Top Light Upward Draught (tlud) Cook Stoves
(See the page ‘making tlud stoves‘ for details of how to make and use these stove).
Developed and implemented by Paul Anderson, amongst others, various programmes have distributed these stoves in Kenya, Haiti and other majority world countries where it is thought that efficient, clean burning stoves would be beneficial.
These stoves are also the place to start for westerners wanting to start producing biochar whilst using the heat in order to start reducing dependence on the energy supply companies.
They are not ideally suited for use indoors, although it is possible to use them in open fire places or under a flue. (They can be used in conjunction with heaters such as the all in 1 heater.
They are ideal as light, portable camping cook stoves and are can be used on porches and balconies, allotments, gardens and as barbeques (which cook with the wood gases and leave the biochar unburnt; the reverse of most barbeques).
Tlud stoves consist of an inner cylinder which has a ring of holes near the top and a base with a few holes in it. An outer cylinder, to which a fan is attached, directs the forced air through the holes in the inner cylinder. Most of the air is forced through the top ring of holes. Biomass is put into the inner cylinder and a fire is lit on top of this biomass. Once the fire is established the fan is turned on. Because the airflow into the bottom of the cylinder is restricted, the fire produces a lot of smoke (wood gas). This wood gas combusts at the top of the stove where it meets the incoming forced air.
Mixing air with the wood gas at the point of combustion has the effect of producing a beautifully clean flame which is a pleasure to sit near because of the absence of smoke.
Where these stoves have been implemented, trees are no longer cut down for firewood or charcoal production as only small sticks are required, illness due to smoke in living spaces is reduced as they burn very cleanly, smoke pollution is reduced, soil fertility is mantained and atmospheric carbon is sequestered as they produce biochar.
These stoves have been instrumental in bringing about these changes in majority world countries. In developed countries they are not generally used for indoor domestic heat production because they need emptying of biochar, refilling, lighting from the top and therefore do not easily fit under a flue pipe like conventional wood stoves.
The Biochar Rocket Stoves are more ammenable for indoor use in developed world countries as they can be kept permanently under a flue outlet pipe or heat exchanger and are lit from the front rather than the top.