List of Acronyms 

ARI                                                            –     Acute Respiratory Infection

ARECOP                                                 –     Asia Regional Cookstove Program

BCSIR                                                       –     Bangladesh Council for Scientific and Industrial Research

BRDB                                                       –     Bangladesh Rural Development Board

BRAC                                                       –     Bangladesh Rural Advancement Committee

CEA                                                           –     Country Environmental Analysis

CCT                                                           –     Control Cooking Test   

COPD                                                       –     Chronic Obstructive Pulmonary Disease

DPHE                                                        –     Department of Public Health Engineering

GDP                                                          –     Gross Domestic Product             

GHG                                                          –     Greenhouse Gas

GOB                                                          –     Government of Bangladesh

GTZ                                                           –     German Technical Assistance

HEDON                                                   –     Household Energy Network

ICS                                                             –     Improved Cooking Stove

IAP                                                            –     Indoor Air Pollution

IAQ                                                            –     Indoor Air Quality

ICDDR,B                                                 –     International Center for Diarrheal Diseases Research, Bangladesh

IFRD                                                         –     Institute of Fuel Research & Development

KPT                                                           –     Kitchen Performance Test

LGED                                                        –     Local Government Engineering Department

M&E                                                         –     Monitoring and Evaluation

MDG                                                         –     Millennium Development Goal

M.S. Sheet                                            –     Mild Steel Sheet

NGO                                                         –     Non-Governmental Organization

PRA                                                          –     Participatory Rural Appraisal

PCIA                                                         –     Partnership for Clean Indoor Air

PPM                                                         –     Parts Per Million

REIN                                                         –     Renewable Energy Information Network

IDCOL                                                      –     Infrastructure Development Company Limited

VDP                                                           –     Village Defense Party

VERC                                                        –     Village Education Resource Center

WB                                                            –     The World Bank

WHO                                                        –     World Health Organization

WSG                                                         –     Woodburing Stove Group

LIST OF CONTENTS

Prologue

Under the World Bank project ‘Bangladesh: Addressing Indoor Air Pollution (IAP)’, an attempt has been made to develop a technical manual of Improved Cooking Stove technology to be used in a pilot project ‘Mitigation of IAP in the rural area of Bangladesh’ and for those who are interested. Seven models of ICSs have been selected for delineation in this technical manual. Participants from a number of organizations working on propagation of ICSs in Bangladesh brainstormed and selected the ICS models for discussion in the manual.

This manual briefly and precisely describes the kitchen systems, general designs and construction principles of the seven suitable ICS models with detailed drawings, pictures of components, raw materials required and step by step construction procedures.

The selected improved stoves suitable for domestic cooking to semi-industrial purposes were developed by Dr. A. M. Hasan Rashid Khan, Ex Director, BCSIR, a pioneer in the field  and his colleagues at the Institute of Fuel Research and Development (IFRD), Bangladesh Council of Scientific and Industrial Research (BCSIR), Dhaka, Bangladesh. Dr. Hasan is currently working as the Project Manager of VERC-World Bank IAP Project.  All the models discussed were developed through consulting users and basing on their opinions.

The dissemination of the ICS technology has been mainly progressing in the country through conducting training courses in construction, maintenance, repair and installation of improved stoves in the user’s kitchen. Over a hundred large, medium and small NGOs and some donor agencies are engaged in dissemination of the ICS technology in the country. But due to lack of people’s participation, proper coordination, leadership and suitable funding mechanisms, the quality control and actual quantities of ICSs disseminated in the country to date have not been possible to ascertain at this stage.

While constructing different models of ICSs, technicians/ICS experts are expected to keenly consider the procedures described in details in the manual. After completion of the construction of a particular stove, its dimensions should be checked with those of the corresponding model as mentioned in the manual. The manual also describes how to use, repair, maintain and manage troubleshooting of ICS models. Additionally, popular ICS models from South Asia, Latin America and Africa are also described herein with a view to familiarizing the Bangladeshi promoters and users of ICS technology with those of other countries across the world.

To say the least, this manual should be quite beneficial and useful for all the people involved in designing, making and dissemination of the ICS technology at all levels and especially for the users at the grass-roots level.

I take this opportunity to proffer thanks to Priti Kumar, Senior Environmental Specialist, Dr. M. Khaliquzzaman, Consultant and Jonathan Rouse, Consultant of the World Bank for supporting this initiative meaningfully. Thanks are specially due to Dr. A. M. Hasan Rashid Khan, the Project Manager, VERC-World Bank IAP Project and his team members for producing this technical manual. I appreciate the constant guidance and supervision provided by Mr Yakub Hossain, Deputy Executive Director, VERC in making the implementation of this crucial undertaking possible.

Shaikh Abdul Halim                                                                                                                                     13 May 2008

Executive Director                                                                                                                                       Savar, Dhaka

VERC.

1. Introduction

More than one-third of the world’s population living predominantly in the rural areas of developing countries use wood as a primary source of energy. It is the oldest type of fuel which man used for centuries to cook food, light and heat his home, manufacture metallic objects and generate mechanical power.

In Bangladesh, about 90% families use traditional fuels viz, fuel wood, charcoal, twigs and leaves, agricultural residues, viz. plant residues, paddy husk and bran, bagasse, jute sticks and dried animal dung for cooking and other heating purposes. The total annual consumption of these fuels stands at about 40 million tonnes [study1] which constitutes about 67.97% of the total energy consumption of the country. The remaining 32.03% energy is supplied from sources which may be described as commercial fuels, such as, gas, oil, electricity, LPG, coal etc. Of the traditional fuels, agricultural residues, tree branches, dry leaves, cow dung etc contribute to the tune of 33.71% of the total national figure, while woody fuels contribute about 34.26%.

In Bangladesh, a meagre 9% of the total land area is covered by Government managed forest and this is alarmingly decreasing because of the population growth and the mushrooming not too well planned industries. All these anthropogenic factors and some natural degeneration processes lead to fast depletion of forest resources, which,  consequently effect adverse changes in the ecosystem leading to the erosion of the long prevalent climate regimes, eventually bringing about drastic changes in the climatic patterns of the country.

Only till some two or three decades back, farmers in this country used to leave a sizeable portion of the crop plants in the field after harvesting different agricultural crops. Those residues used to be left in the in the fields, which along with the cow dung generated there from the grazing cattle would decompose and mix naturally with the topsoil providing valuable organic manure to the farmland, readying it for tilling and farming throuth the ensuing season. But what’s happening today is, the farmers do not leave any crop residues in the fields any more, they are used to cutting the ripened crop plants totally, without caring for fertilizing the soils naturally and traditionally, as both the agricultural residues and cow dung are used as cooking fuels in the rural areas and many are engaged in their trades. As a result, the agricultural lands are deprived of the essential natural fertilization  in the process and therefore, solely depend on artificial, that is, chemical fertilizers for boosting production of crops. Thus the constitutions of the soils have been gradually changing, affecting the soils adversely to a considerable extent.

The common devices used for cooking and other heating purposes in the country are the three stone stoves, popularly known as traditional stoves. But efficiency of these stoves are low (5-15%) compared with the volumes of fuels they use up, that is. As a result, huge amounts of traditional fuels are being consumed every year. Apart from low efficiency, such stoves also emit smoke which contain several poisonous elements viz. in particular, carbon monoxide, formaldehyde etc. which, due to incomplete combustion of fuels  cause indoor air pollution (IAP) in the kitchen environment.  In some studies [2-4], indoor air pollution levels of particulates in rural houses using biomass fueled cook stoves have been found to be as high as 10,000 µg/m³, which is 50 times higher than the world health organization recommended permissible level of exposure Women and children are thus continuously exposed to high levels of harmful smoke which lead to serious health hazards. A number of scientific studies have reported higher incidences of chronic obstructive pulmonary diseases (COPD) and acute respiratory infection (ARI), low birth weight babies and cataract among women and children who are exposed to IAP of traditional fuels.

In the Institute of Fuel Research and Development (IFRD), BCSIR, a number of improved stoves have been developed to meet requirements in respect of biomass fuel types, shape of cooking utensils and cooking habits. The improvement was made by proper dimensioning of combustion chambers with a view to effecting maximum heat transfer to the utensils. All the models were developed through consulting users and basing on their opinions. After a particular model of ICS was developed in the laboratory, it was immediately installed in the user’s kitchen. After a stipulated period considered adequate  for obtaining significant feedback, user’s opinions about the efficacy and efficiency of the particular model of stove were obtained, applied for modifying the existing model as necessary or, if necessary, newer models were developed subsequently [study 5].

The above mentioned models may be grouped into three categories:

I.        Improved cooking stove with out chimney for domestic cooking purposes.

II.      Improved cooking stove with chimney for both domestic, large scale cooking and semi industrial purposes.

III.    Improved cooking stove with waste heat utilization.

The ICS models have been found to be saving up to 50-60% fuels as compared with the traditional ones; they save cooking time too [6&7]. ICS with chimney have been found to be reducing IAP in the kitchen environment considerably.

If one learns the techniques of making ICS,  he/she can build the stove without spending any money.

This manual describes seven specific ICS models with detailed drawings, components, materials used and the construction procedures. The manual will be quite useful for the people involved in dissemination of ICS at different levels, supervisors, technicians, extension workers and of course, the users at the grass root level.

2. The Kitchen System

2.1 Traditional Stoves

Traditional stoves in Bangladesh are usually a mud-built cylinder with three raised upper ends on which cooking utensils rest. One of the three spaces in between these raised points is used as fuel gases feed hole and the other two for flue gases exits. These stoves may be built underground or over ground. In some cases, two stoves are joined together laterally using a single fuel feeding hole. These stoves cause unnecessary loss of heat for the following reasons:

a)      These stoves are too deep, their depths ranging from 12 inches to 18 inches. Because of the large distance between the pot and fuel bed, heat transfer to the cooking pot is considerably reduced resulting in low efficiency.

b)      Because of large size of the flue gases exits between the cooking pots and the stove, much of the flue gases get out of the stove without coming in contact with the cooking pot and thus lower convective heat transfer.

c)      Since air cannot reach the bottom of the stove, considerable amount of cooking fuel accumulate at the bottom as charcoal. The efficiencies of these stoves vary from 5-15% depending on the depth of the stove and size of the flue gases exits.

Fig. No.-1 : Traditional stove commonly used in the country.

2.2  Traditional Fuels:

Different types of fuels, which are generally used in the traditional stoves are: fuel wood, twigs, leaves, straw, rice husk, cow dung in the form of dry cakes, jute stick, bagasse and agricultural residues.

2.3 Utensils:

There are two types of cooking utensils used viz. flat bottomed and round bottomed ones. Round bottom utensils are more efficient than flat bottom utensils because a greater part of the utensil’s bottom remains in direct contact with the flame. As a result, more of the content is heated at a time. Round bottom utensils are popularly used for domestic cooking. But in hostels, hotels, camps, where large amounts of food stuffs have to be  cooked, the flat bottom utensils are commonly used. In the villages, the poorer section of people generally used utensils made of burnt clay.

2.4 Cooking Process:

The majority of the people of Bangladesh eat rice, fish, pulse (dal), potato, vegetables, meat, chicken etc. All these food stuffs are cooked in water by boiling. Apart from these foods, wheat is also taken as a food by making chapati, paratha, luchi etc using wheat flour. During the winter season, most of the women in villages cook their food outside their houses i.e in the open place in their yard using straw, leaves and agricultural residues as fuels which are abundantly available at the time. They make the stove by simply digging a hole in the ground. While cooking, women generally sit in front of the stove on a block of wood called “pirhi”, holding a staff in their hand, which is used for pushing the leaves, straw etc. into the stove. During the rest of the year, they cook their food inside the house. The rich people always cook their food in a kitchen and they mainly use fuel wood, bamboo, cow dung dry cake, rice husk etc. as fuel.

3. Improved Cooking Stoves (ICS)

3.1 What is ICS?

ICSs are those traditional stoves which upon some modification/alternation/addition yield higher efficiencies when compared with the unmodified ones.

v      Salient Features of an ICS :

a)      An ICS is an improved version of the traditional stove having higher fuel efficiency compared with the traditional ones.

b)      An ICS has a grate in the middle of its combustion chamber and fuel burns on it.

c)      There is entry of primary air in an ICS below the grate which helps burning of charcoal formed during burning of fuel wood.

d)      The three raised ends of a chimneyless ICS are much smaller than those of the traditional stoves.

e)      In case of multiple mouth ICSs with chimneys, cooking in the first mouth is done by direct flame produced from fuel, while cooking in the other mouths are done by hot flue gases coming out from the first mouth and the spent flue gases are led out of the kitchen through a chimney

3.2 Benefits of ICSs:

1.              Reduce indoor air pollution (IAP) and thereby check health hazards of the users.

2.             Save 50-60% of the traditional fuels used.

3.             Reduce CO₂ emission in the atmosphere and thereby reduce the green house effects.

4.            Maintain proper nutritive values of the cooked food.

5.             Cause less blacking of utensils.

6.            Reduce cooking time as compared with the traditional ones.

7.             Cause less fire hazards.

8.            Help conserve the forest resources of the country.

3.3  Scope for use of ICSs:

·         An ICS is suitable for both domestic cooking and large scale cooking in hostels, hotels, hospital, army camp, orphanages etc.

·         An ICS can be easily designed to suit the needs of any type of semi industrial setup where fuel wood/other traditional fuels are used for heating purposes.

3.4  Raw Materials for Construction of ICS:

The main raw materials for making an ICS are as follows:

I. Mud/clay (Adhesive):   

Fine potter’s clay is most suitable for construction of ICSs. With too much clay used, the stove body shrinks unevenly and develops cracks as it dries. In such cases, it is necessary to add small portions of sand. Clay binds the sand grains tightly together and sand also prevents the clay from shrinking during drying.  Organic matter viz leaves, twigs, other sandy things create problems. Therefore, it is better to collect subsoil from a pit which may be dug down to 12-18 inches beneath the surface. First by removing the top soil, required amount of clay has to be collected, required amount of water added to the clay, cow dung/rice husk mixed with the clay lump and thus a paste prepared, which should be pliable enough to be easily spread with a shovel, and at the same time, hard enough to stay erect and not slither limply.

2)  Pieces of pottery / “U” shaped iron rods:

·            Pieces of pottery are necessary for making the hedge in the ICS, which will hold the grate.

·            Six inches long iron rods bent into a “U” shaped implement.  3-4 of these “U” shaped iron rods are embedded into the inner wall of the stove for holding the grate.

3) Pieces of Bamboo:

Some pieces of bamboo, 6-8 inches long and of 1inch width are necessary for making hedges in the different parts in an ICS.  Iron rods also can be used instead of bamboo pieces.

3.5 Tools/Equipment required for construction of ICSs:

During construction of an ICS, the following tools and equipment are required and should therefore be kept at hand:

1.        Dice/ Mold                                                         

2.       Scale/Measuring tape                            

3.       Spade

4.      Knife                                                                       

5.       Mason’s tools etc         

Dice/ Mold:

This is necessary for construction of an ICS body for domestic purposes. It is round shaped having 9 inches diameter and 18 inches height. Both top and bottom portions of it are open. The dice has two rings at the top. Banana trees can also be alternatively used for making such dices.

3.6    Different parts of an ICS :

An ICS consists of different parts, which are as follows:

1.        Structure

2.       Grate

3.       Chimney

4.      Cap

1. Structure:

The construction procedures of structures of different models of ICS are given in details in the section “Design construction procedure of different models of ICS” page No 15 of this manual.

2. Grate:

The traditional fuels commonly burn on the grate. But the main reasons for using the grate are as follows:

·   It maintains the optimum distance required for rightly training the flame to heat the bottom of the utensil.

·   It allows primary air through its hole at the bottom to facilitate burning the charcoal formed because of burning of fuel.

·   The ash generated fall down through holes of the grate.

The grate is circular in shape. It is generally made from cast iron and iron rod. The diameter of the grate is one inch less than the diameter of the mouth of the ICS.

Fig.No.3  Grate used in ICS.

3.  Chimney:

The chimney provides necessary draught to draw the air into the combustion chamber and to overcome the various flow resistances in the stove and finally lead out the spent flue gases out of the kitchen.

The chimney should be taken out through the roof, up to at least 2-3 feet above the roof which is very essential in case of thatched roofed cookhouses. So the height of the chimney is variable, depending on the height of the kitchen roof.

Proper insulation should be ensured between the chimney and the roof, specially when it is thatched. This can be done by placing another cylindrical piece of tin or clay of larger diameter around the chimney and by filling the gap between the two with clay and other insulating materials.

Bends in chimney should be avoided because it creates a pressure loss and some time flame and hot flue gases come out through the feed hole. However, in unavoidable conditions, a bend may be given but it should be made as smooth as possible.

In case of a thatched roof cooking corner, it is wise to fixed the chimney outside the kitchen by making a hole in the wall. Make a chimney holder on a platform outside the kitchen and then instal the chimney on it. The chimney can be supported by posting a bamboo pole next to the chimney, as convenient.

There are three types of chimneys, which can be used in an ICS. They are as follows:

1.        Chimney made of mud

2.       Chimney made by potters

3.       Chimney made of cement, sand and iron ring.

1.        Chimney made of mud:

A bamboo staff measuring 5-6 ft in height and 3 inches diameter has to be posted next to the chimney holder of ICS. Now, rinse an M. S. sheet pipe/bamboo staff of 3.5 inches diameter and 3 ft height with water and place it in the chimney holder. Next, pack mud around the smaller piece of M. S. sheet pipe/bamboo staff and make a mud chimney of about one feet height. Now, mould the chimney wall uniformly around the pipe and after a while, the pipe will have to be removed by slightly twisting it loose out of the mud chimney.

Wait till a day has passed and the next day should see you placing the M. S. pipe on the top of the mud chimney and making another one feet chimney in the same manner as done on the previous day. In this manner, within a time span of 5-6 days, a mud chimney of the desired, that is, required height can be made.

2. Chimney made by potters:

Chimneys may be made by potters too. In this case, a chimney will consist of 2-3 parts. When in use, one part of the chimney has to be connected with another part and supported by a fixing bamboo pole posted next to the chimney.

3. Chimney made of cement, sand and iron ring:

For longer durability, chimneys may also be made using cement, sand and iron rings. There are some   entrepreneurs across the country who have developed designs of chimneys which can be manufactured using different components of sanitary latrine. In some areas, where ICS technology is under implementation, the local entrepreneurs are also producing chimneys made of cement and components of sanitary latrine.  

4. Cap:

A cap is provided at the top of the chimney to stop rainwater entering it. It may be made with a metal sheet and the cap has three metal strips to fix it on the top of the chimney. The cap has to be fixed on to the top of the chimney in such a way that there should be enough space between the cap and the chimney top so that the smoke doesn’t get trapped within the chimney and can easily exit.

5. The Lid for Ash outlets:

Fig.No.4  Lid used for ICS:

The ash outlet lid can be a square mud plate of one inch thickness. On this plate, 5-6 holes of one inch diameter have to be made which should be slightly bigger than the hole of the ash outlet. A holder has to attached at the top of the plate. When food being cooked in an ICS reaches boiling point, the ash outlet/outlets are covered with this perforated lid. This will control the entry of primary air in the combustion chamber of the stove and the fuel will be burnt for a longer period, as necessary. This lid can be also made using M. S. sheet.

3.7  Efficiency and Fuel Saving Measurements

Ł       Efficiency Measurements:

The efficiency of the stove is defined as the ratio of the nett amount of heat absorbed by the water in the utensil and the amount of sensible heat supplied by the fuel [11].

The efficiency of a cooking stove is generally determined by the water evaporation method. It is measured  by heating a certain amount of water in a utensil using specific amount of fuel wood. The standard equation followed for this purpose is as follows:

Example:  Efficiency calculation of Improved Double Mouth Cooking Stove with Chimney (on the floor)

·         Take 3 kg of water in each of two identical utensils and place them on the stove.

·         Next, burn 1.5kg of fuel wood in the stove and evaporate some water from the utensils.

·         After the experiment in over, put the necessary data in the equation and then calculate the efficiency of the stove.

Ł       Fuel Saving Measurement (CCT):

It provides the user with an excellent visual appreciation of an ICS as compared with a traditional stove.

Example: Cooking Test in Improved Double Mouth Cooking Stove with Chimney (on the floor).

·         Four samples of rice, each containing 704 gms of rice and 3 kgs of water are to be put into four identical utensils.

·         Now, rice has cooked in two utensils on a traditional stove, one after another.

·         The other two samples of rice will have to be cooked in two other utensils on the improved double mouth stove at a time.

·         Measure the amount fuel consumed and time required for cooking rice in traditional and improved stoves.

·         Now calculate the fuel and time saved while cooking on the improved stove and compare with the same results recorded while cooking using the traditional stove and the benefits of using the ICS will be strikingly clear.

3.8. Rationale for Selection of ICS Models:

The entire cooking system viz traditional stoves, fuels, utensils and the cooking processes including cooking habits of the women folk of the country have been discussed in section no. 2.0 of this manual.  

To identify the most acceptable ICS models which are now being used in the community, a sharing meeting was held on February 20, 2008 at VERC Office, Savar, Dhaka.

About 25 participants from different organizations viz. BCSIR, LGED, ICDDR B, GTZ, Grameen Shakti, Practical Action Bangladesh, Shwanirvar Bangladesh, BRAC, Concern World Wide, Winrock International, VERC, Private Entrepreneurs etc. attended the sharing meeting.

All participants explained their experiences in dissemination of the ICS technology in the country. After brain storming discussion the following models of ICSs have been selected for the technical manual largely based on consumer preference as perceived by the participants [13]

 Table No. 1:  Selection of ICS Models for Technical Manual