An Analysis of a Stationary Pneumatic Wave-Energy Converter

1975 ◽  
Vol 97 (3) ◽  
pp. 1015-1019 ◽  
Author(s):  
Michael E. McCormick
Keyword(s):  
Theoretical Analysis ◽  
Energy Conversion ◽  
Wave Height ◽  
Wave Energy ◽  
Power Output ◽  
Peak Power ◽  
Peak Power Output ◽  
Wave Energy Conversion ◽  
Energy Converter ◽  
Resonant Period

A theoretical analysis of a stationary pneumatic wave-energy conversion device is presented. Results obtained from the analysis show that the power converted is proportional to the cube of the wave height, producing a maximum time-averaged power per wave period of 25 kw for a 20-ft (6.096 m) diameter unit located in a 3-ft (0.9144 m) sea. The device can be adjusted for purposes of efficiency in any sea spectrum by simply changing the draft (length of the centerpipe) of the unit. The peak power output of the device occurs at a period similar to the resonant period of a surge chamber.

scholarly journals Design and Analysis for a Floating Oscillating Surge Wave Energy Converter

2014 ◽  
Author(s):  
Yi-Hsiang Yu ◽  
Ye Li ◽  
Kathleen Hallett ◽  
Chad Hotimsky
Keyword(s):  
Energy Conversion ◽  
Structure Analysis ◽  
Wave Energy ◽  
Integrated Design ◽  
Design Strategy ◽  
Wave Energy Converter ◽  
Wave Energy Conversion ◽  
Power Performance ◽  
Energy Converter ◽  
The Cost

This paper presents a recent study on the design and analysis of an oscillating surge wave energy converter (OSWEC). A successful wave energy conversion design requires balance between the design performance and cost. The cost of energy is often used as the metric to judge the design of the wave energy conversion (WEC) system, which is often determined based on the device’s power performance; the cost of manufacturing, deployment, operation, and maintenance; and environmental compliance. The objective of this study is to demonstrate the importance of a cost-driven design strategy and how it can affect a WEC design. A set of three oscillating surge wave energy converter designs was analyzed and used as examples. The power generation performance of the design was modeled using a time-domain numerical simulation tool, and the mass properties of the design were determined based on a simple structure analysis. The results of those power performance simulations, the structure analysis, and a simple economic assessment were then used to determine the cost-efficiency of selected OSWEC designs. Finally, we present a discussion on the environmental barrier, integrated design strategy, and the key areas that need further investigation.

scholarly journals A Rolling Electrical Generator Design and Model for Ocean Wave Energy Conversion

Inventions ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 3
Author(s):  
Praveen Damacharla ◽  
Ali Jamali Fard
Keyword(s):  
Energy Conversion ◽  
Wave Energy ◽  
Weather Conditions ◽  
Electrical Energy ◽  
Wave Energy Conversion ◽  
Energy Converter ◽  
Element Analysis ◽  
Ocean Wave Energy ◽  
Minimum Number ◽  
Two Stages

Wave and tidal energies are some of the most prominent potential sources of renewable energy. Presently, these energy sources are not being utilized to their maximum extent. In this paper, we present a new conversion mechanism with an innovative electrical energy converter design that enables the use of wave energy to its maximum potential. The conventional wave energy converter comprises two stages of conversion (kinetic to mechanical and mechanical to electrical), imposing transformation loss that reduces the overall system efficiency. Additionally, the architecture and operational norms are dependent on the availability of shoreline areas, and the convertor is not suitable for all ocean weather conditions. To solve these problems, we have developed a wave energy conversion system that integrates the two stages of power with the minimum number of moving parts. This results in significant reduction of transformation losses that otherwise occur in the process. This paper presents an innovative idea of designing a DC generator that reduces the hierarchy of power conversion levels involved to improve the efficiency. The back and forth motion of the machine means it operates in a two-quadrant generation mode. The machine was constructed as a square box model with windings placed on both the top and bottom stator plates, and the rotor consisted of a field winding placed between these plates with two axes of operation. The electromagnetic field (EMF) induced in the stator plates is due to the resulting flux cutting, which is generated by a rolling object (rotor) in between them. A finite element analysis (FEA) of the machine is also listed to validate the flux linkage and operational efficiency. Additionally, a generator is fabricated to the predetermined design criteria as a proof of concept and the corresponding results are posted in the paper. Additionally, we present the material and cost limitations of this invention and outline some possible future directions.

Design and Performance Analysis of Anchor System for a Single-Body Wave Energy Converter

2016 ◽  
Author(s):  
Rodrigo L. Banos ◽  
Hirpa G. Lemu
Keyword(s):  
Power Generation ◽  
Energy Conversion ◽  
Wave Energy ◽  
Wave Energy Converter ◽  
Wave Energy Conversion ◽  
Energy Converter ◽  
Practical Solution ◽  
Simulation Tools ◽  
Anchor System ◽  
Single Body

The last couple of decades have observed an increasing interest in development of wave energy conversion technology for both research and commercial purposes. Though slow due to several reasons, the technology shows an evident progress. Because of the oil crisis facing the energy sector in particular, wave energy is currently seen as a good alternative to fossil fuel based power generation. This has marked its footprints on rising industrial ventures in wave energy based power generation and the search for new devices is gearing up. Among the latest invented models, point wave energy converters are attractive and low investment options. These devices are much smaller than the traditional oscillating water column devices and have good performance when combined in arrays of devices, thus placing the technology in the center of industrial and academic research. This article reports the study conducted to understand the mechanics of the energy exchange in a single-body point wave energy converter device model Cape Verde, patented by the Norwegian company Euro Wave Energy. Furthermore, the article intends to give a practical solution for the design of the anchoring problem in the device. In general, the article attempts to present two completely different objectives: an academic part focusing on understanding the wave energy conversion mechanics, and the industrial development part that attempts to find a practical solution for a particular part of the device. The first step involves establishing a model that describes the motion and potential of absorbance of a conic single-body absorber. The anchor system was designed in accordance with standards provided by Det Norske Veritas, the Norwegian regulatory framework. A quasi-static method is used to calculate the load that the absorber would suffer and a pulley and cable system is proposed to drive these loads to the anchor system. After a review of the different solutions offered for offshore facilities at the present time, the model of a suction anchor is chosen. As design verification through physical testing of prototypes of conversion devices is demanding and costly, various simulation tools are appearing in the field. The application range of some of these different simulation tools has been evaluated and reported in this article.

scholarly journals Hydrodynamic Performance of an Asymmetry OWC Device Mounted on a Box-Type Breakwater

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhengzhi Deng ◽  
Pinjie Wang ◽  
Pengda Cheng
Keyword(s):  
Energy Conversion ◽  
Wave Height ◽  
Incident Wave ◽  
Wave Energy ◽  
Short Wave ◽  
Absorption Efficiency ◽  
Hydrodynamic Performance ◽  
Maintenance Cost ◽  
Wave Energy Conversion ◽  
Coupling System

To share the construction and maintenance cost, an asymmetric oscillating water column (OWC) device integrated with a pile-fixed box-typed offshore breakwater is considered experimentally and numerically. A fully nonlinear numerical wave tank is established and validated with the open source solver OpenFOAM. The effects of the width and draft of rear box, and the incident wave height on the wave energy conversion efficiency, reflection and transmission coefficients, and energy dissipation coefficient are examined. In addition, the superiority of the present coupling system, compared to the traditional box-type breakwater, is discussed. With well comparisons, the results show that the existence of the rear breakwater is beneficial for the formation of partial standing waves and further wave energy conversion. In the range of wave heights tested, the higher the incident wave height, the larger the energy absorption efficiency except for the short-wave regimes. Moreover, the OWC-breakwater coupling system can obtain a similar wave blocking ability to the traditional one, and simultaneously extract wave energy and decrease wave reflection.

Comparison of Physical Model Tests With a Time Domain Simulation Model of a Wave Energy Converter

2012 ◽  
Author(s):  
Ryan S. Nicoll ◽  
Charles F. Wood ◽  
André R. Roy
Keyword(s):  
Energy Conversion ◽  
Wave Energy ◽  
Time Domain ◽  
Wave Energy Converter ◽  
Ocean Dynamics ◽  
Time Domain Simulation ◽  
Wave Energy Conversion ◽  
Energy Converter ◽  
Energy Conversion Systems ◽  
The Time Domain

Development of wave energy conversion systems may yield many key benefits for society such as the production of electrical power or fresh water for remote communities. However, complex ocean dynamics make it difficult for technology developers to not only address the stability and survivability of their systems, but also to establish energy conversion rates that are fundamental to proving economic viability. Building physical prototypes presents many challenges in terms of cost, accessible facilities, and time requirements. The use of accurate numerical modelling and computer simulation can help guide design and significantly reduce the number of physical prototype tests required and as a result play a primary role in the development of wave energy conversion systems that have to operate in challenging marine environments. SurfPower is an ocean wave energy converter (WEC) that converts wave motion into useful energy through surge and heave motion of a point absorber. The system pumps seawater into a high pressure hydraulic network that generates electricity via a turbine or freshwater via desalination at a facility onshore. The system is nonlinear due to the significant change in draft and mooring reaction load through the energy capture cycle of the device. This makes the use of nonlinear time domain simulation ideal for analysis and design of the system. Furthermore, utilizing a simplified nonlinear hydrodynamic model available in the time domain results in a practical early-stage design tool for system refinement. The focus of this work is to compare the results of scale model testing completed at the Institute for Ocean Technology in St. John’s, Newfoundland, with results produced from an equivalent system simulated in the time domain simulation software ProteusDS. The results give an assessment of the range of error that can be used to assess other experiments of the SurfPower WEC at full scale.

scholarly journals Turbine Characteristics of Wave Energy Conversion Device for Extraction Power Using Breaking Waves

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 966
Author(s):  
Paresh Halder ◽  
Hideki Takebe ◽  
Krisna Pawitan ◽  
Jun Fujita ◽  
Shuji Misumi ◽  
...  
Keyword(s):  
Energy Conversion ◽  
Wave Energy ◽  
Fluid Dynamic ◽  
Flow Simulation ◽  
Breaking Waves ◽  
Wave Energy Converter ◽  
Constant Thickness ◽  
Prototype Model ◽  
Wave Energy Conversion ◽  
Energy Converter

A new type of wave energy converter which harnesses electricity from onshore breaking waves has been studied at Okinawa Institute of Science and Technology Graduate University (OIST) since 2014. This concept has been demonstrated at a coral beach on the Maldives since 2018. Wave energy conversion is possible when waves approaching the shore steepen due to decreased water depth resulting in wave breaks near the surface. A steepened wave reaches the critical velocity of 4~6 m/sec shoreward before it breaks. A rotating blade takes advantage of this breaking phenomenon to convert the wave energy into electricity. The work presented here includes an experimental and numerical investigation of a prototype model of the wave energy converter. The turbine having five blades of variable chord lengths, twist angles, and constant thickness profile from hub to tip was simulated under similar flow as well as testing conditions, to predict the turbine performance. A commercial computational fluid dynamic tool SolidWorks Flow Simulation 2018 was used for the simulations at various rotation speeds with a uniform inlet velocity. The modified k-ε with a two-scale wall function turbulence closure model was selected. The validation performed for different test cases showed that the present computational results match in good agreement with the experimental results. Additionally, details performance of the turbine running, and generator characteristics have been reported in this paper.

A Theoretical Analysis of a Self-Propelled Backward-Bent Duct Wave Energy Conversion System

1991 ◽  
Vol 113 (2) ◽  
pp. 94-100 ◽  
Author(s):  
M. E. McCormick
Keyword(s):  
Theoretical Analysis ◽  
Energy Conversion ◽  
Wave Energy ◽  
Floating Body ◽  
Forward Speed ◽  
Wave Energy Conversion ◽  
Body Dynamics ◽  
Conversion System ◽  
Energy Conversion System ◽  
System Operating

An analysis of a self-propelled Backward-Bent Duct Barge (BBDB) wave energy conversion system operating at an averaged forward speed is presented. The energy required to propel the system is a parasitic energy of the wave energy conversion subsystem. The analysis includes a feedback between the internal water motions and the floating body dynamics. The performance of the BBDB operating in a design (head) sea is shown to be far superior to both a BBDB in a following sea and a fixed BBDB in a following sea. For this comparison, a 35.6-m long system having a 9.91-m beam and displacing 500 metric tons is studied. The system is also shown to have a positive drift in head seas.

scholarly journals IMPLEMENTATION AND TESTING OF A POWER MATRIX-BASED WAVE ENERGY CONVERSION MODEL AND THE EFFECT SIMULATED ON THE WAVE FIELD — CASE STUDY OF LAGUNA, SC, BRAZIL

2019 ◽  
Vol 18 (1) ◽  
pp. 50
Author(s):  
P. H. Oleinik ◽  
W. C. Marques
Keyword(s):  
Energy Conversion ◽  
Wave Height ◽  
Wave Energy ◽  
Significant Wave Height ◽  
Renewable Energy Sources ◽  
Electrical Energy ◽  
Ocean Waves ◽  
Wave Energy Conversion ◽  
Significant Wave ◽  
Order Of Magnitude

Electrical energy has become an essential resource for mankind and, as the population and technological dependency grow, also does the electricity demand. This necessity boosted numerous studies which focus on clean and renewable energy sources. Ocean wave energy is one of the most environmentally friendly sources of energy since it does not emit pollutants to the atmosphere and does not produce harmful waste. Another positive point about ocean waves is that they are inexhaustible, therefore a power plant could, potentially, provide energy indefinitely. Hence the object of this study is to estimate the wave energy reduction caused by the presence of wave energy conversion (WEC) devices near the coastline of Laguna, Brazil. In order to study the coastal impact of a WEC farm, the third generation sea state model TOMAWAC was used to simulate the waves on the Southern Brazilian Shelf under two different conditions, with and without the presence of an array of WECs. The results show that the mean significant wave height in the blockaded area undergoes a slight drop, caused by the presence of the WECs, which do not appear in the other scenario. But this reduction of the significant wave height is negligible compared to the order of magnitude of the wave height itself.

The Wave Focusing Effect of a Parabolic Wall

2004 ◽  
Author(s):  
J. Wang ◽  
S. M. Calisal ◽  
J. Mikkelsen ◽  
S. Zealand
Keyword(s):  
Energy Conversion ◽  
Wave Height ◽  
Wave Energy ◽  
Relative Size ◽  
Experimental Results ◽  
Wave Forces ◽  
Wave Energy Conversion ◽  
Height Measurement ◽  
Wave Focusing ◽  
Wall Area

The energy generation efficiency of a wave energy conversion system is in general proportional to the capacity of wave energy capture of the system. In various wave energy conversion systems, a configuration with parabolic shape has shown advantages in wave capture dynamics. This paper presents an experimental investigation into the wave focusing and elevation in a parabolic wall area with a Laser Wave Height Measurement equipment named as IVP Ranger SC386. In the experiment, the tested waves were described by a dimensionless factor WF which consists of wave parameters and the parabolic wall size. The WF increases with wave relative size to the model. The tested wave obliquities to the parabolic wall were 10 and 20 degrees in addition to the normal incident waves. A tube with an inner diameter 7.5cm, representing a chamber for oscillatory water columns compressing air, was mounted at the focus area. The elevations of wave height inside the tube with a sealed and an open top, as two different cases, were also measured. Furthermore the wave forces acting on the parabolic wall were measured using load cells. The analysis of the experimental results revealed that the parabolic wall was able to significantly elevate wave heights by up to 2.5 times. Within 10 degrees the wave obliquity effect can be neglected for both forces acting on the parabolic wall and wave height elevated by the parabolic wall. A prediction equation for focusing wave height was developed from the experimental results and the parabolic focusing principle.

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