We are happy to now offer two unique cookstoves to Kenyan families. To learn more about each stove, click the link to read the user manuals
How they work, why they work and the benefits over other cook stoves:
In 2012 Wisdom Stoves started producing and distributing the Malaika Jiko, while continuing research and designing the latest version, the M2. In August, 2013, after many hours of research, we started to produce and sell the M2. Since 2012, we have manufactured and distributed over 2000 stoves. These stoves are our variation of the t-char stove. To learn more about this stove visit Drtlud.com.
Nathan Puffer, co-founder of Wisdom Stoves, has been researching gasification stoves since 2009, and has designed nearly 20 fan assisted and naturally aspirated stoves in that time. His dedication to Wisdom Stoves began with his continual search to create a stove that fits the needs of the Kenyan people and works extremely well for the available fuel sources.
The Malaika jiko is a TLUD design; a top lit up-draft gasification cook stove. It is designed to burn biomass including wood, corn husks, cow dung, coffee husks, dried bio mass briquette, and other, as of yet unidentified fuels.
The Malaika jiko is placed on top of a 10” standard improved Kenya jiko (with ceramic insert). Make sure the fit is snug and secure. Doors on the two stoves should be aligned and open.
The ideal wood preparation is dried match box sized pieces of wood. It is common to see Kenyan residents using sticks about 8” long bundled together and placed vertically into the fire chamber. All of the wood used, including the starter wood should be as dry as possible. Wood preparation is important as green or wet wood will increase the possibility of smoke produced at the start.
Load the wood to just below the secondary air holes (4” below the top of the fire chamber). On top of the biomass used, starter wood (smaller pieces) should be placed. This starter wood should be rinsed in kerosene (paraffin). The amount of kerosene is only to act as an accelerant to start the fire.
Light the sticks on top of the Malaika jiko. The desire is to light the entire top surface of the area at the top of the fire chamber (see Why do we light the stove at the top?)
A sufuria can be placed on the flame as soon as the stove is lit. There should be minimal amounts of smoke (see Why doesn’t the stove smoke?). Cooking time is approximately 45 minutes (using blue gum eucalyptus) at a high temperature (see How do I adjust the stove?). Cooking time may be extended by adding small amounts of wood, making sure they are below the secondary air holes (4”below the top of the fire chamber).
Gasification can be thought of as drawing smoke through the hot bed of char where chemical reactions take place. In that oxygen starved location, one oxygen atom is removed from both the CO2 (carbon dioxide) and the H2O reducing them to CO (carbon monoxide) and H2( hydrogen). When the gasses reach the secondary air holes (the circle of holes 4”from the top of the fire chamber), these gases are burned, having left an oxygen deprived zone and entering the oxygen rich secondary air combustion zone. When first placing a sufuria on top of the Malaika stove, extending the flames above the top of the fire chamber, hitting the bottom of the cold sufuria, the flames can be snuffed out (not having enough heat to combust). In this case, smoke and soot may be produced. As the sufuria heats up, more heat is retained by the bottom of the pan and there will be less smoke and soot. The reason for the flames to go above the fire chamber is that not enough oxygen is being supplied to burn all the available gases. The flames are searching for oxygen and therefore reach about the top of the fire chamber.
When the flame changes from orange, yellow and blue and turns to a deep blue, the bio mass has been turned into charcoal (see How does the stove produce charcoal while I cook?). By lifting the Malaika jiko from the traditional improved jiko, the lit charcoal falls neatly into the traditional jiko and continues to burn as charcoal. At this point, cooking or warming can continue or the charcoal can be preserved by being placed in water or in a snuff box. Another alternative is to use the charcoal as a bio char (see What is bio char?) to augment the soil.
The desire is to create a hot bed of char that is heating the wood below. This causes the wood below to release the producer gas in the wood. The process in which the gas is created is called pyrolysis. The reason why it is important to have hot coals across the top area is so that the smoke and gases pass through the hot char.
Adjustment of the stove takes practice and an understanding of how and why the stove works. The door on the improved Kenya jiko provides the air that comes up through the biomass in the fire chamber and out the top of the stove. This is referred to as the “primary air”. The primary air provides enough air for limited combustion of the bio mass/wood. The door on the Malaika jiko is for entrance of the air between the outside shell and the fire chamber. It flows in the Malaika jiko door and out the holes that are 4”below the top of the fire chamber. This is referred to as “secondary air” and provides oxygen (along with the heat from the burning char) to burn the gases that are released. By reducing the amount of primary air entering the stove, less gas will be produced giving the secondary air supply a chance to fully combust the gases. It is recommended to adjust the primary air (traditional jiko door) and not the secondary air ( Malaika jiko door). As experience increases, the stove can be regulated, keeping a balance between the oxygen, heat and fuel for desired effect.
Initially, the hot char is drying the wood. It is advantageous to have pieces below slightly larger (thicker) than the ones above. Combustion occurs after the wood gases pass through the hot char and enter the secondary air zone where they are introduced to enough oxygen to combust. The process continues uninterrupted to the bottom of the stove (burning top to bottom). The descending pyrolytic front leaves, in its wake, charcoal.
Bio char is a name for charcoal when it is used as a soil amendment. Added to the soil, it sequesters carbon. Instead of carbon being released into the atmosphere (as it is in the process of burning), the carbon is stored in the charcoal. The benefits are improved water retention, reduction of nutrient leaching, reduction of soil acidity and the reduction of irrigation and fertilizer requirements.
• Immediate cook time
• Heat (energy) during production of charcoal is used for cooking
• Carbon monoxide, hydrogen and small amounts of methane produced are all burned
• Designed to produce the right amount of charcoal to fill the traditional improved jiko
• Less destruction of wood growth than current methods of charcoal production
• Reduced smoke
• Cost savings (1 sack of charcoal in Ksh= cost of one Malaika jiko)
• Heightened awareness of conservation efforts in the areas of forestation, indoor air pollution, water resources and erosion.
• Cost savings for fuel (biomass vs. charcoal, kerosene or propane)