CN223179357U

CN223179357U - Heat exchangers and heat exchange systems

Info

Publication number: CN223179357U
Application number: CN202422437661.2U
Authority: CN
Inventors: 丁二刚; 孙雨
Original assignee: Zhejiang Dunan Thermal Technology Co Ltd
Current assignee: Zhejiang Dunan Thermal Technology Co Ltd
Priority date: 2024-10-09
Filing date: 2024-10-09
Publication date: 2025-08-01
Anticipated expiration: 2034-10-09

Abstract

The present application relates to a heat exchanger and a heat exchange system, wherein the heat exchanger includes two heat exchange units, each of which includes a plurality of heat exchange flat tubes arranged at intervals and a header connected to the plurality of heat exchange flat tubes. The heat exchange flat tubes in the two heat exchange units are arranged alternately. The heat exchange flat tubes have a flow channel that folds back along their length, with the inlet and outlet of the flow channel located at the same end. There are two headers in each heat exchange unit, the two headers correspondingly connecting the inlet and outlet, and the headers of the two heat exchange units are located on opposite sides of the heat exchanger. The heat exchanger of the present application has a more regular and compact appearance, and each header adopts a multi-section split docking method, which is more convenient for processing and assembly and can flexibly adapt to different design requirements.

Description

Heat exchanger and heat exchange system

Technical Field

The application relates to the technical field of heat exchange equipment, in particular to a heat exchanger and a heat exchange system.

Background

Dual system, variable load and multiple medium heat dissipation will be one of the directions and ideas for the energy efficiency improvement of refrigeration systems. The evaporator in the double-loop refrigerating system has application in various fields of household, commercial and industrial cooling.

The three-medium microchannel heat exchanger in the prior art comprises two heat exchange units, each heat exchange unit comprises a plurality of flat pipes and two collecting pipes, the flat pipes are arranged in a single flow way, two ends of each flat pipe are respectively communicated with the collecting pipes, the flat pipes of the two heat exchange units are arranged in a staggered mode along the length direction of each collecting pipe, the flat pipe of one heat exchange unit needs to be bent to avoid the collecting pipe of the other heat exchange unit, but the bending processing difficulty of the flat pipe is increased, the processing of the heat exchanger is not facilitated, and the overall structure compactness of the heat exchanger is poor.

Disclosure of utility model

The application provides the heat exchanger which is convenient to assemble and process and can further improve the compactness of the whole structure of the heat exchanger, and the heat exchanger can be suitable for a multi-medium heat exchange scene.

The application relates to a heat exchanger, which comprises two heat exchange units, wherein each heat exchange unit comprises a plurality of heat exchange flat pipes which are arranged at intervals, and a collecting pipe communicated with the plurality of heat exchange flat pipes, and the heat exchange flat pipes in the two heat exchange units are alternately arranged;

The flat heat exchange tube is provided with a flow passage which is folded back along the length direction of the flat heat exchange tube, an inlet and an outlet of the flow passage are positioned at the same end part, two collecting pipes in the same heat exchange unit are correspondingly communicated with the inlet and the outlet, and the collecting pipes of the two heat exchange units are positioned at two opposite sides of the heat exchanger.

The following provides several alternatives, but not as additional limitations to the above-described overall scheme, and only further additions or preferences, each of which may be individually combined for the above-described overall scheme, or may be combined among multiple alternatives, without technical or logical contradictions.

In one embodiment, the collecting pipe comprises a plurality of unit pipes which are sequentially communicated, and each heat exchange flat pipe in the same heat exchange unit is communicated with the corresponding unit pipe.

In one embodiment, the longest distance of the two collecting pipes in the same heat exchange unit along the width direction of the heat exchange flat pipe is L, and the widths of the heat exchange flat pipe are L, and L meet the condition that L is greater than L.

In one embodiment, the central lines of the two collecting pipes (200) in the same heat exchange unit are staggered in the length direction of the heat exchange flat pipe (100), and the relationship between L and L is satisfied:

In one embodiment, each collecting pipe is provided with a joint pipe, all the joint pipes in the heat exchanger are positioned on the same side of the heat exchanger, and the corresponding joint pipes in the two heat exchange units are bent towards each other.

In one embodiment, in two joint pipes in the same heat exchange unit, the pipe diameter of one joint pipe is OD1, the pipe diameter of the other joint pipe is OD2, and the conditions that OD1 is less than or equal to OD2 and less than or equal to 1.56 times OD1 are satisfied.

In one embodiment, adjacent heat exchange flat tubes are thermally coupled through fins, one side of the heat exchanger is a windward side positioned at the upstream of air flow along the width direction of the heat exchange flat tubes, the two heat exchange units are respectively independently used as an evaporator or a condenser, and the inlet side is at the windward side.

In one embodiment, among the plurality of unit pipes, two adjacent unit pipes are directly in plug-in fit, or an intermediate pipe is arranged between the two adjacent unit pipes and is communicated with each other through the intermediate pipe.

In one embodiment, one of the adjacent unit pipes and the intermediate pipe is provided with a diameter-reducing part, and the other unit pipe and the intermediate pipe are in plug-in fit through the diameter-reducing part.

In one embodiment, the length of the unit pipe is L1 along the length direction of the collecting pipe, the length of the intermediate pipe is L2, and l1:l2=1 (0.5-2) is satisfied.

The application also provides a heat exchange system, which comprises the heat exchanger, wherein two heat exchange units are respectively connected with corresponding heat exchange media, and each heat exchange unit independently adopts a refrigerant or water as the heat exchange media.

The heat exchanger provided by the application has the advantages that the flat pipes do not need to be bent, the communication between the flat pipes corresponding to the two heat exchange units and the collecting pipes can be realized, the assembly and the processing are convenient, the compactness of the whole structure of the heat exchanger is improved, the collecting pipes adopt a multi-section split butt joint mode, the processing and the assembly are more convenient, and the heat exchanger can flexibly adapt to different design requirements.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments or the conventional techniques of the present application, the drawings required for the descriptions of the embodiments or the conventional techniques will be briefly described below, and it is apparent that the drawings in the following descriptions are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.

FIG. 1 is a schematic view of a heat exchanger according to an embodiment of the present application;

FIG. 2 is a schematic view of the heat exchanger of FIG. 1 with fins omitted;

FIG. 3 is an enlarged view of portion A of FIG. 2;

FIG. 4 is a schematic diagram of the pipe diameters of the joint pipes of the heat exchanger according to an embodiment of the present application;

FIG. 5 is a schematic diagram illustrating a spacing between heat exchanging flat tubes of a heat exchanger according to an embodiment of the present application;

FIG. 6 is a schematic diagram illustrating the fit between a plurality of unit pipes according to an embodiment of the present application;

FIG. 7 is an enlarged schematic view of the cell tube and intermediate tube of FIG. 6;

FIG. 8 is a schematic diagram of a heat exchange system according to an embodiment of the present application;

fig. 9 is a schematic diagram of a heat exchange system according to another embodiment of the present application.

The reference numerals of the elements are as follows:

100. Heat exchange flat tube, 100a, first heat exchange flat tube, 100b, second heat exchange flat tube, 200, collecting pipe, 210, inflow tube, 210a, first inflow tube, 210b, second inflow tube, 220, outflow tube, 220a, first outflow tube, 220b, second outflow tube, 230, joint tube, 230a, first joint tube, 230b, second joint tube, 230c, third joint tube, 230d, fourth joint tube, 240, unit tube, 241, slot, 242, first diameter reduction part, 250, intermediate tube, 251, second diameter reduction part, 300, fin.

Detailed Description

In order that the above objects, features and advantages of the application will be readily understood, a more particular description of the application will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. The present application may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the application, whereby the application is not limited to the specific embodiments disclosed below.

It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When a component is considered to be "connected" to another component, it can be directly connected to the other component or intervening components may also be present. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and the like are used in the description of the present application for the purpose of illustration only and do not represent the only embodiment.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present application, unless expressly stated or limited otherwise, a first feature "up" or "down" on a second feature may be that the first feature is in direct contact with the second feature, or that the first feature and the second feature are in indirect contact through intermedial media. Moreover, a first feature "above," "over" and "on" a second feature may be a first feature directly above or obliquely above the second feature, or merely indicate that the first feature is higher in level (or in a state of use, or in view of some drawing) than the second feature. A first feature "under", "beneath" and "under" a second feature may be a first feature directly under or obliquely below the second feature, or merely indicate that the first feature is less level than the second feature (or in a state of use, or at some viewing angle of the drawing).

Unless defined otherwise, all technical and scientific terms used in the specification of the present application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and/or" as used in the description of the present application includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1-3, an embodiment of the present application provides a heat exchanger, including two heat exchange units, where the two heat exchange units are independent and serve as evaporators or condensers, and may form a dual-flow system, for example, two heat exchange units may be introduced with different refrigerants, one side may be used as an evaporator and one side may be used as a heat medium, for example, two heat exchange units may be introduced with the same refrigerant, and two heat exchange units may be introduced with the same refrigerant, for example, two heat exchange units may be introduced with the same refrigerant.

Each heat exchange unit comprises a plurality of heat exchange flat pipes 100 which are arranged at intervals and a collecting pipe 200 which is communicated with the plurality of heat exchange flat pipes 100, and the heat exchange flat pipes 100 in the two heat exchange units are alternately arranged. The heat exchange flat tube 100 itself may be combined with the prior art, for example, the heat exchange flat tube 100 is plate-shaped as a whole and has opposite length directions L and width directions W.

The flat heat exchange tube 100 may include a first plate body and a second plate body fastened and fixed to each other, where the two plate bodies enclose a fluid channel of a heat exchange medium, for example, the first plate body includes a first body and a first protrusion, the first protrusion is arranged on the first body in a protruding manner and forms a fluid channel with the second body, for example, the second plate body includes a second body and a second protrusion, the second protrusion is arranged on the second body in a protruding manner and forms a fluid channel with the first body, for example, the first plate body has a first protrusion, the second plate body has a second protrusion, and the first protrusion and the second protrusion form a fluid channel. The heat exchange flat tube 100 with the structural characteristics can be applied to a micro-plate heat exchanger, the adjacent heat exchange flat tubes 100 can be thermally coupled through the fins 300, and the heat exchanger of the embodiment can be used for three-medium heat exchange by combining the air flow passing through the fins 300.

The heat exchange flat tube 100 is provided with a flow passage which is folded back along the length direction of the heat exchange flat tube 100, the inlet and the outlet of the flow passage are positioned at the same end part, two collecting pipes 200 in the same heat exchange unit are arranged at the same side of the length direction of the heat exchange flat tube 100, the two collecting pipes 200 are correspondingly communicated with the inlet and the outlet, and the collecting pipes 200 of the two heat exchange units are positioned at two opposite sides of the heat exchanger.

The reasonable arrangement mode of the collecting pipes 200 can further reduce the space interference of the collecting pipes and improve the compactness of the whole structure of the heat exchanger. In this embodiment, the header 200 adopts a split butt joint manner, and the header 200 includes a plurality of unit pipes 240 that are sequentially connected in an extending direction of the header 200, and slots 241 are formed on sidewalls of the unit pipes 240, and each heat exchange flat pipe 100 in the same heat exchange unit is connected to a corresponding unit pipe 240 through the slots 241.

One of the two collecting pipes 200 in the same heat exchange unit is used as an inflow pipe 210, the other is used as an outflow pipe 220, one side of the heat exchange flat pipe 100 in the length direction is provided with an inlet and an outlet (the dotted arrow in fig. 3 indicates the direction that a heat exchange medium passes through the fluid channel through the inlet and the outlet), and the inlet and the outlet are arranged on the same side, so that the flow path in the heat exchange flat pipe 100 can be increased, and the heat exchange efficiency can be improved. The heat exchange flat tube 100 is respectively converged in the shape of the inlet and the outlet to form a plugging portion, and the plugging portion is in sealed plugging with the slot 241 in the corresponding unit tube 240, for example, the plugging portion can be fixed by adopting a brazing mode or the like.

The collecting pipe 200 of the embodiment comprises a plurality of sections of unit pipes 240, and the length of the unit pipes 240 can be flexibly adjusted according to the interval between the flat heat exchange pipes 100. The inlet and the outlet of the heat exchange flat tube 100 are arranged on the same side, and the inflow tube 210 and the outflow tube 220 on the side are arranged side by side, so that the overall structure is more compact, and the heat exchange efficiency is improved.

The two collecting pipes 200 in the same heat exchange unit are arranged in the width direction of the heat exchange flat pipe 100 in such a way that the centers of the two collecting pipes 200 are aligned with each other, or the centers of the two collecting pipes 200 are staggered and arranged in a manner that the sides facing the heat exchange flat pipe 100 are aligned with each other. In any way, in order to further optimize the layout, the two collecting pipes 200 have a first side edge and a second side edge which are far away from each other, and the first side edge and the second side edge do not exceed the width boundary of the flat heat exchange tube 100, for example, the longest distance of the two collecting pipes 200 in the same heat exchange unit along the width direction of the flat heat exchange tube 100 is L, and the widths of the flat heat exchange tube 100 are L, and L satisfy that L > L, which makes the whole structure of the heat exchanger compact, the appearance more regular, the storage and transportation stacking convenient, and the matching with peripheral equipment in the use environment.

In some preferred embodiments, the centerlines of two headers 200 in the same heat exchange unit are staggered in the length direction of the flat heat exchange tube 100, and the relationship between L and L is:

In the staggered arrangement mode of the centers of the two collecting pipes 200, as the pipe diameters of the two collecting pipes 200 are different, the centers of the two collecting pipes 200 can be staggered in the length direction of the heat exchange flat pipe 100, and the two collecting pipes can be further close to each other in the width direction of the heat exchange flat pipe 100 according to the space size requirement, so that the overall structure of the heat exchanger is more compact, and meanwhile, the two collecting pipes 200 are convenient to install.

For heat exchangers of different specifications, L and L above may be set in equal proportion, for example, when the tube diameter of each header 200 is reduced, the width of the heat exchange flat tube 100 is reduced synchronously. The sum of the pipe diameters of the two collecting pipes 200 is generally smaller than the width of the heat exchange flat pipe 100, so that the two collecting pipes 200 can not protrude outside the heat exchange flat pipe 100 in the width direction of the heat exchange flat pipe 100.

In order to facilitate connection of external pipes and devices to form a heat exchange system, each header 200 is provided with a joint pipe 230, all the joint pipes 230 in the heat exchanger are located on the same side of the heat exchanger, and as for the whole heat exchanger, the number of the joint pipes 230 is four, and the corresponding joint pipes 230 in two heat exchange units are bent towards each other. The arrangement can prevent the joint pipe 230 from protruding outside the collecting pipe 200 in the length direction of the flat heat exchange pipe 100, so that the joint pipe 230 is convenient to pre-assemble, the whole appearance is still kept regular, and the occupied space is reduced.

When the heat exchanger of the embodiment is used as a three-medium heat exchanger, besides the corresponding configuration of the two heat exchange units, the heat exchanger can also be combined with the airflow direction of the fin 300, for example, along the width direction of the heat exchange flat tube 100, wherein one side of the heat exchanger is the windward side positioned at the upstream of the airflow, and the airflow flows from the windward side to the other side of the fin 300.

In the heat exchange unit used as the evaporator, the pipe diameter of the inflow pipe 210 is smaller than that of the outflow pipe 220, that is, the pipe diameter of the inflow pipe 210 is smaller, because the medium flowing inside the inflow pipe 210 side has smaller specific volume than the outflow pipe 220 side as the evaporator function.

In the heat exchange unit used as the condenser, the pipe diameter of the inflow pipe 210 is larger than that of the outflow pipe 220, that is, the pipe diameter of the inflow pipe 210 is larger, because the medium flowing inside the side of the inflow pipe 210 is larger than that of the outflow pipe 220 as the condenser functions.

Referring to fig. 4, in one embodiment, the size configuration of header 200 and header 230 is further optimized, for example:

In order to adapt to the specific volume change of the refrigerant and balance heat exchange and pressure drop, when the heat exchange unit is used as a condenser, D2 is larger than D1, and similarly, if the heat exchange unit is used as an evaporator, the relationship between the pipe diameters is reverse, the pipe diameter can be understood as an inner diameter, and the pipe diameter can be understood as an outer diameter on the premise that the pipe walls are the same or basically the same.

The other heat exchange unit is provided with a second inflow pipe 210b with a pipe diameter of D3 and a second outflow pipe 220b with a pipe diameter of D4, and when the heat exchange unit is used as an evaporator, D4 is larger than D3, and similarly, the relationship between the pipe diameters is reverse when the heat exchange unit is used as a condenser.

In fig. 4, the corresponding connection relationship between the collecting pipe and the joint pipe is that the first outlet pipe 220a is communicated with the first joint pipe 230a, the pipe diameter is OD1, the first inlet pipe 210a is communicated with the second joint pipe 230b, the pipe diameter is OD2, the second inlet pipe 210b is communicated with the third joint pipe 230c, the pipe diameter is OD3, the second outlet pipe 220b is communicated with the fourth joint pipe 230d, the pipe diameter is OD4, and the requirements that OD1< OD2 is less than or equal to 1.56 x OD1, the diameter of OD1 is relatively small, the uniform liquid separation of the heat exchange medium is facilitated, OD1< OD2 is suitable for the specific volume change and balance heat exchange and pressure drop of the heat exchange medium, OD2 is not suitable for overlarge, otherwise, the outflow of the heat exchange medium is not facilitated. OD3< OD4 +.1.56 OD3.

In addition, when the evaporator is used, the pipe diameters of the second inflow pipe 210b and the third joint pipe 230c are not easy to be too large, so that the uniformity of liquid separation is ensured.

Referring to fig. 5, one heat exchange unit has a first heat exchange flat tube 100a with a thickness of M1, and the other heat exchange unit has a second heat exchange flat tube 100b with a thickness of M2, and the heat exchange amounts of the heat exchange units may have different design requirements, and the thicknesses of the heat exchange flat tubes may be adjusted accordingly, that is, the thicknesses of M1 and M2 may be equal or unequal. Similarly, the distance between two adjacent first heat exchange flat tubes 100a in one heat exchange unit is N1, and the distance between two adjacent second heat exchange flat tubes 100b in the other heat exchange unit is N2, and N1 and N2 can be equal or unequal.

Regarding the header 200, an integral or split-type butt joint manner may be adopted, in which two adjacent unit pipes 240 are directly inserted and engaged, and in a preferred embodiment, as shown in fig. 6 and 7, an intermediate pipe 250 is provided between the two adjacent unit pipes 240 and is communicated with each other through the intermediate pipe 250.

One of the adjacent unit pipes 240 and the intermediate pipe 250 has a reduced diameter portion, and is inserted into the other through the reduced diameter portion. For example, one end of the unit pipe 240 has a first reduced diameter portion 242, and is inserted into the intermediate pipe 250 adjacent to the side through the first reduced diameter portion 242, and similarly, one end of the intermediate pipe 250 has a second reduced diameter portion 251, and is inserted into the unit pipe 240 adjacent to the side through the second reduced diameter portion 251, and the locking portion may be smoothly or stepwise.

In this embodiment, the intermediate pipe 250 is used as a transition, so that not only can the thickness and the interval variation of the heat exchange flat pipe be flexibly adjusted and adapted, but also the error accumulation of processing and assembly can be avoided, the deformation and the internal stress in the later welding process are reduced, and the tightness is further ensured.

In one embodiment, the axial length between the unit pipe 240 and the intermediate pipe 250 is further optimized, for example, the length of the unit pipe 240 is L1 along the length direction of the header 200, and the length of the intermediate pipe 250 is L2, and l1:l2=1 (0.5-2), for example, l1:l2=1:1.

In other embodiments of the present application, a heat exchange system is further provided, including the heat exchangers of the foregoing embodiments, where two heat exchange units in the heat exchanger are respectively connected to corresponding heat exchange media, and each heat exchange unit independently uses a refrigerant or water as the heat exchange media. One of the two heat exchange units is connected to the first heat exchange system, the other one is connected to the second heat exchange system, and each heat exchange system can be provided with a compressor or not.

Referring to fig. 8, in one embodiment, heat exchanger a, heat exchanger B, and associated equipment such as compressors, throttles, ball valves, etc. are provided. Two sets of heat exchange systems are integrally formed, wherein the first heat exchange system is provided with a compressor and adopts a refrigerant as a heat exchange medium, the second heat exchange system is not provided with the compressor and adopts water as the heat exchange medium, and the mode can be applied to the fields of industrial laser water coolers and the like.

For heat exchanger A, one heat exchange unit is used for passing the high-temperature medium (as a condenser function) of the first heat exchange system, and the other heat exchange unit is used for passing the low-temperature medium (as an evaporator function) of the second heat exchange system, and the two heat exchange media and the air flowing through the fins exchange heat with each other.

For heat exchanger B, one of the heat exchange units takes away the low temperature medium of the first heat exchange system (functioning as an evaporator) and the other takes away the high temperature medium of the second heat exchange system (functioning as a condenser), the two heat exchange media and the air flowing through the fins exchanging heat with each other.

Referring to fig. 9, in another embodiment, the main difference from the embodiment of fig. 8 is that in the second heat exchange system, low-temperature water inlet and low-temperature water outlet are additionally provided for the heat exchanger B, so that the heat exchange effect is further enhanced.

The heat exchanger of the application is further optimally designed, improves the structural regularity, improves the assembly efficiency and flexibly adapts to different requirements.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description. When technical features of different embodiments are embodied in the same drawing, the drawing can be regarded as a combination of the embodiments concerned also being disclosed at the same time.

The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the claims. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of the application should be determined from the following claims.

Claims

1. A heat exchanger, characterized in that it comprises two heat exchange units, each of the heat exchange units comprising a plurality of heat exchange flat tubes (100) arranged at intervals, and a header (200) communicating with the plurality of heat exchange flat tubes (100), wherein the heat exchange flat tubes (100) in the two heat exchange units are arranged alternately;

The heat exchange flat tube (100) has a flow channel that is bent along its own length direction, and the inlet and outlet of the flow channel are located at the same end. There are two collecting pipes (200) in the same heat exchange unit, and the two collecting pipes (200) are correspondingly connected to the inlet and the outlet, and the collecting pipes (200) of the two heat exchange units are located on two opposite sides of the heat exchanger.

2. The heat exchanger according to claim 1 is characterized in that the collecting pipe (200) includes a plurality of unit tubes (240) connected in sequence, and each of the heat exchange flat tubes (100) in the same heat exchange unit is connected to the corresponding unit tube (240).

3. The heat exchanger according to claim 1, characterized in that the longest distance between the two collecting pipes (200) in the same heat exchange unit along the width direction of the heat exchange flat tube (100) is l, the width of the heat exchange flat tube (100) is L, and L and l satisfy: L>l.

4. The heat exchanger according to claim 3, characterized in that the center lines of the two headers (200) in the same heat exchange unit are staggered in the length direction of the heat exchange flat tube (100), and the relationship between L and l satisfies:

5. The heat exchanger according to claim 1 is characterized in that each of the collecting pipes (200) is provided with a joint pipe (230), and all the joint pipes (230) in the heat exchanger are located on the same side of the heat exchanger; and the corresponding joint pipes (230) in the two heat exchange units are bent toward each other.

6. The heat exchanger according to claim 5, characterized in that, among the two joint pipes (230) in the same heat exchange unit, the diameter of one of the joint pipes (230) is OD1, and the diameter of the other joint pipe (230) is OD2; and the following conditions are satisfied: OD1<OD2≤1.56*OD1.

7. The heat exchanger according to any one of claims 1 to 6, characterized in that adjacent heat exchange flat tubes (100) are thermally coupled via fins (300), and along the width direction of the heat exchange flat tubes (100), one side of the heat exchanger is on the windward side upstream of the airflow; the two heat exchange units each independently serve as an evaporator or a condenser, and the inlet side is on the windward side.

8. The heat exchanger according to claim 2 is characterized in that, among the plurality of unit tubes (240), two adjacent unit tubes (240) are directly plugged together, or an intermediate tube (250) is provided between two adjacent unit tubes (240), and the two adjacent unit tubes (240) are connected to each other through the intermediate tube (250).

9. The heat exchanger according to claim 8, characterized in that, along the length direction of the collecting pipe (200), the length of the unit tube (240) is L1; the length of the intermediate tube (250) is L2, and L1:L2=1:(0.5~2) is satisfied.

10. A heat exchange system, characterized in that it comprises the heat exchanger according to any one of claims 1 to 9, wherein the two heat exchange units are respectively connected to corresponding heat exchange media; and each heat exchange unit independently uses refrigerant or water as the heat exchange medium.