A tube for heat exchanger

Abstract

The object of the invention is, among others, a tube (10) for a heat exchanger (1), comprising: a first rectilinear section (11) and at least one second rectilinear section (12) each rectilinear section (11, 12) comprises two juxtaposed longer walls (13) having essentially flat surface connected by a pair of shorter walls (14) to form a closed profile of the tube (10), wherein the rectilinear sections (11, 12) are arranged at the same level, so that the respective longer walls (13) are coplanar with respect to each-other, wherein the tube (10) further comprises at least one bent section (15) arranged between the first rectilinear section (11) and the second rectilinear section (12), wherein the bent section (15) is arranged within the outline delimited by the longer walls (13) of neighboring rectilinear sections (11, 12). The another object of the invention is a heat exchanger (100) comprising such tube (10).

Description

FIELD OF THE INVENTION

[0001] The invention relates to a tube for a heat exchanger. In particular, the invention relates to the tube for heat exchanger for a motor vehicle.BACKGROUND OF THE INVENTION

[0002] To reduce the impact on climate change and under international pressure to reduce the CO 2 emissions for vehicle refrigerants used in mobile HVAC and refrigerant systems, the new refrigerant such as R744 (carbon dioxide or CO 2 ) has been introduced.

[0003] Thermodynamically, the R1234yf refrigerant has similar properties to R134a. However, its global warming potential or GWP is only 4, as opposed to 1430. The refrigerant R744 has been assigned a GWP value of 1 and functions as the reference gas.

[0004] Systems designed for use with R744 have pressures up to ten times higher than those intended for R1234yf. In summer, the peak pressure is around 100 bar, which is above the critical pressure level (supercritical process). This makes controlling the system more difficult, but not problematic. The coefficient of performance or COP is the same in moderate climate conditions, but slightly poorer in hot, moist climate zones. The system can be designed to compensate for this, as the components are smaller because of the higher volumetric cooling capacity of R744.

[0005] In comparison to R134a and R1234yf systems, the R744 refrigerant is at a disadvantage as R744 absorbs slightly less energy per unit of flow in a refrigerant cycle. In order to increase the performance level to that of R134a or R1234yf it is advised to use an Internal Heat exchanger (IHX).

[0006] An Internal Heat exchanger (IHX) is used to transfer heat between the low side pressure and the high pressure flow circuits. Its function is to improve system performance by further sub-cooling the refrigerant being supplied to, for example, an evaporator through the refrigerant control device.

[0007] Commonly used internal heat exchangers usually comprise, for example, a coaxial tube heat exchanger and a stacked heat exchanger.

[0008] The coaxial heat exchanger is usually designed as a "tube in tube" structure. Usually the outer tube is made of steel / copper, and the inner tube can be titanium, copper, copper-nickel depending on the requirements of working conditions. The coaxial heat exchanger usually conveys two fluids through separate circuits, wherein one circuit is conveyed in the opposite direction with respect to the other fluid.

[0009] The stacked plate heat exchanger design is usually suited to transferring heat between medium- and low-pressure fluids. Welded, semi-welded and brazed heat exchangers are used for heat exchange between high-pressure fluids or where a more compact product is required. In place of a pipe passing through a chamber, there are instead two alternating chambers, usually thin in depth, separated at their largest surface by a corrugated metal plate. The plates used in a plate and frame heat exchanger are obtained by one piece pressing of metal plates. Stainless steel is a commonly used metal for the plates because of its ability to withstand high temperatures, its strength, and its corrosion resistance.

[0010] Due to its structure, both coaxial and plate heat exchangers are not suitable for high-pressure R744 refrigerant. In spite of enhancing their structure and improving the sealing they are still prone to leakage when the high-pressure fluid is introduced. Further, the heat exchangers such as coaxial tube heat exchanger require its components to be large enough to efficiently transfer the heat between the media. Consequently, the heat exchangers described above are inconvenient in terms of packaging, costs of production and weight reduction.

[0011] It would be desired to produce a tube for internal heat exchanger that would sustain the pressure of high-pressure fluids, such as R744. The sub-components should preferably be made of inexpensive materials while maintaining high quality of the final product. Further, the production process of sub-components should be simple and efficient i.e. it would be desired to manufacture each sub-component using a method that does not require complicated production process.

[0012] Further, it would be desired to provide a tube heat exchanger which allows increased heat exchange surface in the heat exchanger to increase overall efficiency of the heat exchanger.

[0013] Finally, it would be desired to provide a tube for a heat exchange which shape could be adapted without changing one of the dimensions of said tube. This would allow provide a compact heat exchanger.SUMMARY OF THE INVENTION

[0014] The object of the invention is, among others A tube for a heat exchanger, comprising: a first rectilinear section and at least one second rectilinear section each rectilinear section comprises two juxtaposed longer walls having essentially flat surface connected by a pair of shorter walls to form a closed profile of the tube, wherein the rectilinear sections are arranged at the same level, so that the respective longer walls are coplanar with respect to each-other, wherein the tube further comprises at least one bent section arranged between the first rectilinear section and the second rectilinear section, wherein the bent section is arranged within the outline delimited by the longer walls of neighboring rectilinear sections.

[0015] Advantageously, the tube is configured for circulation of the fluid therein, wherein the rectilinear section is configured to provide a first intended fluid flow path, the second rectilinear section is configured to provide a second intended fluid flow path, wherein the bent section is configured to deflect the second intended fluid flow path with respect to the first intended fluid flow path, so that a direction and / or a sense of the second intended fluid flow path is different to the first intended fluid flow path.

[0016] Advantageously, the tube is a unitary element made in extrusion process, wherein said tube further comprises a plurality of micro-channels.

[0017] Advantageously, the bent section further comprises two juxtaposed flat sections having essentially flat surface, the flat sections being connected by a first deflection, and a second deflection, wherein the second deflection is different than the first deflection. Advantageously, the bent section is substantially U-shaped, so that the first intended fluid flow path is arranged in counter-flow with respect to the second intended fluid flow path.

[0018] Advantageously, the tube comprises two or more bent sections so that the tube has a meandering shape.

[0019] Advantageously, the first rectilinear section comprises a first length, the first length being measured in parallel with respect to axis of elongation of the first rectilinear section, the second rectilinear section comprises a second length, the second length being measured in parallel to axis of elongation of the second rectilinear section, wherein the first length is equal to the second length.

[0020] Advantageously, the first rectilinear section comprises a first length, the first length being measured in parallel with respect to axis of elongation of the first rectilinear section, the second rectilinear section comprises a second length, the second length being measured in parallel to axis of elongation of the second rectilinear section, wherein the first length is different than the second length.

[0021] Another object of the invention is a heat exchanger comprising a tube comprising at least one bent section.

[0022] Advantageously, the heat exchanger is configured to provide a heat exchange between a first fluid and at least a second fluid, the heat exchanger further comprising at least a first core comprising a plurality of tubes stacked together in a first stacking direction, wherein the heat exchanger further comprises: a first manifold comprising a first axis of elongation and a second manifold comprising a second axis of elongation being parallel to the first axis of elongation, wherein the core is configured to provide a fluidal communication between the first manifold and a second manifold.

[0023] Advantageously, the core comprises a first tube set configured for circulation of a first fluid, and at least a second tube set configured for circulation of a second fluid, wherein the tubes forming the first tube set are arranged alternately with the tubes forming the second tube set.

[0024] Advantageously, the first manifold comprises a first header configured to receive one end of the core, a first cover, and a first distribution plate sandwiched between the first cover and the first header, and wherein the second manifold comprises a second header configured to receive the other end of the core, a second cover, and a second distribution plate sandwiched between the second cover and the second header, wherein each of the first cover and the second cover comprises at least one channel fluidly connected with the first tube set and at least one second channel fluidly connected with the second tube set, wherein the channels are fluidly insulated from each other.

[0025] Advantageously, each of the headers comprises a slot, the slot being configured to receive the entire core.

[0026] Advantageously, the heat exchanger is internal heat exchanger.

[0027] The tube being subject- matter of the invention allows to keep small packaging thereof in at least one of the dimensions. Consequently, the entire heat exchanger is of small size.

[0028] The tube being subject- matter of the invention allows increased heat exchange surface in case two or more tubes are assembled together.

[0029] Last but not least, the tube allows to keep the same or greater heat exchange area compared to its straight counterpart, whereas the packaging of the tube is decreased.

[0030] The tube being subject- matter of the invention also allows providing a tube of desired shape without impeding flow therein.BRIEF DESCRITPTION OF DRAWINGS

[0031] Examples of the invention will be apparent from and described in detail with reference to the accompanying drawings, in which: Fig. 1 shows a perspective view of the tube having one bent section and a detailed section showing the cross-section of said tube. Fig. 2 shows a top view of tube of Fig.1 with intended fluid flow direction in straight section of said tube. Fig. 3 shows a top view of an exemplary tube comprising two bent sections. Fig. 4 shows a perspective view of the heat exchanger comprising tubes of figures 1 and 2. Fig. 5 shows a top view of the heat exchanger of Fig. 4. Fig. 6 shows a cross section of the manifold with plurality of tubes inserted into the header of said manifold. Fig. 7 shows a heat exchanger comprising tubes with two bent sections. DETAILED DESCRIPTION OF EMBODIMENTS

[0032] The subject-matter of an invention is a tube 10 for the heat exchanger 1 which is adapted for heat exchange between a first fluid and a second fluid. The first fluid may be, for example, pressurized refrigerant such as carbon-dioxide circulating within the heat exchanger 1 under first pressure, whereas the second fluid may be also the refrigerant such as carbon- dioxide circulating within the heat exchanger 1 under the second pressure, wherein the second pressure is lower than the first pressure. Therefore, the tube 10 being subject-matter of the inventions is suitable for so-called internal heat exchangers.

[0033] Further paragraphs discuss the main components of the tube 10 suitable for being implemented in such heat exchanger, and the mechanical or structural features thereof which ensure improvement in terms of efficiency with respect to known heat exchangers.

[0034] As shown for example in Fig. 1, the tube 10 being the subject-matter of the invention may comprise a first rectilinear section 11 and at least one second rectilinear section 12. The term rectilinear suggests that the intended flow of the fluid in this sections should be straight. The tube 10 may transfer any fluid, but in further paragraphs terms such as first fluid, second fluid, etc. may be used. The intension is to distinguish two different fluids in case more than one tube 10 is present (for example in heat exchanger).

[0035] It should be noted that the tube 10 is a unitary element made in extrusion process, wherein said tube 10 further comprises a plurality of micro-channels. In other words, each tube may be made out of piece of metallic material (e.g. aluminum) which undergoes the extrusion process. The micro-channels in Fig.1 are shown schematically. The number and / or shape of the micro-channels may be adapted by those skilled in the art.

[0036] Each rectilinear section 11, 12 may comprise two juxtaposed longer walls 13 having essentially flat surface connected by a pair of shorter walls 14 to form a closed profile of the tube 10. In other words, the longer walls 13 are substantially identical wall portions arranged in parallel and facing each other with their respective flat surfaces, as shown in detail section A-A' of Fig.1. The rectilinear sections 11, 12 may also comprise two shorter walls 14 connecting the longer walls 13 to form a closed profile of the tube 10. The rectilinear sections 11, 12 may also comprise an axis of elongation.

[0037] The tube 10 may further comprise two open ends 19. The term open end refers to a terminal ends of, for example, rectilinear sections 11, 12 which allows the fluid to enter or exit the entire tube 10.

[0038] The rectilinear sections 11, 12 are arranged at the same level, so that the respective longer walls 13 are coplanar with respect to each-other. In other words, surface of the longer wall 13 of the first rectilinear section 11 should be coplanar at least with the corresponding surface of the longer wall 13 of the second rectilinear section 12, irrespectively how the axis of elongation of the first rectilinear section 11 is arranged with respect to the axis of elongation of the second rectilinear section 12.

[0039] In order to fluidly connect the first rectilinear section 11 and the second rectilinear section 12, the tube 10 may further comprise at least one bent section 15. The bent section 15 may be arranged between the first rectilinear section 11 and the second rectilinear section 12.

[0040] The bent section 15 aims to provide a tube 10 which is bent along either of its shorter walls 14. It allows the path for the fluid to remain at the same length as the straight tube counterpart, yet the packaging in at least one of the dimensions is significantly reduced.

[0041] Consequently, the bent section 15 is arranged within the outline delimited by the longer walls 13 of neighboring rectilinear sections 11, 12. Ideally, the surface of the bent section 15 is ideally flat, yet some deviations may be formed.

[0042] As already discussed, the tube 10 is configured for circulation of the fluid therein. Accordingly, the first rectilinear section 11 is configured to provide a first intended fluid flow path F1 whereas the second rectilinear section 12 is configured to provide a second intended fluid flow path F2. The flow paths F1, F2 are shown in the drawings by respective arrows. It is apparent that the first rectilinear section 11 and the second rectilinear section 12 provide a substantially straight path for the fluid. The term substantially straight suggests that the micro-channels in the first rectilinear section 11 and the second rectilinear section 12 are ideally straight, yet an embodiment where tube 10 comprises a wavy structure, so wavy micro-channels and consequently- wavy flow paths F1, F2 could be also considered. However, such tube 10 would be very costly and it would require a very precise manufacturing process.

[0043] In order to minimize the packaging of the tube 10 in at least one of the directions while keeping the tube 10 itself as long as possible (i.e. provide the longest possible path for the fluid), the bent section 15 is configured to deflect the second intended fluid flow path F2 with respect to the first intended fluid flow path F1. Consequently, a direction and / or a sense of the second intended fluid flow path F2 is different to the first intended fluid flow path F1. The direction of flow relates to the line of flow of the fluid, and the sense is the way in which this fluid would move along that line. For example in so-called counter flow, the direction of two lines in two neighboring flow paths F1, F2 may be parallel, whereas the sense is indicated by arrows pointing the opposite directions.

[0044] The presence of the bent section 15 brings many advantages. It decreases the packaging of the tube 10, increases the thermal performance thereof, and allows stacking multiple tubes 10 of the same type one above the other, so that they are in contact not only with their respective longer walls 13, but also with respective surfaces of the bent sections 15, what significantly increases the heat exchange surface, and thus promotes the heat exchange.

[0045] For the reasons given in paragraphs above, the bent section 15 further comprises two juxtaposed flat sections 15C having essentially flat surface. The flat sections 15C may be connected by a first deflection 15A, and a second deflection 15B. The first deflection 15A and the second deflection 15B may be regarded as a portion of the bent section having a curvature. Said curvature is of predetermined radius. This allows a smooth transition between the first rectilinear section 11, the second rectilinear section 12, so that the micro-channels of the tube 10 are not damaged. As the first deflection 15A is located on one end of the flat section 15C and the second deflection 15B is located on the other side of the flat section 15C ( i.e. they are opposite with respect to each other), the second deflection 15B is different than the first deflection 15A. The difference may be regarded as, for example as the total length of the first deflection 15A and the second deflection 15B. The length of the deflections 15A, 15B, should be measured along the edges which are arranged outermost with respect to the flat section 15C. For example, the first deflection 15A may be longer than the second deflection 15B. Alternatively, the first deflection 15A may be shorter than the second deflection 15B.

[0046] As the tube 10 is a unitary element, the actual frontier between the first rectilinear section 11 / the second rectilinear section 12 and the bent section 15 may be uneasy to see. The ones skilled in the art should thus notice that the first rectilinear section 11 and / or the second rectilinear section 12 ends at the furthermost point of the respective sidewalls 14 which are linear. Thus the bent section 15 begins at the point where the curvature is present, thus indicating the beginning or the end of the first deflection 15A and second deflection 15B, respectively. The examples of how the tube 10 may be divided into the bent section 15 and respective rectilinear sections 11, 12 is shown in the figured by dotted line.

[0047] It is preferable that the bent section 15 is substantially U-shaped, so that the first intended fluid flow path F1 is arranged in counter-flow with respect to the second intended fluid flow path F2, as shown in Fig. 1-2 and in Fig. 4. The U-shape provides optimal packaging of the tube 10. However, the invention allows providing other shapes of the tube 10 as well. If required by customer, the bent section 15 may substantially L-shaped, so that the first intended fluid flow path F1 at the right angle with respect to the second intended fluid flow path F2. Alternatively, the bent section 15 may substantially V-shaped, so that the first intended fluid flow path F1 at the acute angle with respect to the second intended fluid flow path F2. This allows the great flexibility in terms of shape of the tube 10.

[0048] In order to further decrease packaging or make the path for the fluid longer, the tube 10 may comprise two or more bent sections 15. As consequence, the tube 10 may have a meandering shape (or an S-shape), as shown in Fig. 3 and in Fig. 7. The meandering shape of the tube indicates that there are three or more consecutive rectilinear sections 11, 12. For the sake of clarity, the third rectilinear section, the fourth rectilinear section, etc. are simply referred to as second rectilinear section 12, as there is no major structural difference between them. Those skilled in the art would easily distinguish that increases number of bent sections 15 increases the number of second rectilinear sections by one. Generally speaking, if N is the number of bent sections 15, then N+1 is the number of rectilinear sections 11, 12 associated with the tube 10.

[0049] In order to provide a design tailored to the requirements, the first rectilinear section 11 may comprise a first length L1, the first length L1 being measured in parallel with respect to axis of elongation of the first rectilinear section 11. Similarly, the second rectilinear section 12 may comprise a second length L2, the second length L2 being measured in parallel to axis of elongation of the second rectilinear section 12. In one of the embodiments, the first length L1 is equal to the second length L2. Alternatively, the second length L2 may be different (e.g. greater / smaller) than the first length L1.

[0050] Another object of the invention is heat exchanger 100 comprising at least one tube 10 described above. The examples of the heat exchanger 100 are shown in Fig. 4- Fig. 7.

[0051] The exchanger 100 is configured to provide a heat exchange between a first fluid and at least a second fluid. In case the heat exchanger 100 is internal heat exchanger (IHX), the first fluid may be high-pressure refrigerant (e.g. R744 / R290), and the second fluid may be the low- pressure refrigerant (e.g. R744 / R290).

[0052] Referring to Fig. 4, the heat exchanger 100 may comprise at least a first core 103. The core 103 comprises a plurality of tubes 10 stacked together in a first stacking direction. The first stacking direction is perpendicular to the first / second intended fluid flow direction F1, F2 in the tubes 10. In other words, the tubes 10 forming the core 103 may be arranged one above the other, so that their outer perimeters overlap. In the heat exchanger 100, the core 103 seems to be unitary element as the tubes 10 are brazed together, yet one must bear in mind that the core is in fact formed by two or more standalone tubes 10.

[0053] The heat exchanger 100 may further comprise: a first manifold 101 comprising a first axis of elongation. The first axis of elongation is arranged in parallel with respect to the first stacking direction of the tubes 10. Naturally, the greater number of tubes 10, the bigger the core, and thus the manifold must be elongated accordingly. Similarly, the and a second manifold 102 comprises a second axis of elongation being parallel to the first axis of elongation. The core 103 is configured to provide a fluidal communication between said first manifold 101 and a second manifold 102.

[0054] As there is a first fluid and the second fluid flowing in the heat exchanger 100, the core 103 may be divided into two (or more, if a third fluid is present) sections to enable the heat exchange in the core 103.

[0055] Therefore, the core 103 may comprise a first tube set 103A configured for circulation of a first fluid, and at least a second tube set 103B configured for circulation of a second fluid. In order to enhance the overall efficiency of the heat exchanger the tubes 10 forming the first tube set 103A may be arranged alternately with the tubes 10 forming the second tube set 103B. In other words, the tubes 10 forming the second tube set 103B may be interlaced with the tubes 10 forming the first tube set 103A.

[0056] The first manifold 101 may further comprise a first header 101A configured to receive one end of the core 103, a first cover 101B, and a first distribution plate 101C sandwiched between the first cover 101B and the first header 101A.

[0057] Analogically, the second manifold 102 may comprise a second header 102A configured to receive the other end of the core 103, a second cover 102B, and a second distribution plate 102C sandwiched between the second cover 102B and the second header 102A.

[0058] As the first manifold 101 and the second manifold 102 are substantially similar in terms of features, only the features of the first manifold are described in further paragraphs. For the same reason Fig. 6 shows the cross-section of one manifold, for example the first manifold 101, yet the features presented therein are also applicable to the second manifold 102. Thus, the first manifold 101, and the second manifold 102 may be simply referred to as the manifolds 101, 102. The same applies to other sub-components of the manifolds 101, 102.

[0059] The first cover 101B may comprise at least one channel 901A fluidly connected with the first tube set 103A, and at least one second channel 901B fluidly connected with the second tube set 103B. The channels 901A, 901B are fluidly insulated from each other within the manifold 101, 102. The fluidal insulation between the channels 901A, 901B is supported by the distributions plates 101C, 102C as they comprise an orifices that provide the fluidal communication between the core 103 and the respective channels 901A, 901B.

[0060] Accordingly, the tubes 10 of the first tube set 103A may be fluidly connected directly with the first channels 901A, whereas the tubes 10 of the second tube set 103B may be fluidly connected directly with the second channels 901B. As the first tube set 103A is responsible for transferring the first fluid, i.e. high pressure fluid, it is preferable that it is fluidly connected with the first channels 901A, which in this case is located closer to the core 103 than the second channel 901B. Consequently, the second tube set 103B is fluidly connected with the second channels 901B. This allows low pressure refrigerant to be connected directly in-line with the inlet for the heat exchanger 1 which significantly reduces pressure drop. Therefore it is preferred that the tubes 10 of the second tube set 103B protrude further into the manifold 101,102 than the tubes 10 of the first tube set 103A. Generally speaking, the tubes forming the second tube set 103B may be longer than the tubes forming the first tube set 103A.

[0061] Advantageously, each of the headers 101A, 102A comprises a slot 801. The slot 801 is adapted to the shape of the core 103 to provide fluid- tight assembly. As the slot 801 slot configured to receive the entire outline of the core 103, only one opening is required. This allows reducing the size of the core 103 and consequently, the size of entire heat exchanger 1. The shape of the slot 801 may be substantially rectangular, yet other shapes of the slot 801 are also envisaged.

[0062] The heat exchanger 1 may comprise an inlet and an outlet for the first fluid. Both inlet an outlet may be in form of openings fluidly connected to respective pipes of the refrigerant loop. The openings may also be connected indirectly, for example by means of connection block or other types of connectors. The pipes or the connection blocks may be fixed wherever suitable, depending on desired flow pattern or location of the inlet and outlet.

[0063] Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of drawings, the disclosure, and the appended claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to the advantage.

Claims

1. A tube (10) for a heat exchanger (1), comprising: a first rectilinear section (11) and at least one second rectilinear section (12) each rectilinear section (11, 12) comprises two juxtaposed longer walls (13) having essentially flat surface connected by a pair of shorter walls (14) to form a closed profile of the tube (10), wherein the rectilinear sections (11, 12) are arranged at the same level, so that the respective longer walls (13) are coplanar with respect to each-other, wherein the tube (10) further comprises at least one bent section (15) arranged between the first rectilinear section (11) and the second rectilinear section (12), wherein the bent section (15) is arranged within the outline delimited by the longer walls (13) of neighboring rectilinear sections (11, 12).

2. The tube (10) according to claim 1, wherein the tube (1) is configured for circulation of the fluid therein, wherein the rectilinear section (11) is configured to provide a first intended fluid flow path (F1), the second rectilinear section (12) is configured to provide a second intended fluid flow path (F2), wherein the bent section (15) is configured to deflect the second intended fluid flow path (F2) with respect to the first intended fluid flow path (F1), so that a direction and / or a sense of the second intended fluid flow path (F2) is different to the first intended fluid flow path (F1).

3. The tube (10) according to any of the preceding claims, wherein the tube (10) is a unitary element made in extrusion process, wherein said tube (10) further comprises a plurality of micro-channels.

4. The tube (10) according to any of the preceding claims, wherein the bent section (15) further comprises two juxtaposed flat sections (15C) having essentially flat surface, the flat sections (15C) being connected by a first deflection (15A), and a second deflection (15B), wherein the second deflection (15B) is different than the first deflection (15A).

5. The tube (10) according to any of the preceding claims, wherein the bent section (15) is substantially U-shaped, so that the first intended fluid flow path (F1) is arranged in counter-flow with respect to the second intended fluid flow path (F2).

6. The tube (10) according to any of the preceding claims, wherein the tube (10) comprises two or more bent sections (15) so that the tube (10) has a meandering shape.

7. The tube (10) according to any of the preceding claims, wherein the first rectilinear section (11) comprises a first length (L1), the first length (L1) being measured in parallel with respect to axis of elongation of the first rectilinear section (11), the second rectilinear section (12) comprises a second length (L2), the second length (L2) being measured in parallel to axis of elongation of the second rectilinear section (12), wherein the first length (L1) is equal to the second length (L2).

8. The tube (10) according to any of claims 1-6, wherein the first rectilinear section (11) comprises a first length (L1), the first length (L1) being measured in parallel with respect to axis of elongation of the first rectilinear section (11), the second rectilinear section (12) comprises a second length (L2), the second length (L2) being measured in parallel to axis of elongation of the second rectilinear section (12), wherein the first length (L1) is different than the second length (L2).

9. A heat exchanger (100) comprising at least one tube (10) according to any of the preceding claims.

10. The heat exchanger (100) according to claim 9, wherein said heat exchanger (100) is configured to provide a heat exchange between a first fluid and at least a second fluid, the heat exchanger (100) further comprising at least a first core (103) comprising a plurality of tubes (10) stacked together in a first stacking direction, wherein the heat exchanger (100) further comprises: a first manifold (101) comprising a first axis of elongation and a second manifold (102) comprising a second axis of elongation being parallel to the first axis of elongation, wherein the core (103) is configured to provide a fluidal communication between the first manifold (101) and a second manifold (102).

11. The heat exchanger (100) according to claim 10, wherein the core (103) comprises a first tube set (103A) configured for circulation of a first fluid, and at least a second tube set (103B) configured for circulation of a second fluid, wherein the tubes (10) forming the first tube set (103A) are arranged alternately with the tubes (10) forming the second tube set (103B).

12. The heat exchanger (100) according to claim 11, wherein the first manifold (101) comprises a first header (101A) configured to receive one end of the core (103), a first cover (101B), and a first distribution plate (101C) sandwiched between the first cover (101B) and the first header (101A), and wherein the second manifold (102) comprises a second header (102A) configured to receive the other end of the core (103), a second cover (102B), and a second distribution plate (102C) sandwiched between the second cover (102B) and the second header (102A), wherein each of the first cover (101B) and the second cover (102B) comprises at least one channel (901A) fluidly connected with the first tube set (103A) and at least one second channel (901B) fluidly connected with the second tube set (103B), wherein the channels (901A, 901B) are fluidly insulated from each other.

13. The heat exchanger (100) according to claim 11, wherein each of the headers (101A, 102A) comprises a slot (801), the slot (801) being configured to receive the entire core (103).

14. The heat exchanger (100) according to any of claims 9-13, wherein the heat exchanger (100) is internal heat exchanger.

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