Heating value measurement with the RGQ 5 and RGQ 3 - information about thermal energy

A heating value measurement determines the lower heating value (Hi) of a fuel gas and, thus, the amount of usable heat released during complete combustion, without taking into account the heat of condensation of the water vapor contained in the exhaust gas. The calorific value is expressed, for example, in MJ/m³ or kWh/m³ and is an important parameter for evaluating gas quality and energy input in combustion and industrial processes.

At RMG, calorific value determination can be performed using gas quality analyzers such as the RGQ 5 and the portable RGQ 3 . The instruments operate without conventional combustion of the sample gas and measure relevant gas parameters, which can be used to determine the heating value, among other things. This makes them particularly suitable for applications where gas quality and energy content must be monitored continuously or flexibly, such as with natural gas, biogas, or varying gas compositions.

In addition to the lower calorific value (Hi), modern Heating value measurement also provides other key parameters such as calorific value (Hs), Wobbe index, standard density and the compressibility factor Z. These parameters enable precise gas energy analysis and form the basis for energy billing, network monitoring and the optimization of combustion processes in terms of control technology.

In industrial applications, the measured values are continuously recorded and integrated into higher-level control systems via digital interfaces, ensuring continuous monitoring of energy and volume flows. Our devices record this data in high resolution and provide it in a stable manner for reliable Heating value measurement, even with fluctuating gas qualities.

Heating value measurement records the energy content of a gas based on physical properties or the exact composition of the gas. Relevant parameters are recorded via sensors in a gas analyzer and evaluated in real time.

In practice, parameters such as calorific value and Wobbe index are also calculated to enable a complete assessment of the gas quality. Modern measuring methods also allow the combination of Gas Meters and Heating value measurement, so that both volume and energy flows are precisely recorded. Our devices carry out this evaluation continuously and reproducibly, enabling reliable Heating value measurement even with fluctuating gas qualities.

Various technical standards apply to the determination and calculation of energy-related gas parameters. DIN EN ISO 6976 describes the calculation of calorific value, net calorific value, density, relative density, and Wobbe index based on the known gas composition. Depending on the measurement system and application, additional calculation methods such as GPA 2172, as well as methods for determining thermodynamic gas properties and the compressibility factor, may be used.

For applications involving calibration and billing, the applicable legal and metrological requirements, as well as the approval status of the measurement system used, must also be taken into account. Which standards apply depends on the measurement method, the gas, the measurement task, and the intended use of the measured values.

The lower heating value (Hi) describes the amount of heat released during complete combustion, excluding the heat of condensation of the water vapor contained in the exhaust gas. The gross heating value (Hs ) additionally accounts for the heat that can be released during the condensation of this water vapor.

The lower heating value is therefore higher than the gross heating value for the same gas. Which parameter is used depends on the specific energy analysis, the process, and the application.

Continuous heating value measurement without combustion does not require the measurement gas to be burned inside the measuring device. As a result, no burner components, ignition systems, or exhaust gas ducts are needed, as may be required in traditional calorimetric methods. This can reduce maintenance requirements and support high measurement availability.

RMG’s RGQ systems measure characteristic physical properties of the gas and use them to determine relevant gas quality parameters. Depending on the instrument model, different sensor and measurement principles are used. Changes in gas composition can thus be continuously monitored and utilized for process monitoring, quality assessment, or energy-related analysis.

The measured values can be transmitted to higher-level control and monitoring systems via suitable interfaces. This allows changes in gas quality to be detected in a timely manner and taken into account in downstream processes.

In natural gas networks , heating value measurement is used to assess the energy content of the gas being transported or injected into the system. Changes in gas composition—such as those resulting from the injection of biomethane or the addition of hydrogen—can affect the energy content and other gas quality parameters.

In industrial combustion and process plants, calorific value data can be used to monitor energy input and adjust process or combustion controls in response to changes in gas quality. This supports stable and demand-driven process control.