The Wobbe Index is said to be gross or net according to whether the calorific value uses is the gross or net calorific value.

Based on the gross calorific value and calculated for 0 °C.

 Heat capacities used were at constant pressure (

The thermal conductivity and the density are constants.

This recovers the silicone oil in the heat generating chamber (7), whereby the heating capacity is reduced.

cair is the specific heat capacity of air at constant pressure and density [kWh/(m3 K)]

to get the specific heat capacity at constant volume:

The constant -- is the critical exponent associated with the heat capacity.

The constant α is the critical exponent associated with the heat capacity.

is the heat capacity at constant volume, V {\displaystyle V}

The constant α is the critical exponent associated with the heat capacity.

For semi-caloric measurement the density, viscosity, thermal conductivity and heat capacity are used in the calculation.

The constant -- is the critical exponent associated with the heat capacity.

CV is the heat capacity at constant volume of the gas

The other factor is C, or the heat capacity, which depends on the material.