Design a model of OWC plant for Sri
-
Upload
pathishe73 -
Category
Documents
-
view
23 -
download
4
Transcript of Design a model of OWC plant for Sri
Sea wave powered power plant for Sri
Lanka and some aspects of modeling
Presented ByA.M.P. Jayamanne
Why sea wave power for Sri Lanka ?
Sri Lanka has huge potential of wave power
Small frequency variations
Plenty of sites
Can use as a break water
Less environmental impact
Medium rough sea conditions
The technic and why?Propose Oscillating Water Column (OWC)
wave extractor.Promising and proven technology
Simple structure
Less links from wave to turbine which causes the loses minimum
Total concrete collector
An OWC plant…Turbine
ChamberOscillating
water columnIncoming
Water waves
Available Plant..
The 400 kW Oceanlinx wave powered generator off the coast at Port Kembla NSW Australia
Wells - TurbineUse wells turbines because it generates torque in one direction even air flow is bidirectional.A low pressure air turbine
Hub
Generator
Rotor
Stator
Pilot valve
Wave dinamicsPartial Moving
path
Water surface
Sallow water
Zero Crossing
time
Wave height
Deep water
Total energy (P)= Kinetic energy + potential energy
P = [ρg2 /64π]*H2 T ≈ 0.5 H2 T (kw/m)
H = significant wave height = 4* standard deviation of water surface elevation
T = Zero crossing wave time period
Sri Lankan wave potential..
1 2 3 4 5 6
0
20
40
60
80
Bundala
Month
PK
W/m
)
1 2 3 4 5 6 7 8 9 10 11 12
0
2
4
6
8
10
12
14
16
Dodandoova
Month
P k
W/m
1 2 3 4 5 6 7 8 9 10 11 12
020406080
100
Godayaya
Month
P (
kW/m
)
1 2 3 4 5 6
0
20
40
60
80
100
Palatupana
Month
P(K
W/m
)
Best Site – GodayayaMean significant wave height
–2.8mZero crossing time – 11.05 -
13.34Mean zero crossing time –
12.23
Mathematical model
Air way
Added damping/turbin
e
Applied damper/friction
Floating water mass
Wave force
Wave entrance
Buoyancy spring
Applied spring/viscosity
Displacement
Collector
Model Equation.. Applied wave force due to the traveling of wave in to the cession =
F e(t).
Water column displacement for an instant time = y Instant time = t Applied damping coefficient due to friction = f
Applied damping coefficient due to turbine = t
Added water mass = m a
Floating water mss = m f
Applied spring coefficient due to water mass = ks
Buoyancy spring coefficient = kb
d = 1/2( ma + mf ) x [(4 ma2 g2 - t
2) / 4 ] ½
( ma + mf ) d2y/dt2 + t dy/dt + kb y = F e(t).
Modeling..Procedure
Match actual frequency to model frequency and wave forcers
Compare available plants for Sri Lankan conditions Select best plant Scale it to model willing to build Structural and turbine design.
Results
Best plant – NEL ( Developed by Lanchester University and Polytechnic)
Scale Factor - 9.5
Collector..
Turbine..
Conclution of OWC plant performance..
Wells turbines have low efficient ratesEffective energy can captured from waves
to generator is around 12%Reduces performance due to high
frequency changersCollector profile or volume has to change
due to incoming wave frequency and amplitude changers
Sri Lankan wave climates are giving positive behavior to OWC plants.
Need to do more involvement to success
Thank You