Solar greenhouses in Ladakh

Thanks to Thomas Mansouri for this article on the concept of solar greenhouse developed by the NGO GERES in India - http://geres.free.fr

The climate is much more severe in Ladakh than in Europe; the temperature can descend as far as -30°C during winter nights. Despite this, the region enjoys almost 300 days sunshine a year, which constitutes a formidable source of free energy.
Combining local know-how and passive solar architecture techniques, GERES has developed a greenhouse suited to local conditions, which can be built from materials available on the spot (except for the transparent plastic cover).

The south facing exposure, the angle of the transparent cover, the insulation of the walls (brick or earth, lined) and of the roof with straw – everything has been designed to store a maximum amount of solar energy during the day time and release it passively during the night, to avoid freezing, and withstand the abundant falls of snow.

To these basic principles should be added aeration techniques (insulated windows, on the roof and on the west wall) to avoid overheating: when the sun shines during the day, temperatures in the greenhouse can be in excess of 30°C, even in the middle of winter, which is not good for the vegetables or for water consumption (always a rare commodity in winter).

A few examples
For families who are still largely dependent on agriculture, the produce from a greenhouse can allow them to increase their income by 50% (by selling their vegetables in winter, when scarcity sends the prices soaring).
In the coldest areas, the greenhouses are also used in winter for taking baths, working on crafts, or as a place for the elderly or convalescing people to relax.
The production of plants for planting in the fields, early in the season, is an excellent way of prolonging the summer – and in a location where the growing season in the fields lasts only four months, each week gained is important!