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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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7 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Advanced Controls for the Multi-pod Centipod WEC device

Dehlsen Associates, LLC (DA) has developed a Wave Energy Converter (WEC), Centipod, which is a multiple point absorber, extracting wave energy primarily in the heave direction through a plurality of point absorber floats sharing a common stable reference structure. The objective of this project was to develop advanced control algorithms that will be used to reduce Levelized Cost of Energy (LCOE). This project investigated the use of Model Predictive Control (MPC) to improve the power capture of the WEC. The MPC controller developed in this work is a state-space, “look ahead” controller approach using knowledge of past and current states to predict future states to take action with the PTO to maximize power capture while still respecting system constraints. In order to maximize power, which is the product of force and velocity, the controller must aim to create phase alignment between excitation force and velocity. This project showed a 161% improvement in the Annual Energy Production (AEP) for the Centipod WEC when utilizing MPC, compared to a baseline, fixed passive damping control strategy. This improvement in AEP was shown to provide a substantial benefit to the WEC’s overall Cost of Energy, reducing LCOE by 50% from baseline. The results of this work proved great potential for the adoption of Model Predictive Controls in Wave Energy Converters.

16 TIDAL AND WAVE POWER↗
DOE OSTI2014

Determination of reactive oxygen species from ZnO micro-nano structures with shape-dependent photocatalytic activity

Graphical abstract: ZnO micro/nano structures with shape dependent photocatalytic activity were prepared by hydrothermal reaction. The generations of hydroxyl radical, superoxide and singlet oxygen from irradiated ZnO were identified precisely by electron spin resonance spectroscopy. The type of reactive oxygen species was determined by band gap structure of ZnO. - Highlights: • ZnO micro/nano structures with different morphologies were prepared by solvothermal reaction. • Multi-pod like ZnO structures exhibited superior photocatalytic activity. • The generations of hydroxyl radical, superoxide and singlet oxygen from irradiated ZnO were characterized precisely by electron spin resonance spectroscopy. • The type of reactive oxygen species was determined by band gap structure of ZnO. - Abstract: ZnO micro/nano structures with different morphologies have been prepared by the changing solvents used during their synthesis by solvothermal reaction. Three typical shapes of ZnO structures including hexagonal, bell bottom like and multi-pod formed and were characterized by scanning electron microscopy and X-ray diffraction. Multi pod like ZnO structures exhibited the highest photocatalytic activity toward degradation of methyl orange. Using electron spin resonance spectroscopy coupled with spin trapping techniques, we demonstrate an effective way to identify precisely the generation of hydroxyl radicals, superoxide and singlet oxygen from the irradiated ZnO multi pod structures. The type of reactive oxygen species formed was predictable from the band gap structure of ZnO. These results indicate that the shape of micro-nano structures significantly affects the photocatalytic activity of ZnO, and demonstrate the value of electron spin resonance spectroscopy for characterizing the type of reactive oxygen species formed during photoexcitation of semiconductors.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Centipod WEC, Advanced Controls, Resultant LCOE

Project resultant levelized cost of energy (LCOE) model after implementation of model predictive control (MPC) controller. Contains annual energy production (AEP) data, cost breakdown structure (CBS), model documentation, and the LCOE content model. This is meant for comparison with this project's baseline LCOE model.

16 TIDAL AND WAVE POWER↗
DOE OSTI2016

Centipod WEC, Advanced Controls, WEC Geometry CAD

CAD files depicting the wetted geometry of the Centipod WEC used in numerical models during this project. This includes the wetted geometry of the point absorber body ('pod') and the WEC 'backbone'.

16 TIDAL AND WAVE POWER↗
DOE OSTI2016

Centipod WEC, Advanced Controls, WaveDyn Models

Archive containing the WaveDyn models used for analysis of the Centipod WEC with and without Advanced Controls, i.e. the WaveDyn files contain a baseline model which can be run alone, and a model predictive control (MPC) model which must be run when connected to the MPC controller. The controller dynamic link library (DLL) is also contained within this archive. The code archive for the MPC controller is linked in this submission.

16 TIDAL AND WAVE POWER↗
DOE OSTI2016

Centipod WEC, Advanced Controls, MPC Controller MATLAB Code

This archive contains the MATLAB code for the model predictive control (MPC) controller developed in this project. The archive containing the WaveDyn models used for analysis of the Centipod with the MPC controller is linked in this submission.

16 TIDAL AND WAVE POWER↗
DOE OSTI2016

Centipod WEC, Advanced Controls, Baseline LCOE

Project baseline levelized cost of energy (LCOE) model for the Centipod WEC containing annual energy production (AEP) data, a cost breakdown structure (CBS), model documentation, and the LCOE content model. This baseline was built for comparison with the resultant LCOE model, built after implementation of the model predictive control (MPC) controller.

16 TIDAL AND WAVE POWER↗