Wave Dragon

Wave
Power
by Jan Müßener
Content
• Introduction
• Three different kinds of wave power stations:
1. WaveGen
2. Pelamis
3. Wave Dragon
• Overview / State of completion
• Sources
Introduction
• advantages of wave power:
• required place to generate 1kW:
solar collector: 10 m2
wind turbine: 2 m2
wave power: 1 m2
• relative constant power-output level
• about 15% of the worldwide energy demand could be
supplied
• but efficiency is very depending on the location
Introduction
power-density of waves around the globe (in power per length of wave [kW/m] )
• powerful but irregular waves in the north and the south
• weak but absolutely equal waves near the equator
WaveGen
• “Limpet” by the
company WaveGen
• built in Scotland in 2000
• 500 kW power-output
• OWC (oscillating
water column)
WaveGen
function
principle:
WaveGen
• increase of efficiency by:
1. contraction of the air-tube
Bernoulli:
ptotal pdynamic pstatic const
F
A
2. a turbine with constant direction of rotation (Wells turbine)
Wells Turbine
Wells turbine buildup:
streams on a single blade:
Wells Turbine
• how can this stream create a force ahead:
1. the blade changes
the direction of the
impulse of the air
2. a force is needed
for this change
3. the counterforce
pushes the blade
ahead
Wells Turbine
• but why does the stream change direction ?
Development of a twist around the blade:
1. friction causes
twist
2. twist causes
anti-twist
(conserve of
angular
momentum)
3. twist around
blade and
straight-wind
superpose to
a down-wind
planes fly because:
1. air is an nonideal gas
2. the blades have
a sharp border
3. even symmetric
blades can fly
WaveGen
• ideas for improving WaveGen
– building it further in the sea to increase power-output
– for example integrating it in walls which protect harbors
•
principle is also useable for autarkic buoys
Pelamis
150 m long
3,5 m in diameter
750 tons
Pelamis
• three power modules
between the four
segments
• with two shifted axis
yellow: hydraulic accumulator
blue : hydraulic turbine
Pelamis
• transforming energy:
1.
2.
3.
strong but short wave impulse
accumulator stores pressure
lower but constant release
• how much energy can be produced
– Pelamis converts 80% of wave energy
(defined in watt per meter of wave)
– maximum of 750 kW power-output
– in 2008 the first Pelamis farm was built in Portugal
it produces 2.2 MW enough for 1500 households
Pelamis
ORGIGINALPelamis Wave - Seatrials_WMV V9.wmv
Wave
Dragon
Wave Dragon
• the platform:
• 3 steps:
absorbing (by overtopping) → storing (in reservoir) →
power output (by hydro turbines)
Wave Dragon
• 3 important improvements of efficiency:
– long arms act like reflectors
– the double curved form of the ramp
– adjustable floating height by air-chambers
Wave Dragon
• the first Wave Dragon is actually built (so far a 1:4 prototype)
• real scale dimension:
Distance between
tips of arms
Arm length
Weight
Power output
prototype
real scale
58 m
300 m
28 m
145 m
237 tons
33.000 tons
20 kW
7 MW
a Tapchan System in Norway built in 1989
(stands for TAPered CHANnel)
Overview
WaveGen
Pelamis
Wave Dragon
500 kW
750 kW
7 MW
•WaveGen exists since 2000
in Scotland
•a farm of 3 Pelamis already
exists in Portugal since 2008
•prototype successfully
tested
•a “pre-commercial
demonstrator” is
actually build in Wales
•an equal system is planned
to be built in a harbor
protection wall in Spain
•a new farm with 25 Pelamis
is planned (also in Portugal)
•Now further
information about the
future
My Sources
• Abenteuer Wissen by ZDF:
www.abenteuerwissen.zdf.de
• University Leipzig:
www.uni-leipzig.de/~grw/welle/index.html
• Homepage of Wavegen, Pelamis and Wave Dragon:
www.wavegen.co.uk, www.pelamiswave.com, www.wavedragon.net
The End
Thanks for your attention!