Biomass cook stove

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Stove manufacture in Senegal.
Stove manufacture in Senegal.

In cooking, a cook stove is a very basic stove heated by burning wood or fossil fuels. Cook stoves are the most common way of cooking and heating food in developing countries.

Developing countries consume little energy compared to developed nations; however, over 50% of the energy that they do use goes into cooking food. The average rural family spends 20% or more of its income purchasing wood or charcoal for cooking. Living in the city provides no refuge either as the urban poor frequently spend a significant portion of their income on the purchase of wood or charcoal.

Besides the high expense another problem of cooking over an open fire is the increased health problems brought on from the smoke, particularly lung and eye ailments, but also birth defects. Replacing the traditional 3-rock cook stove with an improved one, and venting the smoke out of the house through a chimney, can dramatically improve a family’s health.

Deforestation and erosion are often the end result of harvesting wood for cooking fuel. The main goal of most improved cooking stoves is to reduce the pressure placed on local forests by reducing the amount of wood the stoves consume. Additionally, the money a family spends on wood or charcoal translates into less money being available to be spent on food, education, and medical care; so an improved cooking stove is seen as a way of boosting a family's income.

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[edit] Three stone cooking fire

The traditional method of cooking is on a three stone cooking fire. It is the cheapest stove to produce, requiring only three suitable stones of the same height on which a cooking pot can be balanced over a fire. However, this cooking method also has many problems:

  • Smoke is vented into the home, instead of outdoors, causing health problems. According to the World Health Organization, "Every year, indoor air pollution is responsible for the death of 1.6 million people - that's one death every 20 seconds."[1]
  • Fuel is wasted, as heat is allowed to escape into the open air. This requires more labor on the part of the user to gather fuel and results in faster deforestation (if wood is the fuel being used).
  • Only one cooking pot can be used at a time.
  • The use of an open fire creates a risk of burns and scalds.[2] Especially when the stove is used indoors, cramped conditions make adults and particularly children susceptible to falling or stepping into the fire and receiving burns. Additionally, accidental spills of boiling water may result in scalding, and blowing on the fire to supply oxygen may discharge burning embers and cause eye injuries.

[edit] Improved stoves and other measures

The negative impacts can be reduced by using improved cook stoves, improved fuels (e.g. biogas, or kerosene instead of dung), changes to the environment (e.g. use of a chimneys), and changes user behaviour (e.g. drying fuel wood before use, using a lid during cooking)."[1]

[edit] Kenya Ceramic Jiko

From the beginning of the Appropriate technology movement, one of the principal goals has been to create an affordable stove that was more efficient than the universally used three stone cooking fire. Of all the improved stoves, the Kenya Ceramic Jiko (KCJ) has been the most widely accepted to date, having become a standard item in most homes in Kenya and neighboring countries in East Africa.

Charcoal is the standard cooking fuel in East Africa. Traditionally it was burned in a metal stove or “Jiko” as stoves are called in the Swahili language. The KCJ is simply the traditional Jiko mated to a ceramic liner, producing a stove that is at least one fourth (and up to 50%) more efficient than traditional all-metal alternatives, costing only $2 to $5. It has a distinctive shape, differing from the traditional cylindrical jiko, with the top and bottom the same diameter, tapering at about 30 degrees to a waist.

There are many variations on the same theme that can be found in Kenya and other areas of East Africa. Some are designed to be more robust than the original KCJ, and some such as the Upisi are designed to burn wood instead of charcoal, while others some are built into the home, and remain stationary.

[edit] Sanjha Chulha

This biomass briquette cook stove designed for community kitchens. Since 1999 a small company based in North India (nishantbioenergy.org )is manufacturing these stoves. Biomass briquettes can be made from any farm or forest residues with or without binders. Advantage of the stoves are lower cost of operation, user friendly , carbon neutral and safe to operate. They have many designs ( Sanjha Chulha and Earth Stove) starting 16000 KCal/Hr to 60000 KCal/hr. There stoves are being used by variety of people cooking food for 50 people to 50,000 people per day. As on date ( May, 2008) they have installed around 140 stoves ( totaling 7 million KCal/hr capacity replacing around 4000 Kilo of LPG per day) and executing projects worth 3.5 Million Kcal/hr. They have also two franchisee in western states of India and planning three more to spread the technology.

The company won many national and international recognizations for there unique efforts like Ashden Award-2005, PCRA Award -2001, UN promising practices-2006.

[edit] Lorena adobe stove

The Lorena adobe stove was designed as a simple-to-build cook stove for use in Central America, one that could be manufactured locally of local materials. It became very popular in Central America, with anecdotal evidence suggesting that it is the most popular improved cooking stove in the region. The Lorena stove is an enclosed stove of rammed earth construction, with a chimney built onto it.

The Lorena stove was designed with the mistaken belief that rammed earth would act as insulation; there was a basic misunderstanding of the difference between mass and insulation. Good insulation resists the passage of heat; thermal mass does the opposite, it absorbs heat. Testing has shown that the rammed earth used in the Lorena stove does absorb heat, heat that should have gone into heating the cooking pot.

The designers, Aprovecho, now state: “The Lorena has been tested over the years by many researchers and has generally been found to use more firewood than an indoor open fire. The stove has other attributes. Its chimney takes smoke out of the kitchen and it is well liked. It is pretty and a nice addition to the house. It is low cost and can be repaired and even built by the home owner. But, it is not a fuel saving or low emission stove.”

[edit] Improved Lorena (Justa) stove

The Improved Lorena or Justa stove has a sealed metal cooking surface that sits above a stove made of bricks, and a chimney that carries the smoke outside.

The Improved Lorena stove is a simple biomass stove built around an insulated, elbow-shaped combustion chamber which provides more intense heat and cleaner combustion than an open fire, meaning that it consumes less fuel then a 3 rock stove, removing smoke from the house.

[edit] Standard approaches to conserving cooking fuel

Almost all rural and many urban families in Latin America rely solely on wood for their cooking needs. In most of Africa charcoal is the standard cooking fuel. In other places it can be a mix of the two, or alternatively like families on the Great Plains during the 1800’s animal dung may be in common use if it is the only thing available.

There are three places in the cooking process where fuel can be conserved; the fuel, the stove, and the cooking pot. The greatest gains come not from the stove itself, but from how the heat the stove produces is used; paying attention to the pot rather than the stove results in the greatest fuel savings. In fact, fuel efficiency in a stove is usually much more affected by heat transfer to the pot than it is by improving combustion efficiency.

  • The first way to reduce the amount of fuel a family consumes is simply to use a cooking lid while cooking, which by itself reduces fuel consumption by 40%. This simple change will normally save more fuel by itself than switching to an improved stove.
  • The second strategy is similar to the first; use a larger cooking pot. Larger pots are more energy efficient than smaller ones and wide shallow pots are more efficient than tall narrow ones.
  • Last, when cooking for a family, switching from a stove that has room for only one pot to cook at a time, to a stove where two or more pots can cook at once will often raise efficiencies by up to 40%.

In developing countries, families who rely upon wood for cooking have three ways of obtaining it. They can scavenge the areas where they live for firewood, purchase it from a firewood dealer, or grow their own. In most villages there is a lack of harvestable firewood in the surrounding area, and so most of the wood used is brought into the village and sold through a dealer. Those who cannot afford to buy firewood are often forced to travel several miles to acquire wood. Some families have obtained self-sufficiency by maintaining a living fence, or growing a woodlot near the family home.

[edit] Smokeless stoves and wood conserving stoves

Smokeless stoves and wood conserving stoves are terms used to describe stoves designed for developing country settings to reduce the health impacts of smoke from open fires inside dwellings. It is generally claimed that the new designs burn the wood (or other fuel) more efficiently. Important features may include a pipe (chimney) to vent the smoke and a different chamber design.

There are various designs. One is the Lorena stove. Another is the ONIL Stove which uses mortar-less concrete blocks in its construction and costs $125 USD per stove.[3]

[edit] See also

[edit] Notes and references

  1. ^ a b Indoor air pollution and health - World Health Organization fact sheet.
  2. ^ Health Benefits. The ONIL Stove. Retrieved on 2007-04-13.
  3. ^ The ONIL Stove. HELPS International. Retrieved on 2007-04-14. “Each stove costs only $125...”

[edit] External links