Wind power
has been used by humans since antiquity. Great oceans were crossed to explore
unknown lands by putting up sails against the wind. At home, wind drove
machines that ground grains between stones to produce flour and pumped water
from rivers and wells. The first practical windmills went up in Persia,
possibly as early as the 5th century AD. These were horizontal windmills with
long vertical driveshaft with six to twelve rectangular sails covered in reed
matting or cloth, and they were used at homes as well as in grist milling and
sugarcane industries. The use of windmills became widespread across the Middle
East and Central Asia, and later spread to China, India and the rest of Europe.
Some of these earliest examples of vertical windmills can be seen in the town
of Nashtifan, where they are still in use.
Nashtifan
is a town located in the southern parts of Khorasan Razavi province, in Iran,
20 kilometers away from Khaf and 30 kilometers away from the border with
Afghanistan. One of the main characteristics of the area is the strong winds
that blow across it, causing it to initially be called Nish Toofan or “storm’s
sting”. As a result of the natural elements in the area, windmills have been
part of the region’s industrial creativity and have been used throughout many
centuries.
There
are approximately 30 of windmills scattered thought the area and can reach
heights of 15-20 meters. The windmills are believed to have been erected during
the Safavid dynasty and are generally constructed out of clay, straw and wood.
The wooden blades of these windmills turn the grinding stones in a room made of
clay. Each of the windmills consist of 8 rotating chambers with each chamber
housing 6 vertical blades (essentially a wall with slits). Once the chambers
begin rotating by the force of the wind, it results in the turning of the
windmill’s main axle which was in turn is connected to grain grinders. The
vibrations created by such rotation gradually shifts the grains from their
holding container to the grain grinders. The end result is that the grain is
ground into flour.
The
windmills at Nashtifan have a horizontal design, i.e. the driveshaft is
vertical and the wind panels rotate horizontally. This is the first known
documented design and not very efficient compared to today’s vertical windmills
where the wind blades rotate vertically. The downside to horizontal windmills
is that because the wind panels rotate horizontally, only one side absorb the
wind energy while the other half of the device have to essentially go against
the wind current and thus waste energy in order to do so. As a result the
blades can never move faster than, or even at, the speed of the wind.
The
drawback in the design is compensated by the immense wind energy that is
available in this area. At Nashtifan, speed of the wind often reach 120
kilometers per hour.
In
2002 the windmills of Nashtifan were registered as a national heritage site by
Iran’s Cultural Heritage Department.
Very cool!
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