Agriculture Reference
In-Depth Information
Example 13.5
Determine the potentials of electricity generation fromwind energy per wind turbine
having average wind speed 15 km/h, 3 blades, radius of the blades 2 m, turbine
efficiency of 60%, and generator efficiency of 85%.
Solution
We get,
P
w
=
r
2
V
3
E
T
E
G
/
ρ
π
1
2
n
Given,
V
=
15 km/h
=
4.1667 m/s
n
=
3
r
2m
E
T
= 60%; = 0.60
E
G
= 85% = 0.85
Assuming air density,
=
1.2 kg/m
3
ρ
=
Putting the values,
P
w
=
834.4855 W (Ans.)
Example 13.6
Determine the increase in electricity production from wind energy in an area if the
wind speed increases from 10 to 20 km/h.
Solution
AV
3
E
T
E
G
Here, all but 'wind speed' are constant, thus we can write,
P
w
=
We get,
P
w
=
1
/
2
ρ
CV
3
Given,
V
1
=
=
10 km/h
2.778 m/s
V
2
=
=
5.556 m/s
For 1st speed, power,
P
w
−
1
=
20 km/h
C
(2.778)
3
=
×
C
21.43W
C
(5.556)
3
For 2nd speed, power,
P
w
−
2
=
=
C
×
171.47W
P
w
−
2
−
P
w
−
1
=
C
(171.47
−
21.43)
=
C
×
150.03W
%increase in power
=
(
C
×
150.03
×
100
/
(
C
×
21.43)
=
700.0 (Ans.)
13.6 Water Energy
Energy in water (in the form of motive energy or temperature differences) can be
harnessed and used. Since water is about 800 times denser than air, even a slow
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