EP4279835A1 - Electric heating device, method for producing an electric heating device and use of a heat exchanger - Google Patents

Abstract

What is proposed is an electric heater (1) for heating a media stream, comprising at least one electronic component (17) for controlling the power of the heater (1), wherein the at least one electronic component (17) is arranged on a holding part (2) which is in a Channel (11, 12) of a heat exchanger (3) of the heater (1) projects into it or forms at least one wall (18, 19) of the channel (11, 12), and the holding part (2) has a heat-conducting contact on both sides with the at least one electronic Component (17). For example, the holding part (2) can each form a wall (18, 19) of two channels (11, 12) of the heat exchanger (3) and the at least one electronic component (17) between the walls (18, 19) of the holding part ( 2) be arranged. Advantageously, an arrangement of the at least one electronic component (17) can be achieved in which excellent cooling can be achieved and, in addition, mechanical forces that occur when the heater (1) is installed do not affect the electronic components (17) or their fastening can affect.

Description

The invention relates to an electric heater, a method for producing an electric heater and a use of a heat exchanger.

Electrical heating devices for heating a media flow, for example water for hot water supply, such as instantaneous water heaters, usually have a heating device comprising heating coils or heating rods that convert electrical current into thermal energy and release it to the water to be heated. Especially with instantaneous water heaters, a high output of often more than 15 kW [kilowatt] can be achieved. To control and/or regulate the electric heater, power electronics are used, comprising electronic components, for example semiconductor components such as TRIACs. Due to the high electrical power to be implemented, the electronic components can heat up significantly during operation.

In order to ensure cooling of the electronic components DE 41 06 273 C1 proposed to attach the electronic components arranged on a circuit board to a metal block and with this to a water-conducting pipe section in a heat-conducting manner.

The DE 102 09 905 A1 shows a solution in which TRIACs are not arranged on a circuit board, but on closure pieces that are in contact with the medium to be heated.

In the DE 10 2011 0130972 A1 In order to improve the cooling of electronic components of a heater, it is taught to provide a heat sink that is connected to a water guide body and a semiconductor switch as an electronic component. The heat sink can cause a pressure force from the heat sink to the semiconductor switch due to the pressure of the water in the device. The disadvantage is that the semiconductor switch is not fixed by the heat sink, so that the semiconductor switch can accidentally change its position during assembly work.

The DE 10 2018 008 511 A1 relates to an electric heating device with a housing and a stack of heating elements, with a heat-generating element that has a hollow profile or flat profile. The heating elements are cohesively connected to the housing. The electronic components are arranged below a jacket of a water-conducting area and can disadvantageously shift during assembly or installation work on the heating device.

The EP 2 098 802 A2 shows a control device for a hot water device, in which a cooling pipe is provided which has two opposite cooling surfaces on which electronic components to be cooled are to be arranged.

From the DE 10 2010 051 736 A1 shows an instantaneous water heater with a plurality of power electronic switching elements that are placed flat or lying on a circuit board. Furthermore, a cooling pipe is provided through which cold water flows during operation, whereby the switching elements are cooled. The cooling tube is placed on the flat or lying switching elements and fixed using a clamp.

What the solutions mentioned have in common is a high level of effort for assembling the electronic components to ensure cooling. In addition, some of them have to be complex Additional components to be manufactured, such as heat sinks or metal blocks, are used. Last but not least, the electronic components have to be laboriously fixed in a position for cooling. Another problem is the arrangement on a line carrying the medium to be heated, the line usually being intended for a connection to a house connection. During installation, damage to the electronic components often occurs as a result of the connection and the resulting mechanical forces.

Based on this, it is the object of the invention to propose an electric heater that at least partially overcomes the problems described in the prior art. In particular, very good cooling of electronic components of the heater should be guaranteed and the electronic components should also be protected from external mechanical influences.

In addition, the invention should at least not significantly increase the complexity of a heater and combine the advantages of simple assembly without essential additional components with very good cooling performance.

These tasks are solved by the features of the independent patent claims. Further advantageous embodiments of the solution proposed here are specified in the independent patent claims. It should be noted that the features listed in the dependent patent claims can be combined with one another in any technologically sensible manner and define further embodiments of the invention. In addition, the features specified in the patent claims are specified and explained in more detail in the description, with further preferred embodiments of the invention being presented.

For this purpose, an electric heater contributes to heating a media flow, having at least one electronic component for controlling the power of the heater, the at least one electronic component being arranged on a holding part which projects into a channel of a heat exchanger of the heater or forms at least one wall of the channel and the holding part has heat-conducting contact on both sides with the at least one electronic component.

The heater is, for example, an electric instantaneous water heater that is set up to heat a media stream (water stream). For this purpose, the heater can have a heat exchanger, also known as a heating block, with resistance-based heating elements that are brought into contact with the media flow and can supply thermal energy to it. The heat exchanger can be connected to a cold water supply line in the heater. The heat exchanger can include channels through which the medium to be heated flows and in which resistance-based heating elements can be arranged. The channels can be arranged or shaped in a meandering manner in the heat exchanger. The heater can in particular have an electrical heating output in a range between 10 kW and 30 kW [kilowatt].

The resistance-based heating element can in particular be a heating coil or a heating rod or a plurality of the same, designed to convert electrical current into thermal energy and to deliver it to the media stream. The heating element can usually be brought into direct contact with the media stream to be heated, which means that short response times for the heating device can be achieved. Heating wires are known from the prior art for this purpose.

The electric heater can be set up to be connected to a three-phase alternating current source for energy supply. The three-phase alternating current source can be, for example, a three-phase connection in a household, often also referred to as a three-phase connection.

To regulate or control the heater, it can include electronic components. Semiconductor switches such as TRIACs, which can switch high heating currents, are often used. TRIACs, also known as bidirectional thyristor triode or symistor, are semiconductor components that are able to switch high alternating currents. When operating electronic components, especially switches such as TRIACs or other semiconductors, a lot of waste heat can be generated during operation. A heater proposed here has at least one such electronic component; as a rule, one electronic component is provided for each heating element. Heaters often have 3 to 10 such electronic components. These can in particular be arranged on a circuit board.

One aspect therefore relates to the arrangement of the at least one electronic component with a heat-conducting contact towards a heat exchanger of the heater. For this purpose, in particular there can be heat-conducting contact with a medium (water to be heated) flowing through the heat exchanger. Advantageously, forces acting on a connection of the heater cannot damage the at least one electronic component or change its position during installation.

According to one embodiment, the at least one electronic component can be arranged on a holding part, the holding part being in heat-conducting contact with at least one channel of the heat exchanger. The area in which the holding part is brought into heat-conducting contact with the at least one channel, viewed in the flow direction of the medium flowing through, can be arranged in an initial area (area of an inlet) of the heat exchanger, in particular in front of the at least one heating element. An improved cooling effect can advantageously be achieved in this way. The phrase “arranged on a holding part” refers to a (direct) connection of the at least one electronic component to the holding part, in particular a reception of the at least one electronic component between two walls of the holding part and/or a clamping of the at least one electronic component by the holding part.

The holding part can in particular consist of or include a very good heat-conducting material. The material can be, for example, a metal, for example steel, copper or aluminum, or alloys containing at least one of these metals, for example brass. A holding part made of sheet metal, which also has good heat-conducting properties, can be produced particularly cost-effectively.

According to one embodiment, the holding part can have heat transfer ribs on the channel side. These can increase the surface area available for heat transfer and thus improve heat transfer performance.

According to one embodiment, the holding part can have a connection to an electrical ground of the heater and thus realize grounding of the electronic components or the circuit board. Advantageously, this is particularly easy to implement structurally.

According to one embodiment, the holding part can each form a wall of two channels of the heat exchanger and the electronic components are arranged between the areas of the holding part that form the walls. In other words, the holding part can form a first wall of a first channel and a second wall of a second channel. The walls can in particular be aligned (largely) parallel and have a distance that corresponds to a width of the at least one electronic component to be accommodated. Advantageously, cooling of the at least one electronic component can be achieved on both sides. It can also be advantageous the walls can be used to clamp the at least one electronic component, making complex means for fastening the at least one electronic component unnecessary.

According to one embodiment, the holding part can protrude into a channel. The holding part can largely penetrate a flow cross section of the channel in order to provide a large area for heat transfer. The holding part can in particular be aligned in an expansion direction in the flow direction of the channel in order not to hinder a flow in the channel and to offer a large area for heat transfer.

In particular, an area of the holding part that does not protrude into the channel can form a clamping area for the at least one electronic component. For this purpose, the holding part can have a deflection, so that two opposite areas of the holding part are formed, between which the at least one electronic component can be accommodated on both sides in a cooling manner.

According to one embodiment, at least one seal can be arranged between the holding part and the heat exchanger, which prevents medium to be heated from escaping in the contact area between the channel and the holding part.

According to one embodiment, thermal paste can be introduced between the electronic component and the holding part, which further improves heat transfer and heat conduction.

According to one embodiment, the at least one electronic component can be arranged on a circuit board, with the circuit board being fixed in its position. The circuit board can be attached to a suitable fastening point, for example a housing or a holding plate of the heater, using fastening means, for example a screw connection. be fixed. The circuit board can be particularly advantageously inserted in a clamp connection. Clamping elements for this can, for example, be formed on the heat exchanger. A clamp connection advantageously and cost-effectively enables simple and quick assembly or disassembly of the circuit board. Advantageously, by fixing the circuit board, there is no need to fasten the at least one electronic component on or in the holding part, since there is already a very good mechanical hold, particularly with an arrangement of the electronic component and holding part that makes contact on both sides.

According to a further aspect, a method for producing a heater proposed here is also proposed, wherein a heat exchanger is produced by injection molding and a holding part for at least one electronic component for power control of the heater is integrated into the heat exchanger during injection molding. In other words, the holding part is integrated and fixed in the heat exchanger in a form-fitting and/or material-locking manner in the injection molding process and is thereby media-tight.

According to a further aspect, the use of a heat exchanger of an electric heater for cooling at least one electronic component of the heater is also proposed.

As a precaution, it should be noted that the number words used here ("first", "second", ...) primarily serve (only) to distinguish between several similar objects, sizes or processes, i.e. in particular no dependency and/or order of these objects, sizes or prescribe processes to each other. If a dependency and/or sequence is required, this is explicitly stated here or it will be obvious to the person skilled in the art when studying the specifically described embodiment. To the extent that a component can occur multiple times ("at least one"), the description of one of these components can apply equally to all or part of the majority of these components, but this is not mandatory.

The details, features and advantageous configurations discussed in connection with the heater can also occur in the method of production and use presented here and vice versa. In this respect, full reference is made to the statements there regarding the more detailed characterization of the features.

An electric heater is therefore specified here which can at least partially solve the problems described with reference to the prior art. In particular, the heater at least contributes to ensuring excellent cooling of electronic components, with the risk of damage to the at least one electronic component or its attachment during installation of the heater being largely eliminated.

In addition, the invention allows simple assembly of the heater while at the same time providing very good cooling of the at least one electronic component due to heat-conducting contact on both sides in the holding part.

Fig. 1:

ein hier vorgeschlagenes elektrisches Heizgerät,

Fig. 2:

zwei Kanäle eines Wärmetauschers mit Halteteil und elektronischen Bauteilen, und

Fig. 3:

einen Kanal eines Wärmtauschers mit in den Kanal ragendem Halteteil.

The invention and the technical environment are explained in more detail below using the accompanying figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments given. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figures and combine them with other components and findings from the present description. In particular, it should be noted that the figures and in particular the proportions shown are only schematic. Show it:

Fig. 1:

an electric heater proposed here,

Fig. 2:

two channels of a heat exchanger with a holding part and electronic components, and

Fig. 3:

a channel of a heat exchanger with a holding part protruding into the channel.

Fig. 1 shows an example and schematic of an electric heater (1) for heating a media stream, such as a water stream, which can be supplied to the heater 1 through a cold water inlet 8 and removed through a hot water outlet 9, the media stream flowing through the heater 1 in a flow direction 21.

The heater 1 can include a heat exchanger 3, having resistance-based heating elements that can be brought into direct contact with the media flow. In an entrance area, i.e. in an initial area of the heat exchanger 3 seen in the flow direction 21, a holding part 2 with at least one electronic component 17 can be arranged, the at least one electronic component 17 being brought into heat-conducting contact with the heat exchanger 2 and a medium flowing through.

The heater 1 can also have a regulating and control device 6, which can be set up to regulate and control the heater 1, in particular the heating elements. For this purpose, the control and control device 6 can be electrically connected to a temperature sensor 7 in the cold water inlet, a flow sensor 5, a motor valve 4 and a temperature sensor 10 in the hot water outlet 9.

Fig. 2 also shows, by way of example and schematically, two channels 11, 12 of the heat exchanger 3, between which a holding part 2 with at least one electronic component 17 can be arranged. The first and second channels 11, 12 can be adjacent channels of a meandering line in the heat exchanger 3. The holding part 2 can be shaped in such a way that it forms a first wall 18 of the first channel 11 and a second wall 19 of the second channel 12, the first and second walls 18, 19 being arranged largely parallel and being able to have a distance that is largely equal to the insertion width 20 of the at least one electronic component 17 corresponds, whereby good heat-conducting contacting of the at least one electronic component 17 between the first and second walls 18, 19 is ensured.

The at least one electronic component 17 can be arranged on a circuit board 14. The circuit board 14 can be fixed in fasteners 15. The fastening means 15 are advantageously designed here as a clamping device, which can be formed as part of the manufacturing process of the heat exchanger 3, for example as part of an injection molding process.

Fig. 3 shows, by way of example and schematically, a channel 11 of the heat exchanger with a holding part 2 projecting into the channel 11. The holding part 2 can include a clamping area 16, in which the holding part 2 can be designed in the shape of a clamp and can be set up to hold the at least one electronic component 17. In addition, the holding part 2 can include a cooling area 13 which projects into the channel 11 and implements heat exchange with a medium flowing through the channel 11. The cooling area 13 can project into the channel 11 over as large an area as possible and be aligned in the flow direction 21 in order not to impede the flow in the channel and at the same time to enable a large heat flow from the holding part 2 to the medium flowing through the channel 11.

Reference symbol list

1

heater

2

holding part

3

Heat exchanger

4

Engine valve

5

Flow sensor

6

Control and control device

7

Temperature sensor

8th

Cold water inlet

9

Hot water outlet

10

Temperature sensor

11

first channel

12

second channel

13

Cooling area

14

circuit board

15

Fasteners

16

Clamping area

17

electronic component

18

first wall

19

second wall

20

Insertion width

21

Direction of flow

Claims (10)

Electric heater (1) for heating a media stream, comprising at least one electronic component (17) for controlling the power of the heater (1), the at least one electronic component (17) being arranged on a holding part (2) which is inserted into a channel (11 , 12) of a heat exchanger (3) of the heater (1) projects into it or forms at least one wall (18, 19) of the channel (11, 12), and the holding part (2) has heat-conducting contact on both sides with the at least one electronic component (17 ) has. Electrical heater (1) according to claim 1, wherein the at least one electronic component (17) for controlling the power of the heater (1) is a semiconductor component and/or a TRIAC and is arranged on a circuit board (14). Electric heater (1) according to one of the preceding claims, wherein the holding part (2) has heat transfer ribs on the channel side. Electric heater (1) according to one of the preceding claims, wherein the holding part (2) comprises an electrical connection to an electrical ground of the electric heater (1). Electric heater (1) according to one of the preceding claims, wherein the holding part (2) forms a wall (18, 19) of two channels (11, 12) of the heat exchanger (3) and the at least one electronic component (17) between the Walls (18, 19) of the holding part (2) is arranged. Electric heater (1) according to one of the preceding claims, wherein the holding part (2) comprises a clamping area (16) for the at least one electronic component (17). Electric heater (1) according to one of the preceding claims, wherein a seal is arranged between the holding part (2) and the channel (11, 12). Electric heater (1) according to one of the preceding claims, wherein thermal paste is inserted between the electronic component (17) and the holding part (2). Method for producing an electric heater (1), wherein a heat exchanger (3) is produced by injection molding and a holding part (2) for at least one electronic component (17) for controlling the power of the heater (1) is integrated into the heat exchanger (3) during injection molding becomes. Use of a heat exchanger (3) of an electric heater (1) for cooling at least one electronic component (17) of the heater (1).

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