Статті в журналах з теми "WEC Sea"
Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: WEC Sea.
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 статей у журналах для дослідження на тему "WEC Sea".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте статті в журналах для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
Verao Fernandez, Gael, Vasiliki Stratigaki, Panagiotis Vasarmidis, Philip Balitsky, and Peter Troch. "Wake Effect Assessment in Long- and Short-Crested Seas of Heaving-Point Absorber and Oscillating Wave Surge WEC Arrays." Water 11, no. 6 (May 29, 2019): 1126. http://dx.doi.org/10.3390/w11061126.
Повний текст джерелаАнотація:
In the recent years, the potential impact of wave energy converter (WEC) arrays on the surrounding wave field has been studied using both phase-averaging and phase-resolving wave propagation models. Obtaining understanding of this impact is important because it may affect other users in the sea or on the coastline. However, in these models a parametrization of the WEC power absorption is often adopted. This may lead to an overestimation or underestimation of the overall WEC array power absorption, and thus to an unrealistic estimation of the potential WEC array impact. WEC array power absorption is a result of energy extraction from the incoming waves, and thus wave height decrease is generally observed downwave at large distances (the so-called “wake” or “far-field” effects). Moreover, the power absorption depends on the mutual interactions between the WECs of an array (the so-called “near field” effects). To deal with the limitations posed by wave propagation models, coupled models of recent years, which are nesting wave-structure interaction solvers into wave propagation models, have been used. Wave-structure interaction solvers can generally provide detailed hydrodynamic information around the WECs and a more realistic representation of wave power absorption. Coupled models have shown a lower WEC array impact in terms of wake effects compared to wave propagation models. However, all studies to date in which coupled models are employed have been performed using idealized long-crested waves. Ocean waves propagate with a certain directional spreading that affects the redistribution of wave energy in the lee of WEC arrays, and thus gaining insight wake effect for irregular short-crested sea states is crucial. In our research, a new methodology is introduced for the assessment of WEC array wake effects for realistic sea states. A coupled model is developed between the wave-structure interaction solver NEMOH and the wave propagation model MILDwave. A parametric study is performed showing a comparison between WEC array wake effects for regular, long-crested irregular, and short-crested irregular waves. For this investigation, a nine heaving-point absorber array is used for which the wave height reduction is found to be up to 8% lower at 1.0 km downwave the WEC array when changing from long-crested to short-crested irregular waves. Also, an oscillating wave surge WEC array is simulated and the overestimation of the wake effects in this case is up to 5%. These differences in wake effects between different wave types indicates the need to consider short-crested irregular waves to avoid overestimating the WEC array potential impacts. The MILDwave-NEMOH coupled model has proven to be a reliable numerical tool, with an efficient computational effort for simulating the wake effects of two different WEC arrays under the action of a range of different sea states.
2
Castellucci, Valeria, and Erland Strömstedt. "Sea level variability in the Swedish Exclusive Economic Zone and adjacent seawaters: influence on a point absorbing wave energy converter." Ocean Science 15, no. 6 (November 19, 2019): 1517–29. http://dx.doi.org/10.5194/os-15-1517-2019.
Повний текст джерелаАнотація:
Abstract. Low-frequency sea level variability can be a critical factor for several wave energy converter (WEC) systems, for instance, linear systems with a limited stroke length. Consequently, when investigating suitable areas for deployment of those WEC systems, sea level variability should be taken into account. In order to facilitate wave energy developers finding the most suitable areas for wave energy park installations, this paper describes a study that gives them additional information by exploring the annual and monthly variability of the sea level in the Baltic Sea and adjacent seawaters, with a focus on the Swedish Exclusive Economic Zone. Overall, 10 years of reanalysis data from the Copernicus project have been used to conduct this investigation. The results are presented by means of maps showing the maximum range and the standard deviation of the sea level with a horizontal spatial resolution of about 1 km. A case study illustrates how the results can be used by the WEC developers to limit the energy absorption loss of their devices due to sea level variation. Depending on the WEC technology one wants to examine, the results lead to different conclusions. For the Uppsala point absorber L12 and the sea state considered in the case study, the most suitable sites where to deploy WEC parks from a sea level variation viewpoint are found in the Gotland basins and in the Bothnian Sea, where the energy loss due to sea level variations is negligible.
3
Troch, Peter, Charlotte Beels, Julien De Rouck, and Griet De Backer. "WAKE EFFECTS BEHIND A FARM OF WAVE ENERGY CONVERTERS FOR IRREGULAR LONG-CRESTED AND SHORT-CRESTED WAVES." Coastal Engineering Proceedings 1, no. 32 (February 1, 2011): 53. http://dx.doi.org/10.9753/icce.v32.waves.53.
Повний текст джерелаАнотація:
The contribution of wave energy to the renewable energy supply is rising. To extract a considerable amount of wave power, Wave Energy Converters (WECs) are arranged in several rows or in a ’farm’. WECs in a farm are interacting (e.g. the presence of other WECs influence the operational behaviour of a single WEC) and the overall power absorption is affected. In this paper wake effects in the lee of a single WEC and multiple WECs of the overtopping type, where the water volume of overtopped waves is first captured in a basin above mean sea level and then drains back to the sea through hydro turbines, are studied using the time-dependent mild-slope equation model MILDwave. The wake behind a single WEC is investigated for long-crested and short-crested incident waves. The wake becomes wider for larger wave peak periods. An increasing directional spreading results in a faster wave regeneration and a shorter wake behind the WEC. The wake in the lee of multiple WECs is calculated for two different farm lay-outs, i.e. an aligned grid and a staggered grid, with varying lateral and longitudinal spacing. The wave power redistribution in and behind each farm lay-out is studied in detail using MILDwave. In general, the staggered grid results in the highest overall wave power absorption.
4
Wan, Zhanhong, Ze Li, Dahai Zhang, and Honghao Zheng. "Design and Research of Slope-Pendulum Wave Energy Conversion Device." Journal of Marine Science and Engineering 10, no. 11 (October 24, 2022): 1572. http://dx.doi.org/10.3390/jmse10111572.
Повний текст джерелаАнотація:
Wave energy is a kind of clean energy that is rich in reserves and has not been exploited on a large scale. The slope-pendulum wave energy conversion (S-PWEC) device has been optimized in structure and its capture efficiency has been increased. Taking the selection of the Zhejiang sea area as the research background, this paper performs numerical simulation and array WEC experimental testing of S-PWEC under 66 major sea conditions. The experimental results show that S-PWEC adds a slope structure to the bottom, which can effectively improve the motion response ability and resistance to extreme sea conditions. In the regular wave and irregular wave tests, the electron power output efficiency can be increased by 13.24% and 10.06%, respectively; in the array WEC experiment, the diffraction effect and radiation effect will affect the work of the array WEC, and the optimal arrangement distance can be selected to maximize the power output of the WEC system.
5
Vervaet, Timothy, Vasiliki Stratigaki, Brecht De Backer, Kurt Stockman, Marc Vantorre, and Peter Troch. "Experimental Modelling of Point-Absorber Wave Energy Converter Arrays: A Comprehensive Review, Identification of Research Gaps and Design of the WECfarm Setup." Journal of Marine Science and Engineering 10, no. 8 (August 2, 2022): 1062. http://dx.doi.org/10.3390/jmse10081062.
Повний текст джерелаАнотація:
Commercial wave energy exploitation will be realised by placing multiple wave energy converters (WECs) in an array configuration. A point-absorber WEC consists of a floating or submerged body to capture wave energy from different wave directions. This point-absorber WEC acts as an efficient wave absorber that is also an efficient wave generator. Optimising the WEC array layout to obtain constructive interference within the WEC array is theoretically beneficial, whereas for wind farms, it is only important to avoid destructive interference within an array of wind turbines due to wake effects. Moreover, the WEC array layout should be optimised simultaneously with the applied control strategy. This article provides a literature review on the state of the art in physical modelling of point-absorber WEC arrays and the identification of research gaps. To cover the scientific gap of experimental data necessary for the validation of recently developed (nonlinear) numerical models for WEC arrays, Ghent University has introduced the “WECfarm” project. The identified research gaps are translated into design requirements for the “WECfarm” WEC array setup and test matrix. This article presents the design of the “WECfarm” experimental setup, consisting of an array of five generic heaving point-absorber WECs. The WECs are equipped with a permanent magnet synchronous motor (PMSM), addressing the need for WEC array tests with an accurate and actively controllable power take-off (PTO). The WEC array control and data acquisition are realised with a Speedgoat Performance real-time target machine, offering the possibility to implement advanced WEC array control strategies in the MATLAB-Simulink model. Wave basin testing includes long- and short-crested waves and extreme wave conditions, representing real sea conditions. Within the “WECfarm” project, two experimental campaigns were performed at the Aalborg University wave basin: (a) a testing of the first WEC in April 2021 and (b) a testing of a two-WEC array in February 2022. An experimental campaign with a five-WEC array is under preparation at the moment of writing.
6
Zhang, Bo, Haixu Zhang, Sheng Yang, Shiyu Chen, Xiaoshan Bai, and Awais Khan. "Predictive Control for a Wave-Energy Converter Array Based on an Interconnected Model." Journal of Marine Science and Engineering 10, no. 8 (July 27, 2022): 1033. http://dx.doi.org/10.3390/jmse10081033.
Повний текст джерелаАнотація:
This paper proposes a model predictive control (MPC) method based on an interconnected model to maximize the ocean wave energy extracted by a wave-energy converter (WEC) array. In the proposed method, a formally uniform interconnected model is applied to represent the dynamics of an array consisting of an arbitrary quantity of WECs, simultaneously considering the hydrodynamic interaction among all the WEC devices. First, the WEC devices and their hydrodynamic interaction are represented in an interconnected model that describes the networked dynamics of a variety of WEC arrays with distinct spatial geometry layout of the WEC devices deployed in the sea field. Second, based on the presented model, an MPC method is applied to achieve the coordinated control of the WEC array to improve its energy conversion efficiency under the constraints of buoy position and control force. Third, a hardware-in-the-loop (HIL) platform is developed to simulate the WEC array’s physical operating conditions, and the proposed method is implemented on the platform to test its performance. The test results show that the proposed MPC method using the interconnected model has a higher energy harvesting efficiency than the classic MPC method.
7
Thomas, Simon, Mikael Eriksson, Malin Göteman, Martyn Hann, Jan Isberg, and Jens Engström. "Experimental and Numerical Collaborative Latching Control of Wave Energy Converter Arrays." Energies 11, no. 11 (November 5, 2018): 3036. http://dx.doi.org/10.3390/en11113036.
Повний текст джерелаАнотація:
A challenge while applying latching control on a wave energy converter (WEC) is to find a reliable and robust control strategy working in irregular waves and handling the non-ideal behavior of real WECs. In this paper, a robust and model-free collaborative learning approach for latchable WECs in an array is presented. A machine learning algorithm with a shallow artificial neural network (ANN) is used to find optimal latching times. The applied strategy is compared to a latching time that is linearly correlated with the mean wave period: It is remarkable that the ANN-based WEC achieved a similar power absorption as the WEC applying a linear latching time, by applying only two different latching times. The strategy was tested in a numerical simulation, where for some sea states it absorbed more than twice the power compared to the uncontrolled WEC and over 30% more power than a WEC with constant latching. In wave tank tests with a 1:10 physical scale model the advantage decreased to +3% compared to the best tested constant latching WEC, which is explained by the lower advantage of the latching strategy caused by the non-ideal latching of the physical power take-off model.
8
Forbush, Dominic Dean, Giorgio Bacelli, Steven J. Spencer, Ryan G. Coe, David G. Wilson, and Bryson Robertson. "Self-Tuning WEC Controller for Changing Sea States." International Marine Energy Journal 5, no. 3 (December 19, 2022): 327–38. http://dx.doi.org/10.36688/imej.5.327-338.
Повний текст джерелаАнотація:
A self-tuning proportional-integral control law prescribingmotor torques was tested in experiment on a threedegree-of-freedom wave energy converter. The control objectivewas to maximize electrical power. The control law relied uponan identified model of device intrinsic impedance to generate afrequency-domain estimate of the wave-induced excitation forceand measurements of device velocities. The control law was testedin irregular sea-states that evolved over hours (a rapid, butrealistic time-scale) and that changed instantly (an unrealisticscenario to evaluate controller response). For both cases, thecontroller converges to gains that closely approximate the postcalculatedoptimal gains for all degrees of freedom in a sufficientlyshort-time for realistic sea states. In addition, electricalpower was found to be relatively insensitive to gain tuning overa broad range of gains, implying that an imperfectly tunedcontroller does not result in a large penalty to electrical powercapture. Because the controller relies on an identified model ofdevice intrinsic impedance, the sensitivity of power capture wasevaluated with respect to uncertainty in the constituent termsof intrinsic impedance. Power capture is found to be relativelyinsensitive to uncertainty of 20% in constituent terms of theidentified intrinsic impedance model. An extension of this controllaw that allows for adaptation to a changing device impedancemodel over time is proposed for long-term deployments, aswell as an approach to explicitly handle constraints within thisarchitecture.
9
Boo, Sung Youn, and Steffen Allan Shelley. "Design and Analysis of a Mooring Buoy for a Floating Arrayed WEC Platform." Processes 9, no. 8 (August 10, 2021): 1390. http://dx.doi.org/10.3390/pr9081390.
Повний текст джерелаАнотація:
This paper presents the design and analysis of a mooring buoy and its mooring systems to moor a floating platform mounting an arrayed Wave Energy Converters (WECs). The mooring buoy allows the WEC platform to weathervane around the mooring buoy freely by the prevailing environment directions, which enables consistent power generation. The WEC platform is connected to the buoy with synthetic hawsers, while station-keeping of the buoy is maintained with catenary mooring lines of chains tied to the buoy keel. The buoy also accommodates a power cable to transfer the electricity from the WEC platform to the shore. The WEC platform is designed to produce a total of 1.0 MW with multiple WECs installed in an array. Fully coupled time-domain analyses are conducted under the site sea states, including extreme 50 y and survival 100 y conditions. The buoy motions, mooring tensions and other design parameters are evaluated. Strength and fatigue designs of the mooring systems are validated with requirements according to industry standards. Global and local structural designs of the mooring buoy are carried out and confirm the design compliances.
10
Yu, Long Fei, and Liang Sheng Zhu. "Hydrodynamic Response of Wave Energy Converters under Complex Sea State." Applied Mechanics and Materials 501-504 (January 2014): 1919–26. http://dx.doi.org/10.4028/www.scientific.net/amm.501-504.1919.
Повний текст джерелаАнотація:
In real sea state, Ocean energy devices to work hard to stabilize, or even destroyed. Based on Airy wave theory, Movement and force of heaving cylindrical wave-energy converter (WEC) was analyzed under the complex marine state. Then setting the South China coast as the environmental background, and simulating and computing the motion response of the buoy and the mooring system under various sea conditions. The computational data show that complex mechanical response was happened and the mooring system (SM) has excellent mooring performance. The research results have practical significance for heaving cylindrical WEC survival design under real sea conditions.
11
Marrec, P., T. Cariou, E. Macé, P. Morin, L. A. Salt, M. Vernet, B. Taylor, K. Paxman, and Y. Bozec. "Dynamics of air–sea CO<sub>2</sub> fluxes in the northwestern European shelf based on voluntary observing ship and satellite observations." Biogeosciences 12, no. 18 (September 18, 2015): 5371–91. http://dx.doi.org/10.5194/bg-12-5371-2015.
Повний текст джерелаАнотація:
Abstract. From January 2011 to December 2013, we constructed a comprehensive pCO2 data set based on voluntary observing ship (VOS) measurements in the western English Channel (WEC). We subsequently estimated surface pCO2 and air–sea CO2 fluxes in northwestern European continental shelf waters using multiple linear regressions (MLRs) from remotely sensed sea surface temperature (SST), chlorophyll a concentration (Chl a), wind speed (WND), photosynthetically active radiation (PAR) and modeled mixed layer depth (MLD). We developed specific MLRs for the seasonally stratified northern WEC (nWEC) and the permanently well-mixed southern WEC (sWEC) and calculated surface pCO2 with uncertainties of 17 and 16 μatm, respectively. We extrapolated the relationships obtained for the WEC based on the 2011–2013 data set (1) temporally over a decade and (2) spatially in the adjacent Celtic and Irish seas (CS and IS), two regions which exhibit hydrographical and biogeochemical characteristics similar to those of WEC waters. We validated these extrapolations with pCO2 data from the SOCAT and LDEO databases and obtained good agreement between modeled and observed data. On an annual scale, seasonally stratified systems acted as a sink of CO2 from the atmosphere of −0.6 ± 0.3, −0.9 ± 0.3 and −0.5 ± 0.3 mol C m−2 yr−1 in the northern Celtic Sea, southern Celtic sea and nWEC, respectively, whereas permanently well-mixed systems acted as source of CO2 to the atmosphere of 0.2 ± 0.2 and 0.3 ± 0.2 mol C m−2 yr−1 in the sWEC and IS, respectively. Air–sea CO2 fluxes showed important inter-annual variability resulting in significant differences in the intensity and/or direction of annual fluxes. We scaled the mean annual fluxes over these provinces for the last decade and obtained the first annual average uptake of −1.11 ± 0.32 Tg C yr−1 for this part of the northwestern European continental shelf. Our study showed that combining VOS data with satellite observations can be a powerful tool to estimate and extrapolate air–sea CO2 fluxes in sparsely sampled area.
12
Davidson, Josh, and Tamás Kalmár-Nagy. "A Real-Time Detection System for the Onset of Parametric Resonance in Wave Energy Converters." Journal of Marine Science and Engineering 8, no. 10 (October 20, 2020): 819. http://dx.doi.org/10.3390/jmse8100819.
Повний текст джерелаАнотація:
Parametric resonance is a dynamic instability due to the internal transfer of energy between degrees of freedom. Parametric resonance is known to cause large unstable pitch and/or roll motions in floating bodies, and has been observed in wave energy converters (WECs). The occurrence of parametric resonance can be highly detrimental to the performance of a WEC, since the energy in the primary mode of motion is parasitically transferred into other modes, reducing the available energy for conversion. In addition, the large unstable oscillations produce increased loading on the WEC structure and mooring system, accelerating fatigue and damage to the system. To remedy the negative effects of parametric resonance on WECs, control systems can be designed to mitigate the onset of parametric resonance. A key element of such a control system is a real-time detection system, which can provide an early warning of the likely occurrence of parametric resonance, enabling the control system sufficient time to respond and take action to avert the impending exponential increase in oscillation amplitude. This paper presents the first application of a real-time detection system for the onset of parametric resonance in WECs. The method is based on periodically assessing the stability of a mathematical model for the WEC dynamics, whose parameters are adapted online, via a recursive least squares algorithm, based on online measurements of the WEC motion. The performance of the detection system is demonstrated through a case study, considering a generic cylinder type spar-buoy, a representative of a heaving point absorber WEC, in both monochromatic and polychromatic sea states. The detection system achieved 95% accuracy across nearly 7000 sea states, producing 0.4% false negatives and 4.6% false positives. For the monochromatic waves more than 99% of the detections occurred while the pitch amplitude was less than 1/6 of its maximum amplitude, whereas for the polychromatic waves 63% of the detections occurred while the pitch amplitude was less than 1/6 of its maximum amplitude and 91% while it was less than 1/3 of its maximum amplitude.
13
Forbush, Dominic D., Giorgio Bacelli, Steven J. Spencer, and Ryan G. Coe. "A Self-Tuning WEC Controller For Changing Sea States." IFAC-PapersOnLine 53, no. 2 (2020): 12307–12. http://dx.doi.org/10.1016/j.ifacol.2020.12.1185.
Повний текст джерела
14
Leary, Matthew, Curtis Rusch, Zhe Zhang, and Bryson Robertson. "Comparison and Validation of Hydrodynamic Theories for Wave Energy Converter Modelling." Energies 14, no. 13 (July 1, 2021): 3959. http://dx.doi.org/10.3390/en14133959.
Повний текст джерелаАнотація:
Dynamic Wave Energy Converter (WEC) models utilize a wide variety of fundamental hydrodynamic theories. When incorporating novel hydrodynamic theories into numerical models, there are distinct impacts on WEC rigid body motions, cable dynamics, and final power production. This paper focuses on developing an understanding of the influence several refined hydrodynamic theories have on WEC dynamics, including weakly nonlinear Froude-Krylov and hydrostatic forces, body-to-body interactions, and dynamic cable modelling. All theories have evolved from simpler approaches and are of importance to a wide array of WEC archetypes. This study quantifies the impact these theories have on modelling accuracy through a WEC case study. Theoretical differences are first explored in a regular sea state. Subsequently, numerical validation efforts are performed against field data following wave reconstruction techniques. Comparisons of significance are WEC motion and cable tension. It is shown that weakly nonlinear Froude-Krylov and hydrostatic force calculations and dynamic cable modelling both significantly improve simulated WEC dynamics. However, body-to-body interactions are not found to impact simulated WEC dynamics.
15
Ren, Nianxin, Yuekai Yu, Xiang Li, and Jinping Ou. "Hydrodynamic Analysis of a Modular Integrated Floating Structure System Based on Dolphin-Fender Mooring." Journal of Marine Science and Engineering 10, no. 10 (October 10, 2022): 1470. http://dx.doi.org/10.3390/jmse10101470.
Повний текст джерелаАнотація:
For both the expansion of important islands/reefs and the development of marine resources in South China Sea, a modular integrated floating structure (MIFS) system with tidal self-adaptation dolphin-fender mooring (DFM) has been proposed. The DFM, coupled with wave energy converters (WEC), can serve as an anti-motion system. Considering both the modules’ hydrodynamic interaction effect and the connectors’ mechanical coupling effect, both dynamic responses of the MIFS system and the WEC’s output power characteristics were investigated under typical sea conditions. Based on the comprehensive consideration of key factors (safety, economy, and comfort), the effects of both the DFM and module connectors were systematically studied for the MIFS system. Preliminarily optimal design parameters of corresponding connectors and WECs were suggested. The security of the MIFS system under extreme sea conditions was checked, and a promising survival strategy has been proposed. In addition, the modular expansion scheme of the MIFS system was further discussed, and the results indicated that the proposed MIFS system shows good expansibility. The WEC can not only improve both dynamic responses and the comfort of inner modules, but also make considerable wave energy contributions.
16
Hong, Yue, Irina Temiz, Jianfei Pan, Mikael Eriksson, and Cecilia Boström. "Damping Studies on PMLG-Based Wave Energy Converter under Oceanic Wave Climates." Energies 14, no. 4 (February 9, 2021): 920. http://dx.doi.org/10.3390/en14040920.
Повний текст джерелаАнотація:
Wave energy converters (WECs), which are designed to harvest ocean wave energy, have recently been improved by the installation of numerous conversion mechanisms; however, it is still difficult to find an appropriate method that can compromise between strong environmental impact and robust performance by transforming irregular wave energy into stable electrical power. To solve this problem, an investigation into the impact of varied wave conditions on the dynamics of WECs and to determine an optimal factor for WECs to comply with long-term impacts was performed. In this work, we researched the performance of WECs influenced by wave climates. We used a permanent magnet linear generator (PMLG)-based WEC that was invented at Uppsala University. The damping effect was first studied with a PMLG-type WEC. Then, a group of sea states was selected to investigate their impact on the power production of the WEC. Two research sites were chosen to investigate the WEC’s annual energy production as well as a study on the optimal damping coefficient impact. In addition, we compared the WEC’s energy production between optimal damping and constant damping under a full range of sea states at both sites. Our results show that there is an optimal damping coefficient that can achieve the WEC’s maximum power output. For the chosen research sites, only a few optimal damping coefficients were able to contribute over 90% of the WEC’s annual energy production. In light of the comparison between optimal and constant damping, we conclude that, for specific regions, constant damping might be a better choice for WECs to optimize long-term energy production.
17
Stratigaki, Vasiliki, Peter Troch, Timothy Stallard, Jens Peter Kofoed, Michel Benoit, Giovanni Mattarollo, Aurelien Babarit, David Forehand, and Matthew Folley. "LARGE SCALE EXPERIMENTS ON FARMS OF HEAVING BUOYS TO INVESTIGATE WAKE DIMENSIONS, NEAR-FIELD AND FAR-FIELD EFFECTS." Coastal Engineering Proceedings 1, no. 33 (December 15, 2012): 71. http://dx.doi.org/10.9753/icce.v33.management.71.
Повний текст джерелаАнотація:
The shrinking reserves of fossil fuels in combination with the increasing energy demand have enhanced the interest in renewable energy sources, including wave energy. In order to extract a considerable amount of wave power, large numbers of Wave Energy Converters will have to be arranged in arrays or farms using a particular geometrical layout. The operational behaviour of a single device may have a positive or negative effect on the power absorption of the neighbouring WECs in the farm (near-field effects). Moreover, as a result of the interaction between the WECs within a farm, the overall power absorption and the wave climate in the lee of the WECs is modified, which may influence neighbouring farms, other users in the sea or even the coastline (far-field effects). Several numerical studies on large WEC arrays have already been performed, but large scale experimental studies on near-field and far-field wake effects of large WEC arrays are not available in literature. Within the HYDRALAB IV European programme, the research project WECwakes has been introduced to perform large scale experiments in the Shallow Water Wave Basin of DHI, in Denmark, on large arrays of point absorbers for different layout configurations and inter-WEC spacings. The aim is to validate and further develop the applied numerical methods, as well as to optimize the geometrical layout of WEC arrays for real applications.
18
Zhai, Qiang, Linsen Zhu, and Shizhou Lu. "Life Cycle Assessment of a Buoy-Rope-Drum Wave Energy Converter." Energies 11, no. 9 (September 13, 2018): 2432. http://dx.doi.org/10.3390/en11092432.
Повний текст джерелаАнотація:
This study presents a life cycle assessment (LCA) study for a buoy-rope-drum (BRD) wave energy converter (WEC), so as to understand the environmental performance of the BRD WEC by eco-labeling its life cycle stages and processes. The BRD WEC was developed by a research group at Shandong University (Weihai). The WEC consists of three main functional modules including buoy, generator and mooring modules. The designed rated power capacity is 10 kW. The LCA modeling is based on data collected from actual design, prototype manufacturing, installation and onsite sea test. Life cycle inventory (LCI) analysis and life cycle impact analysis (LCIA) were conducted. The analyses show that the most significant environmental impact contributor is identified to be the manufacturing stage of the BRD WEC due to consumption of energy and materials. Potential improvement approaches are proposed in the discussion. The LCI and LCIA assessment results are then benchmarked with results from reported LCA studies of other WECs, tidal energy converters, as well as offshore wind and solar PV systems. This study presents the energy and carbon intensities and paybacks with 387 kJ/kWh, 89 gCO2/kWh, 26 months and 23 months respectively. The results show that the energy and carbon intensities of the BRD WEC are slightly larger than, however comparable, in comparison with the referenced WECs, tidal, offshore wind and solar PV systems. A sensitivity analysis was carried out by varying the capacity factor from 20–50%. The energy and carbon intensities could reach as much as 968 kJ/kWh and 222 gCO2/kWh respectively while the capacity factor decreasing to 20%. Limitations for this study and scope of future work are discussed in the conclusion.
19
Konispoliatis, Dimitrios N., and Spyridon A. Mavrakos. "Hydrodynamic Efficiency of a Wave Energy Converter in Front of an Orthogonal Breakwater." Journal of Marine Science and Engineering 9, no. 1 (January 17, 2021): 94. http://dx.doi.org/10.3390/jmse9010094.
Повний текст джерелаАнотація:
In the present study, the hydrodynamic efficiency of a cylindrical wave energy converter (WEC) of vertical symmetry axis and arranged in front of a reflecting orthogonal breakwater is explored. The idea is based on exploiting the anticipated amplification of the scattered and the reflected wave fields originating from the presence of the vertical walls, towards increasing the WEC’s wave power absorption due to the walls’ wave reflections. Two types of converters are examined, namely the heaving device and the oscillating water column (OWC) device, assuming linear potential theory. The associated diffraction-, motion-, and pressure-radiation problems are solved using axisymmetric eigenfunction expansions for the velocity potential around the WECs by properly accounting for the wave field’s modification due to the walls’ presence. To this end, a theoretical formulation dealing with the evaluation of the converter’s performance is presented accounting for the coupling between the WEC and the reflecting vertical walls. The results depict that the amount of the harvested wave power by the WEC in front of an orthogonal wall is amplified compared to the absorbed wave power by the same WEC in the open sea.
20
Jabrali, A., R. Khatyr, and J. Khalid Naciri. "Parameters variation effects on energy recovery for a freely floating wave energy converter." MATEC Web of Conferences 286 (2019): 09002. http://dx.doi.org/10.1051/matecconf/201928609002.
Повний текст джерелаАнотація:
This study presents the effects of parameters variations on the recovered energy for a floating wave energy converter (WEC) device. The articulated multi body floating WEC under consideration consists of two cylinders connected by a flat plate. The connections between the parts of the WEC allow the rotational movements of cylinders and the plate. The aim of this paper is to investigate the coupled effect of the length of the plate with the amplitude and period of the wave on the recovered energy by the floating WEC. The results show that the value of the optimum length for the plate is related to the sea wave condition, and more particularly to the amplitude and wavelength of the oscillations of the free surface.
21
Ticona Rollano, Fadia, Thanh Toan Tran, Yi-Hsiang Yu, Gabriel García-Medina, and Zhaoqing Yang. "Influence of Time and Frequency Domain Wave Forcing on the Power Estimation of a Wave Energy Converter Array." Journal of Marine Science and Engineering 8, no. 3 (March 4, 2020): 171. http://dx.doi.org/10.3390/jmse8030171.
Повний текст джерелаАнотація:
Industry-specific tools for analyzing and optimizing the design of wave energy converters (WECs) and associated power systems are essential to advancing marine renewable energy. This study aims to quantify the influence of phase information on the device power output of a virtual WEC array. We run the phase-resolving wave model FUNWAVE-TVD (Total Variation Diminishing) to generate directional waves at the PacWave South site offshore from Newport, Oregon, where future WECs are expected to be installed for testing. The two broad cases presented correspond to mean wave climates during warm months (March–August) and cold months (September–February). FUNWAVE-TVD time series of sea-surface elevation are then used in WEC-Sim, a time domain numerical model, to simulate the hydrodynamic response of each device in the array and estimate their power output. For comparison, WEC-Sim is also run with wave energy spectra calculated from the FUNWAVE-TVD simulations, which do not retain phase information, and with wave spectra computed using the phase-averaged model Simulating WAves Nearshore (SWAN). The use of spectral data in WEC-Sim requires a conversion from frequency to time domain by means of random superposition of wave components, which are not necessarily consistent because of the linear assumption implicit in this method. Thus, power response is characterized by multiple realizations of the wave climates.
22
Zou, Shangyan, and Ossama Abdelkhalik. "A Numerical Simulation of a Variable-Shape Buoy Wave Energy Converter." Journal of Marine Science and Engineering 9, no. 6 (June 4, 2021): 625. http://dx.doi.org/10.3390/jmse9060625.
Повний текст джерелаАнотація:
Wave energy converters (WECs) usually require reactive power for increased levels of energy conversion, resulting in the need for more complex power take-off (PTO) units, compared to WECs that do not require reactive power. A WEC without reactive power produces much less energy, though. The concept of Variable Shape Buoy Wave Energy Converters (VSB WECs) is proposed to allow continuous shape-change aiming at eliminating the need for reactive power, while converting power at a high level. The proposed concept involves complex and nonlinear interactions between the device and the waves. This paper presents a Computational Fluid Dynamics (CFD) tool that is set up to simulate VSB WECs, using the ANSYS 2-way fluid–structure interaction (FSI) tool. The dynamic behavior of a VSB WEC is simulated in this CFD-based Numerical Wave Tank (CNWT), in open sea conditions. The simulation results show that the tested device undergoes a significant deformation in response to the incoming waves, before it reaches a steady-state behavior. This is in agreement with a low-fidelity dynamic model developed in earlier work. The resulting motion is significantly different from the motion of a rigid body WEC. The difference in the motion can be leveraged for better energy capture without the need for reactive power.
23
Agyekum, Ephraim Bonah, Seepana PraveenKumar, Aleksei Eliseev, and Vladimir Ivanovich Velkin. "Design and Construction of a Novel Simple and Low-Cost Test Bench Point-Absorber Wave Energy Converter Emulator System." Inventions 6, no. 1 (March 22, 2021): 20. http://dx.doi.org/10.3390/inventions6010020.
Повний текст джерелаАнотація:
This paper proposed a test bench device to emulate or simulate the electrical impulses of a wave energy converter (WEC). The objective of the study is to reconstruct under laboratory conditions the dynamics of a WEC in the form of an emulator to assess the performance, which, in this case, is the output power. The designed emulator device is programmable, which makes it possible to create under laboratory conditions the operating mode of the wave generator, identical to how the wave generator would work under real sea conditions. Any control algorithm can be executed in the designed emulator. In order to test the performance of the constructed WEC emulator, an experiment was conducted to test its power output against that of a real point-absorber WEC. The results indicate that, although the power output for that of the real WEC was higher than the WEC emulator, the emulator performed perfectly well. The relatively low power output of the emulator was because of the type of algorithm that was written for the emulator, therefore increasing the speed of the motor in the algorithm (code) would result in higher output for the proposed WEC emulator.
24
Sun, Shang, Luo, Lu, Wu, and Zhu. "Using Flexible Blades to Improve the Performance of Novel Small-Scale Counter-Rotating Self-Adaptable Wave Energy Converter for Unmanned Marine Equipment." Journal of Marine Science and Engineering 7, no. 7 (July 15, 2019): 223. http://dx.doi.org/10.3390/jmse7070223.
Повний текст джерелаАнотація:
Unmanned marine equipment has been increasingly developed for open seas. The lack of efficient and reliable power supply is currently one of the bottlenecks restricting the practical application of these devices. In order to provide a viable power supply method for unmanned marine equipment, such as sonic buoys and sea robots, we originally propose a novel small-scale flexible blade wave energy converter (WEC) based on self-adaptable counter-rotating operation mechanism. The flexible blade WEC is designed on the basis of the rigid blade WEC with the caging device. This paper identifies the key factors affecting WEC performance through theoretical analysis. According to the numerical simulation analysis, the output mechanical power of the double-layer absorber is 12.8 W, and the hydraulic efficiency is 36.3%. The results of the verification experiment show that the peak power of WEC is 5.8 W and the average power is 3.2 W. The WEC with 65Mn flexible blade under most experimental conditions has the best performance when the blade thickness is 0.10 mm. The study shows that the new generation WEC can effectively overcome the excessive fluctuation of the output power of the previous generation WEC. The output power curve of the novel WEC is relatively smooth, which is conducive to its smooth operation and subsequent utilization and storage of electrical energy.
25
Marrec, P., T. Cariou, E. Macé, P. Morin, L. A. Salt, M. Vernet, B. Taylor, K. Paxman, and Y. Bozec. "Dynamics of air–sea CO<sub>2</sub> fluxes in the North-West European Shelf based on Voluntary Observing Ship (VOS) and satellite observations." Biogeosciences Discussions 12, no. 7 (April 14, 2015): 5641–95. http://dx.doi.org/10.5194/bgd-12-5641-2015.
Повний текст джерелаАнотація:
Abstract. From January 2011 to December 2013, we constructed a comprehensive pCO2 dataset based on voluntary observing ship (VOS) measurements in the Western English Channel (WEC). We subsequently estimated surface pCO2 and air–sea CO2 fluxes in north-west European continental shelf waters using multiple linear regressions (MLRs) from remotely sensed sea surface temperature (SST), chlorophyll a concentration (Chl a), the gas transfer velocity coefficient (K), photosynthetically active radiation (PAR) and modeled mixed layer depth (MLD). We developed specific MLRs for the seasonally stratified northern WEC (nWEC) and the permanently well-mixed southern WEC (sWEC) and calculated surface pCO2 with relative uncertainties of 17 and 16 μatm, respectively. We extrapolated the relationships obtained for the WEC based on the 2011–2013 dataset (1) temporally over a decade and (2) spatially in the adjacent Celtic and Irish Seas (CS and IS), two regions which exhibit hydrographical and biogeochemical characteristics similar to those of WEC waters. We validated these extrapolations with pCO2 data from the SOCAT database and obtained relatively robust results with an average precision of 4 ± 22 μatm in the seasonally stratified nWEC and the southern and northern CS (sCS and nCS), but less promising results in the permanently well-mixed sWEC, IS and Cap Lizard (CL) waters. On an annual scale, seasonally stratified systems acted as a sink of CO2 from the atmosphere of −0.4, −0.9 and −0.4 mol C m−2 year−1 in the nCS, sCS and nWEC, respectively, whereas, permanently well-mixed systems acted as source of CO2 to the atmosphere of 0.2, 0.4 and 0.4 mol C m−2 year−1 in the sWEC, CL and IS, respectively. Air–sea CO2 fluxes showed important inter-annual variability resulting in significant differences in the intensity and/or direction of annual fluxes. We scaled the mean annual fluxes over six provinces for the last decade and obtained the first annual average uptake of −0.95 Tg C year−1 for this part of the north-western European continental shelf. Our study showed that combining VOS data with satellite observations can be a powerful tool to estimate and extrapolate air–sea CO2 fluxes in sparsely sampled area.
26
Wang, Daming, Daniel Conley, Martyn Hann, Keri Collins, Siya Jin, and Deborah Greaves. "Power output estimation of WEC with HF radar measured complex representative sea states." International Marine Energy Journal 5, no. 1 (June 8, 2022): 1–10. http://dx.doi.org/10.36688/imej.5.1-10.
Повний текст джерелаАнотація:
Wave tank model testing has been widely used to assess the performance of Wave Energy Converters (WEC) in different technology readiness levels (TRL). At early stage the use of simple wave conditions such as regular waves and parametric wave spectrum JONSWAP or Pierson-Moskowitz spectrum is acceptable. However at later stages there is a need to use site specific complex wave conditions representative of potential prototype deployment sites. In previous research, 10 different regrouping methods on HF radar measured wave spectrum were tested to find out the most representative sea states for tank testing. It has been shown that by using the K-means clustering technique, the characteristics of wave conditions can be well preserved. In order to assess the power capture performance of a typical WEC in these representative sea states, the RM3 point absorber has been simulated. By analysing how well the average power output predicted from different representative sea-state selection methods compares with the total power output prediction, it is shown that the non-directional wave spectrum K-means clustering method provides the most representative sea states and, for a point absorber, with a very accurate estimation of the total power output, which is not the case by using a traditional binning method. The importance of using the complex site-specific sea states rather than simplified parametric JONSWAP sea states to obtain the accurate total power estimation has also been shown.
27
Cortés, Jaime, Felipe Lucero, Leandro Suarez, Cristian Escauriaza, Sergio A. Navarrete, Gonzalo Tampier, Cristian Cifuentes, et al. "Open Sea Lab: An integrated Coastal Ocean Observatory Powered by Wave Energy." Journal of Marine Science and Engineering 10, no. 9 (September 5, 2022): 1249. http://dx.doi.org/10.3390/jmse10091249.
Повний текст джерелаАнотація:
Current advances in wave energy technologies have enabled the development of new integrated measurement platforms powered by the energy of wave motion. Instrumentation is now being deployed for the long-term observation of the coastal ocean, with the objectives of analyzing the performance of wave energy converters (WECs) and studying their interactions with the surrounding environment and marine life. In this work, we present the most relevant findings of the installation and initial operation of the Open Sea Lab (OSL), the first coastal observatory in Latin America powered entirely by a WEC device. We evaluated the preliminary data regarding the combined operation of the system, the generation of energy, and the observations obtained by the continuous monitoring of physical variables at the site. The data showed the seasonal variability of the energy produced by the WEC for a range of wave heights during the period of observation. We also investigated the rapid development of biofouling on mooring lines, junction boxes, and other parts of the system, which is characteristic of the settlement and growth of organisms in this ocean region. These analyses show how this new facility will advance our understanding of the coastal environment in the south Pacific Ocean and foster new interdisciplinary collaborations addressing environmental and technical challenges, thereby contributing to the development of wave energy on the continent.
28
Bonfanti, Mauro, Andrew Hillis, Sergej Antonello Sirigu, Panagiotis Dafnakis, Giovanni Bracco, Giuliana Mattiazzo, and Andrew Plummer. "Real-Time Wave Excitation Forces Estimation: An Application on the ISWEC Device." Journal of Marine Science and Engineering 8, no. 10 (October 21, 2020): 825. http://dx.doi.org/10.3390/jmse8100825.
Повний текст джерелаАнотація:
Optimal control strategies represent a widespread solution to increase the extracted energy of a Wave Energy Converter (WEC). The aim is to bring the WEC into resonance enhancing the produced power without compromising its reliability and durability. Most of the control algorithms proposed in literature require for the knowledge of the Wave Excitation Force (WEF) generated from the incoming wave field. In practice, WEFs are unknown, and an estimate must be used. This paper investigates the WEF estimation of a non-linear WEC. A model-based and a model-free approach are proposed. First, a Kalman Filter (KF) is implemented considering the WEC linear model and the WEF modelled as an unknown state to be estimated. Second, a feedforward Neural Network (NN) is applied to map the WEC dynamics to the WEF by training the network through a supervised learning algorithm. Both methods are tested for a wide range of irregular sea-states showing promising results in terms of estimation accuracy. Sensitivity and robustness analyses are performed to investigate the estimation error in presence of un-modelled phenomena, model errors and measurement noise.
29
Alamian, Rezvan, Rouzbeh Shafaghat, and Mohammad Reza Safaei. "Multi-Objective Optimization of a Pitch Point Absorber Wave Energy Converter." Water 11, no. 5 (May 9, 2019): 969. http://dx.doi.org/10.3390/w11050969.
Повний текст джерелаАнотація:
In this paper, a pitch point absorber wave energy converter (WEC) is selected in order to be optimized for the wave characteristics of the Caspian Sea. The optimization process is a multi-objective optimization. For achieving the optimal WEC, mean absorbed power should be maximized while the construction cost should be minimized. The submerged surface area of the WEC is selected as a cost parameter. The amount of mean absorbed power depends on the installation site and also the shape of the WEC. For optimizing the shape of the WEC, various shapes are considered which are categorized into three different sections. A multi-objective genetic algorithm is used for optimization of the model, and the NEMOH software is used to simulate the wave-body interaction. The results show that the bottom flat and upside chamfered geometry with X:Y ratio of 10:1 is the best geometry for the desired application. Comparing the results from the final optimized shape with the optimized basic parallelepipedic hull shape reveals that much more extractable power can be achieved with less cost.
30
Sirigu, Sergej Antonello, Mauro Bonfanti, Ermina Begovic, Carlo Bertorello, Panagiotis Dafnakis, Giuseppe Giorgi, Giovanni Bracco, and Giuliana Mattiazzo. "Experimental Investigation of the Mooring System of a Wave Energy Converter in Operating and Extreme Wave Conditions." Journal of Marine Science and Engineering 8, no. 3 (March 7, 2020): 180. http://dx.doi.org/10.3390/jmse8030180.
Повний текст джерелаАнотація:
A proper design of the mooring systems for Wave Energy Converters (WECs) requires an accurate investigation of both operating and extreme wave conditions. A careful analysis of these systems is required to design a mooring configuration that ensures station keeping, reliability, maintainability, and low costs, without affecting the WEC dynamics. In this context, an experimental campaign on a 1:20 scaled prototype of the ISWEC (Inertial Sea Wave Energy Converter), focusing on the influence of the mooring layout on loads in extreme wave conditions, is presented and discussed. Two mooring configurations composed of multiple slack catenaries with sub-surface buoys, with or without clump-weights, have been designed and investigated experimentally. Tests in regular, irregular, and extreme waves for a moored model of the ISWEC device have been performed at the University of Naples Federico II. The aim is to identify a mooring solution that could guarantee both correct operation of the device and load carrying in extreme sea conditions. Pitch motion and loads in the rotational joint have been considered as indicators of the device hydrodynamic behavior and mooring configuration impact on the WEC.
31
Prasetyowati, Ane, Wisnu Broto, and Noor Suryaningsih. "LINEAR GENERATOR PROTOTYPE WITH VERTICAL CONFIGURATION OF SEA WAVE POWER PLANT." Spektra: Jurnal Fisika dan Aplikasinya 6, no. 3 (December 30, 2021): 185–200. http://dx.doi.org/10.21009/spektra.063.05.
Повний текст джерелаАнотація:
There are three types of potential energy sources in the sea: ocean wave energy, tidal energy, and ocean heat energy. Ocean wave energy is a source of considerable energy. Sea waves are an up and down movement of seawater where the energy of sea waves is generated through the effect of air pressure movement due to fluctuations in ocean wave movements. The Ocean Wave Power Plant can use ocean wave energy to convert it into electrical energy. A linear generator is a device that can convert the mechanical energy of linear motion into electrical energy. The application of the ocean wave energy conversion technology, a linear generator system is an electrical machine that functions to convert the mechanical energy of linear motion into electrical energy using the principle of electromagnetic induction. Wave Energy Converter (WEC) technology has been developed with various methods. From the various existing concepts and designs, in general, WEC technology can be classified into three main types, namely Attenuator (horizontal configuration), Point Absorber (linear configuration), Terminator (damping configuration).
32
Katsidoniotaki, Eirini, Yi-Hsiang Yu та Malin Göteman. "Midfidelity model verification for a point-absorbing wave energy converter with linear power take-off". International Marine Energy Journal 5, № 1 (15 червня 2022): 67–75. http://dx.doi.org/10.36688/imej.5.67-75.
Повний текст джерелаАнотація:
In the preliminary design stage of a waveenergy converter (WEC), researchers need fast and reliablesimulation tools. High-fidelity numerical models are usu-ally employed to study the wave-structure interaction, butthe computational cost is demanding. As an alternative,midfidelity models can provide simulations in the order ofreal time. In this study, we operate Uppsala University’sWEC in a relatively mild sea state and model it usingWEC-Sim. The model is verified based on OpenFOAMsimulations. To analyze the ability of the midfidelitymodel to capture WEC dynamics, we investigate the systemseparately with 1, 2, and 3 degrees of freedom. We examinethe contribution of viscous phenomena, and study bothlinear and weakly nonlinear solutions provided by WEC-Sim. Our results indicate that the viscous effects can beneglected in heave and surge motion, but not for pitch.We also find that the weakly nonlinear WEC-Sim solutionsuccessfully agrees with the computational fluid dynam-ics, whereas the linear solution could suggest misleadingresults.
33
Yang, Hyunjai, Hyen-Cheol Jung, and WeonCheol Koo. "Oscillating Water Column (OWC) Wave Energy Converter Part 1: Fixed OWC." Journal of Ocean Engineering and Technology 36, no. 4 (August 31, 2022): 280–94. http://dx.doi.org/10.26748/ksoe.2022.009.
Повний текст джерелаАнотація:
<i>This study reviews the recent development and research results of a fixed oscillating water column (OWC) wave energy converter (WEC). The OWC WEC can be divided into fixed and floating types based on the installation location and movement of the structure. In this article, the study on a stationary OWC WEC, which is close to commercialization through the accumulation of long-term research achievements, is divided into five research categories with a focus on primary energy conversion research. These research categories include potential-flow-based numerical analysis, wave tank experiments, computational fluid dynamics analyses toward investigation of fluid viscous effects, U-shaped OWC studies that can amplify water surface displacement in the OWC chamber, and studies on OWC prototypes that have been installed and operated in real sea environments. This review will provide an overview of recent research on the stationary OWC WEC and basic information for further detailed studies on the OWC.</i>
34
Homayoun, Esmaeil, Hassan Ghassemi, and Hamidreza Ghafari. "Power Performance of the Combined Monopile Wind Turbine and Floating Buoy with Heave-type Wave Energy Converter." Polish Maritime Research 26, no. 3 (September 1, 2019): 107–14. http://dx.doi.org/10.2478/pomr-2019-0051.
Повний текст джерелаАнотація:
Abstract This study deals with a new concept of near-shore combined renewable energy system which integrates a monopile wind turbine and a floating buoy with heave-type wave energy converter( WEC). Wave energy is absorbed by power-take-off (PTO) systems. Four different shapes of buoy model are selected for this study. Power performance in regular waves is calculated by using boundary element method in ANSYS-AQWA software in both time and frequency domains. This software is based on three-dimensional radiation/diffraction theory and Morison’s equation using mixture of panels and Morison elements for determining hydrodynamic loads. For validation of the approach the numerical results of the main dynamic responses of WEC in regular wave are compared with the available experimental data. The effects of the heaving buoy geometry on the main dynamic responses such as added mass, damping coefficient, heave motion, PTO damping force and mean power of various model shapes of WEC in regular waves with different periods, are compared and discussed. Comparison of the results showed that using WECs with a curvature inward in the bottom would absorb more energy from sea waves.
35
Neshat, Mehdi, Nataliia Y. Sergiienko, Erfan Amini, Meysam Majidi Nezhad, Davide Astiaso Garcia, Bradley Alexander, and Markus Wagner. "A New Bi-Level Optimisation Framework for Optimising a Multi-Mode Wave Energy Converter Design: A Case Study for the Marettimo Island, Mediterranean Sea." Energies 13, no. 20 (October 20, 2020): 5498. http://dx.doi.org/10.3390/en13205498.
Повний текст джерелаАнотація:
To advance commercialisation of ocean wave energy and for the technology to become competitive with other sources of renewable energy, the cost of wave energy harvesting should be significantly reduced. The Mediterranean Sea is a region with a relatively low wave energy potential, but due to the absence of extreme waves, can be considered at the initial stage of the prototype development as a proof of concept. In this study, we focus on the optimisation of a multi-mode wave energy converter inspired by the CETO system to be tested in the west of Sicily, Italy. We develop a computationally efficient spectral-domain model that fully captures the nonlinear dynamics of a wave energy converter (WEC). We consider two different objective functions for the purpose of optimising a WEC: (1) maximise the annual average power output (with no concern for WEC cost), and (2) minimise the levelised cost of energy (LCoE). We develop a new bi-level optimisation framework to simultaneously optimise the WEC geometry, tether angles and power take-off (PTO) parameters. In the upper-level of this bi-level process, all WEC parameters are optimised using a state-of-the-art self-adaptive differential evolution method as a global optimisation technique. At the lower-level, we apply a local downhill search method to optimise the geometry and tether angles settings in two independent steps. We evaluate and compare the performance of the new bi-level optimisation framework with seven well-known evolutionary and swarm optimisation methods using the same computational budget. The simulation results demonstrate that the bi-level method converges faster than other methods to a better configuration in terms of both absorbed power and the levelised cost of energy. The optimisation results confirm that if we focus on minimising the produced energy cost at the given location, the best-found WEC dimension is that of a small WEC with a radius of 5 m and height of 2 m.
36
Tan, Jian, Xuezhou Wang, Henk Polinder, Antonio Jarquin Laguna, and Sape A. Miedema. "Downsizing the Linear PM Generator in Wave Energy Conversion for Improved Economic Feasibility." Journal of Marine Science and Engineering 10, no. 9 (September 17, 2022): 1316. http://dx.doi.org/10.3390/jmse10091316.
Повний текст джерелаАнотація:
A crucial part of wave energy converters (WECs) is the power take-off (PTO) mechanism, and PTO sizing has been shown to have a considerable impact on the levelized cost of energy (LCOE). However, as a dominating type of PTO system in WECs, previous research pertinent to PTO sizing did not take modeling and optimization of the linear permanent magnet (PM) generator into consideration. To fill this gap, this paper provides an insight into how PTO sizing affects the performance of linear permanent magnet (PM) generators, and further the techno-economic performance of WECs. To thoroughly reveal the power production of the WEC, both hydrodynamic modeling and generator modeling are incorporated. In addition, three different methods for sizing the linear generator are applied and compared. The effect of the selection of the sizing method on the techno-economic performance of the WEC is identified. Furthermore, to realistically reflect the relevance of PTO sizing, wave resources from three European sea sites are considered in the techno-economic analysis. The dependence of PTO sizing on wave resources is demonstrated.
37
Ayob, Mohd Nasir, Valeria Castellucci, Johan Abrahamsson, and Rafael Waters. "A Remotely Controlled Sea Level Compensation System for Wave Energy Converters." Energies 12, no. 10 (May 21, 2019): 1946. http://dx.doi.org/10.3390/en12101946.
Повний текст джерелаАнотація:
The working principle of the wave energy converter (WEC) developed at Uppsala University (UU) is based on a heaving point absorber with a linear generator. The generator is placed on the seafloor and is connected via a steel wire to a buoy floating on the surface of the sea. The generator produces optimal power when the translator's oscillations are centered with respect to the stator. However, due to the tides or other changes in sea level, the translator's oscillations may shift towards the upper or lower limit of the generator's stroke length, resulting in a limited stroke and a consequent reduction in power production. A compensator has been designed and developed in order to keep the generator's translator centered, thus compensating for sea level variations. This paper presents experimental tests of the compensator in a lab environment. The wire adjustments are based on online sea level data obtained from the Swedish Meteorological and Hydrological Institute (SMHI). The objective of the study was to evaluate and optimize the control and communication system of the device. As the device will be self-powered with solar and wave energy, the paper also includes estimations of the power consumption and a control strategy to minimize the energy requirements of the whole system. The application of the device in a location with high tides, such as Wave Hub, was analyzed based on offline tidal data. The results show that the compensator can minimize the negative effects of sea level variations on the power production at the WEC. Although the wave energy concept of UU is used in this study, the developed system is also applicable to other WECs for which the line length between seabed and surface needs to be adjusted.
38
Dialyna, Evangelia, and Theocharis Tsoutsos. "Wave Energy in the Mediterranean Sea: Resource Assessment, Deployed WECs and Prospects." Energies 14, no. 16 (August 5, 2021): 4764. http://dx.doi.org/10.3390/en14164764.
Повний текст джерелаАнотація:
A detailed review of wave energy resource assessment and the state-of-the-art of deployed wave energy converters (WECs) in real environmental conditions in the Mediterranean Sea have been analysed in this study. The installed power of the several deployed WECs in the Mediterranean Sea varies between 3–2500 kW. Ten project cases of deployed WECs in the basin are presented, with their analysis of the essential features. Five different types of WEC have already been tested under real environmental conditions in Italy, Greece, Israel and Gibraltar, with Italy being the Mediterranean country with the most deployed WECs. The main questions of the relevant studies were the ongoing trends, the examination of WECs in combination with other renewable sources, the utilising of WECs for desalination, and the prospects of wave energy in the Mediterranean islands and ports. This paper is the first comprehensive study that overviews the recent significant developments in the wave energy sector in the Mediterranean countries. The research concludes that the advances of the wave energy sector in the Mediterranean Sea are significant. However, in order to commercialise WECs and wave energy exploitation to become profitable, more development is necessary.
39
Evans, D. V., and R. Porter. "Wave energy extraction by coupled resonant absorbers." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 370, no. 1959 (January 28, 2012): 315–44. http://dx.doi.org/10.1098/rsta.2011.0165.
Повний текст джерелаАнотація:
In this article, a range of problems and theories will be introduced that will build towards a new wave energy converter (WEC) concept, with the acronym ‘ROTA’ standing for resonant over-topping absorber. First, classical results for wave power absorption for WECs constrained to operate in a single degree of freedom will be reviewed and the role of resonance in their operation highlighted. Emphasis will then be placed on how the introduction of further resonances can improve power take-off characteristics by extending the range of frequencies over which the efficiency is close to a theoretical maximum. Methods for doing this in different types of WECs will be demonstrated. Coupled resonant absorbers achieve this by connecting a WEC device equipped with its own resonance (determined from a hydrodynamic analysis) to a new system having separate mass/spring/damper characteristics. It is shown that a coupled resonant effect can be realized by inserting a water tank into a WEC, and this idea forms the basis of the ROTA device. In essence, the idea is to exploit the coupling between the natural sloshing frequencies of the water in the internal tank and the natural resonance of a submerged buoyant circular cylinder device that is tethered to the sea floor, allowing a rotary motion about its axis of attachment.
40
Fernández, Gael, Vasiliki Stratigaki, and Peter Troch. "Irregular Wave Validation of a Coupling Methodology for Numerical Modelling of Near and Far Field Effects of Wave Energy Converter Arrays." Energies 12, no. 3 (February 8, 2019): 538. http://dx.doi.org/10.3390/en12030538.
Повний текст джерелаАнотація:
Between the Wave Energy Converters (WECs) of a farm, hydrodynamic interactions occur and have an impact on the surrounding wave field, both close to the WECs (“near field” effects) and at large distances from their location (“far field” effects). To simulate this “far field” impact in a fast and accurate way, a generic coupling methodology between hydrodynamic models has been developed by the Coastal Engineering Research Group of Ghent University in Belgium. This coupling methodology has been widely used for regular waves. However, it has not been developed yet for realistic irregular sea states. The objective of this paper is to present a validation of the novel coupling methodology for the test case of irregular waves, which is demonstrated here for coupling between the mild slope wave propagation model, MILDwave, and the ‘Boundary Element Method’-based wave–structure interaction solver, NEMOH. MILDwave is used to model WEC farm “far field” effects, while NEMOH is used to model “near field” effects. The results of the MILDwave-NEMOH coupled model are validated against numerical results from NEMOH, and against the WECwakes experimental data for a single WEC, and for WEC arrays of five and nine WECs. Root Mean Square Error (RMSE) between disturbance coefficient (Kd) values in the entire numerical domain ( R M S E K d , D ) are used for evaluating the performed validation. The R M S E K d , D between results from the MILDwave-NEMOH coupled model and NEMOH is lower than 2.0% for the performed test cases, and between the MILDwave-NEMOH coupled model and the WECwakes experimental data R M S E K d , D remains below 10%. Consequently, the efficiency is demonstrated of the coupling methodology validated here which is used to simulate WEC farm impact on the wave field under the action of irregular waves.
41
Wu, Guoheng, Zhongyue Lu, Zirong Luo, Jianzhong Shang, Chongfei Sun, and Yiming Zhu. "Experimental Analysis of a Novel Adaptively Counter-Rotating Wave Energy Converter for Powering Drifters." Journal of Marine Science and Engineering 7, no. 6 (June 1, 2019): 171. http://dx.doi.org/10.3390/jmse7060171.
Повний текст джерелаАнотація:
Nowadays, drifters are used for a wide range of applications for researching and exploring the sea. However, the power constraint makes it difficult for their sampling intervals to be smaller, meaning that drifters cannot transmit more accurate measurement data to satellites. Furthermore, due to the power constraint, a modern Surface Velocity Program (SVP) drifter lives an average of 400 days before ceasing transmission. To overcome the power constraint of SVP drifters, this article proposes an adaptively counter-rotating wave energy converter (ACWEC) to supply power for drifters. The ACWEC has the advantages of convenient modular integration, simple conversion process, and minimal affection by the crucial sea environment. This article details the design concept and working principle, and the interaction between the wave energy converter (WEC) and wave is presented based on plane wave theory. To verify the feasibility of the WEC, the research team carried out a series of experiments in a wave tank with regular and irregular waves. Through experiments, it was found that the power and efficiency of the ACWEC are greatly influenced by parameters such as wave height and wave frequency. The maximum output power of the small scale WEC in a wave tank is 6.36 W, which allows drifters to detect ocean data more frequently and continuously.
42
Yu, Yi-Hsiang, and Dale Jenne. "Numerical Modeling and Dynamic Analysis of a Wave-Powered Reverse-Osmosis System." Journal of Marine Science and Engineering 6, no. 4 (November 8, 2018): 132. http://dx.doi.org/10.3390/jmse6040132.
Повний текст джерелаАнотація:
A wave energy converter (WEC) system has the potential to convert the wave energy resource directly into the high-pressure flow that is needed by the desalination system to pump saltwater to the reverse-osmosis membrane and provide the required pressure level to generate freshwater. In this study, a wave-to-water numerical model was developed to investigate the potential use of a wave-powered desalination system (WPDS) for water production. The model was developed by coupling a time-domain radiation-and-diffraction method-based numerical tool (WEC-Sim) for predicting the hydrodynamic performance of WECs with a solution-diffusion model that was used to simulate the reverse-osmosis (RO) process. The objective of this research is to evaluate the WPDS dynamics and the overall efficiency of the system. To evaluate the feasibility of the WPDS, the wave-to-water numerical model was applied to simulate a desalination system that used an oscillating surge WEC device to pump seawater through the system. The hydrodynamics WEC-Sim simulation results for the oscillating surge WEC device were validated against existing experimental data. The RO simulation was verified by comparing the results to those from the Dow Chemical Company’s reverse osmosis system analysis (ROSA) model, which has been widely used to design and simulate RO systems. The wave-to-water model was then used to analyze the WPDS under a range of wave conditions and for a two-WECs-coupled RO system to evaluate the influence of pressure and flow rate fluctuation on the WPDS performance. The results show that the instantaneous energy fluctuation from waves has a significant influence on the responding hydraulic pressure and flow rate, as well as the recovery ratio and, ultimately, the water-production quality. Nevertheless, it is possible to reduce the hydraulic fluctuation for different sea states while maintaining a certain level of freshwater production, and a WEC array that produces water can be a viable, near-term solution to the nation’s water supply. A discussion on the dynamic impact of hydraulic fluctuation on the WPDS performance and potential options to reduce the fluctuation and their trade-offs is also presented.
43
Bouchonneau, Nadège, Arnaud Coutrey, Vivianne Marie Bruère, Moacyr Araújo, and Alex Costa da Silva. "Finite Element Modeling and Simulation of a Submerged Wave Energy Converter System for Application to Oceanic Islands in Tropical Atlantic." Energies 16, no. 4 (February 8, 2023): 1711. http://dx.doi.org/10.3390/en16041711.
Повний текст джерелаАнотація:
The development of efficient and sustainable marine energy converter systems is a great challenge, especially in remote areas such as oceanic islands. This work proposes a numerical modeling methodology to assess the mechanical behavior of a wave energy converter (WEC) to be applied outside Fernando de Noronha Island (Pernambuco, Brazil). First, oceanographic data collected in situ were analyzed to determine different sea state scenarios in the region. The Airy theory and second-order Stokes’ theory were used to obtain the velocity profiles for the maximum and operational swells. These profiles were then implemented in a flow model developed in COMSOL Multiphysics software (Burlington, MA, USA) to calculate the wave distributions of pressure on the WEC structure. Finally, wave pressure distributions obtained from simulations were implemented in a static analysis of the system by the finite element method using SolidWorks (France). The results highlighted the most critical system inclination and the parts of the WEC structure more likely to be damaged under extreme swell conditions. The 0° inclination was the most critical situation, leading to the exceeding of the elastic limits of some parts of the WEC structure. The methodology developed in this work showed to be efficient to study and propose project improvement for the strength of the WEC system.
44
Clément, A. H., and A. Babarit. "Discrete control of resonant wave energy devices." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 370, no. 1959 (January 28, 2012): 288–314. http://dx.doi.org/10.1098/rsta.2011.0132.
Повний текст джерелаАнотація:
Aiming at amplifying the energy productive motion of wave energy converters (WECs) in response to irregular sea waves, the strategies of discrete control presented here feature some major advantages over continuous control, which is known to require, for optimal operation, a bidirectional power take-off able to re-inject energy into the WEC system during parts of the oscillation cycles. Three different discrete control strategies are described: latching control, declutching control and the combination of both, which we term latched–operating–declutched control. It is shown that any of these methods can be applied with great benefit, not only to mono-resonant WEC oscillators, but also to bi-resonant and multi-resonant systems. For some of these applications, it is shown how these three discrete control strategies can be optimally defined, either by analytical solution for regular waves, or numerically, by applying the optimal command theory in irregular waves. Applied to a model of a seven degree-of-freedom system (the SEAREV WEC) to estimate its annual production on several production sites, the most efficient of these discrete control strategies was shown to double the energy production, regardless of the resource level of the site, which may be considered as a real breakthrough, rather than a marginal improvement.
45
Yao, Tao, Yulong Wang, Zhihua Wang, Tongxian Li, and Zhipeng Tan. "Research on Energy-Capture Characteristics of a Direct-Drive Wave-Energy Converter Based on Parallel Mechanism." Energies 15, no. 5 (February 23, 2022): 1670. http://dx.doi.org/10.3390/en15051670.
Повний текст джерелаАнотація:
Aiming at the capture and conversion of multidirection wave energy, a multifreedom direct-drive wave-energy converter (WEC) based on a parallel mechanism is studied. The dynamic model of WEC was conducted based on force analysis and hydrodynamic theory, and the inverse kinematic solutions of each branch chain of the mechanism were obtained following the space vector method. Furthermore, the kinetics response of the linear generator branch chain was obtained. Moreover, the influence on the capture efficiency of the device’s geometric structure scale was investigated under different sea conditions. To evaluate the performance of the WEC, a linear generator model was simulated and analyzed by COMSOL Multiphysics. A laboratory prototype was manufactured. The test results indicated that the multifreedom device can achieve better power conversion performance than traditional single degree of freedom (DOF) devices. This study provides ideas for the design and development of large multi-DOF wave-energy-conversion devices.
46
Naty, Stefania, Antonino Viviano, and Enrico Foti. "FEASEABILITY STUDY OF A WEC INTEGRATED IN THE PORT OF GIARDINI NAXOS, ITALY." Coastal Engineering Proceedings, no. 35 (June 23, 2017): 22. http://dx.doi.org/10.9753/icce.v35.structures.22.
Повний текст джерелаАнотація:
This paper presents the feasibility study for a green touristic infrastructure by the installation of a WEC system in the port of Giardini Naxos, in the Mediterranean Sea. The area is characterized by a low amount of annual wave energy. The WEC system chosen is the OWC and its geometry has been tested by means of a small scale physical model. The surface elevation and the pressure on the structure have been recorder in such tests in order to evaluate, respectively, loadings and reflection at the front wall. The eigenperiod of the water column inside the device is also obtained. Finally, the economic return is estimated.
47
Hong, Yue, Mikael Eriksson, Cecilia Boström, Jianfei Pan, Yun Liu, and Rafael Waters. "Damping Effect Coupled with the Internal Translator Mass of Linear Generator-Based Wave Energy Converters." Energies 13, no. 17 (August 27, 2020): 4424. http://dx.doi.org/10.3390/en13174424.
Повний текст джерелаАнотація:
The damping effect, induced inside the linear generator, is a vital factor to improve the conversion efficiency of wave energy converters (WEC). As part of the mechanical design, the translator mass affects the damping force and eventually affects the performance of the WEC by converting wave energy into electricity. This paper proposes research on the damping effect coupled with translator mass regarding the generated power from WEC. Complicated influences from ocean wave climates along the west coast of Sweden are also included. This paper first compares three cases of translator mass with varied damping effects. A further investigation on coupling effects is performed using annual energy absorption under a series of sea states. Results suggest that a heavier translator may promote the damping effect and therefore improve the power production. However, the hinder effect is also observed and analyzed in specific cases. In this paper, the variations in the optimal damping coefficient are observed and discussed along with different cases.
48
Michailides, Constantine. "Ηydrodynamic Response and Produced Power of a Combined Structure Consisting of a Spar and Heaving Type Wave Energy Converters". Energies 14, № 1 (4 січня 2021): 225. http://dx.doi.org/10.3390/en14010225.
Повний текст джерелаАнотація:
During the past years, researchers have studied both numerically and experimentally multibody wave-wind combined energy structures supporting wind turbines and different types of Wave Energy Converters (WECs); rigid body hydrodynamic assumptions have been adopted so far for the development of their numerical models and the assessment of their produced power. In the present paper a numerical model that is based on the use of generalized modes addressing wave-structure interaction effects for the case of a multibody wave-wind combined structure is developed and presented. Afterwards, the developed numerical model is used for the assessment of the hydrodynamic response and the prediction of the produced power of different possible configurations of the updated WindWEC concept which consists of a spar supporting a wind turbine and one, two, three or four heaving type WEC buoys. The combined effects of the center-to-center distance of the WEC and spar platform, the number of the WECs and the grid configuration of spar and WECs on the hydrodynamic interaction between the different floating bodies, spar and WEC buoys, and consequently on their response and wave power production are examined for regular and irregular waves. Strong hydrodynamic interaction effects exist for small distance between spar and WECs that result to the decrease of the produced power. Power matrices of the updated WindWEC concept are presented for all examined configurations with different number of WECs. Moreover, the annual produced power of the updated WindWEC in two sites is estimated and presented. The generalized modes analysis presented in this paper is generic and can be used for the early stage assessment of wave-wind combined energy structures with low computational cost. The updated WindWEC can be used in sea sites with different environmental characteristics while extracting valuable amount of wave power.
49
Sjolte, Jonas, Gaute Tjensvoll, and Marta Molinas. "Self-sustained all-electric wave energy converter system." COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering 33, no. 5 (August 26, 2014): 1705–21. http://dx.doi.org/10.1108/compel-09-2013-0306.
Повний текст джерелаАнотація:
Purpose – The purpose of this paper is to describe the design and function of Fred. Olsen's wave energy converter (WEC) system Lifesaver with special focus on the stand-alone electrical system that is implemented for operation without grid-connection. Design/methodology/approach – The paper focus on the detailed design of the DC-Link system that drives the industrial 400 VAC inverters and generators for the production system. The DC-Link is stabilized by an ultra capacitor bank and has no external source or grid-connection. Findings – The system has been tested through extensive sea trials since April 2012 and has proved its function. Some results from real sea testing are presented. Practical implications – This paper proves the viability of the specified design and may serve as a basis for the design if similar systems in the future. Originality/value – This paper presents a WEC system that has proven successful operation through practical tests, and is therefore regarded as a high-value paper as there is limited experience on this subject.
50
Liu, Wang, Tang, Mao, Mi, Zhang, and Liu. "Reliability Assessment of Water Hydraulic-Drive Wave-Energy Converters." Energies 12, no. 21 (November 2, 2019): 4189. http://dx.doi.org/10.3390/en12214189.
Повний текст джерелаАнотація:
The main objective of the current paper is to determine fatigue critical details of wave-energy converters (WECs) and to evaluate their reliability. For this purpose, a new model of a water-hydraulic drive WEC is designed based on the IPS (company Interproject Service) buoy working principle, and the hydrodynamic frequency domain analysis method is carried out accordingly. A reliability assessment method, which combines the stress-number (SN) curves approach and linear damage cumulative theory, has been developed specifically for the proposed WEC. In order to obtain the stochastic wave load spectrum, 22 years of wave data of the intended deployment site (South China Sea), covering the span of 1988–2009, were analyzed, discussed and processed. A finite element analysis model is also established to calculate the maximum Von Mises stress of the fatigue critical component. The reliability indices and configuration parameters of the water hydraulic-drive WEC are obtained by applying first order reliability method, considering the uncertainty of the model parameters and the fatigue limit state. Optimization of configuration parameters is also developed based on the reliability method for the sake of approaching the expected service life. The results show that the fatigue life of the water turbine can reach the design service life of 20 years as the configuration parameters meet the specific condition. The cumulative reliability index and annual reliability index are recommended as 2.1 and 3.5, respectively.