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28 Cards in this Set
- Front
- Back
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T/F a wind turbine has a large physical footprint relative to the amount of electricity it can produce
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false
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where are many wind projects located?
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farm, grazing, and forest land
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What are two benefits of wind energy?
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clean
cost competitive |
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What are some drawbacks to wind energy?
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Large
Visual impacts Noise Flicker Birds Maintenance Materials intensive |
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Which continent has really developed win energy?
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Europe
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What are the sources of the wind?
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(1) Non-uniform heating of the Earth surface by the sun
(2) Rotation of the Earth |
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Define: Wind Turbine
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devices that convert the kinetic energy of wind into the mechanical energy of rotating blades
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What is the power train of wind energy?
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wind+wind turbine+generator=electricity
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What are more efficient, multi or single blade rotors?
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single
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The Power delivered by a wind turbine, is proportional to…
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Air density
Swept Diameter Blade, i.e. square of the blade diameter Cube of Wind Velocity |
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The Power delivered by a wind turbine, is proportional to…
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Air density
Swept Diameter Blade, i.e. square of the blade diameter Cube of Wind Velocity |
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The relationship between power rating and rotor diameter is direct/inverse
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direct
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Windmills traditionally used for pumping water have small, solid rotors with many blades. What is the main advantage of these designs?
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The many blades assure operation at very slow wind speeds, allowing continuous operation all year.
These windmills are, however, very inefficient at high speeds and must be shut down to prevent damage. |
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What are some safety and control concerns for wind turbines?
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Vibration
High wind speed Shut-off control mechanism Noise (Mechanical + Aerodynamic) Temperature Air or Water cooling system Speed Pitch and Yaw(Tilt) controller Stall Regulation |
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What are some current solar energy applications?
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heating swimming pools
heating water for domestic use space heating of buildings |
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The amount and intensity of solar energy available vary depending on
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Geographical location,
Position of the sun in the sky, Weather conditions, and Orientation of the collector and surrounding objects. |
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What does the sun mostly consist of
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hydrogen and helium
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define altitude in terms of solar position
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angle between the sun and the horizon.
Zero at sunrise and sunset Maximum at noon |
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define zemith angle
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the complement of solar altitude angle, or the angle of the sun from a vertical line directly overhead.
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defineL azimuth
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angle between a north-south line on the Earth’s surface and the horizontal projection of the sun’s rays;
negative before noon, and positive after noon. |
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define: solar insolation
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Solar Insolation the amount of radiation arriving from the sun that collides with a flat surface.
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sun rises higher in the sky in the winter/summer
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summer
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Where are the most favorable places of solar radiation
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covering land masses of many developing countries of Northern Africa and Southern Asia. They receive, on average, 3,000 hours of mostly direct sunshine and limited cloud coverage.
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Fill in the blanks
1m2 of collecter area receives _________ of sunshine and procudes ____ of electricity |
kilowatt
100 w |
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Today , only ___ of global electricity is solar-powered
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1%
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What is passive solar heating
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Collection of solar energy without the use of electrical or mechanical power.
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What are two methods of active solar heating?
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flat-plate collectors
evacuated tube collectors |
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What are some methods of passive cooling
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reduce the losses by keeping heat out
insulate the walls, making walls thicker reduce surface area of south-facing windows plugging all the leaks |
