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The improved Cooking Stoves
[top] [end]1. The issue in briefLiterature reports that the three stones open fire (TSF) persists as the most prevalent fuel-using technology to cook the meals in the villages and urban slums of the developing world. Traditional stoves have been around for thousands of years and have evolved to meet the local needs in a way that is affordable for the users. There are many sophisticated types of traditional stoves, ranging from mud stoves to heavy brick stoves to metal ones The fuel-efficiency of traditional stoves are said to be approximately five to ten percent. Since nearly three billion people in the world use traditional stoves to cook their meals, efforts to improve the efficiency of cookstoves have been increasingly popular in the developing world. But it is a hard task to offer improved stoves at an affordable price to households even if they are more fuel efficient. Additionally, the fuelwood demand presents several environmental concerns. Locally, the shortage in fuelwood supplies has become a source of forest degradation in specific regions of the world. These regions usually combine high population densities, growth of fuelwood users, a rapidly disappearing forest resource base associated with soils erosion, and a sizeable biofuel demand from small industries. Globally, the fuelwood use results in net greenhouse gas emissions. To prevail over the TSF, the Improved Cooking Stove aims to save cooking time (increasing efficiency), as well as, to create a smokeless environment in the kitchen and/or reduce the volume of smoke emission. [top] [end]2. Trends and HistorySome very interesting cases of improved stoves technology from the 1800 and early 1900 are found in various literature resources. Their relevance is not just historical! These documents bring to new life the experience and inventiveness of people from the a recent past where energy was scarce; their solutions are indeed suitable for our present and even more for our future.
Since the 1940s, efforts have been made to increase the efficiency of biomass cookstoves by governments, international development organizations, and NGOs. But improved biomass cookstoves have not reached enough households in rural settings in developing countries where three quarters of the world's 1.2 billion extremely poor people reside. This leaves the rural poor without access to increased efficiency stoves, preventing a reduction in indoor air pollution, greater time spent collecting firewood, as well as the use of dung and crop residues. In 1947 was reported the first Improved Cooking Stove at Magan Chulha, India (Maithel, 2005). According to FAO (1993), in the early 1950's in India the first phase of Improved Cooking Stove development started with technological attempts to improve the design of biomass-fired stoves. However, the scientific research and development of the Improved Cooking Stove began to proliferate in the 1970s and early 1980s. According to Kammen (1995), the first Improved Cooking Stoves were designed by aid groups such as United Nations Children's Fund (UNICEF) and the Humanitarian Organization Fighting Global Poverty (CARE) in Kenya. Due to lack of field-testing, the designers of those first Improved Cooking Stoves, mainly natives of the U.S. and Europe, obtained weak results. Sometimes, the stove's opening did not match the size of most pots utilized by the users. Even more fundamental problems plagued some of the early prototypes. Designers acted as if it would be an elementary exercise to improve the efficiency of the common metal stove, a deceptively simple canlike enclosure into which charcoal or wood is fed and ignited. In fact, after much trial and error, it turned out that an extensive investigation of stove physics and engineering design was needed. This analysis revealed that the largest loss of heat from the fire, about 50 to 70 percent, occurs from radiation and conduction through the metal walls. Makers of some of the first stoves took measures to deliver more of the fire's energy directly to the pot (Kammen, 1995). Since the late 1970's, attention has been focused on the design and dissemination of simple, low-cost improved cookstoves. Such stoves can save up to 40% of the wood fuel compared to open fires, and 25-35% of the fuel compared to traditional stoves. The advantages of using improved cookstoves include:
Better stove designs gradually came about during the mid-1980s. At that time, a number of academics began to publish serious analyses of optimal stove combustion temperatures and of the insulating properties of the ceramic liner materials. In such way that the newest designs took into consideration the complex interaction between the different processes that take place in a cookstove, such as: combustion, heat transfer fluid flow and material science. A large number of Improved Cooking Stove models, based on different construction materials, fuel and end use applications, have been developed during the last 10-15 years. Improved cookstoves can be designed and built in various ways, depending on the local conditions. According to Foley and Moss, 1983, 'At their simplest, improved stoves rely on providing an enclosure for the fire to cut down on the loss of radiant heat and protect it against the wind. In addition, attention can be given to devising methods of controlling the upward flow of the combustion gases, so as to increase the transfer of heat to the cooking pot'. Many of these stoves are made of mud or sand since both are almost free and readily available. According to FAO (1993) the Improved Cooking Stoves can be classified into various categories:
Table 1: Types of improved cook stoves
A mud stove is usually a stable device that can have one or more pot hole. Generally a fixed improved cook stove requires adequate pre-and post installation education and training for the user on auto-building, proper use and maintenance. Local clay, straw, dung, cement and stone are the main materials used in the construction of a stable device cooking. The mud-stove can be sized to fit the family’s own pot(s). Portable stoves are characterized by one pot hole and are more widely used than fixed stoves. A multi-fuel improved stove is usually characterized by a mobile grate which allows the use of a variety of available fuel (wood, charcoal, dung, agriculture residues). A multi-cooker improved stove matches a range of user’s pot size. For more information on portable stoves please visit the portable improved stove page. [top] [end]3. Current Best PracticeThe thermo electric generator stoves can be used to - cook food, heat the room and generate electricity?. These stoves, named as UJELI stoves (meaning light in Nepali language, were developed in Engines and Energy Conversion Laboratory of Colorado State University and the project was implemented in Nepal through STARIC/N (Sustainable Technology Adaptive Research and Implementation Center/Nepal ). Ujeli Chulo is now being field tested in Gatlang Village in Nepal. This wood-burning stove consumes wood in a far less quantity than the traditional open fires.The Philips wood stove developed by Philips runs on a thermoelectric generator using the heat from the burning wood to generate electricity for the fan. The fan forces the air through the stove, leading to higher temperatures and a better fuel to air ratio. This results in cleaner burning and more efficient use of fuel. The rocket combustion chamber? is designed so as to achieve almost complete combustion of wood thus increasing the efficiency and decreasing indoor air pollution particularly the particulates and carbon monoxide. The stove also has a chimney stack that removes the exhaust outside the room thus making the room free of any smoke. The most novel feature of this stove is that it also generates electricity that powers the bright CCFL lights. 3-4 hours of cooking everyday provides light for 2-3 hours at night or daytime. Furthermore, the stove also radiates heat which warms the room (Shrestha, HEDON). A case history that traces the progress of stove development from early misstep to ultimate acceptance can be found in East Africa. Almost one million households now cook with the Kenya ceramic Jiko?. The Jiko--the word means "stove" in Swahili--consists of a metal casing with a ceramic lining that helps to direct 25 to 40 percent of the heat from a fire to a cooking pot. KENYA CERAMIC JIKO (left) increases stove efficiency by addition of a ceramic insulating liner (the brown element), which enables 25 to 40 percent of the heat to be delivered to the pot. From 20 to 40 percent of the heat is absorbed by the stove walls or else escapes to the environment. In addition, 10 to 30 percent gets lost as flue gases, such as carbon dioxide (Kammen, 1995). [top] [end]Self-built or Factory-built?Initially there was a tradition of owner-building of stoves but experienced observers are concluded that the small industry production of stoves is one of the most promising routes to take.The advantages of this approach include:
Costing $1-5 each, the stoves can often pay for themselves in fuel savings within 1-2 months if the fuel is purchased. In rural areas where most fuel is gathered, very low-cost stoves can still be sold to some people. [top] [end]4. Areas of Research
[top] [end]Effects on fuel conservationFuel conservation through improved cookstoves appears to be the cheapest way for a nation to invest in new sources of energy. The typical artisan-produced cookstove conserving 35% of fuelwood costs less than $5.Liquified Petroleum Gas, electric and kerosene stove have the added daily cost of fuel, which in the case of the improved stove is nil (because improved efficiency alone accounts for all of the gain). The secondary effects of existing cooking systems must be understood before acceptable improvements can be made. In many places, smoke from indoor cooking fires is a significant contributor to lung and eye disease. Yet this smoke also serves to dry crops hung over the cooking area and to protect thatched roofs from insect damage. In highland regions and other colder areas, the space heating function of the indoor cooking fire may need to be included in cookstove design. Successful stove promotion efforts may depend on the availability of effective alterations for these secondary functions of the cooking fire. A 35% savings in fuel is considered a realistic figure for the better stove designs. Similarly, most agree that the distribution of improved stoves alone is not going to greatly affect the rate of deforestation in most places. Nevertheless, improved cookstoves are now considered to be a cost-effective component in reforestation programmes in some countries, and clearly they have a role to play in improving the quality of life by conserving family resources of cash and time, and reducing smoke in the cooking area. Improved stoves attain high efficiency by:
This is achieved by incorporating all or some of the following components mentioned below. 
The increasing acceptance of the improved stove shows that stove programmes have positive impacts on users,
In some parts of the world, notably China, and to some extent India, significant progress has been made in the dissemination of improved cookstoves, with numbers of improved stoves in use numbering in the millions. In Africa, only Kenya claims a stove dissemination level that exceeds a million. The difficulty of disseminating improved stoves in Africa is the subject of a separate article. Cookstoves, despite being a basic energy technology, have appreciably improved life in the kitchen. Another issue that energy researchers need to consider is that of Food Security and Energy The key question is; How do we direct the development and provision of energy services to enhance food security in developing countries, particularly in Africa, where food security seems to be an issue each and every year [top] [end]5. Resources
[top] [end]6. Organizations and People[top] [end]7. Web links[top] [end]Stoves and Emission[top] [end]Environment
[top] [end]Health
[top] [end]8. Related Documents
[top] [end]Contributors
Categories: Improved Stoves | |||||||||||||||||||||||||||||||||||||
Page created:
25 August 2003; Last edited:
11 September 2008; Version: 18 | |||||||||||||||||||||||||||||||||||||
Pagename: ImprovedCookstove @HEDON: | |||||||||||||||||||||||||||||||||||||
WhatMakesPeopleCookWithImprovedBiomassStoves.pdf (3,167 KB)