Waterwheels, used since ancient times as a source of mechanical energy, for example to move the millstones, originally were built as Horizontal wheels with a vertical axis: these wheels are generally known as “Greek” or “Scandinavian”
The horizontal wheel, which is probably the primordial form of the waterwheel, is able to generate a limited power: it is mounted inside a mill, below the work surface, and it is powered by a jet of water which requires a boost of approximately 10 m.of a directly jump towards the paddles of the wheel that in this way rotates.
It is a simple system, usually with no gears, and is structured so that the vertical axis of the wheel will become the drive spindle of the millstone
In the first century BC a Roman engineer, Vitruvius, conceived the first idea of a vertical waterwheel, adding a couple of gears to the then existing mill “Greek”: thus was created the “Vitruvian” mill
In force of to this innovation we had a wheel with a better returns and with improved technological knowledge; this type of mill had completely supplanted the mill with horizontal wheel
Such a wheel is being worked excellently both with a minimum fall of water both with large flows, thus generating, in this last case, more strength: with only one wheel were driven more millstones, become more and more necessary due to the demographic growth
These wheels are classified, according to the way in which water is applied to the axis, in:
- Overshot Wheels that are suitable where there is a small stream, with a drop of 2 meters, often in association with a small basin.
- Breastshot and Undershot Wheels that can be used on rivers or large basins with high flow
The advent and the rapid expansion of fossil fuels has almost totally cast aside their use
Currently, however, global warming caused by the use of these fuels has led us to a greater respect for the environment and toward the use of alternative energies.
For this reason the waterwheels are increasingly being used to produce simple and clean energy through the transformation of mechanical energy into electrical energy produced by them, by coupling to wheel an appropriate generator power.