A Numerical Investigation of the Energy Efficiency Enhancement of Oscillating Water Column Wave Energy Converter Systems

Abstract

This work focuses on the geometry effects over the performance of oscillating water column (OWC)-type wave energy converter (WEC) systems and searches for the OWC geometries that enhance the energy efficiencies under the same wave conditions. To analyze the hydrodynamic performances of the WEC systems, an in-house smoothed particle hydrodynamics (SPH) code based on weakly compressible fluid approach is utilized. The energy efficiency enhancement studies of the determined OWC device are carried out with a two-step geometry modification procedure. The first step starts with the validation of the free-surface elevation and orbital velocity time histories. Then, a three-by-three simulation matrix that depends on the geometrical design parameters of chamber length and front wall draft is run at three different wave conditions, and the OWC geometry that produces the maximum energy efficiency is determined. In the second step, the corner regions of the obtained optimal geometry are chamfered, and another simulation matrix is tested at the wave condition that yields maximum wave energy. It is observed in this step that the energy efficiency index can still be improved by 4.3% by only chamfering the back face of the OWC chamber. To scrutinize the physical grounds of this increase, the correlation between the time-averaged vorticity and energy efficiency is presented. Finally, the performance of the best configuration is also examined in three different wave periods, where the suggested geometry shows better performance with respect to base geometry results in all wave conditions.

Improving the OWC Wave Energy Converter Power Take-Off Efficiency throughout Experimental and Numerical Characterisation of an SCIG

“…These losses will be calculated for each test with the adjusted R ′ 2 value and the calculated I ′ 2 as follows. From the equivalent circuit the following expressions, Equations ( 7)- (10), can be obtained:…”

“…Figure 1 shows the representation of the three main types of OWC, where the incoming waves interact with the structure and induce a relative movement of the internal free surface within the water column (the structure plays an important role in the hydrodynamic to swell [9]. Figure 1 shows the representation of the three main types of OWC, where the incoming waves interact with the structure and induce a relative movement of the internal free surface within the water column (the structure plays an important role in the hydrodynamic to pneumatic energy transformation [10]). This motion generates a slow reciprocating airflow, subsequently propelling the turbine installed atop the structure.…”

Modeling and Control Simulation of Power Converters in Automotive Applications

“…Performance improvement: Power electronic converters may have their performance carefully assessed under a range of operating situations, including variations in temperature or load, by using mathematical models and simulations. This makes it possible to adjust converter control and guarantees top performance in a variety of operating conditions [8]. Safety assurance: Through the use of mathematical models and simulations, it is possible to evaluate power electronic converter behavior in the event of overload or failure.…”