199 results about "Windmill" patented technology

A windmill is a structure that converts the energy of wind into rotational energy by means of vanes called sails or blades. Centuries ago, windmills usually were used to mill grain (gristmills), pump water (windpumps), or both. There are windmills that convert the rotational energy directly into heat. The majority of modern windmills take the form of wind turbines used to generate electricity, or windpumps used to pump water, either for land drainage or to extract groundwater. Windmills first appeared in Persia during the 9th century, and then later appeared across the Middle East, Central Asia, China, India, and Europe.