Thermodynamics of an OWC containing real gas

Medina-López, Encarni; Moñino, Antonio; Borthwick, Alistair G.L.; Clavero, María

doi:10.1016/j.energy.2017.06.164

Cited by 19 publications

(4 citation statements)

References 24 publications

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“…But if further calculations concerning the efficiency of the turbine are required, the orifice may be replaced by an Actuator Disk Model in the case of a numerical simulation [62,63]. In order to study the effect of the turbine-chamber coupling in the model, three different orifice sizes (turbine damping) were considered [64].…”

Section: The Physical Modelmentioning

confidence: 99%

A Novel Hybrid Wind-Wave Energy Converter for Jacket-Frame Substructures

2018

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Abstract:The growth of the offshore wind industry in the last couple of decades has made this technology a key player in the maritime sector. The sustainable development of the offshore wind sector is crucial for this to consolidate within a global scenario of climate change and increasing threats to the marine environment. In this context, multipurpose platforms have been proposed as a sustainable approach to harnessing different marine resources and combining their use under the same platform. Hybrid wind-wave systems are a type of multipurpose platform where a single platform combines the exploitation of offshore wind and wave energy. In particular, this paper deals with a novel hybrid wind-wave system that integrates an oscillating water column wave energy converter with an offshore wind turbine on a jacket-frame substructure. The main objective of this paper is to characterise the hydrodynamic response of the WEC sub-system of this hybrid energy converter. A 1:50 scale model was tested under regular and irregular waves to characterise the hydrodynamic response of the WEC sub-system. The results from this analysis lead to the proof of concept of this novel hybrid system; but additionally, to characterising its behaviour and interaction with the wave field, which is a requirement for fully understanding the benefits of hybrid systems.

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Section: The Physical Modelmentioning

confidence: 99%

A Novel Hybrid Wind-Wave Energy Converter for Jacket-Frame Substructures

2018

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“…The Thermodynamics formalism can be applied to relate the initial state of the system in the contraction region with its final state downwind the OWC chamber and turbine. The following rationale and its conclusions have been applied and validated by the authors in previous research, [50].…”

Section: Theoretical Formulationmentioning

confidence: 97%

“…In order to appropriately implement the basic principles concerning the thermodynamic process of air compression and expansion inside the OWC chamber and following the research line traced by the authors in [49,50], a gas system enclosed in a moving and deformable control volume is considered, see figure 1. The situation described in figure 1 might as well represent the process of an air flow being compressed inside an OWC chamber, where the turbine would be mounted at the right end.…”

Section: Process In a Simple Closed Systemmentioning

confidence: 99%

Thermodynamics of the OWC chamber: Experimental turbine performance under stationary flow

et al. 2020

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Among the different devices designed to extract energy from waves, the Oscillating Water Column (OWC) operating an air turbine has been one of the most studied in recent years. The aim of this paper is to study the polytropic exponent associated to the thermodynamic process that takes place through the turbine in a non-idealised environment. A real gas model is applied, considering the influence of the moisture in the air chamber. Experimental data from a simplified OWC chamber set up under stationary flow are interpreted within the frame of an analytical real gas model. For that purpose, thermodynamic variables involved in the compression/expansion process have been calculated with the implementation of a real gas model. Following the results, in which differences between the ideal gas adiabatic polytropic process and the real gas model are observed, a new value for the polytropic exponent is proposed, representing a non-adiabatic real gas behaviour for the air-water vapour mixture. This approach allows a fine adjustment prediction of OWC performance, that can result more realistic in the case of OWC performance prediction under moderate wave climate conditions. From that on, new management guidelines can be developed, in which eventually moderate/low production prospects can be counterbalanced with more efficient and low-cost design.

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“…Furthermore, the effect of air compressibility on the estimation accuracy of the OWC's energy conversion has been studied. The change in an air density due to the air compression and decompression is affected by the pressure, temperature and humidity inside the chamber [25][26][27][28], which leads to a reduction in pneumatic power and a phase difference of the power in the chamber and turbine [25][26][27]29]. Moreover, considering the air compressibility, the OWC's energy conversion performance may vary depending on the scale effect of the model [29,30].…”

Section: Introductionmentioning

confidence: 99%

A Numerical Study on Hydrodynamic Performance of an Inclined OWC Wave Energy Converter with Nonlinear Turbine–Chamber Interaction based on 3D Potential Flow

Kim¹,

Nam

Kim³

et al. 2020

JMSE

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In this study, a time-domain numerical method based on three-dimensional potential flow was developed to analyze the hydrodynamic characteristics of an inclined oscillating-water-column (OWC) wave energy converter (WEC). A finite element method was applied to solve the potential flow around and inside the OWC chamber. A turbine–chamber interaction was considered to take into account the pressure drop inside the OWC chamber, which is a nonlinear function of airflow speed via turbine operation. The instantaneous pressure drop was updated on the free-surface boundary condition inside the chamber in the time-domain to account for the coupling effect between the turbine and the chamber. The present numerical method was verified by comparing it with the model test results. The hydrodynamic characteristics of an inclined OWC chamber in terms of potential flow, such as the water column motion and the three-dimensional flow distribution around the chamber, were investigated. In terms of hydrodynamic performance, the energy conversion efficiency of the chamber showed a nonlinear response characteristic dependent on the incident wave height. In addition, numerical calculations were carried out to clarify the relationship between the main geometric parameters and the hydrodynamic response of the inclined OWC chamber.

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Thermodynamics of an OWC containing real gas

Cited by 19 publications

References 24 publications

A Novel Hybrid Wind-Wave Energy Converter for Jacket-Frame Substructures

A Novel Hybrid Wind-Wave Energy Converter for Jacket-Frame Substructures

Thermodynamics of the OWC chamber: Experimental turbine performance under stationary flow

A Numerical Study on Hydrodynamic Performance of an Inclined OWC Wave Energy Converter with Nonlinear Turbine–Chamber Interaction based on 3D Potential Flow

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