HEAT EXCHANGER

Abstract

A heat exchanger is provided, in particular for a motor vehicle, with at least one thermoelectric element to generate a heat flow, wherein the thermoelectric element is arranged on a carrier element, wherein several carrier elements arranged on top of one another along a stacking spindle form a carrier element stack, in which a first fluid channel for a first fluid and a second fluid channel for a second fluid, fluidically separated from the first, are constructed.

Description

This nonprovisional application claims priority under 35 U.S.C. §119(a) to German Patent Application No. 10 2013 222 130.4, which was filed in Germany on Oct. 30, 2013, and which is herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a heat exchanger, in particular for a motor vehicle, particularly for the temperature control of at least one energy storage element.

2. Description of the Background Art

When utilizing modern, strictly electrically operated motor vehicles, only a limited amount of energy is available due to the low storage density of the batteries. Therefore, energy efficiency, particularly with respect to the heating and cooling functions in the motor vehicle, plays an important role especially within the scope of the advancing electrification of motor vehicles. If, for example, energy is required for the heating of the motor vehicle's interior in the winter, this can result in a corresponding reduction of the cruising range of the motor vehicle, for example. Therefore, concepts are meaningful wherein the available electric energy from the battery can not only be converted to 100% heat, but due to the utilization of a heat pump in a heat pump process an even higher coefficient of performance (COP) than “1” can be achieved, or a higher COP can be achieved through the utilization of residual heat from the vehicle or from the environment.

In an effective thermo management in the vehicle, for example for cooling purposes of the motor or other assemblies or for heating purposes, a coolant is used which circulates as a fluid in the cooling system of the vehicle. For an electric cooling function thermoelectric elements, for example, Peltier elements, are known, wherein heat can be pumped with a coefficient of performance greater than “1” with the thermoelectric elements when heating is desired.

A heat pump features a heat exchanger which, via a thermoelectric element (TE element), can make waste heat and/or residual heat available from a first fluid flow to a higher temperature level in a second fluid flow as available heat energy. The available heat energy can then, be utilized for a heating element, for example, and thus for the heating of the vehicle's interior.

When utilizing modern high performance batteries which are constructed of a number of individual cells, such as for example in electro or hybrid vehicles, it is sensible that the temperature of the high performance battery is within a certain temperature interval during the operation of the motor vehicle to ensure the efficiency, serviceability and safety of the battery and/or the motor vehicle. On one hand, the efficiency of the battery cells drops considerably when a service temperature drops below a suitable limit and the cells produce a high power loss. On the other hand, processes take place within the cells above a suitable operating range, leading to irreversible damage. In addition, to avoid an irregular and coinciding increased aging of individual battery cells, the temperature differences within the individual cells as well as in the entire battery assembly may not exceed certain predetermined threshold values. For these reasons a battery tempering in the form of cooling or heating is necessary.

A heat exchanger with two fluid sides is known, which allows for the realization of two independent circuits to temper different components of a motor vehicle. The design of such a heat exchanger comprises a layered construction with the two fluid sides in contact with one another via thermoelectric elements. DE 10 2009 058 673 A1, which corresponds to US 20120312029, which is incorporated herein by reference, for example, describes such thermoelectric elements, wherein during the flow feed of the thermoelectric elements heat is pumped from one fluid to the other fluid without the fluids touching or mixing. In doing so, one fluid side is part of a fluid circuit to temper components, for example of a battery or a high voltage battery of a motor vehicle. The other fluid side is part of a fluid circuit to temper at least one other component and/or for the heat transfer between fluid circuit and environment.

Other heat exchangers are known and utilized in counter flow construction, wherein the coolant flows are primarily run in closed metallic components, for example plates, metal sheets. Here, the heat from the plates can be transferred to the thermoelectric elements through a heat conductive contact, for example, an adhesive. First, the metallic components are assembled from individual parts, and a fluid tight connection is produced through a soldering process. This can be done advantageously prior to the thermoelectric elements coming into contact with the components. This soldering process to connect the individual components is cost-intensive and can lead to leakages in the component system when done improperly.

SUMMARY OF THE INVENTION

It is the object of the invention to create an improved heat exchanger which allows a tailor-made cooling and heating of components and/or can be utilized as a heat pump.

An embodiment of the invention provides a heat exchanger, particularly for a motor vehicle, with at least one thermoelectric element to generate a thermal flow, wherein the at least one thermoelectric element is arranged on a carrier element, wherein several carrier elements arranged along a stacking spindle on top of one another form a carrier element stack, in which a first fluid channel for a first fluid and a second fluid channel for a second fluid, designed separately from the first fluid channel, are provided.

The first fluid channel can be part of a first fluid circuit and can serve for the tempering of an external component or the thermoelectric element. The second fluid channel is preferably part of a second fluid circuit, fluidically separate from the first fluid circuit. Typically, the first and the second fluid circuit run parallel to the stacking spindle of the carrier element stack of the heat exchanger. The heat flow can be generated, for example, by diverting the heat from the thermoelectric element via the first fluid, wherein the first fluid is at least in part flowing around certain areas of the thermoelectric element. Preferably, a surface of the thermoelectric element is circulated around or approached by the first fluid.

The carrier elements can be of identical construction and are thus repeat parts that can be manufactured cost-effectively. The carrier elements can be constructed as relatively flat building components, wherein a level of the carrier element provided parallel to the stacking spindle is smaller than the dimensions of the areal dimensions in a carrier element level which primarily runs vertically to the stacking spindle and is arranged within an outside boundary line. The carrier element level with the greatest building component dimension can have a structure featuring windows, for example braces, bridges etc. can be provided. The carrier elements can be manufactured as injection molding parts. This is advantageous since the structure of the carrier element stack is easily scaleable, can be of modular construction and with that, a cost-efficient production of the heat exchanger becomes possible. Therefore a modularly built compact heat exchanger can be produced in an easy installation, whereby no soldering process to connect the individual components may be necessary.

The heat exchanger can have a bottom element and a cover element which complete the carrier element stack. Here, the carrier element stack can be closed on both sides lengthwise along the stacking spindle. Here, the cover element and/or the bottom element can be an upper carrier element or a lower carrier element and be designed on the basis of the carrier element supporting the thermoelectric element. Preferably, connections particularly coupling flanges or connecting pieces for the first fluid circuit and/or the second fluid circuit can be provided here. The cover element and/or the bottom element are essentially identical or similar to the other carrier elements, but they can also have a different construction and/or another structure than the carrier elements.

The carrier element can be made of a synthetic material with a synthetic material frame wherein the first fluid channel and the second fluid channel are provided. At least one thermoelectric element is provided on the synthetic material carrier element, preferably in the center. However, several thermoelectric elements can also be provided in series on a carrier element, in particular the synthetic material carrier element. The synthetic material carrier element is a repeat park and by stacking can easily be assembled as the carrier element stack.

In an embodiment the carrier element can have a primarily polygon outside boundary line. In a most basic embodiment the carrier element is square and has an essentially square surface area with four sides, forming four outside boundary lines. Here the corners between the sidelines are either shaped at an acute angle or they are rounded. In one special embodiment the carrier element has an octagonal surface area, and the outside boundary line has eight lateral faces. Here the lateral faces can have different lengths.

The carrier element can have isolation devices which can separate the first fluid channel and the second fluid channel. Preferably, the isolation device causes a thermal isolation between the first and the second fluid channel. For example, the isolation device can be a bridge made of a non-heat conductive material. Preferably, the isolation device is designed as one piece with the carrier element and has a bridge or a combination of bridges made of the synthetic material of the carrier element.

The first and the second fluid channel each can have a first and a second partial fluid channel, wherein the first and the second partial fluid channel each are connectable via at least one overflow opening in the carrier element. The first partial fluid channel and the second partial fluid channel preferably run here at least in sections parallel to the stacking spindle. The first partial [fluid] channel and the second partial fluid channel of the first fluid channel are preferably arranged opposite on the carrier element, so that a partial flow via the thermoelectric element can occur in a line vertical to the stacking spindle. Preferably, at least one overflow opening is provided here through which the first fluid from the first partial fluid channel of the first fluid channel can exit and flow vertical to the stacking spindle over the thermoelectric element, and at least one second overflow opening allowing an entry into the second partial fluid channel of the first fluid channel. The first and the second partial fluid channel of the second fluid channel can be connected via a connection channel with a fluidic separation from the flow path of the first fluid channel.

Connecting elements can be provided on the bottom element and/or the cover element to connect the first and/or the second fluid channel with the first and/or the second fluid circuit. Here the fluid circuit can be part of a cooling system of the motor vehicle, but it can also be designed as a separate cooling circuit detached from it.

In an embodiment of the heat exchanger, the carrier elements can be installed in such a manner that they are centrically stackable around a stacking spindle. Preferably, at least one thermoelectric element is arranged centrically in relation to the stacking spindle.

A fluid tight connection can be provided between the carrier elements and the thermoelectric elements. This can be realized in particular via mechanical connection methods, for example through clipping, latching, welding, gluing or casting.

In an embodiment the carrier elements stacked on top of one another can be aligned or they can be arranged with a rotation of 90° each to a stacking spindle. The carrier elements, particularly the adjoining carrier elements can be arranged relative to one another rotated by 90°, 180° or 270° in the level vertical to the stacking spindle. Here, the carrier elements can be connected fluid tight to one another as well as the carrier elements with the thermoelectric element.

Flat tubes can be provided which are in thermal contact with the thermoelectric elements, preferably in direct thermal contact with them. The flat tubes can be connected fluid tight with the carrier element. The thermal contact is preferably arranged via a conductive adhesive provided between an external wall of the flat tubes and the thermoelectric element. Here it is advantageous that the first fluid is not directly in contact with the thermoelectric elements.

The carrier element can be manufactured from one material, for example from one single synthetic material. Alternatively, the carrier element can have several material elements in addition to the one carrier material. Here the carrier element can be manufactured from the synthetic material through injection molding. Metallic elements can also be embedded in the synthetic material of the carrier element. The electric connections of the thermoelectric element can hereby be realized through the metallic elements. The carrier element can be reinforced mechanically by embedding glass fibers and/or carbon fibers.

The thermoelectric element can be designed as a Peltier element. The thermoelectric element is preferably material-bonded with the carrier element, for example glued. The thermoelectric element can also be in a frictional connection with the carrier element, such as for example press-fitted.

During heating, the Peltier elements can serve as a heat pump to heat the components to be tempered, while during cooling the Peltier elements can provide a cooling of a corresponding component. A tempering can be realized by different current feeds of the Peltier elements in the heat exchanger, with the possible reversal of the flow direction.

On its external wall the carrier element stack can be enclosed by a special section tube, wherein the special section tube indicates the outside profile of the carrier stack, which forms the internal contour of the tube. It is advantageous here that an increased security is provided with respect to fluid tightness. For example, the special section tube can be connected fluid tight with the carrier element stack through laser welding.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

FIG. 1 is a schematic illustration of a heat exchanger with carrier elements in a side view;

FIG. 2 is a schematic illustration of a carrier element with a thermoelectric element as a top view;

FIG. 3 is a carrier element of the heat exchanger in perspective illustration as a top view;

FIG. 4 illustrates an embodiment of a heat exchanger according to the invention having stacked carrier elements according to FIG. 3 as a perspective view from the top;

FIG. 5 is another embodiment of a carrier element in a perspective top view;

FIG. 6 is a carrier element according to FIG. 5 without a thermoelectric element;

FIG. 7 is a carrier element stack having carrier elements according to FIG. 5 and FIG. 6 of a heat exchanger in a perspective top view;

FIG. 8 is another embodiment of a stack layer with one carrier element in a perspective top view;

FIG. 9 is a carrier element unit of the carrier element of FIG. 8 in a perspective top view; and

FIG. 10 is a carrier element stack of a heat exchanger according to the invention with synthetic material frame and thermoelectric elements in a perspective top view.

DETAILED DESCRIPTION

FIG. 1 shows a heat exchanger 10 in a schematic side view having a stack 12 of stacking disks 14 and fluid channels 16 for a first fluid and fluid channels 18 for a second fluid.

The flow paths of the fluid are each identified with the arrows 17 (fluid 1) and 19 (fluid 2). Fluid channel 16 and fluid channel 18 are fluidically separated and carry a fluid each (fluid 1 and fluid 2) with the flow paths 17 and 19 separated. In addition, connections 20 and 22 are provided for the fluid channels 16 as well as connections 24 and 26 for the fluid channels 18. Stack 12 has thermoelectric elements 28 (shown in FIG. 2).

FIG. 2 shows the heat exchanger 10 in a top view. Same objects are identified with the same reference numerals. The thermoelectric element 28 covers most of the surface of the area of stack 14, which also has the fluid channels 16 and 18.

The heat exchanger 10 can also be referred to as a water conditioner for one exemplary embodiment. It is constructed in accordance with the principle of the cross-flow heat exchanger. Here the first fluid channel 16 and the second fluid channel 18 cross at least in certain areas. The heat exchanger 10 can also be referred to as a recuperator in another embodiment.

The thermoelectric element 28 is arranged on a carrier element 30 and is preferably connected with it, at least mechanically. The thermoelectric element 28 is preferably arranged in the center of the carrier element 30. However, more than one thermoelectric element 28 can also be arranged on the carrier element 30, which are then arranged next to one another and are switched in series. Fluid channels 16 and 18 are each arranged at a margin 32 of the carrier element 30.

FIG. 3 shows a perspective top view of the carrier element 30 with the thermoelectric element 28 in a first embodiment. The carrier element 30 has a frame 34 which represents an outer boundary and, with that, an outer boundary line 36 of the carrier element 30. The outer boundary line 36 is square in the carrier element 30 of this embodiment and has four branch lines 36a, 36b, 36c, 36d. The respective adjoining branch lines 36a, 36b, 36c, 36d are connected and form a connecting component 38a, 38b, 38c, 38d, so that the outer boundary line or external contour 36 is configured as one piece. The connecting component 38a, 38b, 38c, 38d can have a rounded contour (in this example) or an angular contour. Starting from the corner element 38a, 38b, 38c, 38d an isolation device 40a, 40b, 40c, 40d is provided that allows the thermal and fluidic separation of the respective adjoining fluid channels 16 and 18. Starting from the branch line 36a, 36b, 36c and/or 36d at least one bridge 44a, 44b, 44c, 44d is provided to increase the inherent rigidity of the [text missing]. This increases the stability of the carrier element.

Parallel to the outer boundary line 36 a second contour line, an interior contour line 46, is provided at a distance from it. Here the bridges 44a, 44b, 44c and 44d and/or the isolation devices 40a, 40b, 40c and 40d are provided between the outer boundary contour 36 and the interior contour 46. Contours 36 and 46 are arranged at a distance to one another in accordance with the location of the connecting bridges 44. The thermoelectric element 28 is essentially arranged in the center within the interior contour 46. The thermoelectric element 28 is a first thermoelectric element 28a in the embodiment in FIG. 2, and a second thermoelectric element 28b can be provided below the first thermoelectric element 28a, whereby a flat tube 48 is provided between the two thermoelectric elements 28a and 28b. Preferably, the flat tube 48 is thermally connected with the first and the second thermoelectric element 28a and 28b. Flat tube 48 in each stack level connects the two sides of the fluid channel 18 for the second fluid. The first fluid can flow through openings in the interior contour 46 through the flat tube 48 and enter the fluid channel 16.

FIG. 4 shows a carrier element stack 12 of the heat exchanger 10 constructed of carrier elements 30 according to FIG. 3. The carrier element stack 12 features the carrier elements 30 which are constructed along a stacking spindle 50 with individual layered stacks 14 from the carrier element 30 according to the first exemplary embodiment per FIG. 3. For clarity reasons only the carrier element stack 12 of the heat exchanger 10 is shown in FIG. 3 and not the bottom element or the cover element. Stack 12 shows the carrier elements 30 from FIG. 3 as layered stack, arranged stacked on top of one another along the stacking spindle 50, so that fluid channel 16 and fluid channel 18 can stretch along the direction of the longitudinal extension and primarily parallel to the center axis 50. Fluid channel 16 and fluid channel 18 run primarily parallel to one another. The thermoelectric element 28 designed as a Peltier element is arranged on carrier element 30, preferably in the center, so that fluid channels 16 and 18 are arranged around the thermoelectric element 28. Respective adjoining carrier elements 30 are each arranged around the stacking spindle 50 rotated by 90° towards one another. The carrier elements 30 are connected fluid tight among one another, for example through presssing or gluing or another suitable connection method, so that the fluid channels 16 and 18 are fluid tight in the direction of the stacking spindle 50. Towards one another the fluid channels 16 and 18 are thermally isolated over the entire longitudinal extension of the carrier element 14 through isolation devices 40a, 40b, 40c and 40d.

FIG. 5 shows a carrier element 52 in another embodiment. Identical objects are identified with the same reference numerals. The carrier element 30 has the carrier element segments 54a, 54b, 54c, 54d arranged within the outer contour

line 36, which essentially has the same shape as the one of carrier elements 30, through each of which one of the fluid channels 16 and 18 runs. Thermoelectric element 28 is arranged concentric to the stacking spindle 50, and the carrier elements 54a, 54b, 54c and 54d are arranged around thermoelectric element 28 and within the outer contour line 36.

Thermoelectric element 28 is arranged on a lattice element 60 of the carrier element 52 shown in FIG. 6, having ribs, bridges 62, forming a turbulent lattice 64. The ribs and bridges 62 form a kind of hollow structure in the carrier element 60 through which the fluid can flow and can flow along a surface of the thermoelectric element 28 and thus discharge the generated heat. Isolation devices 40a, 40b, 40c and 40d are provided between the carrier element segments 54a, 54b, 54c and 54d.

FIG. 7 shows a carrier element stack 12 having eight carrier elements 52 without bottom element and without cover element. The thermoelectric elements 28 of the adjoining carrier elements 52 are arranged on top of one another. Isolation devices 40a, 40b, 40c and 40d are provided between each of the carrier element segments 54a, 54b, 54c and 54d.

FIG. 8 shows in a schematic perspective illustration a carrier element 65 in another embodiment. Carrier element 65 has two parts with a first upper carrier element unit 64a and a second lower carrier element unit 64b, shown again individually in FIG. 9. Carrier element unit 64a has a two part carrier element segment 64 that includes the first fluid channel 16, arranged on both sides around a central carrier element segment. The central carrier element segment 68 has ribs and bridges 70 forming the turbulent lattice 64. The thermoelectric element 28 is arranged on the ribs and bridges 70 such that it is placed between the first and the second carrier element unit 64a and 64b. Connections 72, especially electric connections 72 to the thermoelectric element 28 are led to the outside between the first and the second carrier element unit 64a and 64b, and the thermoelectric element can be electrically contacted via the connections 72.

The second carrier element unit 64b shown in FIG. 9 has two second carrier element segments 74 in addition to the two piece carrier element segment 66, through which the second fluid channel 18 is run. The carrier element segment does not have any bridges. The illustrations of FIGS. 8 and 9 of the carrier element units 64a and 64b show the overflow channels 76 between the central carrier element 68 and the carrier element segments 66, each arranged on the two sides of the central carrier element segment 68. Between the carrier element segment 66 and the carrier element segment 74 isolation devices 78 are arranged that can perform a thermal and mechanical separation of the fluid channels 16 and 18, especially when the carrier element 52 is manufactured from a thermally non-conductive synthetic material. Isolation devices 78 are formed as recesses in the carrier element 64.

In a schematic perspective illustration FIG. 10 shows a carrier element stack 80 which is constructed of carrier element units 64a and 64b, whereby the carrier element units 64a and 64b are alternately stacked on top of one another, wherein one layered stack 82 is constructed in two parts each of the carrier element units 64a and 64b.

All embodiments of the carrier element 30, 52, 65 have in common that a frame structure is formed, preferably a synthetic material frame, on which the thermoelectric element 28, 28a, 28b is arranged. The synthetic material frame is preferably manufactured by an injection molding technique and is made of one piece. The construction of the carrier element stack 12 of the carrier elements 30,53 or 64 is aligned towards the stacking spindle 50 that runs vertically to a layer level of the carrier elements 30, 52, 65 and realizes a modularly constructed cross-flow heat exchanger 10 with collecting ducts, each formed by the fluid channels 16 and 18. The carrier element stack 12 is closed by a bottom element and a cover element (not shown), which represents the hookups 20, 22, 24, 26 to the connection with the respective fluid circuit. A fluid tight connection can be produced between the respective carrier elements 30, 52, 64a, 64b or 65 through a basically known connection method with sealing elements, through a snap-on or clip connection, through gluing, pressing or pouring as well as welding.

In addition, similar to the embodiment shown in FIG. 3, flat tubes can be arranged in direct contact on the heat conductive surface of the thermoelectric element 28, 28a, 28b and be connected fluid tight with the carrier element 30, 52, 64a, 64b or 65. The flat tubes 48 are preferably made of aluminum or an aluminum alloy and can be manufactured by extrusion. Preferably, a heat conductive catalyst, such as an adhesive, is provided between the flat tubes.

The carrier element 30, 52, 64a, 64b or 64 can be made of a simple synthetic material compound or of a synthetic material a with carbon fibers or glass fibers embedded in a substrate. The metal parts required for the electric connections can also be embedded in the carrier element 30, 52 or 64, so that the carrier element 30, 52 or 64 includes a synthetic material frame with metal elements, whereby the carrier element 30, 52 or 64 is constructed as one piece.

In addition, the carrier element 30, 52, 64a, 64b or 65 of the carrier element stack 12 can be surrounded by a special section tube around the outer contour line 36, providing greater safety and stability of the stack 12. Here the special section tube is preferably attached to the synthetic material frame through welding.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.

Claims

1. A heat exchanger for a motor vehicle, the heat exchanger comprising:

a carrier element;

at least one thermoelectric element to generate a heat flow, the thermoelectric element being arranged on the carrier element, wherein a plurality of carrier elements arranged on top of one another along a stacking spindle form a carrier element stack;

a first fluid channel for a first fluid; and

a second fluid channel for a second fluid, the second channel being fluidically separated from the first fluid channel.

2. The heat exchanger according to claim 1, wherein a bottom element and a cover element are provided that close the carrier element stack at an end thereof.

3. The heat exchanger according to claim 1, wherein the carrier element has a synthetic material frame in which the first fluid channel and the second fluid channel are formed.

4. The heat exchanger according to claim 1, wherein the carrier elements have an essentially polygon, a rectangular, or octagonal outer boundary line.

5. The heat exchanger according to claim 1, wherein the carrier element is constructed as a flat building component, wherein a level formed parallel to the stacking spindle of the carrier element is smaller than a dimension of the flat extension in a carrier element level.

6. The heat exchanger according to claim 1, wherein the carrier element has a plurality of windows formed by an arrangement of braces or bridges.

7. The heat exchanger according to claim 1, wherein isolation devices are provided in the carrier element, which thermally and mechanically each separate the first fluid channel and the second fluid channel from one another.

8. The heat exchanger according to claim 1, wherein the first fluid channel and the second fluid channel each have a first and a second partial fluid channel, and wherein each of the first and the second partial fluid channel are connectable to one another by at least one overflow opening in the carrier element.

9. The heat exchanger according to claim 1, further comprising connecting elements to connect the first and/or the second fluid channel with a first and/or a second fluid circuit, the connecting elements being arranged on a bottom element and/or on a cover element.

10. The heat exchanger according to claim 1, wherein the thermoelectric element is a Peltier element.

11. The heat exchanger according to claim 1, wherein the thermoelectric element has a friction-locked or substance-bonded connection with the carrier element or wherein the thermoelectric element is pressed or glued with the carrier element.

12. The heat exchanger according to claim 1, wherein a fluid tight connection is provided between the carrier elements of the carrier element stack and/or the carrier element and the thermoelectric element.

13. The heat exchanger according to claim 1, wherein the carrier elements stacked on top of one another are facing a same direction or are each arranged at a rotation of about 90° to a stacking spindle.

14. The heat exchanger according to claim 1, further comprising flat tubes that are in contact with the thermoelectric elements and are connected fluid tight with the carrier element.

15. The heat exchanger according to claim 1, wherein the carrier element is formed of a material, which includes synthetic material and/or several material elements.

16. The heat exchanger according to claim 1, wherein the carrier element stack is enclosed by a special section tube.