Heat exchanger

Abstract

To suppress the deviation of thermal load in a plurality of internal flow paths while securing the rigidity of fins by using residual parts.SOLUTION: A heat exchanger includes a plurality of flat tubes 1 having a plurality of internal flow paths L formed along the tube axial direction, and fins 2 where a plurality of long-sized slits S into which the flat tubes 1 are inserted, respectively, are formed ranging from a first long-side part 21 extending in the longitudinal direction midway through a second long-side part 22 on the opposite side to the first long-side part 21, extending in the longitudinal direction, and whose residual parts ranging from terminal ends S1 of the slits S to the second long-side part 22 continue with each other in the longitudinal direction. The flow path cross section of one of the internal flow paths L of the flat tubes 1, located nearest to the second long-side part 22 side, is larger than the flow path cross section of the other located closer to the first long-side part 21 side than the internal flow path L.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a heat exchanger. [Background technology]

[0002] 2. Description of the Related Art As shown in Patent Document 1, a conventional heat exchanger uses a plurality of flat tubes, each having a plurality of internal flow paths, as heat transfer tubes in order to improve heat exchange efficiency.

[0003] These flat tubes are arranged, for example, in multiple tiers, one above the other, and are inserted into a plurality of notches formed in elongated fins extending in the vertical direction.

[0004] The notch is formed from one long side of the fin halfway to the other long side, so that a continuation remains in the longitudinal direction from the notch to the other long side.

[0005] In such a configuration, the remaining portion continuing in the longitudinal direction needs to be designed to have a length sufficient to ensure the rigidity of the fin.

[0006] However, extending the remaining portion to a certain extent in this manner leads to an excessively large heat transfer area, and the amount of heat exchange between the fluid flowing through the internal flow paths of the flat tube that are closest to the remaining portion and this remaining portion increases, resulting in an uneven distribution of heat load in the multiple internal flow paths. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2005-127597 A Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, the present invention has been made to solve the above-described problems all at once, and the main object thereof is to suppress the bias of the heat load in a plurality of internal flow paths while ensuring the rigidity of the fins by the remaining portion.

Means for Solving the Problems

[0009] That is, the heat exchanger according to the present invention includes a plurality of flat tubes in which a plurality of internal flow paths are formed along the tube axis direction, and a plurality of slits that are long and into which each of the flat tubes is inserted are formed from a first long side portion extending in the longitudinal direction to a second long side portion extending in the longitudinal direction on the side opposite to the first long side portion, and a fin in which the remaining portion from the abutting portion of the slit to the second long side portion is connected in the longitudinal direction. Among the internal flow paths of the flat tube, the flow path cross section of the one located closest to the second long side portion is larger than the flow path cross section of the one located closer to the first long side portion than this internal flow path.

[0010] In the heat exchanger configured as described above, the internal flow path located closest to the second long side portion has a large heat load because it is closest to the remaining portion, but the flow path cross section of this internal flow path is larger than the flow path cross section of the internal flow path located closer to the first long side portion where the heat load is smaller than this internal flow path. Therefore, for each internal flow path, it is possible to secure a refrigerant flow rate corresponding to the heat load, and it is possible to suppress the bias of the heat load.

[0011] Here, when the flat surface of the flat tube extends along the horizontal direction, if condensed water accumulates on this flat surface, it will cause a decrease in performance due to frosting of this condensed water. Therefore, it is preferable that the remaining portion is provided on the leeward side. In this case, the condensed water accumulated in the flat tube can be sent to the leeward side by the wind passing between the fins and dropped along the remaining portion. Therefore, in addition to suppressing the bias of the heat load described above, drainage performance can also be ensured. On the one hand, when the remaining part is provided on the windward side, if the wind speed is high, the condensed water that tries to fall along the remaining part may climb onto the flat tube, and the drainage performance may be inferior compared to the above-described configuration.

[0012] The temperature difference between the refrigerant and the air flowing through the internal flow path on the windward side is larger than the temperature difference between the refrigerant and the air flowing through the internal flow path on the leeward side. That is, the heat exchange amount is larger on the windward side than on the leeward side, and this also promotes the bias of the heat load. Therefore, among the internal flow paths of the flat tube, it is preferable that the flow path cross-section of the one located most on the windward side is larger than the flow path cross-section of the one located on the leeward side of this internal flow path. If so, the bias of the heat load can be further suppressed.

[0013] Focusing on each of the plurality of support portions that partition the adjacent internal flow paths, the pressure received from the refrigerant flowing through the internal flow path with a large flow path cross-section (hereinafter also referred to as a large internal flow path) is greater than the pressure received from the refrigerant flowing through the internal flow path with a small flow path cross-section (hereinafter also referred to as a small internal flow path). Therefore, it is necessary to improve the pressure resistance strength of the support portion that partitions the large internal flow path. As one aspect, it is conceivable to thicken the support portion that partitions the large internal flow path. However, considering manufacturability, it is desirable that the thickness of each support portion is uniform. Therefore, in a configuration in which the plurality of internal flow paths include a large internal flow path having a flow path cross-section larger than a predetermined cross-sectional area and a small internal flow path having a flow path cross-section smaller than the predetermined cross-sectional area, it is preferable that the R dimension of the corner portion in the flow path cross-section of the large internal flow path is larger than the R dimension of the corner portion in the flow path cross-section of the small internal flow path. If so, the root of the support portion that partitions the large internal flow path becomes thick, and the stress at this corner portion can be dispersed. Thereby, while making the thickness of each support portion uniform, the pressure resistance strength of the support portion that partitions the large internal flow path can be satisfied.

[0014] Also, when it is difficult to adjust the R dimension of the corner part described above, it is preferable that the column part adjacent to the large internal flow path is thicker than the column part adjacent to the small internal flow path. In this case, the pressure resistance strength of the column part partitioning the large internal flow path can be satisfied.

[0015] Focusing on one column part, if the R dimensions of the corner parts located on both sides of the root of this column part are different, stress concentration tends to occur on the side with the smaller R dimension. Therefore, in the flow path cross section of the internal flow path, it is preferable that the R dimensions of the corner parts located on both sides of the column part are the same. In this case, stress concentration at the root of the column part can be prevented, and while thinning the column part, the pressure resistance strength can be satisfied.

[0016] In at least one flow path cross section of the internal flow path, it is preferable that the shape of the corner part located on the windward side and the shape of the corner part located on the leeward side are asymmetric. In this case, by making the shape of the corner part a shape corresponding to the thickness of the column part, stress concentration can be prevented, and while thinning the column part, the pressure resistance strength can be satisfied.

[0017] It is preferable that the shape of the windward side and the shape of the leeward side of the flat tube are asymmetric. In this case, it is possible to prevent the flat tube from being inserted into the fin in the wrong direction.

[0018] As a specific aspect of the asymmetric shape, those in which one end portion in the width direction of the flat tube has a shape corresponding to the abutting portion of the slit can be cited.

[0019] In the flat surface of the flat tube, it is preferable that at least a part of the location above or below the internal flow path located closest to the first long side portion is in contact with the fin. In this case, the heat exchange amount between the refrigerant flowing through the internal flow path located closest to the first long side portion and the fin can be ensured, and further leveling of the heat load can be achieved.

Advantages of the Invention

[0020] According to the present invention configured as described above, while ensuring the rigidity of the fins by the remaining portions, it is possible to suppress the bias of the heat load in the plurality of internal flow paths.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Modes for Carrying Out the Invention

[0022] Hereinafter, an embodiment of the heat exchanger according to the present invention will be described with reference to the drawings.

[0023] The heat exchanger 100 according to this embodiment is used in an air conditioner having a refrigerant circuit to which a compressor, an outdoor heat exchanger, a throttling mechanism, and an indoor heat exchanger are connected, and is used for at least one of the outdoor heat exchanger and the indoor heat exchanger.

[0024] Specifically, as shown in FIG. 1, this heat exchanger 100 is a so-called fin-and-tube heat exchanger, and includes a plurality of flat tubes 1 which are heat transfer tubes through which refrigerant flows inside, and a plurality of fins 2 provided with these flat tubes 1.

[0025] As shown in FIG. 2, the flat tube 1 has a flat shape and has a plurality of internal flow paths L along the tube axis direction, and is also called a multi-hole flat tube. The flat tube 1 of this embodiment is arranged such that the flat surface 11 is horizontal, and the refrigerant is provided to flow horizontally inside it.

[0026] As shown in FIG. 1, the flat tubes 1 are arranged in multiple upper and lower stages, for example, at equal intervals and parallel to each other. In this embodiment, the flat tubes 1 arranged in multiple upper and lower stages are arranged in two rows. However, the number of rows of these flat tubes 1 may be three or more rows, or may be one row.

[0027] As shown in FIG. 1, the fin 2 has an elongated shape extending along the vertical direction, and a plurality of flat tubes 1 provided in multiple stages are inserted therein. Such fins 2 are arranged at a predetermined fin pitch along the extending direction of the flat tubes 1, and here they are arranged at equal intervals. Thereby, heat exchange is performed between the air flowing between the fins 2 and the refrigerant flowing through the internal flow path L of the flat tube 1.

[0028] In addition, as shown in FIGS. 1 and 2, the fin 2 of this embodiment includes a heat transfer enlarged surface 2x provided along the air flow direction, in other words, along the width direction of the fin 2, and a drainage structure 2y provided so as to overlap the heat transfer enlarged surface 2x.

[0029] The heat transfer enlarged surface 2x consists of a plurality of ridges and a plurality of valleys. Specifically, this fin 2 is a corrugated fin that has been corrugated processed.

[0030] The drainage structure 2y is for draining the condensed water generated when the heat exchanger 100 of the outdoor unit functions as a condenser during the heating operation from the surface of the flat tube 1 and the surface of the fin 2, and particularly for preventing the condensed water from staying on the flat surface 11 of the flat tube 1. Specifically, this drainage structure 2y includes concave portions formed by denting the surface of the fin 2 and convex portions formed by bulging the surface of the fin 2, etc. For example, it is bead-shaped or rib-shaped convex ridges formed elongated in the width direction of the fin 2.

[0031] However, as the fin 2 of this heat exchanger 100, it is not necessarily required to be equipped with the heat transfer enlarged surface 2x and the drainage structure 2y, and it may be in a flat plate shape.

[0032] As shown in FIG. 2, these fins 2 are provided corresponding to each of the flat tubes 1, and a plurality of slits S into which the flat tubes 1 are inserted are formed.

[0033] These slits S are formed from the first long side portion 21 extending in the longitudinal direction of the fin 2 to midway between the second long side portion 22 that also extends in the longitudinal direction on the side opposite to the first long side portion 21.

[0034] More specifically, each of the first long side portion 21 and the second long side portion 22 extends in the vertical direction here, and the slit S extends in the horizontal direction here.

[0035] Thereby, the slit S opens to the first long side portion 21, and a butting portion S1 that is closed between the first long side portion 21 and the second long side portion 22 is formed.

[0036] From the butting portion S1 of this slit S to the second long side portion 22, the fin 2 remains, and this remaining portion 23 is continuous in the longitudinal direction. Note that the term "continuous" as used herein means that the remaining portions 23 adjacent to each other along the longitudinal direction are connected without interruption, and also includes a concept in which one or more holes are provided between the adjacent remaining portions 23.

[0037] In this embodiment, as shown in FIG. 2, the first long side portion 21 is located on the windward side, and the second long side portion 22 is located on the leeward side. As a result, the opening of the slit S is provided on the windward side, and the remaining portion 23 of the slit S is provided on the leeward side.

[0038] However, as shown in FIG. 2, this heat exchanger 100 is configured such that, among the internal flow paths L of the flat tube 1 described above, the flow path cross-section of the one located closest to the second long side portion 22 is larger than the flow path cross-section of the one located on the first long side portion 21 side of this internal flow path L.

[0039] In other words, among the plurality of internal flow paths L, the flow path cross-section of the one closest to the remaining portion 23 is larger than the flow path cross-section of the one located on the windward side of this internal flow path L. Note that the flow path cross-section as used herein refers to a cross-section orthogonal to the flow direction of the refrigerant in the internal flow path L, and for example, has a substantially rectangular shape with four corners.

[0040] Furthermore, in this embodiment, among the plurality of internal flow paths L, the flow path cross-section of the one located most on the windward side is larger than the flow path cross-section of the one located on the leeward side of this internal flow path L.

[0041] In this way, the plurality of internal flow paths L include a plurality of types with different sizes of cross-sectional shapes. Specifically, it includes a large internal flow path L1 in which the flow path cross-section is larger than a predetermined cross-sectional area, and a small internal flow path L2 in which the flow path cross-section is smaller than the predetermined cross-sectional area.

[0042] In this embodiment, as shown in FIG. 2, at least the internal flow path L located most on the windward side and the internal flow path L located most on the leeward side and closest to the remaining portion 23 are the large internal flow paths L1, and a plurality of small internal flow paths L2 are interposed between these large internal flow paths L1.

[0043] More specifically, in this embodiment, a plurality of large internal flow paths L1 are continuously provided from the internal flow path L located on the most windward side toward the leeward side, and these large internal flow paths L1 are designed such that the cross-sectional area of the flow path gradually decreases from the windward side toward the leeward side.

[0044] Subsequently, following these plurality of large internal flow paths L1, a plurality of small internal flow paths L2 are provided toward the leeward side, and some or all of these small internal flow paths L2 have the same cross-sectional shape.

[0045] Subsequently, following these plurality of small internal flow paths L2, large internal flow paths L1 are provided again toward the leeward side. In this embodiment, there is one large internal flow path L1 located on the leeward side of the plurality of small internal flow paths L2.

[0046] Thus, in this embodiment, the cross-sectional area of the internal flow path L gradually decreases from the windward side toward the leeward side, then several with the same cross-sectional area continue, and then the cross-sectional area becomes large again.

[0047] In such a configuration where a plurality of internal flow paths L are arranged side by side, adjacent internal flow paths L are partitioned by the support portion 12.

[0048] In this embodiment, in order to ensure manufacturability, each support portion 12 has the same thickness dimension as each other. However, the thickness dimension of the support portion 12 is not limited to this and may be changed as appropriate.

[0049] In such a configuration, the flat tube 1 of this embodiment is asymmetric in shape between the windward side and the leeward side. Specifically, at least the external shape of the flat tube 1 is asymmetric between the windward side and the leeward side.

[0050] Also, looking at the size and arrangement of the plurality of internal flow paths L, the internal shape of the flat tube 1 is also asymmetric between the windward side and the leeward side.

[0051] Describing the external shape of the flat tube 1 in detail, one end portion 1a in the width direction located on the leeward side of the flat tube 1 is the end portion on the insertion direction side into the slit S, and here it has a shape corresponding to the abutting portion S1 of the slit S.

[0052] The abutting portion S1 of the present embodiment has a curved shape such as a radial shape. In order to fit one end portion 1a in the width direction of the flat tube 1 into the abutting portion S1 without play, one end portion 1a in the width direction of the flat tube 1 has a curved shape such as a semi-circular shape here.

[0053] On the other hand, the other end portion 1b in the width direction located on the windward side of the flat tube 1 has a different shape from the one end portion 1a in the width direction, and has, for example, a substantially rectangular shape.

[0054] Also, at the other end portion 1b in the width direction of the flat tube 1, as shown in FIG. 3, at least a part of the flat surface 11 is in contact with the fin 2.

[0055] Specifically, at least a part of the location above or below the internal flow path L located closest to the first long side portion 21 in the flat surface 11 of the flat tube 1 is in contact with the fin 2.

[0056] That is, the support portion 12z that partitions the internal flow path L located most on the windward side and the internal flow path L located one leeward side thereof is located on the leeward side of the most windward contact end portion Z of the contact region between the fin 2 and the flat surface 11.

[0057] In the heat exchanger 100 configured in this way, although the internal flow path L located closest to the second long side portion 22 has the largest heat load, the flow path cross-section of this internal flow path L is larger than the flow path cross-section of the internal flow path L located on the first long side portion 21 side where the heat load is smaller than this internal flow path L. For each internal flow path L, a refrigerant flow rate corresponding to the heat load can be ensured, so that the bias of the heat load can be suppressed.

[0058] Here, the graph shown in FIG. 4 is the result of comparing the heat load of the heat exchanger 100 of the present embodiment with the heat load of a heat exchanger having a uniform cross-sectional area of the internal flow path. From this result as well, it can be seen that the heat exchanger 100 according to the present embodiment can achieve heat load leveling from one end to the other end.

[0059] Further, when the flat surface 11 of the flat tube 1 extends along the horizontal direction as in the present embodiment, if condensed water accumulates on this flat surface 11, frosting of this condensed water will cause a decrease in performance. On the other hand, since the remaining portion 23 of the present embodiment is provided on the leeward side, the condensed water accumulated in the flat tube 1 can be sent to the leeward side by the wind passing between the fins 2 and dropped along the remaining portion 23. Therefore, in addition to suppressing the bias of the heat load described above, drainage performance can also be ensured.

[0060] Furthermore, among the internal flow paths L of the flat tube 1, the cross-sectional area of the flow path located on the most windward side is larger than the cross-sectional area of the flow path located on the leeward side of this internal flow path L. Therefore, for each internal flow path L, a refrigerant flow rate corresponding to the heat load can be more ensured, and the bias of the heat load can be more suppressed. This point can also be seen from the graph of FIG. 4.

[0061] Moreover, since the shape on the windward side and the shape on the leeward side of the flat tube 1 are asymmetric, it is possible to prevent the flat tube 1 from being inserted into the fins 2 in the wrong direction.

[0062] In addition, in the flat surface 11 of the flat tube 1, at least a part of the locations above and below the internal flow path L located on the most first long side portion 21 side is in contact with the fins 2. Therefore, the heat exchange amount between the refrigerant flowing through the internal flow path L located on the most first long side portion 21 side and the fins 2 can be ensured, and further heat load leveling can be achieved.

[0063] Note that the present invention is not limited to the above-described embodiment.

[0064] For example, in the above embodiment, the aspect where the remaining part 23 is on the leeward side has been described. However, as shown in FIG. 5, the remaining part 23 may be provided on the windward side. Also in this configuration, as shown in FIG. 6, it can be seen that heat load leveling is achieved when compared with a heat exchanger having a uniform cross-sectional area of the internal flow path.

[0065] Also, focusing on each of the plurality of support portions 12 that partition the adjacent internal flow paths L, the pressure received from the refrigerant flowing through the large internal flow path L1 is greater than the pressure received from the refrigerant flowing through the small internal flow path L2. From this, it is necessary to improve the pressure resistance strength of the support portion 12 that partitions the large internal flow path L1. As one aspect, it is conceivable to thicken the support portion 12 that partitions the large internal flow path L1. However, considering manufacturability, it is desirable that the thickness of each support portion 12 is uniform.

[0066] Therefore, as shown in FIG. 7, it is preferable that the R dimension of the corner portion C in the flow path cross section of the large internal flow path L1 is larger than the R dimension of the corner portion C in the flow path cross section of the small internal flow path L2. If this is the case, the base of the support portion 12 that partitions the large internal flow path L1 becomes thicker, and the stress at this corner portion C can be more dispersed. Thereby, while making the thickness of each support portion 12 uniform, the pressure resistance strength of the support portion 12 that partitions the large internal flow path L1 can be satisfied.

[0067] Furthermore, as shown in FIG. 8, it is preferable that the support portion 12 adjacent to the large internal flow path L1 is thicker than the support portion 12 adjacent to the small internal flow path L2. If this is the case, the pressure resistance strength of the support portion 12 that partitions the large internal flow path L1 can be satisfied.

[0068] Focusing on one support portion 12, if the R dimensions of the corner portions C located on both sides of the base of this support portion 12 are different, stress concentration tends to occur on the side with the smaller R dimension. Therefore, as shown in FIG. 9, in the flow path cross section of the internal flow path L, it is preferable that the R dimensions of the corner portions C located on both sides of the support portion 12 are the same. In this case, it is possible to prevent stress concentration at the base of the support portion 12, and while reducing the thickness of the support portion 12, the pressure resistance can be satisfied.

[0069] Moreover, as shown in FIG. 10, in at least one flow path cross section of the internal flow path L, it is preferable that the shape of the corner portion C located on the windward side and the shape of the corner portion C located on the leeward side are asymmetric. In this case, by making the shape of the corner portion C a shape corresponding to the thickness of the support portion 12, it is possible to prevent stress concentration, and while reducing the thickness of the support portion 12, the pressure resistance can be satisfied.

[0070] Also, as described in the above embodiment, when the external shape of the flat tube 1 is asymmetric between the windward side and the leeward side, the header into which the flat tube 1 is inserted may have a shape corresponding to the external shape of the flat tube 1. In this case, it is possible to find an insertion error of the flat tube 1 when inserting it into the header.

[0071] Furthermore, although the flat tube 1 of the above embodiment has an asymmetric shape between the windward side and the leeward side, the flat tube 1 may have a shape that is line-symmetric or point-symmetric between the shape on the windward side and the leeward side.

[0072] Furthermore, as shown in FIG. 11, in order to improve the heat exchange amount, a plurality of louvers R may be provided on the fins 2. In this case, the flat tube 1 may be configured such that the flow path cross section of the internal flow path L becomes smaller from the windward side toward the leeward side in the region where the louver R is provided. Also in this configuration, as shown in FIG. 12, it can be seen that the heat load is leveled as compared with a heat exchanger having a uniform cross-sectional area of the internal flow path.

[0073] Needless to say, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit thereof.

Explanation of reference numerals

[0074] 100 ··· Heat exchanger 1 ··· Flat tube L ··· Internal flow path 2 ··· Fin 2x ··· Heat transfer enlarged surface 2y ··· Drainage structure S ··· Slit 21 ··· First long side part 22 ··· Second long side part S1 ··· Contact part 23 ··· Remaining part L1 ··· Large internal flow path L2 ··· Small internal flow path 11 ··· Flat surface 12 ··· Support part 1a ··· One end in the width direction 1b ··· The other end in the width direction Z ··· Contact end C ··· Corner R ··· Louver

Claims

1. A plurality of flat tubes in which a plurality of internal flow paths are formed along the tube axis direction, A plurality of slits having a long shape and into which each of the flat tubes is inserted extend in the longitudinal direction, from a first long side portion located on the windward side, to a second long side portion located on the leeward side and extending in the longitudinal direction on the side opposite to the first long side portion, and are formed up to a point midway between them, and a fin in which a remaining portion from the abutting portion of the slit to the second long side portion is continuous in the longitudinal direction; The plurality of internal flow paths of the flat tube are arranged along the insertion direction into the slit, The plurality of internal flow paths are configured such that the area of each flow path cross-section becomes smaller from the most windward side toward the leeward side, and then becomes larger toward the most leeward side. A heat exchanger characterized by this.

2. The plurality of internal flow paths include a large internal flow path having a flow path cross-section larger than a predetermined cross-sectional area and a small internal flow path having a flow path cross-section smaller than the predetermined cross-sectional area, The heat exchanger according to claim 1, wherein an R dimension of a corner portion in the flow path cross-section of the large internal flow path is larger than an R dimension of a corner portion in the flow path cross-section of the small internal flow path.

3. Adjacent internal flow paths are partitioned by a support portion, The heat exchanger according to claim 2, wherein the support portion adjacent to the large internal flow path is thicker than the support portion adjacent to the small internal flow path.

4. The heat exchanger according to claim 3, wherein R dimensions of corner portions located on both sides of the support portion in the flow path cross-section of the internal flow path are the same.

5. The heat exchanger according to any one of claims 1 to 4, wherein in at least one flow path cross-section of the internal flow path, the shape of a corner portion located on the windward side and the shape of a corner portion located on the leeward side are asymmetric.

6. The heat exchanger according to any one of claims 1 to 5, wherein the shape of the windward side of the flat tube and the shape of the leeward side are asymmetric.

7. The heat exchanger according to any one of claims 1 to 6, wherein one end portion in the width direction of the flat tube has a shape corresponding to the abutting portion of the slit.

8. The heat exchanger according to any one of claims 1 to 7, wherein at least a part of a location above or below the internal flow path located closest to the first long side portion side in the flat plane of the flat tube is in contact with the fin.

Images