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Cheap solar chimney
This solar chimney can be made with low cost materials and a little labor. It has no moving parts. The sunnier the day, the more effective it is.
A black painted, 150 mm diameter metal tube stands out of the roof, 6 to 8 meters high; the air inside gets hot and rises creating an airflow which draws cool air into the building, possibly through an Evaporative cooler.
In order to have the air swirling (to improve heat transfer between the air and the pipe) you also need a slotted cylinder 200-300 mm in diameter, welded to the bottom of the black tube. The slots must be vertical and have their rims bent inwards so the air enters the chimney with a circular motion..
Alternative design idea
In the Hexayurt, the aspiration device could be used alone, with a wet cloth fitted on an air inlet near the ground, using the evaporation to cool and moisten the incoming air.