Transcript urban_wind_conditions.pptx

Steep changes in terrain,
such as tall buildings
cause turbulence in the air flow
on both the base and the top
of the structure,
which results in power loss.
To avoid turbulent flows, we
must place the turbines in
respect to this figure,
which shows the
Zone of maximum turbulent
flow:
The distance between the wind
turbine and the obstacle
causing the turbulance (10H+),
must be at least 10 times larger
than the height of the obstacle.
Of course as if in open land, it is better to put the wind
turbines on a greater height, but it is also important to
put them at least 10 meter above the highest point of
the roof and also other obstacles and buildings within
a 100 meters.
These rules are
hard to keep up
with, in a costeffective
perspective.
• We used two anemometers.
(AIRX, UNITEK)
• Our reference point was the
location marked by AIRX arrow.
• We did measurements in two
week cycles on locations 1-4.
During the reference measurements, it turned
out that the UNITEK instrument measures only
80% of the wind velocity of what the other
device was showing, so we had to correct the
values according to this difference.
In the city environment, streets act like channels for
the wind, as shown on the picture above.
It’s important to be aware of these wind-maps in
order to maximize efficiency trough proper turbine
placement.