A SEMINAR ON UNDER WATER WINDMILL Presented by: Rajesh Kumar Sahu Regd No:090101MER020 Mechanical Engineering

CONTENTS Introduction Main parts Working principle Types Advantages Disadvantages Global resources Conclusion References

INTRODUCTION What is it ??? An Underwater windmill like a device that extracts power from the tides. Renewable energy technologies are becoming an increasingly favourable alternative to conventional energy sources to assuage fossil fuel related issues. Tidal energy offers a vast and reliable energy source. This technology is similar to wind energy technology, with the rotor blades driven not by wind power but by tidal currents. The gravitational pull of the moon produces a swift tidal current, which spins the long blades of the turbine . Which in turn produces electricity via different parts of underwater windmill . This Energy derived from the moon that now helps to power a small arctic village.

NAME JUSTIFICATION Why it is called as “underwater windmill” ? "Basically it's like putting a windmill in the water," said Bjorn Bekken, a project manager for Hammerfest Strom. Or as it’s looking like a wind mill & are installed on the ocean floor and large river bed , that means these are under the water.

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MAIN PARTS Turbines Gearbox Generator Cables support

PRINCIPLE OF OPERATION In simple a underwater windmill consists of a number of blades mounted on a hub (together known as the rotor), a gearbox, and a generator. The hydrodynamic effect of the flowing water past the blades causes the rotor to rotate, thus turning the generator to which the rotor is connected via a gearbox. The gearbox is used to convert the rotational speed of the rotor shaft to the desired output speed of the generator shaft. The electricity generated is transmitted to land through cables.

TYPES : There are two types of underwater windmill Horizontal axis Vertical axis In horizontal axis underwater windmill , the rotor shaft is parallel to the direction of the flow of water. In vertical axis underwater windmill , the rotor shaft is perpendicular to the direction of the flow of water.

ABOUT TURBINES… The turbines can convert kinetic hydro energy into power ranging from 25 kW to 250 kW, depending on turbine size and current. Kinetic energy is converted to mechanical power in a nacelle within the turbine.

WORKING… Underwater ( tidal) turbines are a fairly straightforward concept, as far as cutting-edge energy technology goes. They are essentially windmills installed onto an ocean floor or river bed. The underwater current produced by the tides spins blades arranged like an airplane propeller. These turbines are attached to a gear box, which is connected to an electrical generator. This produces the electricity that is carried by cable to shore. Once it's plugged into an electrical grid, the electricity can be distributed.

SPECIALIZATION How it is special from others like, 1.Watermill 2.Windmill Lets Know………

WATERMILL A watermill is a structure that uses a water wheel or turbine to drive a mechanical process such as flour, lumber or textile production, or metal shaping (rolling, grinding or wire drawing). There are two basic types of watermill, one powered by a vertical waterwheel via a gearing mechanism, and the other equipped with a horizontal waterwheel without such a mechanism. The former type can be further divided, depending on where the water hits the wheel paddles, into undershot, overshot, breastshot and reverse shot waterwheel mills.

View: Watermill of Braine-le-Château, Belgium (12th century)

CONCEPTICAL DIAGRAMS Undershot water wheel, applied for watermilling since the 1st century BC Overshot water wheel, applied for watermilling since the 1st century BC Breastshot water wheel, applied for watermilling since the 3rd century AD

WIND MILL

ADVANTAGES: The advantages of under water windmill is much more than the disadvantages:- Uses Tidal energy ,which is a clean and renewable source of energy Have lesser impact on the environment Low running cost Long lifetime with little maintenance Reduces the dependence upon fossil fuels where annual operation and maintenance costs are typically less than 0.5% of initial capital cost of the scheme.

DISADVANTAGES: The initial cost is too high Very difficult to install The blade must be coated to avoid corrosion Special type material must have to be used for blade These devices must be designed for ease and speed of installation. Construction of foundations and installation during tidal currents will be challenging, with only a few minutes of slack time between tides.

GLOBAL RESOURCES It is widely agreed that, tidal stream energy capacity could exceed 120GW globally . The UK has one of the largest marine energy resources in the world.

CONCLUSION Tides play a very important role in the formation of global climate as well as the ecosystems for ocean habitants. At the same time, tides are a substantial potential source of clean renewable energy for future human generations. Depleting oil reserves, the emission of greenhouse gases by burning coal, oil and other fossil fuels, as well as the accumulation of nuclear waste from nuclear reactors will inevitably force people to replace most of our traditional energy sources with renewable energy in the future . Tidal energy is one of the best candidates for this approaching revolution. Development of new, efficient, low-cost and environmentally friendly hydraulic energy converters suited to free-flow waters. This type of machine, moreover ,can be used not only for multi-megawatt tidal power farms but also for mini-power stations with turbines generating a few kilowatts. Such power stations can provide clean energy to small communities or even individual households located near continental shorelines, straits or on remote islands with strong tidal currents.

REFERENCES http://www.marineturbines.com/ http://www.renewable-solarenergy.com/tidal-energy-power.html International Energy Agency, World Energy Outlook 2007. Prandle, D., Simple theory for designing tidal power schemes, Advances in Water Resources, 1984. Sheth, S. and M. Shahidehpour, Tidal Energy in Electric Power Systems, in Power Engineering Society General Meeting, 2005. http://www.tidalenergyltd.com/technology.htm

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