PRODUCTS & SERVICES - Renewable Energy Technology - Wave Energy

WECA - Wave Energy Conversion Activator

A new type of Wave Energy Conversion Activator device, codenamed WECA, according to the results deducted by the theoretical and experimental research concluded so far. The original full scale model WECA design proposed is made of steel, so as to be suitable for mounting on the run up wall of breakwaters or other rigid or floating structures.The material is by no means exclusive, as any other suitable material providing similar mechanical strength properties would comply, provided that scale economics allow it. It is hereby important to denote the suitability of the device for mounting either onto onshore, nearshore or offshore structures. Functionally, it serves the purpose of absorbing most of the energy of the impacting waves and turn it into compressed air (subsequently converted into electric power or other form of work). The contents included in this report, provide a minimal description of the primary theoretical aspects involved in the overall device behavior. Emphasis is given to the development dynamics concerning the behavior of a hydrodynamic phenomenon, resembling a virtual "Wedge" of kinetic energy rushing into the WECA's interior chamber. The codename nomenclature used for this phenomenon is C.M.W. (Critical Momentum Wedge principle). Next, a preliminary approach to develop a computer simulation model, for rendering the hydrodynamic behavior of progressive waves along modified seabed profiles was realized. This was followed by the respective approximate analysis for their interaction with the WECA device.

Furtheron, a cumulative estimation of the energy levels captured from the respective wavelengths considered as well as the delivered pressure ratios are also indicated.

At the project assessment, an experimental full scale prototype (a 7 m height and 6 m width model, two joined units used) was considered, so as to actually amply enable a wide variety of manufacturing and engineering aspects to become apparent, prior to advancing into the actual construction. The expected delivered power output is around 20 KW. A substantial amount of post-intermediate research has been completed allowing preliminary simulation and modeling of fluid dynamics, as expected to appear in the areas outside and inside the WECA's enclosure. Besides several engineering problems, mostly associated to stresses, materials and the geometry of the pilot model itself, some further advanced aspects appeared. These are closely related to the theoretical background of the governing principles for the "Hydrodynamic Wedge" characteristics, also demanding a mature solution. Therefore, our design merits have been refocused on advanced subjects, such as resonant effects of high speed fluid flow within non- uniformal ducts, impedance matching between highly different -by means of specific volume- thermodynamic fluids, synchronization of impedance matching effects between hydrostatic potential and "Wedge" related momentum, focusing in case of variable direction of incident waves, etc. Although a minor amount of theoretical and simulation work is still need to be completed, adequate experience has been already accumulated as to allow successful pilot modeling and subsequent industrial normalization.

At the very limited scope of this report, a brief account of theoretical deductions is outlayed, expressed in the form of obtainable pressure, as delivered by the WECA device, for a certain range of monochromatic sea conditions. For comparison purposes, the equivalent conditions have been applied to a simple cylindrical cross-section O.W.C. (Oscillating Water Column) device - currently the only viably proposed Wave Energy exploitation solution, with equivalent aperture area. This provides adequate evidence for both devices and their subsequently employed methodologies for wave energy extraction, to be compared. Only the wave upheave cycle results are depicted in the graphs and the exhaust valves of both devices remained closed to the end of the cycle.

Finally, an energy capture diagram for the full tested range of operations was obtained for both devices, followed by the estimated specific and average efficiencies diagram.

WECA early prototypes: Design Details for mounting on a Breakwater run-up wall	WECA early prototypes: Computer Rendering for mounting on a Breakwater run-up wall
Comparative diagram indicating Average & Specific Energy Capture Efficiency % for the WECA & OWC devices	Comparative diagram indicating Cumulative & Specific Energy Capture for the WECA & OWC devices
Compressed Air variation diagram as delivered by the WECA device w.r.t. Wavelength and Time	Compressed Air variation diagram as delivered by the OWC device w.r.t. Wavelength and Time