There are many forms of "rocket stoves" around the world but the one thing in common is that they give off some ferocious heat from burning very little fuel, mainly wood.

The basic style I am showing here is the brick stove version in which you use around 16 to 20 bricks in a stack with a hole in the middle. Stick a gas ring on top of the pile of bricks, stick a bit of wood in the bottom and light. Hey presto a stand by cooking furnace.