Abstract: Method for measuring and/or regulating a quantity of heat contained in a fuel gas, the calorific value of the fuel gas being used as an input parameter, in which method a) the fuel gas or a part-stream of the fuel gas is guided through a volumetric meter or a mass flow meter, and the volumetric flow rate or the mass flow rate is measured, b) the speed of sound of the gas is determined under first reference conditions, c) one of the measurement variables dielectric constant, speed of sound under second reference conditions, carbon dioxide content of the fuel gas, nitrogen content of the fuel gas or density under standardized conditions is recorded; and d) the quantity of heat supplied is derived from these parameters, together with the calorific value of the fuel gas, as a measurement variable or control variable.

Abstract: Noncombustive method of measuring the calorific value of fuel gas, wherein a) the speed of sound in the gas is determined under first and under second reference conditions and one of the parameters dielectric constant, speed of sound under third reference conditions or proportion of carbon dioxide in the fuel gas is measured and b) the calorific value is derived from these three parameters, wherein the steps a) and b) are preferably preceded by a plurality of measurement cycles in which step a) is carried out using a plurality of reference gases of known calorific value, a number corresponding to the number of measurement cycles of reference signal patterns determined from the ratio of the various measurement signals measured on the reference gases are stored with assignment to the known calorific values and the signal pattern from a future measurement cycle on fuel gas of unknown calorific value is compared with the reference signal patterns so as to assign a particular calorific value.