A clean energy technology for converting solar energy into heat for warming homes.
Passive Solar House technology is documented by Sustainable Land Management Project/HELVETAS Swiss Intercooperation with financial support of Swiss Agency for Development and Cooperation.
Households in Bayman Centre experience very cold winters and meeting household energy needs for the Bamyan population is challenging. They mostly rely on unsustainable solutions such as burning manure or mountain shrubs. Shrub harvesting for firewood is a major cause of land degradation in the province. Fuel expenses also deplete the financial resources of an already impoverished population. Also, due to the intense cold, very few activities are possible during the winter. To overcome the challenges of heavy dependence on biomass for winter heating and to improve living conditions, many families in Bamyan Centre are adopting the passive solar technology for improving their living conditions, while reducing pressure on environment.
Passive solar technology captures sunlight in a room or building, and converts that energy into low-temperate heat. It provides an efficient mean of capturing the sun's energy, reducing the need for fuel wood and coal for heating.
(1)The passive solar house (PSH) technology has significant economic, socio-cultural and environmental benefits. They are as follows:
(2)reducing the reliance on shrubs and other heating materials; saving expenditure on fuel (aprox.25,000 Afghani/year) and the time usually spent on harvesting bushes;
(3)provision of extra space in the house for washing/drying cloths, bathing, social activities, play and study area, space for vegetable crops for home consumption; savings due to this technology offset the high initial investment cost;
(4)improved health due to less exposure to cold;
(5)reduced pressure on environment. The technology contributes to re-greening of common lands or rangelands where fewer shrubs are collected (uprooted) for firewood.
PSH should have a Southern exposure to take maximum advantage of the sun for daylight and passive solar heating. Most of the houses in Bamyan have southern exposures. The PSH is generally used for 6 months (November to April).
Although the technology was introduced in Bamyan by GERES, an International Non-Governmental Organization, many families have replicated it without any external support.
The main purpose of Passive Solar House technology is to make use of the solar energy for heating homes. As a result, the need for shrubs and coal for home heating is reduced significantly. The technology contributes to re-greening of common lands or range lands on which shrubs are harvested (uprooted) for firewood. Barat Ali's family bought about 60 donkey loads of shrubs per year for winter heating purposes. They did not have to do that after this technology was implemented by the PSH owner. The technology also contributes to the well-being of all family members, especially of women, who can do their household chores, and children who often got sick due to cold exposure.
The PSH presented here was established in September 2013 before the onset of winter. A transparent plastic sheet, metal pipes, wires and ropes to hold the plastic are used for construction work. Metal pipes were purchased from Kabul by the owner.
The PSH measures 17 m in length, 5 m in width and about 4 m in height. However, the PSH may vary from one house to another. The factor to consider is that the PSH should have long area to capture maximum sunlight. The upper part is slopping (about 30% gradient) to drain the water and snow. Local semi-skilled labor and skilled mechanic for welding the pipes were employed for construction works.
Approximately 45,000 Afghani/790 USD was spent on the construction of this PSH. The owner made significant investment. He purchased the pipes and plastic contributing approximately 70% of the costs. Plastic sheets, which are available on the market in Bamyan, are not of very high quality and have to be replaced each year. If the used plastic sheet is not too damaged, it is placed on roofs to protect from snow water/rain seepage. Otherwise, it is simply thrown away, which is not an environment friendly practice.
According to the PSH owner, a possibility for improvement is to use good quality wooden frame instead of pipes so that the plastic sheet can be kept intact by nailing it to the wooden frame. Using wooden frames may also reduce the cost of the technology, making it more affordable for poor families. Provision for ventilation is an aspect which needs to be considered while constructing PSH.
Bamyan province is a remote province of Afghanistan with high poverty rate. It has a temperate and arid climate. During winter, temperatures can drop below minus 22 degrees. Summer temperature can reach up to 34 degrees in the month of July. The average annual rainfall in the area is about 230 mm and some years can be very dry.
90% of the population relies on subsistence agriculture for their livelihoods and off-farm activities are marginal.
Bamyan Center / Dashte Esakhan
- < 0.1 平方千米（10 公顷）
Total area covered by the SLM Technology is 0.00027 km2.
The PSH and house areas are 85 and 270 square meter, respectively.
The PSH owner saw the technology applied by others and replicated it without any external support. The technology has been promoted by GERES (an International NGO) in Bamyan.
Major land use problems (compiler’s opinion): Degradation of common lands due to shrub harvesting for firewood and overgrazing by sheep and goats.
Major land use problems (land users’ perception): Land degradation due to uprooting of shrubs required for domestic purpose like heating homes during winter and cooking.
Constraints of Infrastructure (House): Lack of alternative energy resources. Heavy dependence on biomass for burning.
Longest growing period in days: 180, Longest growing period from month to month: April-September
Specification of other structural measures: Passive Solar House
Main causes of degradation: over-exploitation of vegetation for domestic use (Shrubs for fuel wood), overgrazing (Mainly sheep and goats), governance / institutional (Specially relating to common lands), lack of alternative energy options
Secondary causes of degradation: droughts, population pressure
Technical specification of South facing Passive Solar House constructed by the house owner comprising white plastic sheet, pipes for framers, string tied outside to secure plastic. Entrance gates.
Location: Dashte Esakhan. Bamyan Centre
Technical knowledge required for field staff / advisors: moderate
Technical knowledge required for land users: moderate
Main technical functions: improvement of ground cover
Structural measure: Passive Solar House
Height of bunds/banks/others (m): 4
Width of bunds/banks/others (m): 5
Length of bunds/banks/others (m): 17
Construction material (other): Plastic sheet, metal pipes, wires
SLM Project, Helvetas, HELVETAS Swiss Intercooperation Afghanistan
|1.||Purchase material from Kabul||September 2013|
|2.||Construction of PSH using 4 semi-skilled workers for 3 days and one skilled mechanic||September 2013|
Duration of establishment phase: 1 month(s)
|1.||Maintainance - plastic sheet||As required|
|2.||Replacement of plastic sheet every year|
Machinery/ tools: Plastic Sheets, Pipes, Wires, Generator, Welding Machine
The prices in Afghani are for September 2013. The exchange rate which was used for the conversion of US$ to Afghani was 1 US$ = 57 Afghani.
Pipes is the most expensive part of this technology
- < 250毫米
- > 4,000毫米
Most rainfall in spring (April and May) and also there is snow.
Thermal climate class: temperate. Bamyan has cold winter (temperatures can fall up to -22 degree C) and temperate summer.
- 0-100 m a.s.l.
- 101-500 m a.s.l.
- 501-1,000 m a.s.l.
- 1,001-1,500 m a.s.l.
- 1,501-2,000 m a.s.l.
- 2,001-2,500 m a.s.l.
- 2,501-3,000 m a.s.l.
- 3,001-4,000 m a.s.l.
- > 4,000 m a.s.l.
- 非常深（> 120厘米）
Land users applying the Technology are mainly common / average land users
Difference in the involvement of women and men: All the PSH construction work is done by men.
Population density: 10-50 persons/km2
Annual population growth: 2% - 3%
100% of the land users are average wealthy.
- < 0.5 公顷
- 0.5-1 公顷
- 1-2 公顷
- > 10,000公顷
Well belongs to the house owner
For winter season
Time saved in shrubs collection, burning Bukharis stoves for house warming, going out for daily chores like drying clothes, etc...
Reduced expense on fuel (wood and coal)
Due to less consumption of coal and shrubs
Off-season vegetable production for self consumption
Harvested 5 times during winter/spring
Energy saving (coal bags)
Less use of coal for winter heating
Due to increased fresh winter vegetable production. Cash saved can be used for buying food items.
Women, men and children are less exposed to severe cold. Also consumption of vegetables grown in the PSH contributes to food diversity and health. PSH also protects chimney smoke from outside entering the house.
PSH used for social meeting, children play and studies, washing/drying clothes, bathing etc.
In terms of reducing shrub cutting through alternative energy options. Others see and learn.
contribution to human well-being
The technology has contributed to less expenditure on fuel, improved health and has created socio-cultural opportunities.
As PSH has sloping top without any proper outlet for concentrated runoff
As the family can grow certain vegetable crops and flowers inside the PSH during winter time.
Because of less burning of coal and shrubs
Increased vagetation cover
Due to less extraction of shrubs for firewood for winter heating
Reduced soil erosion
|Intense sun light||不好|
Pipes should be replaced by wooden frames because they get heated up and can damage the plastic. Also, using wooden frames may reduce the cost.
The cost of the PSH can be covered in 2 years time. This is only in financial terms but if we analyse the overall economic benefits considering health and ecological benefits, the benefits compared with establishment costs will be more.
100% of land user families have adopted the Technology without any external material support
30 land user families have adopted the Technology without any external material support
There is a moderate trend towards spontaneous adoption of the Technology
|Multiple benefits for the family - less expense for fuel, children can play inside in warm climate. It is also a good space for social meetings.|
|PSH has multiple benefits: house warming using clean energy, less expenditure on fuel for winter, extra room for various activities (like studies, playing, washing, drying clothes, warming water, social meetings), less use of shrubs.|
|Due to PSH technology, families dependency on shrubs for firewood is reduced which leads to improved land management.|
|Convinced by the benefits of PSH technology, many families with financial resources have constructed it without seeking external support.|
|Metal pipe is not good for frame because the plastic sheet cannot be nailed to it so that it does not get blown away by wind.||Use of wooden frame.|
|Distance between pipes is more.||More pipes needed to reduce that gap.|
|The air moisture can increase in the PSH as well as in the other parts of the house.||The door and if possible the window of the PSH should be opened for some minutes during the day.|
|PSH does not have proper ventilation.||Construction of a ventilator.|
|The poor households cannot apply it due to high establishment cost.||Use of low cost wooden frame and some incentives to the poor families for establishment.|