EP2395296A1 - Heat exchanger - Google Patents

Abstract

The heat exchanger (1) has an electrical resistance heating element (2), particularly positive temperature coefficient element. A conducting element (11) is provided for transferring heat from the electrical resistance heating element to a fluid. An electrical insulating element (22) is provided with two conductors (4). An independent claim is also included for a method for manufacturing a heat exchanger.

Description

The invention relates to a heat exchanger according to the preamble of claim 1, an automotive air conditioning system according to the preamble of claim 10 and a method for producing a heat exchanger or an automotive air conditioning system according to the preamble of claim 11.

Automotive air conditioning systems serve to heat and / or to cool the air to be supplied to the interior of a motor vehicle. In automotive air conditioning systems, heat exchangers are used as electrical heaters to heat the air supplied to the interior. The electric heater includes PTC elements. Positive Temperature Coefficient (PTC) elements are current-carrying materials that have electrical resistance and can conduct electricity better at lower temperatures than at higher temperatures. Their electrical resistance thus increases with increasing temperature. The PTC element is generally made of ceramic and is a PTC thermistor. This raises regardless of the boundary conditions - such. B. applied voltage, nominal resistance or air flow to the PTC element - a very uniform surface temperature at the PTC element. Overheating can be prevented as it z. B. could occur with a normal heat-emitting heating wire, since regardless of the boundary conditions always about the same resistance and thus a substantially identical electrical heating power is applied.

The heat exchanger comprises PTC elements, at least two electrical conductors by means of which electrical current is conducted through the PTC element and heat conducting elements, in particular fins or corrugated fins, by means of which the surface for heating the air is increased. Increasingly, motor vehicles are produced which have an exclusive electric drive or a hybrid drive. Automotive air conditioning systems for these motor vehicles generally no longer have a heat exchanger for heating the air through which cooling fluid flows. The entire heating power of the motor vehicle air conditioning system must therefore be applied by the electric heater or the PTC elements. For this reason, it is necessary, the PTC elements with high voltage, z. B. in the range of 50 to 600 volts instead of low voltage with 12 volts to operate. High voltage in an automotive air conditioning system, however, is a security problem because, for example, by a human touch of high voltage parts of the person from the high voltage health damage can be added.

The US 4,327,282 shows a heat exchanger with a PTC heating element. Power is passed through the PTC heater via contact plates and an insulating layer on the contact plates arranged. The components are held together by means of a U-shaped clip.

From the EP 1 768 458 A1 a heat generating element of a heater for air heating is known, comprising at least one PTC element and voltage applied to opposite side surfaces of the PTC element electrical conductor tracks, wherein the two electrical conductors are surrounded on the outside by a non-electrically conductive insulating layer.

The object of the present invention is therefore to provide a heat exchanger and an automotive air conditioning system and a method for producing a heat exchanger and an automotive air conditioning system, in which a with electric current under high voltage, for. B. more than 50 V, operated heat exchanger without endangering the environment, especially people, can be operated. The heat exchanger and the vehicle air conditioning should be inexpensive to manufacture reliable in operation

This object is achieved with a heat exchanger comprising at least one electrical resistance heating element, in particular at least one PTC element, at least two conductors electrically connected to the at least one electrical resistance heating element, in particular printed circuit boards, in order to conduct electrical current through the at least one electrical resistance heating element and thereby to heat the electrical resistance heating element, at least one heat conducting element for transmitting heat from the at least one electrical resistance heating element to a fluid to be heated, at least one electrical insulating element electrically isolating the at least two conductors, preferably from the at least one heat conducting element, the at least two conductors and / or the at least one electrical resistance heating element are arranged in at least one of at least one cavity wall limited cavity and the at least one electrical insulating element is at least one molded seal, wherein the at least one cavity wall is formed as at least one closed tube without a joint in cross section. The tube is thus easy to manufacture and can only be produced by means of extrusion molding and already has a closed cross-section after production in cross-section. As a result, it is no longer necessary, the walls of the at least one tube to a closed tube with each other subsequently at a joint, z. As a welding, soldering or splice to connect.

In particular, the at least one tube is designed as at least one flat tube with two broad side walls and two narrow side walls and the two narrow side walls are braced by means of a force acting on the two broad side walls compressive force, in particular the two narrow side walls are braced at a bending edge or a bending circle. On the two broad side walls of the at least one tube thus acts a compressive force, so that thereby the two broad side walls are pressed onto a heating composite in a cavity enclosed by the at least one tube. As a result, the heating system is non-positively, in particular by means of clamping or jamming, connected to the at least one tube, in particular the Breitseitenwandungen.

In a further embodiment, the at least one heat-conducting element comprises at least one tube and / or the at least one heat-conducting element comprises corrugated ribs which are arranged on the outside of the at least one tube, in particular by means of soldering or gluing, and / or the at least two conductors have no direct contact to the at least one tube.

In a supplementary embodiment, the at least one heat-conducting element, in particular the at least one tube and / or the corrugated ribs, at least partially, in particular completely, of metal, for example aluminum or steel, or plastic

Preferably, the at least one molded gasket is disposed between each of a wall of the at least one tube and a conductor, so that the at least two conductors are electrically insulated with respect to the at least one tube.

In one variant, two, preferably substantially rectangular, shaped seals are arranged in the cavity, or the at least one molded seal is formed in the cavity as a tube, in particular a shrink tube. The two substantially rectangular shaped seals are clamped between in each case a broad side wall of the at least one flat tube and in each case a printed circuit board. The hose, in particular as a shrink tube, which forms the molded seal encloses the heating unit with the two printed circuit boards and the PTC elements. As a result, the heating unit is electrically insulated.

Suitably, the at least one molded seal is elastic and / or the at least one molded seal consists at least partially of silicone or plastic or rubber and / or the at least one molded seal is positively and / or positively and / or materially connected to the at least one tube and / or the at least one molded seal is a foil. On a heat exchanger with multiple heating registers, a compressive force is applied and the elastic molded seal can deform due to this compressive force.

In a further embodiment, the at least one molded seal comprises heat-transmitting or thermally conductive particles, for. For example, alumina and / or silicon carbide and / or boron nitride, and / or the at least one tube is from a first, z. B. upper, cover plate at a first end, in particular fluid-tight, closed and / or the at least one tube is of a second, z. B. lower, cover plate is closed at a second end, in particular fluid-tight. Heat-transferring or heat-conducting particles in the at least one molded seal ensure that the heat generated by the PTC elements can also be conducted outwards to the heat-conducting elements, in particular the at least one tube and / or the corrugated fins, in a sufficiently good thermal conductivity.

In particular, the at least one electrical resistance heating element, the at least two conductors and the at least one molded seal are connected to at least one heating composite, which is or are arranged within the at least one tube, and preferably a plurality of tubes each having a heating composite and arranged between the tubes corrugated fins form the heat exchanger, wherein in particular by means of a clamping frame or a spring on the walls of the at least one tube, in particular the broad side walls of the at least one flat tube, the compressive force is applied.

An automotive air conditioning system according to the invention comprises at least one heat exchanger described in this patent application.

Method according to the invention for producing a heat exchanger or an automotive air conditioning system, in particular a heat exchanger described in this patent application or a Kraffifahrzeugklimaanlage described in this patent application, with the steps: provide at least one electrical resistance heating element, in particular at least one PTC element available providing at least two electrical conductors, in particular printed circuit boards, for passing electrical current through the at least one electrical resistance heating element, providing at least one heat conducting element for transmitting heat from the at least one electrical resistance heating element to a fluid to be heated, providing at least one electrical Insulating element as a molded seal for electrically insulating the at least one heat conducting element of the at least two conductors, connecting the at least two conductors to the at least one electrical resistance heating element, thermally connecting the at least one heat conducting element to the at least one conductor and / or to the at least one electrical resistance heating element, electrical Isolating the at least two conductors, preferably of the at least one heat conducting element, by means of the at least one molded seal, in that the at least two conductors are connected to the one or more conductors at least one electrical resistance heating element and the at least one molded gasket are connected to at least one heating composite, wherein the at least one heat conducting element comprises at least one cavity wall which encloses at least one cavity and the at least one cavity wall is formed by at least one tube, wherein the tube, in particular by means of extrusion, is produced with a closed cross-section without joint

In a further embodiment, the at least one tube is produced as at least one flat tube and the at least one heating composite is introduced into the at least one cavity, which is enclosed by the at least one flat tube closed in cross section, and then the flat tube is deformed on the narrow side walls and thus also braced, so that the broad side walls of the flat tube is pressed onto the at least one molded seal.

In a supplementary variant, during the introduction of the at least one heating composite into the at least one cavity, the thickness of the at least one cavity between the two broad side walls is greater than the thickness of the heating composite between the at least one molded seal on the at least two conductors. The thickness of the heating composite is preferably determined perpendicular to a plane spanned by the printed circuit boards.

In a further variant, after introducing the at least one heating composite into the at least one cavity, the shape of the at least one cavity wall is changed, in particular bent, so that the volume of the at least one cavity is reduced and preferably thereby the heating composite is frictionally engaged with the broad side walls of the at least one cavity Flat tube is connected.

In a further embodiment, the at least one molded seal is formed as a shrink tube and the shrink tube is shrunk onto the at least two conductors by heating the shrink tube and / or the narrow side walls are deformed at a bending edge or a bending circle and / or the narrow side walls are deformed, in that a compressive force, preferably with a spring or a clamping frame, is applied to the wide side walls.

In an additional embodiment, after the at least one heating composite is introduced into the at least one cavity, a force is applied to the wide side wall and the wide side walls are thereby moved or deformed in the direction of the at least one heating composite, thereby frictionally locking the at least one heating composite, in particular by means of Pinching, between the two broad side walls of the at least one flat tube is attached.

The at least one molded seal consists of an electrically insulating and thermally conductive material. Due to the geometric arrangement of the at least one molded seal within the heat exchanger, the at least two conductors and the at least one electrical resistance heating element are electrically insulated. The molded gasket is in a solid state of aggregation, i. H. not liquid or gaseous, even at high temperatures, eg. 70 ° C or 100 ° C.

In a further embodiment, the at least one molded seal is a film or insulating film, for. Example, a polyimide film (Kapton film), (elastic) ceramic-filled film or a (elastic) ceramic-filled silicone film.

In an additional variant, the heat exchanger has an IP protection class of 67, so that a sufficient waterproofness and dust tightness is present.

A closed pipe is a pipe whose walls are completely closed in a cross section.

In a further embodiment, the corrugated fins and the at least one tube are connected to each other by means of gluing and / or soldering and / or non-positively under prestress.

In a further embodiment, the first and / or second sealing plate has a groove, in which one end of the at least one tube is arranged.

In a further variant, the at least one tube in the groove with a seal, z. B. a, preferably elastic, seal, or an adhesive, sealed.

In a further embodiment, when the volume of the at least one cavity is reduced due to contact between the at least one cavity wall and the at least one molded gasket, the at least one molded gasket is elastically deformed and, by the elastic forces of the at least one molded gasket after the elastic deformation, the at least one molded gasket positively connected with at least one wall of the at least one tube, in particular the at least one molded seal is clamped between two walls.

In a further embodiment, the at least one heat-conducting element and / or the at least one molded seal has a thermal conductivity of at least 1 W / mK, in particular at least 15 W / mK.

In a further embodiment, the at least one molded seal has an electrical insulation of at least 1 kV / mm, in particular at least 25 kV / mm.

In a variant, the at least one molded seal, preferably in cross section, has a dielectric strength of at least 1 kV.

In a further embodiment, the at least one molded seal has a thermal conductivity of at least 1 W / mK, in particular at least 15 W / mK. On the one hand, the at least one molded seal can thus insulate well electrically and, on the other hand, can sufficiently conduct the heat from the electrical resistance heating element to the heat-conducting element or the heat-conducting elements.

Fig. 1

einen Querschnitt einer Kraftfahrzeugklimaanlage,

Fig. 2

eine perspektivische Ansicht eines Wärmeübertragers ohne Deckplatten,

Fig. 3

eine Seitenansicht des Wärmeübertragers gemäß Fig. 2,

Fig. 4

eine Draufsicht des Wärmeübertragers gemäß Fig. 2,

Fig. 5

eine perspektivische Ansicht des Wärmeübertragers gemäß Fig. 2 mit Deckplatten ohne Heizverbund,

Fig. 6

eine Explosionsdarstellung des Wärmeübertragers gemäß Fig. 5,

Fig. 7

einen Querschnitt eines Heizregisters in einem ersten Ausführungsbeispiel gemäß Fig. 2,

Fig. 8

einen weiteren Querschnitt des Heizregisters gemäß Fig. 7,

Fig. 9

eine Explosionsdarstellung des Heizregisters,

Fig, 10

eine perspektivische Ansicht des Wärmeübertragers ohne Deckplatten in einem ersten Ausführungsbeispiel,

Fig. 11

eine perspektivische Ansicht des Wärmeübertragers ohne Deckplatten in einem zweiten Ausführungsbeispiel,

Fig. 12

einen Querschnitt eines Rohres mit einer Einlage,

Fig. 13

einen Querschnitt des Rohres gemäß Fig. 12 mit dem Heizverbund,

Fig. 14

einen Querschnitt des Rohres gemäß Fig. 12 nach einem Zusammendrücken von Breitseitenwandungen,

Fig. 15

einen Querschnitt des Rohres ohne der Einlage in einem weiteren Ausführungsbeispiel und

Fig. 16

einen Längsschnitt des Heizregisters.

Hereinafter, embodiments of the invention will be described in more detail with reference to the accompanying drawings. It shows:

Fig. 1

a cross section of an automotive air conditioning system,

Fig. 2

a perspective view of a heat exchanger without cover plates,

Fig. 3

a side view of the heat exchanger according to Fig. 2 .

Fig. 4

a plan view of the heat exchanger according to Fig. 2 .

Fig. 5

a perspective view of the heat exchanger according to Fig. 2 with cover plates without heating compound,

Fig. 6

an exploded view of the heat exchanger according to Fig. 5 .

Fig. 7

a cross section of a heating register in a first embodiment according to Fig. 2 .

Fig. 8

a further cross section of the heater according to Fig. 7 .

Fig. 9

an exploded view of the heating register,

Fig. 10

a perspective view of the heat exchanger without cover plates in a first embodiment,

Fig. 11

a perspective view of the heat exchanger without cover plates in a second embodiment,

Fig. 12

a cross section of a pipe with an insert,

Fig. 13

a cross-section of the pipe according to Fig. 12 with the Heizverbund,

Fig. 14

a cross-section of the pipe according to Fig. 12 after compression of broad side walls,

Fig. 15

a cross section of the tube without the insert in a further embodiment and

Fig. 16

a longitudinal section of the heater.

Fig. 1 shows an automotive air conditioning 24. In an air conditioning case 26 having a bottom wall 27 and an outlet portion 29, a fan 25, an air filter 30, a refrigerant evaporator 31 and a heat exchanger 1 is arranged as an electric heater. The air conditioning housing 26 thus forms a channel 35 for passing the air. Housing walls 28 of the air conditioning housing 26 have on the inside a surface 36 which define the channel 35. The air for the interior of a motor vehicle is passed by means of the blower 25 through the air filter 30, the refrigerant evaporator 31 and the heat exchanger 1.

The automotive air conditioning system 24 is thus not provided with a heat exchanger through which coolant flows for heating the air conducted through the motor vehicle installation 24. The air conducted by the motor vehicle air conditioning system 24 is electrically heated exclusively by means of the heat exchanger 1. The motor vehicle air conditioning system 24 is preferably used in a motor vehicle with exclusively electric drive or with a hybrid drive (not shown). In order to achieve the necessary electrical heating power by means of the heat exchanger 1, the heat exchanger with high voltage, eg. B. with more than 50 volts, for example, 60 V or 600 V, operated to not too large Amperages and thus too thick power lines (not shown) to get.

In the Fig. 2 to 16 An exemplary embodiments of the heat exchanger 1 for the motor vehicle air conditioning system 24 are shown. An aluminum tube 18 designed as a flat tube 13 has two broad side walls 20 and two narrow side walls 21 (FIG. Fig. 8 . 12, 13, 14 and 15 ) on. The width and narrow side walls 20, 21 thereby represent cavity walls 17, which enclose a cavity 19 within the tube 18. The width and Schmalseitenwandungen 20, 21 of the tube 18 are thus walls 16 of the tube 18. In this case, the walls 18 in cross-section no joint, z. As a tongue and groove connection, a welding or soldering, on. The tube 18 is made in one piece as a closed wall 18 with extrusions, so that no joints are required in cross section on the tube 18.

Within the flat tube 13, two molded seals 23 are arranged as electrical insulating elements 22. The two form seals 23 are made of elastic silicone. On the two rectangular shaped seals 23 ( Fig. 7, 8 . 13 and 14 ) are two conductors 4, namely a first circuit board 6 and a second circuit board 7, on. Between the two circuit boards 6, 7 three PTC elements 3 designed as electrical resistance heating elements 2 are arranged. The PTC elements 3 are connected to each other with the two printed circuit boards 6, 7 with adhesive. At the two conductors 4, an electrical contact plate 5 is formed in each case ( Fig. 3 and 9 ). The cavity 19 enclosed by the cavity walls 17 of the flat tube 13 is a void 32 in the region of the narrow side walls 21, ie in the void 32 only air ( Fig. 8 ).

As a result, the two circuit boards 6, 7 with the interposed three PTC elements 3 due to the electrical insulation of the molded gaskets 23 electrically isolated. The electrical contacting of the two circuit boards 6, 7 takes place by means of not shown electrical lines to the contact plates 5. The two circuit boards 6, 7 with the three PTC elements 3 thereby constitute a heating unit 10. After arranging the two form seals 23 on the heating unit After forming the heating system 8 into the flat tubes 13 with the corrugated fins 12, a heating coil 9 or the heat exchanger 1 is present. Several heater 9 as shown in FIG Fig. 2 . 10 and 11 can also be connected to a heat exchanger 1 with a larger number of heating registers 9 to each other.

The net height H _{N of} the heat exchanger 1 as shown in FIG Fig. 3 is about 50 to 300 mm, preferably 100 to 200 mm and the mesh width B _N is about 50 to 300 mm, preferably 100 to 200 mm. The transverse division Q, ie the distance between the flat tubes 13 as shown in FIG Fig. 4 , is in this case between 5 and 30 mm, preferably 9 to 18 mm and the overall depth T _N as shown in FIG Fig. 8 is 6 to 50 mm, preferably 10 to 40 mm. The overall depth T _R is 10 to 50 mm, preferably 10 to 40 mm. The thickness D _{E of} the printed circuit boards 6, 7 is 0.2 to 1.5 mm, the thickness D _{I of} the molded seals 23 0.1 to 1.5 mm and the width B _{R of} the tube 18 is 2 to 10 mm. The thickness D _{stone of} the PTC elements 3 is in the range between 0.8 to 3 mm.

Between the flat tubes 13 corrugated fins 12 are arranged as Wärmeleitelemente 11 ( Fig. 2 . 3 . 5 . 10 and 11 ). The corrugated fins 12 serve to enlarge the surface of the heat exchanger 1, in order to better release the heat emitted by the PTC elements 3 to the air, which flows through the heat exchanger 1. The heating coil 8, consisting of the two printed circuit boards 6, 7, the PTC elements 3 and the molded seal 23 is thereby only after the manufacture of the flat tube 13 in the Flat tube 13 inserted. The relevant manufacturing steps are in the Fig. 12 to 14 shown. The corrugated fins 12 can be connected to the corrugated fins 12 either before or after the heating composite 8 is introduced into the flat tube 13. The corrugated fins 12 can be connected to the flat tubes 13, for example, by gluing, welding or soldering. In addition, it is also possible to connect the corrugated fins 12 frictionally with the flat tubes 13, because a pressure force 33 is applied to a heat exchanger 1 with a plurality of flat tubes 13 or heating coils 9 and due to this pressure force 33 (FIG. 10 and 11 ), the corrugated fins 12 can be held frictionally between the flat tubes 13.

In Fig. 12 is a flat tube 13 with attached corrugated fins 12 shown in a cross section. Within the enclosed by the flat tube 13 cavity 12, a liner 38 or an inlay 38 is present. During the joining of the corrugated fins 12 with the flat tubes 13, low pressure forces in the region of the broad side walls 20 of the flat tube 13 may occur. In order to prevent resulting deformations and a reduction of the cavity 19, the insert 38 is arranged in the cavity 19. The insert 38 is not required if the flat tube 13 has a sufficiently high rigidity in order to be able to counteract these forces during the assembly of the corrugated fins 12 with the flat tube 13, without any deformation occurring on the flat tube 13. After joining, z. B. by means of soldering, the corrugated fins 12 to the flat tube 13, the insert 38 is removed from the flat tube 13 and then the heating composite 8 with the PTC elements 3 the two circuit boards 6, 7 and two molded seals 23 inserted into the flat tube 13 ( Fig. 13 ). The two form seals 23 have a substantially rectangular cross-sectional shape. It is thus a matter of two separate molded seals 23. Deviating from this, the molded seal 23 can also be used as a hose 34 (FIG. Fig. 9 ) be formed. The hose 34 can In this case, be attached to the heating unit 10 with the two circuit boards 6, 7 and the PTC elements 3 as a shrink tube by shrinking under heating. During the insertion of the heating system 8 in the flat tube 13 ( Fig. 13 ), the distance between the two wide side walls 20 of the flat tube 13 is greater than the thickness of the heating composite 8, ie the distance between the two form seals 23. There is thus a distance between the two form seals 23 and the two wide side walls 20 before. As a result, the heating composite 8, the flat tube 13 can be easily inserted. After inserting the heating composite 8 into the flat tube 13, a compressive force 33 is applied to the two wide side walls 20 or to the corrugated fins 12 ( Fig. 14 ), so that the narrow side walls 21 deform or bend substantially at a bending edge 39 and thereby the distance between the two broad side walls 20 is reduced, so that the two wide side walls 20 are pressed onto the two form seals 23 of the heating system 8. In this in Fig. 14 illustrated state of the heating register 9 are thus the two narrow side walls 21 braced and the heating system 8 positively, in particular by means of clamping, clamped between the two broad side walls 20. The pressure force 33 is, for example, by means of a not in Fig. 10 shown tension spring applied to the heat exchanger 1 with a plurality of heating registers 9 or by means of an in Fig. 11 shown tenter 37.

The flat tube 13 can next to the in the Fig. 12 to 14 illustrated embodiment with the narrow side wall 21 with a bending edge 9 as a flat tube 13 with narrow side walls 21 in the geometric shape of a bending circle as shown in FIG Fig. 14 be educated. The manufacturing steps for connecting the heating composite 8 with the flat tube 13 according to Fig. 15 correspond in an analogous manner to the embodiment of the flat tube 13 according to the first embodiment, which in the Fig. 12 to 14 is shown.

After inserting the Heizverbünde 8 in the flat tubes 13 and the application of the compressive force 33 to the heat exchanger 1, an upper first cover plate 14 is applied to the upper ends of the flat tubes 13 and applied to the lower second ends of the flat tubes 13, a second lower cover plate 15 ( Fig. 5, 6 and 16 ). The first and second cover plate 14, 15 in this case has a plurality of substantially rectangular grooves into which the ends of the flat tubes 13 are inserted. In the grooves at the lower end of the grooves in each case a cutout 40 ( Fig. 16 ) available. In the cutout 40, for example, an adhesive is introduced as a seal 41. After insertion of the flat tubes 13 in the grooves of the first and second cover plate 14, 15, the ends of the flat tubes 13 are glued to this adhesive and thereby a liquid and dust-tight connection and sealing between the flat tubes 13 and the first and second cover plate 14, 15 produced. As a seal 41, for example, silicone can be used in addition to adhesive. The first and second cover plate 14, 15 consists of metal or plastic. As a result, all the flat tubes 13 of the heat exchanger 1 are dust-tight and sealed against the environment of the heat exchanger 1. Thus, to the circuit boards 6, 7 or the PTC elements 3 within the cavity 19 no liquid and no dust penetrate.

An upper side of the first upper cover plate 14 is connected dust-tight and liquid-tight with the air conditioning housing 26, so that no dust and no liquid can penetrate into the cavity 19 at the upper ends of the flat tubes 13. Notwithstanding this may be on the top of the first upper cover plate 14 also dust and liquid-tight an electronic housing attached (not shown).

The arranged within the channel 35 of the motor vehicle air conditioner 24 heat exchanger 1 is thus sealed dust and liquid-tight. dust or liquid within the channel 35 can thus not penetrate into the cavity 19 within the flat tubes 13.

Overall, significant advantages are associated with the heat exchanger 1 according to the invention and the motor vehicle air conditioning system 24 according to the invention. The heating assembly 8 is arranged dust and liquid-tight within the flat tubes 13, so that in the air duct 35 existing dust particles or liquid can cause no damage to the heat exchanger 1. The molded seal 23 is a commercially available insulating film and can thus be made available inexpensively in the production.

LIST OF REFERENCE NUMBERS

1

Heat exchanger

2

Electric resistance heating element

3

PTC element

4

ladder

5

Electric contact plate

6

First circuit board

7

Second circuit board

8th

Heizverbund

9

heater

10

heating unit

11

thermally conductive element

12

corrugated fins

13

flat tube

14

First cover plate

15

Second cover plate

16

Walls of the pipe

17

cavity wall

18

pipe

19

cavity

20

Breitseitenwandung

21

narrow side

22

Electrical insulating element

23

shaped seal

24

Automotive air conditioning system

25

fan

26

Air conditioning case

27

bottom wall

28

housing

29

exit section

30

filter

31

Refrigerant evaporator

32

White space within the flat tube

33

thrust

34

tube

35

channel

36

surface

37

tenter

38

inlay

39

bending edge

40

cutout

41

seal

H _N

net height

B _N

net width

Q

transverse pitch

T _N

overall depth

T _R

overall depth

D _E

Thickness of the printed circuit board

D _I

Thickness of the molded gasket

B _R

Width of the flat tube

D _stone

Thickness of the PTC stone

Claims (15)

Heat exchanger (1) comprising at least one electrical resistance heating element (2), in particular at least one PTC element (3), - At least two with the at least one electrical resistance heating element (2) electrically conductively connected conductor (4), in particular printed circuit boards (6, 7) to conduct electrical current through the at least one electrical resistance heating element (2) and thereby the electrical resistance heating element (2) to warm, at least one heat-conducting element (11) for transmitting heat from the at least one electrical resistance heating element (2) to a fluid to be heated, - At least one electrical insulating element (22), which electrically isolates the at least two conductors (4), preferably of the at least one heat conducting element (11), wherein - The at least two conductors (4) and / or the at least one electrical resistance heating element (2) in at least one of at least one cavity wall (17) limited cavity (19) are arranged and the at least one electrical insulating element (22) at least one molded seal (23 ), characterized in that the at least one cavity wall (17) is designed as at least one closed tube (18) without a joint in cross-section. Heat exchanger according to claim 1, characterized in that the at least one tube (18) as at least one flat tube (13) is formed with two broad side walls (20) and two narrow side walls (21) and the two narrow side walls (21) by means of one on the two broad side walls (20) acting compressive force are braced, in particular the two narrow side walls (21) are braced at a bending edge (39) or a bending circle. Heat exchanger according to Claim 1 or 2, characterized in that the at least one heat-conducting element (11) comprises at least one tube (18) and / or the at least one heat-conducting element (11) comprises corrugated ribs (12) which are externally attached to the at least one tube (11). 18), in particular by means of soldering or gluing, are arranged and / or the at least two conductors (4) have no direct contact with the at least one tube (18). Heat exchanger according to one or more of the preceding claims, characterized in that the at least one heat-conducting element (11), in particular the at least one tube (18) and / or the corrugated fins (12), at least partially, in particular completely, of metal, for example aluminum or Steel, or plastic. Heat exchanger according to one or more of the preceding claims, characterized in that the at least one molded seal (23) between each wall (16, 17) of the at least one tube (18) and a conductor (4) is arranged, so that the at least two conductors (4) are electrically insulated with respect to the at least one tube (18) Heat exchanger according to one or more of the preceding claims, characterized in that two, preferably substantially rectangular, shaped seals (23) are arranged in the cavity (19)
or
the at least one molded seal (23) in the cavity (19) as a hose (34), in particular shrink tube (34) is formed. Heat exchanger according to one or more of the preceding claims, characterized in that the at least one molded seal (23) is elastic and / or the at least one molded seal (23) consists at least partially of silicone or plastic or rubber and / or the at least one molded seal (23 ) is connected to the at least one tube (18) non-positively and / or positively and / or cohesively and / or the at least one molded seal (23) is a film. Heat exchanger according to one or more of the preceding claims, characterized in that the at least one molded seal (23) heat-transmitting or thermally conductive particles, for. For example, alumina and / or silicon carbide and / or boron nitride, and / or the at least one tube (18) from a first, z. B. top, cover plate (14) at a first end, in particular fluid-tight, is closed and / or at least one tube (18) from a second, z. B. lower, cover plate (15) at a second end, in particular fluid-tight, is closed. Heat exchanger according to one or more of the preceding claims, characterized in that the at least one electrical resistance heating element (2), the at least two conductors (4) and the at least one molded seal (23) are connected to at least one heating compound (8), which or which is arranged within the at least one tube (18) and are preferably and a plurality of tubes (18) each with a heating compound (8) and between the tubes (18) arranged corrugated fins (12) form the heat exchanger (1), in particular by means of a Clamping frame (37) or a spring on the walls (16, 17) of the at least one tube (18), in particular the broad side walls (20) of the at least one flat tube (13), the compressive force is applied. Motor vehicle air conditioning system (24), characterized in that the motor vehicle air conditioning system (24) comprises at least one heat exchanger (1) according to one or more of the preceding claims. Method for producing a heat exchanger (1) or an automotive air conditioning system (24), in particular a heat exchanger (1) according to one or more of claims 1 to 9 or an automotive air conditioning system (24) according to claim 10, comprising the steps: provide at least one electrical resistance heating element (2), in particular at least one PTC element (3), - Providing at least two electrical conductors (4), in particular circuit boards (6, 7), for passing electrical current through the at least one electrical resistance heating element (2), providing at least one heat conducting element (11) for transmitting heat from the at least one electrical resistance heating element (2) to a fluid to be heated, providing at least one electrical insulating element (22) as a molded seal (23) for electrically insulating the at least one heat conducting element (11) from the at least two conductors (4), Connecting the at least two conductors (4) to the at least one electrical resistance heating element (2), thermally connecting the at least one heat-conducting element (11) to the at least one conductor (4) and / or to the at least one electrical resistance heating element (2), electrically insulating the at least two conductors (4), preferably from the at least one heat conducting element (11), by means of the at least one molded seal (23), by connecting the at least two conductors (4) to the at least one electrical resistance heating element (2) and the at least a form seal (23) are connected to at least one heating compound (8), - wherein the at least one heat-conducting element (11) comprises at least one cavity wall (17) which encloses at least one cavity (19) and the at least one cavity wall (17) is formed by at least one tube (18), characterized in that
the tube (18), in particular by means of extrusion, is produced with a closed cross-section without a joint. A method according to claim 11, characterized in that the at least one tube (18) as at least one flat tube (13) is produced and the at least one heating compound (8) in the at least one cavity (19) of the at least one closed in cross-section Flat tube (13) is enclosed, is introduced and then the flat tube (13) on the narrow side walls (21) is deformed and thus braced, so that the Breitseitenwandungen (20) of the flat tube (13) on the at least one molded seal (23) is pressed. A method according to claim 12, characterized in that during the introduction of the at least one heating composite (8) in the at least one cavity (19), the thickness of the at least one cavity (19) between the two broad side walls (20) is greater than the thickness of the Heizverbundes (8) between the at least one molded seal (23). A method according to claim 12 or 13, characterized in that after the introduction of the at least one heating composite (8) in the at least one cavity (19), the shape of the at least one cavity wall (17) is changed, in particular is bent, so that the volume of at least one cavity (19) is reduced, and preferably thereby the heating composite (8) is non-positively connected to the broad side walls (20) of the at least one flat tube (13). Method according to one or more of claims 11 to 14, characterized in that the at least one molded seal (23) as a shrink tube (34) is formed and the shrink tube (34) is shrunk onto the at least two conductors (4) by the shrink tube (34) is heated and / or the narrow side walls (21) are deformed at a bending edge (39) or a bending circle and / or the narrow side walls (21) are deformed by applying to the broad side walls (20) a compressive force, preferably with a spring or a clamping frame (37). , is applied.

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