uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Wave energy converter with enhanced amplitude response at frequencies coinciding with Swedish west coast sea states by use of a supplementary submerged body
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
2009 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 106, no 6, article id 064512Article in journal (Refereed) Published
Abstract [en]

The full-scale direct-driven wave energy converter developed at Uppsala University has been in offshore operation at the Swedish west coast since 2006. Earlier simulations have now been validated by full-scale experiment with good agreement. Based on that, a theoretical model for a passive system having optimum amplitude response at frequencies coinciding with Swedish west coast conditions has been developed. The amplitude response is increased by adding supplementary inertia by use of the additional mass from a submerged body. A sphere with neutral buoyancy is chosen as the submerged body and modeled as being below the motion of the waves. The model is based on potential linear wave theory and the power capture ratio is studied for real ocean wave data collected at the research test site. It is found that the power capture ratio for the two body system can be increased from 30% to 60% compared to a single body system. Increased velocity in the system also decreases the value for optimal load damping from the generator, opening up the possibility to design smaller units.

Place, publisher, year, edition, pages
USA: American Institute of Physics , 2009. Vol. 106, no 6, article id 064512
Keywords [en]
data acquisition, ocean waves
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:uu:diva-113142DOI: 10.1063/1.3233656ISI: 000270378100147ISBN: 0021-8979 (print)OAI: oai:DiVA.org:uu-113142DiVA, id: diva2:289898
Note

10907471 Wave Energy Converter enhanced amplitude response Swedish west coast sea states supplementary submerged body Uppsala University offshore operation passive system optimum amplitude response neutral buoyancy waves motion potential linear wave theory power capture ratio ocean wave data collection research test site Two Body System single body system

Available from: 2010-01-25 Created: 2010-01-25 Last updated: 2017-12-12Bibliographically approved
In thesis
1. Hydrodynamic Modelling for a Point Absorbing Wave Energy Converter
Open this publication in new window or tab >>Hydrodynamic Modelling for a Point Absorbing Wave Energy Converter
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Surface gravity waves in the world’s oceans contain a renewable source of free power on the order of terawatts that has to this date not been commercially utilized. The division of Electricity at Uppsala University is developing a technology to harvest this energy. The technology is a point absorber type wave energy converter based on a direct-driven linear generator placed on the sea bed connected via a line to a buoy on the surface.

The work in this thesis is focused mainly on the energy transport of ocean waves and on increasing the transfer of energy from the waves to the generator and load. Potential linear wave theory is used to describe the ocean waves and to derive the hydrodynamic forces that are exerted on the buoy. Expressions for the energy transport in polychromatic waves travelling over waters of finite depth are derived and extracted from measured time series of wave elevation collected at the Lysekil test site. The results are compared to existing solutions that uses the simpler deep water approximation. A Two-Body system wave energy converter model tuned to resonance in Swedish west coast sea states is developed based on the Lysekil project concept. The first indicative results are derived by using a linear resistive load. The concept is further extended by a coupled hydrodynamic and electromagnetic model with two more realistic non-linear load conditions.

Results show that the use of the deep water approximation gives a too low energy transport in the time averaged as well as in the total instantaneous energy transport. Around the resonance frequency, a Two-Body System gives a power capture ratio of up to 80 percent. For more energetic sea states the power capture ratio decreases rapidly, indicating a smoother power output. The currents in the generator when using the Two-Body system is shown to be more evenly distributed compared to the conventional system, indicating a better utilization of the electrical equipment. Although the resonant nature of the system makes it sensitive to the shape of the wave spectrum, results indicate a threefold increase in annual power production compared to the conventional system.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2011. p. 91
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 878
Keywords
Ocean wave energy, Point absorber, Wave energy converter, Wave energy transport, Polychromatic wave, Linear generator, Resonance, Finite depth, Modelling
National Category
Electrical Engineering, Electronic Engineering, Information Engineering Marine Engineering Oceanography, Hydrology and Water Resources
Research subject
Engineering Science with specialization in Electronics
Identifiers
urn:nbn:se:uu:diva-160319 (URN)978-91-554-8214-5 (ISBN)
Public defence
2011-12-09, Häggsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 13:15 (English)
Opponent
Supervisors
Available from: 2011-11-17 Created: 2011-10-21 Last updated: 2018-01-12Bibliographically approved

Open Access in DiVA

fulltext(660 kB)203 downloads
File information
File name FULLTEXT01.pdfFile size 660 kBChecksum SHA-512
7be0d071b9afae3b951831ea5d4fde1374f599fe7a425ae97dd52de30b136928c1cb2a5523169ca7c0aa29c94282f49dad01699cca1e88c627b7d44841878411
Type fulltextMimetype application/pdf

Other links

Publisher's full text

Authority records BETA

Engström, JensIsberg, JanLeijon, Mats

Search in DiVA

By author/editor
Engström, JensIsberg, JanLeijon, Mats
By organisation
Electricity
In the same journal
Journal of Applied Physics
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar
Total: 203 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

doi
isbn
urn-nbn

Altmetric score

doi
isbn
urn-nbn
Total: 673 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf