Force in the Connection Line for a Wave Energy Converter: Simulation and Measurement Experimental Setup

2014 ◽  
Author(s):  
Ling Hai ◽  
Olle Svensson ◽  
Valeria Castellucci ◽  
Erik Lejerskog ◽  
Rafael Waters ◽  
...  
Keyword(s):  
Measurement System ◽  
Wave Energy ◽  
Force Measurement ◽  
Hydrodynamic Characteristic ◽  
Wave Climate ◽  
Wave Energy Converter ◽  
Electricity Production ◽  
Energy Converter ◽  
Line Force ◽  
Force Measurement System

In order to capture ocean wave energy and transform it into electric energy, Uppsala University has developed a point absorber wave energy converter (WEC) for electricity production. For a better understanding of a torus shaped buoy’s performance, this paper conducts a force analysis under linear conditions, to investigate the hydrodynamic characteristic and line force differences between the torus buoy that is going to be deployed, and two similar cylindrical buoys. The result reveals the line force from this torus buoy is roughly 5% larger than from cylindrical buoys for the most energy dense wave climate in Lysekil test site, and negative added mass phenomena won’t have a significant impact for the line force. To measure the line force, a force measurement system has been designed. A detailed description is given on the design of the 500 kN force measurement system, and the major differences compared with former force measurement systems. Onshore test result has also been presented. With the force measurement experiment, hydrodynamic analysis for torus buoy can be validated when the system performs linearly, and extreme force for storm weather can be monitored to provide information for future WEC structure’s mechanical design.

Measurement System for Wave Energy Converter: Design and Implementation

2014 ◽  
Author(s):  
Liselotte Lindblad ◽  
Antoine Baudoin ◽  
Mats Leijon
Keyword(s):  
Measurement System ◽  
Wave Energy ◽  
Detection System ◽  
Wave Energy Converter ◽  
Wave Power ◽  
Energy Converter ◽  
Stator Windings ◽  
Lab Experiments ◽  
Line Force ◽  
Converter Design

A Wave Energy Converter (WEC) measurement system has been constructed and installed with the purpose to measure, log and evaluate the WEC’s performance during operation at sea. The WEC is to be deployed at Uppsala University’s wave power research site in Lysekil on the west coast of Sweden. In designing such a system the key research objectives has been (1) to study the risk of overheating due to high currents in the stator windings, (2) to evaluate how the WEC’s outer structure withstands drag and bending forces from the buoy line and (3) to construct a detection system which indicates if water leaks into the generator. The measurement system was designed to collect data essential to study these key objectives. Transducers were used to measure: buoy line force, translator position, phase currents, bending and tensile strain on the generator hull, water level inside generator and the temperature at multiple places inside the generator. The measurement system has been installed and calibrated in the WEC. Furthermore, the design has been evaluated in lab experiments in order to verify the function and accuracy of the different measurements. This paper presents the underlying research objectives for developing the WEC generator measurement system, together with a description of the technical implementation.

scholarly journals Optimizing the Power Take Off of a Wave Energy Converter With Regard to the Wave Climate

2005 ◽  
Vol 128 (1) ◽  
pp. 56-64 ◽  
Author(s):  
Gaelle Duclos ◽  
Aurelien Babarit ◽  
Alain H. Clément
Keyword(s):  
Wave Energy ◽  
Simple Wave ◽  
Wave Climate ◽  
Wave Energy Converter ◽  
Optimal Parameters ◽  
Energy Converter ◽  
Wave Energy Converters ◽  
Classical Wave ◽  
Project Site ◽  
Wave Conditions

Considered as a source of renewable energy, wave is a resource featuring high variability at all time scales. Furthermore wave climate also changes significantly from place to place. Wave energy converters are very often tuned to suit the more frequent significant wave period at the project site. In this paper we show that optimizing the device necessitates accounting for all possible wave conditions weighted by their annual occurrence frequency, as generally given by the classical wave climate scatter diagrams. A generic and very simple wave energy converter is considered here. It is shown how the optimal parameters can be different considering whether all wave conditions are accounted for or not, whether the device is controlled or not, whether the productive motion is limited or not. We also show how they depend on the area where the device is to be deployed, by applying the same method to three sites with very different wave climate.

Evaluation of the annual electricity production of a hybrid breakwater-integrated wave energy converter

Energy ◽  
2020 ◽  
Vol 213 ◽  
pp. 118845
Author(s):  
Tomás Calheiros-Cabral ◽  
Daniel Clemente ◽  
Paulo Rosa-Santos ◽  
Francisco Taveira-Pinto ◽  
Victor Ramos ◽  
...  
Keyword(s):  
Wave Energy ◽  
Wave Energy Converter ◽  
Electricity Production ◽  
Energy Converter

The Effect of the Spectral Distribution of Wave Energy on the Performance of a Bottom Hinged Flap Type Wave Energy Converter

2012 ◽  
Author(s):  
D. Clabby ◽  
A. Henry ◽  
M. Folley ◽  
T. Whittaker
Keyword(s):  
Energy Distribution ◽  
Wave Height ◽  
Wave Energy ◽  
Spectral Distribution ◽  
Energy Production ◽  
Spectral Energy Distribution ◽  
Wave Climate ◽  
Wave Energy Converter ◽  
Spectral Energy ◽  
Energy Converter

The power output from a wave energy converter is typically predicted using experimental and/or numerical modelling techniques. In order to yield meaningful results the relevant characteristics of the device, together with those of the wave climate must be modelled with sufficient accuracy. The wave climate is commonly described using a scatter table of sea states defined according to parameters related to wave height and period. These sea states are traditionally modelled with the spectral distribution of energy defined according to some empirical formulation. Since the response of most wave energy converters vary at different frequencies of excitation, their performance in a particular sea state may be expected to depend on the choice of spectral shape employed rather than simply the spectral parameters. Estimates of energy production may therefore be affected if the spectral distribution of wave energy at the deployment site is not well modelled. Furthermore, validation of the model may be affected by differences between the observed full scale spectral energy distribution and the spectrum used to model it. This paper investigates the sensitivity of the performance of a bottom hinged flap type wave energy converter to the spectral energy distribution of the incident waves. This is investigated experimentally using a 1:20 scale model of Aquamarine Power’s Oyster wave energy converter, a bottom hinged flap type device situated at the European Marine Energy Centre (EMEC) in approximately 13m water depth. The performance of the model is tested in sea states defined according to the same wave height and period parameters but adhering to different spectral energy distributions. The results of these tests show that power capture is reduced with increasing spectral bandwidth. This result is explored with consideration of the spectral response of the device in irregular wave conditions. The implications of this result are discussed in the context of validation of the model against particular prototype data sets and estimation of annual energy production.

Influence of the wave climate seasonality on the performance of a wave energy converter: A case study

Energy ◽  
2017 ◽  
Vol 135 ◽  
pp. 303-316 ◽  
Author(s):  
V. Ramos ◽  
M. López ◽  
F. Taveira-Pinto ◽  
P. Rosa-Santos
Keyword(s):  
Wave Energy ◽  
Wave Climate ◽  
Wave Energy Converter ◽  
Energy Converter

Measurement of the Effect of Power Absorption in the Lee of a Wave Energy Converter

2009 ◽  
Author(s):  
Ian G. C. Ashton ◽  
Lars Johanning ◽  
Brian Linfoot
Keyword(s):  
Wave Field ◽  
Wave Energy ◽  
Ocean Waves ◽  
Wave Climate ◽  
Wave Energy Converter ◽  
Energy Converter ◽  
Wave Measurements ◽  
Temporal And Spatial Variability ◽  
Power Capture ◽  
Local Wave

Monitoring the effect of floating wave energy converter (WEC) devices on the surrounding wave field will be an important tool for monitoring impacts on the local wave climate and coastlines. Measurement will be hampered by the natural variability of ocean waves and the complex response of WEC devices, causing temporal and spatial variability in the effects. Measurements taken during wave tank tests at MARINTEK are used to analyse the effectiveness of point wave measurements at resolving the influence of an array of WEC on the local wave conditions. The variability of waves is measured in front and in the lee of a device, using spectral analysis to identify changes to the incident wave field due to the operating WEC. The power capture and radiation damping are analysed in order to predict the measured changes. Differences in the wave field across the device are clearly observable in the frequency domain. However, they do not unanimously show a reduction in wave energy in the lee of a device and are not well predicted by measured power capture.

scholarly journals A Set-Up of 7 Laser Triangulation Sensors and a Draw-Wire Sensor for Measuring Relative Displacement of a Piston Rod Mechanical Lead-Through Transmission in an Offshore Wave Energy Converter on the Ocean Floor

2012 ◽  
Vol 2012 ◽  
pp. 1-32 ◽  
Author(s):  
E. Strömstedt ◽  
O. Svensson ◽  
M. Leijon
Keyword(s):  
Energy Conversion ◽  
Measurement System ◽  
Wave Energy ◽  
Relative Displacement ◽  
Operating Conditions ◽  
Wave Energy Converter ◽  
Laser Triangulation ◽  
Energy Converter ◽  
Set Up ◽  
Offshore Wave

A concept for offshore wave energy conversion is being developed at the Swedish Centre for Renewable Electric Energy Conversion at Uppsala University in Sweden. The wave energy converter (WEC) in focus contains a piston rod mechanical lead-through transmission for transmitting the absorbed mechanical wave energy through the generator capsule wall while preventing seawater from entering the capsule. A set-up of 7 laser triangulation sensors has been installed inside the WEC to measure relative displacement of the piston rod and its corresponding seal housing. A draw-wire sensor has also been set up to measure translator position and the axial displacement of the piston rod. The paper gives a brief introduction to the Lysekil research site, the WEC concept, and the direct drive of WEC prototype L2. A model of operation for the piston rod mechanical lead-through transmission is given. The paper presents sensor choice, configuration, adaptation, mounting, and measurement system calibration along with a description of the data acquisition system. Results from 60 s measurements of nominal operation two months apart with centered moving averages are presented. Uncertainty and error estimations with statistical analyses and signal-to-noise ratios are presented. Conclusions are drawn on the relative motions of the piston rod and the seal housing under normal operating conditions, and an assessment of the applicability of the measurement system is made.

scholarly journals Hydraulic and Structural Assessment of a Rubble-Mound Breakwater with a Hybrid Wave Energy Converter

2021 ◽  
Vol 9 (9) ◽  
pp. 922
Author(s):  
Daniel Clemente ◽  
Tomás Calheiros-Cabral ◽  
Paulo Rosa-Santos ◽  
Francisco Taveira-Pinto
Keyword(s):  
Stability Analysis ◽  
Wave Energy ◽  
Ocean Waves ◽  
Wave Climate ◽  
Wave Energy Converter ◽  
Scale Model ◽  
Hybrid Wave ◽  
Energy Converter ◽  
The North ◽  
Rubble Mound

Seaports’ breakwaters serve as important infrastructures capable of sheltering ships, facilities, and harbour personnel from severe wave climate. Given their exposure to ocean waves and port authorities’ increasing awareness towards sustainability, it is important to develop and assess wave energy conversion technologies suitable of being integrated into seaport breakwaters. To fulfil this goal whilst ensuring adequate sheltering conditions, this paper describes the performance and stability analysis of the armour layer and toe berm of a 1/50 geometric scale model of the north breakwater extension project, intended for the Port of Leixões, with an integrated hybrid wave energy converter. This novel hybrid concept combines an oscillating water column and an overtopping device. The breakwater was also studied without the hybrid wave energy device as to enable a thorough comparison between both solutions regarding structural stability, safety, and overtopping performance. The results point towards a considerable reduction in the overtopping volumes through the integration of the hybrid technology by an average value of 50%, while the stability analysis suggests that the toe berm of the breakwater is not significantly affected by the hybrid device, leading to acceptable safety levels. Even so, some block displacements were observed, and the attained stability numbers were slightly above the recommended thresholds from the literature. It is also shown that traditional damage assessment parameters should be applied with care when non-conventional structures are analysed, such as rubble-mound breakwaters with integrated wave energy converters.

scholarly journals A Power Take-Off and Control Strategy in a Test Wave Energy Converter for a Moderate Wave Climate

2016 ◽  
pp. 478-483
Author(s):  
K.L. De Koker ◽  
G. Crevecoeur ◽  
B. Meersman ◽  
M. Vantorre ◽  
L. Vandevelde
Keyword(s):  
Wave Energy ◽  
Control Strategy ◽  
Wave Climate ◽  
Wave Energy Converter ◽  
Energy Converter ◽  
And Control
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