Wood gasification boilers represent the state-of-the-art when it comes to turning cordwood into heated water.
They rely on two-stage combustion where wood is heated in a primary chamber to a point where a chemical reaction called pyrolysis occurs. The pyrolitic gases released during this process are channeled into a secondary combustion chamber where they mix with jets of superheated air. The resulting combustion resembles a blowtorch both in appearance and sound (see Figure 1).