flow of the liquid refrigerant.

In the liquid-header distributor <NUM> according to Embodiment <NUM>, the orifice <NUM> is in contact with the inner wall 70b of the body 70a forming the liquid-header distributor <NUM>. Furthermore, a part of the orifice <NUM> is defined by the inner wall 70b1, which forms a part of the surface of the liquid-header distributor <NUM> that is opposite a part where the plurality of heat-transfer tubes <NUM> are connected. In short, the orifice <NUM> is defined by the edge 71a of the orifice plate <NUM> and the inner wall 70b1 of the liquid-header distributor <NUM>. A part of the inner wall of the orifice <NUM> is formed by the inner wall 70b1 of the liquid-header distributor <NUM>.

In the liquid-header distributor <NUM> configured as above, an area in the body 70a where the liquid refrigerant flowing upward in the liquid-header distributor <NUM> is present overlaps the projection of the orifice <NUM> on the section taken along line B-B. Therefore, the upward flow of the liquid refrigerant in the liquid-header distributor <NUM> is not hindered by the orifice plate <NUM> having the orifice <NUM>. Therefore, an increased amount of liquid refrigerant flows upward. In the outdoor heat exchanger <NUM>, the liquid refrigerant more easily passes through the orifice <NUM> than in a case where the orifice <NUM> is not provided at the position defined above. Accordingly, the liquid refrigerant more easily flows into those heat-transfer tubes <NUM> that are connected to an upper part of the liquid-header distributor <NUM>, whereby the performance of the heat exchanger is further improved.

<FIG> outlines a first modification of the liquid-header distributor <NUM> according to Embodiment <NUM>. <FIG> illustrates a section of the liquid-header distributor <NUM> illustrated in <FIG>, taken along line A-A perpendicular to the direction in which the body 70a thereof extends. The first modification of the liquid-header distributor <NUM> according to Embodiment <NUM> will be described for specifying the shape of the orifice <NUM> of the liquid-header distributor <NUM> according to Embodiment <NUM>.

The orifice <NUM> of the liquid-header distributor <NUM> described in Embodiment <NUM> is shaped as an oblong hole or any other opening. Likewise, the orifice <NUM> of the liquid-header distributor <NUM> described in Embodiment <NUM> may desirably be an oblong hole, with a part of the edge of the orifice <NUM> being formed by a part of the inner wall 70b of the liquid-header distributor <NUM> that faces toward the tips of the heat-transfer tubes <NUM> and is continuous with the orifice <NUM>. The orifice <NUM> defined by the orifice plate <NUM> and the inner wall 70b1 of the body 70a may desirably be an oblong hole whose opening size is greater in a horizontal direction, specifically, the Y-axis direction represented in <FIG>, orthogonal to the direction in which the heat-transfer tubes <NUM> extend. For example, as illustrated in <FIG>, in a plane perpendicular to the axial direction of the liquid-header distributor <NUM>, the orifice <NUM> may have a semicircular shape defined by an arc-shaped inner wall 70b1 and a linear edge 71a.

<FIG> outlines a second modification of the liquid-header distributor <NUM> according to Embodiment <NUM>. <FIG> illustrates a section of the liquid-header distributor <NUM> illustrated in <FIG>, taken along line A-A perpendicular to the direction in which the body 70a thereof extends. The orifice <NUM> defined by the orifice plate <NUM> and the inner wall 70b1 of the body 70a is not limited to an oblong hole. The orifice <NUM> defined by the orifice plate <NUM> and the inner wall 70b1 of the body 70a may be a circular hole.

Even if the orifice <NUM> is a circular hole, since a part of the orifice <NUM> is defined by the inner wall 70b1 of the body 70a, the liquid refrigerant flows upward in the liquid-header distributor <NUM> along the inner wall 70b1 that extends continuously in the top-bottom direction. Therefore, the outdoor heat exchanger <NUM> including the liquid-header distributor <NUM> configured as above produces an effect of causing the liquid refrigerant to flow upward.

While <FIG> illustrate a case where only one orifice <NUM> is provided by utilizing the inner wall 70b of the body 70a, the number of orifices <NUM> is not limited to one. Two or more orifices <NUM> may be provided by utilizing the inner wall 70b of the body 70a.

<FIG> outlines a first example of a liquid-header distributor <NUM> according to Embodiment <NUM>. <FIG> illustrates a section of the liquid-header distributor <NUM> illustrated in <FIG>, taken along line A-A perpendicular to a direction in which a body 70a thereof extends. Elements having the same functions and effects as those such as the liquid-header distributor <NUM> and other elements according to Embodiment <NUM> or <NUM> are denoted by corresponding ones of the reference signs, and description of such elements is omitted. The liquid-header distributor <NUM> according to Embodiment <NUM> will be described for specifying the shape of the orifice plate <NUM>.

The orifice plate <NUM> has a top face 71d, which is inclined downward toward the orifice <NUM> when the orifice plate <NUM> is seen in a section taken in the axial direction of the liquid-header distributor <NUM> as illustrated in <FIG>. Specifically, the orifice plate <NUM> is inclined in such a direction that the center of gravity of the orifice <NUM> in the section is at a lower position of the orifice plate <NUM>. The top face 71d of the orifice plate <NUM> is recessed in an oblique circular conical shape at the deepest part of which the orifice <NUM> is provided. In other words, the top face 71d of the orifice plate <NUM> forms a conical shape at the deepest part of which the orifice <NUM> is provided. The top face 71d of the orifice plate <NUM> forms a surface of the orifice plate <NUM> that defines the top space 78a.

<FIG> outlines a second example of the liquid-header distributor <NUM> according to Embodiment <NUM>. <FIG> illustrates a section of the liquid-header distributor <NUM> illustrated in <FIG>, taken along line A-A. As illustrated in <FIG>, the orifice plate <NUM> having the orifice <NUM> is inclined downward toward a part of the surface of the liquid-header distributor <NUM> that is opposite a part where the plurality of heat-transfer tubes <NUM> are connected. In other words, the orifice plate <NUM> is inclined downward toward a part of the inner wall surface of the liquid-header distributor <NUM> that is opposite the position of connection between the plurality of heat-transfer tubes <NUM> and the liquid-header distributor <NUM>. In this example, the orifice <NUM> is provided in a lower part of the orifice plate <NUM> that is inclined in the top-bottom direction.

The orifice plate <NUM> is inclined relative to a pipe axis D, defined for the liquid-header distributor <NUM>. In the liquid-header distributor <NUM> configured as illustrated in <FIG>, the orifice plate <NUM> extends from a part of the wall surface where the heat-transfer tubes <NUM> are connected and is inclined downward toward another part of the wall surface where the liquid-header inflow/outflow pipe <NUM> is connected.

<FIG> outlines a third example of the liquid-header distributor <NUM> according to Embodiment <NUM>. <FIG> illustrates a section of the liquid-header distributor <NUM> illustrated in <FIG>, taken along line A-A. The orifice <NUM> is a circular hole and is defined by the edge 71a of the orifice plate <NUM> and the inner wall 70b1 of the body 70a.

<FIG> outlines another third example of the liquid-header distributor <NUM> according to Embodiment <NUM>. <FIG> illustrates a section of the liquid-header distributor <NUM> illustrated in <FIG>, taken along line A-A. The orifice <NUM> is an oblong hole and is defined by the edge 71a of the orifice plate <NUM> and the inner wall 70b1 of the body 70a.

In each of the third examples of the liquid-header distributor <NUM> illustrated in <FIG>, the orifice <NUM> is in contact with the inner wall 70b of the body 70a forming the liquid-header distributor <NUM>. Furthermore, a part of the orifice <NUM> is defined by the inner wall 70b1, which forms a part of the surface of the liquid-header distributor <NUM> that is opposite a part where the plurality of heat-transfer tubes <NUM> are connected. Furthermore, the orifice plate <NUM> that defines a part of the orifice <NUM> is inclined downward toward the orifice <NUM>.

The orifice plate <NUM> is inclined in such a direction that the center of gravity of the orifice <NUM> in the section is at a lower position of the orifice plate <NUM>. Furthermore, the top face 71d of the orifice plate <NUM> is recessed in an oblique circular conical shape at the deepest part of which the orifice <NUM> is provided. In short, the liquid-header distributor <NUM> includes the orifice plate <NUM> having a surface inclined toward the orifice <NUM>. Therefore, the liquid refrigerant having reached an area above the orifice plate <NUM> flows along the top face 71d of the orifice plate <NUM> having the orifice <NUM> and gathers around the orifice <NUM>.

Furthermore, the orifice plate <NUM> is inclined downward toward a part of the inner wall surface of the liquid-header distributor <NUM> that is opposite the position of connection between the plurality of heat-transfer tubes <NUM> and the liquid-header distributor <NUM>. Therefore, the liquid refrigerant having reached an area above the orifice plate <NUM> flows along the top face 71d of the orifice plate <NUM> having the orifice <NUM> and gathers around the orifice <NUM>.

The liquid refrigerant gathered around the orifice <NUM> is dragged by the flow of the refrigerant that occurs from the lower side toward the upper side of the orifice <NUM>, and therefore easily flows toward an upper part of the liquid-header distributor <NUM>. Consequently, the liquid refrigerant more easily flows into the plurality of heat-transfer tubes <NUM> connected to the liquid-header distributor <NUM>, and the gathering of the liquid refrigerant in a lower part of the liquid-header distributor <NUM> is suppressed. Accordingly, the performance of the outdoor heat exchanger <NUM> as the heat exchanger is improved.

<FIG> outlines a first example of a liquid-header distributor <NUM> according to Embodiment <NUM>. <FIG> illustrates a section of the liquid-header distributor <NUM> illustrated in <FIG>, taken along line A-A perpendicular to a direction in which a body 70a thereof extends. Elements having the same functions and effects as those such as the liquid-header distributor <NUM> and other elements according to any of Embodiments <NUM> to <NUM> are denoted by corresponding ones of the reference signs, and description of such elements is omitted. The liquid-header distributor <NUM> according to Embodiment <NUM> will be described for further specifying the shape of the orifice plate <NUM> at the orifice <NUM>.

As illustrated in <FIG>, the orifice plate <NUM> of the liquid-header distributor <NUM> according to Embodiment <NUM> includes a projecting wall <NUM> at the inner edge of the orifice <NUM>. The projecting wall <NUM> is formed along the edge of the orifice <NUM>. Therefore, when seen in the direction of the pipe axis D of the liquid-header distributor <NUM>, the projecting wall <NUM> has the same shape as the orifice <NUM>. The projecting wall <NUM> projects upward from the top face 71d of the orifice plate <NUM>. In other words, the projecting wall <NUM> projects from the top face 71d of the orifice plate <NUM> into the top space 78a.

<FIG> outlines a second example of the liquid-header distributor <NUM> according to Embodiment <NUM>. <FIG> illustrates a section of the liquid-header distributor <NUM> illustrated in <FIG>, taken along line A-A perpendicular to the direction in which the body 70a thereof extends. The liquid-header distributor <NUM> according to the second example includes a projecting wall 75a. The projecting wall 75a basically has the same structure as the above projecting wall <NUM> according to the first example.

The projecting wall 75a is, for example, a burr formed by burring. The projecting wall 75a serves as a flange rising at the peripheral edge of the orifice <NUM>. Thus, the projecting wall 75a forms a wall projecting upward from the top face 71d of the orifice plate <NUM>.

As illustrated in <FIG>, the orifice plate <NUM> of each of the liquid-header distributors <NUM> includes the projecting wall <NUM> or the projecting wall 75a provided at the peripheral edge of the orifice <NUM> and projecting upward from the top face 71d. Since the orifice plate <NUM> includes the projecting wall <NUM> or the projecting wall 75a at the periphery of the orifice <NUM>, the liquid refrigerant is less likely to flow downward from the orifice <NUM>.

Therefore, the liquid refrigerant having reached an area above the orifice plate <NUM> is received by a greater amount by the orifice plate <NUM> having the orifice <NUM> than in a case where the orifice plate <NUM> includes neither the projecting wall <NUM> nor the projecting wall 75a. The liquid refrigerant received by the orifice plate <NUM> having the orifice <NUM> is dragged by the refrigerant passing through the orifice <NUM> at an increased speed and therefore easily flows toward an upper part of the liquid-header distributor <NUM>. Furthermore, according to Embodiment <NUM>, the presence of the projecting wall <NUM> or the projecting wall 75a reduces the pressure loss that occurs when the liquid refrigerant passes through the orifice <NUM>. Therefore, the flow rate of the refrigerant that passes through the orifice <NUM> is increased. Hence, in the outdoor heat exchanger <NUM>, an increased amount of liquid refrigerant is caused to flow into those heat-transfer tubes <NUM> that are connected to an upper part of the liquid-header distributor <NUM>. Thus, the performance of the heat exchanger is improved.

<FIG> outlines a first example of a liquid-header distributor <NUM> according to Embodiment <NUM>. <FIG> illustrates a section of the liquid-header distributor <NUM> illustrated in <FIG>, taken along line A-A. <FIG> outlines another first example of the liquid-header distributor <NUM> according to Embodiment <NUM>. <FIG> illustrates a section of the liquid-header distributor <NUM> illustrated in <FIG>, taken along line A-A. Elements having the same functions and effects as those such as the liquid-header distributor <NUM> and other elements according to any of Embodiments <NUM> to <NUM> are denoted by corresponding ones of the reference signs, and description of such elements is omitted. The liquid-header distributor <NUM> according to Embodiment <NUM> will be described for further specifying the shape of the orifice plate <NUM> at the orifice <NUM>.

The orifice plate <NUM> according to the latter first example illustrated in <FIG> is thicker than the orifice plate <NUM> according to the first example illustrated in <FIG>. Each of the orifice plates <NUM> illustrated in <FIG> is shaped such that the thickness of an edge 71c, which defines the orifice <NUM>, is reduced toward the center of the orifice <NUM> of the orifice plate <NUM>.

The edge 71c defining the orifice <NUM> is shaped to be thinner at the top face 71d of the orifice plate <NUM> than at a bottom face 71e. That is, the orifice plate <NUM> is shaped such that the edge 71c defining the orifice <NUM> becomes thinner toward the upper side. The opening size of the orifice <NUM> decreases from the bottom face 71e toward the top face 71d. The edge 71c defining the orifice <NUM> may form a wall surface, defining the hollow part, that extends flat between the bottom face 71e and the top face 71d or curved in an arc shape between the bottom face 71e and the top face 71d.

<FIG> outlines a second example of the liquid-header distributor <NUM> according to Embodiment <NUM>. <FIG> illustrates a section of the liquid-header distributor <NUM> illustrated in <FIG>, taken along line A-A. <FIG> outlines another second example of the liquid-header distributor <NUM> according to Embodiment <NUM>. <FIG> illustrates a section of the liquid-header distributor <NUM> illustrated in <FIG>, taken along line A-A.

The orifice plate <NUM> according to the latter second example illustrated in <FIG> is thicker than the orifice plate <NUM> according to the second example illustrated in <FIG>. Each of the orifice plates <NUM> illustrated in <FIG> is shaped such that the thickness of the edge 71a defining the orifice <NUM> is reduced toward the center of the orifice <NUM> of the orifice plate <NUM>.

The orifice <NUM> is narrowed toward the upper side in the direction of the pipe axis of the liquid-header distributor <NUM>. The edge 71a defining the orifice <NUM> becomes thinner toward the center of the orifice <NUM> and on a side near the top face 71d of the orifice plate <NUM> than on a side near the bottom face 71e of the orifice plate <NUM>. That is, the orifice plate <NUM> is shaped such that the opening size of the orifice <NUM> decreases from the side near the bottom face 71e toward the side near the top face 71d. The edge 71a defining the orifice <NUM> may form a wall surface, defining the hollow part, that extends flat between the bottom face 71e and the top face 71d or curved in an arc shape between the bottom face 71e and the top face 71d.

In the liquid-header distributor <NUM> according to Embodiment <NUM>, the edge 71c and the edge 71a each defining the orifice <NUM> become thinner toward the upper side of the liquid-header distributor <NUM>. That is, in the liquid-header distributor <NUM> according to Embodiment <NUM>, the opening size of the orifice <NUM> decreases toward the upper side of the liquid-header distributor <NUM>.

In the liquid-header distributor <NUM> configured as above, the pressure loss that occurs when the refrigerant passes through the orifice <NUM> is reduced. Therefore, the flow rate of the refrigerant that passes through the orifice <NUM> is increased. Hence, in the outdoor heat exchanger <NUM>, an increased amount of liquid refrigerant is caused to flow into those heat-transfer tubes <NUM> that are connected to an upper part of the liquid-header distributor <NUM>. Thus, the performance of the heat exchanger is improved.

The air-conditioning apparatus <NUM> includes the outdoor heat exchanger <NUM> according to any of Embodiments <NUM> to <NUM> described above. Hence, the air-conditioning apparatus <NUM> produces the effects produced by any of the outdoor heat exchangers <NUM> according to Embodiments <NUM> to <NUM>. Since the air-conditioning apparatus <NUM> includes the outdoor heat exchanger <NUM>, the separation between the gas refrigerant and the liquid refrigerant contained in the two-phase gas-liquid refrigerant is prevented. Therefore, the gas refrigerant and the liquid refrigerant are evenly distributed to those heat-transfer tubes <NUM> that are located in a downstream part of the liquid-header distributor <NUM>.

The liquid-header distributors <NUM> according to Embodiments <NUM> to <NUM> may each be vertically oriented such that the body 70a thereof extends in the vertical direction, or horizontally oriented such that the body 70a thereof extends in the horizontal direction. Furthermore, the body 70a of each of the liquid-header distributors <NUM> according to Embodiments <NUM> to <NUM> may be inclined relative to the vertical direction.

<FIG> outlines a modification of the liquid-header distributor <NUM>. <FIG> illustrates a section of the liquid-header distributor <NUM> illustrated in <FIG>, taken along line A-A. <FIG> outlines another modification of the liquid-header distributor <NUM>. <FIG> illustrates a section of the liquid-header distributor <NUM> illustrated in <FIG>, taken along line A-A. The body 70a is not limited to the one whose section perpendicular to the axial direction of the body 70a is circular and may have a section in a substantially U shape, as illustrated in <FIG>, or any other shape. Furthermore, the number of orifices <NUM> is not limited to one and may be two or more, as illustrated in <FIG>.

The outdoor heat exchanger <NUM> according to any of the above embodiments of the present invention is applicable not only to the above air-conditioning apparatus <NUM> but also to, for example, a heat-pump apparatus, a water heater, or a refrigerator.

Claim 1:
A heat exchanger (<NUM>) comprising:
- a distributor (<NUM>) extending in a top-bottom direction in a form of a pipe and in which refrigerant flows;
- a plurality of heat-transfer tubes (<NUM>) connected to the distributor (<NUM>) while being arranged at intervals from one another in the top-bottom direction, the heat-transfer tubes (<NUM>) receiving the refrigerant flowing from the distributor (<NUM>); and
- a refrigerant inflow pipe (<NUM>) connected to the distributor (<NUM>) at a position below a lowest one of the plurality of heat-transfer tubes (<NUM>) and through which the refrigerant flows into the distributor (<NUM>),
- wherein the plurality of heat-transfer tubes (<NUM>) connected to the distributor (<NUM>) stick out into an internal space (<NUM>) of the distributor (<NUM>) such that when the plurality of heat-transfer tubes (<NUM>) and a part defined as the internal space (<NUM>) are projected on a plane perpendicular to an axial direction of the distributor (<NUM>), the plurality of heat-transfer tubes (<NUM>) occupies one-half or greater of the part defined as the internal space (<NUM>);
- wherein the distributor (<NUM>) includes an orifice plate (<NUM>) being in a form of a plate and dividing the internal space (<NUM>) into an upper space and a lower space in a longitudinal direction of the distributor (<NUM>);
- wherein the orifice plate (<NUM>) is located above the lowest one of the plurality of heat-transfer tubes (<NUM>) in the internal space (<NUM>); and
wherein the orifice plate (<NUM>) has an orifice (<NUM>) that is a through-hole through which the upper space and the lower space communicate with each other.