Cheap solar chimney
This solar air conditioner can be made with low cost materials and a little labor. It has no moving parts. The sunnier the day, the better the efficiency.
A black painted, 150 mm diameter metal tube stands out of the roof, 6 to 8 meters high ; the air inside hottens and rises swirling, just like in a storm. In the center of the vortex thus created, the air gets cooler. A smaller (40 mm dia.) vertical metal tube is fitted inside the black tube, right in the center. An elbow sucks the hot air from the top of the building, the hot air gets cooled in the vortex and falls from the vertical part of the small tube.
In order to have the air swirling the right direction, 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 the right direction, i.e. counterclockwise in the northern hemisphere.
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 Peltier effect to cool and moisten the incoming air.
The original article from Ekopedia, in French language but with the drawings