2010/1/29
Development of a Highly Efficient Wind
Turbine with Wind-Lens Technology
Yuji OHYA
Research Institute for Applied Mechanics
Kyushu University
Japan
Contents
Part 1. Wind Energy and Wind Turbine
Part 2. Development of a highly efficient wind
turbine with “wind
wind lens”
lens technology
Part 2A: Brimmed diffuser shroud
Part 2B: Compact brimmed diffuser shroud
Part 3. International project on Wind Energy
Utilization in China supported by NEDO
Part 4. Other projects (present and future)
Background
„
Earth environmental problem
Wind Farm
（global warming, CO2 emissions
and atmospheric pollution, etc.）
„
Energy problem
（limitation of fossil fuel）
Promotion of new energy utilization
Offshore Wind Farm
Growth of Wind Turbine Size
5MW
D=120m
Horns Rev Offshore Wind Farm
Power output increases with the swept rotor area
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2010/1/29
Installed Wind Energy Capacity
Worldwide
Goal in the future
„
„
„
„
„
Features of Wind Energy
European Wind Energy Association： Wind Force 12.
Electricity due to wind energy amounts to 12% of the
worldwide demand by 2020.
UK: Electricity due to new energy amounts to 10% of the
overall demand by 2010, 15% by 2015, 20% by 2020.
Japan： 10000MW by 2020. Electricity due to new energy
amounts to 10% of the overall demand (5% due to wind
energy)
China： 30000MW by 2020. Electricity due to new energy
amounts to 12% of the overall demand by 2020, 50% by
2050.
USA： Wind energy supplies 20% of the overall demand
electricity by 2030.
Various Wind Turbines
Merit
・Clean
Renewable
・Renewable
Classification according to rotational forces
Drawback
・Small density, dilute energy
・Intermittent and unstable nature
Classification according to structures
・Drag force type
・Lift
Lift force type
Various wind turbines（Vertical axis type）
・Vertical axis type （Drag and lift types）
・Horizontal axis ｔｙｐｅ (Lift type)
Various Wind turbines (Horizontal axis type)
Two blades
Darrieus wind turbine
Giromill type
（Lift force type）
Savonius wind turbine
（Drag force type）
Three blades
(Standard type)
One blade
Multi blades（American-style farm windmills）
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2010/1/29
Development of a highly efficient
wind turbine
Part 2
„
„
„
„
Wind Energy and Wind Turbine
Development of a highly efficient wind
turbine
bi with
i h “wind
i d lens”
l
technology
h l
International project on Wind Energy
Utilization in China supported by NEDO
Other projects (present and future)
Development of wind turbine
technology
Wind-lens turbine
ー Wind turbine system with collectionacceleration device ー
Wind-Lens Research Group
Kyushu University
Japan
For a highly efficient wind power
generating system
Wind system in Japan
Wind turbines have been developed in the following
way,
„
◎As large
g as p
possible in size
Wind stronger than 6-7m/s
is needed for wind power
generation.
H
However,
ffavorable
bl sites
it
are limited in Japan.
◎As tall as possible in height
◎Located at a site with wind as strong as possible
„
Other approaches to utilize
the low-speed (4-5m/s),
shifty winds are needed.
Annual mean wind speed (m/s)
Objectives of wind-lens research group
Wind Turbine Generation and
Wind-Lens Effect
: aiming at highly efficient utilization of wind energy
・ Development
of collection-acceleration device for
wind
・ Prediction of wind systems over complex terrain
(Numerical method with GIS and Large-EddySimulation)
・ Utilization of wind energy by the other methods :
e.g. Power generation utilizing a flutter mechanism
・ A hybrid system by utilizing wind generation
technology due to solar heating.
Wind Power P , Wind Speed V
V
P∝V3
If one can accelerate the local wind speed by capturing and
concentrating the wind with some mechanism, there appears
hope for utilizing the wind power in a more efficient way.
This concept of accelerating the wind was named the “wind
lens” technology.
Wind-Lens Effect
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2010/1/29
Part A. Development of a collectionacceleration device for wind
Concentration of wind (Increase
in wind velocity)
„
Concentration of wind
energy
gy
„
Nozzle
Wind
A structure which
shrouds a wind turbine
Nozzle type → Wind is decelerated at the entrance
Diffuser type → Wind is accelerated at the entrance
Nozzle
Diffuser
Typical configurations of
hollow-structure models
nozzle
Umax (maximum velocity) at around entrance
vs. Diffuser length
Concentration of wind
(Flow visualization)
Streamlines converge on
the entrance of a diffuser
type structure.
2
1.5
Nozzle
It means that wind is
accelerated near the entrance.
U max/U ∞
„
Diffuser
diffuser
U∞
1
1
4.6
1
1
2
1
φ
D
0.5
Φ= 4°
L
0
0
① Selection of diffuser-type
structure as the basic shroud
1
2
2.5
3
3.5
4
4.5
5
Diffuser
Development of a wind turbine with
brimmed diffuser for shorter shroud
Improvement of acceleration
performance by the addition
of periphery appendages
Brim
12m/s
1.5
L/D
The increase in wind speed from 5m/s to
12m/s at the entrance of a diffuser shroud
Velocity: 2.4 times!
Power output: 2.4x2.4x2.4=14 times ?
wind
5m/s
0.5
② Idea of a ring-type plate
which forms strong vortices
(It is called “brim”)
A collection-acceleration device for wind
(Inlet shroud + Diffuser + Brim)
Wind lens
A wind turbine with wind lens
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2010/1/29
Flow around a diffuser shroud with brim
2D-DNS, Vorticity field and streamlines
The mechanism of acceleration of
wind using a wind lens
Wind flow
Brim
Low-pressure region due
to strong vortices
Wind
flows into this region
Wind turbine
Diffuser shroud
The role of brim is to make vortices behind a shroud
Field experiment for a 500W
wind-lens wind turbine
The first prototype model of a wind
turbine with brimmed diffuser
350
Power Curve of Cw=1.4
Field Data (10min. ave.)
W.T. only
„
„
„
„
Output Powerr [W]
300
250
500W type
Rotor dia. = 0.7[m]
D=0.72[m]
L=1.25D
200
four times
increase
150
100
50
0
0
500W wind-lens wind turbine
The features of a wind turbine
with brimmed diffuser (wind lens)
Four-five times increase in output power as
compared to conventional wind turbines
„ Brim-based yaw control
„ Significant reduction in wind turbine noise
„ Improved safety
„ Improved cut-in velocity
2
4
6
Wind Speed [m/s]
8
Conventional (bare)
wind turbine
10
Break down of Tip vortices
Decrease in aerodynamic noise
Trace of tip vortices （1500rpm）:
Wind tunnel measurement
„
z=48mm
Vorticity field and Velocity vectors
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2010/1/29
Part B:
Trace of tip vortices （1500rpm）
Vorticity and Velocity vector
Development of very compact “wind lens”
(Compact brimmed diffuser shroud)
Upper: Wind-lens turbine
Problems in the application
to larger wind turbines
„
Lower: Wind turbine only
Increase in structurall weight
h
Shorter wind-lens
„
Increase in wind load
Smaller brim
Z=128mm
Z=208mm
Investigation of
„
„
Optimal sectional shape of a compact
brimmed diffuser suitable to a windlens wind turbine
Optimal combination of diffuser length
and brim height
Performance test of a prototype
compact wind-lens wind turbine
wind tunnel experiment
field experiment
CFD (numerical calculation)
1.0
Output performance with compact
brimmed diffuser length Lt/D
C0
0.8
Cⅰ
Cⅱ
Cⅲ
W.T. only
0.6
0.4
Cⅲ
0.2
Wind turbine only
Cⅱ
0.0
0.0
1.0
2.0
3.0 4.0 5.0 6.0 7.0
rω/U0 Tip speed ratio
C0
Cⅰ
Performance Curves for C-type diffusers with different length
(h=0.1D, Uo=8m/s)
Cwmax with C-type diffuser length Lt/D
If Lt/D>0.1
2-3 times as large
as a bare wind
turbine is expected
1.2
10
1.0
2.1
23
2.3
0.6
C0
0.4
with brim h=0.05D
with brim h=0.10D
with brim h=0.15D
with brim h=0.20D
W.T. only
0.2
Cⅲ
Cⅱ
Cⅰ
Development of a 1kW compact
wind-lens wind turbine
2.8 times
2.6
0.8
C w m ax
„
Power
coefficient
Cw
Z=48mm
0.0
0.0
0.1
0.2
Lt/D
0.3
0.4
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2010/1/29
Field experiment on a 1kW wind-lens
wind turbine
Diffuser shape ：Bⅲ（Lt=0.37D)
Conclusion of Part B
„
Rotor diameter：D=1.16m
Brim height
：h=0 2D
：h=0.2D
P ro d u ctio n o f electricity [W ]
600
Power Curve of Cw=1.0
Field Data (10min.ave)
W.T. only
500
400
„
300
2.8 times
200
100
0
0
2
4
6
Wind Speed [m/s]
8
10
Conventional (bare) wind
turbine
For the purpose of the practical application
to a small to a mid-size wind turbine, we
p a very
y compact
p
brimmed diffuser
developed
shroud (compact wind-lens structure).
Using this compact brimmed diffuser, we
achieved two-threefold increase in output
power as compared to conventional (bare)
wind turbines due to concentration of wind
energy.
３ｋW Wind-lens wind turbine
Part 3
„
„
„
„
NEDO* International project
Research Theme:
Development of wind-lens turbine
t h l
technology
for
f supplying
l i stable
t bl
electricity to an irrigation plant in China
•NEDO is Japan's largest public R&D management
organization for promoting the development of advanced
industrial, environmental, new energy and energy
conservation technologies.
* New Energy and Industrial Technology Development Organization
Wind Energy and Wind Turbine
Development of a highly efficient wind
turbine with “wind lens” technology
International project on Wind Energy
Utilization in China supported by NEDO
Other projects (present and future)
NEDO project (2006-2007)
„
Research group:
Collaboration between Japan and China
Japan
Kyushu University
Torishima Co., Ltd., Yaskawa Electric Co., Ltd Group
China
Gansu Natural Energy Research Institute
（United Nations Industrial Development
Organization (UNIDO)
Tsinghua University
Institute of Nuclear and New Energy Technology
Supported by NEDO, Japan
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2010/1/29
Desert damage of 77 billion US $ over the
world
Content of the project
Desertification has been extending over 1/4 land
in China
Utilization of wind energy by using
highly efficient wind-lens
highly-efficient
wind lens turbines
„ Pumping underground water
„ Planting trees in a desert area in
Gansu, China
„
Schematic of the present project
Wind turbine
water tank
pump battery
Underground water
Image of irrigation using wind energy
5ｋW Wind-Lens Turbine (Field Test)
（Rated Wind Speed 12m/s、Rotor dia. of 2.5m）
Field Data (1min. average)
Cw=1.0 （Wind-lens Turbine）
2,500
Wind-lens
turbine
For the electricity demand of an irrigation plant,
the power output of the wind farm using 1kW
wind-lens turbine is short.
6 sets of 5kW turbines have
been installed in a desert area.
Rotor dia. 2.5m
Desert in North-west in China, Gansu
Province (Irrigation plant using 5kW wind-lens
turbines)
Desert of 10,000m2（１ｈａ)
2.5 times
i
increase
C 04 (C
Cw=0.4
(Conventional
i l Wind
Wi d T
Turbine）
bi ）
2,000
Development of 5kW Wind-Lens
Turbine
Water of 20m3/day is provided
automatically
3,500
3,000
Gansu
Province
Therefore, we have developed
a 5kW wind-lens turbine.
desert
W
China
1,500
1,000
500
Conventional
Wind Turbine
0
0.0
2.0
4.0
6.0
8.0
10.0
12.0
m/s
5kW Wind-Lens Turbines for
Irrigation in a Desert Area in
China
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2010/1/29
Other Projects
Part 4
„
„
„
„
Wind Energy and Wind Turbine
Development of a highly efficient wind
turbine with “wind
wind lens
lens” technology
International project on Wind Energy
Utilization in China supported by NEDO
Other projects (present and future)
Small Wind-lens turbine (5kW)
Adaptable to the
surroundings
Power [kWh/yeaar]
Annual Electric-Generating Capacity
20,000
18,000
16,000
14,000
12,000
10,000
8,000
6,000
4,000
2,000
0
Small wind-lens turbine project
„ Wind energy utilization in a city which
faces the sea
„ The utilization of wind above the roof of
a building
Project on larger wind-lens turbines
„ 100kW mid-size wind-lens turbine
„ Offshore wind farm using wind-lens
turbines in the near future
Micro-siting of wind-lens turbines in Fukuoka city
which faces the sea using Riam-Compact (LES)
Hakata bay
Fukuoka city
Windlens
turbines
• Faces the sea
in the north
• Has a long
seashore
which is
suitable for
wind energy
utilization
16,825
13 323
13,323
9,530
5,955
3,133
393
2.0
1,325
3.0
4.0
5.0
6.0
7.0
8.0
Average Annual Wind Speed [m/s]
Rotor dia. of 2.5m
Calculation domain and parameters by using
Riam-Compact based on Large-Eddy-Simulation
wind
CFD with turbulence
model and GIS
Velocity vectors at a height of 15m above the
ground
0.9
Wind
u/Uref
Uref=1
at z=h
-0.2
○North wind
○Inlet Condition: 1/7
power law (Atmos.
Boundary Layer)
○Grid：161×201×51
○∆x=∆y=17.5m
Numerical Modeling by rectangle
bodies for buildings and houses
○∆zmin=1m
○Re=10,000 (based
Wind speed increase
iin th
the entrance
t
off a
river
Decreasing speed in
the upstream of tall
buildings
○The results shows
the wind converging
effects toward a river
on h)
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2010/1/29
Installation of wind measurement pole
Fukuoka city
Hakata bay
Pole
Minato
100
years
park
Windlens
turbines
Windlens
turbines
2009.
12.7
５ｋW Windlens
turbines in seashore
Momochi-hama park
2009.12.7
EV Project in Ito Campus, KU ２００９
On the roof of a building
５ｋW Windlens turbine
Electricity
charger
Mid-size Windlens Turbine（100kW） : Next
Generation Energy Project at Ito Campus , KU
2/3 rotor diameter size
Quiet
100kW
Rotor dia.
of 13m
Installation
site
5kW
Windlens
turbine
Wind Tunnel Exp. for New Windlens
Turbine of 100kW Size Model
Type1(10%brim）
W
100kW Windlens
T bi Model
Turbine
M d l
Type2
(5%brim)
Two times
increase
Rotor dia.
of 2.5m
m/s
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2010/1/29
Off Shore Windlens Turbine（100kW） C.G.
Huge floating
body
Future Plan :
Offshore Wind-Lens Turbine (CG)
Semisubmarine
By Prof.
Kyozuka
10MW、Rotor dia. of 112m、2 times output power compared
with conventional wind turbine
New structural material
is expected as like 2nd generation CFRP
Offshore Wind Farm (CG)
Floating body type
Thank you for your kind attention !
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