Due to the increasing global demand for energy and progressing climate change, there is a huge demand for new sources of renewable energy. As an alternative to hydropower, solar, and wind power, energy can be harvested from ocean waves using wave energy converters (WECs). To harvest as much energy as possible from ocean waves, the mass, body shape, and other system parameters of the WECs have to be optimized. For the optimization process, an efficient calculation of the dynamics of the WEC and the associated interaction with the corresponding ocean waves is required.
To optimize the amount of energy harvested by WECs, the Institute of Mechanics and Ocean Engineering (M-13) is implementing and validating a simulation model with which the movements of floating bodies in ocean waves can be calculated and analyzed efficiently. The simulation model is currently being developed to compute the dynamics of a specific WEC. In the future, however, the generated simulation model will be extended to general floating body shapes and will be used to optimize the body shapes of more general WECs. However, the developed simulation model can not only be used to design WECs but also, for example, to determine the safety limits of ships and offshore structures.
In addition to simulations, experimental investigations are also performed in the institute's own 12 m long, 1.5 m wide, and 1.5 m high wave flume, see Fig. 1. In this wave flume, regular water waves with a height of up to 0.6 m and a frequency of up to 2 Hz can be generated. Furthermore, irregular water waves specified by time series can be produced.
With this in mind, various WECs have already been analyzed in the past using simulations and experiments, see [1,2]. Here, it has been investigated how the amount of harvested energy can be increased. In [2], for example, the energy was significantly increased by optimizing important system parameters. In [1], on the other hand, the structure of a WEC, which has been investigated previously by other researchers, was generalized by introducing an inclination angle a, see Fig. 2. It has been shown that the introduction of the inclination angle a could increase the amount of energy harvested from regular waves by up to 500%. Further control strategies can increase this amount of energy even more. These results show that the amount of harvested energy generated from ocean waves can be massively increased by appropriately choosing the values of the system parameters.
Contact:
Prof. Robert Seifried (Tel.: +49 40 42878 3020, robert.seifried(at)tuhh(dot)de)
Marten Hollm (Tel.: +49 40 42878 2308, marten.hollm(at)tuhh(dot)de)
Institute of Mechanics and Ocean Engineering (M-13)
Eißendorfer Straße 42
21073 Hamburg
https://www.tuhh.de/mum/en/research/fields-of-research-and-projects/design-and-analysis-of-wave-energy-converter
Bibliography
[1] Hollm, M.; Dostal, L.; Yurchenko, D.; Seifried, R.: Performance increase of wave energy harvesting of a guided point absorber. The European Physical Journal Special Topics, Vol. 231, No. 8, pp. 1465–1473, 2022. doi:10.1140/epjs/s11734-022-00497-7.
[2] Harms, J.; Hollm, M.; Dostal, L.; Kern, T.A.; Seifried, R.: Design and optimization of a wave energy converter for drifting sensor platforms in realistic ocean waves. Applied Energy, Vol. 321, p. 119303, 2022. doi:10.1016/j.apenergy.2022.119303.
