Numerical Assessment on Primary Wave Energy Conversion of Oscillating Water Columns

2014 ◽  
Author(s):  
Wanan Sheng ◽  
Ray Alcorn ◽  
Tony Lewis
Keyword(s):  
Dynamic System ◽  
Energy Conversion ◽  
Wave Energy ◽  
Primary Wave ◽  
Wave Energy Conversion ◽  
Wave Energy Converters ◽  
Numerical Assessment ◽  
Water Columns ◽  
Oscillating Water Columns ◽  
Energy Converters

Oscillating water column (OWC) wave energy converters (WECs) are probably the simplest and most promising wave energy converters due to their good feasibility, reliability and survivability in practical wave energy conversions and also regarded as the most studied and developed when compared to other types of the wave energy converters. This research aims to develop a reliable numerical tool to assess the performance of the OWC wave energy converters, particularly in the primary wave energy conversion. In the numerical assessment tool, the hydrodynamics of the device and thermodynamics of the air chamber can be studied separately. However, for the complete dynamic system when a power takeoff (PTO) system is applied, these two dynamic systems are fully coupled in time-domain, in which the PTO can have a simple mathematical expression as the relation between the pressure difference across the PTO (the chamber pressure) and its flowrate through the PTO. And the application of a simple PTO pressure-flowrate relation very much simplifies the complicated aerodynamics and thermodynamics in the air turbine system so the whole dynamic system can be simplified. The methodology has been applied to a generic OWC device and the simulation results have been compared to the experimental data. It is shown that the developed numerical method is reliable in and capable of assessing the primary wave energy conversion of oscillating water columns.

scholarly journals Numerical Assessment of Onshore Wave Energy in France: Wave Energy, Conversion and Cost

2020 ◽  
Vol 8 (11) ◽  
pp. 947
Author(s):  
Philippe Sergent ◽  
Virginie Baudry ◽  
Arnaud De Bonviller ◽  
Bertrand Michard ◽  
Jérémy Dugor
Keyword(s):  
Wave Energy ◽  
Atlantic Coast ◽  
Production Costs ◽  
Wave Energy Conversion ◽  
Wave Energy Converters ◽  
Cost Of Energy ◽  
Numerical Assessment ◽  
Depth Analysis ◽  
Water Columns ◽  
Oscillating Water Columns

There are few general analyses of the interest of onshore wave energy converters (onshore WEC) in terms of resources, efficiency and cost. The case of The Channel on the Atlantic coast of France is chosen here to illustrate the issues related to onshore WEC development. The paper presents a list of potential sites with their characteristics and a more in-depth analysis of a few sites. For four onshore WEC families, the production is given with a method of calculating the efficiency and economic analysis is carried out to estimate the energy cost at two selected sites. Annual wave power levels are maximum in Bayonne with 24 kW/m, and the lengths of useful dikes vary from 60 m in Molène up to 4000 m in Cherbourg. Wave reflection on the dike is an advantage in terms of energy production. The oscillating flaps constitute the systems with the highest efficiency, and the float systems have the lowest levelized cost of energy (LCoE), followed closely by the oscillating flaps. Oscillating water columns and overtopping systems have nearly five times these LCoEs. With mass production, costs of oscillating floats and flaps will approach those of other renewable energies such as solar and wind power.

scholarly journals A Survey of Power Take-off Systems of Ocean Wave Energy Converters

2019 ◽  
Author(s):  
Zhenwei Liu ◽  
Ran Zhang ◽  
Han Xiao ◽  
Xu Wang
Keyword(s):  
Energy Conversion ◽  
Wave Energy ◽  
Clean Energy ◽  
Ocean Wave ◽  
Direct Drive ◽  
Wave Energy Conversion ◽  
Drive Power ◽  
Wave Energy Converters ◽  
Ocean Wave Energy ◽  
Energy Converters

Ocean wave energy conversion as one of the renewable clean energy sources is attracting the research interests of many people. This review introduces different types of power take-off technology of wave energy converters. The main focus is the linear direct drive power take-off devices as they have the advantages for ocean wave energy conversion. The designs and optimizations of power take-off systems of ocean wave energy converters have been studied from reviewing the recently published literature. Also, the simple hydrodynamics of wave energy converters have been reviewed for design optimization of the wave energy converters at specific wave sites. The novel mechanical designs of the power take-off systems have been compared and investigated in order to increase the energy harvesting efficiency.

On the Array of Wave Energy Converters: The Case of the Coaxial-Duct OWC

2018 ◽  
Author(s):  
J. C. C. Portillo ◽  
J. C. C. Henriques ◽  
R. P. F. Gomes ◽  
L. M. C. Gato ◽  
A. F. O. Falcão
Keyword(s):  
Wave Energy ◽  
Oscillating Water Column ◽  
Economic Activities ◽  
Energy Converter ◽  
Diverse Range ◽  
Wave Energy Converters ◽  
Large Size ◽  
New Findings ◽  
Water Columns ◽  
Oscillating Water Columns

This work focuses on the initial performance assessment of an array of coaxial-duct (CD) oscillating-water-columns (owc’s) with potential to be used as multipurpose platform for the creation of value in a diverse range of offshore economic activities. The coaxial-duct owc (CD-owc) is an axisymmetric oscillating-water-column wave energy converter that has been studied for both small-size and large-size applications. This work focuses on buoys of 12 meter diameter distributed in an array of five devices, rigidly attached to each other, to form a cluster of owc’s. The objective of the study is to assess the performance of the array with this configuration and estimate the effect of parameters such as distance between devices, various modes of movements, and other constraints on the overall power output of the array. Results of different cases are compared to the performance of an isolated device to determine the interference effect of other devices. Some results validate previous research conclusions and new findings on the behavior coaxial-duct owc are presented.

scholarly journals Control Strategies Applied to Wave Energy Converters: State of the Art

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3115 ◽  
Author(s):  
Aleix Maria-Arenas ◽  
Aitor J. Garrido ◽  
Eugen Rusu ◽  
Izaskun Garrido
Keyword(s):  
Energy Conversion ◽  
Natural Frequency ◽  
Wave Energy ◽  
State Of The Art ◽  
Control Strategies ◽  
Resonance Mode ◽  
Wave Energy Conversion ◽  
Safe Operation ◽  
Incoming Wave ◽  
Wave Energy Converters

Wave energy’s path towards commercialization requires maximizing reliability, survivability, an improvement in energy harvested from the wave and efficiency of the wave to wire conversion. In this sense, control strategies directly impact the survivability and safe operation of the device, as well as the ability to harness the energy from the wave. For example, tuning the device’s natural frequency to the incoming wave allows resonance mode operation and amplifies the velocity, which has a quadratic proportionality to the extracted energy. In this article, a review of the main control strategies applied in wave energy conversion is presented along their corresponding power take-off (PTO) systems.

scholarly journals Analysis of Wave Energy Conversion with Dynamic Systems Theory

2019 ◽  
Vol 103 ◽  
pp. 02003
Author(s):  
Sorin Ciortan ◽  
Eugen Rusu
Keyword(s):  
Dynamic System ◽  
Energy Conversion ◽  
Wave Energy ◽  
Prediction Models ◽  
Weather Conditions ◽  
Point Of View ◽  
The Black Sea ◽  
Time Range ◽  
Wave Energy Conversion ◽  
Dynamic System Theory

In wave energy conversion one of the most important steps is building scenarios about long term efficiency, taking into account that several factors are involved. Based on the assumption that actually the weather conditions show important modifications year by year, analyses of wave power evolution during the exploitation time range must rely on both prediction models and on several options for the conversion device. From this point of view, the wave energy conversion process can be considered a dynamic system. The dynamic system theory based methodology approach systems behaviour through relationships between systems components. Comparing to usual scientific approaches, which try to decompose the analyzed system, this methodology offers a view of entire system behaviour The paper presents a method for building scenarios of wave energy conversion, in the nearshore of the Black Sea, based on a model which includes also forecasts of the weather influence.

On the Further Optimization of the “Green Water Concept” for Wave Energy Conversion

2012 ◽  
Author(s):  
Joop A. Helder ◽  
Christian Schmittner ◽  
Bas Buchner
Keyword(s):  
Energy Conversion ◽  
Wave Energy ◽  
Green Water ◽  
Wave Energy Conversion ◽  
Pilot Model ◽  
Wide Range ◽  
Water Columns ◽  
Relative Water ◽  
Entrapped Air ◽  
The Time Domain

This paper presents initial results from the following-up study of the ‘inverse’ or ‘green water concept’ for wave energy conversion. Initially presented in 2009, the ‘inverse concept’ was developed by MARIN as a vehicle for open discussion and exchange of ideas in the field of wave energy conversion. Pilot model tests presented in 2010 showed the great potential of the concept, but also revealed the challenges associated with Power Take Off design. The present study aims to further optimize the inverse concept. A new PTO system has been incorporated, based on robustness and effective use of the structure’s (de)optimized hull. The resulting renewed concept combines maximized vessel motions with OWC-type of wave energy conversion. This paper focuses on the motion response of the renewed concept. Frequency domain calculations show the response of the concept with water columns (moonpools) at the bow and stern. Remarkably, the already maximized motions of the hull become even more extreme when moonpools are incorporated. Special attention is given to the relative motions of the water inside the moonpools, as these give an indication of the wave energy conversion potential of the concept. The relative water motions inside the moonpools show a large response that is characterized by multiple peaks. This indicates the concept’s ability to convert energy in a wide range of sea states. Results from additional diffraction analysis show that through proper tuning, the water columns inside the moonpools can be modeled as solid water-bodies. This allows for a future numerical modeling of the hydrodynamic interaction between structure, water columns, entrapped air and PTO damping in the time domain.

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