I'm building a batchbox rocket burner, cast from refractory insulating concrete, based on the designs of Peter van den Berg. Anyone interested in this type of wood burner should have a look at Peter's excellent website www.batchrocket.eu, which explains all about the principles and build details.
For people unfamiliar with the technology, rocket burners aim to burn wood in the cleanest, most efficient way by using an insulated burn chamber and a separate heat-riser where smoke and gases from the initial burn are super-heated and mixed with air to allow a secondary burn to occur. The secondary burn removes the unwanted products of wood burning, such as smoke particles and volatile creosotes, converting them to more heat.
My ultimate aim is to develop the burner to allow heating of hot water that I will feed into my domestic central heating system.