WO2025026773A2 - Finned heat exchanger - Google Patents

Abstract

The invention relates to a finned heat exchanger, wherein the manufacturing effort is reduced compared to a conventional round-tube heat exchanger for the same heat transfer capacity. The problem addressed is solved with a finned heat exchanger in which the finned structure consists of a continuous sheet of metal that is slotted and bent in such a way that connecting webs are located approximately at mid-height between the fins, above which the fins are interrupted. A meander in the tube bent from a single piece can be placed in these interruptions and connected, e.g. glued, to the connecting webs with good thermal contact.

Description

finned heat exchangers

The invention relates to a finned heat exchanger for heat transfer between a gaseous medium and a second medium, with a pipe for the second medium and fins arranged transversely thereto, usually made of aluminum, for increasing the surface area for the gaseous medium, wherein the fins each have recesses for receiving the pipe.

Furthermore, the invention relates to a finned heat exchanger for heat transfer between a gaseous medium and a second medium, with

- a pipeline for the second medium, which extends in a z-direction,

- a lamellar structure consisting of a continuous sheet of metal that is alternately bent upwards and downwards,

- wherein the lamellar structure has a plurality of lamellae arranged transversely to the z-direction and spaced apart from one another by gaps in the z-direction to increase the surface area for the gaseous medium,

- the slats each have a lower edge and an upper edge,

- wherein the lower edges of the lamellae lie in a base plane which extends in the z-direction and in an x-direction arranged transversely thereto,

- wherein the lamellar structure has open spaces between the lamellae for the gaseous medium in the x- and y-direction,

- wherein the sheet is provided with slots which separate the slats from connecting webs, and wherein the slats have interruptions above the connecting webs, between which recesses are arranged. With such a finned heat exchanger, heat transfer from the gaseous medium, e.g. air, to the second medium is possible in both directions, ie the gaseous medium is cooled or heated. The second medium can also be gaseous or liquid, or undergo a phase change during the heat transfer, i.e. evaporate or condense.

Such finned heat exchangers are required in many different applications, e.g. as a cooler for cooling a liquid medium with air or as a heat exchanger of an air-water heat pump for extracting heat from the ambient air or, if the heat pump or air conditioning system is used to cool a building, for releasing heat to the ambient air.

Commonly used for this purpose are finned heat exchangers with an enlarged surface area to the air or gaseous medium. Different designs are used to increase the surface area, with the most common being two different types of finned heat exchangers:

Round tube finned heat exchanger: The fins are perpendicular to the round tubes through which the second medium flows, see e.g. https://www.polarkaeltetechnik.de/pdf/Polar_Lamellenwaerrnetau- scher_DE_EN.pdf

Rectangular or flat channel or microchannel heat exchanger with folded fins between the rectangular channels through which the second medium flows, see e.g. https://youtu.be/SPPtDqOzc-s

A special application of finned heat exchangers is described in EP 3 497 381 B1 for a PVT collector (photovoltaic thermal collector): A round tube finned heat exchanger is located on the back of a PV module. The fins lie in thermally conductive contact with the PV module and are glued to the PV module to ensure contact. The fins increase the surface area to the ambient air compared to the surface of the photovoltaic module and thus increase the heat exchange in the Improved compared to conventional PVT modules. Free spaces of typically 10-50 mm are provided between the fins to allow good airflow around both the heat exchanger and the back of the PV module and to prevent the gaps from being blocked by icing. The pipes are located at a certain distance from the PV module, for example in the middle between the outer edge of the fins and the PV module, to optimize the heat transfer from the air and minimize possible icing of the PV module.

A general disadvantage of round tube finned heat exchangers is the relatively complex manufacturing process in numerous steps: The fins are punched out of a sheet of metal, holes with collars are cut out for the round tubes, round tubes are bent into U-bends, the fins are threaded onto the U-bends, the round tubes are expanded using inserted domes so that the collars of the fins sit firmly on them, and finally short 180° bends are soldered onto the open ends of the U-bends. A disadvantage, for example in the application for the PVT collector described in EP 3 497 381 B1, is that the fin spacing is limited for manufacturing reasons: the spacing is defined by the collared collars of the fins, and the necking is limited to approx. 10 to max. 12 mm for a typical fin thickness of 0.2 mm. In the application mentioned, a larger distance leads to a better free flow around the slats up to the PV module. This means that the material used can be reduced while maintaining the same heat output, and at the same time the possibility of the gaps becoming blocked by ice is minimized.

A larger slat spacing is particularly necessary if the space between the PV module and the roof, the facade or a rear wall as in DE 20 2022 000 161 U1 is to be as small as possible, since if the air is to flow by free convection, especially between the slats, the flow resistance is too great with a slat spacing of 10-12 mm. Furthermore, studies have shown that lateral air exchange also has a strong positive influence on high heat transfer performance. However, due to the closed shape, cross-flow in the z-direction is not possible between the slats, only behind the slats, e.g. between the slats and the roof, which requires a larger distance to the rear wall and leads to poorer heat transfer than if the air could flow directly crosswise between the slats.

DE 20 2015 103 440 U1 describes a finned heat exchanger in which, in contrast to the method described above, at least one meandering pipe made of aluminum is used, formed from a single piece. Between pipe sections of a pipeline, fins are arranged one behind the other in the longitudinal direction of the pipe sections, known as guide plates. These guide plates have receptacles on one side at the edge, on which collars extending in the longitudinal direction of the pipe sections are arranged, against which respective wall sections of the pipeline rest. The guide plates are integrally connected to the wall sections of the pipeline in the area of the collars. A disadvantage of this heat exchanger design is the relatively high manufacturing effort for the precise arrangement of all individual fins or guide plates on the pipeline from both sides, despite the pipeline being bent in a meandering shape from a single piece.

DE 10 2015 120 487 A1 also describes a finned heat exchanger with a meandering pipe made from one piece. Here, folded fins are used as in the microchannel heat exchangers described above, but combined with a round pipe: folded fins with embossed collars are attached to both sides of the pipe. The disadvantage of this arrangement is that the gaseous medium can only penetrate from the outside to the middle, where the fin folds, which rules out an application such as that described in EP 3 497 381 B1. DE 10 2017 112 063 A1 shows a finned heat exchanger in which a pipe intended for heat transfer is also enclosed on both sides by two wave-shaped folded fin structures. In this case, the wave-shaped fins are closed at the fold or bend, as in DE 10 2015 120 487 A1, so that here too the gaseous medium can only penetrate from the outside to the middle, with the same disadvantage as in DE 10 2015 120 487 A1.

DE 27 28 472 A1 discloses a finned heat exchanger of the type mentioned at the beginning, which also provides fins connected to one another by an “accordion-like” fold with semicircular collars for the contact surface to the heat exchanger pipe. This finned heat exchanger has two folded finned structures which are placed on the pipeline from both sides during manufacture of the finned heat exchanger and are connected to one another by hooks bent into the finned sheets. The disadvantage of this arrangement is again the effort involved: two finned structures are always required and these must be connected to one another. Furthermore, the connecting webs which connect the fins at the upper and lower ends hinder the free exchange of air between the fins, particularly in the y-direction, see e.g. page 8, third paragraph of this document. This would be particularly noticeable in applications with free convection, such as in the case of conventional heating systems. This can have a negative effect, for example, on a structure according to EP 3 497 381 B1, where the air is also supposed to enter perpendicular to the arrow shown in Figure 15, i.e. from top to bottom. If the webs are made narrow in order to minimize the obstruction, the unit becomes fragile, which, among other things, makes efficient production more difficult.

A further disadvantage, as with DE 20 2015 103 440 U1, is that punching with waste is required to realize the lamella structure, i.e. the processed sheet surface is not fully used as a heat exchanger surface. Round tube finned heat exchangers are often manufactured with copper tubes and aluminum fins in building heating and cooling applications when a fluid flows through them, as copper tubes offer greater corrosion resistance than aluminum tubes, for example, especially in mixed installations - i.e. when different metals are used in the same hydraulic circuit. Curved copper tubes can also be manufactured with thinner walls than aluminum tubes, so that the difference in costs compared to aluminum tubes is not great, depending on the price of the metal. However, one disadvantage of the combination of copper tubes with aluminum fins is the increased risk of corrosion at the contact points between copper and aluminum, which is why such heat exchangers for applications in corrosive environmental conditions are usually equipped with a coating, which in turn increases the costs.

Microchannel heat exchangers can be produced with fewer work steps and therefore lower production costs. A disadvantage of microchannel heat exchangers is the relatively high material expenditure required to produce the rectangular channels, as certain wall thicknesses cannot be exceeded in the extrusion process. The application for the PVT collector described in EP 3 497 381 B1 is only possible without folded fins, as otherwise the air cannot flow freely between the channels. In this application, the surface area required for heat transfer would therefore have to be created by a correspondingly high number of microchannels, and the material used would be significantly larger than for a round tube fin heat exchanger with the same area. In addition, a microchannel cools the PV module directly, which can lead to unwanted icing.

The object of the invention is to present a finned heat exchanger according to the preamble of patent claim 1 or of patent claim 10, in which the manufacturing effort compared to a classic round tube finned heat exchanger in relation to the same heat transfer capacity is reduced. In addition, the finned heat exchanger should enable low material costs during its production.

Corrosion risks should be minimised even without a coating. For applications with free convection in external heat transfer, for example, a larger fin spacing than 10 to 12 mm should be possible, and the external heat transfer, which represents the greatest resistance in the entire thermal resistance chain, should be improved compared to a conventional round tube fin heat exchanger: Cross flow between the fins in the z direction should be possible.

The above-mentioned object is achieved with respect to a finned heat exchanger according to the preamble of patent claim 1 in that the recesses are designed as receptacles for the pipeline and that the pipeline is arranged in the recesses.

The slats, including the defined spacers created by the connecting webs, can be manufactured in a continuous process from a piece of sheet metal that is rolled off a roll, for example. When producing the slat structure, the sheet metal can be slit, for example using a punching process, and then pressed into a zigzag shape.

The pipe can be designed as a meander pipe bent from one piece, which is inserted into the interruptions of the fins and into the recesses arranged between them during the manufacture of the finned heat exchanger and is connected to the connecting webs in a material-locking or form-fitting manner with good thermal contact.

The sheet is provided with slots that separate non-bent sections of the sheet as vertical or inclined slat sections from bent sections as connecting webs. Since in the thermal resistance chain, particularly in the case of free convection, the heat transfer between air or gaseous medium and the lamella represents the greatest thermal resistance, improvements are most effective here, while deteriorations, e.g. due to gluing of the pipe and lamellae instead of a metallic connection or a plastic layer on the inside and possibly also the outside of the pipe, have comparatively little effect if dimensioned accordingly. Therefore, in a preferred embodiment of the invention, it is provided that the lamella structure has at least two rows of lamellae running parallel to one another, in each of which several lamellae are arranged one behind the other offset in the z direction, and

- that the lower edges of the slats of a first row of slats are offset from each other in the z-direction with a gap between them and the lower edges of the slats of a second row of slats, the slats of which are each connected via a connecting web to a slat of the first row of slats assigned to it, and/or

- that the upper edges of the slats of the first row of slats and the upper edges of the slats of the second row of slats, the slats of which are each connected via a connecting web to a slat of the first row of slats assigned to it, are offset from one another in the z-direction.

The fins are preferably arranged alternately between the connecting webs on one side or the other of the connecting web. Due to the offset fins, air flowing parallel to the fins in the x-direction repeatedly encounters a new fin, and air exchange across the fins in the z-direction is also easier. This improves the heat transfer between air or gaseous medium and fin compared to a classic design of a round tube fin heat exchanger.

In the embodiment described above, the pipe can also be bent from one piece in an endless process and with the folded slats be connected in a thermally conductive manner, e.g. by gluing, welding or soldering, e.g. in an oven, or by mechanical pressing. To bond the pipe and the louvre sheet, the connecting web can be embossed, the contour of which corresponds to the cross-section of the pipe, to accommodate the pipe with good contact. In the case of a round pipe, the embossing is therefore in the shape of a circular segment. Alternatively, the pipe can be shaped so that it has a flattened cross-section on the contact surface with the connecting piece of the louvre sheet, which in this case is flat.

In an advantageous embodiment of the invention, slats are provided with bevels on their upper and/or lower edges, which have contact surfaces. The contact surfaces can be used, for example, to apply adhesive to connect to a surface, e.g. the surface of a PV module. At the same time, the bevels ensure greater stability of the slat structure.

It is advantageous if the edges of the slats adjacent to the interruptions have a shape which is geometrically adapted to an outer contour region of a pipeline facing it and is designed in particular as a negative form of this outer contour region, and if these edges preferably receive the pipeline in such a form-fitting manner that the pipeline is in thermal contact with the connecting web.

In a further advantageous embodiment of the invention, the connecting webs have a shape that is geometrically adapted to an outer contour area of a pipeline facing them and is designed in particular as a negative form of this outer contour area, wherein the connecting webs preferably come into contact with the outer contour area of the pipeline in a flat manner. This measure also enables good thermal contact between the pipeline and the lamellar structure.

In an expedient embodiment of the invention, the connecting webs are designed flat, whereby the pipeline has a flattened cross-section which lies flat against the connecting webs. The pipeline can be cylindrical or rounded in some other way outside the flattened cross-section.

It is advantageous if the connecting webs have a preferably tab-shaped widening on at least one side, which is shaped so that it rests laterally on the pipe and increases the contact area. The connecting webs can therefore be widened on the sides with wings that are shaped so that they rest laterally on the pipe and thus increase the contact area. The contour of the connecting webs thus formed can be designed so that there are areas that do not rest on the pipe and in which there is adhesive and other areas that are in direct contact with the pipe.

All measures - adjustment of the contour of the connecting web and the cross-section of the pipeline as well as widening of the support surface by means of wings - can be combined with each other.

Fins and piping can be made of aluminum, preferably corrosion-resistant aluminum, so that an additional coating for corrosion protection is not necessary, especially because there are no contact points between different noble metals.

The above-mentioned object is achieved with regard to a finned heat exchanger according to the preamble of patent claim 10 in that the pipeline consists of an aluminum-plastic composite pipe with plastic on the inside and a preferably 0.2 mm to 0.5 mm thick aluminum layer on the outside, that the aluminum layer is designed in such a way that it conducts the heat transferred by the fins over the entire pipe circumference and the areas between the fins, and that the pipeline is bent from one piece. The aluminum-plastic composite pipe has the advantage of corrosion protection, particularly on the inside, for example in mixed installations or in installations where it cannot be ruled out with certainty that traces of copper will enter the circuit during processing or assembly. Calculations show that a technically feasible plastic layer of approx.

0.7...0.8...0.9 mm with a total outer diameter of e.g. 14 mm results in an acceptably small reduction in the total heat transfer.

For the aluminum layer, as well as for the fins, an alloy that is sufficiently corrosion-resistant for the application is selected. This means that a plastic coating on the outside is not necessary. In this way, good thermal contact between the fins and the pipe is possible and the heat transferred there can be conducted through the aluminum layer over the entire circumference of the pipe and the areas between the fins and transferred inwards. The connection between the pipe and the fins can then be made not only by gluing but also by welding with very limited local heat generation, e.g. by ultrasonic welding or laser welding. With ultrasonic welding, a sonotrode can roll along the underside of the connecting webs on which the pipeline rests. With laser welding, for example, parts of the connecting web can be melted from the outside using the laser beam and welded to the aluminum layer of the pipe.

The plastic layer inside and an aluminum layer outside allows for a thinner aluminum layer of approx. 0.2 mm to approx. 0.5 mm than with a pure aluminum tube for several reasons and thus a lower weight and at least lower material costs:

- From a manufacturing point of view, thin-walled aluminium tubes with wall thicknesses in the range of 0.3 mm are difficult to produce without a plastic composite.

- Aluminium composite pipe with thin-walled aluminium tube can be bent more tightly than pure aluminium tube of the same thickness. The corrosion protection and secure sealing provided by the plastic inner tube allows for lower safety and therefore material thicknesses for aluminum.

Often, finned heat exchangers also contain a distribution and collector pipe or a distribution and collector channel. The connection between the pipeline or the pipe meander and these pipes is usually made by soldering or welding. If the pipe meander and distribution and collector pipes are each made of aluminum, the connection can be designed as a soldered or welded connection, for example. If the pipeline is an aluminum-plastic composite pipe, a transition piece made of plastic or another material can be attached to both meander ends by (plastic) welding or gluing. This transition piece can also be welded or glued to a distribution and collector pipe made of plastic or aluminum-plastic composite.

In an advantageous embodiment of the invention, the pipeline is connected to aluminum fins of a finned structure by a weld seam, in particular an ultrasonic or laser beam weld seam. During the manufacture of the finned heat exchanger, the ultrasonic or laser beam weld seam can be introduced into the fin and the pipeline by a spatially very limited introduction of heat.

Further advantageous embodiments of the invention are described in the subclaims.

In the following, embodiments of the invention are explained in more detail with reference to the drawing. It shows:

Fig. 1 is an isometric partial view of a first embodiment of a lamellar structure, Fig. 2 is an isometric partial view of a second embodiment of the lamella structure,

Fig. 3 is an isometric view showing a larger area of the lamella structure of the second embodiment than Fig. 2,

Fig. 4a a flat sheet with slots, from which a third embodiment of the lamellar structure can be produced by bending,

Fig. 4b to 4c an isometric view of the sheet shown in Fig. 4a, showing the sheet in different states of bending deformation,

Fig. 5 is an isometric partial view of a fourth embodiment of the lamella structure,

Fig. 6 is an isometric partial view of a fifth embodiment of the lamella structure,

Fig. 7 is an isometric partial view of a sixth embodiment of the lamella structure, showing a connecting web which is widened on both sides by wings,

Fig. 7a shows a partial cross-section through a finned heat exchanger having the finned structure according to Fig. 7 and a pipe connected to the connecting web in a heat-conducting manner,

Fig. 8 is an isometric partial view of a seventh embodiment of a lamellar structure,

Fig. 9 is an isometric view of the piping of the finned heat exchanger shown in Fig. 10, Fig. 10 is an isometric partial view of a finned heat exchanger,

Fig. 11 is a partial isometric view of a pipeline having a rounded cross-section with a flattened cross-sectional area,

Fig. 12 is an isometric view of the connection between a meandering pipeline and a distribution or collecting pipe, and

Fig. 12a shows a cross-section through the connection shown in Fig. 12.

Figure 1 shows a finned structure 1 of a finned heat exchanger 9 bent from a piece of sheet metal (shown in Figure 10). The fins 2 made of non-bent sheet metal are divided into sections, between which there is a bent sheet metal section as a connecting web 3 to the next fin. The fins themselves have no beveled surfaces in this design. Gaseous medium can flow between the fins in both the longitudinal direction y and the transverse direction x. The connecting webs 3 form recesses between the finned sections 2, which serve as a receptacle for a pipe 7 inserted from above (see Figure 10).

Figure 2 shows a variant of the slatted structure 1 bent from a piece of sheet metal. Here, the slats 2 have bent surfaces 4 on the underside, which can be used, for example, to apply adhesive to connect to a surface such as a PV module. At the same time, the bevels 4 ensure greater stability of the slatted structure 1. The bent surfaces and an adjoining area of the slats are provided with slots 5a in order to minimize thermal stresses due to different thermal expansion coefficients of the slats and surface (e.g. PV module).

Figure 3 shows a larger area of the lamellar structure 1 . Figure 4a shows the sheet 1a of the lamellar structure 1 with slots 5b and 5a before the sheet was bent.

Figures 4b to 4c show the sheet metal in which the bending was carried out with successively larger bending angles and thus illustrate the construction of the lamella structure 1 from a sheet metal. According to the invention, lamella structures 1 with different bending angles are possible, as are partial bends of the lamellas 2, e.g. in the middle area between the lower support surface and the top around the x-axis. Bending and shaping embossing transverse to this, i.e. around the y-axis, are also possible. This allows the geometry to be optimized, e.g. with regard to the flow around it, depending on the application.

Figure 5 shows a section of the lamella structure 1 with a shape 2a of the edges of the lamella sections 2, which can accommodate a pipe with at least a partially circular cross-section. This achieves a positive connection between a pipe 7 and connecting webs 3. In the figure, the contour 2a at the top is drawn as converging to an exaggerated extent and without radii in order to illustrate the principle. The pipe 7 is connected to the connecting webs 3 of the lamellas 2 by mechanical pressing. However, other designs are also conceivable in which the pipe 7 is connected to the connecting webs 3 of the lamellas 2 by an adhesive, a weld seam or a solder.

Figure 6 shows the lamellar structure 1 with connecting webs with circular segment-shaped embossing 3a for receiving a pipe 7 with a circular cross-section with good contact.

Figure 7 shows a connecting web 3 which is widened on the sides with wings 6, which are shaped in such a way that they rest laterally against a pipe 7 and thus increase the contact surface. Figure 7a shows the connecting web 3 with wings 6 and a pipe 7 in section. The connecting web 3 is located below and on the side. directly to the pipe 7. The areas that are not adjacent to the pipe are filled with adhesive 8 and create the material-tight connection.

Figure 8 shows a variant of the finned structure 1 of the finned heat exchanger 9, which is bent from a piece of sheet metal. Here, the connecting webs 3 are bent so that they converge downwards. In this way, the connecting webs 3 are so wide that they form a continuous support for the pipe 7. In Figure 8, bevels 4 are shown on the fins 2 at the bottom. However, this design is also possible without bevels 4, as shown in Figure 1, or with bevels 4 that only cover part of the area between the fins 2.

Figure 9 shows a pipe 7 bent from one piece or a meander pipe.

Figure 10 shows the pipe meander 7, which is inserted into a section of the lamellar structure 1 and which together form the lamellar heat exchanger 9.

Figure 11 shows a flattened cross-section 10 of a pipe meander 7 adapted to a flat connecting web 3.

Figures 12 and 12a show the connection between the pipe meander and a distribution or collector pipe, for example for applications such as in the

EP 3 497 381 B1, once from the outside (Figure 12) and once in section (Figure 12 a). Pipe 7 and distribution-collector pipe 11 consist of aluminum-plastic composite pipe with an aluminum layer on the outside. A transition piece

12 made of plastic is connected by plastic welding to both the end of the pipe 7 and the distribution-collector pipe 11. The radial bore

13 in the distribution-collector pipe 11 is conical. In this way, the cut surface of the outer aluminum layer of the composite pipe is safely protected from contact with the medium flowing within the distribution-collector pipe 11 and the pipeline 7, and thus from possible corrosion. The same applies to the Cutting surface of the pipeline 7, which is protected from contact with the medium by the sleeve piece 14 inserted into the pipeline and welded.

The advantages of the invention are:

The finned heat exchanger 9 can be produced with significantly fewer manufacturing steps than is usual for round tube finned heat exchangers:

The lamella structure 1 including defined spacers created by the connecting webs 3 can be manufactured in a continuous process from a piece of sheet metal, which is rolled off a roll, for example. The complete pipe meander 7 can also be bent from a roll in a continuous process from one piece, instead of individual U-tubes or channels that have to be soldered together. The folded lamella structure 1 and the bent pipe meander 7 and, if applicable, the surface to be connected to the lamella structure, such as a PV module, can be connected to one another in one step, e.g. glued. A larger spacing between the lamellas than previously possible with round tube fin heat exchangers ensures, for example, better air exchange in the depth of the PV laminate and less material in this application. This and the offset fin sections result in an improved heat transfer to the fin for the gaseous medium compared to classic round tube or microchannel fin heat exchangers. When using aluminum-plastic composite pipes, the Al-Cu material combination that is common in round-tube finned heat exchangers is avoided, which minimizes the risk of corrosion and avoids the need for an external coating. If the outer shell of the aluminum-plastic composite pipe is made of aluminum, no expensive UV stabilization for the plastic is required. Furthermore, the use of aluminum, which is more expensive than plastic and requires a lot of energy to produce, can be minimized. At the same time, corrosion protection on the inside is increased.

Instead of the described embodiments, other embodiments are also possible according to the invention: for example, the slat sections 2 can all be connected on the same side of the connecting web 3 instead of being connected alternately and offset. Instead of bending the slats on one side, bending on both sides (top and bottom) is also possible.

Instead of the described design with distribution-collector pipe 11 without a plastic layer on the outside, the pipes 7 and/or 11 can also be provided with a plastic layer on the outside, e.g. for corrosion protection.

The invention relates to a finned heat exchanger 9 for heat transfer between a gaseous medium and a second medium, consisting of a pipe 7 for the second medium and fins 2 arranged transversely thereto for increasing the surface area for the gaseous medium, each of which has recesses for receiving the pipe 7, wherein a plurality of fins 2 as a finned structure 1 consist of a continuous sheet 1 a that is alternately bent upwards and downwards with horizontal sections in between, wherein the sheet 1 a is provided with slots 5b that separate non-bent sections of the sheet as vertical or inclined finned sections 2 from bent horizontal sections as connecting webs 3, wherein these horizontal sections form recesses between the fins 2 for receiving a pipe 7, so that, as with round-tube finned heat exchangers, there are open spaces between the fins 2 for the gaseous medium in both the transverse direction x and the longitudinal direction y.

Furthermore, the invention relates to a finned heat exchanger 9 for heat transfer between a gaseous medium and a second medium, consisting of a pipe 7 for the second medium and fins 2 arranged transversely thereto for increasing the surface area for the gaseous medium, each having recesses for receiving the pipe 7, wherein the pipe 7 consists of an aluminum-plastic composite pipe with plastic on the inside and aluminum on the outside and is bent from one piece. list of reference symbols

1 lamellar structure

1a sheet metal

2 slats

2a Contour of the slat for receiving the pipe

3 connecting web (bent sheet metal section)

3a Connecting bridge with circular segment-shaped embossing

4 Edge on slat or support surfaces

5a Slot as expansion joint

5b Slot in sheet metal to separate differently curved areas (lamellas 2 and connecting webs 3)

6 Lateral widening (“wing”) of the connecting web 3 or the support of the pipeline 7

7 Pipeline or pipe meander

8 adhesives

9 finned heat exchangers

10 flattened cross-section of a pipe meander 7

11 distribution manifold

12 transition piece

13 (conical) hole in the distribution manifold

14 Sleeve piece of the transition piece 12

15 spaces

16 lower edge

17 upper edge

18 Interruption

19 recess

20 first row of slats

21 second row of slats

Claims

patent claims 1 . A finned heat exchanger (9) for heat transfer between a gaseous medium and a second medium, with - a pipeline (7) for the second medium, which extends in a z-direction, - at least one lamellar structure (1) consisting of at least one continuous sheet (1a) which is alternately bent upwards and downwards, - wherein the lamellar structure (1) has a plurality of lamellae (2) arranged transversely to the z-direction and spaced apart from one another in the z-direction by gaps (15) for increasing the surface area for the gaseous medium, - wherein the slats (2) each have a lower edge (16) and an upper edge (17), - wherein the lower edges of the slats (2) lie in a base plane which extends in the z-direction and in an x-direction arranged transversely thereto, - wherein the lamellar structure (1) has gaps (15) between the lamellae (2) for the gaseous medium, which gaps are open in the x- and y-directions, - wherein the sheet metal (1a) is provided with slots (5b) which separate the slats (2) from connecting webs (3), and wherein the slats (2) have recesses (19) above the connecting webs (3), characterized in that several slats (2) consist of a continuous sheet metal (1a) as a slat structure (1), and that the recesses (19) are designed as receptacles for the pipeline (7), and that the pipeline (7) is arranged in the recesses (19) and is connected to the connecting webs (3) with thermal contact. 2. Lamellar heat exchanger (9) according to claim 1, characterized in that the connecting webs are arranged approximately at a middle height between the lower edge (16) and the upper edge (17) of the lamellar structure (1). 3. finned heat exchanger (9) according to claim 1 or 2, characterized in that the finned structure (1) has at least two parallel finned rows (20, 21), in each of which several fins (2) are arranged one behind the other offset from one another in the z-direction, and - that the lower edges (16) of the slats (2) of a first slat row (20) are offset from one another in the z-direction with a gap between them and the lower edges (16) of the slats (2) of a second slat row (21), the slats (2) of which are each connected via a connecting web (3) to a slat (2) of the first slat row (20) assigned to it, and/or - that the upper edges (17) of the slats (2) of the first slat row (20) and the upper edges (17) of the slats (2) of the second slat row (21), the slats (2) of which are each connected via a connecting web (3) to a slat (2) of the first slat row (20) assigned to it, are offset from one another in the z-direction with a gap. 4. Fin heat exchanger (9) according to one of claims 1 to 3, characterized in that fins (2) are provided on their upper edge (17) and/or lower edge (16) with bevels (4) which have support surfaces. 5. Fin heat exchanger (9) according to one of claims 1 to 4, characterized in that the edges of the fins (2) adjacent to the interruptions have a shape (2a) which is geometrically adapted to an outer contour region of the pipeline (7) facing it and is designed in particular as a negative form of this outer contour region. and that these edges preferably receive the pipe (7) in such a form-fitting manner that the pipe (7) is in thermal contact with the connecting web (3). 6. Fin heat exchanger (9) according to one of claims 1 to 5, characterized in that the connecting webs (3) have a shape which is geometrically adapted to an outer contour region of the pipeline (7) facing them and is designed in particular as a negative form of this outer contour region, and that the connecting webs (3) come to rest flatly on the outer contour region of the pipeline (7). 7. Fin heat exchanger (9) according to one of claims 1 to 6, characterized in that the connecting webs (3) are flat and that the pipe (7) has a flattened cross-section which lies flat against the connecting webs (3). 8. Fin heat exchanger (9) according to one of claims 1 to 7, characterized in that the connecting webs (3) have on at least one side a tab-shaped widening (6) which is shaped such that it rests laterally on the pipe (7) and enlarges the contact surface. 9. Fin heat exchanger (9) according to one of claims 1 to 8, characterized in that the pipe (7) is connected to the connecting webs (3) in a material-locking manner and in particular is glued or welded. 10. Fin heat exchanger (9) for heat transfer between a gaseous medium and a second medium, with a pipe (7) for the second medium and fins (2) arranged transversely thereto and spaced apart from one another by gaps (15), preferably made of aluminum, for increasing the surface area for the gaseous medium, wherein the fins (2) each have recesses for receiving the pipe (7), in particular according to one of claims 1 to 9, characterized in that the pipe (7) consists of an aluminum-plastic composite pipe with plastic on the inside and an aluminum layer on the outside, that the aluminum layer is designed such that it conducts the heat transferred by the fins (2) over the entire pipe circumference and the areas between the fins, and that the pipe (7) is bent from one piece. 11. Fin heat exchanger (9) according to claim 10, characterized in that the aluminum layer of the aluminum-plastic composite pipe has a thickness of 0.2 mm to 0.5 mm. 12. Fin heat exchanger (9) according to claim 10 or 11, characterized in that the pipeline (7) is connected to aluminum fins of a fin structure (1) by a welded connection, in particular an ultrasonic or laser beam connection. 13. Fin heat exchanger (9) according to claim 10 or 11, characterized in that the pipe (7) is connected to aluminum fins of a fin structure (1) by an adhesive connection. 14. Fin heat exchanger (9) according to one of claims 10 to 13, characterized in that the pipeline (7) is provided at least at one of the two pipe ends with a transition piece (12) with a sleeve piece (14) made of plastic, which is inserted into the pipeline and welded or glued to the pipe end of the pipeline (7) by plastic welding, and that this transition piece (12) is tightly connected to a distribution or collector pipe (11) made of plastic or aluminum-plastic composite. 15. Fin heat exchanger (9) according to claim 14, characterized in that the transition piece (12) is provided with a distribution or collector pipe (11) made of plastic or aluminum-plastic composite, which has a radial Hole (13), is tightly connected by being received in the hole (13) and welded or glued by plastic welding.