Fuel poverty is a fact of life for many people in developing nations. They’re often reliant on buying expensive kerosene or coal, or gathering wood and dung to burn over open fires. In countries which benefit from a lot of sunshine, solar cookers are a practical and low cost alternative to traditionally fuelled cookers. But if you live in an area which doesn’t have high levels of sunshine you’re going to be reliant on wood or coal. Fortunately there is a design of stove that is cheap to build and highly efficient, meaning that the fuel lasts longer than if it was burnt over an open fire.
A Rocket stove here is used to cook dinner
Rocket stoves are incredibly simple to build, and easy to operate. They consist of a chimney, with an elbow joint at the bottom of the stove. Fuel (generally wood), is pushed through the elbow opening into the bottom of the chimney, where it burns.
A few simple guidelines ensure the rocket stove operates at maximum efficiency. Firstly, the fuel should rest on a small shelf in the elbow. This encourages air to flow under the fuel as it burns, creating an updraft. Any smoke produced by the fuel also gets burnt, making the stove burn much hotter than with a standard design.
Secondly, only the tips of the fuel should be burnt; this reduces the amount of smoke, and conserves fuel. No excess heat is produced (which would happen if you burnt all the fuel at once) so the stove burns highly efficiently.
The cooking pot sits at the top of the chimney and all the heat goes into heating the pot; none is lost to the sides or open air, which is what happens on an open fire. In fact they’re around twice as efficient as an open fire.
Rocket stoves can be built out of any metal, and tin cans work fine. In fact you could build one next time you go camping. On a larger scale, large metal drums (like oil containers) work well.
Rocket stoves have many advantages. Because so little fuel is needed, it can often be gathered quickly from fallen twigs or branches, reducing the need for tree cutting equipment and at the same time reducing deforestation. The fuel burns hot, creates less smoke and therefore reduces pollution; and they can be built cheaply out of recycled metal cans.
There are downsides of course. The high temperatures produced by the stoves mean they don’t last long if made from thin metal cans; they can be a fire hazard in an enclosed space; and burning wood is never ideal if an alternative such as solar fuel is available. Rocket stoves are however an excellent, low cost method of heating food and they do have their place; for example they were used widely in Rwandan refugee camps, helping feed thousands of refugees who might otherwise have gone without food.