Wind Power
Submitted by Rolf Albern on Wed, 01/27/2010 - 11:01
China may have been the birthplace of the windmill. The earliest actual documentation of a Chinese windmill was in 1219 A.D. by the Chinese statesman Yehlu Chhu-Tshai. It is assumed to have been used primarily for grain grinding and water pumping.
A vertical axis system called panemone device was developed in Persia about 500-900 A.D. It was apparently used for water pumping. The first document design features vertical sails made of bundles of reeds or wood which were attached to the central vertical shaft by horizontal struts.
Grain grinding windmills consisted of a grinding stone affixed to a vertical shaft driven by a horizontally mounted wind rotor. The mill machinery was commonly enclosed in a building. Wooden cog-and-ring gears were utilized for the vertical axis rotor to drive the horizontal axis grindstone.
Rotor designs have their roots in sailboat design from which early knowledge of wind forces was learned by experimentation. On the island of Crete sail-rotor windmills are still used to pump water. Steel bladed versions of these pumps were used through out the American heartland in the late 1800's. By 1970 over six million small windmills were installed in the U.S. primarily for pumping water. Raised water towers were a common storage method that provided on demand water pressure delivery. By the mid-1920's Parris-Dunn and Jacobs were major suppliers for wind-electric to the mid-west and Great Plains area. The early success of the Midwest wind turbines actually set the stage for the possibility of more extensive wind energy development in the future.
The development of bulk-power, utility-scale wind energy conversion systems was first undertaken in Russia in 1931 and operated for two years on the Caspian Sea. Experimental wind plants were tried in US and Europe from 1935 until 1970 but failed to be practical.
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