Heat exchanger unit, air conditioning indoor unit, and refrigeration cycle system

Abstract

To improve the performance of a heat exchanger equipped with a flattened tube having multiple internal flow channels. [Solution] A connecting channel (75) is formed in the plate structure (62) of the heat exchanger unit (40). The connecting channel (75) has a first part (80), a second part (85), and a third part (90). All internal channels (50a) of the first heat transfer tube (51) are connected to the first part (80). All internal channels (50a) of the second heat transfer tube (52) are connected to the second part (85). One end of the third part (90) is connected to one of the first long sides (81a) of the first part (80). The other end of the third part (90) is connected to one of the second long sides (86b) of the second part (85).

Description

Technical Field

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[0001] The present disclosure relates to a heat exchanger unit, an air conditioner indoor unit, and a refrigeration cycle apparatus.

Background Art

[0002] Patent Document 1 discloses a heat exchanger including a plurality of heat transfer tubes. The heat transfer tubes of this heat exchanger are flat tubes having an oval cross-sectional shape. Two tube rows are formed in this heat exchanger. In this heat exchanger, the two tube rows are arranged side by side in the front and rear. Each tube row is composed of a plurality of heat transfer tubes. In each tube row, the plurality of heat transfer tubes are arranged in a line at a constant interval in the vertical direction.

[0003] Headers are connected to the ends of the heat transfer tubes in each tube row. The header is composed of a plurality of laminated plate-like members. Inside the header, a connection flow path is formed that connects the first heat transfer tube constituting the front tube row and the second heat transfer tube constituting the rear tube row. The connection flow path is formed so as to connect the short side of the end face of the first heat transfer tube and the short side of the end face of the second heat transfer tube. The refrigerant flowing through the heat exchanger flows from one of the first heat transfer tube and the second heat transfer tube to the other through the connection flow path in the header.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the flat tube used as a heat transfer tube, a plurality of internal flow paths may be formed. Each internal flow path is formed from one end to the other end of the flat tube. The plurality of internal flow paths are arranged in the width direction of the flat tube (the longitudinal direction of the cross section of the flat tube).

[0006] As described above, in the heat exchanger of Patent Document 1, the connecting channel in the header connects the short side of the end face of the first heat transfer tube that constitutes the front row of tubes to the short side of the end face of the second heat transfer tube that constitutes the rear row of tubes. Therefore, if a flat tube with multiple internal channels is used as the heat transfer tube of the heat exchanger of Patent Document 1, the flow rate of refrigerant flowing into each internal channel of the flat tube may be higher in the internal channels closer to the connecting channel and lower in the internal channels further away from the connecting channel. If the flow rate of refrigerant in each internal channel of the flat tube becomes uneven, the performance of the heat exchanger will not be fully realized.

[0007] The purpose of this disclosure is to improve the performance of a heat exchanger equipped with a flattened tube having multiple internal flow channels. [Means for solving the problem]

[0008] A first aspect of this disclosure is a heat exchanger unit (40) comprising a plurality of fins (53) and heat transfer tubes (50), wherein the heat transfer medium flowing through the heat transfer tubes (50) exchanges heat with air.

[0009] In the first embodiment, each of the plurality of heat transfer tubes (50) is a flattened tube with a plurality of internal flow channels (50a) formed inside it, and in each of the plurality of heat transfer tubes (50), the plurality of internal flow channels (50a) are arranged in a row in the width direction of the heat transfer tube (50), and the plurality of heat transfer tubes (50) include a plurality of first heat transfer tubes (51) and a plurality of second heat transfer tubes (52), with the plurality of first heat transfer tubes (51) arranged in a row with space between them forming a first tube row (56), and the plurality of second heat transfer tubes (52) arranged in a row with space between them forming a second tube row (57), and the first tube row (56) and the second tube row (57) are arranged in order from upstream to downstream of the airflow passing through the heat exchanger unit (40).

[0010] In a first embodiment, the heat exchanger unit (40) includes a plate structure (62) joined to the ends of a plurality of heat transfer tubes (50), with a connecting channel (75) formed inside that connects one first heat transfer tube (51) to one second heat transfer tube (52). The connecting channel (75) has a first portion (80) facing the end face of the first heat transfer tube (51) and through which all of the internal channels (50a) formed in the first heat transfer tube (51) communicate; a second portion (85) facing the end face of the second heat transfer tube (52) and through which all of the internal channels (50a) formed in the second heat transfer tube (52) communicate; and a third portion (90) communicating with both the first portion (80) and the second portion (85).

[0011] In the first embodiment, the first portion (80) has a pair of first long sides (81a, 81b) along the width direction of the first heat transfer tube (51), the second portion (85) has a pair of second long sides (86a, 86b) along the width direction of the second heat transfer tube (52), one end of the third portion (90) is connected to only one of the pair of first long sides (81a, 81b) of the first portion (80), and the other end of the third portion (90) is connected to only one of the pair of second long sides (86a, 86b) of the second portion (85).

[0012] In the heat exchanger unit (40) of the first embodiment, when the heat transfer medium flows through the connecting channel (75) from the first heat transfer tube (51) to the second heat transfer tube (52), the heat transfer medium flowing through the third section (90) flows into the second section (85) from the second long side (86a, 86b) along the width direction of the second heat transfer tube (52) and is distributed to all of the multiple internal tube channels (50a) aligned in the width direction of the second heat transfer tube (52). Also, when the heat transfer medium flows through the connecting channel (75) from the second heat transfer tube (52) to the first heat transfer tube (51), the heat transfer medium flowing through the third section (90) flows into the first section (80) from the first long side (81a, 81b) along the width direction of the first heat transfer tube (51) and is distributed to all of the multiple internal tube channels (50a) aligned in the width direction of the first heat transfer tube (51).

[0013] Therefore, in the first embodiment, the heat transfer medium flowing through the connecting channel (75) is distributed to all the internal channels (50a) formed in the heat transfer tube (50), and the difference in the flow rate of the heat transfer medium flowing through each internal channel (50a) of a single heat transfer tube (50) is kept small. As a result, the performance of the heat exchanger unit (40) is improved.

[0014] A second aspect of the present disclosure is that, in the first aspect, the plate structure (62) has a plurality of overlapping and joined plate members (65), and the first portion (80), second portion (85), and third portion (90) of the connecting channel (75) are formed in one plate member (65).

[0015] In the second embodiment, a first portion (80), a second portion (85), and a third portion (90) of the connecting channel (75) are formed on a single plate member (65).

[0016] A third aspect of the present disclosure is the plate structure (62) having a plurality of overlapping and joined plate members (65) the plurality of plate members (65) including a first plate member (71) and a second plate member (72) located on the opposite side of the heat transfer tube (50) from the first plate member (71), the first portion (80) and the second portion (85) of the connecting channel (75) being formed across both the first plate member (71) and the second plate member (72), and the third portion (90) of the connecting channel (75) being formed only on the second plate member (72) of the first plate member (71) and the second plate member (72).

[0017] In a third embodiment, the first portion (80) and the second portion (85) of the connecting channel (75) are formed across both the first plate member (71) and the second plate member (72). On the other hand, the third portion (90) of the connecting channel (75) is formed on the second plate member (72).

[0018] A fourth aspect of the present disclosure is, in any one of the first to third aspects, the width of the first portion (80) is greater than or equal to the width of the first heat transfer tube (51), the width of the second portion (85) is greater than or equal to the width of the second heat transfer tube (52), and the width of the third portion (90) is less than or equal to the width of the first heat transfer tube (51) and less than or equal to the width of the second heat transfer tube (52).

[0019] In the connecting channel (75) of the fourth embodiment, the width of the third portion (90) is less than or equal to the width of the first portion (80) and less than or equal to the width of the second portion (85).

[0020] A fifth aspect of the present disclosure is that, in any one of the first to fourth aspects, the first long side (81a, 81b) of the first part (80) to which one end of the third part (90) is connected is located on the same side as the second long side (86a, 86b) of the second part (85) to which the other end of the third part (90) is connected.

[0021] In the fifth aspect, the first long side (81b) of the first part (80) to which one end of the third part (90) is connected, and the second long side (86b) of the second part (85) to which the other end of the third part (90) is connected, are located on the same side. For example, if one end of the third part (90) is connected to the lower first long side (81b) of the first part (80), the other end of the third part (90) is connected to the lower second long side (86b) of the second part (85).

[0022] A sixth aspect of the present disclosure is the fifth aspect, wherein the third portion (90) has a straight portion (94) formed opposite the first long side (81a, 81b) and the second long side (86a, 86b).

[0023] In the connecting channel (75) of the sixth embodiment, the third portion (90) has a straight portion (94). The straight portion (94) is formed at a position opposite the first long side (81a, 81b) of the first portion (80) and the second long side (86a, 86b) of the second portion (85).

[0024] In the seventh aspect of the present disclosure, in any one of the first to fourth aspects, the first long sides (81a, 81b) of the first part (80) to which one end of the third part (90) is connected are located on the opposite side of the second long sides (86a, 86b) of the second part (85) to which the other end of the third part (90) is connected.

[0025] In the seventh aspect, the first long sides (81a, 81b) of the first part (80) to which one end of the third part (90) is connected and the second long sides (86a, 86b) of the second part (85) to which the other end of the third part (90) is connected are located on the opposite sides. For example, when one end of the third part (90) is connected to the upper first long side (81a) of the first part (80), the other end of the third part (90) is connected to the lower second long side (86b) of the second part (85).

[0026] In the eighth aspect of the present disclosure, in the seventh aspect, the center line (L1) in the width direction of the connection flow path (75) is located above a straight line (L2) connecting the midpoint (CP1) of the first long side (81a, 81b) to which one end of the third part (90) is connected and the midpoint (CP2) of the second long side (86a, 86b) to which the other end of the third part (90) is connected.

[0027] In the eighth aspect, the center line (L1) of the connection flow path (75) is located above the straight line (L2) connecting the midpoint (CP1) of the first long side (81a, 81b) and the midpoint (CP2) of the second long side (86a, 86b).

[0028] In the ninth aspect of the present disclosure, in any one of the first to fourth aspects, one end of the third part (90) is connected to a portion of the first long side (81a, 81b) that includes the midpoint (CP1) of the first long side (81a, 81b), and the other end of the third part (90) is connected to a portion of the second long side (86a, 86b) that includes the midpoint (CP2) of the second long side (86a, 86b).

[0029] In the ninth embodiment, one end of the third part (90) is connected to the portion of the first long side (81a, 81b) of the first part (80) that includes the midpoint (CP1). The other end of the third part (90) is connected to the portion of the second long side (86a, 86b) of the second part (85) that includes the midpoint (CP2).

[0030] A tenth aspect of this disclosure is an air conditioning indoor unit (30) comprising a heat exchanger unit (40) according to any one of the first to ninth aspects described above, wherein the heat exchanger unit (40) exchanges heat with indoor air using the heat transfer medium.

[0031] In the tenth embodiment, one of the first to ninth heat exchanger units (40) is provided in the air conditioning indoor unit (30).

[0032] An eleventh aspect of the present disclosure is a refrigeration cycle device (10) comprising a refrigerant circuit (11) having one of the first to ninth heat exchanger units (40), wherein a refrigerant is circulated in the refrigerant circuit (11) to perform a refrigeration cycle.

[0033] In the eleventh embodiment, one of the first to ninth heat exchanger units (40) is provided in the refrigerant circuit (11) of the refrigeration cycle device (10). [Brief explanation of the drawing]

[0034] [Figure 1] Figure 1 is a piping diagram showing the refrigerant circuit of the air conditioning system of Embodiment 1. [Figure 2] Figure 2 is a schematic front view of the indoor unit of Embodiment 1. [Figure 3] Figure 3 is a schematic cross-sectional view of the indoor unit of Embodiment 1. [Figure 4] Figure 4 is a schematic front view of the heat exchanger unit installed in the indoor unit of Embodiment 1. [Figure 5] Figure 5 is a cross-sectional view of the main parts of the second plate stack and heat transfer tubes in the heat exchanger unit of Embodiment 1. [Figure 6]Figure 6 is a cross-sectional view of the main part of the second plate stack in the heat exchanger unit of Embodiment 1. [Figure 7] Figure 7 is a cross-sectional view of the main part of the second plate stack in the heat exchanger unit of the modified example 1 of Embodiment 1. [Figure 8] Figure 8 is a cross-sectional view of the main part of the second plate stack in a heat exchanger unit of a modified example 2 of Embodiment 1. [Figure 9] Figure 9 is a cross-sectional view of the main part of the second plate stack in the heat exchanger unit of the modified example 3 of Embodiment 1. [Figure 10] Figure 10 is a cross-sectional view of the main parts of the second plate stack and heat transfer tubes in the heat exchanger unit of Embodiment 2. [Figure 11] Figure 11 is a cross-sectional view of the main part of the second plate stack in the heat exchanger unit of Embodiment 2. [Figure 12] Figure 12 is a cross-sectional view of the main part of the second plate stack in the heat exchanger unit of the modified example 1 of Embodiment 2. [Figure 13] Figure 13 is a cross-sectional view of the main part of the second plate stack in the heat exchanger unit of the modified example 2 of Embodiment 2. [Figure 14] Figure 14 is a schematic cross-sectional view of the indoor unit of Embodiment 3. [Figure 15] Figure 15 is a cross-sectional view of the main part of the second plate stack in the heat exchanger unit of Embodiment 3. [Figure 16] Figure 16 is a cross-sectional view of the main parts of the second plate stack and heat transfer tubes in a heat exchanger unit of a first modified example of another embodiment. [Modes for carrying out the invention]

[0035] Embodiment 1 Embodiment 1 will now be described.

[0036] -Overall configuration of the air conditioning system- This embodiment is an air conditioning system (10) equipped with a heat exchanger unit (40). The air conditioning system (10) adjusts the temperature of the air in the target space, which is an indoor space (200).

[0037] As shown in Figure 1, the air conditioning system (10) is an example of a refrigeration cycle system equipped with a refrigerant circuit (11). The refrigerant circuit (11) is filled with a refrigerant, which is a heat transfer medium. The refrigerant circuit (11) performs a refrigeration cycle by circulating the refrigerant.

[0038] The air conditioning system (10) comprises an outdoor unit (20), an indoor unit (30), a first connecting pipe (12), and a second connecting pipe (13). The air conditioning system (10) is a paired system having one outdoor unit (20) and one indoor unit (30). The first connecting pipe (12) is a gas connecting pipe, and the second connecting pipe (13) is a liquid connecting pipe. In the air conditioning system (10), a refrigerant circuit (11) is formed by connecting the outdoor unit (20) and the indoor unit (30) with the first connecting pipe (12) and the second connecting pipe (13).

[0039] The outdoor unit (20) is installed outdoors. The outdoor unit (20) includes an outdoor casing (20a) and a compressor (21), an outdoor heat exchanger (22), an outdoor expansion valve (23), a four-way switching valve (24), and an outdoor fan (25) housed in the outdoor casing (20a).

[0040] The compressor (21) is a rotary compressor such as an oscillating piston type, rotary type, or scroll type. The outdoor heat exchanger (22) is a fin-and-tube type air heat exchanger. The outdoor heat exchanger (22) exchanges heat between the refrigerant and the outdoor air. The outdoor expansion valve (23) is an electronically controlled expansion valve with a variable opening. The four-way switching valve (24) switches between a first state (shown by the solid line in Figure 1) and a second state (shown by the dashed line in Figure 1). In the first state, the four-way switching valve (24) connects the discharge end of the compressor (21) to the gas end of the outdoor heat exchanger (22), and also connects the suction end of the compressor (21) to the first connecting pipe (12). The four-way switching valve (24) in the second state connects the discharge section of the compressor (21) to the first connecting pipe (12), and also connects the suction section of the compressor (21) to the gas end of the outdoor heat exchanger (22). The outdoor fan (25) is a propeller fan.

[0041] The indoor unit (30) comprises a casing (31), a heat exchanger unit (40) and an indoor fan (32) housed within the casing (31).

[0042] -Operation of the air conditioning system- The air conditioning system (10) selectively performs cooling operation and heating operation.

[0043] During cooling operation, the four-way switching valve (24) is set to the state shown by the solid line in Figure 1. When the compressor (21) operates, the refrigerant circulates in the refrigerant circuit (11), and the refrigeration cycle is performed. In the refrigerant circuit (11), the outdoor heat exchanger (22) functions as a condenser, and the indoor heat exchanger (41) functions as an evaporator. The indoor unit (30) blows the air cooled in the indoor heat exchanger (41) into the indoor space (200).

[0044] During heating operation, the four-way switching valve (24) is set to the state shown by the dashed line in Figure 1. When the compressor (21) operates, the refrigerant circulates in the refrigerant circuit (11), and the refrigeration cycle is performed. In the refrigerant circuit (11), the indoor heat exchanger (41) functions as a condenser, and the outdoor heat exchanger (22) functions as an evaporator. The indoor unit (30) blows the air heated in the indoor heat exchanger (41) into the indoor space (200).

[0045] -Indoor unit- Details of the indoor unit (30), which is an indoor air conditioner, will be explained with reference to Figures 2 and 3. The indoor unit (30) in this embodiment is a wall-mounted type installed on the wall of the indoor space (200). The terms "up," "down," "right," "left," "front," and "back" described below correspond to the directions of the arrows shown in Figures 2 and 3, and indicate the direction when the indoor unit (30) is viewed from the front.

[0046] <Casing> The casing (31) is formed in a horizontally elongated box shape from left to right.

[0047] An intake port (33) is formed at the top of the casing (31). The intake port (33) extends in the longitudinal direction (left-right direction) of the casing (31). An outlet port (34) is formed at the bottom of the casing (31). The outlet port (34) extends in the longitudinal direction of the casing (31).

[0048] <Heat exchanger unit> The heat exchanger unit (40) comprises one indoor heat exchanger (41) and one indoor expansion valve (42). The indoor heat exchanger (41) comprises one heat exchanger body (45) and two plate stacks (61, 62).

[0049] <Indoor fan> The indoor fan (32) is a cross-flow fan. The indoor fan (32) is located below the heat exchanger unit (40). The fan rotor of the indoor fan (32) extends along the longitudinal direction of the casing (31).

[0050] <flap> The indoor unit (30) has a flap (36) that adjusts the direction of the air blown out from the air outlet (34). The flap (36) adjusts the airflow direction in the vertical direction. The indoor unit (30) may have multiple flaps (36). The flaps (36) may also adjust the airflow direction in the horizontal direction.

[0051] -Heat exchanger unit- As described above, the heat exchanger unit (40) comprises an indoor heat exchanger (41) and an indoor expansion valve (42).

[0052] <Indoor heat exchanger> As described above, the indoor heat exchanger (41) comprises one heat exchanger body (45) and two plate stacks (61, 62). The indoor heat exchanger (41) is a fin-and-tube type air heat exchanger. The indoor heat exchanger (41) exchanges heat between the refrigerant and the indoor air. Each plate stack (61, 62) is a plate structure. Note that the number of plate stacks (61, 62) in the indoor heat exchanger (41) is merely an example.

[0053] <Heat exchanger body> As shown in Figure 3, the heat exchanger body (45) comprises a first heat exchange section (46), a second heat exchange section (47), and a third heat exchange section (48). The first heat exchange section (46) and the second heat exchange section (47) constitute the front heat exchange section (45A). The third heat exchange section (48) constitutes the rear heat exchange section (45B). Note that the number of heat exchange sections in the heat exchanger body (45) is merely an example. The heat exchanger body (45) may have one or more heat exchange sections.

[0054] The front heat exchange section (45A) is located towards the front of the casing (31). The rear heat exchange section (45B) is located towards the rear of the casing (31). The heat exchanger body (45) is provided to surround the front, top, and rear of the indoor fan (32).

[0055] <Indoor expansion valve> The indoor expansion valve (42) is an electronically controlled expansion valve with a variable opening. As shown in Figure 1, one end of the indoor expansion valve (42) is connected to the front heat exchanger (45A) via piping. The other end of the indoor expansion valve (42) is connected to the rear heat exchanger (45B) via piping.

[0056] <First heat exchange section, second heat exchange section, third heat exchange section> As shown in Figure 3, each of the first heat exchange section (46), the second heat exchange section (47), and the third heat exchange section (48) is equipped with multiple fins (53) and heat transfer tubes (50). The fins (53) and heat transfer tubes (50) are made of an aluminum alloy. However, the fins (53) and heat transfer tubes (50) may be made of a metal other than an aluminum alloy.

[0057] The fins (53) are generally rectangular, thin plate-like members. In each heat exchange section (46, 47, 48), multiple fins (53) are arranged in a line in the left-right direction in Figure 4, facing each other and spaced at a constant distance from one another.

[0058] As shown in Figure 3, the heat transfer tube (50) is a flattened tube with an oval cross-section. The heat transfer tube (50) is a straight tube. The outer surface of the heat transfer tube (50) includes a pair of flat surfaces. In each heat exchange section (46, 47, 48), the multiple heat transfer tubes (50) are arranged in the direction of the long side of the fin (53) at a constant distance from each other, with their respective flat surfaces facing each other.

[0059] Each heat exchange section (46, 47, 48) has a first tube row (56) and a second tube row (57). Each of the first tube row (56) and the second tube row (57) is composed of multiple heat transfer tubes (50). In each of the first tube row (56) and the second tube row (57), the multiple heat transfer tubes (50) are arranged in a line along the long side of the fin (53) at regular intervals from one another.

[0060] The heat transfer tubes (50) constituting the first tube row (56) are first heat transfer tubes (51). In the first tube row (56), multiple first heat transfer tubes (51) are arranged in a line at a constant pitch. The heat transfer tubes (50) constituting the second tube row (57) are second heat transfer tubes (52). In the second tube row (57), multiple second heat transfer tubes (52) are arranged in a line at a constant pitch. The pitch of the multiple first heat transfer tubes (51) in the first tube row (56) and the pitch of the multiple second heat transfer tubes (52) in the second tube row (57) are equal to each other.

[0061] In each heat exchange section (46, 47, 48), the first tube row (56) follows the long side of the windward side of the fin (53), and the second tube row (57) follows the long side of the leeward side of the fin (53). Also, in each heat exchange section (46, 47, 48), the first heat transfer tube (51) of the first tube row (56) and the second heat transfer tube (52) of the second tube row (57) are aligned in the direction of the short side of the fin (53). Therefore, the positions of each first heat transfer tube (51) and the second heat transfer tube (52) closest to each first heat transfer tube (51) coincide in the direction of the long side of the fin (53).

[0062] The first heat exchange section (46) is positioned such that the longer windward side of the fin (53) faces forward and diagonally upward. The second heat exchange section (47) is positioned such that the longer windward side of the fin (53) faces forward and diagonally downward. The second heat exchange section (47) is positioned below the first heat exchange section (46). The third heat exchange section (48) is positioned such that the longer windward side of the fin (53) faces backward and diagonally upward.

[0063] <Heat transfer tube> As shown in Figures 5 and 6, the heat transfer tube (50) is a flattened tube with an oval cross-section. The heat transfer tube (50) is also a straight tube. The total length of the heat transfer tube (50) is the distance from one end face to the other. The width Wt of the heat transfer tube (50) is the length of the cross-section of the heat transfer tube (50) in the longitudinal direction. The thickness THt of the heat transfer tube (50) is the length of the cross-section of the heat transfer tube (50) in the transverse direction. The multiple heat transfer tubes (50) provided in each heat exchange section (46, 47, 48) have substantially equal widths Wt and substantially equal thicknesses THt.

[0064] Multiple internal flow channels (50a) are formed in the heat transfer tube (50). In the example shown in Figures 5 and 6, five internal flow channels (50a) are formed in the heat transfer tube (50). Each internal flow channel (50a) is a straight channel formed from one end to the other of the heat transfer tube (50). Each internal flow channel (50a) opens to both the end face and the other end face of the heat transfer tube (50). In the heat transfer tube (50), the multiple internal flow channels (50a) are arranged parallel to each other. Also, in the heat transfer tube (50), the multiple internal flow channels (50a) are arranged in a line in the width direction of the heat transfer tube (50).

[0065] <First plate laminate, second plate laminate> The first plate stack (61) and the second plate stack (62) are each thick plate-shaped members formed by stacking multiple plate members. Inside each plate stack (61, 62), a coolant flow path is formed to connect two or more heat transfer tubes (50).

[0066] In each plate stack (61, 62), the multiple plate members (65) that constitute each are joined to each other by brazing. The multiple plate members (65) that constitute each plate stack (61, 62) are each made of an aluminum alloy. However, the material of the plate members (65) may be a metal other than an aluminum alloy.

[0067] The first plate stack (61) is positioned to the right of the heat exchanger body (45) in Figure 4. The first plate stack (61) is joined to one end of the heat transfer tubes (50) of each heat exchange section (46, 47, 48).

[0068] The second plate stack (62) is positioned to the left of the heat exchanger body (45) in Figure 4. The second plate stack (62) is joined to the other end of the heat transfer tube (50) of each heat exchange section (46, 47, 48).

[0069] -Second Plate Laminate- The second plate stack (62) will be explained with reference to Figure 5. Figure 5 shows a cross-section of the portion of the second plate stack (62) that connects to the heat transfer tubes (50) of the first heat exchange section (46). In Figure 5, the 5A-5A and 5B-5B sections are cross-sections along the cutting lines indicated in the 5C-5C section. Similarly, the 5C-5C section is a cross-section along the cutting lines indicated in the 5A-5A and 5B-5B sections.

[0070] The second plate laminate (62) of this embodiment comprises three plate members (65). The second plate laminate (62) may comprise four or more plate members (65).

[0071] Specifically, the second plate laminate (62) comprises a base plate (70), a first plate (71), and a second plate (72). Each of the base plate (70), the first plate (71), and the second plate (72) is a plate member (65). Each of the base plate (70), the first plate (71), and the second plate (72) is formed in a flat plate shape.

[0072] In the second plate laminate (62), the base plate (70), the first plate (71), and the second plate (72) are arranged in order from the side closest to the heat transfer tubes (50). The second plate (72) is positioned on the side opposite to the heat transfer tubes (50) relative to the first plate (71). The base plate (70) is joined to the first plate (71), and the first plate (71) is joined to the second plate (72) by brazing.

[0073] The ends of the first heat transfer tubes (51) that make up the first tube row (56) and the ends of the second heat transfer tubes (52) that make up the second tube row (57) are inserted through the base plate (70). The first heat transfer tubes (51) and the second heat transfer tubes (52) are joined to the base plate (70) by brazing.

[0074] A connecting channel (75) is formed in the first plate (71). The connecting channel (75) is made up of holes that penetrate the first plate (71). The connecting channel (75) is a refrigerant channel for connecting one first heat transfer tube (51) and one second heat transfer tube (52).

[0075] The connecting channel (75) shown in Figure 5 connects one first heat transfer tube (51) to one second heat transfer tube (52) located next to the first heat transfer tube (51) directly above it. The connecting channel (75) communicates with all the internal channels (50a) formed in the first heat transfer tube (51) and with all the internal channels (50a) formed in the second heat transfer tube (52).

[0076] The second plate (72) covers the connecting channel (75) of the first plate (71) and seals the connecting channel (75).

[0077] -Connection channel of the second plate stack- The connecting channel (75) formed in the second plate stack (62) will be explained with reference to Figure 6. Figure 6 is an enlarged view of the "5C-5C cross-section" shown in Figure 5.

[0078] The connecting channel (75) is divided into a first part (80), a second part (85), and a third part (90).

[0079] <Part 1> The first portion (80) is the portion that overlaps with the end face of the first heat transfer tube (51) when viewed from the front side of the end face of the first heat transfer tube (51). The first portion (80) overlaps the entire end face of the first heat transfer tube (51). The shape of the first portion (80), when viewed from the stacking direction of the plate member (65) in the second plate stack (62) (in other words, the shape that appears in Figure 6), substantially matches the shape of the end face of the first heat transfer tube (51). The width Wp1 of the first portion (80) is substantially equal to the width Wt of the first heat transfer tube (51).

[0080] The first part (80) covers the end face of the first heat transfer tube (51). The end face of the first heat transfer tube (51) faces the first part (80). All (five in the example shown in Figure 6) internal flow channels (50a) formed in the first heat transfer tube (51) are in communication with the first part (80).

[0081] The first part (80) has a pair of first long sides (81a, 81b) and a pair of first semicircular parts (82a, 82b). Each first long side (81a, 81b) is a straight portion along the width direction of the first heat transfer tube (51). Each first long side (81a, 81b) is substantially parallel to each other. Each first semicircular part (82a, 82b) is a semicircularly curved portion. One first semicircular part (82a) is connected to one end of each first long side (81a, 81b). The other first semicircular part (82b) is connected to the other end of each first long side (81a, 81b).

[0082] <Second part> The second portion (85) is the portion that overlaps with the end face of the second heat transfer tube (52) when viewed from the front side of the end face of the second heat transfer tube (52). The second portion (85) overlaps the entire end face of the second heat transfer tube (52). The shape of the second portion (85), when viewed from the stacking direction of the plate members (65) in the second plate stack (62) (in other words, the shape that appears in Figure 6), substantially matches the shape of the end face of the second heat transfer tube (52). The width Wp2 of the second portion (85) is substantially equal to the width Wt of the second heat transfer tube (52).

[0083] The second part (85) covers the end face of the second heat transfer tube (52). The end face of the second heat transfer tube (52) faces the second part (85). All (five in the example shown in Figure 6) internal tube flows (50a) formed in the second heat transfer tube (52) are in communication with the second part (85).

[0084] The second section (85) has a pair of second long sides (86a, 86b) and a pair of second semicircular sections (87a, 87b). Each second long side (86a, 86b) is a straight section along the width direction of the second heat transfer tube (52). Each second long side (86a, 86b) is substantially parallel to each other. Each second semicircular section (87a, 87b) is a curved section in the shape of a semicircle. One second semicircular section (87a) is connected to one end of each second long side (86a, 86b). The other second semicircular section (87b) is connected to the other end of each second long side (86a, 86b).

[0085] <3rd part> The third section (90) is the section that connects the first section (80) and the second section (85). The third section (90) is connected to both the first section (80) and the second section (85).

[0086] The third part (90) extends diagonally in a straight line from the first part (80) toward the second part (85). One side (90a) of the third part (90) is a straight section connecting one of the first semicircular parts (82a) of the first part (80) and one of the second semicircular parts (87a) of the second part (85). The other side (90b) of the third part (90) is a straight section connecting the other first semicircular part (82b) of the first part (80) and the other second semicircular part (87b) of the second part (85).

[0087] One end of the third part (90) connects to the upper first long side (81a) and the other first semicircular part (82b) of the first part (80). Therefore, one end of the third part (90) connects to only one of the pair of first long sides (81a, 81b) of the first part (80). Also, one end of the third part (90) connects to the entire first long side (81a). Therefore, one end of the third part (90) connects to the portion of the first long side (81a) that includes the midpoint (CP1) of the first long side (81a).

[0088] The other end of the third part (90) connects to the lower second long side (86b) and one of the second semicircular parts (87a) of the second part (85). Therefore, the other end of the third part (90) connects to only one of the pair of second long sides (86a, 86b) of the second part (85). Also, the other end of the third part (90) connects to the entire second long side (86b). Therefore, the other end of the third part (90) connects to the portion of the second long side (86b) that includes the midpoint (CP2) of the second long side (86b).

[0089] One end of the third part (90) is connected to the upper first long side (81a) of the first part (80), and the other end of the third part (90) is connected to the lower second long side (86b) of the second part (85). Therefore, the first long side (81a) of the first part (80) to which one end of the third part (90) is connected is located on the opposite side from the second long side (86b) of the second part (85) to which the other end of the third part (90) is connected. The second long side (86b) of the second part (85) to which the other end of the third part (90) is connected is the second long side of the pair of second long sides (86a, 86b) of the second part (85) that is closer to the first long side (81a) of the first part (80) to which one end of the third part (90) is connected.

[0090] -Refrigerant flow in the connecting channel- In the connecting channel (75) of the second plate stack (62), the refrigerant flows from one of the first heat transfer tubes (51) and the second heat transfer tube (52) to the other. The direction of refrigerant flow in the indoor heat exchanger (41) reverses between cooling and heating operation. For example, if the refrigerant flows through the connecting channel (75) from the second heat transfer tube (52) to the first heat transfer tube (51) during cooling operation, then during heating operation, the refrigerant flows through the connecting channel (75) from the first heat transfer tube (51) to the second heat transfer tube (52).

[0091] <First heat transfer tube → Second heat transfer tube> The flow of refrigerant in the connecting channel (75) when the refrigerant flows from the first heat transfer tube (51) to the second heat transfer tube (52) will be explained.

[0092] The refrigerant flowing through each internal channel (50a) of the first heat transfer tube (51) flows into and merges with the first section (80) of the connecting channel (75). The refrigerant that has merged in the first section (80) flows through the third section (90) and into the second section (85). The refrigerant that has entered the second section (85) splits and flows into each internal channel (50a) of the second heat transfer tube (52).

[0093] As described above, the other end of the third section (90) is connected to the entire second long side (86b) of the second section (85). In addition, all the internal flow channels (50a) arranged in a line in the width direction of the second heat transfer tube (52) open to the end face of the second heat transfer tube (52) facing the second section (85). Therefore, the refrigerant flowing from the third section (90) into the second section (85) is distributed fairly evenly to all the internal flow channels (50a) formed in the second heat transfer tube (52).

[0094] <Second heat transfer tube → First heat transfer tube> The flow of refrigerant in the connecting channel (75) when the refrigerant flows from the second heat transfer tube (52) to the first heat transfer tube (51) will be explained.

[0095] The refrigerant flowing through each internal channel (50a) of the second heat transfer tube (52) flows into and merges with the second section (85) of the connecting channel (75). The refrigerant that has merged in the second section (85) flows through the third section (90) and into the first section (80). The refrigerant that has entered the first section (80) then splits and flows into each internal channel (50a) of the first heat transfer tube (51).

[0096] As described above, the other end of the third section (90) is connected to the entire first long side (81a) of the first section (80). In addition, all the internal flow channels (50a) arranged in a line in the width direction of the first heat transfer tube (51) open to the end face of the first heat transfer tube (51) facing the first section (80). Therefore, the refrigerant flowing from the third section (90) into the first section (80) is distributed approximately evenly to all the internal flow channels (50a) formed in the first heat transfer tube (51).

[0097] -Features of Embodiment 1- In the heat exchanger unit (40) of this embodiment, when the refrigerant flows through the connecting channel (75) from the first heat transfer tube (51) to the second heat transfer tube (52), the heat transfer medium flowing through the third section (90) flows into the second section (85) from the second long side (86a, 86b) along the width direction of the second heat transfer tube (52), and is distributed approximately evenly to all of the multiple internal channel flows (50a) arranged in the width direction of the second heat transfer tube (52). Furthermore, when the refrigerant flows through the connecting channel (75) from the second heat transfer tube (52) to the first heat transfer tube (51), the heat transfer medium flowing through the third section (90) flows into the first section (80) from the first long side (81a, 81b) along the width direction of the first heat transfer tube (51), and is distributed approximately evenly to all of the multiple internal tube channels (50a) arranged in the width direction of the first heat transfer tube (51).

[0098] In the heat exchanger unit (40) of this embodiment, the refrigerant flowing through the connecting channel (75) is distributed almost evenly to all the internal channels (50a) formed in the heat transfer tube (50), and the difference in the flow rate of the refrigerant flowing through each internal channel (50a) of a single heat transfer tube (50) is kept small. Therefore, according to this embodiment, the performance of the heat exchanger unit (40) can be improved.

[0099] -Variation 1 of Embodiment 1- The connecting channel (75) formed in the second plate stack (62) of this embodiment may be a channel with the shape shown in Figure 7. In the connecting channel (75) shown in Figure 7, the third portion (90) is divided into a first end (91), a second end (92), and an intermediate portion (93).

[0100] The first end (91) is the portion that includes one end of the connecting channel (75). The first end (91) connects to the entire upper first long side (81a) of the first part (80). Thus, the first end (91) connects to the portion of the first long side (81a) that includes the midpoint (CP1) of the first long side (81a). The width of the first end (91) is substantially equal to the width Wp1 of the first part (80).

[0101] The second end (92) is the portion that includes the other end of the connecting channel (75). The second end (92) connects to the entire lower second long side (86b) of the second part (85). Thus, the second end (92) connects to the portion of the second long side (86b) that includes the midpoint (CP2) of the second long side (86b). The width of the second end (92) is substantially equal to the width Wp2 of the second part (85).

[0102] The intermediate section (93) is the part that connects the first end (91) and the second end (92). The intermediate section (93) extends linearly in a diagonal direction from the first end (91) to the second end (92). The width Wp3 of the intermediate section (93) is slightly narrower than the width Wp1 of the first section (80) and the width Wp2 of the second section (85).

[0103] -Modification 2 of Embodiment 1- The connecting channel (75) formed in the second plate stack (62) of this embodiment may be a channel with the shape shown in Figure 8. In the connecting channel (75) shown in Figure 8, the third portion (90) is divided into a first end (91), a second end (92), and an intermediate portion (93).

[0104] The first end (91) is the portion that includes one end of the connecting channel (75). The first end (91) connects to the entire upper first long side (81a) of the first part (80). Therefore, the first end (91) connects to the portion of the first long side (81a) that includes the midpoint (CP1) of the first long side (81a). The width of the first end (91) gradually narrows upward from the upper first long side (81a) of the first part (80).

[0105] The second end (92) is the portion that includes the other end of the connecting channel (75). The second end (92) connects to the entire lower second long side (86b) of the second part (85). Therefore, the second end (92) connects to the portion of the second long side (86b) that includes the midpoint (CP2) of the second long side (86b). The width of the second end (92) gradually narrows downward from the lower second long side (86b) of the second part (85).

[0106] The intermediate section (93) is the part that connects the first end (91) and the second end (92). The intermediate section (93) extends linearly in a diagonal direction from the first end (91) to the second end (92). The width Wp3 of the intermediate section (93) is significantly narrower than the width Wp1 of the first section (80) and the width Wp2 of the second section (85).

[0107] -Modification 3 of Embodiment 1- The connecting channel (75) formed in the second plate stack (62) of this embodiment may be a channel with the shape shown in Figure 9.

[0108] In the connecting channel (75) shown in Figure 9, the lower side portion (90b) is formed in a curved shape that curves upward. One end of this side portion (90b) is connected to the vicinity of the other end of the upper first long side (81a) of the first portion (80). The other end of this side portion (90b) is connected to the vicinity of the other end of the lower second long side (86b) of the second portion (85).

[0109] The center line (L1) in the width direction of the connecting channel (75) is located above the straight line (L2) that connects the midpoint (CP1) of the first long side (81a) of the first part (80) and the midpoint (CP2) of the second long side (86b) of the second part (85).

[0110] Here, during operation of the air conditioning system (10), a gaseous-liquid two-phase refrigerant may flow through the connecting channel (75). When a gaseous-liquid two-phase refrigerant flows through the connecting channel (75), the gaseous refrigerant may be unevenly distributed in the region along the upper side (90a) of the connecting channel (75), and the liquid refrigerant may be unevenly distributed in the region along the lower side (90b) of the connecting channel (75). As a result, the ratio of liquid refrigerant to gaseous refrigerant in the refrigerant flowing into each internal channel (50a) of the heat transfer tube (50) may become uneven.

[0111] On the other hand, in the connecting channel (75) of this modified example, the lower side portion (90b) is formed in a curved shape that curves upward. Also, in the connecting channel (75) of this modified example, the center line (L1) in the width direction is located above the straight line (L2) connecting the midpoint (CP1) of the first long side (81a) and the midpoint (CP2) of the second long side (86b). Therefore, when a gas-liquid two-phase refrigerant flows through the connecting channel (75) of this modified example, the mixing ratio of gaseous and liquid refrigerant throughout the connecting channel (75) is more uniform compared to when a gas-liquid two-phase refrigerant flows through the connecting channel (75) shown in Figure 6.

[0112] Therefore, according to this modified example, it is possible to equalize the ratio of liquid refrigerant to gaseous refrigerant in the refrigerant flowing from the connecting channel (75) into each internal channel (50a) of the heat transfer tube (50).

[0113] -Modification 4 of Embodiment 1- The connecting channel (75) formed in the second plate stack (62) of this embodiment may connect one first heat transfer tube (51) to one second heat transfer tube (52) located next to the first heat transfer tube (51) one position below the first heat transfer tube (51).

[0114] In the connecting channel (75) of this modified example, one end of the third portion (90) is connected to the lower first long side (81b) of the first portion (80). One end of the third portion (90) is connected to the entire first long side (81b). Therefore, one end of the third portion (90) is connected to the portion of the first long side (81b) that includes the midpoint of the first long side (81b).

[0115] In the connecting channel (75) of this modified example, the other end of the third portion (90) is connected to the upper second long side (86a) of the second portion (85). The other end of the third portion (90) is connected to the entire second long side (86a). Therefore, the other end of the third portion (90) is connected to the portion of the second long side (86a) that includes the midpoint of the second long side (86a).

[0116] In the connecting channel (75) of this modified example, one end of the third portion (90) is connected to the lower first long side (81b) of the first portion (80), and the other end of the third portion (90) is connected to the upper second long side (86a) of the second portion (85). Therefore, the first long side (81b) of the first portion (80) to which one end of the third portion (90) is connected is located on the opposite side from the second long side (86a) of the second portion (85) to which the other end of the third portion (90) is connected. The second long side (86a) of the second portion (85) to which the other end of the third portion (90) is connected is the second long side of the pair of second long sides (86a, 86b) of the second portion (85) that is closer to the first long side (81b) of the first portion (80) to which one end of the third portion (90) is connected.

[0117] Furthermore, this modified example can also be applied to the connecting channel (75) in modified examples 1 to 3 of this embodiment.

[0118] -Modification 5 of Embodiment 1- In the connecting channel (75) of this embodiment, one end of the third portion (90) may be connected to a part of the upper first long side (81a) of the first portion (80). In this modified example, it is desirable that one end of the third portion (90) be connected to the portion of the first long side (81a) that includes the midpoint (CP1) of the first long side (81a). Also in this modified example, it is desirable that one end of the third portion (90) be connected to an area of ​​more than half of the first long side (81a).

[0119] Furthermore, this modified example can also be applied to the connecting channel (75) in modified examples 1 to 4 of this embodiment.

[0120] -Modification 6 of Embodiment 1- In the connecting channel (75) of this embodiment, the other end of the third portion (90) may be connected to a part of the lower second long side (86b) of the second portion (85). In this modified example, it is desirable that one end of the third portion (90) be connected to a portion of the second long side (86b) that includes the midpoint (CP2) of the second long side (86b). Also in this modified example, it is desirable that one end of the third portion (90) be connected to an area of ​​more than half of the second long side (86b).

[0121] Furthermore, this modified example can also be applied to the connecting channel (75) in modified examples 1 to 5 of this embodiment.

[0122] Embodiment 2 Embodiment 2 will now be described.

[0123] In the air conditioning system (10) of this embodiment, the connecting channel (75) formed in the second plate stack (62) of the heat exchanger unit (40) differs from the connecting channel (75) of Embodiment 1. Here, we will mainly explain the differences between the connecting channel (75) formed in the second plate stack (62) of this embodiment and the connecting channel (75) of Embodiment 1.

[0124] -Connection channel of the second plate stack- Figure 10 shows a cross-section of the portion of the second plate stack (62) that connects to the heat transfer tube (50) of the first heat exchange section (46). In Figure 10, the 10A-10A section is the cross-section along the cutting line indicated in the 10B-10B section. Similarly, the 10B-10B section is the cross-section along the cutting line indicated in the 10A-10A section.

[0125] As shown in Figure 10, the connecting channel (75) in this embodiment connects one first heat transfer tube (51) to one second heat transfer tube (52) located next to the first heat transfer tube (51). Therefore, the connecting channel (75) in this embodiment connects one first heat transfer tube (51) to one second heat transfer tube (52) that is closest to the first heat transfer tube (51). The connecting channel (75) in this embodiment is formed in the first plate (71), similar to the connecting channel (75) in Embodiment 1.

[0126] As shown in Figure 11, the connecting channel (75) is divided into a first part (80), a second part (85), and a third part (90).

[0127] <Part 1> The first part (80) of this embodiment has the same shape as the first part (80) of Embodiment 1. Similar to the first part (80) of Embodiment 1, the first part (80) of this embodiment overlaps the entire end face of the first heat transfer tube (51) and covers the end face of the first heat transfer tube (51). The end face of the first heat transfer tube (51) faces the first part (80). All internal flow channels (50a) formed in the first heat transfer tube (51) communicate with the first part (80). The first part (80) has a pair of first long sides (81a, 81b) and a pair of first semicircular parts (82a, 82b).

[0128] <Second part> The second part (85) of this embodiment has the same shape as the second part (85) of Embodiment 1. However, the second heat transfer tube (52) corresponding to the second part (85) of this embodiment is located in a different position than the second heat transfer tube (52) corresponding to the second part (85) of Embodiment 1. The second part (85) of this embodiment overlaps the entire end face of the second heat transfer tube (52) and covers the end face of the second heat transfer tube (52), similar to the second part (85) of Embodiment 1. The end face of the second heat transfer tube (52) faces the second part (85). All internal flow channels (50a) formed in the second heat transfer tube (52) communicate with the second part (85). The second part (85) has a pair of second long sides (86a, 86b) and a pair of second semicircular parts (87a, 87b).

[0129] <3rd part> The third section (90) is the section that connects the first section (80) and the second section (85). The third section (90) is connected to both the first section (80) and the second section (85).

[0130] The third section (90) is a V-shaped channel located below the first section (80) and the second section (85). A flat straight section (94) is formed at the bottom of the V-shaped third section (90). The straight section (94) faces the first long side (81b) on the lower side of the first section (80) and also faces the second long side (86b) on the lower side of the second section (85).

[0131] One end of the third part (90) connects to the lower first long side (81b) of the first part (80). Therefore, one end of the third part (90) connects to only one of the pair of first long sides (81a, 81b) of the first part (80). Also, one end of the third part (90) connects to the entire first long side (81b). Therefore, one end of the third part (90) connects to the portion of the first long side (81b) that includes the midpoint (CP1) of the first long side (81b).

[0132] The other end of the third part (90) connects to the lower second long side (86b) of the second part (85). Therefore, the other end of the third part (90) connects to only one of the pair of second long sides (86a, 86b) of the second part (85). Also, the other end of the third part (90) connects to the entire second long side (86b). Therefore, the other end of the third part (90) connects to the portion of the second long side (86b) that includes the midpoint (CP2) of the second long side (86b).

[0133] One end of the third part (90) is connected to the lower first long side (81b) of the first part (80), and the other end of the third part (90) is connected to the lower second long side (86b) of the second part (85). Therefore, the first long side (81b) of the first part (80) to which one end of the third part (90) is connected is located on the same side as the second long side (86b) of the second part (85) to which the other end of the third part (90) is connected. The second long side (86b) of the second part (85) to which the other end of the third part (90) is connected is the second long side of the pair of second long sides (86a, 86b) of the second part (85) that is closer to the first long side (81b) of the first part (80) to which one end of the third part (90) is connected.

[0134] -Refrigerant flow in the connecting channel- In the connecting channel (75) of the second plate stack (62), the refrigerant flows from one of the first heat transfer tubes (51) and the second heat transfer tube (52) to the other, similar to the first embodiment.

[0135] <First heat transfer tube → Second heat transfer tube> The flow of refrigerant in the connecting channel (75) when the refrigerant flows from the first heat transfer tube (51) to the second heat transfer tube (52) will be explained.

[0136] The refrigerant flowing through each internal channel (50a) of the first heat transfer tube (51) flows into and merges with the first section (80) of the connecting channel (75). The refrigerant that has merged in the first section (80) flows through the third section (90) and into the second section (85). The refrigerant that has entered the second section (85) splits and flows into each internal channel (50a) of the second heat transfer tube (52).

[0137] As described above, the other end of the third section (90) is connected to the entire second long side (86b) of the second section (85). In addition, all the internal flow channels (50a) arranged in a line in the width direction of the second heat transfer tube (52) open to the end face of the second heat transfer tube (52) facing the second section (85). Therefore, the refrigerant flowing from the third section (90) into the second section (85) is distributed fairly evenly to all the internal flow channels (50a) formed in the second heat transfer tube (52).

[0138] <Second heat transfer tube → First heat transfer tube> The flow of refrigerant in the connecting channel (75) when the refrigerant flows from the second heat transfer tube (52) to the first heat transfer tube (51) will be explained.

[0139] The refrigerant flowing through each internal channel (50a) of the second heat transfer tube (52) flows into and merges with the second section (85) of the connecting channel (75). The refrigerant that has merged in the second section (85) flows through the third section (90) and into the first section (80). The refrigerant that has entered the first section (80) then splits and flows into each internal channel (50a) of the first heat transfer tube (51).

[0140] As described above, the other end of the third section (90) is connected to the entire first long side (81b) of the first section (80). In addition, all the internal flow channels (50a) arranged in a line in the width direction of the first heat transfer tube (51) open to the end face of the first heat transfer tube (51) facing the first section (80). Therefore, the refrigerant flowing from the third section (90) into the first section (80) is distributed approximately evenly to all the internal flow channels (50a) formed in the first heat transfer tube (51).

[0141] -Features of Embodiment 2- In the heat exchanger unit (40) of this embodiment, similar to the heat exchanger unit (40) of Embodiment 1, the refrigerant flowing through the connecting channel (75) is distributed almost evenly to all the internal channels (50a) formed in the heat transfer tube (50), and the difference in the flow rate of the refrigerant flowing through each internal channel (50a) of a single heat transfer tube (50) is kept small. Therefore, according to this embodiment, the performance of the heat exchanger unit (40) can be improved.

[0142] -Modification 1 of Embodiment 2- The connecting channel (75) formed in the second plate stack (62) of this embodiment may be a channel with the shape shown in Figure 12. In this modified example, the shape of the third portion (90) of the connecting channel (75) differs from that of the connecting channel (75) in Figure 11.

[0143] The third part (90) of this modified example is a U-shaped channel located below the first part (80) and the second part (85). A flat straight section (94) is formed at the bottom of the U-shaped third part (90). This straight section (94) faces the first long side (81b) on the lower side of the first part (80) and the second long side (86b) on the lower side of the second part (85), similar to the straight section (94) of the connecting channel (75) shown in Figure 11.

[0144] -Modification 2 of Embodiment 2- The connecting channel (75) formed in the second plate stack (62) of this embodiment may be a channel with the shape shown in Figure 13. In this modified example, the shape of the third portion (90) of the connecting channel (75) differs from that of the connecting channel (75) in Figure 11.

[0145] The third part (90) of this modified example is a U-shaped channel located below the first part (80) and the second part (85). The side wall of the third part (90) of this modified example is curved throughout. Therefore, no flat straight section (94) is formed in the third part (90) of this modified example.

[0146] -Modification 2 of Embodiment 2- In the connecting channel (75) formed in the second plate stack (62) of this embodiment, the third portion (90) may be located above the first portion (80) and the second portion (85).

[0147] In the connecting channel (75) of this modified example, one end of the third portion (90) is connected to the upper first long side (81a) of the first portion (80). One end of the third portion (90) is connected to the entire first long side (81a). Therefore, one end of the third portion (90) is connected to the portion of the first long side (81a) that includes the midpoint of the first long side (81a).

[0148] The other end of the third part (90) connects to the upper second long side (86a) of the second part (85). The other end of the third part (90) connects to the entire second long side (86a). Therefore, the other end of the third part (90) connects to the portion of the second long side (86a) that includes the midpoint of the second long side (86a).

[0149] One end of the third part (90) is connected to the upper first long side (81a) of the first part (80), and the other end of the third part (90) is connected to the upper second long side (86a) of the second part (85). Therefore, the first long side (81a) of the first part (80) to which one end of the third part (90) is connected is located on the same side as the second long side (86a) of the second part (85) to which the other end of the third part (90) is connected. The second long side (86a) of the second part (85) to which the other end of the third part (90) is connected is the second long side of the pair of second long sides (86a, 86b) of the second part (85) that is closer to the first long side (81a) of the first part (80) to which one end of the third part (90) is connected.

[0150] -Modification 3 of Embodiment 2- In the connecting channel (75) of this embodiment, one end of the third portion (90) may be connected to a part of the lower first long side (81b) of the first portion (80). In this modified example, it is desirable that one end of the third portion (90) be connected to the portion of the first long side (81b) that includes the midpoint (CP1) of the first long side (81b). Also in this modified example, it is desirable that one end of the third portion (90) be connected to an area of ​​more than half of the first long side (81b).

[0151] Furthermore, this modified example can also be applied to the connecting channel (75) in modified examples 1 and 2 of this embodiment.

[0152] -Modification 4 of Embodiment 2- In the connecting channel (75) of this embodiment, the other end of the third portion (90) may be connected to a part of the lower second long side (86b) of the second portion (85). In this modified example, it is desirable that one end of the third portion (90) be connected to a portion of the second long side (86b) that includes the midpoint (CP2) of the second long side (86b). Also in this modified example, it is desirable that one end of the third portion (90) be connected to an area of ​​more than half of the second long side (86b).

[0153] Furthermore, this modified example can also be applied to the connecting channel (75) in modified examples 1 to 3 of this embodiment.

[0154] Embodiment 3 Embodiment 3 will now be described.

[0155] The air conditioning system (10) of this embodiment differs from the air conditioning system (10) of Embodiment 1 in the configuration of the heat exchanger unit (40). Here, we will mainly explain the differences between the heat exchanger unit (40) of this embodiment and the heat exchanger unit (40) of Embodiment 1.

[0156] - Arrangement of heat transfer tubes - As shown in Figure 14, the arrangement of heat transfer tubes (50) in each heat exchange section (46, 47, 48) of the heat exchanger unit (40) of this embodiment differs from that of the heat exchanger unit of Embodiment 1. In each heat exchange section (46, 47, 48) of this embodiment, the positions of each first heat transfer tube (51) and the second heat transfer tube (52) closest to each first heat transfer tube (51) are different in the direction of the long side of the fin (53). In the direction of the long side of the fin (53), the position of each first heat transfer tube (51) constituting the first tube row (56) is shifted by half the pitch of the multiple first heat transfer tubes (51) in the first tube row (56) relative to the position of each second heat transfer tube (52) constituting the second tube row (57).

[0157] -Connection channel of the second plate stack- In this embodiment, a connecting channel (75) is formed in the second plate stack (62), similar to the first embodiment. The connecting channel (75) connects one first heat transfer tube (51) to one second heat transfer tube (52) that is closest to the first heat transfer tube (51). In this embodiment, the connecting channel (75) connects one first heat transfer tube (51) to one of the two second heat transfer tubes (52) that are closest to the first heat transfer tube (51), specifically the one located above the first heat transfer tube (51).

[0158] The connecting channel (75) in this embodiment is formed in the same shape as the connecting channel (75) in Embodiment 1 shown in Figure 6. The connecting channel (75) is divided into a first part (80), a second part (85), and a third part (90), similar to the connecting channel (75) in Embodiment 1.

[0159] <Part 1> The first part (80) of this embodiment has the same shape as the first part (80) of Embodiment 1. Similar to the first part (80) of Embodiment 1, the first part (80) of this embodiment overlaps the entire end face of the first heat transfer tube (51) and covers the end face of the first heat transfer tube (51). The end face of the first heat transfer tube (51) faces the first part (80). All internal flow channels (50a) formed in the first heat transfer tube (51) communicate with the first part (80). The first part (80) has a pair of first long sides (81a, 81b) and a pair of first semicircular parts (82a, 82b).

[0160] <Second part> The second part (85) of this embodiment has the same shape as the second part (85) of Embodiment 1. Similar to the second part (85) of Embodiment 1, the second part (85) of this embodiment overlaps the entire end face of the second heat transfer tube (52) and covers the end face of the second heat transfer tube (52). The end face of the second heat transfer tube (52) faces the second part (85). All internal flow channels (50a) formed in the second heat transfer tube (52) communicate with the second part (85). The second part (85) has a pair of second long sides (86a, 86b) and a pair of second semicircular parts (87a, 87b).

[0161] <3rd part> The third part of this embodiment, like the third part of Embodiment 1, extends linearly in an oblique direction from the first part (80) toward the second part (85), connecting the first part (80) and the second part (85).

[0162] One end of the third part (90) connects to the entire first long side (81a). Therefore, one end of the third part (90) connects to the portion of the first long side (81a) that includes the midpoint (CP1) of the first long side (81a). The other end of the third part (90) connects to the entire second long side (86b). Therefore, the other end of the third part (90) connects to the portion of the second long side (86b) that includes the midpoint (CP2) of the second long side (86b).

[0163] One end of the third part (90) is connected to the upper first long side (81a) of the first part (80), and the other end of the third part (90) is connected to the lower second long side (86b) of the second part (85). Therefore, the first long side (81a) of the first part (80) to which one end of the third part (90) is connected is located on the opposite side from the second long side (86b) of the second part (85) to which the other end of the third part (90) is connected. The second long side (86b) of the second part (85) to which the other end of the third part (90) is connected is the second long side of the pair of second long sides (86a, 86b) of the second part (85) that is closer to the first long side (81a) of the first part (80) to which one end of the third part (90) is connected.

[0164] -Refrigerant flow in the connecting channel- The flow of refrigerant in the connecting channel (75) of this embodiment is the same as the flow of refrigerant in the connecting channel (75) of Embodiment 1.

[0165] When the refrigerant flows from the first heat transfer tube (51) to the second heat transfer tube (52), the refrigerant that flows from each internal flow path (50a) of the first heat transfer tube (51) into the first section (80) flows through the third section (90) and into the second section (85), and is distributed approximately evenly to all internal flow paths (50a) formed in the second heat transfer tube (52).

[0166] When the refrigerant flows from the second heat transfer tube (52) towards the first heat transfer tube (51), the refrigerant that flows into the second section (85) from each internal flow path (50a) of the second heat transfer tube (52) flows through the third section (90) and into the first section (80), and is distributed approximately evenly to all internal flow paths (50a) formed in the first heat transfer tube (51).

[0167] -Features of Embodiment 3- In the heat exchanger unit (40) of this embodiment, similar to the heat exchanger unit (40) of Embodiment 1, the refrigerant flowing through the connecting channel (75) is distributed almost evenly to all the internal channels (50a) formed in the heat transfer tube (50), and the difference in the flow rate of the refrigerant flowing through each internal channel (50a) of a single heat transfer tube (50) is kept small. Therefore, according to this embodiment, the performance of the heat exchanger unit (40) can be improved.

[0168] -Modification 1 of Embodiment 3- In this embodiment, the connecting channel (75) formed in the second plate stack (62) may connect one first heat transfer tube (51) to one of the two second heat transfer tubes (52) that are closest to the first heat transfer tube (51), specifically the one located below the first heat transfer tube (51).

[0169] In the connecting channel (75) of this modified example, one end of the third portion (90) is connected to the lower first long side (81b) of the first portion (80). One end of the third portion (90) is connected to the entire first long side (81b). Therefore, one end of the third portion (90) is connected to the portion of the first long side (81b) that includes the midpoint of the first long side (81b).

[0170] In the connecting channel (75) of this modified example, the other end of the third portion (90) is connected to the upper second long side (86a) of the second portion (85). The other end of the third portion (90) is connected to the entire second long side (86a). Therefore, the other end of the third portion (90) is connected to the portion of the second long side (86a) that includes the midpoint of the second long side (86a).

[0171] In the connecting channel (75) of this modified example, one end of the third portion (90) is connected to the lower first long side (81b) of the first portion (80), and the other end of the third portion (90) is connected to the upper second long side (86a) of the second portion (85). Therefore, the first long side (81b) of the first portion (80) to which one end of the third portion (90) is connected is located on the opposite side from the second long side (86a) of the second portion (85) to which the other end of the third portion (90) is connected. The second long side (86a) of the second portion (85) to which the other end of the third portion (90) is connected is the second long side of the pair of second long sides (86a, 86b) of the second portion (85) that is closer to the first long side (81b) of the first portion (80) to which one end of the third portion (90) is connected.

[0172] -Modification 2 of Embodiment 3- Modifications 1 to 3 of Embodiment 1 can be applied to the connecting channel (75) of this embodiment. In other words, the shape of the connecting channel (75) of this embodiment may be the same as the connecting channel (75) shown in Figures 7 to 9.

[0173] -Modification 3 of Embodiment 3- In the connecting channel (75) of this embodiment, one end of the third portion (90) may be connected to a part of the upper first long side (81a) of the first portion (80). In this modified example, it is desirable that one end of the third portion (90) be connected to the portion of the first long side (81a) that includes the midpoint (CP1) of the first long side (81a). Also in this modified example, it is desirable that one end of the third portion (90) be connected to an area of ​​more than half of the first long side (81a).

[0174] Furthermore, this modified example can also be applied to the connecting channel (75) in modified examples 1 and 2 of this embodiment.

[0175] -Modification 4 of Embodiment 3- In the connecting channel (75) of this embodiment, the other end of the third portion (90) may be connected to a part of the lower second long side (86b) of the second portion (85). In this modified example, it is desirable that one end of the third portion (90) be connected to a portion of the second long side (86b) that includes the midpoint (CP2) of the second long side (86b). Also in this modified example, it is desirable that one end of the third portion (90) be connected to an area of ​​more than half of the second long side (86b).

[0176] Furthermore, this modified example can also be applied to the connecting channel (75) in modified examples 1 to 3 of this embodiment.

[0177] Other embodiments The heat exchanger unit of the above embodiment may be modified as follows. Note that the following modifications may be combined or substituted as appropriate, as long as they do not impair the function of the heat exchanger unit.

[0178] -First variation- In each of the above embodiments 1 to 3, the second plate laminate (62) may comprise four plate members (65).

[0179] The second plate laminate (62) of this modified example will be described with reference to Figure 16. Figure 16 shows the modified example applied to the second plate laminate (62) of Embodiment 1. Here, the differences between the second plate laminate (62) of this modified example and the second plate laminate (62) of Embodiment 1 will be mainly explained.

[0180] Figure 16 shows a cross-section of the portion of the second plate stack (62) that connects to the heat transfer tubes (50) of the first heat exchange section (46). In Figure 16, the 16A-16A and 16B-16B sections are cross-sections along the cutting lines indicated in the 16C-16C and 16D-16D sections. Similarly, the 16C-16C and 16D-16D sections are cross-sections along the cutting lines indicated in the 16A-16A and 16B-16B sections.

[0181] The second plate laminate (62) of this modified example comprises a base plate (70), a first plate (71), a second plate (72), and a third plate (73). The third plate (73) is a plate member (65). The third plate (73) is formed in a flat plate shape, similar to the base plate (70), the first plate (71), and the second plate (72).

[0182] In the second plate laminate (62), the base plate (70), first plate (71), second plate (72), and third plate (73) are arranged in order from the side closest to the heat transfer tube (50). The base plate (70) is joined to the first plate (71), the first plate (71) to the second plate (72), and the second plate (72) to the third plate (73) by brazing.

[0183] In the second plate laminate (62) of this modified example, the connecting channel (75) is formed by both the first plate (71) and the second plate (72). The third plate (73) covers the connecting channel (75) of the second plate (72) and seals the connecting channel (75).

[0184] The first portion (80) and the second portion (85) of the connecting channel (75) are each formed across both the first plate (71) and the second plate (72). The third portion (90) of the connecting channel (75) is formed on the second plate (72). In this modified example, the third portion (90) is formed only on the second plate (72) of the two plates (71 and 72).

[0185] -Second variation- In each of the above embodiments 1 to 3, the width Wp1 of the first portion (80) constituting the connecting channel (75) may be wider than the width Wt of the first heat transfer tube (51).

[0186] Furthermore, in each of the above embodiments 1 to 3, the width Wp2 of the second portion (85) constituting the connecting channel (75) may be wider than the width Wt of the second heat transfer tube (52).

[0187] -Third variation- In each of the above embodiments 1 to 3, the first portion (80) constituting the connecting channel (75) may overlap with a part of the end face of the first heat transfer tube (51). If the condition that "the first portion (80) communicates with all the internal channels (50a) formed in the first heat transfer tube (51)" is met, a part of the end face of the first heat transfer tube (51) may be outside the first portion (80).

[0188] -Fourth variation- In each of the above embodiments 1 to 3, the second portion (85) constituting the connecting channel (75) may overlap with a part of the end face of the second heat transfer tube (52). If the condition that "the second portion (85) communicates with all the internal channels (50a) formed in the second heat transfer tube (52)" is met, a part of the end face of the second heat transfer tube (52) may be outside the second portion (85).

[0189] -Fifth variation- In the above embodiment 1 or 2, the connecting channel (75) may connect one first heat transfer tube (51) to one second heat transfer tube (52) located next to the first heat transfer tube (51) two (or three or more) above the first heat transfer tube (51).

[0190] Furthermore, in the above embodiment 1 or 2, the connecting channel (75) may connect one first heat transfer tube (51) to one second heat transfer tube (52) located next to two (or three or more) first heat transfer tubes (51) below the first heat transfer tube (51).

[0191] -Sixth variation- In each of the above embodiments 1 to 3, the outdoor heat exchanger (22) of the outdoor unit (20) may be composed of a heat exchanger unit (40).

[0192] While embodiments and modifications have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims. Furthermore, elements of the embodiments, modifications, and other embodiments described above may be combined or substituted as appropriate. In addition, the designations "first," "second," "third," etc. in the specification and claims are used to distinguish the phrases to which these designations are given, and do not limit the number or order of such phrases. [Industrial applicability]

[0193] As described above, this disclosure is useful for heat exchanger units, air conditioning indoor units, and refrigeration cycle systems. [Explanation of Symbols]

[0194] 10. Air conditioning system (refrigeration cycle system) 11 Refrigerant Circuit () 30 Indoor unit (Air conditioning indoor unit) 40 Heat exchanger unit 50 heat transfer tubes 50a Pipe flow path 51. First heat transfer tube 52. Second heat transfer tube 53 Fins 56 1st tube row 57 2nd tube row 62. Second plate laminate (plate structure) 65 Plate Member 71 First plate (first plate component) 72. Second plate (second plate component) 75 Connection channel 80 Part 1 81a First long side 81b First long side CP1 (midpoint of the first long side) 85 Part 2 86a Second long side 86b Second long side CP2 (midpoint of the second long side) 90 Part 3 L1 (Center line of the connecting channel)

Claims

1. A heat exchanger unit (40) comprising multiple fins (53) and multiple heat transfer tubes (50), wherein the heat transfer medium flowing through the heat transfer tubes (50) exchanges heat with air, Each of the multiple heat transfer tubes (50) is a flattened tube with multiple internal flow channels (50a) formed inside it. In each of the multiple heat transfer tubes (50), the multiple internal tube channels (50a) are arranged in a line in the width direction of the heat transfer tube (50), The plurality of heat transfer tubes (50) include a plurality of first heat transfer tubes (51) and a plurality of second heat transfer tubes (52), Multiple first heat transfer tubes (51) arranged in a line with spacing between them form a first tube row (56), and multiple second heat transfer tubes (52) arranged in a line with spacing between them form a second tube row (57). The first row of pipes (56) and the second row of pipes (57) are arranged in order from upstream to downstream in the airflow passing through the heat exchanger unit (40), The plate structure (62) is joined to the ends of multiple heat transfer tubes (50) and has a connecting channel (75) formed inside that connects one first heat transfer tube (51) to one second heat transfer tube (52), The above connecting channel (75) is The end face of the first heat transfer tube (51) faces the first portion (80) through which all the internal flow channels (50a) formed in the first heat transfer tube (51) are connected, The end face of the second heat transfer tube (52) faces the second portion (85) through which all the internal flow channels (50a) formed in the second heat transfer tube (52) are connected, It has a third part (90) that communicates with both the first part (80) and the second part (85), The first portion (80) has a pair of first long sides (81a, 81b) along the width direction of the first heat transfer tube (51), The second portion (85) has a pair of second long sides (86a, 86b) along the width direction of the second heat transfer tube (52), One end of the third portion (90) is connected to only one of the pair of first long sides (81a, 81b) of the first portion (80), The other end of the third portion (90) is connected to only one of the pair of second long sides (86a, 86b) of the second portion (85). Heat exchanger unit.

2. The above plate structure (62) has a plurality of plate members (65) that overlap and are joined to each other. The first portion (80), the second portion (85), and the third portion (90) of the above-mentioned connecting channel (75) are formed on a single plate member (65). The heat exchanger unit according to claim 1.

3. The above plate structure (62) has a plurality of plate members (65) that overlap and are joined to each other. The plurality of plate members (65) include a first plate member (71) and a second plate member (72) located on the opposite side of the first plate member (71) from the heat transfer tube (50). The first portion (80) and the second portion (85) of the above-mentioned connecting channel (75) are formed across both the first plate member (71) and the second plate member (72), The third portion (90) of the connecting channel (75) is formed only on the second plate member (72) of the first plate member (71) and the second plate member (72). The heat exchanger unit according to claim 1.

4. The width of the first part (80) described above is greater than or equal to the width of the first heat transfer tube (51), The width of the second part (85) described above is greater than or equal to the width of the second heat transfer tube (52), The width of the third portion (90) is less than or equal to the width of the first heat transfer tube (51) and less than or equal to the width of the second heat transfer tube (52). A heat exchanger unit according to any one of claims 1 to 3.

5. The first long side (81a, 81b) of the first part (80), to which one end of the third part (90) is connected, is located on the same side as the second long side (86a, 86b) of the second part (85), to which the other end of the third part (90) is connected. A heat exchanger unit according to any one of claims 1 to 3.

6. The third portion (90) has a straight section (94) formed opposite the first long side (81a, 81b) and the second long side (86a, 86b). The heat exchanger unit according to claim 5.

7. The first long side (81a, 81b) of the first part (80), to which one end of the third part (90) is connected, is located on the opposite side from the second long side (86a, 86b) of the second part (85), to which the other end of the third part (90) is connected. A heat exchanger unit according to any one of claims 1 to 3.

8. The center line (L1) in the width direction of the connecting channel (75) is located above the straight line (L2) that connects the midpoint (CP1) of the first long side (81a, 81b) to which one end of the third portion (90) is connected, and the midpoint (CP2) of the second long side (86a, 86b) to which the other end of the third portion (90) is connected. The heat exchanger unit according to claim 7.

9. One end of the third portion (90) is connected to the portion of the first long side (81a, 81b) that includes the midpoint (CP1) of the first long side (81a, 81b), The other end of the third portion (90) is connected to the portion of the second long side (86a, 86b) that includes the midpoint (CP2) of the second long side (86a, 86b). A heat exchanger unit according to any one of claims 1 to 3.

10. A heat exchanger unit (40) comprising any one of claims 1 to 3, In the heat exchanger unit (40) described above, the heat transfer medium is used to exchange heat with indoor air. Indoor unit of an air conditioner.

11. A refrigerant circuit (11) having one of the heat exchanger units (40) according to claims 1 to 3, In the refrigerant circuit (11) described above, the refrigerant is circulated to perform a refrigeration cycle. Refrigeration cycle device.

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