Part 1 - Building a simple Rocket Stove / demo at Vida Verde
Part 2 - Rocket Stoves all over the World
Part 3 - Downdraft cooking stove with excess heat accumulator
After reading so much on Rocket Stoves and all the good properties they exhibit, we decided that we would design a wood burning cooking stove for use indoors. The basic Rocket Stove design doesn't have a chimney, so is only usuable outdoors. Besides that, a standard Rocket Stove only heats one pot. We wanted more. After further investigations on the net we found a Brazilian design made by a student in mechanical engineering for his dissertation project. Our design is loosely based on this design.
More or less at the same time we were reading a small German booklet entitled Einfälle statt Abfälle - Abwärmeofen. This is number five out of a series on ecological building from 1989(!) by Christian Kuhtz Verlag. Translated the title would be Ideas instead of waste - Rest heat stoves. From this booklet we got the idea to put a heat accumulator behind the cooking stove to gain the excess heat from the stove to be able to use this heat for space heating.
So we did, here you can see the result.
Of course you wouldn't want to heat the house in the middle of summer, so we made a control valve to be able to either let the smoke out into the chimney directly, or to have the smoke travel downwards and upwards again through the brick column to heat the room in wintertime.
In the explanatory picture below the smoke path is drawn with the valve in the "winter" position. You can also see that the sticks are lying on the grid, but the flames and gasses travel downwards through the grid before they can get up to burn up the gasses completely in the riser pipe below the cooking plate. The most heat is generated in this riser pipe. When burning "full throttle", the flames reach the far end left of the cooking plate. No smothering fire here! Like in an ordinary Rocket Stove you regulate the fire by the number of sticks in the fire.
The downdraft principle - the top-down position of the fire - makes for a constant composition of the fire. From top to bottom there always is:
fresh sticks, coals and at the bottom the flames. In this way the fresh sticks release their gasses more gradually
and the gasses travel through the coals first (where a lot of chemical reactions and changes take place!)
before finally being burned in the flames.
