1254 GMT June 15, 2021
Along the southern edge of town, a towering 65-foot-tall earthen wall shelters residents from the abrasive gales. The high wall houses two dozen mostly functional vertical axis windmills that date back to ancient Persian times. It’s estimated the structures, made of clay, straw, and wood, are around 1,000 years old, used for milling grain into flour, atlasobscura.com wrote.
The area is known for its uniquely powerful winds, and in fact the name Nashtefan is derived from words that translate to “storm’s sting.” The village of Nashtefan is in the Khaf County in Khorasan Razavi Province. During turbulent winter months the handcrafted wooden blades whirl with a surprising velocity and power grindstones in a marvel of engineering and passive ventilation. With periodic repairs to turbines, these well-built earthen structures could go on for centuries so long as there are caretakers willing to maintain them.
The tall walls framing the windmills both support the turbines, and funnel the airflow like the elliptical throat in a primitive wind tunnel. Unlike European Don Quixote-style windmills, the Persian design is powered by drag as opposed to lift. And since the blades are arrayed on a vertical axis, energy is translated down the mast to the grindstone without the need for any of the intermediary gears found on horizontal axis windmills.
The vertical axis design is probably similar to the windmills that were invented by the Persians around 500 BCE – a design that slowly spread through the world and which was later adapted by the Dutch and others, according to nationalgeographic.com.
Each of the windmills of Nashtefan is comprised of eight chambers, with each chamber housing six blades. As the area’s strong, steady wind enters the chambers it turns the blades, which then turn grindstones. The structures reach up to about 65 feet in height.
With the ample winds, the devices can readily glean enough power from the wind to turn a stone. If they were hooked up to a generator, they would produce only a small amount of electricity, possibly not even enough for a lightbulb. Today’s power-harvesting turbines have more efficient designs that take advantage of lift to attain higher speeds, and therefore produce much more power.
Ali Mohammad Etebari serves to keep the historic Nashtefan Windmills turning.
In 2002, the windmills were recognized as a National Heritage Site by Iran.
The windy pride of Nashtefan, the structures are doted on by an amiable custodian named Ali Mohammad Etebari. Etebari serves as the last keeper of the ancient tradition. Now elderly, Etebari has dedicated his life to keeping the town’s few dozen historic windmills turning. As the last survivor of the Nashtefan Windmills, his name was added to the UNESCO’s list of Living Human Treasures two years ago.