High altitude space heating and cooking stoves in Pakistan

Ghulam Umar Sarhandi, Pakistan Council of Appropriate Technology, Islamabad, Pakistan

Country Profile:

Pakistan, Iying between latitudes 24N and 37N, longitudes 61E and 75E, and having an area of 880000 square kilometres, is one of the most densely populated countries of the world with population of around 130 million. More than 68 per cent of the population live in rural areas. There is diversity in social habits, usually dictated by geographical situation, including cooking, religious beliefs, regional or ethnic practices.

At present, it is estimated that 40 per cent of the total energy used in Pakistan comes from biomass. The per capita energy consumed is very low compared with other countries of South East Asia (Thailand, Philippines, Indonesia, Malaysia etc.).

Depending upon the availability of fuelwood, people use wood, cow-dung cakes, crop stalks, bagasse, some grass bushes and even leaves as a fuel for cooking, but for space heating only fuelwood or charcoal is used. Details of fuelwood consumption can be seen in Table 1.

Heating-cum-cooking devices are widely in use in the colder regions of Azad Kashmir and the mountainous areas of Rawalpindi. They complement the way of living of the people and have, therefore, become a basic component of the household. Mostly, these devices are installed in the bed room, which also serves the purpose of kitchen during the winter. In the semi-urban regions of Swat district and Rawalpindi district, smaller, round heating stoves are used.

Stove use

Heating requirements

Heating requirements vary during the winter season, which spreads over five months. In November, heating is only for four or five hours. In December and March the house is heated all night (eight hours or so) while in January, the heating is required both night and morning. February is the month of snowfall and rains and heating is required for almost 24 hours a day.

Table 1: Share of fuel wood uses in households in Pakistan during 1991

Source HESS Energy Wing, Planning and Development Division Government of Pakistan Islamabad 1991

Adoption of multi-purpose stoves

Before 1975, there were exclusively separate cooking and heating stoves or open fires throughout Pakistan. Even now, in some areas, cooking and heating are separate, while in other colder regions, cooking-cum-space heating stoves with chimneys are in general use.

Types of fuel

The same types of wood are used for both cooking and heating stoves except for branches which are only used in cookstoves. This is because wood which burns for relatively long periods is needed for room heating. In one of our pilot areas pine, deodar and few non-cultivated trees are used for heating. Branches of fruit bearing trees are also used for cooking, but not for space heating which requires logs to keep the fire going.

Benefits of chimneys

Space heating varies from house to house depending upon individual choice. The cost of fabrication construction of stoves with chimneys is twice or sometimes three times as high as that of stoves without them. Further, fuelwood consumption in stoves with chimneys is more than that of stoves without; therefore, the running cost is also high. Those who have easy access to woodfuel are more likely to use stoves with chimneys.

Conditions for space-heating use

People in colder areas mainly use cooking-cum-space heating stoves and only a few stoves are exclusively for heating. They are used for cooking breakfast and supper only. Lunch is usually cooked on an outdoor cookstoves unless there is rain or a snowfall during the daytime, then it too is cooked in the living room.

The stove programme:

Structure of the programme

The Fuel Saving Technologies (FST) Programme was originated to consider fuelwood conservation and to help rural women by reducing smoke in the kitchen and to provide education on energy and environmental awareness. The existing programme is a broader one concentrating on both cooking and heating. During the three years from 1995 to 1997, 70,000 fuel saving devices will be produced and disseminated throughout the country. Of these, the number of cooking-cum-space-heating stoves will be around 15,000. Less attention is paid to space heating because only 15-16 per cent of the population of Pakistan lives in colder regions where space-heating is required.

Origins of the stove programme

The stove programme was set up with a modified version of an Indian stove called the 'Nada Chulah'. Before 1988 only 2500 improved cookstoves were constructed in rural and semi-urban areas of Pakistan. A need was felt for a properly organized programme.

A National Seminar on improved cookstoves was organized in Islamabad, the Federal Capital of Pakistan, with the collaboration of the RWEDP of the FAO Regional Office, Bankok. During three days of deliberations a close interaction between the Domestic Energy Saving Project (DESP) of GTZ, Germany and PCAT came into being, which led to a Pak-German project 'Fuel Efficient Cooking Technologies' (FECT).

This project, under which some 40000 metallic cookstove IMPS) were fabricated, was approved in January 1990 for a period of three years. Two improved versions, the Jargan-B3 (JB-3) and the JarganB-5 (JB-5) were developed, tried and disseminated (see Figure I). These had the following advantages:

· Performed well at low as well as at high power.
· Wood saving compared to traditional stove is 25 per cent.
· Cooking time is shorter and PHU is higher.
· Smoke is very much reduced.
· Thick metal sheet provides greater durability.
· Reduced emission of carbon monoxide and smoke provides better atmosphere in the kitchen.

Figure 1: Improved round heating-cum-cooking stove: JB-5

Stove development

The improvement in design was made by reducing the size of the fire box by means of a baffle, which limits the amount of wood fed into the stove and slows down the speed of gases escaping through the chimney.

Materials used

The improved cooking-cum-heating stoves are made with thick metal sheet (usually 22 gauge) including both stove body and grate; the material for chimney construction is left to the end users. Most people use discarded kerosene oil tins for constructing chimney, while some use metal sheet of 24 or 26 gauge. In a few cases, earthen chimneys are used.

Stove Construction method.

Only skilled metal workers can produce the improved stoves. Dies have to be designed and bending machines have to be purchased from the market. These are provided free of cost to the metal workers who are given training in fabricating the stove.

Fuel feeding and ash removal

The baffle alters the speed of the flue gases leaving the chimney and is one of the major factors affecting wood consumption. It makes the size of combustion chamber smaller so that less wood is needed. Sliding doors on the improved heating stove adjust automatically according to the fuel load and they are unaffected by the size of the wood so smoke does not escape through the door.

Operation and Maintenance of the stoves

Compared to a conventional stove, this stove is easy to operate and maintain. Stove tests found that the improved version operated at low power (see Table 2). The speed of hot gases is reduced by the baffle so that maximum heat is given out to the stove body before they leave through the chimney. A large amount of charcoal is accumulated in the combustion chamber which keeps the stove body hot thus reducing the frequency of wood feeding and the attention of the operator.

Figure 2: Chitral Stove

Due to its complex structure, cleaning of the improved stove is difficult. More regular cleaning is needed as the narrow channel for flue gases causes more soot to be deposited in the stove which may cause a blockage.

To avoid smoke leakage, tightly fitting pot hole lids have to be produced.

Further development

· The cooking hole dimensions are fixed already. The users would prefer provision for different sizes of cooking utensils to fit on the stove.

· Quality control needs to be maintained, as stove dimensions, especially pothole lids, are vital for the good working of the stove.

Stove Costs

Capital Cost

The JB-5 stove, made with 22 gauge sheet and weighing 5kg, costs less than the Kalam stove or the Chitral stove (Figure 2). it occupies less space and is therefore more popular among the poorer sections of the population. The Kalam stove is much larger, it is made from 24 gauge sheet, weighs 6kg, and is less popular. The improved version of the Chitral stove made of 22 gauge sheet and weighing 5.5kg is gaining popularity with the rural population.

Table 3: Laboratory test results of 5kg test (traditional vs improved)

*Keeping the difference in room temperature at 18°C, 5kg wood lasts longer in improved stove

**The emission of CO in the improved model is 61 % less that in the traditional stove

Running Costs

Heating-cum-cooking devices consume approximately 25 per cent less wood than traditional ones Results from comparative tests carried out in the laboratory are giver in Table 3.

Durability

It is estimated that life expectancy of these models is three years, assuming their use for 5 months in a year, depending upon the quality of material. If new 22-gauge steel sheet is used the durability of stove is ensured for a period of 3-4 years. Much depends on its cleanliness; if the stove is properly maintained and ash is removed at the proper time, the life expectancy is as stated other wise the stove may need to be discarded within two years.

Stove dissemination

Multi-pot improved clay stoves are disseminated through the trained workers of PCAT, potters and other collaborating agencies. Metal cooking-cum-heating stoves are disseminated through commercial metalworkers and blacksmiths. From the metalworker the stoves are supplied to NGOs for dissemination, or direct to the end-users. Also, a number of shopkeepers keep stoves in stock.

Subsidies

At present, people usually pay the full cost of the stoves and no subsidies are involved. In a few cases chimneys are provided free to the NGOs who are collaborating with PCAT in the implementation of this programme. In the case of multi-pot improved clay cook stoves, people provide and prepare the clay treated with sand, cow dung and wheat straw which is needed for this purpose. The stove is built by a PCAT worker or a trained worker belonging to a local NGO. The chimney is provided free by PCAT. For metal conking-cum-heating stoves, metal fabricators are provided with a free bending machine, as an incentive. They are given a margin of 10 per cent profit over the fabrication cost and this subsidy is borne by PCAT. Also, the transportation charges from the metalworker to the end user or shopkeeper is home by PCAT. Therefore people are provided with stoves at the fabrication cost.

Table 3: Cooking efficiencies of the the stoves