EP3143357B1 - Heat transfer device and use thereof - Google Patents

Description

The invention relates to a heat transfer device with channels for heat-absorbing media and channels for heat-emitting media, at least one of the channels having a textile structure with compressed and non-compressed areas. While the compressed areas are arranged in the transition areas between the channels to improve heat transfer on or over the channel wall, the non-compressed areas are arranged in the flow areas of the channels. This structure enables a large heat transfer to the heat transfer surface with good heat conduction from the heat transfer surface to the separating surface. The invention also relates to heat exchangers with such heat transfer devices.

The surface enlargement is of central importance in the phenomenon of heat transfer.

• Ausgleich stark unterschiedlicher Wärmeübergangskoeffizienten, indem in dem Medium auf der Seite mit dem geringeren Wärmeübergangskoeffizienten (z.B. Luft) eine vergrößerte Oberfläche zur Wärmeübertragung zur Verfügung gestellt wird,
• Erhöhung der Leistungsdichte von Wärmeübertragern durch kompaktere Bauweise,
• Erhöhung des Wärmeübergangs bei Siedeprozessen,
• Optimierung der Wärme- und Stofftransportkinetik bei Sorptionsprozessen/chemischen Reaktionen oder katalytischen Prozessen,
• Unterstützung kapillarer Transportvorgänge, und
• Be- und Entfeuchtung von Luft und anderen Gasen.

The following objectives are in the foreground:

• Compensation of very different heat transfer coefficients by providing an enlarged surface for heat transfer in the medium on the side with the lower heat transfer coefficient (eg air)
• Increasing the power density of heat exchangers through a more compact design,
• Increase in heat transfer during boiling processes,
• Optimization of heat and mass transfer kinetics in sorption processes / chemical reactions or catalytic processes,
• Support of capillary transport processes, and
• Humidification and dehumidification of air and other gases.

Depending on the application, the increase in power density (corresponds to the reduction in construction volume and / or the use of materials), the reduction in driving temperature differences, the reduction in pressure loss, the increase in yield through reduced cycle times or a combination of these variables are of interest.

For heat exchangers with large specific surfaces, plugged or soldered finned heat exchangers consisting of copper tubes and attached copper, aluminum or stainless steel fins as well as flat tube-based aluminum coolers, in which folded fins are soldered with extruded fluid channels, are of particular importance.

To achieve an energy-efficient, compact and material-saving heat transfer in flowing media, it is of central importance to achieve a high volume-specific surface as well as a contact surface between the separating surface and the surface enlargement that is as large as possible and as integral as possible. At the same time, the ways of heat conduction through the surface enlargement structure must be as short and direct as possible. Appropriate slots, dents, waves, etc. in the surface enlargement structure attempt to achieve the highest possible surface-specific heat transfer without disproportionately increasing the pressure loss to be overcome. The sizes that are currently achieved by the currently available heat exchangers are summarized in Table 1. Table 1: volume-specific area [m ² / m ³ ] Contact surface to the fluid structure [m ² / m ³ ] Type of contact Slats (flat, punched) 1250 55 Pressed Folded / corrugated slats 1340 65 Cohesive (soldered) Metallic short fibers 8,000-10,000 100 Soldered / sintered

Metallic short fiber structures are another possibility for producing large specific surfaces and a materially contacting the separating surface. These are poured onto one another, pressed and then soldered or sintered. A variation in density and porosity can be achieved by varying the fiber length and diameter. They achieve volume-specific surfaces of 8,000-10,000 m ² / m ³ and volume-specific separating surfaces between the two media in the range of 100 m ² / m ³ . However, the undefined orientation and arrangement of the fibers is disadvantageous for use in flowing media.

The combination of fabric mats and pipes is also an opportunity to enlarge surfaces.

In the DE 27 02 337 A1 the combination of flexible pipes and fabric mats is described, for example to implement surface heating. However, the focus of the invention is on flexible pipe laying, the fabric is only defined as a support structure and not as a specifically designed heat exchanger structure.

In the DE 31 24 379 A1 describes a wire mesh that is processed either by soldering with tubes or by weaving through flowable tubes into a heat exchanger. The fabric is evenly structured, the geometry is created by processing thicker wires or by unfolding the fabric mat. A dirt-repellent coating by Teflon is mentioned. Wire spacing and diameter are not specified in more detail.

Similarly, in the DE 34 27 251 A1 described a fabric with woven copper tubes. The structure is proposed for use as a low temperature radiator. The connection technology, wire spacing and diameter are not specified in more detail.

In the DE 10 2006 022 629 A1 proposes a heat exchange device for heat exchange between media with which the heat exchange device is acted upon, the media not coming into contact with one another and at least one tube being provided for a medium. The invention is characterized in that the tube is integrated in a weave structure.

In the WO 98/31976 A1 describes a heat exchanger element in which the heat transfer is achieved by means of rod fins standing perpendicularly in the flow and equally spaced from one another. The suitable cross-section is 4 mm ² and the ratio of the rod diameter / length to 0.3. In the description of the implementation, woven and knitted fabrics are mentioned as the preferred material and are described both for the wall and for the production of the rod structure. For example, the rods are also conceivable in the form of loops.

In the US 3,313,343 A describes an increase in surface area by means of a folded, unstructured, diagonally-woven metal sieve. The metal mesh is placed between two flat plates carrying the fluid, so that fluid channels are formed by the folded tissue.

In the WO 2012/141793 A1 describes a general hierarchically structured surface enlargement for heat exchangers with flat plates. The surface enlargement forms channels in the flow direction of the fluid and becomes thicker with increasing distance from the plate.

In the WO 2011/137522 A1 describes a method for producing heat exchangers from disks that have been cut from a block of layered fabric. The surfaces of these disks are sealed using coating processes so that media separation is achieved without additional separating elements (plates, foils).

A heat transfer device according to the preamble of claim 1 is for example from the GB 909 142 A known.

The technical problem underlying the present invention exists in the non-optimal adaptation of available surface enlargements to the respective question and installation situation. The demand for high heat transfer performance with small driving temperature differences and small pressure losses with little use of material in a small installation space has so far not been adequately met with the solutions known from the prior art. This is accompanied by an increased consumption of material and energy to overcome the pressure losses.

It was therefore an object of the present invention to provide devices for heat transfer which meet precisely these requirements for reduced material and energy consumption while at the same time having high heat transfer capacity and at the same time are simple and inexpensive to produce.

This object is achieved by the heat transfer device with the features of claim 1 and the heat exchanger with the features of claim 19. In claim 21 uses according to the invention are given. The further dependent claims show advantageous developments.

According to the invention, a heat transfer device is provided which has at least one channel for a heat-absorbing medium and at least one channel for a heat-emitting medium. At least one of these channels has a textile structure at least in some areas, the textile structure having compressed areas at regular intervals, the compressed areas of the textile structure in the transition area between at least one channel for a heat-absorbing medium and at least one channel for a heat-emitting medium Production of a thermal contact between these channels are arranged. Furthermore, non-compressed areas of the textile structure are arranged in the flow area of at least one channel.

Within the scope of the present invention, the term channel is also to be understood to mean those areas which are channel-shaped but, owing to the filling with a solid, e.g. PCM, no longer represent a channel or, e.g. with surface heating structures that are open to the environment.

The textile structures used according to the invention enable very large heat transfer areas. These are aligned in such a way that a large heat transfer to the heat transfer surface and a good one Heat conduction from the heat transfer surface to the separating surface is achieved. When heat transfer devices flow through, the flow is only disturbed if possible to the extent that it serves to improve the heat transfer.

The advantage of the heat transfer device according to the invention is that, with the simultaneous use of material and construction volume, less energy has to be used for the same heat transfer. With the same use of energy and construction volume, less material has to be used for the heat transfer device according to the invention, and with the same use of energy and material, the construction volume can be reduced.

A preferred embodiment provides that the channels for the heat-absorbing media are separated from the channels for the heat-dissipating media by a partition, in particular a sheet, a film, a membrane or the outer surface of a tube or hose.

It is preferred that the compressed areas in the transition area of the channels are at least partially connected to the dividing wall, in particular by gluing, soldering, welding, sintering or casting.

A further embodiment according to the invention provides that the textile structure has a coating impermeable to the media at the compressed areas.

A further embodiment according to the invention relates to a heat transfer device for separating adjacent channels in at least one channel, an expandable hose or tube which is impermeable to the media and / or is arranged around at least one channel, a shrinkable hose or tube which is impermeable to the media, which is expanded and expanded / or allow shrinking to make contact with the textile structure.

The textile structure arranged in at least one channel can preferably be flowed through by a fluid, at least in regions, in a heat-transferring manner. In a further variant, the textile structure can, at least in regions, be latently heat-storing, sorptive or catalytic fixed medium must be embedded.

A further preferred embodiment provides that the textile structures of adjacent channels have different wire lengths and / or distances between the wires in the parting plane.

The uncompressed areas can preferably be varied such that the flow resistance in the channel can be set via the wire lengths, wire diameters and / or distances between the wires. This can be used, in particular, to generate structures with an inclined flow with secondary channels lying between them. In comparison to the inflow velocity, the flow velocity through the textile structure with which the oblique structures are flowed through is reduced. When flowing around the textile structures according to the invention with small fiber, yarn or wire diameters, large heat transfers are achieved even at low flow velocities. The slower structures through which the flow flows more slowly lead to an advantageous reduced pressure loss with the same transmission density or to an advantageous higher transmission density with the same pressure loss. The area flowed towards at an angle can generally include compressed and non-compressed textile structures and, if appropriate, separate heat-transfer media which flow in the plane of this area.

Such an arrangement of the tissue structures is possible in particular if the structures are flat, i. H. be manufactured with a low flow depth. These two-dimensional structures can be folded into the desired shape in a second manufacturing process. The creation of a secondary, structure-free channel by appropriately folding the structure is not limited to textile structures. This can be replaced by other heat exchanger structures that can be flowed through, in particular lamellae, sponges, foams, sintered fiber structures or homogeneous textile structures. A comparable advantageous heat transfer behavior can thus be achieved.

The textile structure preferably consists of wires, technical fibers or yarns thereof with a preferred diameter of 10 µm to 2 µm, particularly preferably of 80 µm to 300 µm. The wires, technical fibers or yarns thereof preferably point in the direction of flow a distance of 20 µm to 20 mm, preferably from 40 µm to 10 mm and particularly preferably from 100 µm to 4 mm.

• metallischen Materialien und deren Legierungen, insbesondere Kupfer, Aluminium oder Edelstahl,
• kohlenstoffhaltigen Materialien, insbesondere Kohlefasern, Aktivkohlefasern,
• Glas- und Keramikfasern,
• Polymermaterialien, insbesondere Polypropylen (PP), Polyethylen (PE), Polyamid (PA), Polyetherketone (PEK), Polyester (PET) und
• Verbundstoffe hiervon.

The wires, technical fibers or yarns thereof are preferably selected from the group consisting of

• metallic materials and their alloys, in particular copper, aluminum or stainless steel,
• carbon-containing materials, in particular carbon fibers, activated carbon fibers,
• Glass and ceramic fibers,
• Polymer materials, especially polypropylene (PP), polyethylene (PE), polyamide (PA), polyether ketones (PEK), polyester (PET) and
• Composites thereof.

The textile structure preferably has an inherent stiffness which enables the heat exchanger to be self-supporting.

The textile structure preferably consists of a woven, knitted or knitted structure or combinations thereof.

It is further preferred that the fabric structure used has been galvanically coated with a solder and that the inherent stability of the structure and the integral connection at the nodes of the wires to one another and to the separating surface are implemented by melting the solder.

A preferred embodiment provides that lighting elements, in particular elements comprising optical fibers or LEDs, are integrated in the heat transfer device, preferably in the form of incorporated wires, fibers or yarns.

It is also possible that at least one heating wire, in particular made of copper, copper-nickel alloys, nickel-chromium alloys, constantan, manganine, nickel-iron alloys or Kanthal, is integrated in the heat transfer device.

According to the invention, a heat exchanger is also provided, which has a heat transfer device according to the invention, as described above was included. The heat exchanger is preferably a plate heat exchanger, a tube bundle heat exchanger, a tube bundle-finned heat exchanger, a flat tube-finned heat exchanger or a coaxial heat exchanger.

The heat transfer devices according to the invention are used in particular in heat transfer to / from air or other gaseous media (for example recoolers, exhaust gas heat exchangers, convectors, ventilation devices, oil coolers, etc.), in heat transfer to / from water or other liquid media, in applications with phase change ( Evaporation, condensation, solid / liquid) as well as in combination with sorption materials or catalytic coatings.

• Fig. 1 zeigt die erfindungsgemäße textile Struktur anhand zweier Ausführungsformen (Fig. 1a und 1b) im flachen wie im gefalzten Zustand.
• Fig. 2 zeigt eine erste flache Ausführungsform (Fig. 2a) und eine zweite rohrförmige Ausführungsform (Fig. 2b) der erfindungsgemäßen Wärmeübertragungsvorrichtung.
• Fig. 3 zeigt eine Variante einer erfindungsgemäßen Wärmeübertragungsvorrichtung mit einer Kombination verschiedener textiler Strukturen (Fig. 3a) und in Kombination mit einem Sammler (Fig. 3b).
• Fig. 4 zeigt eine Variante der textilen Struktur mit unterschiedlichen Drahtabständen (Fig. 4a) und Drahtlängen (Fig. 4b) im durchströmten Bereich.
• Fig. 5 zeigt eine erfindungsgemäße Variante eines Koaxialwärmeübertragers unter Nutzung der zuvor (Fig 4b) gezeigten Elemente.
• Fig. 6 zeigt eine weitere Ausführungsform einer erfindungsgemäßen textilen Struktur.
• Fig. 7 zeigt eine weitere Ausführungsform der erfindungsgemäßen textilen Struktur dargestellt.
• Fig. 8 zeigt erfindungsgemäße Beispiele für Strukturflächen.

The subject according to the invention is intended to be explained in more detail with reference to the following figures, without wishing to restrict it to the specific embodiments shown here.

• Fig. 1 shows the textile structure according to the invention using two embodiments ( 1a and 1b ) flat as well as folded.
• Fig. 2 shows a first flat embodiment ( Fig. 2a ) and a second tubular embodiment ( Fig. 2b ) the heat transfer device according to the invention.
• Fig. 3 shows a variant of a heat transfer device according to the invention with a combination of different textile structures ( Fig. 3a ) and in combination with a collector ( Fig. 3b ).
• Fig. 4 shows a variant of the textile structure with different wire distances ( Fig. 4a ) and wire lengths ( Fig. 4b ) in the flow area.
• Fig. 5 shows an inventive variant of a coaxial heat exchanger using the previously ( Fig. 4b ) shown elements.
• Fig. 6 shows a further embodiment of a textile structure according to the invention.
• Fig. 7 shows a further embodiment of the textile according to the invention Structure shown.
• Fig. 8 shows examples of structural surfaces according to the invention.

In Fig. 1 will be on the left ( Fig. 1a ) a flat fabric made of wires is shown, which has non-compacted areas (1) and more closely made wire areas (2). Folding this structure creates a spacing structure that forms a flow channel and two top surfaces. Two examples of such a spacing structure are in Fig. 1a shown in the middle part and lower part. While in the middle part of the figure the wires of the uncompressed area are arranged obliquely, in the lower part the Figure 1a the wires are arranged parallel to each other and perpendicular to the wall surface formed. In Fig. 1b A comparable embodiment is shown, but in which the more narrowly manufactured areas (2) are larger than the areas with long wire gaps (1). At the in Fig. 1c shown embodiment leads the folding to tapered secondary channels. The non-compressed areas of the textile structure located between the secondary channels are flowed through at a lower normal speed than the inflow speed, so that a lower pressure loss is achieved. The wall surfaces formed can be connected to a partition wall by one of the abovementioned joining methods or can be coated directly impermeable.

At the in Fig. 2a shown flat embodiment, the folded structure outlined above was contacted on the wall surfaces with a separating surface (3), which was designed as a sheet or foil, via solder connections (4). On the other side of the partition there is the same textile structure rotated by 90 ° so that this element can be used in a cross-flow plate heat exchanger, for example.

At the in Fig. 2b As shown in the tubular embodiment, the compressed areas of the textile structure (2) form a tubular shape, which is applied from the outside to a partition wall formed by pipes. The non-compressed areas (1) thus form the surface-enlarging structure in the area between the pipes. This structure can be flowed through, for example, perpendicular to pipes and wires in a heat-transferring manner.

As in Fig. 3a indicated, the dimensioning of the flow structures can be flexibly adapted to the corresponding media or flow conditions separated by dividing surfaces (7). It is conceivable, for example, that the dimensions of the wire spacing and heights are different for the different sides of the heat exchanger.

An application of this is with the embodiment in Fig. 3b shown. Here, one side is completely encased by the separating surface (8), so that flow-through flat tubes are formed, to which the medium is distributed via a collector (9). The other medium flows vertically through the other folded structure located between the flat tubes. As an advantage over conventional flat tubes, the stabilizing spacer structures allow the use of very thin partition walls. Due to the folding technique but also with the textile manufacturing technique, different densities of defined structural areas can also be created in one medium ( Fig. 4a ), for example to compensate for uneven velocity distributions in the incoming medium, to control temperature gradients of the second medium in a targeted manner or to deal with complex geometric requirements. As in Fig. 4b shown, the cover surfaces do not necessarily have to be parallel.

In Fig. 5 A coaxial heat exchanger with a circumferential outer shell 6 is shown, the individual segments of the tube cross section being filled with the textile structure according to the invention. Here the non-compressed areas 1 and the partition 2 on which the compressed areas are located can be seen. The segments are alternately flowed through with one or the other medium in such a way that one medium flows in and the other medium flows out of the image plane.

In terms of production technology, it is also possible to create flow structures that are generated in one production step (see Fig. 6 ), the non-compressed wires (1) can be arranged at an angle to each other. The connection to the top surface (5) can be achieved, for example, by knitting processes. The inclined position of the wires increases the inherent stability of the structure. The reduction in production steps is also attractive here, but the thermal masses must be taken into account.

In Fig. 7 an arrangement of the textile structures is shown as a heat exchanger. The area of the textile structure is exemplified by the in Fig. 2 b) given structure given. One of the heat transfer media flows first through the inflow area of the heat exchanger (10), then through the structure-free secondary channel area (11) to the textile structure (12). The medium flows through this at lower speeds than in the inflow area, since the area to be flowed through was greatly increased by the folding of the structures. The medium then flows through the structure-free channels (13) flowing out into the outflow area (14).

In Fig. 8 Various exemplary embodiments of the structural surfaces are shown. A uniformly distributed, low speed through the structure can, for example, be made possible by these different configurations (tapering ( Fig. 8a ), tapering hyperbolic ( Fig. 8b ), tapered sinusoidally ( Fig. 8c ). A uniformly distributed speed through the structure is advantageous in order to optimally use all areas of the structure for heat transfer. Depending on the arrangement, fewer and more densely compressed areas in the structure along the fabric structure ( Fig. 7 , (12)) vary and further promote equal distribution.

In Fig. 8d An embodiment is shown with several folded structures connected in series. This allows a further increase in the heat exchanger area in a small installation space and thus an increase in the power density with a small increase in the pressure loss.

Claims (15)

1. Heat transfer device comprising at least one channel for a heat-absorbing medium and at least one channel for a heat-emitting medium, at least one of the channels having a textile structure, at least in regions,
   characterized in that
   the textile structure having regions compressed at regular spacings, the compressed regions of the textile structure being disposed in the transition region between at least one channel for a heat-absorbing medium and at least one channel for a heat-emitting medium for the production of a thermal contact and the non-compressed regions of the textile structure being disposed in the flow region of at least one channel.
2. Heat transfer device according to claim 1,
   characterised in that the channels for the heat-absorbing media are separated from the channels for the heat-emitting media by a separating wall, in particular a metal sheet, a foil, a membrane or an outer surface of a tube or hose.
3. Heat transfer device according to the preceding claim, characterised in that the compressed regions in the transition region of the channels are connected integrally to the separating wall, at least in regions, in particular by gluing, soldering, welding, sintering or casting.
4. Heat transfer device according to one of the preceding claims, characterised in that, for separation of adjacent channels, in at least one channel, an expandable hose or tube which is impermeable for the media is integrated and/or, around at least one channel, a shrinkable hose or tube which is impermeable for the media is disposed, which enable contacting to the textile structure by widening and/or shrinking.
5. Heat transfer device according to one of the preceding claims, characterised in that the textile structure is permeated, at least in regions, by a fluid for heat exchange and/or the textile structure is embedded, at least in regions, in a latently heat-storing, sorptive or catalytic stationary medium or is coated therewith on the surface, wherein the textile structures of flow channels adjacent to each other have different wire lengths and/or spacings of the wires in the flow direction.
6. Heat transfer device according to one of the preceding claims, characterised in that the spacings of the compressed regions are varied such that the flow resistance in the flow channel is adjustable via the wire lengths, wire diameters and/or spacings of the wires.
7. Heat transfer device according to one of the preceding claims, characterised in that the textile structure is configured to be planar and has a fold and preferably comprises channels for at least one medium in the plane of the surface, the surface of the textile structure to be permeated by at least one medium being increased relative to the inflow surface, as a result of which the flow rate through the textile structure of the at least one medium is reduced.
8. Heat transfer device according to one of the preceding claims, characterised in that the wires, technical fibres or yarns hereof have a diameter of 10 µm to 2 mm, preferably of 80 µm to 300 µm and/or have, in flow direction, a spacing of 20 µm to 20 mm, preferably of 40 µm to 10 mm, and particularly preferably of 100 µm to 4 mm.
9. Heat transfer device according to one of the preceding claims, characterised in that the wires, technical fibres or yarns hereof are selected from the group consisting of

   • metallic materials and the alloys thereof, in particular copper, aluminium or stainless steel,

   • carbon-containing materials, in particular carbon fibres, activated carbon fibres,

   • glass- or ceramic fibres,

   • polymer materials, in particular polypropylene (PP), polyethylene (PE), polyamide (PA), polyether ketones (PEK), polyester (PET) and

   • composite materials hereof.
10. Heat transfer device according to one of the preceding claims, characterised in that the textile structure has an intrinsic rigidity which enables a self-supporting construction of the heat exchanger.
11. Heat transfer device according to one of the preceding claims, characterised in that the textile structure is a woven, knitted or warp-knitted structure or a combination hereof.
12. Heat transfer device according to one of the preceding claims, characterised in that the fabric structure used was coated galvanically and, by melting the solder, the intrinsic stability of the structure and the integral connection at the node points of the wires is implemented to each other and to the separating foil.
13. Heat transfer device according to one of the preceding claims, characterised in that, in the heat transfer device, lighting elements, in particular optical fibres or elements having LEDs, preferably in the form of incorporated wires, fibres or yarns, and/or at least one heating wire, in particular made of copper, copper-nickel alloys, nickel-chromium alloys, constantan, manganin, nickel-iron alloys, kanthal, are integrated.
14. Heat exchanger in particular a plate heat exchanger, a tubular heat exchanger, a tubular lamellar heat exchanger, a flat tube lamellar heat exchanger or a coaxial heat exchanger comprising a heat transfer device according to one of the preceding claims.
15. Use of the heat transfer device according to one of the claims 1 to 13 in heat transfer to air or other gaseous media, in particular in recirculation coolers, exhaust gas heat exchangers, convectors, ventilation devices or oil coolers, in heat transfer to water or other liquid media, in applications with phase change (evaporation, condensation, solid/liquid) and chemical reactions and also in combination with sorption materials or catalytic coatings.

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