METHOD FOR OPERATING A HEATING DEVICE, COMPUTER PROGRAM, STORAGE MEDIUM, CONTROL AND REGULATION DEVICE, HEATING DEVICE AND USE OF A SIGNAL

Description

[0001] The invention relates to a method for operating a heating device, a computer program, a storage medium, a control and regulating device and a heating device.

[0002] Heating appliances designed to burn gas, such as natural gas, often utilize the ionization effect of the flame to regulate the fuel-air mixture. This ionization effect is based on a change in the electrical resistance of the flame due to the free charge carriers released during combustion.

[0003] The combustion of hydrogen produces significantly fewer free charge carriers, making it more difficult to use the ionization effect to control the fuel-air mixture.

[0004] For example, DE 10 2004 055 716 C5 proposes including a temperature generated by a combustion device in the control of the combustion device.

[0005] GB 227 0748 A specifies a control system for a gas burner, whereby a burner temperature is used to control an air supply device of the heating appliance.

[0006] DE 100 4 270 C2 also proposes a combustion device and a method for controlling it, wherein a fuel-air ratio and a volume flow rate of a fuel-air mixture are controlled by means of a signal from a temperature sensor located in an area of ​​the burner, ensuring that it is completely within the main reaction zone of a developing flame.

[0007] German patent DE 198 13 313 A1 relates to a water heater with a gas burner. The fuel gas-air ratio can be regulated by means of a glow plug. To carry out the regulation procedure, the glow plug is supplied with a base voltage, which is lower than the ignition voltage, following the actual ignition process, whereby the current flow through the glow plug can be measured.

[0008] US Patent 3,282,324 A relates to a gas burner with an automatic ignition device and a heat detection system. For this purpose, an electrical ignition device is arranged in series with a gas valve actuator in a circuit, so that when the flame goes out and there is a corresponding drop in temperature and a change in the actuator's electrical resistance, the gas valve is closed.

[0009] WO 03 / 052320 A1 proposes flame monitoring, particularly for monitoring flame ignition. For this purpose, a glow plug can be subjected to an electrical voltage below the ignition voltage after an ignition process, and a current flow that allows conclusions to be drawn about the presence of a flame can be detected.

[0010] A disadvantage of the listed solutions is the slow response time of the temperature measurement. This necessitates a slower rate of power adjustment by the control system, which can lead to reduced user comfort, for example, during hot water preparation. Furthermore, the slow power adjustment rate can result in delayed detection of critical conditions, such as the flame going out in the heating appliance, thus compromising the operational reliability of the heating appliance.

[0011] Based on this, the object of the invention is to propose a method for operating a heating device and a heating device that at least partially overcomes the problems of the prior art described above. In particular, the proposed method should enable a safe and fast-acting control of a heating device.

[0012] The invention should also not significantly increase the complexity of a heating device, require only minor structural changes to a heating device, and allow for easy integration into an existing production process.

[0013] These problems are solved by the features of the independent claims. Further advantageous embodiments of the solution proposed here are specified in the dependent claims. In addition, the features specified in the claims are further detailed and explained in the description, which also presents further preferred embodiments of the invention.

[0014] This involves a method for operating a heating device, wherein the heating device has a temperature sensor arranged such that the temperature of a flame in the heating device can be detected. The method comprises at least the following steps: a) Heating the temperature sensor to a setpoint temperature value by means of an electric heater and maintaining the setpoint temperature value as a control variable by a controller, wherein the setpoint temperature value corresponds as closely as possible to an expected temperature of the flame of the heating device, b) Acquiring a signal from the temperature sensor, subsequently or at least partially in parallel with the execution of step a), c) Operating the heating device incorporating the signal from the temperature sensor acquired in step b), wherein the signal from the temperature sensor is incorporated into a control of the mixture composition of the heating device.

[0015] Steps a), b), and c) can be performed at least once in the specified order during normal operation. Steps a) and b) are executed at least partially simultaneously or in parallel. Advantageously, steps a), b), and c) can also be repeated at regular intervals to ensure reliable and precise control of the heating device. Typically, step a) can also be performed only once at the beginning of the process, and the temperature sensor can then be maintained at a temperature corresponding to the setpoint.

[0016] A method proposed here can be carried out according to the invention on a heating device and / or, in particular, on a control and regulating device of a heating device.

[0017] The heating appliance in question is, in particular, a gas-fired boiler designed to combust a fuel gas, especially hydrogen, with the addition of ambient air to generate heat energy, for example, to heat a heat transfer fluid in a heating circuit or to provide hot water. The heating appliance may specifically be a condensing boiler. It typically has a combustion chamber and a delivery system that supplies a mixture of fuel gas and combustion air to the combustion chamber. The combustion products can then be discharged through an exhaust system.

[0018] According to the invention, the heating device has a temperature sensor arranged such that the flame temperature of the heating device can be detected. For this purpose, the temperature sensor can be arranged in the combustion chamber of the heating device, in particular in a region of the combustion chamber where a flame forms during regular use.

[0019] The temperature sensor can be positioned in the flame core, base, or tip area of ​​the flame when the burner is in operation. The sensor could be attached to the burner itself or to a burner door; such a design can be easily integrated into existing assembly processes. The temperatures to be measured by the sensor can, for example, range from 100 °C to 1,500 °C.

[0020] The temperature sensor can be any type of temperature sensor that provides an electrical signal as a measure of its temperature. This signal can consist of, for example, a measurable electrical resistance, such as a measuring resistor like a platinum or silicon resistor, a thermistor (NTC), or a thermistor (PTC). The temperature sensor can also be a semiconductor temperature sensor that provides a directly processable electrical signal representative of the temperature.

[0021] The invention is used to operate a heating appliance, and its use advantageously provides an alternative to controlling a mixture composition based on the ionization effect of the flame, which is not applicable, for example, to the combustion of hydrogen. The method proposed here is fundamentally suitable for heating appliances designed to burn a fuel.

[0022] According to step a), the temperature sensor is heated to a set temperature value. This heating is achieved by an active or selectively activatable and deactivatable heat source, which is appropriately positioned for this purpose. The heat source is an electric heater. Heat transfer from the heat source to the temperature sensor can occur, for example, via thermal radiation and / or thermal conduction.

[0023] In step a), after the temperature sensor has been heated, its temperature is held (largely) constant at the target temperature value. Thus, a key aspect of the invention is to continuously heat the temperature sensor while the heating device is in operation, thereby reducing the influence of the temperature sensor's thermal mass.

[0024] Heating the temperature sensor to a target temperature value according to step a) can be achieved, for example, by operating an active heat source with a defined electrical power, thereby allowing the temperature sensor to reach a defined temperature (target temperature value). The active heat source can be a heating device located adjacent to or in the immediate vicinity of the temperature sensor.

[0025] According to an advantageous embodiment, the temperature sensor itself can also be the heat source. For example, in resistance-based temperature sensors (temperature sensors whose electrical resistance changes depending on the temperature), a current flowing through the temperature sensor can cause it to heat up. Advantageously, this embodiment eliminates the need for an additional heating element.

[0026] In step a), the target temperature value is reached and maintained as a controlled variable by a controller (control loop).

[0027] A setpoint temperature to which the temperature sensor is heated according to step a) can be a temperature above a resting temperature (heating power of the temperature sensor's heat source = 0), where the setpoint temperature corresponds as closely as possible to the expected flame temperature. Preferably, the setpoint temperature remains constant over the entire operating range (lambda, power) of the device and is particularly close to the highest resting temperature of the entire operating range. With regard to component aging and / or electrical energy consumption, a setpoint temperature that is (variably) adjusted over the operating range may be advantageous, always being close to the resting temperature of that operating point.

[0028] According to step b), a signal from the temperature sensor is acquired. The signal to be acquired can be any detectable signal from the temperature sensor that allows conclusions to be drawn about the temperature of a flame in the heating appliance. Knowing the flame temperature advantageously allows conclusions to be drawn about the quality of combustion. For example, a potentially extinguished flame in the heating appliance can be quickly detected based on the flame temperature, and appropriate measures, such as re-ignition or shutting off the gas supply, can be initiated.

[0029] In step b), the temperature sensor signal is a parameter or control signal for a controller (control loop) to regulate a setpoint temperature value of the temperature sensor. The control signal can be, in particular, electrical power or an applied electrical voltage and / or an electrical current flowing through the heating element. This configuration is especially advantageous for temperature sensors that are themselves a heat source. Examples of possible parameters include heating power, the electrical current, or the voltage applied to the temperature sensor.

[0030] In this context, it is expressly pointed out that during the execution of step b), several (different) signals from the temperature sensor can also be recorded and included in the operation of the heating device according to step c).

[0031] A controller for regulating the setpoint temperature can be, in particular, a proportional (P) controller, which offers a fast response time. Other controllers can also be used, especially a inversely proportional (PI) controller, to achieve, for example, a steady-state temperature sensor with precise control in addition to a fast response time.

[0032] According to step c), the heating appliance is operated using the temperature sensor signal acquired in step b). The temperature sensor signal is incorporated into the control of the fuel-air mixture. It is understood that further parameters can influence the operation of the heating appliance or the control of the mixture composition, such as at least one, preferably several, of the following: the mass flow rate of the fuel-air mixture supplied; the supply and return temperatures and / or volume flow rates of a heating circuit connected to the heating appliance; the outside temperature; the fan speed; the temperature of the supplied air mass flow; and the temperature of the supplied gas-air mixture. It is possible that the sensor system is also adapted accordingly, for example, combination sensors that provide multiple signals / data.For example, a temperature signal can be provided by the mass flow (temperature) sensor of the combustion air.

[0033] The integration of the signal into the operation of the heating appliance according to step c) can be achieved, for example, by comparing the signal detected in step b), which allows conclusions to be drawn about the temperature of the heating appliance's flame, with a reference value. If the signal detected in step b) is above the reference value, this may indicate an excessively high flame temperature, which could be related to an excessively high proportion of fuel in the mixture. As part of the mixture composition control, the proportion of fuel in the mixture can be reduced as a response, which may cause the signal detected in step b) to decrease towards the reference value. Similarly, a signal detected in step b) that is lower than the reference value may indicate an insufficient proportion of fuel in the mixture. This can be counteracted by increasing the proportion of fuel in the mixture.

[0034] According to an advantageous embodiment, when the heating device is operated according to step c), ignition of the heating device can be effected by the temperature sensor. For this purpose, the temperature sensor can, for example, be designed as a hot-surface igniter, i.e., as a resistance heater that can be heated to a temperature above the ignition temperature of the fuel-air mixture and, according to the invention, is heated to an expected flame temperature. This advantageously reduces the complexity of the heating device proposed here, since the ignition device, the temperature sensor, and a device for heating the temperature sensor can be implemented by only one component. For example, the temperature sensor can be a silicon nitride or a silicon carbide hot-surface igniter.

[0035] According to an advantageous embodiment, in step d) the temperature sensor signal can be checked. This check (plausibility check) can be performed, for example, by comparing a heating power output with a temperature signal from the temperature sensor. This is particularly useful when there is no flame, after operation has ceased and / or before ignition, because only ambient influences are present (ambient temperature of the temperature sensor). During operation, briefly increasing the heating power of the temperature sensor can be used to verify that the signal path from the heating element to the measurement signal reacts correctly to the change in heating power and that the control loop remains closed (test process).

[0036] Not according to the invention, in step a) the temperature sensor at an operating point of the heating device can be heated to various setpoint temperatures, and in step b) a signal from the temperature sensor can be acquired. The data thus acquired can advantageously be used for controlling the heating device and allow, for example, compensation for tolerances such as sensor drift, or an estimation of the mass flow rate of the fuel-air mixture flowing into the combustion chamber. Sensor drift is understood here as a (slow) change in the sensor signal at a constant temperature of the temperature sensor.

[0037] The determined pairs of signals (1. target temperature, 2. required heating power of the temperature sensor to reach the target temperature) can be compared with calibration data in conjunction with signals describing the operating point (all signals / parameters of the operation of the heating device as specified above), in particular fan speed and / or mass flow of the combustion air and / or mass flow of the gas-air mixture) in order to perform compensation.

[0038] According to an advantageous embodiment, the temperature sensor can be permanently maintained at a temperature above the ignition temperature of the heating device (or of the fuel-air mixture). This advantageously improves the safety of the heating device considerably, as ignition conditions are constantly present, allowing the flame to reignite immediately if it goes out, thus effectively preventing the escape of unburned fuel. The ignition temperature can be regularly set above 500 °C or 600 °C.

[0039] For the start-up process of the heating device, the temperature sensor is heated to a temperature above the ignition temperature of the combustion mixture, and subsequently, after detection of a flame from the heating device, the temperature of the temperature sensor can be set to a target temperature below the ignition temperature.

[0040] Another aspect is also proposed: a computer program comprising commands which, when the program is executed by a proposed control and regulation device, cause a proposed heating device to execute a procedure described herein.

[0041] Another aspect that is proposed is a machine-readable storage medium on which the computer program is stored.

[0042] The machine-readable storage medium is usually a computer-readable data carrier.

[0043] Another aspect is the proposal for a control unit for a heating appliance, designed to carry out the procedure presented here. This control unit can, for example, include or be equipped with a processor. In this context, the processor can, for instance, execute the procedure stored in the control unit's memory.

[0044] Another aspect is the proposal for a heating appliance with a control and regulation unit as presented here. This heating appliance is specifically a gas-fired appliance with a gas burner and a delivery system capable of supplying a mixture of fuel gas and combustion air to the gas burner. The heating appliance can be configured to burn hydrogen as the fuel gas.

[0045] The heating device has a temperature sensor arranged to detect the flame temperature of the heating device. The temperature sensor itself, or an electrical heating element, is configured to heat the sensor. The temperature sensor can be a resistance-based sensor and can be heated by applying an electrical voltage. A controller can be configured to regulate a parameter of the electrical power supply to the temperature sensor. This parameter can be, in particular, the electrical voltage or current by which the temperature sensor can be controlled to a defined temperature (setpoint temperature).

[0046] In a further advantageous embodiment, it is proposed that the temperature sensor can be heated by applying an electrical voltage and that a controller is provided to regulate a parameter of the electrical power supply to the temperature sensor. This parameter can be, in particular, the electrical voltage or the electrical current by means of which the temperature sensor can be controlled to a defined temperature (setpoint temperature).

[0047] The details, features, and advantageous configurations discussed in connection with the process may also occur in the computer program, storage medium, control unit, and / or heating device presented here, and vice versa. In this respect, full reference is made to the explanations provided therein for a more detailed characterization of the features.

[0048] This document presents a method for operating a heating device, a computer program, a storage medium, and a heating device that at least partially solve the problems described with reference to the prior art. In particular, the method and the heating device contribute to providing a safe and sufficiently fast-acting method for operating a heating device, which is also applicable to a heating device designed for hydrogen combustion. Advantageously, heating the temperature sensor reduces the influence of thermal mass on signal acquisition, thereby significantly increasing the response speed of the temperature sensor's signal acquisition.

[0049] Furthermore, the method can be implemented in a simple manner. For the proposed method to be implemented, a heating device only needs a temperature sensor, which can be located in an area where a flame regularly forms, and a way to actively heat it.

[0050] The details, features, and advantageous configurations discussed in connection with the process can also occur in the computer program, storage medium, control unit, and heating device presented here, and vice versa. In this respect, full reference is made to the explanations provided therein for a more detailed characterization of the features.

[0051] The invention and its technical context are explained in more detail below with reference to the accompanying figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments shown. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the situations described in the figures and combine them with other components and findings from the present description. It should be emphasized that the figures, and especially the depicted dimensions, are only schematic. They show: Fig. 1: a sequence of a procedure proposed here, Fig. 2: a heating device proposed here, and Fig. 3: a parameter profile that can be achieved when carrying out a procedure proposed here.

[0052] Fig. 1Figure 1 shows an exemplary and schematic representation of the sequence of a proposed method. This method is used to operate a heating device 2 and allows for the control of a mixture composition (fuel and combustion air) without utilizing the ionization effect of a flame 6 in the heating device 2. The sequence of steps a), b), and c), represented by blocks 110, 120, and 130, can occur during a regular process flow.

[0053] In block 110, according to step a), a temperature sensor 1 is heated. For this purpose, the temperature sensor 1 can, for example, be a resistance-based temperature sensor, so that by applying a voltage a current flows through the temperature sensor 1, accompanied by a conversion of electrical energy into heat energy at the electrical resistance of the temperature sensor 1, and thus by heating it.

[0054] According to an alternative embodiment, a heat source (for example, a current-carrying electrical resistor) can also be arranged in the immediate vicinity of the temperature sensor 1.

[0055] In block 120, a signal from temperature sensor 1 is acquired according to step b). For a resistance-based temperature sensor 1, the signal can be, for example, the electrical resistance of the temperature sensor 1, which can be determined and acquired based on the applied electrical voltage and the flowing electrical current.

[0056] In block 130, according to step c), the heating device 2 is operated using the signal recorded in block 120 (step b)).

[0057] Fig. 2 Figure 1 shows an exemplary and schematic representation of a heating device 2 proposed here. The heating device 2 has a control and regulating unit 8, which is set up to carry out a procedure proposed here.

[0058] The heating appliance 2 (e.g., a gas condensing boiler) is equipped with a burner system arranged in a combustion chamber 9. In this system, gas from a gas supply channel 13 and combustion air from an air intake channel 12 are combined in a mixture channel 11 (see mixture mixing 14) via a valve 7 upstream of a blower, which is represented here as an example of a conveying device 5. This mixture is then transported by the conveying device 5 via the mixture channel 11 to the combustion chamber 9, where combustion takes place. The exhaust gases produced by the combustion are routed through an internal exhaust pipe 10 to an exhaust system (not shown here).

[0059] In the combustion chamber 9, a temperature sensor 1 is arranged such that it can be positioned in or in the immediate vicinity of a flame 6 when the heating device 2 is in operation. The temperature sensor 1 can be a resistance-based temperature sensor that can be heated by applying an electrical voltage to perform step a) (block 110). According to step b) (block 120), the signal from the temperature sensor 1 can be acquired. Furthermore, according to step c) (block 130), the heating device 2 can then be operated using the signal from the temperature sensor 1 acquired in step b).

[0060] Fig. 3 This shows an exemplary and schematic parameter profile that can occur when carrying out a proposed procedure. Figure 3 Figure 1 shows two diagrams that illustrate the advantages of a method proposed here. The abscissa of both diagrams represents time t and is analogous in both diagrams.

[0061] The upper diagram shows a temperature signal ϑ sens 3 from a (non-actively heated) temperature sensor arranged in the vicinity of a flame 6 in a combustion chamber 9 of a heating device 2, according to the prior art. A loss of the flame 6 at time t V can be detected by a delayed decrease in the measured temperature ϑ sens.

[0062] The lower diagram shows a control signal 4 of an electrical power controller P el of an actively heated temperature sensor 1. Here, too, the flame 6 is lost at time t V. The control signal 4 of the electrical power controller P el reacts immediately after the loss of the flame 6 at time t V, in contrast to the temperature signal ϑsens 3 of a (non-actively heated) temperature sensor located in the vicinity of a flame 6 in a combustion chamber 9 of a heater 2. The significantly faster response time of the control signal 4 of the electrical power controller P el enables its use for controlling the heater 1, in particular for controlling the mixture composition of fuel and combustion air. Reference symbol list:

[0063] 1 Temperature sensor 2 Heater 3 Temperature signal (state-of-the-art temperature sensor) 4 Control signal (power control, actively heated temperature sensor) 5 Conveyor device 6 Flame 7 Valve 8 Control unit 9 Combustion chamber 10 Exhaust pipe 11 Mixture channel 12 Air intake channel 13 Gas supply channel 14 Mixture mixing

Claims

1. Method for operating a heating appliance (2) comprising a temperature sensor (1) arranged in such a way that the temperature of a flame (6) of the heating appliance (2) can be detected, comprising at least the following steps: a) heating the temperature sensor (1) to a target temperature value by means of an electric heater and maintaining the target temperature value as a control variable by means of a controller , wherein the target temperature value corresponds as closely as possible to the expected temperature of the flame (6), b) Detecting a signal from the temperature sensor (1) following or at least partially in parallel with the execution of step a), c) operating the heating appliance (2) taking into account the signal from the temperature sensor (1) detected in step b) , whereby the signal from the temperature sensor (1) is incorporated into a control of the mixture composition of the heating appliance (2) .

2. . Method according to claim 1, wherein, when the heating appliance (2) is operated according to step c), the heating appliance (2) is ignited by the temperature sensor (1).

3. . Method according to one of the preceding claims, wherein in step d) the signal from the temperature sensor (1) is checked.

4. . Method according to one of the preceding claims, wherein the temperature sensor (1) is heated in step a) by applying an electrical voltage to the temperature sensor (1) and is regulated to a target temperature value by a controller.

5. . Method according to claim 4, wherein in step b) a control signal from the controller is detected as a signal from the temperature sensor (1).

6. . Control and regulating device (8) for a heating appliance designed to combust a combustion mixture of combustion air and fuel, wherein the control and regulating device (8) is designed to cause the heating appliance (2) to carry out the method steps according to one of claims 1 to 5.

7. . Heating appliance (2), comprising a control and regulation device (8) according to claim 6 and at least one temperature sensor (1) arranged such that the temperature of a flame (6) of the heating appliance (2) can be detected, wherein the temperature sensor (1) itself or a heating device is designed to heat the temperature sensor (1), wherein the temperature sensor (1) being a resistance-based temperature sensor that can be heated by electric current, and a controller being designed to regulate a parameter of the electrical energy supply to the temperature sensor (1).

8. . Computer programme comprising instructions that cause a control and regulating device (8) according to claim 6 or a heating appliance (2) according to claim 7 to execute a method according to one of claims 1 to 5.

9. . Machine-readable storage medium on which the computer program according to claim 8 is stored.