A New Class of Wave Energy Converter: The Floating Pendulum Dynamic Vibration Absorber

2017 ◽  
Author(s):  
Hayden Marcollo ◽  
Jonathan Gumley ◽  
Paul Sincock ◽  
Nicholas Boustead ◽  
Adrian Eassom ◽  
...  
Keyword(s):  
Wave Energy ◽  
Numerical Models ◽  
Low Cost ◽  
Wave Energy Converter ◽  
Floating Body ◽  
Vibration Absorber ◽  
Energy Converter ◽  
Dynamic Vibration Absorber ◽  
New Class ◽  
Dynamic Vibration

A new class of Wave Energy Converter (WEC) is presented — the Floating Pendulum Dynamic Vibration Absorber (FPDVA). This concept offers significant design benefits to other WEC technology in the form of low cost installation and mechanical moving components located above the waterline only. The key elements of the FPDVA concept are highlighted. The performance of the concept is demonstrated through numerical modeling with calibration of the numerical models via physical tank testing. The Power Take Off (PTO) system is described, and the bench tests are presented. A discussion about the control systems required to operate the FPDVA system and the likely floating body mooring configurations are also presented. The technology has patent pending status. Future phased development of the technology is planned to progress its Technology Readiness Level (TRL) status from TRL 4 to TRL 9.

Development of Control Strategies for Interconnected Pneumatic Wave Energy Converters

2017 ◽  
Author(s):  
Eric Thacher ◽  
Helen Bailey ◽  
Bryson Robertson ◽  
Scott Beatty ◽  
Jason Goldsworthy ◽  
...  
Keyword(s):  
Wave Energy ◽  
Time Domain ◽  
Power Output ◽  
Numerical Models ◽  
Control Strategies ◽  
Low Cost ◽  
Optimization Procedure ◽  
Wave Energy Converter ◽  
Energy Converter ◽  
Sea State

In the field of wave energy converter control, high fidelity numerical models have become the predominant tool for the development of accurate and comprehensive control strategies. In this study, a numerical model of a novel wave energy converter, employing a pneumatic power take-off, is created to provide a low-cost method for the development of a power-maximizing control strategy. Device components and associated architectures are developed in the time domain solvers Proteus DS and MATLAB/Simulink. These two codes are dynamically coupled at run time to produce a complete six degree of freedom, time domain simulation of the converter. Utilizing this numerical framework, a genetic algorithm optimization procedure is implemented to optimally select eight independent parameters governing the PTO geometry. Optimality is measured in terms of estimated annual energy production at a specific deployment location off the West Coast of Canada. The optimization exercise is one layer of PTO force control — the parameters selected are seen to provide significant improvements in the annual power output, while also smoothing the WEC power output on both a sea-state by sea-state and wave-by-wave basis.

Numerical Simulation of Duck Wave Energy Converter

2016 ◽  
Vol 693 ◽  
pp. 484-490
Author(s):  
Ying Xue Yao ◽  
Hai Long Li ◽  
Jin Ming Wu ◽  
Liang Zhou
Keyword(s):  
Numerical Simulation ◽  
Wave Energy ◽  
Pitch Angle ◽  
Low Cost ◽  
Three Dimensional ◽  
Angular Frequency ◽  
Wave Energy Converter ◽  
Linear Wave ◽  
Energy Converter ◽  
Flow Theories

Duck wave energy converter has the advantages of high conversion efficiency, simple construction, low cost relative to other wave power device. In the paper, the numerical simulation of the response of the converter was calculated by the AQWA software which based on the three dimensional potential flow theories. The results show that the pitch angle appear the peak when the incident wave frequency is 1rad/s and the maximum of the pitch angle come out as the linear wave normally incident the duck body, which means duck wave energy converter can absorb more wave energy in this angular frequency. The above research can provide reference for the design of the duck wave energy converter.

Array Characteristics of Oscillating-Buoy Two-Floating-Body Wave-Energy Converter

2019 ◽  
Vol 18 (3) ◽  
pp. 325-333
Author(s):  
Renwei Ji ◽  
Qihu Sheng ◽  
Shuqi Wang ◽  
Yuquan Zhang ◽  
Xuewei Zhang ◽  
...  
Keyword(s):  
Wave Energy ◽  
Body Wave ◽  
Wave Energy Converter ◽  
Floating Body ◽  
Energy Converter

scholarly journals Performance analysis of a point-absorber wave energy converter with a single buoy composed of three rigidly coupled structures

2021 ◽  
Vol 4 (2) ◽  
pp. 37-45
Author(s):  
Aldo Ruezga ◽  
José M. Cañedo C. ◽  
Manuel G. Verduzco-Zapata ◽  
Francisco J. Ocampo-Torres
Keyword(s):  
Wave Energy ◽  
Wave Energy Converter ◽  
Floating Body ◽  
Analysis Tool ◽  
Direct Drive ◽  
Energy Converter ◽  
Drive Power ◽  
Point Absorber ◽  
Single Body ◽  
Coupled Structures

A single-body point absorber system is analysed to improve its power absorption at a finite water depth.  The proposed wave energy converter consists of a single floating body coupled to a direct-drive power take-off system placed on the seabed. The structure of a cylindrical buoy with large draft is changed by a single body composed of three structures rigidly coupled, reducing its volume and improving its frequency-dependent hydrostatic parameters that are obtained through a numerical analysis tool called NEMOH. The undamped natural frequency of the oscillating system is tuned to a specified wave period and the performance of the WEC system is obtained assuming a linear Power Take-Off system. In time domain, the performance of the WEC device is carried-out under a regular (sinusoidal) and irregular incident wave profile. Comparing the performance of the WEC system using the cylindrical and the proposed buoy outcomes that the system with the proposed buoy is able to absorb more energy from incident waves with a wider frequency range, whereas the oscillating system is kept as simple as possible.

scholarly journals KNSwing—On the Mooring Loads of a Ship-Like Wave Energy Converter

2019 ◽  
Vol 7 (2) ◽  
pp. 29
Author(s):  
Kim Nielsen ◽  
Jonas Thomsen
Keyword(s):  
Numerical Model ◽  
Wave Energy ◽  
Numerical Models ◽  
Breaking Waves ◽  
Wave Energy Converter ◽  
Experimental Results ◽  
Irregular Waves ◽  
Mooring System ◽  
Energy Converter ◽  
The Waves

The critical function of keeping a floating Wave Energy Converter in position is done by a mooring system. Several WECs have been lost due to failed moorings, indicating that extreme loads, reliability and durability are very important aspects. An understanding of the interaction between the WEC’s motion in large waves and the maximum mooring loads can be gained by investigating the system at model scale supported by numerical models. This paper describes the testing of a novel attenuator WEC design called KNSwing. It is shaped like a ship facing the waves with its bow, which results in low mooring loads and small motions in most wave conditions when the structure is longer than the waves. The concept is tested using an experimental model at scale 1:80 in regular and irregular waves, moored using rubber bands to simulate synthetic moorings. The experimental results are compared to numerical simulations done using the OrcaFlex software. The experimental results show that the WEC and the mooring system survives well, even under extreme and breaking waves. The numerical model coefficient concerning the nonlinear drag term for the surge motion is validated using decay tests. The numerical results compare well to the experiments and, thereby, the numerical model can be further used to optimize the mooring system.

scholarly journals Hydrodynamic Analysis of a Multibody Wave Energy Converter in Regular Waves

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1233
Author(s):  
Sunny Kumar Poguluri ◽  
Dongeun Kim ◽  
Yoon Hyeok Bae
Keyword(s):  
Wave Energy ◽  
Numerical Models ◽  
Wave Energy Converter ◽  
Optimal Time ◽  
Q Factor ◽  
Energy Converter ◽  
Multiple Wave ◽  
Hydrodynamic Analysis ◽  
Heading Angle ◽  
Extracted Power

A performance assessment of wave power absorption characteristics of isolated and multiple wave energy converter (WEC) rotors was presented in this study for various wave-heading angles and wave frequencies. Numerical hydrodynamic analysis of the WEC was carried out using the three-dimensional linear boundary element method (BEM) and nonlinear computational fluid dynamics (CFD). Experimental results were used to validate the adopted numerical models. Influence with and without power take-off (PTO) was estimated on both isolated and multiple WEC rotors. Furthermore, to investigate the interaction effect among WECs, a q-factor was used. Incorporation of viscous and PTO damping into the linear BEM solution shows the maximum reduction focused around peak frequency but demonstrated an insignificant effect elsewhere. The q-factor showed both constructive and destructive interactions with the increase of the wave-heading angle and wave frequencies. Further investigation based on the prototype WEC rotor was carried, and calculated results of the linear BEM and the nonlinear CFD were compared. The pitch response and q-factor of the chosen wave frequencies demonstrated satisfactory consistency between the linear BEM and nonlinear CFD results, except for some wave frequencies. Estimated optimal time-averaged power using linear BEM show that the maximum extracted power close to the zero wave-heading angle around the resonance frequency decreases as the wave-heading angle increases. Overall, the linear BEM on the extracted power is overestimated compared with the nonlinear CFD results.

scholarly journals The performance of the Mocean M100 wave energy converter described through numerical and physical modelling

2020 ◽  
Vol 3 (1) ◽  
pp. 11-19
Author(s):  
J. Cameron McNatt ◽  
Christopher H. Retzler
Keyword(s):  
Frequency Domain ◽  
Wave Energy ◽  
Time Domain ◽  
Numerical Models ◽  
Average Power ◽  
Physical Modelling ◽  
Wave Energy Converter ◽  
Domain Model ◽  
Energy Converter ◽  
Cost Of Energy

Mocean Energy has designed a 100-kW hinged-raft wave energy converter (WEC), the M100, which has a novel geometry that reduces the cost of energy by improving the ratios of power per size and power per torque. The performance of the M100 is shown through the outputs of frequency-domain and time-domain numerical models, which are compared with those from 1/20th scale wave-tank testing. Results show that for the undamped, frequency-domain model, there are resonant peaks in the response at 6.6 and 9.6 s, corresponding to wavelengths that are 1.9 and 3.7 times longer than the machine. With the inclusion of power-take-off and viscous damping, the power response as a function of frequency shows a broad bandwidth and a hinge flex amplitude of 12-20 degrees per meter of wave amplitude. Comparison between the time-domain model and physical data in a variety of sea states, up to a significant wave height of 4.5 m, show agreements within 10% for average power absorption, which is notable because only simple, nonlinear, numerical models were used. The M100 geometry results in a broad-banded, large amplitude response due to its asymmetric shape, which induces coupling between modes of motion.

ISWEC: Design of a Prototype Model for Wave Tank Test

2010 ◽  
Author(s):  
Giovanni Bracco ◽  
Ermanno Giorcelli ◽  
Giuliana Mattiazzo
Keyword(s):  
Wave Energy ◽  
Ocean Waves ◽  
Research Process ◽  
Full Scale ◽  
Wave Energy Converter ◽  
Floating Body ◽  
Prototype Model ◽  
Mathematical Tool ◽  
Energy Converter ◽  
Wave Tank

The extraction of energy from ocean waves has been investigated in Europe since the 1970s. During the research process hundreds of devices have been proposed and a few of them have been built full scale and deployed to the ocean. Unlike other renewable energies, so far there has not been a device standing out to be the most suitable to exploit wave power. One of the practical problems to be solved in a Wave Energy Converter (WEC) is durability in the harsh marine environment. This could be critical if parts of the converter such as turbine rotors or auxiliary floats are needed to move or to react while exposed to seawater and spray. One method to solve the problem is to use a WEC composed just by one sealed floating body carrying a gyroscope. The inertial effects of the gyroscope are activated by the float motion and are used to drive a generator. The whole system operates in the clean environment inside the float. In this work a procedure to design the ISWEC device (Inertial Sea Wave Energy Converter) is outlined. The mechanical equations describing the system are linearized, studied in the frequency domain and used as a mathematical tool in the design process. The method is then applied iteratively to design a scaled prototype model to be tested in the wave tank at the University of Naples. The final version of the prototype model is then scaled up to evaluate the performances of a full scale device.

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