Ceramic Stoves (example of a Ceramic Stove), or Kakkelovn, were first designed in Scandinavia in 1767, and have been a feature of homes and palaces ever since. Using some ingenious designing, a fairly small amount of wood can heat a room (or several) for 24 hours.
What makes it so efficient is that the wood is burnt around 1000 degrees Celsius, which is enough to ensure the only combustion products are steam and carbon dioxide as all the smoke is burnt off too. A metal stove would be damaged at this temperature, and so has to burn at a lower, more inefficient temperature. The flue gases from this hot burn are then diverted into several channels in the masonry body above the stove, with the flames and gases travelling up and down 3 times before exiting in the chimney. By this time the gases are below 200 degrees, having lost most of the heat into the masonry bulk. From a 1 – 2 hour burn, the whole stove will radiate heat for 24 hours. They’re also not bad to look at!
It is well worth considering to use one of these of you’re building or renovating a house with sustainability in mind – one of these stoves would require in Britain between 300 and 400 willows at 2m spacing on a short rotation coppice, so around an acre or a bit less for those with land to spare. It’s not recommended to build one yourself – they’re fairly complex to get built right! A company like the Ceramic Stove Company in Oxford or similar are experienced in installing them, although in future it would be beneficial if local craftsmen knew how to build these and install them en masse.
For the rest of us and for cooking, a smaller Rocket Stove might be more appropriate. These also burn a small amount of wood – often twigs or waste – at very high temperatures to achieve maximum efficiency. Designed for arid countries with little fuel and with problems of smoke on homes, they can be built small and simple or more complex depending on the situation, as long as a few principles of dimensions are observed. This is a good site to start, but there are plenty of other variations (such as this camping version) on the internet.
If we are to survive and adapt to tough times coming as civilisation declines, we need these sort of ingenious designs, in this case for heating and cooking, to make the best use of scarce resources, and make as little impact as possible on the earth.
