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Rocket Stove

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Last edited: 17 March 2024      
Rocket Stove details

The Rocket Stove, a popular variety of improved combustion stoves, is an integral part of the Integrated Cooking Method. It is easy to construct, with low-cost materials. These are low-mass stoves designed to burn small pieces of wood very efficiently. Cooking is done on top of a short insulated chimney. A skirt around the pot will help hold heat in, increasing the efficiency.

Rocket Stoves use branches, twigs, small wood scraps, or just about any small combustible material. The pieces of wood or other material burn at their tips, increasing combustion efficiency, creating a very hot fire, and eliminating smoke. The low-mass stove body and insulated chimney ensure that the heat goes into the cooking pot, not into the stove. Rocket stoves used in conjunction with hayboxes can save enormous amounts of fuel, cooking complete meals while using very few resources.

A related design, the Rocket Bread Oven, is constructed using two 55 gallon drums, one inside the other. The outer drum is split open to create an insulated chimney space between the two drums and to allow for a doorway. Baking is done inside the inner drum--in a sealed compartment within the chimney, above the firebox.

Rocket Stoves operates roughly twice as efficiently, and substantially more cleanly, than the open fire cooking methods still used in many areas of the world. 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.

Key features[]

Rocket stove made from barrel in Bolivia

A Rocket stove made from a barrel in Bolivia

The Rocket stove's main components are as follows:

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

Problems[]

Overview: Fire based solutions, such as the Rocket Stove, allow cooks to make meals when the sun isn't shining or achieve temperatures that would be difficult without expensive parabolic cookers. However, they do have drawbacks:

  • Pollution: When biomass, such as wood, is consumed completely in the burning process, it produces carbon dioxide (C02) and water vapor (H20) alone. However, according to Joel S. Levine of the Atmospheric Sciences Competency NASA Langley Research Center in Hampton, Virginia, '[s]ince complete combustion is not achieved under any conditions of biomass burning, other carbon species, including carbon monoxide (CO), methane (CH4) nonmethane hydrocarbons (NMHCs), and particulate carbon, result through the incomplete combustion of biomass material. In addition, nitrogen and sulfur species are produced from the combustion of nitrogen and sulfur in the biomass material.' Further, it is possibly the most injurious common form of generating heat in terms of particulate emissions and other pollutants.
  • Efficiency: The book, "Capturing Heat II" by the Aprovecho Research Center suggests that without a skirt the Rocket Stove is only about as efficient as a well-run open fire. With the addition of a skirt that efficiency rises, but is still less than the 40% that is sometimes cited.
  • Maintainability: Tin can stoves may disintegrated due to rust after 3 to 6 months and the constant heating and cooling of other materials can cause these to break down.

Results of EPA lab tests (2012)[]

Fuel efficient stove tests (2024)

Key findings compared with the 3-stone fire:

  • Most stoves that were tested had better thermal efficiency, but some did not.
  • Compared with the 3-stone fire, many stoves that were tested had better combustion efficiency, but many did not.
  • A natural-draft TLUD stove (ARC) had very high efficiency with processed, wood-pellet fuel with low-moisture content.
  • Some forced-draft (fan) stoves had very low emissions – but not all fan stoves did.
  • Most natural-draft stoves that were tested showed a bigger improvement (lower emissions) over the 3-stone fire with high moisture fuel than with low-moisture fuel.
  • A natural-draft TLUD stove (ARC) had very low emissions – but required processed, wood pellet fuel with low-moisture content.
  • Two rocket stoves were tested at a “medium power” level – and had lower emissions (per energy delivered to cooking pot) than at maximum power.
  • Charcoal stoves had high emissions of CO and high emissions of PM during start-up.

Alternatives/Variations[]

Sierra Zip Stove[]

An interesting alternative -- at least in the developed world -- is the Sierra Zip stove. By pumping heated air into the combustion chamber quick high temperatures can be achieved with little energy wasted on thermal mass or warm-up time. Ensconced in a cooking system which skirts the cooking vessel, 4 oz of wood will give 2-3 minutes of gas-like cooking.

Two-Door Rocket Stove[]

The Two-Door Rocket Stove can burn both wood and charcoal. It saves a lot of both! Wood fuels are fed into the big door. The small lower door controls the flow of air into the fire which lowers emissions. When burning charcoal, the big door is closed, and the rate of burn is also controlled by opening and closing the lower door.

Adding adjustable doors to a Rocket stove allows for control of the air that enters the fire to speed up or slow down the rate of combustion. More air is needed to start a cold fire and to create a hot fire initially. Once the fire is going, the bottom door is partially closed. Limiting the air increases heat transfer to the pot and reduces harmful emissions.

The popular EcoZoom Versa Two-Door Rocket stove efficiently uses charcoal to cook food.

Stovetec1

Carbon monoxide is reduced when it is burned up in the enclosed space above the fire. Frequently, enough charcoal is made when burning wood so that simmering can be done using only the made charcoal. After boiling food, the big door is closed and air from the lower door keeps the made charcoal burning. The interior grate and dual doors make the EcoZoom Versa Two-Door Rocket stove slightly more expensive than the one door EcoZoom Dura stove.

Dimensions: Stove D-11 in H-11 in (Dimensions above are as packed for shipment) Upper Door: W-4 3/4 in H-2 3/8 in Lower Door: W-2 3/8 in H-1 1/8 in

Rocket stoves are commercially available in some developed countries, and often cross subsidise projects in developing countries.

Features of EcoZoom Versa rocket cookstove:

  • Insulating, abrasion-resistant combustion chamber
  • Grate to hold both wood and charcoal
  • Two doors with sliding covers
  • Cast iron stove top
  • Stick support
  • Adjustable galvanized steel pot skirt
  • Painted sheet metal body
  • Wooden and painted steel handle

Click here for the EcoZoom homepage.

Audio and video[]

The_"4_Block"_Rocket_Stove!_-_DIY_Rocket_Stove_-_(Concrete_Cinder_Block_Rocket_Stove)_-_Simple_DIY

The "4 Block" Rocket Stove! - DIY Rocket Stove - (Concrete Cinder Block Rocket Stove) - Simple DIY

How to make a "FOUR BLOCK" Rocket Stove! Easy DIY. Four concrete blocks is all it takes to make it!. Cost $5.16. video shows you how to put it together. the stove funnels all its heat up under the bottom of the pan. uses very little fuel. fueled by small sticks, twigs and leaves. cooks great. wind and rain resistant

Rocket_Stove_Ideas_33_-_Brick_Box_Rocket_Stove

Rocket Stove Ideas 33 - Brick Box Rocket Stove

Pekka Leskela explains how his brick Rocket style stove works and is assembled.

Clean_Cooking_Stoves_for_Vietnamese_farmers_-_November_2012

Clean Cooking Stoves for Vietnamese farmers - November 2012

Vietnam Solar Serve has designed their version of a double-wall stove that allows for a secondary burn, which allows for more complete combustion and creates more heat.

Build_A_Rocket_Stove,_Step-By-Step
How_to_Make_a_Tin_Can_Rocket_Stove How to Make a Tin Can Rocket Stove
How_to_Make_a_16_Brick_Rocket_Stove How to make a 16 brick rocket stove
Rocket_stove_en_vermex_(vermiculite_expansee) How to make a rocket stove from vermiculite

Articles in the media[]

See also[]

External links[]

Capturing Heat - Aprovecho

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