THE WINIARISKI ROCKET STOVE

Figures from AricMcBay:http://www.inthewake.org/b1cooking.html

"It is easy to construct, and it uses low-cost materials. The rocket stove's main components are:

• Chimney: a metal box (such as a 5-gallon tin can) or pipe standing vertically and supporting the cooking vessel
• Fuel magazine: a short length of steel or ceramic pipe fitted horizontally into the base of a chimney
• Fuel shelf: a flat plate to hold the fuel clear of the bottom of the magazine to allow air to flow underneath
• Heat exchanger: a tubular metal shield that forces hot gases from the chimney to pass over the sides of the cooking vessel

The chimney and magazine are joined at a right angle, forming the 'rocket elbow', and it is at this junction that primary combustion occurs."http://en.wikipedia.org/wiki/Rocket_stove

-The heart of the stove is the rocket elbow;small pieces of wood/ twigs are fed on to the fuel shelf in the fuel magazine;wood burning occurs only at the elbow aided by the air flow as shown in the figure;this ensures complete burning of the wood and prevents production of smoke ;smoke is formed when adequate air[oxygen]is not available for burning;
-complete burning results in full release of heat energy from wood and high temperatures in the combustion chamber;the heat energy is conserved by the insulation around the combustion chamber and directly transferred to the vessel on the grate as shown in the figure to the right.;
-the pot skirt ensures heat transfer to the pot both at the bottom and the sides.

-A long combustion chamber prevents smoke but reduces heat to the pot; a short chamber provides more heat but may generate some smoke.
-the gap between the pot and the skirt should be around twelve millimeters to ensure efficient transfer of heat to the pot;heat escapes with a large gap;if the gap is too narrow it restricts air flow.
- wood burns only at the inner end and it should be pushed in as it gets whittled down in burning.
"This stove operates on about half as much fuel, and produces substantially less smoke., compared to the traditional stoves;the stove requires small diameter lengths of wood, small branches or twigs; sufficient fuel for cooking tasks can be gathered in less time, without the benefit of tools, and ideally without the destruction of forested areas."[wikipedia]
The insulation of the combustion chamber is crucial for conservation of the heat generated and several types of materials have been used to achieve this;
Based on these principles several stoves have been designed to cater to all segments of the users;a ready-made stove ENVIROFIT is available in souther states for prices varying from Rs.700 to 2800.we could also build stoves for as low Rs.50 to 100 using local material like in 'Good-stove' ; after a survey of improved stoves the World Bank stated that models that can be constructed by the people with local materials are the ones that are easy for adoption.Stand-alone models are the best for urban poor and for all rural areas.