Design and development of a novel wave energy converter

[摘要] ENGLISH ABSTRACT: The design, development and evaluation of a novel wave energy converter (WEC)device, called the ShoreSWEC, in a South African port development is presented.Based on the device requirements, site selection criteria were specified and appliedto identify a suitable deployment location. A wave modeling procedure wasdeveloped to determine the operational wave conditions and available wave powerresource at the selected location. The site was found to have a low mean annualaverage resource of approximately 2.3 kilowatt per meter wave crest (kW/m) due toits relatively sheltered location. The wave model was further used to determinedesign storm conditions and a structural stability analysis of the device wasconducted.Experimental tests were performed to evaluate the hydrodynamic conversionefficiency of a single chamber of the device at its most conservative orientation,under a variety of wave energy conditions. The effect of a floor incline and anadditional chamber on the performance of the system was investigated. The inclineimproved efficiency for low wave heights, making it ideal for the low wave powerresource conditions of the site, whilst the multi-chamber system experiencedincreased performance at high wave periods. A comparison between theShoreSWEC and a conventional oscillating water column (OWC) WEC showed thatthe OWC extracted 72% more energy, highlighting the sensitivity of performance ondevice orientation. A three-dimensional (3D) numerical model of the experimentalsetup was developed. The numerical model provided comparable water surfaceelevations inside the flume and chamber, yet predicted significantly higher internalchamber pressures and overall efficiency. The electricity generation potential of a 10chamber ShoreSWEC at the specified location, approximated from the experimentalresults and 11 years of hindcast wave data, was found to be 6 kW on average for a15 kW capacity system.Results of this study highlighted the need for greater understanding of thehydrodynamic characteristics of a full length device. Experimental tests in a 3D wavebasin on a scaled full length ShoreSWEC model are therefore recommended. Onceconducted, South Africa will be one step closer to the deployment of the full scaleSWEC device.

[发布机构] Stellenbosch University