Serpentine heat exchanger

Abstract

Provided in an embodiment of the present invention is a serpentine heat exchanger comprising: serpentine tubes in which a first fluid flows, and which are bent multiple times to form a serpentine flow path; fins arranged between the serpentine tubes; an inlet pipe connected to one end of the serpentine tube so as to supply the first fluid to the serpentine tube; and an outlet pipe connected to the other end of the serpentine tube so as to discharge the first fluid from the serpentine tube, wherein the serpentine tubes form a plurality of rows aligned in the flow direction of a second fluid, which exchanges heat with the first fluid, and thus the serpentine heat exchanger composed of the serpentine tubes is formed in multiple rows so that additional manufacturing thereof is simple and heat exchange efficiency is improved.

Description

[Technical Field]

[0001] The present disclosure relates to a serpentine heat exchanger, and more particularly, to a serpentine heat exchanger composed of a serpentine tube with a plurality of rows.[Background Art]

[0002] A serpentine heat exchanger is a type of heat exchanger in which a tube is arranged in a zigzag shape (i.e., a meandering shape) and fins are arranged between adjacent tube portions. Due to the structural characteristics of the bending (bent) tube, the number of brazing points can be reduced, thereby improving productivity and enhancing heat-exchange performance. (See FIG. 1)

[0003] However, a serpentine heat exchanger disclosed in Patent Document KR1020130036762, which is hereby incorporated by reference, is composed of a single row, the volume (or size) has to be increased vertically in order to expand the heat transfer area. Moreover, as a heat exchange fluid passes vertically through the single row, there is a limitation in extending the heat exchange time.

[0004] In addition, in the case of a heat exchanger disclosed in Patent Document CN104613709B, which is hereby incorporated by reference, since a single row is formed by overlapping two serpentine tubes, it has a structural limitation in securing the heat transfer area.

[0005] Meanwhile, a microchannel heat exchanger is a type of heat exchanger including multiple tiny refrigerant channels, which is known to have a reduced refrigerant charge, simple design and manufacturing processes, and high heat-exchange efficiency relative to its volume. (See FIG. 2)

[0006] However, in the case of a microchannel heat exchanger disclosed in Patent Document KR101518205B1, which is hereby incorporated by reference, a header is inevitably required to connect adjacent rows, resulting in the loss of heat transfer area. Patent Document 1: KR1020130036762 Patent Document 2: KR101518205B1 Patent Document 3: CN104613709B [Disclosure][Technical Problem]

[0007] An object of the present disclosure is to provide a serpentine heat exchanger that facilitates scalable manufacturing and improves heat exchange efficiency.

[0008] Another object of the present disclosure is to provide a serpentine heat exchanger capable of reducing the loss of heat transfer area due to a header.

[0009] Yet another object of the present disclosure is to provide a serpentine heat exchanger that is easy to configure a flow path even when a single header is used.

[0010] Yet another object of the present disclosure is to provide a serpentine heat exchanger having variability (or flexibility) through modular manufacturing units.

[0011] Yet another object of the present disclosure is to provide a serpentine heat exchanger in which adjacent rows do not adhere to each other due to thermal deformation.

[0012] The objects of the present disclosure are not limited to the objects described above, and other objects not stated herein will be clearly understood by those skilled in the art from the following description.[Technical Solution]

[0013] In accordance with an aspect of the present disclosure, the above and other objects can be accomplished by providing a serpentine heat exchanger including: a serpentine tube in which a first fluid flows and bent multiple times to define a meandering flow path; a fin disposed between adjacent portions of the serpentine tube; an inlet pipe connected to one end of the serpentine tube so as to supply the first fluid to the serpentine tube; and an outlet pipe connected to another end of the serpentine tube so as to discharge the first fluid from the serpentine tube. The serpentine tube may form a plurality of rows arranged in a flow direction of a second fluid that exchanges heat with the first fluid.

[0014] Accordingly, as the serpentine heat exchanger composed of the serpentine tube is provided in a multi-row structure, it is possible to provide a serpentine heat exchanger that facilitates scalable manufacturing and improves heat exchange efficiency.

[0015] Each of the plurality of rows formed by the serpentine tube may include: an inlet portion that defines one end portion of the serpentine tube into which the first fluid is introduced; and an outlet portion that defines another end portion of the serpentine tube from which the first fluid is discharged. The serpentine heat exchanger may further include a connecting part to connect the inlet portion and the outlet portion of adjacent rows. The connecting part may include: an inlet header in communication with the inlet pipe; and an outlet header in communication with the outlet pipe. The inlet header and the outlet header may each be configured as a single header.

[0016] Accordingly, by connecting multiple rows using a single header, it is possible to significantly increase the heat transfer area and reduce manufacturing costs, compared to a conventional configuration in which a plurality of headers are respectively connected to individual rows in the multiple rows.

[0017] The inlet portion and the outlet portion of the serpentine tube may be coupled to the inlet header and the outlet header in a fitting manner. Accordingly, it is possible to improve the manufacturing convenience of the serpentine heat exchanger.

[0018] The plurality of rows may be at least three rows, and each of the inlet header and the outlet header may include therein a partition wall to separate the rows. Accordingly, the internal partition wall structure enables a flow path through multiple rows to be simply formed using only a single header.

[0019] The inlet pipe may be connected to, among the plurality of rows, a rear row with respect to the flow direction of the second fluid, and the outlet pipe may be connected to, among the plurality of rows, a front row with respect to the flow direction of the second fluid.

[0020] Accordingly, by allowing the first fluid to flow from the rear row to the front row, a counterflow relationship may be achieved between the second fluid and the first fluid, thereby improving the heat exchange efficiency.

[0021] The serpentine heat exchanger may include unit serpentine tubes, each forming one of the plurality of rows.

[0022] Accordingly, by forming single rows using unit serpentine tubes of the same shape and flexibly increasing or decreasing the number of rows as needed, it is possible to improve the manufacturability and variability of the serpentine heat exchanger.

[0023] The unit serpentine tube may be configured such that a parallel portion extending in a first direction perpendicular to the flow direction of the second fluid, and a bent portion extending from an end of the parallel portion and bent in a direction perpendicular to the flow direction of the second fluid and the first direction are repeatedly formed.

[0024] Accordingly, by manufacturing the unit serpentine tube as a set of unit elements, the length of the unit serpentine tube may be flexibly increased or decreased as needed, thereby improving the manufacturability and variability of the serpentine heat exchanger.

[0025] The parallel portion and the bent portion may be coupled in a fitting manner. Accordingly, by enabling the parallel portion and the bent portion to be coupled in a fitting manner, it is possible to further improve the manufacturability and variability of the unit serpentine tube.

[0026] The fin may extend in a direction in which the plurality of rows formed by the serpentine tube are arranged to connect the plurality of rows to each other.

[0027] Accordingly, as the fin integrally connected to the plurality of rows is provided, the distance between the rows may be securely maintained, thereby preventing thermal deformation, which causes the serpentine tubes of different rows to adhere to each other due to thermal distortion.

[0028] The serpentine tube may be a flat tube of a microchannel heat exchanger, and the fin may be a fin in a form used in a microchannel heat exchanger.

[0029] Accordingly, by adopting the flat tube and the fin used in a microchannel heat exchanger, it is possible to combine the advantages of different types of heat exchangers into the serpentine heat exchanger.

[0030] Details of other embodiments are included in the detailed description and the accompanying drawings.[Advantageous Effects]

[0031] A serpentine heat exchanger according to the present disclosure has one or more of the following effects.

[0032] First, as a plurality of rows are provided, it is possible to provide a serpentine heat exchanger that facilitates scalable manufacturing and improves heat exchange efficiency.

[0033] Second, as a single header connecting a plurality of rows is provided, it is possible to provide a serpentine heat exchanger capable of greatly increasing the heat transfer area and reducing manufacturing costs.

[0034] Third, it is possible to provide a serpentine heat exchanger in which a flow path can be simply formed through an internal partition wall structure.

[0035] Fourth, by forming single (or individual) rows using unit serpentine tubes of the same shape and flexibly increasing or decreasing the number of rows as needed, it is possible to provide a serpentine heat exchanger with improved manufacturability and variability.

[0036] Fifth, it is possible to provide a serpentine heat exchanger in which a unit serpentine tube is fabricated as a set of unit elements to allow the length of the unit serpentine tube to be flexibly increased or decreased as needed, thereby further improving manufacturability and variability.

[0037] Sixth, as a fin integrally connected to a plurality of rows is provided, it is possible to provide a serpentine heat exchanger that is resistant to thermal deformation.

[0038] Seventh, by adopting flat tubes and fins employed in microchannel heat exchangers, it is possible to provide a serpentine heat exchanger with the advantages of different types of heat exchangers.

[0039] The effects of the present disclosure are not limited to the effects described above, and other effects not mentioned will be clearly understood by those skilled in the art from the claims.[Brief Description of Drawings]

[0040] FIG. 1 is a perspective view of a conventional serpentine heat exchanger. FIG. 2 is a perspective view of a conventional microchannel heat exchanger. FIG. 3 is a perspective view of a serpentine heat exchanger according to an embodiment of the present disclosure. FIG. 4 is a perspective view illustrating a unit serpentine tube of a serpentine heat exchanger according to an embodiment of the present disclosure. FIG. 5 is a transparent perspective view of a portion of FIG. 3. FIG. 6 is a front view of FIG. 3. FIG. 7 is a plan view of FIG. 3. FIG. 8 is a plan view of a serpentine heat exchanger according to another embodiment of the present disclosure. [Mode for the Invention]

[0041] The above and other aspects, features and other advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings. Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings; however, they may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the exemplary embodiments to those skilled in the art. The same reference numerals are used throughout the drawings to designate the same or similar components.

[0042] The terms herein are merely used to describe various embodiments of the present disclosure but are not intended to limit the present disclosure. Singular forms are intended to include plural forms unless the context clearly indicates otherwise. The terms "comprise" and / or "comprising" used in this specification do not exclude presence or addition of one or more other constituents, steps and / or operations in addition to the stated constituent, step, and / or operation.

[0043] In the drawings, the thickness or size of each component is exaggerated, omitted, or schematically illustrated for ease description and clarity. In addition, the size or area of each component does not completely reflect the real size or area thereof.

[0044] Hereinafter, fluid flowing inside the tube is referred to as a first fluid, and fluid flowing between fins (7) outside the tube is referred to as a second fluid. For example, the first fluid may be understood as a refrigerant having high heat conductivity. The second fluid may be, for example, air.

[0045] For convenience of explanation, the description will be based on the orientations shown in the drawings. For example, the second fluid may be described as flowing from the +z side to the -z side. For example, a plurality of rows of a serpentine tube (1) may be arranged along the z-axis. In addition, for the sake of convenience, the y-axis direction may be referred to as the up-down direction, the x-axis direction may be referred to as the left-right direction, and the z-axis direction may be referred to as the front-rear direction.

[0046] The serpentine heat exchanger herein may constitute a part of a heat pump. Since matters related to the heat pump are well known to those skilled in the art, a separate description thereof will be omitted, and the following description will focus on the serpentine heat exchanger.

[0047] Referring to FIG. 3, a serpentine heat exchanger of the present disclosure includes a serpentine tube 1, a fin 7, an inlet pipe 11, and an outlet pipe 12.

[0048] The serpentine tube 1 is bent multiple times to form a meandering flow path. The first fluid flows through the serpentine tube 1. The fin 7 is disposed between adjacent portions of the serpentine tube 1. The serpentine tube 1 and the fin 7 may be made of a material having high heat conductivity.

[0049] The serpentine tube 1 may be a flat tube typically employed in microchannel heat exchangers (MCHE). The fin 7 may be in the form of a fin typically employed in microchannel heat exchangers. Therefore, the advantages of different types of heat exchangers can be combined by adopting the flat tube and fin used in microchannel heat exchangers into the serpentine heat exchanger.

[0050] The inlet pipe 11 is connected to one end of the serpentine tube 1 so as to supply the first fluid to the serpentine tube 1. For example, the inlet pipe 11 may be a circular pipe having a predetermined diameter. The outlet pipe 12 is connected to another end of the serpentine tube 1 so as to discharge the first fluid from the serpentine tube 1. For example, the outlet pipe 12 may be a circular pipe having a predetermined diameter.

[0051] The serpentine tube 1 of the present disclosure forms a plurality of rows arranged in a flow direction of the second fluid that exchanges heat with the first fluid. A single row may provide a heat exchange area on a plane perpendicular to the flow direction (front-rear direction) of the second fluid. Each of the single rows arranged in the front-rear direction may have the same or similar configuration and shape.

[0052] Accordingly, by forming the serpentine heat exchanger composed of the serpentine tube 1 as a multi-row structure, it is possible to provide a serpentine heat exchanger that facilitates scalable manufacturing and improves heat exchange efficiency.

[0053] Each of the single rows arranged in the front-rear direction may be disposed such that positions of the tubes and the fins 7 are aligned in a line. When viewed from the front-rear direction, the shape of the plurality of rows may be described as being the same as the shape of a single row.

[0054] For example, the serpentine tube 1 may consist of a first row A, a second row B, and a third row C. In this case, the serpentine tubes 1 of the respective rows may be aligned in a line in the front-rear direction.

[0055] Referring to FIGS. 4 to 7, each of the plurality of rows of the serpentine tube 1 may be formed by a unit serpentine tube 2. The unit serpentine tube 2 may be understood as a modularized serpentine tube 1 defining a single row. For example, the serpentine tube 1 having three rows may be formed by a unit serpentine tube 2 for the first row A, a unit serpentine tube 2 for the second row B, and a unit serpentine tube 2 for the third row C.

[0056] Accordingly, by forming single rows using the respective unit serpentine tubes 2 of the same shape and flexibly increasing or decreasing the number of rows as needed, it is possible to improve the manufacturability and variability of the serpentine heat exchanger.

[0057] The unit serpentine tube 2 may include an inlet portion 3 and an outlet portion 4. The inlet portion 3 may be one end portion of the unit serpentine tube 2 into which the first fluid is introduced. The outlet portion 4 may be another end portion of the serpentine tube 1 from which the first fluid is discharged.

[0058] As the plurality of rows are aligned in a line in the front-rear direction, it is apparent that the inlet portion 3 and outlet portion 4 of the unit serpentine tubes 2, each forming a respective row, may also be aligned in a line in the front-rear direction. For example, according to the illustrated embodiment, an inlet portion 3a of the first row (the inlet portion 3 of the unit serpentine tube 2 forming the first row A, which is hereinafter simply referred to as the 'inlet portion 3a of the first row', and the same applies to the following), an outlet portion 4b of the second row, and an inlet portion 3c of the third row may be aligned in a line in the front-rear direction, and an outlet portion 4a of the first row, an inlet portion 3b of the second row, and an outlet portion 4c of the third row may be aligned in a line in the front-rear direction.

[0059] The unit serpentine tube 2 may be formed of a parallel portion 5 and a bent portion 6. The parallel portion 5 and the bent portion 6 may be understood as smaller modular manufacturing units that make up the unit serpentine tube 2.

[0060] The parallel portion 5 may extend in a first direction perpendicular to the flow direction of the second fluid. The first direction may be understood as the x-axis direction (left-right direction) when viewed in the illustrated orientation. The bent portion 6 may extend from an end of the parallel portion 5 and be bent in a direction perpendicular to the flow direction of the second fluid and the first direction. The direction perpendicular to the flow direction of the second fluid and the first direction may be understood as the y-axis direction (up-down direction) when viewed in the illustrated orientation.

[0061] The parallel portion 5 and the bent portion 6 may be repeatedly formed. For example, the unit serpentine tube 2 may be understood as having a form (or structure) in which 'a long tube in the shape of a flat plate is extended in the right direction (+x) by a predetermined distance (the length of the parallel portion 5 in the left-right direction) to form a parallel portion 5, an end of the parallel portion 5 is bent 180 degrees downward (-y) to form a bent portion 6, and from an end of the bent portion 6, the tube is again extended in the left direction (-x) by the predetermined distance to form another parallel portion 5, an end of the parallel portion 5 is bent 180 degrees downward (-y) again to form another bent portion 6..., and so on'.

[0062] Accordingly, by fabricating the unit serpentine tube 2 as a set of unit elements, the length of the unit serpentine tube 2 may be flexibly increased or decreased as needed, thereby improving the manufacturability and variability of the serpentine heat exchanger.

[0063] Meanwhile, unlike the method of manufacturing the unit serpentine tube 2 by bending a long flat tube, it is also evident that a method in which the parallel portions 5 and the bent portions 6 are separately manufactured and then assembled may be adopted. In this case, the parallel portions 5 and the bent portions 6 may be coupled in a fitting manner, which can further improve the variability of the unit serpentine tube 2.

[0064] Meanwhile, a plurality of unit serpentine tubes 2 may be connected via a connecting part 9. The connecting part 9 may connect the inlet portion 3 and the outlet portion 4 of the unit serpentine tubes 2 arranged in adjacent rows. The first fluid introduced into the inlet portion 3 of any one of the unit serpentine tubes 2 may be discharged through the outlet portion 4 of the corresponding unit serpentine tube 2. The first fluid discharged through the outlet portion 4 of the corresponding unit serpentine tube 2 may then be introduced into the inlet portion 3 of another unit serpentine tube 2 adjacent thereto via the connecting part 9.

[0065] For example, the connecting part 9 may be configured as a header. In this case, all of the inlet portions 3 or outlet portions 4 on the same line in the front-rear direction may be connected by a single header. In addition, since the inlet portion 3 and the outlet portion 4 of each of the unit serpentine tubes 2 are aligned in a line in the front-rear direction, only two headers may be required for the entire serpentine heat exchanger. In this case, the headers may be referred to as an inlet header 9a and an outlet header 9b, respectively.

[0066] For example, according to the illustrated embodiment, each of the inlet portion 3a of the first row, the outlet portion 4b of the second row, and the inlet portion 3c of the third row may be connected to the inlet header 9a, and the inlet pipe 11 may be connected to the inlet header 9a. For example, each of the outlet portion 4a of the first row, the inlet portion 3b of the second row, and the outlet portion 4c of the third row may be connected to the outlet header 9b, and the outlet pipe 12 may be connected to the outlet header 9b.

[0067] That is, the inlet pipe 11 may be in communication with the inlet header 9a. The outlet pipe 12 may be in communication with the outlet header 9b. In addition, each of the inlet header 9a and the outlet header 9b may be formed as a single header. The inlet header 9a and the outlet header 9b may extend in the flow direction of the second fluid.

[0068] Accordingly, by connecting multiple rows using a single header, it is possible to significantly increase the heat transfer area and reduce manufacturing costs, compared to a conventional configuration in which a plurality of headers are respectively connected to individual rows in the multiple rows.

[0069] Meanwhile, the inlet portion 3 and the outlet portion 4 of the unit serpentine tube 2 may be respectively coupled to the inlet header 9a and the outlet header 9b in a fitting manner. The header may be provided with a hole into which the outlet portion 4 or the inlet portion 3 is inserted. A separate rubber member may be provided to prevent a gap from occurring due to a clearance when the outlet portion 4 and the inlet portion 3 are inserted into the header. Accordingly, it is possible to improve the manufacturing convenience of the serpentine heat exchanger composed of the unit serpentine tube 2 and the header.

[0070] Meanwhile, the rows formed by the serpentine tube 1 may include at least three rows. In this case, each of the inlet header 9a and the outlet header 9b may include therein a partition wall 10 to separate the rows.

[0071] When the serpentine tube 1 is constructed with three or more rows and a single header is used, it may be necessary to additionally provide the partition wall 10 in order to define the flow path. For example, according to the illustrated embodiment, in order to ensure that the first fluid introduced into the inlet header 9a through the inlet pipe 11 does not bypass the first row A but instead flows into the inlet portion 3 of the first row and is discharged through the outlet portion 4a of the first row, the partition wall 10 may be disposed between the inlet portion 3a of the first row and the outlet portion 4b of the second row within the inlet header 9a. For example, according to the illustrated embodiment, in order to prevent the first fluid discharged through the outlet portion 4a of the first row from bypassing the second row B and the third row C and flowing directly into the outlet pipe 12, the partition wall 10 may be disposed between the inlet portion 3b of the second row and the outlet portion 4c of the third row within the outlet header 9b.

[0072] Accordingly, by employing the internal partition wall (10) structure, the flow path through multiple rows can be simply formed using only a single header.

[0073] Meanwhile, the technical idea of the present disclosure is not limited to cases where the connecting part 9 is necessarily a header, and the connecting part 9 may be configured as a U-shaped pipe (not shown), for example.

[0074] The inlet pipe 11 may be connected to, among the plurality of rows, a rear row with respect to the flow direction of the second fluid. For example, the inlet pipe 11 may be connected to the first row A.

[0075] The outlet pipe 12 may be connected to, among the plurality of rows, a front row with respect to the flow direction of the second fluid. For example, the outlet pipe 12 may be connected to the third row C.

[0076] Accordingly, by allowing the first fluid to flow from the rear row to the front row, a counterflow relationship may be established between the second fluid and the first fluid, thereby improving heat exchange efficiency.

[0077] In addition, the inlet pipe 11 and the outlet pipe 12 may be connected to the same side of the serpentine heat exchanger (the illustrated embodiment). Alternatively, the inlet pipe 11 and the outlet pipe 12 may be disposed on opposite sides of the serpentine heat exchanger or may be disposed on other sides.

[0078] The fin 7 may be provided as an integrated fin 8 that extends in a direction in which the plurality of rows formed by the serpentine tube 1 are arranged to connect the plurality of rows (see FIG. 8). For example, according to the embodiment illustrated in FIG. 8, the fin 8 extending in the front-rear direction and integrally connected to the first row A to the third row C may be provided.

[0079] Accordingly, by providing the fin 8 integrally connected to the plurality of rows, the distance between the rows may be securely maintained, thereby preventing thermal deformation, which causes the serpentine tubes 1 of different rows to adhere to each other due to thermal distortion.

[0080] It will be apparent that, although the preferred embodiments have been shown and described above, the present disclosure is not limited to the above-described specific embodiments, and various modifications and variations can be made by those skilled in the art without departing from the scope of the appended claims. Therefore, it is intended that the modifications and variations should not be understood independently of the technical spirit or prospect of the present disclosure.

Claims

1. A serpentine heat exchanger comprising: a serpentine tube in which a first fluid flows and bent multiple times to define a meandering flow path; a fin disposed between adjacent portions of the serpentine tube; an inlet pipe connected to one end of the serpentine tube so as to supply the first fluid to the serpentine tube; and an outlet pipe connected to another end of the serpentine tube so as to discharge the first fluid from the serpentine tube, wherein the serpentine tube forms a plurality of rows arranged in a flow direction of a second fluid that exchanges heat with the first fluid.

2. The serpentine heat exchanger of claim 1, wherein each of the plurality of rows formed by the serpentine tube comprises: an inlet portion that defines one end portion of the serpentine tube into which the first fluid is introduced; and an outlet portion that defines another end portion of the serpentine tube from which the first fluid is discharged, and wherein the serpentine heat exchanger further comprises a connecting part to connect the inlet portion and the outlet portion of adjacent rows.

3. The serpentine heat exchanger of claim 2, wherein the connecting part comprises: an inlet header in communication with the inlet pipe; and an outlet header in communication with the outlet pipe.

4. The serpentine heat exchanger of claim 3, wherein the inlet header and the outlet header are each configured as a single header.

5. The serpentine heat exchanger of claim 4, wherein the inlet portion and the outlet portion of the serpentine tube are coupled to the inlet header and the outlet header in a fitting manner.

6. The serpentine heat exchanger of claim 3, wherein the plurality of rows are at least three rows, and wherein the inlet header and the outlet header each include therein a partition wall to separate the rows.

7. The serpentine heat exchanger of claim 3, wherein the inlet header and the outlet header extend in the flow direction of the second fluid.

8. The serpentine heat exchanger of claim 2, wherein the connecting part is a U-shaped pipe.

9. The serpentine heat exchanger of claim 1, wherein: the inlet pipe is connected to, among the plurality of rows, a rear row with respect to the flow direction of the second fluid; and the outlet pipe is connected to, among the plurality of rows, a front row with respect to the flow direction of the second fluid.

10. The serpentine heat exchanger of claim 1, comprising unit serpentine tubes, each forming one of the plurality of rows.

11. The serpentine heat exchanger of claim 10, wherein the unit serpentine tube is configured such that a parallel portion extending in a first direction perpendicular to the flow direction of the second fluid and a bent portion extending from an end of the parallel portion and bent in a direction perpendicular to the flow direction of the second fluid and the first direction are repeatedly formed.

12. The serpentine heat exchanger of claim 11, wherein the parallel portion and the bent portion are configured to be coupled in a fitting manner.

13. The serpentine heat exchanger of claim 1, wherein the fin extends in a direction in which the plurality of rows formed by the serpentine tube are arranged to connect the plurality of rows to each other.

14. The serpentine heat exchanger of claim 1, wherein: the serpentine tube is a flat tube of a microchannel heat exchanger; and the fin is a fin in a form used in a microchannel heat exchanger.

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