a ppt by varun tripathi

8/12/2019 A Ppt by Varun Tripathi

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A PPT ON

HYDROELECTRICAL

GENERATION

BYVARUN TRIPATHISUMMITED TO- HOD MECH.


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Hydroelectrical Power Generation

Traditional Methods of Hydroelectric Generation

Low Head Power Generation

Medium Head Power Generation

High Head Power Generation

Large Dams (Three Gorges, Itaipu)

Environmental Effects of Large Dams


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Energy in the News


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Breast Shot Wheel

Breast shot wheel:

One type of traditional

Water wheel

Water wheels: sourceOf power for the

Industrial revolution


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Overshot Wheel

More efficient that breast shot

Wheel. Some mills using

These wheels still in operation

In rural appalachia in 1950s

Miller: Mrs. Aarendale


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Typical Hydroelectrical Station

Outflow water: can be very cold. Why? (Grand Canyon)


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Low Head Hydroelectrical Generators

Low head:Propellor type

Turbines

Power =Change in Potential

Energy per Unit tim

= weight*

Vertical drop/time

Energy =

Power*time


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Microhydro Installation

Small stream with

Hydroelectrical generator:

Power for one family

(Jim Keener)


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Moderate Head Hydro

Head: height difference

Between water level in

Reservoir and water

Level entering turbine

Head= height in potential

Energy equation

Penstock: tube water flows

Through


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Francis turbine

Turbine used for moderate

Head hydroelectrical power

statiosn


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Water Flow in a Francis Turbine

Left: relative to turbine blades Right: true water path


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High Head Hydro


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Pelton Water Wheel

Used for high head applications:(above 250 meters)

Are impulse turbines.

Francis and Propeller type turbineAre reaction turbines.

Reaction turbines: run submerged.

Impulse turbines: run in normal air


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Jets of Water Hitting Pelton Wheel

Jets of water are directed through a nozzle onto Pelton wheelCups on the wheel transfer kinetic energy from water to wheel.


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Optimum Hydroelectric Turbine Type

Optimum water

Wheel: not

Just a function

Of head, also

Depends on

Water flow rate


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Hydroelectrical Power Use by State


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States Producing Most Hydroelectricity

Why is there

So much

Variation in the

Gallons of water

Per kilowatthour?


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Hydropower Output by Nation

Lure ofHydropower

Big Dams

Vs

Rebar


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Three Gorges Area of Yangtze River

Under

construction

Three Gorges

Dam in China

Moving 1.2 million

People

Capacity of18,600 MW

Will finish in 2009


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Three Gorges Area

Great beauty

Many historic

Sights

Still pressing

Ahead on dam

construction

Gorge length;

~San Francisco

To LA


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Environmental Problems with Dams

1) Silt buildup fills reservoir (Yangtze; levees)

2) Fish migration disrupted (Columbia)

3)Water temperature decreases (Colorado)

4) Water gets more saline (Colorado)

5) Water loses oxygen (Brazil)6) Water slows down, increases disease

(mosquitos, schitosomiasis (Aswan))

7) Water traps pollution, slows pollution flushing

8) Induced seismicity may occur

a ppt by varun tripathi

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