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

Coordinators Overview and Lessons Learned From the Galway Bay Seatrials of the FP7 EU Funded CORES Wave Energy Project

2013 ◽  
Author(s):  
Raymond Alcorn ◽  
Anthony Lewis ◽  
Mark Healy
Keyword(s):  
Renewable Energy ◽  
Wave Energy ◽  
Energy Systems ◽  
Project Manager ◽  
Lessons Learned ◽  
Ocean Energy ◽  
Renewable Energy Systems ◽  
Energy Devices ◽  
Ocean Renewable Energy ◽  
The Coordinator

The paper discusses the lessons learned from the European Funded Framework 7 Research project Components for Ocean Renewable Energy Systems (CORES) which developed and trialed new components and systems for ocean energy devices. The authors are the coordinator and project manager so the paper will give this overview of the project. This will include detail of the work packages, major achievements, significant impacts, summary results and outcomes of the sea trials.

Experimental Investigation of Irregular Wave Cancellation Using a Cycloidal Wave Energy Converter

2012 ◽  
Author(s):  
Stefan G. Siegel ◽  
Casey Fagley ◽  
Marcus Römer ◽  
Thomas McLaughlin
Keyword(s):  
Wave Energy ◽  
Deep Ocean ◽  
Ocean Waves ◽  
Wave Energy Converter ◽  
Irregular Waves ◽  
Energy Converter ◽  
Irregular Wave ◽  
Wave Measurements ◽  
Wave Heights ◽  
Significant Wave Heights

The ability of a Cycloidal Wave Energy Converter (CycWEC) to cancel irregular deep ocean waves is investigated in a 1:300 scale wave tunnel experiment. A CycWEC consists of one or more hydrofoils attached equidistant to a shaft that is aligned parallel to the incoming waves. The entire device is fully submerged in operation. Wave cancellation requires synchronization of the rotation of the CycWEC with the incoming waves, as well as adjustment of the pitch angle of the blades in proportion to the wave height. The performance of a state estimator and controller that achieve this objective were investigated, using the signal from a resistive wave gage located up-wave of the CycWEC as input. The CycWEC model used for the present investigations features two blades that are adjustable in pitch in real time. The performance of the CycWEC for both a superposition of two harmonic waves, as well as irregular waves following a Bretschneider spectrum is shown. Wave cancellation efficiencies as determined by wave measurements of about 80% for the majority of the cases are achieved, with wave periods varying from 0.4s to 0.75s and significant wave heights of Hs ≈ 20mm. This demonstrates that the CycWEC can efficiently interact with irregular waves, which is in good agreement with earlier results obtained from numerical simulations.

Computational Investigation of Irregular Wave Cancelation Using a Cycloidal Wave Energy Converter

2012 ◽  
Author(s):  
Casey P. Fagley ◽  
Jürgen J. Seidel ◽  
Stefan G. Siegel
Keyword(s):  
Wave Energy ◽  
Flow Simulation ◽  
Deep Ocean ◽  
Ocean Waves ◽  
Operating Conditions ◽  
Wave Energy Converter ◽  
Energy Converter ◽  
Incoming Wave ◽  
Wave State ◽  
Irregular Wave

The ability of a Cycloidal Wave Energy Converter (CycWEC) to cancel irregular deep ocean waves is investigated in a time integrated, inviscid potential flow simulation. A CycWEC consists of one or more hydrofoils attached eccentrically to a shaft that is aligned parallel to the incoming waves. The entire device is fully submerged in operation. A Bretschneider spectrum with 40 discrete components is used to model an irregular wave environment in the simulations. A sensor placed up-wave of the CycWEC measures the incoming wave height and provides a signal for the wave state estimator, a non-causal Hilbert transformation, to estimate the instantaneous frequency, phase and amplitude of the irregular wave pattern. A linear control scheme which proportionally controls hydrofoil pitch and compensates for phase delays is adopted. Efficiency for the design Bretschneider spectrum shows more than 99% efficiency, while non-optimum, off design operating conditions still maintain more than 85% efficiency. These results are in agreement with concurrent experimental results obtained at a 1:300 scale.

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.

Conceptual Design of OWC Wave Energy Converters Combined With Breakwater Structures

2010 ◽  
Author(s):  
Vallam Sundar ◽  
Torgeir Moan ◽  
Jo̸rgen Hals
Keyword(s):  
Wave Energy ◽  
Ocean Waves ◽  
Floating Bodies ◽  
Energy Device ◽  
Energy Devices ◽  
Wave Energy Converters ◽  
Ocean Wave Energy ◽  
Caisson Breakwater ◽  
Perforated Caisson ◽  
Energy Converters

Ocean wave energy is one of several renewable sources of energy found in the ocean. The energy in the oscillatory ocean waves can be used to drive a machinery that converts the energy to other forms. Depending on the type and their location with respect the coast and offshore, a number of devices have been and are being developed to extract the wave energy for conversion into electricity. The most common devices are referred to as the oscillating water column (OWC), hinged contour device, buoyant moored device, hinged flap and overtopping device. Particularly popular are OWCs and moored floating bodies. The idea of integrating breakwater and wave energy converters emerged in the Indian wave energy program. Graw (1996) discussed this idea and pointed out the advantage of shared costs between the breakwater and the wave energy device. Because long waves are usually experience stronger reflection at coasts and breakwaters, they provide good conditions for the operation wave energy devices which work efficiently when the reflection is high. There are examples that OWC devices have been installed in water as shallow as 3 m. This paper reviews the options of integrating OWCs with different kinds of breakwaters like the perforated or non-perforated caisson breakwater, and non-gravity piled and floating types. The purpose of each of the concepts will also be highlighted.

Hydro-Dynamic Simulation of a Cylinder Buoy for Wave Energy Conversion

2011 ◽  
Author(s):  
Carlos Velez ◽  
Brent Papesh ◽  
Marcel Ilie ◽  
Zhihua Qu
Keyword(s):  
Renewable Energy ◽  
Wave Energy ◽  
Fossil Fuels ◽  
Electrical Power ◽  
Vertical Motion ◽  
Ocean Waves ◽  
Offshore Structures ◽  
Wave Energy Conversion ◽  
Energy Potential ◽  
Relative Water

Development of technology to harness the vast amount of renewable energy available in nature has been ever-increasing in popularity. A worldwide desire to limit dependency on fossil fuels as a means to produce power has motivated research in solar, wind, and wave energies, as well as other clean, naturally-abundant energy sources. With a density approximately 1000 times greater than air, the energy potential of ocean water is tremendous, and it is capable of providing power to locations in which other forms of renewable energy are not applicable—namely coastal regions with minimal wind or sunshine, or offshore structures. This research details the hydro-dynamic modeling of an innovative buoy design for a wave energy harvester that converts the heaving motion of waves into electrical power. Power is generated through the use of a bi-directional turbine which is driven by the relative water velocity created by the heaving buoy. In order to predict the changing velocity profile in which the bi-directional turbine will experience, a hydro-dynamic model has been created with a smoother particle hydro-dynamics code, SPHysics. The model can accurately simulate the motion of the buoy as it is excited by various ocean waves for different ocean depths. In order to maximize the flow velocity through the turbine, various geometric parameters will be altered to attempt to have the buoy and ocean wave perfectly out of phase. Additionally, the buoys stability is studied to determine the optimal geometry to promote a vertical motion as any yaw or pitching motion can not be harnessed by the bi-directional turbine.

scholarly journals Dynamic Response of Coupled Mooring Lines and Floating Wave Energy Devices in Waves / Currents

2019 ◽  
Vol 8 (12) ◽  
pp. 5539-5545
Keyword(s):  
Renewable Energy ◽  
Dynamic Response ◽  
Wave Energy ◽  
Degrees Of Freedom ◽  
Ocean Waves ◽  
Irregular Waves ◽  
Mooring Lines ◽  
Energy Devices ◽  
Six Degrees Of Freedom ◽  
The Government

Various global studies have shown that ocean waves energy have large potential in renewable energy sector. Their role within renewable energy gets high priority in the future by the government of United Kingdom. The principle concept of wave energy is when wave energy is converted into potential energy by the wave energy devices to generate electricity. An understanding of the dynamic response of the devices and mooring lines is important for this paper. This paper deals with the analysis of the various effects that influence the different design of wave energy converter devices. The mooring design idea is also analyzed to show which mooring layout is suitable to fulfill the requirement. The design of mooring configuration also influence how wave power is extracted and how such system are operated and maintained. The effects investigated in this paper are regular and irregular waves, motion @ six degrees of freedom, maximum and minimum mooring tension, different waves direction, wave current, energy and power take off.

What can wave energy learn from offshore oil and gas?

2012 ◽  
Vol 370 (1959) ◽  
pp. 439-450 ◽  
Author(s):  
E. R. Jefferys
Keyword(s):  
Wave Energy ◽  
Oil And Gas ◽  
Offshore Structures ◽  
Lessons Learned ◽  
Field Development ◽  
Oil And Gas Exploration ◽  
Energy Devices ◽  
Playing Field ◽  
The Past ◽  
Reliability Based Design

This title may appear rather presumptuous in the light of the progress made by the leading wave energy devices. However, there may still be some useful lessons to be learnt from current ‘offshore’ practice, and there are certainly some awful warnings from the past. Wave energy devices and the marine structures used in oil and gas exploration as well as production share a common environment and both are subject to wave, wind and current loads, which may be evaluated with well-validated, albeit imperfect, tools. Both types of structure can be designed, analysed and fabricated using similar tools and technologies. They fulfil very different missions and are subject to different economic and performance requirements; hence ‘offshore’ design tools must be used appropriately in wave energy project and system design, and ‘offshore’ cost data should be adapted for ‘wave’ applications. This article reviews the similarities and differences between the fields and highlights the differing economic environments; offshore structures are typically a small to moderate component of field development cost, while wave power devices will dominate overall system cost. The typical ‘offshore’ design process is summarized and issues such as reliability-based design and design of not normally manned structures are addressed. Lessons learned from poor design in the past are discussed to highlight areas where care is needed, and wave energy-specific design areas are reviewed. Opportunities for innovation and optimization in wave energy project and device design are discussed; wave energy projects must ultimately compete on a level playing field with other routes to low CO 2 energy and/or energy efficiency. This article is a personal viewpoint and not an expression of a ConocoPhillips position.

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