scholarly journals Estimating the optimum size of a tidal array at a multi-inlet system considering environmental and performance constraints

2019 ◽  
Author(s):  
Eduardo González-Gorbeña Eisenmann
Keyword(s):  
Energy Production ◽  
Tidal Energy ◽  
Array Size ◽  
Environmental Constraints ◽  
Energy Extraction ◽  
Energy Converter ◽  
Inlet System ◽  
Array Configuration ◽  
Design Variables ◽  
And Performance

This paper investigates the optimum tidal energy converter array density at a tidal inlet by applying surrogate-based optimisation. The SBO procedure comprises problem formulation, design of experiments, numerical simulations, surrogate model construction and constrained optimisation. This study presents an example for the Faro-Olhão Inlet in the Ria Formosa (Portugal), a potential site for tidal in-stream energy extraction. A 35 kW EvopodTM floating tidal energy converter from Oceanflow Energy Ltd. has been used for array size calculations considering two design variables: 1) number of array rows, and 2) number of tidal energy converter per row. Arrays up to 13 rows with 6 to 11 tidal energy converters each are studied to assess their impacts on array performance, inlets discharges and bathymetry changes. The analysis identified the positive/negative feedbacks between the two design variables in real case complex flow fields under variable bathymetry and channel morphology. The non-uniformity of tidal currents along the array region causes the variability of the resource in each row, as well as makes it difficult to predict the resultant array configuration interactions. Four different multi-objective optimisation models are formulated subject to a set of performance and environmental constraints. Results from the optimisation models imply that the largest array size that meets the environmental constraints is made of 5 rows with 6 tidal energy converter each and an overall capacity factor of 11.6% resulting in an energy production of 1.01 GWh/year. On the other hand, a higher energy production (1.20 GWh/year) is achieved by an optimum array configuration, made of 3 rows with 10 tidal energy converters per row, which maximises power output satisfying environmental and performance restrictions. This optimal configuration permits a good level of energy extraction while having a reduced effect on the hydrodynamic functioning of the multi-inlet system. These results prove the suitability and the potential wide use of the surrogate-based optimisation method to define array characteristics that enhance power production and at the same time respect the environmental surrounding conditions.

scholarly journals Influence of tidal parameters on SeaGen flicker performance

2013 ◽  
Vol 371 (1985) ◽  
pp. 20120247 ◽  
Author(s):  
Joseph MacEnri ◽  
Matthew Reed ◽  
Torbjörn Thiringer
Keyword(s):  
Water Depth ◽  
Strong Relationship ◽  
Tidal Energy ◽  
Graphical Analysis ◽  
Measured Data ◽  
Energy Converter ◽  
Testing Period ◽  
Set Up

This paper presents the analysis of the study of the flicker emitted from the 1.2 MW tidal energy converter (TEC), SeaGen, against varying tidal parameters. This paper outlines the main elements of the TEC itself, the environment it is located in and the measurement set up. In this paper, the flicker emitted by the TEC is compared with the different tidal parameters, including flood and ebb tides, tidal speed, water depth and turbulence strength and intensity. Flicker emissions have been calculated from measured data in over 90 measurement (10 min) periods, and all of the tidal parameters vary significantly over that testing period. This allows for a detailed statistical and graphical analysis of the variation of flicker with the variation of the tidal parameters outlined above. It is found, with the exception of tidal speed, that there is no strong relationship between flicker emissions and any other tidal parameter. As SeaGen is an asymmetrical TEC with full blade pitching for flood and ebb generation, it was also found that the expected difference of flicker emissions owing to the effect of the submersed crossbeam was not significant. The TEC harmonic performance versus tidal speed is also presented.

scholarly journals Estimating the optimum size of a tidal array at a multi-inlet system considering environmental and performance constraints

2018 ◽  
Vol 232 ◽  
pp. 292-311 ◽  
Author(s):  
Eduardo González-Gorbeña ◽  
André Pacheco ◽  
Theocharis A. Plomaritis ◽  
Óscar Ferreira ◽  
Cláudia Sequeira
Keyword(s):  
Optimum Size ◽  
Inlet System ◽  
Performance Constraints ◽  
And Performance

Managing Function Constraints in Design Sheet™

1998 ◽  
Author(s):  
Sudhakar Y. Reddy ◽  
Kenneth W. Fertig
Keyword(s):  
Optimization Problems ◽  
Systems Of Nonlinear Equations ◽  
Graph Theoretic ◽  
Constraint Management ◽  
Constraint Network ◽  
Design Variables ◽  
Large Systems ◽  
And Performance ◽  
Design Cost ◽  
Performance Tradeoff

Abstract Design Sheet™ is a constraint management system specially designed for doing conceptual design cost and performance tradeoff studies. It represents the design models as constraints between design variables, and uses graph-theoretic algorithms to decompose large systems of nonlinear equations into smaller pieces that can be solved robustly. This paper describes extensions to Design Sheet that enable it to manage functions as variables in a constraint network. The paper also discusses the new capabilities of function encapsulation and explicit differentiation that are built on top of these extensions. The ability to encapsulate a part of the constraint network into a function, and use it in other constraints, promotes model reuse and improves computational efficiency. The capability to automatically differentiate certain variables with respect to other design variables allows Design Sheet to be used for solving practical optimization problems. In combination with the tradeoff capability, this enables the designer to track changing optima in trade studies. The paper also provides a couple of optimization examples to demonstrate these new capabilities.

scholarly journals Spatial Information and Performance Evaluation in Coprime Array

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Ying Zhou ◽  
Dazhuan Xu ◽  
Chao Shi ◽  
Weilin Tu ◽  
Junpeng Shi
Keyword(s):  
Mutual Information ◽  
Information Content ◽  
Spatial Information ◽  
Theoretical Expression ◽  
Array Configuration ◽  
Actual Environment ◽  
Uniform Array ◽  
Entropy Error ◽  
And Performance ◽  
Coprime Array

In this paper, the mutual information between the received signals and the source in the coprime linear array is investigated. In Shannon’s information theory, the mutual information is used to quantify the reduction in the priori uncertainty of the transmitted message. Similarly, the spatial information in the coprime array is the mutual information between direction of arrival (DOA), source amplitude, and received signals. Such information content is composed of two parts. The first part is DOA information, and the second one is scattering information. In a single source scenario, we derive the theoretical expression and its asymptotic upper bound of DOA information. The corresponding expression of scattering information is also formulated theoretically. Besides, the application of spatial information is discussed. We can obtain the optimal array configuration by maximizing the DOA information of the coprime array. Similarly, the information is also used to quantify the performance difference between the coprime array and uniform array. In addition, the entropy error is employed to evaluate the estimation performance based on spatial information. Numerical simulation of the information content confirms our theoretical analysis. The results in this paper have important guiding significance for the design of the coprime array in the actual environment.

scholarly journals Performance and Wake Characterization of a Model Hydrokinetic Turbine: The Reference Model 1 (RM1) Dual Rotor Tidal Energy Converter

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5145
Author(s):  
Craig Hill ◽  
Vincent S. Neary ◽  
Michele Guala ◽  
Fotis Sotiropoulos
Keyword(s):  
Reynolds Number ◽  
Reference Model ◽  
Angular Position ◽  
Tidal Energy ◽  
Wake Flow ◽  
Height Velocity ◽  
Scale Model ◽  
Speed Ratio ◽  
Power Performance ◽  
Energy Converter

The mechanical power and wake flow field of a 1:40 scale model of the US Department of Energy’s Reference Model 1 (RM1) dual rotor tidal energy converter are characterized in an open-channel flume to evaluate power performance and wake flow recovery. The NACA-63(4)-24 hydrofoil profile in the original RM1 design is replaced with a NACA-4415 profile to minimize the Reynolds dependency of lift and drag characteristics at the test chord Reynolds number. Precise blade angular position and torque measurements were synchronized with three acoustic Doppler velocimeters (ADV) aligned with each rotor centerline and the midpoint between the rotor axes. Flow conditions for each case were controlled to maintain a hub height velocity, uhub= 1.04 ms−1, a flow Reynolds number, ReD= 4.4 × 105, and a blade chord length Reynolds number, Rec= 3.1 × 105. Performance was measured for a range of tip-speed ratios by varying rotor angular velocity. Peak power coefficients, CP= 0.48 (right rotor) and CP= 0.43 (left rotor), were observed at a tip speed ratio, λ= 5.1. Vertical velocity profiles collected in the wake of each rotor between 1 and 10 rotor diameters are used to estimate the turbulent flow recovery in the wake, as well as the interaction of the counter-rotating rotor wakes. The observed performance characteristics of the dual rotor configuration in the present study are found to be similar to those for single rotor investigations in other studies. Similarities between dual and single rotor far-wake characteristics are also observed.

Simulation of Tidal Energy Extraction by Using FLUENT Model

2019 ◽  
Vol 43 (4) ◽  
pp. 2035-2042
Author(s):  
F. Hosseinibalam ◽  
S. Hassanzadeh ◽  
M. Mirmohammadi
Keyword(s):  
Tidal Energy ◽  
Energy Extraction
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