Performance assessments of the fully submerged sphere and cylinder point absorber wave energy converters

2019 ◽  
Vol 33 (13) ◽  
pp. 1950168 ◽  
Author(s):  
Qianlong Xu ◽  
Ye Li ◽  
Yingkai Xia ◽  
Weixing Chen ◽  
Feng Gao
Keyword(s):  
Wave Height ◽  
Wave Energy ◽  
Interaction Analysis ◽  
Wave Power ◽  
Viscous Damping ◽  
Power Performance ◽  
Point Absorber ◽  
Wave Energy Converters ◽  
Submerged Sphere ◽  
Energy Converters

Fully submerged sphere and cylinder point absorber (PA), wave energy converters (WECs) are analyzed numerically based on linearized potential flow theory. A boundary element method (BEM) (a radiation–diffraction panel program for wave-body interactions) is used for the basic wave-structure interaction analysis. In the present numerical model, the viscous damping is modeled by an equivalent linearized damping which extracts the same amount of wave energy over one cycle as the conventional quadratic damping term. The wave power capture width in each case is predicted. Comparisons are also made between the sphere and cylinder PAs which have identical geometrical scales and submerged depths. The results show that: (i) viscous damping has a greater influence on wave power performance of the cylinder PA than that of the sphere PA; (ii) the increasing wave height reduces wave power performance of PAs; (iii) the cylinder PA has a better wave power performance compared to the sphere PA in larger wave height scenarios, which indicates that fully submerged cylinder PA is a preferable prototype of WEC.

Wave power performance of wave energy converters at high-energy areas of a semi-enclosed sea

Energy ◽  
2021 ◽  
Vol 220 ◽  
pp. 119705
Author(s):  
Ajab Gul Majidi ◽  
Bilal Bingölbali ◽  
Adem Akpınar ◽  
Eugen Rusu
Keyword(s):  
Wave Energy ◽  
High Energy ◽  
Wave Power ◽  
Power Performance ◽  
Wave Energy Converters ◽  
Energy Converters

scholarly journals Hardware-in-the-Loop Validation of Model Predictive Control of a Discrete Fluid Power Power Take-Off System for Wave Energy Converters

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3668
Author(s):  
Anders H. Hansen ◽  
Magnus F. Asmussen ◽  
Michael M. Bech
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Wave Energy ◽  
Fluid Power ◽  
Wave Power ◽  
Reactive Control ◽  
Power Extraction ◽  
Wave Energy Converters ◽  
Extraction Algorithm ◽  
Energy Converters

Model predictive control based wave power extraction algorithms have been developed and found promising for wave energy converters. Although mostly proven by simulation studies, model predictive control based algorithms have shown to outperform classical wave power extraction algorithms such as linear damping and reactive control. Prediction models and objective functions have, however, often been simplified a lot by for example, excluding power take-off system losses. Furthermore, discrete fluid power forces systems has never been validated experimentally in published research. In this paper a model predictive control based wave power extraction algorithm is designed for a discrete fluid power power take-off system. The loss models included in the objective function are based on physical models of the losses associated with discrete force shifts and throttling. The developed wave power extraction algorithm directly includes the quantized force output and the losses models of the discrete fluid power system. The experimental validation of the wave power extraction algorithm developed in the paper shown an increase of 14.6% in yearly harvested energy when compared to a reactive control algorithm.

Experimental and numerical comparisons of self-reacting point absorber wave energy converters in regular waves

2015 ◽  
Vol 104 ◽  
pp. 370-386 ◽  
Author(s):  
Scott J. Beatty ◽  
Matthew Hall ◽  
Bradley J. Buckham ◽  
Peter Wild ◽  
Bryce Bocking
Keyword(s):  
Wave Energy ◽  
Regular Waves ◽  
Numerical Comparisons ◽  
Point Absorber ◽  
Wave Energy Converters ◽  
Energy Converters

Introducing Wave Regeneration by Wind in a Mild-Slope Wave Propagation Model MILDwave to Investigate the Wake Effects in the Lee of a Farm of Wave Energy Converters

2011 ◽  
Author(s):  
Vasiliki Stratigaki ◽  
Peter Troch ◽  
Leen Baelus ◽  
Yannick Keppens
Keyword(s):  
Wave Propagation ◽  
Wave Energy ◽  
Propagation Model ◽  
Wave Power ◽  
Single Wave ◽  
Wave Energy Converters ◽  
Wake Effects ◽  
Wave Regeneration ◽  
Wave Propagation Model ◽  
Energy Converters

The increasing energy demand, the need to reduce greenhouse gas emissions and the shrinking reserves of fossil fuels have all enhanced the interest in sustainable and renewable energy sources, including wave energy. Many concepts for wave power conversion have been invented. In order to extract a considerable amount of wave power, single Wave Energy Converters (abbreviated as WECs) will have to be arranged in arrays or ‘farms’ using a particular geometrical layout, comprising large numbers of devices. As a result of the interaction between the WECs within a farm, the overall power absorption is affected. In general, the incident waves are partly reflected, transmitted and absorbed by a single WEC. Also, the wave height behind a large farm of WECs is reduced and this reduction may influence neighbouring farms, other users in the sea or even the coastline (wake effects of a WEC farm). The numerical wave propagation model MILDwave has been recently used to study wake effects and energy absorption of farms of WECs, though without taking into account wave regeneration by wind in the lee of the WEC-farm which can be significant in large distances downwave the WECs. In this paper, the implementation of wave growth due to wind in the hyperbolic mild-slope equations of the wave propagation model, MILDwave is described. Several formulations for the energy input from wind found in literature are considered and implemented. The performance of these formulations in MILDwave is investigated and validated. The modified model MILDwave is then applied for the investigation of the influence of the wind on the wakes in the lee of a farm of wave energy converters.

Basic Characteristics of the Primary Conversion of an OWC Type WEC Installed on a Wave Dissipating Double-Caisson

2018 ◽  
Author(s):  
Tomoki Ikoma ◽  
Koichi Masuda ◽  
Hiroaki Eto ◽  
Shogo Shibuya
Keyword(s):  
Wave Height ◽  
Basic Property ◽  
Wave Energy ◽  
Wave Power ◽  
Oscillating Water Column ◽  
Type Wave ◽  
Wave Energy Converters ◽  
The World ◽  
Fixed Type ◽  
Basic Characteristics

Several types of oscillating water column (OWC) type wave energy converters (WECs) are researched and developed in the world. They are floating types and fixed types. In case of a fixed type, wave dissipating caissons could be replaced to WECs of an OWC type. On OWC types, installation of the projecting-walls (PWs) is useful in order to improve PTO performance. In this study, it was considered that a double dissipating caisson was used as an OWC type WEC with PWs. A front caisson of the double caisson seems the area surrounded by PWs and a back caisson can be seen as an OWC. The paper studied basic property of the primary conversion from wave power to power of air from model tests in a wave tank. As a result, wave height strongly effects on behaviours of OWC motion as well as air pressure. Finally, the primary conversion was affected by wave height. Besides, the concept of use of a double caisson was useful from the primary conversion over 80 % evaluated using test data.

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