Alternative energy in Trans-Himalayan Cold Deserts

Ladakh is the northernmost region in the Jammu & Kashmir State of India. It can be characterized as a 'Trans-Himalayan mountain desert' with minimum temperature in winters -20°C to -35° and hardly any rainfall. Leh, the capital, is located at 11,000 feet (3500m).

The cold climate of Ladakh generates a high demand for heating. But lack of rainfall makes trees and thus firewood a scarce resource. However, its average of 300 days of sunshine per year makes this region especially suited for solar energy.

Since 1994 SECMOL has developed solar heated buildings and other forms of solar energy to make its campus at Phey self-reliant. Having gained a lot of experience from this process we have started a commercial section, Sheyson Solar Earthworks, for design and construction of solar buildings around Ladakh.

SOLAR POWER ON PHEY CAMPUS

Our campus outside Leh at Phey, established in 1994, is now almost completely solar powered. We use solar electricity for all our electrical and pumping needs. The campus has two solar cookers and a low tech water heater for bathing. Most noteworthy are the campus buildings, which use passive solar heating to keep warm even in the coldest months of winter.

Solar panels

We have four arrays of 16-24 panels each generating electricity for lighting, computers and TVs. On sunny days we can even use carpentry and soldering tools. These also power pumps to lift water from the Indus for irrigation of fields and trees. Nothing would grow here in Ladakh without irrigation, and the nearby spring is only enough for the kitchen and bathing, not enough for the trees and gardens.

The power is stored in 16 solar batteries, and stores enough to run for three days of cloudy weather.

 

Solar cookers

In our campus community kitchen we use two concentrating dish-type solar cookers to cook most of our food directly on the sun's rays. They were assembled in 1997 by a group including SECMOL students at a workshop at LEDeG under Swiss direction.

This cooker is a large parabolic reflector made of household mirrors, that focuses the rays of the sun to a secondary reflector under big pots inside the kitchen. This very efficient design gives energy equal to a large gas burner, and saves a lot of money while preserving the environment.

Solar cooker.

SECMOL solar water heater

For the campus bathrooms we have designed a very low cost solar water heater from basic materials easily available. The cost of one 100 litre solar heater is Rs 3,500, whereas commercial ones cost Rs 25,000 per 100 litre.

A great advantage of this design over expensive commercial models is that it has no pipes inside that can freeze and break, so it can be used all winter without draining. Since it is basically a large shallow tray, if it freezes overnight, nothing breaks, and in the sunny morning it simply melts and starts warming up again.

 

Materials:
a. Aluminium sheet painted black to absorb the sun's heat.
b. Greenhouse plastic to cover it.

The sides of the aluminium sheets are bend up to form a large tray two inches deep. It is covered with a small plastic greenhouse. In the winter it is inside a double layer of plastic. It is filled with water in the morning, and by 12 noon it makes 100 litres of 45°C water.

SECMOL buildings and passive solar design

SECMOL buildings are completely independent of conventional heating methods such as firewood stoves or electric heaters. They are designed to absorb heat from the sun and to store it within the building for as long as possible. This method is called 'passive solar design' as opposed to active designs which use circulating water pipes, air blowers, or other moving parts. This method has indeed proved very effective. Because of its passive solar design the SECMOL buildings have stayed warm and have not needed any external heating in the last 10 years — even when the minimum outside temperatures falls down to –25°C.

Running solely on passive solar heating, the nnhhxx temperature in the main building at SECMOL Campus has been:

Average evening temperature in winter: +14°C
Minimum in a normal winter: +10°C
Minimum observed in 7 years: +8°C

In the main building at Phey Campus the stair wells have geranium and other plants blooming and flourishing even in January when the minimum outside temperature is -25°C.

The main features of the buildings that keep them warm are:

• South facing windows, as the sun stays low in the southern sky in winter.
• A greenhouse on the south side in winter to capture more of the sun's heat.
• The greenhouse is removed in springtime to prevent overheating.
• Thick earthen walls and floors (thermal mass) to store the collected heat.
• Good insulation in ceilings, outer walls and under the floor to keep this heat.
• Low cost local materials like mud & rocks — cheap and best.
• We build for natural lighting so no electricity is needed throughout the day.

Glazing or plastic film towards the south

In winter, huge plastic sheets come down and make a big greenhouse which works as a solar heat collector for the building. The plastic stays rolled up and tucked away in the summer to prevent overheating. This ultraviolet stabilised plastic is commonly used for agricultural greenhouses in Ladakh.

In some of our newer buildings we use multi-walled poly carbonate structures that fold up in summer and fold down in winters. These are stronger than the plastic sheets, but costlier.

A bonus feature of the plastic covering is that they make excellent greenhouses, which can grow vegetables and flowers in the Ladakhi winter.

High thermal mass in the walls and floors

We build our buildings three feet below the ground level on the north side. The building benefits from the stability of earth’s temperature at that depth, which is relatively warm in winter and cool in summer. This also helps us get the building material — earth — right on site. The three feet of earth we dig out ultimately becomes the walls of the building.

The walls are build of rammed earth layers. It is a most eco-friendly way because the building material comes right from the site and is not transported over hundreds of miles. Similarly, when the construction is finished, there is no debris left to be thrown away — no addition, no subtraction. Earth buildings are the warmest in winter, coolest in summer, and they also moderate the humidity of the building.

The technique of rammed earth consists of casting huge bricks on site, in a frame made of planks. Sand and clay are mixed in the right amounts to get a very strong constitution. It is then filled in the frames and rammed with pounders.

The earth walls are very thick. They are not just structural (to take load) but also have an essential function as the heat bank (thermal mass). They absorb the excess solar heat during the day and release it to the room at night. The same properties also make rammed earth buildings the coolest buildings in summer.

Rammed earth is an ancient technique used for hundreds of monasteries, castles and forts around Ladakh. These structures, unprotected and exposed to the elements, have survived for hundreds of years.

While we have been resurrecting this method in Ladakh, we are pleasantly surprised to know that there is a resurgence of this technique in many western countries in Europe, North America, and especially in Australia.

Insulation in ceilings, outer walls and under the floor

Insulation is the key to retaining the heat that is collected during the day. But it does not need to be very expensive modern materials. The wood waste generated during the construction is filled in the ceiling to stop heat loss through the roof.

Insulation below the floor is also important. Layers of various sizes of rocks create insulating air-pockets between the rocks. A top layer of gravel and cement acts as a heat bank.

Sometimes the top layer of the floor is lined with slates from the nearby mountains. This reduces the use of cement, and the slates also become a thermal mass or heat bank as they are now cut off thermally from the cold ground.

This kind of floor absorbs the excess heat during the day and releases it during the night. Normally floors are an area of big heat loss.

The outer walls are insulated by a jacket wall outside the main structural wall. The six inch gap between the two walls is filled with low cost insulation: saw dust, wood shavings or sometimes paper and plastic garbage like bottles and bags from the city. Sometimes we have also used cow dung as an insulating plaster. Mixed with the right amount of earth and clay, it makes a strong and thermally effective plaster.

If comparing 'thermal conductivity' (insulation property) of common Ladakhi building materials, you find that mud is the best:

1 ft mud wall = 2 ft concrete = 4 ft stone = 1.5 inch of saw dust. = 1 inch of Thermocol, rockwool etc.

 

Natural lighting — the sun

Windows and skylights ensure that no place in the building needs electric lights in the day.

Sheyson Solar Earthworks

In 2000 we founded a commercial, income-generating section, Sheyson Solar Earthworks, that benefits from our many years of experience building solar buildings. Sheyson builds solar buildings on turn-key contract for private homes, the government, NGOs, and the army. The profits from Shesyon Solar Earthworks support educational reform, environmental awareness activities etc. in the region where it works.

In addition to this it trains village youth as 'Barefoot Solar Engineers'. The first batch of four students will join staff in 2007.

For the benefit of humans and all living beings we plan to launch the Shesyon concept in Kargil, Lahoul-Spiti (Himachal), Uttaranchal, Sikkim, Arunachal etc. in India, and Central Asia, Afghanistan, Northern Areas of Pakistan, Nepal, Tibet, Mongolia and other cold and sunny places in the world.

Sheyson projects

Sheyson has already completed many solar projects around Ladakh. In 2005 we completed the Army Goodwill Headquarters in Leh.

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Contact Sheyson Solar Earthworks.