The windcatchers of Yazd

Air conditioning with no power, and it kept ice through a desert summer

A badgir is a tower that air conditions a building with no power at all, and Yazd is full of them. Two things drive it. Wind pressure does most of the work. The stack effect does the rest, warm air rising and pulling cooler air in behind it. The towers in Yazd are all four or eight sided so they work whatever direction the wind is in; where the wind reliably comes from one side, as at Meybod nearby, they are built short with a single opening. The tallest surviving one stands at the Dowlatabad Garden. It works better combined. Run the intake over the water in a qanat tunnel and the air arrives cooled by the water and the surrounding earth, or put one over a yakhchal, an ice house, and it circulates air across stored ice so it melts only slowly. A desert city kept ice through the summer centuries before refrigeration.