Apparatus and method for measuring calorific value

A calorific value measurement apparatus comprising:

• a measurement unit configured to acquire a first value serving as a thermal conductivity index and a second value serving as a thermal diffusivity index, with respect to a fuel gas to be measured, at a first temperature, a second temperature, and a third temperature that are different from each other;
• a change rate calculation unit configured to calculate a temperature change rate κ1 of the first value between the first temperature and the second temperature, measured by the measurement unit, a temperature change rate κ2 of the first value between the second temperature and the third temperature, a temperature change rate α1 of the second value between the first temperature and the second temperature, and a temperature change rate α2 of the second value between the second temperature and the third temperature;
• and
• a calorific value calculation unit configured to calculate a calorific value of the fuel gas through a calorific value calculation formula in which the κ1, κ2, α1, and α2 serve as explanatory variables and the calorific value serves as an object variable,
• wherein the calorific value calculation formula is a regression formula obtained through acquiring the first value and the second value, with respect to each of four or more fuel gases the calorific value of which is known, at the first temperature, the second temperature, and the third temperature that are different from each other, acquiring the temperature change rate κ1 of the first value between the first temperature and the second temperature, the temperature change rate κ2 of the first value between the second temperature and the third temperature, the temperature change rate α1 of the second value between the first temperature and the second temperature, and the temperature change rate α2 of the second value between the second temperature and the third temperature, with respect to the first value and the second value of each of the fuel gases, and utilizing relations between the κ1, κ2, α1, and α2 of each of the fuel gases serving as the explanatory variables, and the calorific value of each of the known fuel gases serving as the object variable.