What is a Windmill? – Definition, Types, & Uses

A windmill is a structure that converts wind power into rotational energy by using vanes called sails or blades, specifically to mill grain (gristmills), but the term is also extended to windpumps, wind turbines, and other applications. The term wind engine is sometimes used to describe such devices.

In this article, we discuss What is windmill, the history of windmills and how they evolved into modern designs, as well as how they work.

What is Windmill?

A windmill is a device for tapping the energy of the wind by means of sails mounted on a rotating shaft. The sails are mounted at an angle or are given a slight twist so that the force of wind against them is divided into two components, one of which, in the plane of the sails, imparts rotation.

The power of the wind was first used by sailors who understood lifting and could use the power of the wind through sails. This knowledge led to the development of the first vertical axis windmill used by the ancient Persians and Chinese to grind grain and pump water.

A windmill is an environmentally friendly machine because it runs on renewable energy and has no emissions that can pollute the environment.

Early European windmills with horizontal axis systems formed the basis for current wind turbine technology for power generation. For more information about wind energy check out What is wind energy?

Windmill history

The earliest known wind powered grain mills and water pumps were used by the Persians in AD 500-900 and by the Chinese in AD 1200. The first US-made windmill was designed by Daniel Halladay, who started inventing windmills in a Connecticut machine shop in 1854.

Wind energy has been used for thousands of years, starting with the invention of sailboats as the first and most obvious example of the use of wind energy.

The windmill was hugely successful in pumping water to farms and ranches on the expanding western border, so Halladay moved its operations to Illinois.

In addition, the windmill played a key role in expanding the railways, as water was needed to run the early steam-powered engines.

Eventually, more than 1,000 factories, small and large, started operating water-pumping windmills, with one company at the height of the market selling nearly 100,000 in a year.

In the 19th century, America restructured the windmills, giving birth to two types of windmills that are still in use. They are:

  • Aermotor Designs
  • Dempster designs

These windmills were priced by the design Halladay windmill of 1854. The United States perceived more than six million windmills between the 18th and 19th centuries.

Definition of Windmill

How do a Windmill Work?

Windmills work on a simple principle: instead of using electricity to make wind like a fan, wind turbine use wind to make electricity. Wind turns the propeller-like blades of a turbine around a rotor, which spins a generator, which creates electricity.

Winds caused by uneven warming of the atmosphere by the sun, rotation of the earth and irregularities in the earth’s surface. Wind flow patterns vary from place to place and are altered by differences in water, vegetation and terrain.

When modern wind turbines were first built, various options were tried out. Today the universal mechanization principle consists in operating the turbine with only three blades, which are arranged around a rotor that is connected to a shaft.

Note that a number of variations have been tried, two blades and even one blade. But three blades work best.

As the name suggests, the windmill’s only source of energy is derived from the wind. The wind turns the blades, which spin a shaft, causing a generator to produce electricity.

These blades are connected to a generator, sometimes through a gearbox and sometimes directly. In both cases, the generator converts the mechanical energy into electrical energy.

Interestingly, most modern turbines rotate clockwise. Depending on the wind speed, most modern turbines can run at speeds as low as four meters per second up to 15 MP.

Quite a number of green energy advocates and non-governmental organizations describe the wind generator process more succinctly, correlating it closely with environmental sustainability initiatives.

As soon as the blades of the turbine rotate a shaft located in a box on top of the turbine, the gear mode is driven and a higher speed is output. A transformer in the turbine then converts electricity into a voltage that is suitable for distribution to a national grid.

Parts of Windmill

The following are Parts of windmill:

  • Rotor blades: The rotor blades of a wind turbine work on the same principle as airplane wings. One side of the blade is curved while the other is flat. Lifts and spins when wind blows over them, causing the rotor to turn. Most turbines have either two or three blades. The blades are “pushed” by the air to equalize the pressure differential, causing the blades to rotate.
  • Nacelle: The nacelle contains a set of gears and a generator. Sits on the tower and contains the gearbox, low and high-speed shafts, generator, steering and brake. Some nacelle is big enough for a helicopter to land on. The gears convert the relatively slow blade rotation into the generator speed of approximately 1500 rpm. The generator then converts the rotational energy from the blades into electrical energy.
  • Tower: The blades and the nacelle are mounted on a tower. It consists of steel pipe, concrete or steel mesh. Supports the construction of the turbine. As wind speed increases with altitude, turbines with taller towers can absorb more energy and generate more electricity.
  • Anemometer: Measures the wind speed and transmits wind speed data to the controller.

Types of wind turbines

There are two basic types of wind turbines based on their axis of rotation, and they are Horizontal-axis turbines and Vertical-axis turbines.

1. Vertical-axis Turbines

In the early development stage, vertical axis windmills were very popular and were in wide use. It is in such a design that the blades will be perpendicular to the ground. These vertical axis windmills replace by the horizontal axis windmills later due to their incompetence. It was mainly used for grinding grains or pumping water.

2. Horizontal-axis Turbines

The Horizontal axis windmills won many hearts due to their efficiency and productivity. It is known for its elasticity design as it harnesses more wind and easy for the operating person to change the direction according to the wind flow.

For more information check out our article: What is Wind turbine and how does it work?

Types of Windmills

There are four different types of windmills:

  • Post mill.
  • Smock mill.
  • Tower mill.
  • Fan mill.

1. Post Mill

Post windmills

The post mill is a windmill supported by a post on which it pivots to catch the wind. It is an earliest type of European windmill. Its defining feature is that the whole body of the mill that houses the machinery is mounted on a single vertical post, around which it can be turned to bring the sails into the wind.

Post mills dominated the scene in Europe until the 19th century when tower mills began to replace them

Types of post mill

There are many types of post mill.

  • Sunk post mill
  • Open trestle post mill
  • Post mill with roundhouse
  • Hollow post mill
  • Composite post mill
  • Paltrok post mill

2. Smock Mill

The smock mill is a type of windmill that consists of a sloping, horizontally weathered, thatched, or flaky tower, usually six or eight sides. It is topped with a roof or cap that rotates to bring the sails into the wind.

A smock milk is made of wood and often sits on a brick base. It differs from a post mill in that the body does not rotate, like a tower mill, it is the cap that rotates to face the wind.

3. Tower Mill

Tower windmill

A tower mill is a type of vertical windmill consisting of a brick or stone tower on which a wooden “cap” or roof sits, on which only the cap rotates to allow the sails to look into the wind.

Tower Mill is a cotton mill in Dukinfield, Greater Manchester, England. It is a listed building.

It was designed by Potts, Pickup & Dixon in 1885 and spun cotton using mules and spinning frames until ceased to be used as a cotton mill in 1955 and then used by various industries and broken down into small units according to one-point plans.

It even became decided to convert the mill into luxury apartments, but with the 2007/08 recession, this plan was abandoned.

4. Fan mill

Fan windmill

Generally, Fan mills are single-use small windmill designs. It has four to twenty blades and mainly uses to pump water.

Uses of windmill

  • Windmills are mechanical devices that use wind turbine for converting wind energy into electrical energy.
  • Windmills have been using for pumping groundwater or grinding grain.
  • Extraction of oil from the seeds.
  • Milling of the grains.
  • Processing of commodities like Tobacco, Cocoa, Dyes, Spices Paints, and Stock-watering.

Facts about Windmill

There are some interesting facts about windmills. We hope you will enjoy them.

  • Wind energy was first developed with windmills in 200 BC in Persia and China.
  • Wind energy was then used for hundreds of years to pump water and crush grain.
  • The first modern turbine was built in Vermont in the 1940s.
  • Turbine towers normally stand over 328 ft tall.
  • 20% of the energy used in Portugal and Denmark comes from windmills
  • China has the most wind turbines
  • Every second Saturday in May is celebrated as ‘National Mills Day’ in Holland
  • One megawatt of wind power can save about 2600 tons of carbon dioxide produced by fossil fuel-powered energy sources oldest windmill dates back to the eighth century and was in the Netherlands.

FAQs.

What is Windmill?

A windmill is a structure that converts wind power into rotational energy by using vanes called sails or blades, specifically to mill grain (gristmills), but the term is also extended to windpumps, wind turbines, and other applications. The term wind engine is sometimes used to describe such devices.

What are the uses of Windmill?

Uses of windmill:
1. Today, the windmill’s modern equivalent a wind turbine can use wind energy to generate electricity.
2. Windmills have been using for pumping groundwater or grinding grain.
3. Extraction of oil from the seeds.
4. Milling of the grains.

How does a windmill work?

Wind turbines work on a simple principle: instead of using electricity to make wind like a fan wind turbines use wind to make electricity. Wind turns the propeller-like blades of a turbine around a rotor, which spins a generator, which creates electricity.

Who invented windmill?

The earliest known wind-powered grain mills and water pumps were used by the Persians in A.D. 500-900 and by the Chinese in A.D. 1200. The first windmill manufactured in the United States was designed by Daniel Halladay, who began inventing windmills in 1854 in his Connecticut machine shop.

What are the Types of Windmill?

Types of Windmills:
1. Post mill.
2. Smock mill.
3. Tower mill.
4. Fan mill.

Read Also

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  5. Non-Renewable Energy | Sources, How They formed Advantages and Disadvantages.
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