Method and system for determining the calorific value of a fuel gas in a gas network section and its use

Abstract

A method for determining a calorific value of a fuel gas in a gas network section for use in gas billing of consumers (102, 202a, 202b, 300) in the gas network section, the method comprising: a) Determining (S101) a calorific value of a fuel gas (B V ) by at least one consumer (102, 202a, 202b, 300) in the gas network section; b) transmitting (S102) the calorific value determined in step a) (B V ) and position data (P) of the at least one consumer (102, 202a, 202b, 300) to a central unit (101, 201); c) determining (S103) the calorific value of the fuel gas in the gas network section (B Z ) by the central unit (101, 201) based on the transmitted calorific value (B V ) and the position data (P); and d) Outputting (S104) the calorific value of the fuel gas in the gas network section (B Z) by the central unit (101, 201) for use in gas billing of consumers (102, 202a, 202b, 300) in the gas network section, characterized in that the at least one consumer (102, 202a, 202b, 300) is a gas boiler and in step a) the calorific value of the fuel gas (B V ) is determined by the at least one consumer (102, 202a, 202b) based on a relationship between the degree of modulation, heat load and air mass flow; or in step a) the calorific value of the fuel gas (B V ) by the at least one consumer (102, 202a, 202b) is determined on the basis of a relationship between heat output and efficiency.

Description

TECHNICAL FIELD

[0001] The invention relates to a method and a system for determining a calorific value of a fuel gas in a gas network section for use in gas billing for consumers in the gas network section, wherein the calorific value of the fuel gas for the gas network section can be determined safely and reliably and the determined value can be used for gas billing for consumers in the gas network section. TECHNICAL BACKGROUND

[0002] An object of the invention is to provide a method and a system which makes it possible to determine a calorific value of a fuel gas in a gas network section in a simple, safe and reliable manner, so that the determined value can be used for a gas billing of the consumers in the gas network section.

[0003] The calorific value of a fuel gas carried in a gas network section depends heavily on its composition. For example, depending on their type and proportion, additional gases can significantly influence the quality and thus the calorific value of the base gas carried in the gas network, and thus also the operation and consumption of appliances, i.e., consumers such as gas burners or gas boilers. The proportion of an additional gas in the fuel gas can fluctuate significantly within gas network sections, both regionally and over time, and thus also significantly influence the calorific value of the fuel gas, both regionally and over time.

[0004] Motivated by long-term CO2 emission reductions, for example, the injection of climate-neutrally produced hydrogen as an additional gas into the existing natural gas network is planned, with volume fractions of up to 40% by volume. However, the combustion properties of natural gas and hydrogen differ significantly.

[0005] Against this background, knowledge of the calorific value of a fuel gas carried in a gas network section, especially at different points in time, is desirable.

[0006] EP 2 450 704 B1, for example, describes a method for determining the calorific value of fuel gas, in particular natural gas, in gas networks, in particular in regional or distribution networks with at least two feed-in points, a plurality of network nodes and a plurality of exit points, wherein a) the calorific values ​​and quantities are measured at the feed-in points of the gas network, b) the quantities are estimated and summed at the exit points of the gas network on the basis of load profiles according to corresponding equations, c) the values ​​determined in each case are fed to an evaluation unit together with topological data of the gas network and the calorific values ​​are determined mathematically at at least one exit point.

[0007] EP 3 287 750 B1, for example, describes a gas metering system and a calorific value estimation method. The gas metering system is configured to estimate a calorific value of a gas passing through a first gas meter and a calorific value of a gas passing through a second gas meter provided separately from the first gas meter. The estimation is based on the calorific value of the gas from the first gas meter, which is arranged at a predetermined distance from the second gas meter along a gas supply line.

[0008] DE 10 2018 106 576 A1, for example, describes a method for determining gas consumption in a gas network with changing gas quality, comprising at least one metering device for recording at least one gas volume flow, wherein one or more local gas feed points are provided in the gas network. At least one current gas quality is determined in a network section of the gas network, wherein at least one consumption point in the network section draws a gas volume flow. At least the current gas quality of the gas in the network section is transmitted to a data center. The gas volume flow consumption of the at least one consumption point is determined using its metering device. The current consumption is transmitted to the data center based on time-accurate meter readings from the metering device.The current calorific value is determined based on the gas quality in the network section and at least the time-accurate calorific values ​​are linked to the meter readings at the point of consumption.

[0009] And FR 3 030 034 A1, for example, describes a gas meter for customer installation in a gas distribution network, comprising a line with a gas inlet opening and a gas outlet opening, a unit for measuring a quantity of gas circulating in the line, an analysis unit for the gas flowing in the channel in order to determine at least a partial composition thereof, and a data transmission unit which is connected to the analysis unit and arranged to transmit an identifier and analysis data, and at least one data acquisition unit separate from the measuring device.

[0010] Further generic methods are described, for example, in DE 10 2019 115 973 A1 and DE 10 2013 106 987 A1. SOLUTION TO THE PROBLEM

[0011] The above-mentioned object is achieved according to a first aspect of the invention by a method having the features of independent claim 1, and according to a second aspect of the invention by a system having the features of independent claim 10. The dependent claims are directed to particular embodiments of the invention. Further aspects of the invention will become apparent from the drawings and the description of exemplary embodiments.

[0012] The term "consumer" used herein refers to the consumption of fuel gas from a section of the gas network. Consumers can therefore include, for example, gas burners, gas boilers, or fuel cell modules. In the following, the term "device" is also used synonymously with the term "consumer."

[0013] The term "fuel gas" used herein refers to the fuel gas carried in a gas network section. This can be, for example, natural gas as the base gas, but also a proportionate mixture of natural gas and one or more additional gases, such as hydrogen, nitrogen, methane, sulfur, carbon monoxide, carbon dioxide, or propane.

[0014] In other words, determining the calorific value can also be described as balancing fuel energy. For example, by evaluating internal data points, the fuel energy Q [kWh] can be calculated as follows: The basis for the calculation is the degree of modulation [%]. Characteristic maps within a control device, such as a gas burner control unit (GFA), result in a linear relationship between the degree of modulation [%], heat load [kW], and air mass flow [g / s]. The fuel energy [kWh] is calculated by integrating the modulation [%] and thus the heat load [kW] over time.

[0015] The modulation level is specified, for example, by a boiler controller or a drinking water controller. This results in a setpoint specification for the air mass flow [g / s] and for the IO current setpoint [point]. The linear relationship between the modulation level and heat load only applies as long as the device is operated at the nominal air mass flow [g / s] and nominal lambda [-]. The reference variable for lambda is an IO current-based control. Based on empirical values, there is a lambda scatter of + / - 1 lambda-tenth under normal operating conditions. This scatter results, among other things, from aging of the IO electrode and other influencing factors. This results in a tolerance for the calculated fuel energy [kWh] of approximately + / - 2%.

[0016] As already explained, the determination of the calorific value can also be described as a balancing of fuel energy.

[0017] For example, the balancing can be carried out by determining the heat output QH [kW] and calculating the efficiency η using the following relationship: ηhs=outputinput=m×cp×dTVGas×GCV where: m = mass flow of heat transfer medium [kgh] cp = specific heat capacity of heat transfer medium [kJkg∗K] dT = temperature difference of heat transfer medium [K] V Norm_Gas = Standard volume flow of fuel gas [m3h] GCV=defHs = gross calorific value [kJm3]

[0018] The heat output is measured by an internal flow sensor, as well as the flow temperature (boiler temperature) and the return temperature (internal temperature in the flow sensor). The density and specific heat capacity are stored in support tables.

[0019] The efficiency η is calculated analogously to the combustion efficiency method. Starting with a maximum efficiency of 100%, the flue gas loss and the radiation loss are deducted. ηhs=100−qa,hs−qs

[0020] The exhaust gas loss qA,hs is the sum of sensible and unused latent heat content. The exhaust gas temperature is used to calculate the sensible portion. Furthermore, the exhaust gas mass flow is calculated based on the modulation level and the nominal lambda with the tolerances outlined above.

[0021] The latent portion of the exhaust gas loss describes the energy content that is not credited to the output in the form of heat through condensation. Direct measurement of this latent portion is not possible; therefore, the method uses a relationship between the average temperature in the heat exchanger, the degree of modulation, and a stored characteristic map for the degree of condensation.

[0022] To quantify the radiation loss qs, the boiler temperature and the modulation degree are used.

[0023] Determination of calorific value hs output=VNorm*hs hs=output / VNorm V Norm derived from control of the gas valve

[0024] The calorific value fundamentally depends on the properties of the fuel gas supplied in a gas network section. For example, a supplementary gas added proportionally to natural gas as the base gas can significantly influence the calorific value. The type of supplementary gas is not restricted by the invention. The supplementary gas can, for example, be selected from a group consisting of hydrogen, nitrogen, methane, sulfur, carbon monoxide, carbon dioxide, and propane.

[0025] The proportion of an additional gas in the fuel gas in gas network sections can vary significantly not only regionally but also over time and thus also have a strong influence on the calorific value of the fuel gas regionally and over time.

[0026] In a preferred embodiment, step a) of the method according to the invention can therefore be performed at least once within a predetermined time period Δt. The predetermined time period Δt is not limited according to the invention and can be based on empirical values ​​regarding the temporal fluctuations in the gas composition in the respective gas network section. In this way, however, a safe, reliable, and time-accurate determination of the calorific value of the fuel gas in the gas network section is possible.

[0027] In a further preferred embodiment, step a) of the method according to the invention can be performed two or more times within the predetermined time period Δt. By determining the calorific value of the fuel gas by the at least one consumer at two or more points in time within the predetermined time period Δt, the accuracy and reliability of the determined calorific value of the fuel gas in the gas network section can be further improved.

[0028] The method according to the invention further comprises step b) of transmitting the calorific value determined in step a) and position data of the at least one consumer to a central unit.

[0029] In a preferred embodiment, the transmission of the calorific value determined in step a) and the position data of the at least one consumer can take place in real time to the central unit. The term "real time" is to be interpreted broadly herein. Real time refers to the time delay between the transmission of the calorific value by the at least one consumer to the central unit and the output of the determined calorific value by the central unit.

[0030] In a further preferred embodiment, information about a determination time of the calorific value of the fuel gas by the at least one consumer can additionally be stored in step a) and transmitted to the central unit in step b). A determination time can, for example, be a time. Since gas billing generally occurs at a later time than the determination of the calorific value in the gas network section, a time-precise allocation of the determined calorific value in the gas network section can be carried out in this way. Preferably, the calorific values ​​of the fuel gas determined by the at least one consumer at the two or more points in time can then be collected and transmitted to the central unit in step b) together with the position data of the at least one consumer and optionally the information about the determination time.

[0031] A central unit here means a unit for transmitting (sending and receiving), storing, and processing data. A central unit can therefore be, for example, a control room, a server, or a cloud. Consumers, but also producers, in a gas network section can advantageously form a network with the central unit. Alternatively, or additionally, a central unit can also be connected to multiple networks or clusters of consumers and / or producers. The networks or clusters can, for example, be assigned to different, regionally specific gas network sections.

[0032] In addition to the calorific value determined in step a), position data of the at least one consumer are also transmitted to the central unit in step b) of the method according to the invention.

[0033] In a preferred embodiment, the position data can be anonymized. For example, anonymized can mean that only the assignment of a gas connection to a section of the gas network is transmitted as position data.

[0034] In a further preferred embodiment, in step a), the calorific value of the fuel gas can be determined by two or more consumers, wherein in step b), the calorific values ​​determined in step a) and the position data of the two or more consumers can be transmitted to the central unit, and in step c), an average calorific value of the fuel gas in the gas network section can be determined by the central unit. Due to the large number of consumers / devices in the field, the safety and reliability of the calorific value of the fuel gas in the gas network section determined in step c) can also be increased in this way.

[0035] In a particularly preferred embodiment, the transmission of the calorific values ​​determined in step a) and the position data of the two or more consumers to the central unit can take place in real time.

[0036] In a further preferred embodiment, in step a) additional information about the time of determination of the calorific value of the fuel gas by the two or more consumers can be stored and transmitted to the central unit in step b).

[0037] Alternatively, or in addition to averaging the calorific values ​​to determine the average calorific value of the fuel gas, if there are a large number of calorific values ​​determined by consumers, statistical methods can also be applied in the central unit to determine the calorific value of the fuel gas in the gas network section. For example, outliers in the calorific values ​​determined by consumers can be disregarded, or weighted averaging can be performed by the central unit. This can further increase the accuracy of the determined calorific value of the fuel gas in the gas network section. Furthermore, according to a preferred embodiment, in step a), the calorific value of the fuel gas can be determined simultaneously by the two or more consumers.

[0038] Alternatively, according to a further preferred embodiment, in step a) the calorific value of the fuel gas can be determined by the two or more consumers in each case with a time delay.

[0039] In this context, "delayed" means that a first consumer can determine the calorific value of the fuel gas at one or more first points in time, whereas a second consumer can determine the calorific value of the fuel gas at one or more second points in time that are offset from the first points in time. The interval by which the calorific value of the fuel gas is determined is not limited according to the invention and will depend on the total number of consumers. However, the interval can be, for example, 30 minutes.

[0040] The method according to the invention further comprises the step c) of determining the calorific value of the fuel gas in the gas network section by the central unit based on the transmitted calorific value of the at least one consumer and the position data.

[0041] In a preferred embodiment, information about the nature of the gas network section can additionally be stored in the central unit. Then, in step c), the calorific value of the fuel gas in the gas network section can be determined taking into account the information about the nature of the gas network section. Information about the nature of the gas network section can, for example, be information about the grouping of devices, i.e., consumers, in the gas network section.

[0042] The method according to the invention further comprises the step d) of outputting the calorific value of the fuel gas in the gas network section by the central unit for use in gas billing of consumers in the gas network section.

[0043] A system according to the invention for determining a calorific value of a fuel gas in a gas network section for use in gas billing for consumers in the gas network section comprises a gas network section in which at least one consumer is located. The at least one consumer has a device for transmitting data and is configured to determine a calorific value of a fuel gas. For this purpose, the at least one consumer can, for example, have a control device. The system according to the invention also comprises a central unit.

[0044] In a preferred embodiment of the system according to the invention, the at least one consumer may additionally have a time measuring device.

[0045] In a further preferred embodiment of the system according to the invention, two or more consumers can be arranged in the gas network section, wherein the two or more consumers each have a device for transmitting data and are each configured to determine a calorific value of a fuel gas. The two or more consumers can furthermore each have a time-measuring device. SHORT DESCRIPTION OF THE CHARACTERS Fig. 1 to 4 schematically show embodiments of the method, as well as embodiments of the system. Fig. 1 shows a flowchart of an embodiment of a method for determining a calorific value of a fuel gas in a gas network section for use in gas billing of consumers in the gas network section. Fig. 2 shows a block diagram illustrating an embodiment of a system for determining a calorific value of a fuel gas in a gas network section for use in gas billing of consumers in the gas network section. Fig. 3 shows a block diagram illustrating another embodiment of a system for determining a calorific value of a fuel gas in a gas network section for use in gas billing of consumers in the gas network section. Fig. 4 shows a block diagram of a gas burner according to an embodiment of a consumer. DETAILED DESCRIPTION OF THE FIGURES AND PREFERRED EMBODIMENTS

[0046] Examples and embodiments of the present invention are described in detail below with reference to the accompanying figures. Identical or similar elements in the figures may be designated by the same reference numerals, although sometimes different reference numerals may be used.

[0047] It should be emphasized, however, that the present invention is in no way limited or restricted to the exemplary embodiments and their embodiment features described below, but further comprises modifications of the exemplary embodiments, in particular those which are encompassed by modifying the features of the described examples or by combining individual or several features of the described examples within the scope of protection of the claims.

[0048] Fig. 1 shows a flowchart of an embodiment of a method for determining a calorific value of a fuel gas in a gas network section for use in gas billing of consumers in the gas network section.

[0049] In step S101, the calorific value of a fuel gas in a gas network section is determined by at least one consumer. The calorific value of the fuel gas is determined in step S101 based on the consumer's control parameters.

[0050] In a preferred embodiment, in step S101, information about a determination time of the calorific value, for example a time of day, can also be stored by the at least one consumer.

[0051] By determining the calorific value of the fuel gas by at least one consumer, the method according to the invention advantageously eliminates the need for additional measuring points, measuring devices, or even modifications, such as gas meters. The method according to the invention thus allows for simple, safe, and reliable determination and efficient monitoring of the calorific value of the fuel gas in a gas network section.

[0052] Motivated by long-term CO2 emission reductions, the injection of climate-neutrally produced hydrogen as a supplementary gas into the existing natural gas network is planned, with volumetric shares of up to 40 vol. Hydrogen differs significantly from natural gas as a base gas in its properties. For example, hydrogen has a lower calorific value per volume than natural gas. This means that to achieve comparable performance, the volumetric flow of fuel gas must be increased when hydrogen is added. Furthermore, the combustion reaction kinetics are different compared to pure natural gas, which significantly influences the flame speed, length, and geometry, as well as the flame temperature, ignition properties, and heat radiation.In particular, the determination of the calorific value of the fuel gas (base gas or base gas with proportional additional gas) by at least one consumer is important in view of possible regional-specific and / or time-dependent fluctuations in the hydrogen concentration in the gas network section and the resulting potentially strongly varying calorific value of the fuel gas.

[0053] In a preferred embodiment, the calorific value of the fuel gas can be determined in step S101 by the at least one consumer based on a relationship between the degree of modulation, the heat load and the air mass flow if the at least one consumer is a gas boiler.

[0054] Alternatively, according to a further preferred embodiment, if the at least one consumer is a gas boiler, the calorific value of the fuel gas can also be determined in step S101 based on a relationship between heat output and efficiency.

[0055] In step S102, the calorific value of the fuel gas determined in step S101 and the position data of the at least one consumer are then transmitted from the at least one consumer to a central unit. In a preferred embodiment, the calorific value determined in step S101 and the position data of the at least one consumer can be transmitted to the central unit in step S102 in real time. In a further preferred embodiment, the position data can be anonymized, for example, only comprising the assignment of a gas connection to an area of ​​the gas network section. In a further preferred embodiment, the information stored by the at least one consumer at the time the calorific value of the fuel gas was determined can also be transmitted to the central unit in step S102.

[0056] The method further comprises step S103 of determining the calorific value of the fuel gas in the gas network section by the central unit based on the transmitted calorific value and the position data. This can be done in particular by linking the calorific value of the fuel gas determined by the at least one consumer with the transmitted position data. Preferably, in step S103, the calorific value of the fuel gas in the gas network section can be determined by the central unit additionally taking into account the information on the time of determination of the calorific value of the fuel gas by the at least one consumer. In this way, a connection can be established between the determination time and the calorific value of the fuel gas in the gas network section, thus enabling gas billing at a precise time.

[0057] In a further preferred embodiment, information about the nature of the gas network section can additionally be stored in the central unit. Then, in step S103, the calorific value of the fuel gas can be determined taking into account the information about the nature of the gas network section. Information about the nature of the gas network section can, for example, be information about the grouping of devices, i.e., consumers, in the gas network section.

[0058] The method further comprises step S104 of outputting the calorific value of the fuel gas in the gas network section determined in step S103 by the central unit for use in gas billing of consumers in the gas network section.

[0059] As already explained, the composition and thus also the calorific value of a fuel gas conducted in a gas network section can fluctuate over time. In a preferred embodiment, step S101 can therefore be performed once within a predetermined time period Δt. According to another preferred embodiment, step S101 can also be performed two or more times within the predetermined time period Δt. The predetermined time period Δt is not limited according to the invention, but can be, for example, 24 hours.

[0060] In a further preferred embodiment, the calorific value of the fuel gas can be determined in step S101 by two or more consumers and in step S102 the calorific values ​​can then be transmitted to the central unit together with the associated position data.

[0061] In a preferred embodiment, the transmission of the calorific values ​​determined in step S101 and the position data of the two or more consumers to the central unit in step S102 can take place in real time.

[0062] In a further preferred embodiment, information about the time of determination of the calorific value of the fuel gas by the two or more consumers can additionally be stored in step S101 and transmitted to the central unit in step S102.

[0063] From the transmitted calorific values ​​and position data and optionally the information about the time of determination of the calorific values, an average calorific value of the fuel gas in the gas network section can then be determined by the central unit in step S103.

[0064] In a further preferred embodiment, the calorific value of the fuel gas can be determined simultaneously by the two or more consumers in step S101. Alternatively, according to a further preferred embodiment, the calorific value of the fuel gas can also be determined at different times by the two or more consumers.

[0065] Fig. 2 shows a block diagram illustrating an embodiment of a system for determining a calorific value of a fuel gas in a gas network section for use in gas billing of consumers in the gas network section.

[0066] The system 100 comprises a consumer (V) 102 and a central unit (Z) 101. The consumer 102 is located in a gas network section assigned to the central unit and has a device for determining the calorific value of a fuel gas, as well as a device for transmitting data (IP interface). The consumer 102 can also have a time measuring device, for example, to define time intervals for determining the calorific value. The consumer 102 can also have a measuring sensor system.

[0067] By means of the device for determining the calorific value, the consumer 102 determines a calorific value B V of the fuel gas. The calorific value B V is transmitted together with the position data P of the consumer 102 to the central unit 101. The central unit 101 then determines based on the calorific value B Vand the position data P, the calorific value Bz of the fuel gas in the gas network section in which the consumer 102 is located. The central unit 101 then outputs the calorific value of the fuel gas Bz for use in billing the consumers in the gas network section. This can be done, for example, via a push notification to the consumers in the gas network section or the respective gas supplier, or by making the determined calorific value available for retrieval by the consumers in the gas network section or the respective gas supplier.

[0068] Fig. 3 shows a block diagram illustrating another embodiment of a system for determining a calorific value of a fuel gas in a gas network section for use in gas billing of consumers in the gas network section.

[0069] In contrast to the Fig. 2, the system 100 shown in Fig. The system 200 shown in Figure 3 comprises two consumers V1, 202a and V2, 202b, each with a device for determining the calorific value of a fuel gas and a device for transmitting data. It should be noted here that the system is not limited to two consumers; the number of consumers will depend on the design of the respective gas network section.

[0070] As in Fig. 3, a calorific value B V by the two consumers 202a and 202b and transmitted together with position data P to the central unit 201. The central unit 201 then determines an average calorific value of the fuel gas B Z,M from the obtained, individually determined calorific values ​​B V in conjunction with the respective position data P. In a preferred embodiment, the average calorific value B Z,Malso taking into account information stored in the central unit 201 on the nature of the gas network section.

[0071] The average calorific value B Z,M is then output 203 by the central unit 201 for use in gas billing of consumers in the gas network section.

[0072] Fig. 4 shows a block diagram of a gas burner according to an embodiment of a consumer.

[0073] The gas burner 300 has a combustion chamber 301 in which a combustion process can take place with the supply of an air-combustion gas mixture. An ignition electrode 302 extends into the combustion chamber 301. Optionally, an ionization electrode can also be provided in the gas burner 300, which also extends into the combustion chamber. An ionization electrode is generally used for flame monitoring.

[0074] The ignition electrode 302 is connected to a device for generating an ignition voltage 304 such that the ignition electrode 302 can be separated from the device for generating the ignition voltage 304. This can be done by a switch arrangement 303 connected between the ignition electrode 302 and the device for generating the ignition voltage 304. In particular, the switch arrangement 303 can be configured such that after the ignition electrode 302 is separated from the device for generating the ignition voltage 304, the ignition electrode 302 is connected as a passive electrode.

[0075] The gas burner 300 also has a measuring device 305. Using the measuring device 305, for example, the temperature of the flame at the electrode can be determined by utilizing the thermoelectric effect, thus measuring the flame temperature profile at a correspondingly set load value. For this purpose, the switch arrangement 303 is connected to the measuring device 305 and can receive signals from the measuring device 305.

[0076] The measuring device 305 is also connected to a control circuit 306. The control circuit 306 can be used to control the combustion in the gas burner 300 by means of a burner control 309. For this purpose, the burner control 309 has a valve control 310 for changing the fuel gas proportion in the air-fuel gas mixture, as well as a fan control 311 for varying the air proportion.

[0077] The control circuit 306, in particular, comprises a device for determining a calorific value 307. The device for determining the calorific value 307 is connected to the measuring device 305 and receives the measured values ​​for determining the flame temperature profiles, which were determined by means of the ignition electrode 302 in the combustion chamber 301. In the device for determining the calorific value 307, the flame temperature profiles are evaluated and the calorific value of the fuel gas is determined.

[0078] Based on the determined calorific value, a controlled variable for controlling combustion in gas burner 300 can be derived in control circuit 306. The controlled variable can, for example, be an adjusted air ratio λ and / or a changed volume flow. The addition of hydrogen, for example, shifts the maximum laminar flame speed to lower lambda values, and a higher volume flow is required for a performance comparable to pure natural gas.

[0079] The controlled variable is then transmitted by the control circuit 306 to the burner control 309, which can then control the combustion in the gas burner 300 accordingly or adapt it to the changed fuel gas via the valve control 310 and / or the fan control 311.

[0080] The device for determining the calorific value 307 is also connected to a data transmission device 308, by means of which the determined calorific value and position data of the gas burner 300 can be transmitted to a central unit, for example, a cloud. The data transmission device 308 can also receive data from the cloud. REFERENCE SYMBOL 100 System for determining the calorific value of a fuel gas 101 central unit 102 consumers 200 System for determining the calorific value of a fuel gas 201 central unit 202a First Consumer 202b Second consumer 300 gas burners 301 Combustion chamber 302 ignition electrode 303 Switch arrangement 304 Device for generating an ignition voltage 305 Measuring device 306 control circuit 307 Device for determining the calorific value of a fuel gas 308 Facility for transmitting data 309 Burner control 310 valve control 311 Fan control V Consumer P Position data B V calorific value of the fuel gas determined by the consumer B Z calorific value of the fuel gas in the gas network section determined by the central unit B Z,M Average calorific value of the fuel gas in the gas network section determined by the central unit

Claims

[1] A method for determining a calorific value of a fuel gas in a gas network section for use in gas billing of consumers (102, 202a, 202b, 300) in the gas network section, the method comprising: a) Determining (S101) a calorific value of a fuel gas (B V ) by at least one consumer (102, 202a, 202b, 300) in the gas network section; b) transmitting (S102) the calorific value determined in step a) (B V ) and position data (P) of the at least one consumer (102, 202a, 202b, 300) to a central unit (101, 201); c) determining (S103) the calorific value of the fuel gas in the gas network section (B Z ) by the central unit (101, 201) based on the transmitted calorific value (B V ) and the position data (P); and d) Outputting (S104) the calorific value of the fuel gas in the gas network section (B Z) by the central unit (101, 201) for use in gas billing of consumers (102, 202a, 202b, 300) in the gas network section, characterized by that the at least one consumer (102, 202a, 202b, 300) is a gas boiler and in step a) the calorific value of the fuel gas (B V ) is determined by the at least one consumer (102, 202a, 202b) based on a relationship between the degree of modulation, heat load and air mass flow; or in step a) the calorific value of the fuel gas (B V ) by the at least one consumer (102, 202a, 202b) is determined on the basis of a relationship between heat output and efficiency. [2] Method according to claim 1, characterized by that in the central unit (101, 201) additional information about a condition of the gas network section is stored and in step c) the determination of the calorific value of the fuel gas (B Z) taking into account the information on the nature of the gas network section. [3] Method according to claim 1 or 2, characterized by that the position data (P) of the at least one consumer (102, 202a, 202b, 300) are anonymized position data. [4] Method according to one of claims 1 to 3, characterized by that in step b) the calorific value determined in step a) (B V ) and the position data (P) of the at least one consumer (102, 202a, 202b, 300) are transmitted in real time to the central unit (101, 201). [5] Method according to one of claims 1 to 4, characterized by that in step a) additional information about a determination time of the calorific value of the fuel gas (B V ) are stored by the at least one consumer (102, 202a, 202b, 300) and transmitted to the central unit in step b). [6] Method according to at least one of claims 1 to 5, characterized by that step a) is carried out at least once within a given time period Δt. [7] Method according to claim 6, characterized by that step a) is carried out two or more times within the specified time period Δt. [8] Method according to at least one of claims 1 to 7, characterized by that in step a) the calorific value of the fuel gas (B V ) is determined by two or more consumers (102, 202a, 202b, 300), wherein in step b) the calorific values ​​(B V ) and the position data (P) of the two or more consumers (102, 202a, 202b, 300) are transmitted to the central unit (101, 201) and in step c) an average calorific value of the fuel gas in the gas network section (B Z,M ) is determined by the central unit (101, 201). [9] Method according to claim 8, characterized by that in step a) the calorific value of the fuel gas (B V) by which two or more consumers (102, 202a, 202b, 300) are determined simultaneously; or the calorific value of the fuel gas (B V ) by the two or more consumers (102, 202a, 202b, 300) is determined with a time delay. [10] A system (100, 200) for determining a calorific value of a fuel gas in a gas network section for use in gas billing of consumers (102, 202a, 202b, 300) in the gas network section, the system comprising: - a gas network section in which at least one consumer (102, 202a, 202b, 300) is arranged, wherein the at least one consumer (102, 202a, 202b, 300) has a device for transmitting data (308) and is designed to determine a calorific value of a fuel gas (B V ) to determine (307); and - a central unit (101, 201), characterized bythat the system (100, 200) is arranged to carry out a method according to at least one of claims 1 to 9. [11] System (100, 200) according to claim 10, characterized by that the at least one consumer (102, 202a, 202b, 300) additionally has a time measuring device. [12] System (100, 200) according to claim 11 or 11, characterized by that two or more consumers (102, 202a, 202b, 300) are arranged in the gas network section, wherein the two or more consumers (102, 202a, 202b, 300) have a device for transmitting data (308) and are each set up to determine a calorific value of a fuel gas (B V ) (307).

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