scholarly journals A novel wave-energy device with enhanced wave amplification and induction actuator

2020 ◽  
Vol 3 (1) ◽  
pp. 37-44
Author(s):  
Onno Bokhove ◽  
Anna Kalogirou ◽  
David Henry ◽  
Gareth P. Thomas
Keyword(s):  
Variational Principle ◽  
Numerical Model ◽  
Energy Conversion ◽  
Wave Energy ◽  
Electrical Power ◽  
Rogue Waves ◽  
Energy Device ◽  
Wave Amplification ◽  
Energy Devices ◽  
New Device

A novel wave-energy device is presented. Both a preliminary proof-of-principle of a working, scaled laboratory version of the energy device is shown as well as the derivation and analysis of a comprehensive mathematical and numerical model of the new device. The wave-energy device includes a convergence in which the waves are amplified, a constrained wave buoy with a (curved) mast and direct energy conversion of the buoy motion into electrical power via an electro-magnetic generator. The device is designed for use in breakwaters and it is possible to be taken out of action during severe weather. The new design is a deconstruction of elements of existing wave-energy devices, such as the TapChan, IP wave-buoy and the Berkeley Wedge, put together in a different manner to enhance energy conversion and, hence, efficiency. The idea of wave-focusing in a contraction emerged from our work on creating and simulating rogue waves in crossing seas, including a "bore-soliton-splash". Such crossing seas have been recreated and modelled in the laboratory and in simulations by using a geometric channel convergence. The mathematical and numerical modelling is also novel. One monolithic variational principle governs the dynamics including the combined (potential-flow) hydrodynamics, the buoy motion and the power generation, to which the dissipative elements such as the electrical resistance of the circuits, coils and loads have been added a posteriori. The numerical model is a direct and consistent discretisation of this comprehensive variational principle. Preliminary numerical calculations are shown for the case of linearised dynamics; optimisation of efficiency is a target of future work.

An Experimental Study of the Performance of the Counter-Rotating Wave Energy Conversion Turbine

1989 ◽  
Vol 111 (3) ◽  
pp. 167-173 ◽  
Author(s):  
M. E. McCormick ◽  
S. W. Surko
Keyword(s):  
Experimental Study ◽  
Energy Conversion ◽  
Water Column ◽  
Wave Energy ◽  
Electrical Power ◽  
Wave Crest ◽  
Maximum Efficiency ◽  
Wave Energy Conversion ◽  
Conversion System ◽  
Energy Conversion System

Results of an experimental study of a counter-rotating turbine operating on a pneumatic wave energy conversion system are presented. The vertical capture chamber of the water column of the system has a down-facing water intake. An electrical generator (d-c) is coupled to the turbine by a ten-gear-ratio drive train. Tests of the pneumatic wave energy conversion system were conducted with the mouth at two depths in order to vary the natural oscillating frequency of the water column. The maximum electrical power output of the system was approximately 90 W in the monochromatic waves. This value corresponds to a 36-percent efficiency based on the incident wave power in a wave crest width equal to the diameter of the capture chamber. The theoretical maximum efficiency of such a system has been shown to be 50 percent by several investigators.

scholarly journals Primary energy conversion performance of “Pendulor” wave energy device with bottom gap

2020 ◽  
Vol 44 (4) ◽  
pp. 338-343
Author(s):  
Lekha. U. Bakmeedeniya ◽  
S.D.G.S.P. Gunawardane ◽  
Byung-Ha Kim ◽  
Young-Ho Lee
Keyword(s):  
Energy Conversion ◽  
Wave Energy ◽  
Primary Energy ◽  
Energy Device ◽  
Conversion Performance

scholarly journals Deep ocean wave energy systems (DOWES): experimental investigations

2014 ◽  
Vol 11 (2) ◽  
pp. 139-146 ◽  
Author(s):  
Srinivasan Chandrasekaran ◽  
Deepak C Raphel ◽  
Sai Shree
Keyword(s):  
Wave Energy ◽  
Energy Systems ◽  
Deep Ocean ◽  
Ocean Waves ◽  
Offshore Structures ◽  
Green Energy ◽  
Experimental Investigations ◽  
Energy Devices ◽  
New Device ◽  
Operational Energy

Deep water offshore structures have access to very powerful ocean waves by virtue of their location and site condition. Should the energy possessed by these waves be harnessed, it can be one of the popular green energy systems. Present study aims at the design and development of a new device that can be fitted on an offshore semisubmersible platform and can produce electricity to meet their operational energy demands partially. Few wave energy devices are developed in the recent past; Common idea in all such devices is that they harness heave, or surge energy of the wave. In the present study, heave energy of the buoy is converted to mechanical work by deploying hydraulic cylinders and a motor. The generated power from the waves shall be primarily utilized in the semi-submersible platform for deep sea mining application.DOI: http://dx.doi.org/10.3329/jname.v11i2.18420

scholarly journals Electrical Power Generation from the Oceanic Wave for Sustainable Advancement in Renewable Energy Technologies

2020 ◽  
Vol 12 (6) ◽  
pp. 2178 ◽  
Author(s):  
Omar Farrok ◽  
Koushik Ahmed ◽  
Abdirazak Dahir Tahlil ◽  
Mohamud Mohamed Farah ◽  
Mahbubur Rahman Kiran ◽  
...  
Keyword(s):  
Power Generation ◽  
Renewable Energy ◽  
Electrical Power Generation ◽  
Wave Energy ◽  
Electrical Power ◽  
Extensive Literature ◽  
Energy Devices ◽  
Wave Energy Converters ◽  
Oceanic Wave ◽  
Energy Converters

Recently, electrical power generation from oceanic waves is becoming very popular, as it is prospective, predictable, and highly available compared to other conventional renewable energy resources. In this paper, various types of nearshore, onshore, and offshore wave energy devices, including their construction and working principle, are explained explicitly. They include point absorber, overtopping devices, oscillating water column, attenuators, oscillating wave surge converters, submerged pressure differential, rotating mass, and bulge wave converter devices. The encounters and obstacles of electrical power generation from the oceanic wave are discussed in detail. The electrical power generation methods of the generators involved in wave energy devices are depicted. In addition, the vital control technologies in wave energy converters and devices are described for different cases. At present, piezoelectric materials are also being implemented in the design of wave energy converters as they convert mechanical motion directly into electrical power. For this reason, various models of piezoelectric material-based wave energy devices are illustrated. The statistical reports and extensive literature survey presented in this review show that there is huge potential for oceanic wave energy. Therefore, it is a highly prospective branch of renewable energy, which would play a significant role in the near future.

scholarly journals From Bore–Soliton–Splash to a New Wave-to-Wire Wave-Energy Model

Water Waves ◽  
2019 ◽  
Vol 1 (2) ◽  
pp. 217-258
Author(s):  
O. Bokhove ◽  
A. Kalogirou ◽  
W. Zweers
Keyword(s):  
Wave Energy ◽  
Water Wave ◽  
Weak Sense ◽  
Energy Model ◽  
Energy Device ◽  
Element Space ◽  
Experimental Proof ◽  
Wave Amplification ◽  
Time Discretisation ◽  
Correct Energy

AbstractWe explore extreme nonlinear water-wave amplification in a contraction or, analogously, wave amplification in crossing seas. The latter case can lead to extreme or rogue-wave formation at sea. First, amplification of a solitary-water-wave compound running into a contraction is disseminated experimentally in a wave tank. Maximum amplification in our bore–soliton–splash observed is circa tenfold. Subsequently, we summarise some nonlinear and numerical modelling approaches, validated for amplifying, contracting waves. These amplification phenomena observed have led us to develop a novel wave-energy device with wave amplification in a contraction used to enhance wave-activated buoy motion and magnetically induced energy generation. An experimental proof-of-principle shows that our wave-energy device works. Most importantly, we develop a novel wave-to-wire mathematical model of the combined wave hydrodynamics, wave-activated buoy motion and electric power generation by magnetic induction, from first principles, satisfying one grand variational principle in its conservative limit. Wave and buoy dynamics are coupled via a Lagrange multiplier, which boundary value at the waterline is in a subtle way solved explicitly by imposing incompressibility in a weak sense. Dissipative features, such as electrical wire resistance and nonlinear LED loads, are added a posteriori. New is also the intricate and compatible finite-element space–time discretisation of the linearised dynamics, guaranteeing numerical stability and the correct energy transfer between the three subsystems. Preliminary simulations of our simplified and linearised wave-energy model are encouraging and involve a first study of the resonant behaviour and parameter dependence of the device.

Life cycle comparison of a wave and tidal energy device

2011 ◽  
Vol 225 (4) ◽  
pp. 325-337 ◽  
Author(s):  
S Walker ◽  
R Howell
Keyword(s):  
Life Cycle ◽  
Wave Energy ◽  
Tidal Energy ◽  
Development Stage ◽  
Payback Period ◽  
Energy Device ◽  
Energy Mix ◽  
Energy Devices ◽  
Marine Energy ◽  
Marine Current

Tidal and wave energy devices are often discussed as a future contributor to the UK’s energy mix. Indeed, marine energy resources are said to have the potential to supply up to 20 per cent of the nation’s electricity demand. However, these technologies are currently at the development stage and make no meaningful contribution to the national grid. A number of devices have been developed, but no single method has emerged as the leading technology. This paper aims to compare two promising devices, one wave device and one tidal device, and assess the life cycle properties of each. A life cycle assessment of the Oyster wave energy device was conducted as part of this study, and a comparison of this and the SeaGen marine current turbine was undertaken. In both cases a ‘cradle-to-grave’ assessment was carried out, calculating emissions from materials, fabrication, transport, installation, lifetime maintenance, and decommissioning (including recycling). The SeaGen tidal device was calculated to have an energy payback period of 14 months, and a CO2 payback period of 8 months. The equivalent figures for the Oyster device were 12 and 8 months, respectively. The respective energy and carbon intensities for the two devices were 214 kJ/kWh and 15 gCO2/kWh for the SeaGen and 236 kJ/kWh and 25 gCO2/kWh for the Oyster. The calculated intensities and payback periods are close to those of established wind turbine technologies, and low relative to the 400–1000 g CO2/kWh of typical fossil fuel generation. With further developments in construction and deployment efficiency these intensities are expected to fall, so the devices appear to have the potential to offer a viable contribution to the UK’s future energy mix.

Development of an electrical power take off system for a sea-test scaled offshore wave energy device

2011 ◽  
Vol 36 (4) ◽  
pp. 1236-1244 ◽  
Author(s):  
Dara O’Sullivan ◽  
James Griffiths ◽  
Michael G. Egan ◽  
Anthony W. Lewis
Keyword(s):  
Wave Energy ◽  
Electrical Power ◽  
Energy Device ◽  
Offshore Wave

Floating Wave Energy Device With Two Oscillating Water Columns

2007 ◽  
Author(s):  
D. C. Hong ◽  
S. Y. Hong
Keyword(s):  
Green Function ◽  
Wave Energy ◽  
Numerical Results ◽  
The Body ◽  
Energy Device ◽  
Energy Devices ◽  
Damping Parameter ◽  
Absorbed Power ◽  
Linear Damping ◽  
Drift Force

The absorbed power, motion and drift force of a floating wave energy device with two oscillating water column (OWC) chambers are studied taking account of the interaction between two chambers within the scope of the linear wave theory. The oscillating surface-pressure in the OWC chamber is represented by a product of the air-flow velocity and an equivalent linear damping parameter. The two-dimensional potential problem is formulated as a hybrid Green integral equation using the Rankine Green function inside the chamber and the finite-depth free-surface Green function outside respectively. The present numerical method makes it possible to tune the OWC and the floating body motions to the incident waves that is essential to maximize the absorbed power. The absorbed powers are calculated by both the near-field and far-field methods for various values of the linear damping parameter in two chambers. The reflection and transmission coefficients of the body are also presented. The numerical results for one OWC devices where the OWC is placed in a backward and forward bent duct buoys (BBDB and FBDB) are also presented for comparison of the performance. The present floating wave energy devices can also be served as a good floating breakwater having small drift force. The present numerical results show that the existence of reverse time-mean horizontal wave drift force is not contradictory to the principle of wave energy conservation.

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