Image credit: ILoveCob
Rocket Stoves: Simple, Efficient Wood Burners
Generally speaking, TreeHuggers are fans of efficiency, and we are obsessive about recycling. So you'd think we'd be all over a design that can be made from recycled materials, costs pennies, and can boil water quickly and efficiently with only a few twigs for fuel. Yet strangely, it seems we have covered very little about Rocket Stoves. Sure - there are posts on both the Envirofit Cookstove and the Turbocooker, both of which seem to follow similar principles - but it seems like we've not talked about the concept from which these designs stem. I'll make a start at correcting this oversight.
- Insulating everywhere around the fire except where heat passes the cooking pot.
- Ensuring a good flow of air into the firebox.
- Using thin wood and burning only small amounts at a time for complete combustion.
- Forcing hot air down narrow passages around the cookpot.
Here's a little more from the ever-informative Wikipedia about Rocket Stoves and their benefits:
Compared with open fire cooking methods still used in many areas of the world (sometimes known as 'three stone fire' - a small fire contained by three or more rocks such that a pot or pan can rest on the flames), this stove operates on about half as much fuel, and produces substantially less smoke. Furthermore, the design of the stove requires small diameter lengths of wood, which can generally be satisfied with small branches. As such, sufficient fuel for cooking tasks can be gathered in less time, without the benefit of tools, and ideally without the destruction of forested areas.
Because these qualities improve local air quality, and discourage deforestation, the rocket stove has attracted the attention of a number of Appropriate Technology concerns, which have deployed it in numerous third-world locales (notably, the Rwandan refugee camps). This attention has resulted in a number of adaptations intended to improve convenience and safety, and thus the size of the target audience. The Justa Stove, for example, is a cousin of the rocket stove adapted for indoor use and family cooking needs. While it contains a 'rocket elbow' (the working core of a Rocket Stove), it differs in that it contains a flat griddle surface and a simple smokestack.
I've seen rocket stoves built from many simple, recycled materials - from old tin cans to AC ducts. Below is a video from Aprovecho that sets out the basic construction method.