Small wind machines
Wind Energy
!!!!!!!!!"
#
#
!
$
%
&
!!
#
'
(
)
*
+
#
#
( "
%#
"
#
$
#
*(
,
WIND
-
.
WIND
TURBINE
SUB – SYSTEM
CONTROL
SYSTEM
CONTROL
ELECTRICAL
GENERATOR
POWER
CONDITIONING
ELECTRIC
DISTRIBUTION
STORAGE
BATTERIES
UTILIZATION
Figure 1 Schematic diagram of wind electric system
#
"
'
#
#
"
/
"
%
#
/ "
#
#
#
#
0
#
#
#
Wind resource assessment
'
#
$
# 1
#
#
# 1
# 1
#
#
#
#
0
% #
2!&
34
#
#
2!&
3 4! 5
!!&
5
3 46 5
# #
Wind resource evaluation is a critical element in projecting
turbine performance at a given site. The energy available in a
wind stream is proportional to the cube of its speed, which
means that doubling the wind speed increases the available
energy by a factor of eight.
Table 1 Classes of wind power density at 10 m and 50 m(a)
Wind
10 m (33 ft)
50 m (164 ft)
power
Wind power
Speed(b)
class
density (W/m2)
m/s (mph)
Wind power density
Speed(b)
(W/m2)
m/s (mph)
1
<100
<4.4 (9.8)
<200
<5.6 (12.5)
2
100 - 150
4.4 (9.8)/5.1 (11.5)
200 - 300
5.6 (12.5)/6.4 (14.3)
3
150 - 200
5.1 (11.5)/5.6 (12.5)
300 - 400
6.4 (14.3)/7.0 (15.7)
4
200 - 250
5.6 (12.5)/6.0 (13.4)
400 - 500
7.0 (15.7)/7.5 (16.8)
5
250 - 300
6.0 (13.4)/6.4 (14.3)
500 - 600
7.5 (16.8)/8.0 (17.9)
6
300 - 400
6.4 (14.3)/7.0 (15.7)
600 - 800
8.0 (17.9)/8.8 (19.7)
7
>400
>7.0 (15.7)
>800
>8.8 (19.7)
(a)height
above the ground level
Mean wind speed is based on Rayleigh speed distribution of equivalent mean wind
power density.
(b)
0
. #
*
#
#
/
##
5 /7 #
(
#
#
'
#
.
2 5
(
/
##
'
#
#
%
+
#
# (
'
#
#
#
Figure 2 Effect of strong winds on area vegetation (this can help
determine area wind speed)
#
#
"
8
9
#
Wind speed to operate a turbine
The greater the wind speed the better. Most small/micro wind
turbines start to generate electricity in wind speeds of
approximately 3-4 meters per second and reach their
maximum output at a wind speed of 10-12 meters per second.
$
#
#
(
"
$
%
#
#
!
!!
Figure 3 A Typical wind rose for wind resource assessment
Site selection criteria
#
#
# #
0
#
:
/
#
%#
"
#
# #
#
#
/
#
;
#
#
"
#
7
!!
#
/
/
#
!
7
#
!
"
"
"
"
$%
#
"
Wind power calculations
(
<
#
#
#
#
#
#
#
# #
#
#
#
# #
#
/
#
The power of wind
=
1
"
>
(
?
4!2× =
)
×3
"
5
1
"
=
5
"5 43
@
!
!
#
# "
(
<
%+
5 %
#
"5
"
#
#
#
"
(
>
(
.
'
4!2× - #
.
(
3
×
'
+
1
#
)A4 6 + 3
'
>
)A4
+4B
34
#
#
"' 5
#
#
*
5
"
'
- #
#
1
#
#
1
×3
5
"
.
6
4
/
#
π×
!
"
"
! #
2='
>
4!2×
!×
#
×
"5
5
×
×
!!!!!!'
#
Wind turbine(s)
'
"
$
#
')C
=
D
/ %
# #
/
+
=
#
$
#<
"
/ %
"
0
D
/ %
Figure 4 Various components of horizontal-axis wind turbine (HAWT)
@ '
#
#
# #
#
"
-
#
=
#
#
%
( "
3'
=
5
%
#
*
##
*
"
#
#
(
#
$
/ %
#
%
Figure 5 Various components of Vertical-axis wind turbine (VAWT)
#
D
%
#
#
>
<
%
##
A
( #
##
<
( #
( #
Small wind electric system
'
#
!!"'
#
$
#
#
=
D
2(
## %
D
2!"' 6
## %
#
'
#
#
#
2"'
'
!! (
Basic parts of small wind electric system
@
#
#
5
#
#
"
Figure 6 Basic parts of a small wind electric system
Wind turbine
D
%
=
#
/
#
/ #%
Tower
'
#
$
#
#
%
!
7!
!!
Balance of system
(
#
/
/
0
/
#
#
Stand-alone systems
/
(
%
#
#
##
7
" #
$
# #
+C
##
+C
#
Figure 7 Schematic of a gridconnected wind electric system
Grid-connected systems
$
(
/
( #
#
#
"
#
0
#
C
#
#
−
#
−
##
E
:
!!!'
"'
E
"'
"'
−
-
##
F
$
B
=
E
2!"'
system
Windmill pumps
#
#
#
#
#
#
#
#
#
#
E %
#
#
#
%#
#
#
/
2
#
#
#
2!
#
# #
!G
#
# #
+
#
!!2
$
Figure 8 Time variation of the cumulative number of windmill pumps in india
F
#
#
#
#
#
#
#
#
Estimated water
Designs/ models
Broad technical specificans
output vs head
Suitability
Direct drive windmill such
Rotor dia – 5 m
8000 liters per hour
For shallow water pumping
as 12 PU 500 and similar
No. of blades – 12
at 7 meter head
upto 15 meter head
other windmills
Tower height – 7 m
Rotor dia – 3.3 m
4000 liters per hour
For shallow and deepwell
No. of blades – 18
at 15 meter head
pumping upto 60 meter head
AV 55 Auroville direct drive Rotor dia – 5.7 m
4000 liters per hour
For shallow and deepwell
windmills
at 15 meter head
pumping upto 60 meter head
Pump dia – 150 mm
Cut in wind speed – 10 kmph
Rated wind speed – 18 kmph
Gear type windmills
Tower height – 10 m
Pump dia – 50-100 mm
Cut in wind speed – 9 kmph
Rated wind speed – 18 kmph
No. of blades – 24
Tower height – 9-23 m
Pump dia – 64-160 mm
Cut in wind speed – 10 kmph
Rated wind speed – 18 kmph
Figure 9 Schematic diagram of a typical wing mill
Figure 10 Various components of a wing mill