Improved Cook Stove

May 27, 2009

Source: Center for Rural Technology, Nepal

improved cook stove

improved cook stove

A cook stove is a device located in specific location where fuel is burnt for cooking purposes. The located space is known as kitchen. In Nepal, biomass energy: fuel wood, agro-residue and animal dung is used for cooking purpose. Use of traditional stoves such as “agenu” and “chulo” due to its low efficiency consumes more fuel increasing the burden on women. In Nepal women are mainly responsible for cooking and collection of biomass. Besides, use of biomass energy and low-grade biomass fuels leads to excessive levels of indoor air pollution. Women and children in particular are exposed to the smoke emission. This is one of the reasons for higher rates of infant mortality and morbidity. Release of incomplete carbon products in the atmosphere due to poor combustion of biomass fuels results in green house gas effect. More than 80% of the energy need of Nepal is met by fuel wood thus exerting immense pressure on the forest resources of the country.

What is a Traditional Cooking Stove?

Many rural households use traditional cooking stoves (often only a hole in the ground) that use firewood, agro residues and cow dung as fuel. These stoves have certain inherent defects: •

  • They are less than 10 percent efficient (in using the energy store in wood).
  • The produced smoke stays in the kitchen due to absence of vent pipe and ill ventilation, which is harmful to the health of users and their families.
  • Utensils and clothes are blackened by soot.
  • The open fire results in risk of accidents with children burn and/or household fire.
  • The stove needs regular blowing.

A modified version of the traditional cooking stove is the Improved Cook Stove (ICS). Certain features have been modified to make them more efficient with respect to fuel wood consumption, make them convenient for cooking and much safer from a health point of view.

Functions/Applications

The improvements of ICS compared to the traditional stove are:

  • The closed stove results in a higher efficiency (15 -25%) of energy conversion and more safety •
  • A chimney leads the smoke out of the kitchen resulting into smokeless kitchen environment and health improvement.
  • The two pot-hole stove allows cooking with two pots leading to saving of cooking time and fuel.
  • An ICS can even be used for space heating by adding a cast iron/mild steel plate fixed tightly over the pot-holes of the stoves or by using a metal chimney which radiates heat to the ambient environment.
  • ICS can be used for heating water by attaching a back boiler to the side or around the chimney pipe.

Socio-cultural Implications

The ICS being an improved version of the traditional cooking stove and being made from local materials can be adapted to socio-cultural and ethnic diversity of the rural households. This makes social acceptance and adoption easier compared to disseminating totally alien technologies.

  • Rural people have readily accepted ICS as the design hardly needs any change in cooking patterns.
  • It is convenient for the women and safer for children. It reduces both the time spent for collection and purchase of fuel wood and makes easy for cleaning pots and pans after cooking.

History of ICS Development in Nepal

The development of ICS in Nepal can be divided into three phases. The first phase started in 1950s with the introduction of “Magan Chula” which originated in India. At that time Village Development Services started promoting ICS in some areas of Nepal. The program was aimed at uplifting the living condition of the people and reducing exposure to smoke. However, the program lacked a scientific approach in terms of design, promotion and testing.

The second phase started in the early 1970s and focused on improving fuel efficiency. Technological know how about large mud stoves with a number of rings known as “Lorena Stove” came from South America. The Women’s Training Centre of Nepal was involved in training women in construction of Lorena Stove. The main objective during this period was to find a solution to the fuel wood crisis and accompanying deforestation. Dissemination of these stoves was slow because of lack of scientific and critical application. In the late 70s, Research Centre for Applied Science and Technology (RECAST) became involved in improvement of these stoves and renamed them chulo.

The third phase began in early 1980s and included Research and Development and laboratory based work. This included a detailed assessment of cooking stove performance, standardized procedure for testing and design methodologies to obtain higher performance and efficiency. The Lorena Stove was replaced by Ceramic Insert Stove and Double Wall Stove. These stoves were designed by RECAST under the contract with HMG/UNDP/FAO Community Forestry Development Project (CFDP). After some years with support from UNICEF, the Ceramic Stove and the New Nepali Chulo were also introduced thorough Agricultural Development Bank, the Small Farmers Development Project (SFDP) and the Women’s Development Division (WDD) through their Production Credit for Rural Women (PCRW) program. Thousand of these stoves were distributed. Some modification to Ceramic Tata Energy Research Institute (TERI) models were made especially in the second ring and its size. Distribution was limited and only confined to field trail. As in the first phase, socio economic issues once again occupied the centre stage of the activities. Later the Tamang Stove was introduced. It consisted of mud brick or mud stone ICS with an iron tripod which was driven into the combustion chamber to form a better foundation. Taking into account the social context of stove construction, one pothole and two pothole stoves were introduced. These stoves were built by making metal moulds with locally available materials such as the clay and agro residues. The moulds were to maintain standards dimension and the stoves were without chimney.

Realizing the benefits of ICS promotion and dissemination, the National Planning Commission set the target of disseminating 160,000 ICSs during the Seventh Five Year Plan (1985-1990). Since then, ICS has been an integral component of development activities of many NGOs and INGOs. ICS dissemination approaches have changed from top down target oriented and subsidized approaches to a more bottom up and demand driven approach increasing the level of acceptance and sustainability of the stoves.

His Majesty’s Government of Nepal initiated a National ICS program with the support from Energy Sector Assistance Program of the Danish government since 1999. The general objective of this program is to establish a sustainable framework and strategy for making available technically and socially appropriate ICS in rural communities based on local capacity building and income generation.

IMPROVED COOKSTOVE (ICS) HOUSEHOLD

General Description

Improved cook stove (ICS) can be used for the same cooking purposes as its traditional counterpart. They can be used for cooking meals, boiling water and for cooking animal feed. ICS can even be used for space heating by adding a cast iron/mild steel plate put tight over the pot-holes for the pots or by putting a metal pipe around the space/room to make the hot air pass round the room through the pipe before going out through the chimney. ICS can be used for heating water by attaching a back boiler on the side or around the chimney pipe.

Technical Features/Aspects

ICS is made of 3-part mud/earth, 2 parts straw/husk and 1 part animal dung. The whole structure is plastered smooth with the same mud mortar. ICS has two fire openings for cooking pots, one behind the other. There is no need to blow the fire. It utilizes the heat, generated by burning fuel wood, more by the deflection of the flames and heated air inside it which travel to the second opening with the help of an in-built baffle located just below the second opening, before the hot air exits out of the chimney, which is made of unburnt clay bricks that are abundant in the village. The iron plates are fitted on the potholes for pots. The potholes are round in shape, the pot bottom fits tight on them. It can be made in different sizes and capacities to suit the family size and pot size. It can have one or more openings for pots/pans.

Advantages

  • ICS can be made of local materials and installed by the villagers themselves.
  • It is cheap and easy to operate.
  • There is no need to blow the fire.
  • It can be made in different sizes and capacities to suit the family size and pot size.
  • It can have one or more openings for pots/pans.
  • There is no smoke in the kitchen.
  • Cooking pots/pans are less darkened with soot deposits.
  • Sanitation conditions inside the kitchen are much improved. There is much less risk of household fire or children burning themselves.

Durability

ICS is strong enough to withstand the pressure exerted on the pots/pans while cooking such foods as Dhindo.

Potential

Practically all-rural houses can have an ICS installed in place of the traditional cook stove. Even the poor can have an ICS installed through the trained ICS builders (Promoters).

Environmental and Efficiency Implications

  • ICS can save 30 – 35% of fuel wood compared to traditional stoves.
  • Cooking pots/pans are easier to clean, as there is less soot. Hence, the pots/pans last longer.
  • Sanitation conditions inside the kitchen and even in other in-house spaces are improved as there is no smoke.
  • Health conditions of the users and their family are improved due to the healthy kitchen environment.
  • It acts as a cooler inside the kitchen as hot air goes out of the chimney.
  • All the materials used in the ICS can be used again and again upon dismantling.

Disadvantages/Limitations

  • The ICS have to be repaired and maintained regularly by plastering/pasting broken or loosened mud/plaster around the stove to ensure that there is no gap between the pots/pans bottoms and the openings – otherwise it may lose dimensional accuracy which makes it lose its efficiency advantage.
  • The baffle inside ICS has to be repaired frequently to maintain shape and size to make ICS operate efficiently.
  • The chimney should be cleaned of soot every 2 – 3 months.
  • Poor quality of workmanship and dimensional variations during construction may not render it as efficient as it is said to be.
  • ICS have low space heating efficiency.

Types of Domestic ICS

Depending upon the family size and need, following ICS for domestic purposes can be constructed.

  • One pot hole ICS
  • Two pot hole ICS (Plain type)
  • Two pot hole ICS (Raised surface)
  • Two pot hole ICS (Standing type)
  • Three pot hole (Plane and Raised surface)

Resource Assessment

Materials

The materials used in the ICS are mostly local materials, which include:

  • Stones/Bricks
  • Mud/Earth
  • Straw/Rice Husk
  • Iron Plates/Rebars/Sheets
  • Animal Dung

The amount of materials required for an ICS with two openings is as follows:

Clay/Mud/Earth 5 tins (oil cans)
Animal Dung 1/2 tin
Rice Husk or Straw Pieces 2 tins
Unburnt Clay Bricks/Stones x 40
Chimney Blocks x 25 (8″ x 8″ x 3″ with 4″Øhole in the centre)
Iron Bars ” Ø bars 16” long x 6 pieces
Iron Metal Sheet x 1 (one side of an oil tin)

Manpower/Labor

ICS can be installed by local people after a week long hands on skill training. A trained male or female can install 2 – 3 ICS in one day provided all the materials are available at site.

Tools

Installation of an ICS requires the following tools:

Item Unit
Spade for Working In Mud 1
Cutter for Bricks/Stones 1
Trowel 1
Wooden Brick Mould 1
Wooden Mould for Chimney Blocks 1
Iron Kit for Making ICS Openings 1 Set of Two
Crowbar or Chisel 1
Hammer 1
Tape Measure 1
Water Pot/Bucket/Pitcher 1

Cost Parameters

Since ICS is constructed with all the locally available materials except for the iron rod, the users only bear the cost of iron rod and installation cost which vary depending upon the place. Hence the cost for ICS installation is around 300-400 NRs.

INSTITUTIONAL IMPROVED COOKSTOVE (IICS)

General Description

Traditional Institutional Cook stove are in use at hospitals, hostels, barracks, teashops and restaurants. Industries like wool dyeing, oil seed roasting for oil extraction and confectioners use them. These large type cookers use a lot of firewood and create negative sanitation and health conditions for the workers.

Functions/Applications

Improved Institutional Cook stove (IICS) can be used in hotels, restaurants, teashops, hostels, schools, army barrack and other places. Similar to household ICS, IICS can also be used for heating water by attaching to a back boiler or around the chimney pipe and for space heating by putting a cast iron or mild steel plate tight on the openings for pots/pans or by running a sheet metal pipe around the space to be heated.

Technical Features/Aspects

IICS can have 1-3 openings for cooking pots, one behind the other. It is made of bricks/stones in a mud and mortar mixture, 3 parts each, 2 parts rice husk/straw pieces and 1 part animal dung. The mechanism is same as in household ICS. Firewood is burnt below the first opening and the flame and hot air are directed to the second then third openings in turn by the baffles, before exiting the cook stove through the chimney (made from unburnt bricks or iron sheet metal). An iron grid supports the burning firewood and lets air into the cook stove and ash and charcoal to settle below.

Advantages

  • Villagers can install IICS after short duration training.
  • It can be constructed from local materials.
  • It saves up to 30 – 35% of firewood consumption.
  • IICS is cheap to install and is easy and convenient to use.
  • It can be made to suit the needs of the user, i.e. the size and number of cooking pots.
  • There is no need to blow air into it.
  • Pots/pans are cleaner as there is less soot.
  • The work place is cleaner and healthier without smoke.

Durability

An IICS can withstand the pressure of large pots/pans. With minor but frequent repair and maintenance such as plastering, pasting and cleaning the chimney the unit can last for years.

Potential

All traditional institutional cook stove can be turned into IICS as they are made of the local and cheap materials and it can be easily installed by masons or trained village males/females.

Environmental and Efficiency Implications

  • IICS saves up to 35 – 40% of fuel wood.
  • The work place is smoke free and neat.
  • The cleaning of pots is easier (less soot).
  • All materials used in the IICS can be used again and again.
  • Operation is convenient and easy. Disadvantages/Limitations
  • IICS needs regular but easy maintenance.
  • Poor quality of workmanship and dimensional variations during construction may not render efficiency as claimed. It may lose dimensional accuracy if not maintained frequently.

Cost Parameters

Since all the required materials are locally available except for the iron rods, the users have to bear the cost of iron rod and the installation charge of the promoter, which is approximately Rs.250-350 depending upon the place.

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One Response to “Improved Cook Stove”

  1. angie Says:

    in africa we commonly use 3 stoned stoves n not the one with the hole.
    I would love to construct one of this but I have no idea how the structure beneath the plaster looks like(the original undeveloped stove)is it made of stone? how does it look like?
    please give me a description.
    thankyou.


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