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History of Windmills: Persia
- 1. Persian Vertical Axis Windmill (500AD)
- -grain was being grinded by vertical-axis windmills with woven reed sails in Persia and the Middle East.
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History of Windmills: Dutch
- 1. Dutch Horizontal Axis Windmill 1400 AD
- - sed it to drain lakes and marshes in the Rhine River Delta
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History of Wind Energy: The earliest known use of wind power
1. Arab Sailboat (2000 BC)
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History of Wind Energy: American
- 1. American steel-bladed watering pumping windmill (1860)
- -Steel blades could be made lighter and worked into more efficient shapes. They worked so well, in fact, that their high speed required a reduction (slow-down) gear to turn the standard reciprocal pumps at the required speed.
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History of Wind Energy: Polynesian
- 1. Polynesian Sailing Canoe 500 AD
- -Double canoe made of two hulls connected by lashed crossbeams.
- -Two hulls gave this craft stability and the capacity to carry heavy loads of migrating families and all their supplies and equipment
- -Central platform laid over the crossbeams provided the needed working, living, and storage space.
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The density of dry air
1.2 km m^-3 at sea level and decreases with altitude
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What is atmospheric circulation primarily driven by?
- By latitudinal temperature gradients caused by enhanced solar heating at the equator relative to the poles
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Speed: East-west winds vs. North-south winds
East-west winds are ~ 10x faster than north-south winds
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How much is absorbed solar radiation converted into wind energy?
1%
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Hadley cells
- -Closed circulation loop
- 1. Begins at the equator with warm, moist air lifted aloft in equatorial low pressure areas
- 2. to the tropopause and carried poleward. At about 30°N/S latitude, it descends in a high pressure area.
- 3.Some of the descending air travels equatorially along the surface, closing the loop of the Hadley cell and creating the Trade Winds.
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Wind patterns are stongly influence by?
Earth's rotation
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Warm air _______at the equator, rains out ______, then descends _______ latitude.
Warm air rises at the equator, rains outmoisture, then descends at ~30° latitude.
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East-West generally _______with altitude
increase
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Speed: Jet stream winds
25km/sec
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Jet stream winds are most intense during....
winter seasons
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Atmospheric Circulation Steps
- 1. Sun's radiation
- 2. Air rising and expands when it is warmed
- 3. when it cools, it descends and contracts, causing vertical motion
- 4.
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The power density of the wind: equation
1/2p v^3
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Total global wind power
- 2 Peta Watts
- -100 times human energy consumption
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A wind turbine extracts energy in proportion to its_____and its________
A wind turbine extracts energy in proportion to its area, and its coefficient of performance
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Wind turbines generally consist of.....
Wind turbines generally consist of a tower,rotors and generator
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Why do larger turbines have lower cost per watt?
- 1. Wind speeds increase with altitude (greater efficiency)
- 2. Parts count per watt (towers, blades, generators)
- 3. Energy Payback Period (EPP) is roughly independentof size, so why not go bigger!
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The largest wind turbine
Enercon E-126
7MW
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The estimated Energy Payback Period for large wind turbines...
3-9 months
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Top Global Producers of wind energy
- 1. European Union
- 2. USA
- 3.Germany
- 4. China
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Issues with Wind Power
- 1. Noise
- 2. Reliabilty
- 3. Bird safety
- 4. Human safety
- 5. Ugly factor
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Alternative Wind Power options
- 1. Giant Kite with Multi-Turbines
- 2. High way wind turbines
- 3. High altitude Tethered Air rotor system
- 4. Floating Multi-turbines
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