EP3779280A1 - Heating device for a building - Google Patents

Abstract

The invention relates to a heating device (1) for a building, in which a mixture of fuel gas and air (2) is fed into a combustion chamber (3) and ignited there, characterized in that the heating device (1) is used to burn a fuel mainly containing hydrogen Combustion gas is set up such that a catalyst material (4) is arranged in the heater (1) to ignite the fuel gas-air mixture, that a temperature sensor for monitoring the combustion is formed in the region of the catalyst material (4) and that the temperature sensor is connected to the catalyst material (4) is formed.

Description

The invention relates to a heating device for a building, a method for monitoring the combustion in the heating device and the use of a catalyst material. In particular, the invention is used for igniting and monitoring hydrogen condensing boilers.

The usual energy source for condensing boilers is natural or liquid gas. Either an electric spark or a glow element is used to ignite the combustion process. Both measures provide the activation energy necessary to start the reaction. In addition to a device for igniting the flame, condensing boilers generally also have a unit for monitoring the flame in order to prevent an unburned gas-air mixture from flowing out. The gas types mentioned above contain hydrocarbons (CH4, C2H6, C3H8, ...) which contain ionized oxidation intermediates, especially CH radicals, during combustion. This effect is used when monitoring a flame, in that when an electric field is applied to the flame area, it is measured whether an ionization current to be expected is actually present.

The function groups "ignition" and "monitoring" can only partially be combined, if at all, in such natural or liquid gas condensing boilers, so that the frequent need for different functional units or increased integration effort results in comparatively high costs in the product. Furthermore, the electrodes placed in the combustion chamber are subject to high requirements in terms of geometric positioning.

In the case of fuel gases that contain hydrogen exclusively or in high proportions, no ionized carbon-based oxidation intermediates occur during combustion, so that the method for flame monitoring described in the prior art cannot be used.

It is therefore the object of the invention to provide a heating device and a method which are suitable for the ignition and monitoring of hydrogen-rich fuel gases and preferably reduce or even overcome the disadvantages of the prior art.

This object is achieved according to the features of claim 1 in that the heater is set up to burn a fuel gas containing predominantly hydrogen, that a catalyst material is arranged in the heater to ignite the fuel gas-air mixture, that in the area of the catalyst material a temperature sensor for Monitoring the combustion is formed and that the temperature sensor is formed with the catalyst material.

Advantageous refinements result from the features of the dependent claims.

Contributing to this is a heating device for a building, in which a fuel gas-air mixture flow is fed into a combustion chamber and ignited there, the heating device being set up to burn a fuel gas containing predominantly hydrogen, with a catalyst material for igniting the fuel gas-air mixture is arranged in the heater, wherein a temperature sensor for monitoring the combustion is formed in the region of the catalyst material and wherein the temperature sensor is formed with the catalyst material.

The heater is generally used to heat a building, such as a residential building, and / or in particular to heat a water supply system, such as a water circuit in the residential building. The heater is usually a gas heater. In other words, this relates in particular to a heater which is set up to burn one or more gases, possibly with the supply of ambient air from a building, in order to generate energy for heating, for example, water for use in an apartment.

For example, the heater can be a so-called gas condensing boiler. The heater generally has at least one burner (with a combustion chamber) and a delivery device such as a fan, which delivers a mixture of fuel (gas) and combustion air (through a mixture duct of the heater) to the burner. The exhaust gas resulting from the combustion can then be routed through an (internal) exhaust pipe of the heater to an exhaust system (of a house). One or more heaters are connected to this exhaust system.

In order to ignite the mixture, a catalyst material such as platinum is placed in the gas-air mixture flow in the heater described here. Due to its properties, the catalyst material should enable the necessary activation energy to start the reaction without additional thermal energy (or ignition sparks).

According to an advantageous embodiment, it is proposed that the heater is set up to burn a fuel gas consisting of at least 90% hydrogen. The heater is particularly preferably suitable for burning hydrogen with ambient air from the building. In this context, the heating device can advantageously be designed as a so-called hydrogen condensing device.

According to a further advantageous embodiment, it is proposed that the catalyst material is at least partially formed with platinum. In particular, if the fuel gas consists of at least 90% hydrogen, platinum is particularly preferred as the catalyst, since platinum, due to its properties, has the necessary activation energy to start the reaction of hydrogen and oxygen from the air without additional thermal energy (or ignition sparks) enables.

According to a further advantageous embodiment, it is proposed that the catalyst material be held in the interior of the combustion chamber. For example, the catalyst material can be held in the form of a rod or a wire in an interior of the combustion chamber.

Alternatively or cumulatively, it can be provided that the catalyst material forms part of an inner surface of the combustion chamber. In this context, the catalyst material can, for example, be applied to an inner wall of the combustion chamber or integrated into the inner wall.

For example, a catalyst surface, such as a platinum surface, can be completely or partially incorporated into the burner material or additionally positioned above the burner surface (e.g. as a rod). In this way, it can be ensured in a particularly advantageous manner, without further auxiliary devices, that the gas stream flowing out is also burned when the gas valve is opened.

It is also proposed that a temperature sensor for monitoring the combustion is formed in the area of the catalyst material. In particular, the temperature sensor is arranged and / or set up in such a way that it can be used for flame monitoring. In this context, the temperature sensor can in particular be arranged and / or set up in such a way that it detects a temperature or temperature change of the Can measure catalyst material. Since the catalytic reaction is associated with heating of the catalytic converter, a conclusion about the combustion process can be drawn from the temperature or temperature change of the catalytic converter material, which is particularly advantageous for monitoring the combustion.

In other words, this can in particular also be described in such a way that, in order to monitor the combustion process, the part acting as a catalyst can be equipped with a temperature sensor which detects the heating of the catalyst associated with the catalytic reaction. This heating can then be reported back to a device control of the heater, for example. The temperature sensor can be embedded in or attached to the catalytic converter as an independent sensor.

It is also proposed that the temperature sensor be formed with the catalyst material. As an alternative to an independent sensor, the temperature-dependent electrical resistance of the catalyst material (e.g. platinum) itself can be used in a particularly advantageous manner in this context, in particular by means of R = U / I and by impressing a voltage (or a Current) and measuring the current (or voltage) to determine the temperature-dependent resistance and thus indirectly the temperature or temperature change of the catalyst material.

According to a particularly preferred embodiment, the catalyst material acting as an ignition catalyst is also designed as a measuring resistor. The use of a platinum measuring resistor is also particularly preferred in this context.

The catalyst material can also preferably be heated electrically. For electrical heating, the catalyst material can be subjected to an electrical voltage be. The catalyst material can (for this purpose) be connectable or connected to an electrical voltage source. In particular, the catalyst material can be electrically heated for an ignition process. In other words, this can in particular also be described in such a way that the catalyst material can be or is electrically heated to support an ignition process.

According to a further advantageous embodiment, it is proposed that the catalyst material be in the form of a wire which is preferably attached to a carrier layer. This can advantageously contribute to increasing the temperature sensitivity. Furthermore, the wire can be electrically heated for an ignition process.

To increase the temperature sensitivity, the catalyst material can, for example, be designed as a thin wire and applied, for example, to a ceramic carrier layer, preferably in meandering structures. A strip-shaped carrier can preferably be used. In this context, the meandering structure can also be applied to the top and bottom of the carrier strip. Furthermore, both sides can be evaluated electrically independently of one another. In this way, a one-sided drift of the sensitivity can be recognized in an advantageous manner by comparing the two values and, if necessary, the system can be brought into a safe error state if the deviation between the two measured values exceeds a tolerance limit.

1. a) Erfassen mindestens einer Temperatur oder Temperaturänderung des Katalysatormaterials,
2. b) Vergleichen der erfassten Temperatur oder Temperaturänderung mit zumindest einem Referenzwert oder Erwartungswert,
3. c) Beeinflussen des Betriebs des Heizgeräts in Abhängigkeit des Vergleichs aus Schritt b).

According to a further aspect, a method for monitoring the combustion in a heating device described here is proposed, comprising at least the following steps:

1. a) detecting at least one temperature or temperature change of the catalyst material,
2. b) comparing the recorded temperature or temperature change with at least one reference value or expected value,
3. c) influencing the operation of the heater as a function of the comparison from step b).

For detecting the at least one temperature or temperature change of the catalyst material, an electrical resistance or a change in the electrical resistance of the catalyst material can preferably be measured.

For monitoring the combustion, a reference value or expected value, such as a reference resistance value, can be stored in a device control of the heater. This can, for example, be determined at the factory as a fixed value and stored in the controller or (new) recorded after a longer period of standstill of the heater and used as a (new) reference resistance. In this way, drift effects of the measuring chain that occur over the service life of the device can be compensated for in an advantageous manner.

Furthermore, the catalyst material can be electrically heated in a heating phase. The detection of the temperature or temperature change of the catalyst material (according to step a)) is preferably interrupted in a heating phase of the catalyst material.

Preferably, during operation (ie during ignition or combustion), in particular during the starting process of the heater, the change in the electrical resistance of the catalyst material compared to the reference value is recorded in advantageously short time intervals (for example of a maximum of one second) and further preferably with a Compared expected value of the resistance over time. This expected value can also include a steady-state value for permanent burner operation and can optionally also vary as a function of the modulation specification of the heater.

If the measured resistance values do not correspond to any expected or permissible (or outside a tolerance range) heating, the fuel gas supply is usually interrupted (in step c) and the system is in particular locked switched off. This advantageously ensures that malfunctions in normal operation, caused for example by aging / passivation of the catalytic surface OR the supply of fuel gases that cannot be converted by means of the catalytic converter, are detected and a safety shutdown is initiated.

If the heating derived from the measured values occurs too quickly compared to the expected values, it can be concluded, for example, that there is a change in the thermal mass of the material used as a temperature sensor and / or the reaction temperature of the flame is higher than the expected value.

If the burner operation has exceeded a duration representing steady-state operation, in particular with (quasi) unchanged modulation specifications, and the measured value deviates from the expected value by an amount outside a tolerance range, a correction specification for the gas-air ratio can be made (in step c) overstoichiometric air ratio can be derived.

In this context, an excessively high steady-state measured temperature can indicate an air ratio that is too low compared to the expected value and / or a too low steady-state measured temperature may indicate an air ratio that is too high compared to the expected value. A detected deviation can be fed back (to the gas-air network) by means of a control signal. For example, (in step c) if the air ratio is too low, the fan speed or output of the delivery device can be increased and / or the gas valve opening position or the fuel gas volume flow can be reduced and (vice versa) if the air ratio is too high, the fan speed or output of the delivery device can be reduced and / or the Gas valve opening position or the fuel gas volume flow can be increased.

According to a further aspect, the use of a catalyst material for igniting a fuel gas predominantly containing hydrogen and for monitoring the combustion of the fuel gas in a heater is proposed. In this context, the heating device can be a heating device described here.

The details, features and advantageous configurations discussed in connection with the heating device can correspondingly also occur in the method and / or use presented here, and vice versa. In this respect, reference is made in full to the statements made there for a more detailed characterization of the features.

The invention will now be explained in detail with reference to the figures.

Figur 1:

beispielhaft und schematisch ein hier beschriebenes Heizgerät, und

Figur 2:

beispielhaft und schematisch einen Ablauf eines hier beschriebenen Verfahrens.

They represent:

Figure 1:

by way of example and schematically a heater described here, and

Figure 2:

an example and schematic of a sequence of a method described here.

Figure 1 shows by way of example and schematically a heater 1 described here for a building, in which a fuel gas-air mixture flow 2 is fed into a combustion chamber 3 and ignited there, the heater 1 being set up to burn a fuel gas containing predominantly hydrogen and to ignite the Fuel gas-air mixture, a catalyst material 4 is arranged in the heater 1. By way of example, the heater 1 is provided and set up here for burning a fuel gas consisting of at least 90% hydrogen. The burned fuel gas-air mixture can be discharged from the combustion chamber 3 via an exhaust gas flow 7.

Furthermore, the catalyst material 4 is here, for example, at least partially formed with platinum. In addition, the catalyst material 4 is here, for example, in the interior of the combustion chamber 3 held. Alternatively, it can be provided, for example, that the catalyst material 4 forms part of an inner surface of the combustion chamber 3.

A temperature sensor for monitoring the combustion is formed in the area of the catalyst material 4. For this purpose, the temperature sensor is formed with the catalyst material 4 (itself). For this purpose, the catalyst material 4 can be formed, for example, in the form of a wire 5 which is fastened to a carrier layer 6, for example. According to the example shown here, the ignition catalytic converter can thus function particularly advantageously at the same time as a platinum measuring resistor.

Figure 2 shows an example and schematically a sequence of a method described here. The method is used to monitor the combustion in a heater 1 described here. The sequence of steps a), b) and c) shown with blocks 110, 120 and 130 is exemplary and can thus be run through at least once in a regular operating sequence. In addition, steps a) to c) can also run at least partially in parallel or simultaneously.

In block 110, according to step a), at least one temperature or temperature change of the catalyst material 4 is recorded. In block 120, according to step b), the recorded temperature or temperature change is compared with at least one reference value or expected value. In block 130, according to step c), the operation of the heater 1 is influenced as a function of the comparison from step b).

This also shows an example of the use of a catalyst material 4 for igniting a fuel gas containing predominantly hydrogen and for monitoring the combustion of the fuel gas in a heater 1.

Furthermore, the catalyst material 4 can be electrically heated. The catalyst material 4 can thus be electrically heated in a heating phase, for example for (targeted) support of an ignition process. In the heating phase of the catalyst material 4, the detection of the temperature or temperature change of the catalyst material 4 can advantageously be interrupted.

A heater, a method and a use are thus specified which are suitable for the ignition and monitoring of hydrogen-rich fuel gases and in particular reduce or even overcome the disadvantages of the prior art.

List of reference symbols

1

heater

2

Fuel gas-air mixture flow

3

Combustion chamber

4th

Catalyst material

5

wire

6

Carrier layer

7th

Exhaust gas flow

Claims (15)

Heating device (1) for a building, in which a fuel gas-air mixture flow (2) is fed into a combustion chamber (3) and ignited there, characterized in that the heating device (1) is set up to burn a fuel gas predominantly containing hydrogen, that a catalyst material (4) is arranged in the heater (1) to ignite the fuel gas-air mixture, that a temperature sensor for monitoring the combustion is formed in the area of the catalyst material (4) and that the temperature sensor is formed with the catalyst material (4) is. Heater (1) according to claim 1, characterized in that the heater (1) is set up to burn a fuel gas consisting of at least 90% hydrogen. Heater (1) according to claim 1 or 2, characterized in that the catalyst material (4) is at least partially formed with platinum. Heater (1) according to one of Claims 1 to 3, characterized in that the catalyst material (4) is held in the interior of the combustion chamber (3). Heater (1) according to one of Claims 1 to 3, characterized in that the catalyst material (4) forms part of an inner surface of the combustion chamber (3). Heater (1) according to one of the preceding claims, characterized in that the catalyst material (4) acting as an ignition catalyst is also designed as a measuring resistor. Heater (1) according to Claim 6, characterized in that the measuring resistor is a platinum measuring resistor. Heater (1) according to one of the preceding claims, characterized in that the catalyst material (4) can be heated electrically. Heater (1) according to one of the preceding claims, characterized in that the catalyst material (4) is in the form of a wire (5). Heater (1) according to Claim 8, characterized in that the wire (5) is attached to a carrier layer (6). Heater (1) according to Claim 9 or 10, characterized in that the wire (5) can be electrically heated for an ignition process. Method for monitoring the combustion in a heating device (1) according to one of the preceding claims, comprising at least the following steps: a) detecting at least one temperature or temperature change of the catalyst material (4), b) comparing the detected temperature or temperature change with at least a reference value or expected value, c) influencing the operation of the heater (1) as a function of the comparison from step b). Process according to claim 12, wherein the catalyst material (4) is electrically heated in a heating phase. Method according to Claim 13 or 14, the detection of the temperature or temperature change of the catalyst material (4) being interrupted in a heating phase of the catalyst material (4). Use of a catalyst material (4) for igniting a fuel gas containing predominantly hydrogen and for monitoring the combustion of the fuel gas in a heater (1).

Images