Poor Mountain Wind Analysis
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Transcript of Poor Mountain Wind Analysis
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Creating a venue for a
Wind Analysis Study for a site on
Poor Mountain in Roanoke County, Virginia
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This image describes a 650 ft x 650 ft pixel size
overlay of a Wind Density Analysis extrapolated
from data from sites, nationwide, on a vertical
elevation above sea level basis to assess electrical
energy production for a site on Poor Mountain in
Roanoke County, VA
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Understanding the
Wind Developers
Wind Analysis Study
for a site on
Poor Mountain in
Roanoke County,
Virginia
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Is this site on
Poor Mountain in
Roanoke County,Virginia a key
to accessing
additional energy
resources from the
abundant wind power
bands near a little
model city in the
southern Appalachians?
http://upload.wikimedia.org/wikipedia/commons/9/96/Diagrama_de_formacion_de_la_brisa-breeze.png -
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A: Sea breeze (occurs at daytime)
B: Land breeze (occurs at night)
Mountain wave schematic. Th
towards a mountain and prod
oscillation (A). A second wave
away and higher. The lenticula
the peak of the waves
http://upload.wikimedia.org/wikipedia/commons/9/96/Diagrama_de_formacion_de_la_brisa-breeze.png -
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Wind Flow Visualization over Appalachian Mountain Terrain
Poor Mountain Wind Reaping - Roanoke County - Virginia
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The wind profile power law relationship is:
u/ur = (z/zr)
where u is the wind speed (in meters per second) at height z (in m
known wind speed at a reference height zr. The exponent () is an
coefficient that varies dependent upon the stability of the atmosp
stability conditions, is approximately 1/7, or 0.143.In order to estimate the wind speed at a certain heightx, the rela
rearranged to:
ux = ur(zx/zr)
The value of 1/7 for is commonly assumed to be constant in win
assessments, because the differences between the two levels are
as to introduce substantial errors into the estimates (usually < 50
a constant exponent is used, it does not account for the roughnes
displacement of calm winds from the surface due to the presencezero-plane displacement), or the stability of the atmosphere. In p
structures impede the near-surface wind, the use of a constant 1/
yield quite erroneous estimates, and the log wind profile is prefer
neutral stability conditions, an exponent of 0.11 is more appropria
(e.g., for offshore wind farms), than 0.143, which is more applica
surfaces.
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Rayleigh Distribution - Wind Speed
The purpose of this page is to illustrate the use of the Rayleigh distribution to
energy recovered by a medium sized wind turbine. The parameters are illust
important to obtain site specific parameters for a project evaluation.
Basic Equation
The equation for energy recovery from the wind is as follows:
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Coefficient of Performance
Not all the energy can be recovered from a
wind stream. The theoretical maximum value
for the coefficient of performance is 0.593. An
"ideal" wind turbine with this maximum value
is known as a Rayleigh-Betz machine.In practice the value of the maximum values of
coefficient is in the range 0.25 to 0.45.
In general, the larger the machine the higher
the value. Also the use of variable pitch rotors
can optimize the coefficient of performance
for a range of wind speeds. The curve used in
the example is shown below.
The maximum value of the coefficient has
been set close to the modal wind speed for
Rayleigh averages in the range 5 - 7 m/sec. The
rotor design should be optimized for the site.
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11/15From GE Wind (2.5xl Power curve speculation NOT fro
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Poor Mountain PThe Nature Conse
Globally Rare PiratBottom CreekHeadwaters
Big Laurel Creek
Headwaters
Bottom Creek Gorge
PreserveThe Nature Conservancy
EPA/DEQ Tier III Stream