|Boiling Point No. 38 : Household Energy in High Cold Regions (ITDG - ITDG, 1997, 40 p.)|
Based on conclusions reached in the regional workshop on space heating in Pokhara, Nepal, February 1996
Energies domestiques dans zones de haute altitude:
L'auteur souligne que l'analyse des besoins de chauffage des locaux dans les rons de haute moutagnes requiert des approches spfiques. Les foyers multi-usages (cuisson et chauffage) sont encore peu rndus quoique les technologies sont disponibles. Gralement, les programmes sur les foyers n'accordent que peu de place a conception d'ipements multi-usages. Le moyen le plus simple de chauffer des locaux est d'utiliser la chemincomme radiateur. Cependant l'optimisation des deux fonctions implique davantage d'efforts en mati recherches dloppement. Quant au chauffage solaire des locaux, les couts restent extremement v Dans quelques zones montagneuses du Nl, ITDG a introduit des ipements de cuisson utilisant l'ctricitLes recherches qui ont ete men pour accroitre l'efficacite cuisson n'ont pas retenu l'attention des usagers dans la mre o pertes de chaleur servaient en fait au chauffage des locaux. Cet exemple montre que les strates de promotion des foyers sages multiples sont diffntes de celles ayant pour seul objet la diffusion de foyers utilisprincipalement pour la cuisson.
Cold altitudes and the need for space heating
A large majority of people in the developing countries live in hot climates and there is a need for coolness rather than heating in their homes. Nevenheless, there are many millions, particularly in the Himalayas or Andes, for whom heating is essential for survival, or is needed for a tolerable existence.
Mountain people have been largely overlooked in the design of household energy programmes and stoves and, as a result, space heating has never figured prominently in studies of energy policy.
Where stoves provide a heating function, they are often in rooms which are badly ventilated, in order to prevent heat loss. The resulting exposure to severe indoor air pollution is known to be bad for the health of both the stove users and other family members. Although the use of chimneys can help in reducing many of the harmful components in the room, they are not a cure for smoke problems. Fires may bum faster due to the improved draught, heat will be lost through them and fuel will be wasted.
Biomass use in mountain areas
As in almost all developing countries, biomass is the main source of energy for cooking and space heating and it is expected to remain so for the foreseeable future. The reasons are:
· A reliable supply of biomass
is usually locally available.
· It is almost always the cheapest available fuel if the fuel has to be bought.
· Use of biomass is traditional and women are skilled in fuel
· Stoves have been designed or adapted to the local biomass fuels.
· There may be no other fuels available.
Meeting household energy needs
Stoves with several uses
Some combined cooking and space heating stoves have been developed with the aim of saving fuel, reducing environmental impact and yielding a range of benefits to users, particularly savings in time, work and money. Besides being able to afford an improved stove, the need for information about its good and bad points needs to be given to the user. If users do not know about the benefits and problems associated with a new stove they will often stay with the traditional stove.
Typical stove used in high regions for cooking and space heating
Cookstoves often have several functions; cooking, space heating, lighting, crop and fuel drying. social gathering etc. To succeed. stove development needs to take account of the local conditions, including house and stove construction materials and skills and the effects of weather. Social and cooking habits, affordability, complexity of the stove and ease of maintenance and repair need to be carefully checked. The materials used for stove construction should be obtained locally in view of the extreme difficulty of transportation. Stoves need to suit the available fuels, pot sizes and use (cooking on high heat, simmering, baking, special food preparations etc.).
The need to design stoves which perform several functions is often overlooked by stove programmes. In mountain areas, space heating is an important energy need which merits far more emphasis in energy policy and research.
The most straightforward way to provide space heating from a stove is to use the chimney as a heat radiator. This means routing the chimney through the room/s so as to transfer the heat from the exhaust gases to the air around the chimney. In many places, considerable local expertise on chimneys is available and can be used at the design stage.
The Chinese under-floor heating system, the 'Kang-Lianzao' bed stove (BP.29, page 33), may be appropriate for cold mountain regions elsewhere.
Solar energy for space heating
Active solar systems collect energy from the sun and then move the energy to storage or directly to the user by means of a transfer medium such as water. They perform well for domestic water supply but offer little for space heating. Adoption rates are very low due to the initial cost for the householder.
Passive solar designs have produced promising results in demonstration projects all over the world, notably on the high plains of Bolivia at an altitude of over 4000 metres. Similar work has been carried out by the LeDeG organisation in Ladakh. Passive solar design employs the principles of positioning buildings to achieve maximum winter insolation (incoming energy from the sun) whilst minimising heat losses. Window design has also been developed to a fine an. The trombe wall, which acts as a heat store during the day and gives out heat to the dwelling during the evening, is a simple device which also shows impressive results.
However promising the technical performance of these systems appears, the obstacles to the spread of solar designs are formidable. In particular, finding ways of influencing the design of new dwellings is a real barrier to the technology. The challenge of changing existing houses to adopt elements of solar design may be too great. In general, the costs of incorporating solar design into dwellings will restrict their spread beyond any but the most wealthy communities or for communal buildings.
Stove programmes are often driven by the supply of the technology itself. Too frequently, they take a narrow view of stove development without considering other options which could achieve the same goals, such as better maintenance of traditional stoves or improving house construction.
Kang-Lianzao bed stove
During research into improved electric stoves for rural areas of Nepal carried out over the last six years, ITDG worked in several Himalayan communities. The electric stove incorporated a heat store made from stones. During one phase of the work, the local team tried to improve the insulation to this heat store, thereby saving most of the heat generated for cooking. They soon learned that the space heating characteristic of the new stove design was valued much more highly by users than the project team had initially imagined.
It is rare to find credit facilities and training programmes provided to local entrepreneurs and manufacturers in mountain communities. Availability of local materials for constructing space heating stoves is very limited and the import or transport of these materials increases the cost of stove manufacture.
Strategies for promoting heating stoves have to be different from those used for cooking stoves because of the varying seasonal and local requirements for heating energy.
· A stove programme must be integrated with related programmes such as housing improvement, health and sanitation or rehabilitation work following disasters.
· It should be used to promote traditional skills and technologies and use local institutions.
· improved stove dissemination should lit in with the financial reality of households rather than the economic aims of governments.
· Technology research and development for solar systems should concentrate on cost reduction, for example, simple approaches using locally available building materials may be suitable for reducing the heat loss from the building.
Overall, a far greater understanding of the priorities of mountain communities is required. Lessons from the commercial spread of stoves in many countries have shown that successful stoves arc those which meet the expectations of their purchasers rather than the ambitions of their designers. A simple point, but fundamental to bringing mountain communities more directly into work on household energy.