A method includes the introduction of a first medium into the compartment through an inlet and the heating of the first medium when it is present in the inlet. The heating takes place through the use of a combustion arrangement that is arranged in the inlet and that comprises fuel. The heating, the use of the combustion arrangement, includes in turn the ignition of the fuel, combustion of the fuel, and the transfer of the combustion heat to the first medium that is present at the combustion arrangement in the inlet. The combustion arrangement, is arranged in a region in the inlet, which in turn is arranged outside of the direct passage of the first medium in and through the inlet, such that the ignition of the fuel, the combustion of the fuel and the transfer of combustion heat to the first medium take place in this region.