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A water wheel is a machine for converting the kinetic energy of flowing or falling water into useful forms of power, often in a watermill. A water wheel consists of a large wheel (usually constructed from wood or metal), with numerous blades or buckets attached to the outer rim forming the drive mechanism. Water wheels were still in commercial ...
Old Pelton wheel from Walchensee Hydroelectric Power Station, Germany. The Pelton wheel or Pelton Turbine is an impulse-type water turbine invented by American inventor Lester Allan Pelton in the 1870s. [1] [2] The Pelton wheel extracts energy from the impulse of moving water, as opposed to water's dead weight like the traditional overshot ...
Some hydropower systems such as water wheels can draw power from the flow of a body of water without necessarily changing its height. In this case, the available power is the kinetic energy of the flowing water. Over-shot water wheels can efficiently capture both types of energy. [7] The flow in a stream can vary widely from season to season.
Watermill of Braine-le-Château, Belgium (12th century) Interior of the Lyme Regis watermill, UK (14th century). A watermill or water mill is a mill that uses hydropower.It is a structure that uses a water wheel or water turbine to drive a mechanical process such as milling (grinding), rolling, or hammering.
The main difference between early water turbines and water wheels is a swirl component of the water which passes energy to a spinning rotor. This additional component of motion allowed the turbine to be smaller than a water wheel of the same power. They could process more water by spinning faster and could harness much greater heads.
Francis type units cover a head range from 40 to 600 m (130 to 2,000 ft), and their connected generator output power varies from just a few kilowatts up to 1000 MW. Large Francis turbines are individually designed for each site to operate with the given water flow and water head at the highest possible efficiency, typically over 90% (to 99% [6]).
Typical efficiency of water wheels exploiting only the kinetic energy was around 30%. [1] These wheels are called stream water wheels, or kinetic water wheels. Instead, undershot water wheels are used in low head sites, like less than 1.5 m, and they also exploit the potential energy of the flow, with efficiencies of up to 84%.
Overshot water wheel maximum efficiency (hydraulic efficiency) is 85%. [12] [13] Undershot water wheels can operate with very low head, but also have efficiencies below 30%. [14] Gravitation water vortex power plant : part of the river flow at a weir or natural water fall is diverted into a round basin with a central bottom exit that creates a ...