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

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

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

scholarly journals 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.

Loads and Dynamic Response of a Floating Wave Energy Converter due to Regular Waves From CFD Simulations

2016 ◽  
Author(s):  
Anna Büchner ◽  
Thomas Knapp ◽  
Martin Bednarz ◽  
Philipp Sinn ◽  
Arndt Hildebrandt
Keyword(s):  
Dynamic Response ◽  
Boundary Conditions ◽  
Wave Energy ◽  
Single Point ◽  
Breaking Waves ◽  
Wave Energy Converter ◽  
Wave Loads ◽  
Regular Waves ◽  
Energy Converter ◽  
Set Up

The commercial CFD code ANSYS Fluent is used for the three-dimensional estimation of wave loads and the dynamic response of a floating single point wave energy converter of the SINN Power wave power plant due to non-breaking and unidirectional waves in coastal waters. The VoF method is used to model the free surface and wave theories to set up the boundary conditions at the inlet for regular waves. The wave induced vertical motions of the floating module are computed by a sixDoF solver. Preliminary 2D and 3D studies to set up boundary conditions, mesh densities and solver settings were performed. The numerical results were compared to analytical solutions in form of water surface elevations and wave kinematics which showed good agreement. The paper presents the dynamic response of the floating module for different load cases in terms of non-breaking waves. The resulting horizontal and vertical forces at the floating module will be presented and explained by the flow dynamics. Time and space depending velocities and pressure distributions including details on vortex separation will be given, which reveal valuable insights on the contribution of inertia and drag forces leading to the dynamic structural response of the floating devices.

scholarly journals Effective Mooring Rope Tension in Mechanical and Hydraulic Power Take-Off of Wave Energy Converter

2021 ◽  
Vol 13 (17) ◽  
pp. 9803
Author(s):  
Ji Woo Nam ◽  
Yong Jun Sung ◽  
Seong Wook Cho
Keyword(s):  
Energy Conversion ◽  
Wave Energy ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Energy Conversion Efficiency ◽  
Wave Energy Converter ◽  
Hydraulic Motor ◽  
Energy Converter ◽  
The Individual ◽  
Conversion Efficiencies

The InWave wave energy converter (WEC), which is three-tether WEC type, absorbs wave energy via moored cylindrical buoys with three ropes connected to a terrestrial power take-off (PTO) through a subsea pulley. In this study, a simulation study was conducted to select a suitable PTO when designing a three-tether WEC. The mechanical PTO transfers energy from the buoy to the generator using a gearbox, whereas the hydraulic PTO uses a hydraulic pump, an accumulator, and a hydraulic motor to convert mechanical energy into electrical energy. The hydraulic PTO has a lower energy conversion efficiency than that of the mechanical PTO owing to losses resulting from pipe friction and the individual efficiencies of the hydraulic pumps and motors. However, the efficiencies mentioned above are not the efficiency of the whole system. The efficiency of the whole system should be analyzed considering the tension of the rope and the efficiency of the generator. In this study, the energy conversion efficiencies of the InWave WEC installed the mechanical and hydraulic PTO devices are compared, and their behaviors are analyzed through numerical simulations. The mechanics of mechanical and hydraulic PTO applied to InWave are mathematically expressed, and the issues of the elements constituting the PTO are explained. Finally, factors to consider for PTO selection are presented.

scholarly journals Numerical simulation of a wave energy converter using linear generator

2013 ◽  
Vol 35 (2) ◽  
pp. 103-111 ◽  
Author(s):  
Dang The Ba
Keyword(s):  
Numerical Simulation ◽  
Wave Energy ◽  
Energy Demand ◽  
Wave Energy Converter ◽  
Linear Potential ◽  
Energy Converter ◽  
Wave Condition ◽  
Mechanics Model ◽  
South Central ◽  
Offshore Wave

This paper presents results of numerical simulation for a wave energy converter using linear permanent magnet generator. The use of linear permanent generator has advantages of simple structure, minimizing mechanical loose... On the base of mechanics model, a system of equations describing the operation of the device under linear potential wave was obtained. The magnetic field in generator was calculated by Flex-PDE software. The system of movement equations was numerically solved with Matlab.Various calculations were performed with different parameters of wave conditions and device's structures to determine the device’s configuration for a 300 W output power for the offshore wave condition in South-Central offshore of Vietnam. The results also show potential of developing the wave energy conversion to meet the energy demand in some coastal and island regions of Vietnam.

scholarly journals The Economic Feasibility of Floating Offshore Wave Energy Farms in the North of Spain

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 806 ◽  
Author(s):  
Laura Castro-Santos ◽  
Ana Bento ◽  
Carlos Guedes Soares
Keyword(s):  
Wave Energy ◽  
Net Present Value ◽  
Energy Resource ◽  
Economic Feasibility ◽  
Wave Energy Converter ◽  
Energy Converter ◽  
The North ◽  
Cost Of Energy ◽  
Offshore Wave ◽  
North Of Spain

A technique to analyse the economic viability of offshore farms composed of wave energy converters is proposed. Firstly, the inputs, whose value will be considered afterwards in the economic step, was calculated using geographic information software. Secondly, the energy produced by each wave converter was calculated. Then the economic factors were computed. Finally, the restriction that considers the depth of the region (bathymetry) was put together with the economic outputs, whose value depends on the floating Wave Energy Converter (WEC). The method proposed was applied to the Cantabric and Atlantic coasts in the north of Spain, a region with a good offshore wave energy resource. In addition, three representative WECs were studied: Pelamis, AquaBuoy and Wave Dragon; and five options for electric tariffs were analysed. Results show the Wave Energy Converter that has the best results regarding its LCOE (Levelized Cost of Energy), IRR (Internal Rate of Return) and NPV (Net Present Value), and which area is best for the development of a wave farm.

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