CG: n
CT: Floating buoys have been developed which can generate energy from the bobbing or pitching motion caused by the waves. In some buoy type systems the buoy uses a simple mechanical system to turn a crankshaft. For example, in the Indian I-wave system the wave action raises the heavy partially buoyant piston that drives the overhead crankshaft by half turn. The receding wave drops the piston completing the balance half turn. One revolution is obtained for every wave. Using a gear box and a generator the current is produced continuously.
S: WE – http://www.energybible.com/water_energy/wave_energy_systems.html (last access: 10 December 2014)
N: 1. floating (adj): from float (v). Late Old English flotian “to rest on the surface of water” (intransitive; class II strong verb; past tense fleat, past participle floten), from Proto-Germanic *flotan “to float”.
buoy (n): late 13c., perhaps from either Old French buie or Middle Dutch boeye, both from West Germanic *baukna “beacon, signal”.
2. Vertical buoys can also be used in a similar manner to move a piston up and down which contains a permanent magnet. The magnet is surrounded by a copper wire coil. As the magnet moves back and forth through the coil an electric current is automatically generated. One of the advantages of this approach is that the current is produced directly without the need of a generator.
3. The buoy approach can be used with both vertical and horizontal types of buoys. An example of a horizontal buoy is the Pelamis wave energy converter which uses semi-submerged cylinders linked by hinged joints. It looks a lot like a sea serpent in the water and so was named after the Pelamis sea snake. Inside each cylinder there is a hydraulic ram which pumps high-pressure oil through hydraulic motors. The hydraulic motors in turn drive electrical generators inside the cylinder. Many of these cylinders can be combined and then the energy can be fed to an underground sea cable and back to shore.
4. The University of Exeter owns and operates Oceanor Seawatch mini II floating wave buoys. These buoys are particle following and provide time-series of surface displacements in Vertical, East and North directions. Data are processed to give directional wave spectra and a full range of summary parameters, which are transmitted in real time to a shore station, via either the radio or mobile network. Through multiple successful deployments to date, these buoys have demonstrated that they are robust and provide high quality, accurate measurements.
5. Cultural Interrelation: Archimedes’ principle, physical law of buoyancy, discovered by the ancient Greek mathematician and inventor Archimedes, stating that any body completely or partially submerged in a fluid (gas or liquid) at rest is acted upon by an upward, or buoyant, force the magnitude of which is equal to the weight of the fluid displaced by the body.
S: 1. OED – http://www.etymonline.com/index.php?allowed_in_frame=0&search=float&searchmode=none; http://www.etymonline.com/index.php?allowed_in_frame=0&search=buoy&searchmode=none. 2 & 3. WE – http://www.energybible.com/water_energy/wave_energy_systems.html (last access: 10 December 2014). 4. EXETER – http://emps.exeter.ac.uk/renewable-energy/research/research-interests/offshore/resource-assessment/facilities/floatingwavebuoys/ (last access: 10 December 2014). 5. EncBrit – http://global.britannica.com/EBchecked/topic/32827/Archimedes-principle (last access: 31 March 2015).
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CR: bathymetry, ocean wave energy, tidal power, [wave powered plant]
