Windmill

Made of six to 12 sails covered in reed matting or cloth material, these windmills were used to grind grain or draw up water.

[17] The Persian geographer Estakhri reported windmills being operated in Khorasan (Eastern Iran and Western Afghanistan) already in the 9th century.

[20] By the 11th century, the vertical-axle windmill had reached parts of Southern Europe, including the Iberian Peninsula (via Al-Andalus) and the Aegean Sea (in the Balkans).

[21] A similar type of horizontal windmill with rectangular blades, used for irrigation, can also be found in thirteenth-century China (during the Jurchen Jin dynasty in the north), introduced by the travels of Yelü Chucai to Turkestan in 1219.

These early modern examples seem not to have been directly influenced by the vertical-axle windmills of the medieval period, but to have been independent inventions by 18th-century engineers.

[23] The horizontal-axis or vertical windmill (so called due to the plane of the movement of its sails) is a development of the 12th century, first used in northwestern Europe, in the triangle of northern France, eastern England and Flanders.

[25][26] The earliest certain reference to a windmill in Northern Europe (assumed to have been of the vertical type) dates from 1185, in the former village of Weedley in Yorkshire which was located at the southern tip of the Wold overlooking the Humber Estuary.

The spread of tower mills came with a growing economy that called for larger and more stable sources of power, though they were more expensive to build.

These are also fitted to tail poles of post mills and are common in Great Britain and English-speaking countries of the former British Empire, Denmark, and Germany but rare in other places.

Around some parts of the Mediterranean Sea, tower mills with fixed caps were built because the wind's direction varied little most of the time.

The smock windmill design included a small turbine in the back that helped the main mill to face the direction of the wind.

Later mill sails had a lattice framework over which the sailcloth was spread, while in colder climates, the cloth was replaced by wooden slats, which were easier to handle in freezing conditions.

[34] The jib sail is commonly found in Mediterranean countries and consists of a simple triangle of cloth wound round a spar.

[citation needed] In France, Pierre-Théophile Berton invented a system consisting of longitudinal wooden slats connected by a mechanism that lets the miller open them while the mill is turning.

In the twentieth century, increased knowledge of aerodynamics from the development of the airplane led to further improvements in efficiency by German engineer Bilau and several Dutch millwrights.

[citation needed] Earlier multiple-sailed mills are found in Spain, Portugal, Greece, parts of Romania, Bulgaria, and Russia.

Across the Netherlands, windmills were placed in mourning positions in honor of the Dutch victims of the 2014 Malaysian Airlines Flight 17 shootdown.

Post mills sometimes have a head and/or tail wheel driving the stone nuts directly, instead of the spur gear arrangement.

[38] In the 14th century, windmills became popular in Europe; the total number of wind-powered mills is estimated to have been around 200,000 at the peak in 1850, which is close to half of the some 500,000 water wheels.

The first wind turbines were built by the end of the nineteenth century by James Blyth in Scotland (1887),[42] Charles F. Brush in Cleveland, Ohio (1887–1888)[43][44] and Poul la Cour in Denmark (1890s).

By the 1930s, windmills were widely used to generate electricity on farms in the United States where distribution systems had not yet been installed, built by companies such as Jacobs Wind, Wincharger, Miller Airlite, Universal Aeroelectric, Paris-Dunn, Airline, and Winpower.

The development of these 13 experimental wind turbines pioneered many of the wind turbine design technologies in use today, including steel tube towers, variable-speed generators, composite blade materials, and partial-span pitch control, as well as aerodynamic, structural, and acoustic engineering design capabilities.

[48][49] While such changes increase their power output, they subject the components of the windmills to stronger forces and consequently put them at a greater risk of failure.

The remainder of the shell, not supported by the spars or laminated at the leading and trailing edges, is designed as a sandwiched structure, consisting of multiple layers to prevent elastic buckling.

Hansen, where the product manager informed, that they have transported approximately half of the wings they have received since 2012 to Reno Nord's landfill in Aalborg.

[58] Since 1996, according to an estimate made by Lykke Margot Ricard (SDU) in 2020, at least 8,810 tonnes of the wing scrap have been disposed of in Denmark, and the waste problem will grow significantly in the coming years when more and more wind turbines have reached their end of life.

According to the SDU lecturer's calculations, the waste sector in Denmark will have to receive 46,400 tonnes of fiberglass from wind turbine blades over the next 20–25 years.

[57][59] In the United States, worn-out wind turbine blades made of fiberglass go to the handful of landfills that accept them (e.g., in Lake Mills, Iowa; Sioux Falls, South Dakota; Casper).

[61] Windmills were later used extensively in Europe, particularly in the Netherlands and the East Anglia area of Great Britain, from the late Middle Ages onwards, to drain land for agricultural or building purposes.

A tower-top gearbox and crankshaft convert the rotary motion into reciprocating strokes carried downward through a rod to the pump cylinder below.