Power take-off selection for a fixed U-OWC wave power plant in the Mediterranean Sea: The case of Roccella Jonica

Scialò, Andrea; Henriques, J.C.C.; Malara, Giovanni; Falcão, A.F.O.; Gato, L.M.C.; Arena, Felice

doi:10.1016/j.energy.2020.119085

Cited by 19 publications

(2 citation statements)

References 40 publications

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“…In passing, it is worth mentioning that the same concept was employed recently in operational conditions by utilizing relief valves working in parallel to PTOs. Indeed, Scialò et al (2021) showed that such an implementation is useful for limiting conveniently the turbine rotational speed (via air pressure reduction) with the purpose of ensuring that the PTOs are operating around the optimal working conditions.…”

Section: Turbine Domainmentioning

confidence: 99%

Structural Optimisation and Behaviour of the Breakwater Integrated Oscillating Water Column Device

Goeijenbier

Bricker

Antonini

et al. 2021

Journal of Coastal and Hydraulic Structures

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The Oscillating Water Column (OWC) device is a relatively young and underdeveloped technology for generating electricity from wave energy. Compared to other common renewable sources such as solar and wind energy, the costs for bottom-standing OWC’s are too high for the technology to be economically competitive. A first step in lowering the cost was the integration of OWC devices into breakwaters. Often, OWC are built quite robustly due to insufficient confidence in the magnitude of the extreme loads. This leaves room for optimisation, which so far has not been looked into in detail. In an attempt to lower the costs further, the possibilities for structural optimisation are investigated in this research. The U-OWC device in Civitavecchia, an OWC with an additional vertical duct, is used as a case study and is modelled in 3D in a one-way coupled hydraulic-structural numerical model. The model contained both a fluid domain, i.e. the wave tank, and a solid domain, i.e. the OWC structure. Coupling the two gives direct feedback on the wave impact in terms of a stress state in the structure. By converting the stresses to sectional forces, a new minimally required wall thickness can be found. Comparing these to the original thicknesses of the three main walls gives the optimisation potential of the OWC structure. Numerical simulations were carried out in operational and design conditions for varying geometries. Based on this, it was found the OWC walls could have been built using 35% less concrete on average. The results also led to a new insight on the structural behaviour. Clear trends were found in where and when to expect critical loads. It was also found that the geometrical changes barely had any influence on these properties. These findings were used to develop a new and simple design method, making a full structural analysis redundant. Removing the structural domain and making use of the found property that water pressures are constant over the transverse width, imply that a 2D model would be sufficient, reducing the model size drastically.

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Section: Turbine Domainmentioning

confidence: 99%

Structural Optimisation and Behaviour of the Breakwater Integrated Oscillating Water Column Device

Goeijenbier

Bricker

Antonini

et al. 2021

Journal of Coastal and Hydraulic Structures

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“…Moreover, the performance of the U-OWC is strongly dependent on its geometrical characteristics [11,12], such as the length and the width of the U-duct, the position of its opening below the mean water level, and the width and height of the inner chamber. Further, the optimal selection and control of the Power Take-Off (PTO) system is critical for maximizing the amount of converted energy [13]. In this regard, note that various alternatives to selfrectifying turbines are currently emerging [14].…”

Section: Introductionmentioning

confidence: 99%

Stochastic response determination of U-OWC energy harvesters: a statistical linearization solution treatment accounting for intermittent wave excitation

et al. 2022

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A novel statistical linearization technique is developed for determining approximately the response statistics and the power output of U-Oscillating Water Column (U-OWC) energy harvesting systems. In this regard, first, the governing equations are derived by employing the unsteady Bernoulli equation. Note that the intermittent, i.e., non-stationary, nature of the wave excitation, occurring in severe sea states due to uncovering of the U-OWC inlet, is explicitly accounted for in the herein proposed model. This is done by multiplying the excitation process with a Heaviside function dependent on the instantaneous free surface displacement. Next, the resulting coupled system of nonlinear integro-differential stochastic equations is solved approximately by relying on a statistical linearization technique. Specifically, the original system of nonlinear equations is replaced by an equivalent linear one, whose parameters and response first- and second-order statistics are obtained by minimizing the mean square error between the two systems. A significant novel aspect of the technique relates to the fact that the Heaviside function is replaced in the equivalent linear system by an “equivalent excitation” coefficient to be determined as part of the statistical linearization solution scheme. Further, compared with other relevant solution schemes adopted in earlier research efforts in the literature, it is shown that the developed technique can be construed as a direct generalization that exhibits an enhanced accuracy degree. The U-OWC installed in the Civitavecchia harbor (Rome, Italy) is considered as an illustrative numerical example, where the reliability of the approximate technique is demonstrated by comparisons with pertinent Monte Carlo simulation data.

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Analysis of the Wells Turbine Structure of an Oscillating Water Column Wave Energy System

Jemni

Hentati

Elmbarki

et al. 2021

Lecture Notes in Mechanical Engineering

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Power take-off selection for a fixed U-OWC wave power plant in the Mediterranean Sea: The case of Roccella Jonica

Cited by 19 publications

References 40 publications

Structural Optimisation and Behaviour of the Breakwater Integrated Oscillating Water Column Device

Structural Optimisation and Behaviour of the Breakwater Integrated Oscillating Water Column Device

Stochastic response determination of U-OWC energy harvesters: a statistical linearization solution treatment accounting for intermittent wave excitation

Analysis of the Wells Turbine Structure of an Oscillating Water Column Wave Energy System

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