Monthly Archives: May 2012

A Permanent Magnet Generator for Energy Conversion from Marine Currents: No Load and Load Experiments


K Thomas, M Grabbe, K Yuen, M Leijon –The Swedish Centre for Renewable Electric Energy Conversion and Department of Engineering Sciences, May 2012

Abstract
This paper presents experiments and measurements on a low speed permanent magnet cable wound generator for marine current energy conversion. Measurements were made for no load and nominal load (4.44Ω/phase) conditions at nominal speed (10 rpm). For either load condition, the magnetic fields in the air gap were also measured. The measurements on the generator were compared with the corresponding finite element method simulations used to design the machine. It is shown in the paper that measurements and corresponding case simulations show good agreement. At nominal speed, the measured and simulated load voltages (nominal load) differ less than 1% for the rms values and less than 5% for peak values. At no load, measured and simulated voltages had larger differences, that is, <9% for rms values and <5% for peak values. Harmonic analyses of measured and simulated phase voltages and currents show only the presence of third harmonics. The percentage of harmonics in the measured data was comparable with the corresponding predictions of the simulations. The discussions and results presented in the paper could be beneficial for future design of efficient and reliable marine current energy converter systems.

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Prototyping a series of bi-directional horizontal axis tidal turbines for optimum energy conversion


P Liu, N Bose – Applied Energy, May 2012

Highlights
► A new series of bi-directional HATT rotors was developed. ► A generic wind/tidal turbine rotor design and optimization procedure was developed. ► An unsteady, time-domain, and efficient panel method was developed and validated. ► The code finished over 15,000 runs in 3 months while a RANS CFD will take 50 years. ► A 53% power efficiency was achieved to produce extra energy of 1230 MW h/year.

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Impeller wheel wave energy generator CFD analysis


S Wang, F Zhang, Z Wang – 2012 International Conference on Systems and Informatics, May 2012

Abstract
The ocean contains mass of clean and renewable energy in many types, the wave energy is one of them. Though the wave energy is wildly distributed, its low quality needs the devices with special design to capture the energy efficiency. Shanghai Ocean University has proposed an impeller wheel wave energy generator. To ensure its efficiency, the impeller CFD analysis is required. In this article, the relationship of single grade impeller and distance of double grades was simulated and discussed. And finally find out the most appropriate design parameters.

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Numerical benchmarking study of a selection of wave energy converters


A Babarit, J Hals, MJ Muliawan, A Kurniawan, T Moan, J Krokstad- Renewable Energy, May 2012

Highlights
► 8 Wave Energy Converters with different working principles are calculated. ► Using numerical modelling, their power matrices are estimated. ► Annual energy production and power measures are calculated at five different sites. ► Comparison shows that despite very different levels of energy production, power measures are of similar order of magnitudes.

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Computational methods for performance analysis of horizontal axis tidal stream turbines


JH Lee, S Park, DH Kim, SH Rhee, MC Kim – Applied Energy, October 2012

Abstract

In the present study, two computational procedures, based on the blade element momentum theory and computational fluid dynamics, were developed for open water performance prediction of horizontal axis tidal stream turbines. The developed procedures were verified by comparison with other computational results and existing experimental data and then, applied to a turbine design process. The results of the open water performance prediction were discussed in terms of the efficiency and accuracy of the design process. For better cavitation inception performance, a raked tip turbine design was proposed and analyzed with the developed procedure.

Highlights
► Efficient procedures to predict the performance of tidal stream turbines were developed. ► A BEMT code was developed and validated for quick performance evaluation of a design. ► A CFD code was developed for detailed flow features around full-scale tidal stream turbines. ► A new tidal stream turbine design was suggested for cavitation suppression.

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In-Stream Tidal Power: A Literature Review


CP Kuang, XT Zhao, Y Pan, J Gu – Advanced Materials Research, May 2012

Abstract
Under the energy crisis, the development of new energy has become one of the top issues for countries in the world. In-stream tidal power is a young generation technology to exploit the tidal energy, whose potential has been attached great importance to by many countries. Turbine is the core components of the in-stream tidal power generation system. In this paper the relatively mature technology is summarized extensively. Recent years many countries have pay a lot of attentions to in-stream tidal power and set the future development goals. For both the development stage and installed capacity China have a larger gap with western foreign, but the research of the in-stream tidal power device in China already has made great progress, and the development of in-stream tidal power generation technologies has show great advantages in the protection of the environment, sustainable development of economic and social and mitigation of the energy crisis.

 

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Study on the Dynamic Characteristic for Spar Type Floating Foundation of Offshore Wind Turbine


RY Zhang, CH Chen, Y Tang – Applied Mechanics and Materials, May 2012

Abstract
In this paper, the dynamic behaviors are studied for Spar type floating foundation of a 3kW in the 10m deep water considering the coupled wind turbine-tower-floating foundation and mooring lines and ocean environment load effects. The paper focus on the key issues of design of floating foundation, such as coupling dynamic analysis model and calculating method. The finite element models are established and dynamic responses of floating wind turbine system under different combinations of turbulent wind, constant current and irregular wave are calculated in frequency and time domain with SESAM software. The motion performance and lines’ tension are investigated, and some valuable conclusions are drawn. The results show that the Spar type floating foundation and mooring system can work in the ocean environment which significant wave height less than 2m, the designed large water-entrapment plate can minimized the motion of floating foundation obviously.

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Alternative energy scenarios for small islands: A case study from Salina Island (Aeolian Islands, Southern Italy)


APF Andaloro, R Salomone, L Andaloro, N Briguglio, S Sparacia – Renewable Energy, November 2012

Highlights
► It was evaluated the energy production by RES on Salina island (southern Italy). ► The study aims to verify the contribution by RES to overall energy requirement. ► It were conducted 2 simulations based on photovoltaic and wind power technologies. ► It was estimated the productivity of the whole year and of June–September period. ► The formulated scenarios are in accordance with the 2009 guideline approved by Region.

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Research of Offshore Wind Power Generation Technology


YN Guo, Y Zhang, J Wang, Y Huang – Advanced Materials Research, May 2012

Abstract
Offshore wind farm development direction is from shallow sea to sea . In this paper, according to the current on the wind power base also can not meet the requirements of the problem deep, analysed the base cost will not be particularly high reason. In view of the Hainan offshore wind power, put forward the design train of thought, the analysis obtained an ideal design model.

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Analysis of Environmental Characteristics and Operational Reports of Small and Medium Turbines


AMS Florescu, G Bandoc, M Degeratu – Applied Mechanics and Materials, May 2012

Abstract
Application of environmental policies to prevent climate change, mitigation of climate change, the progressive reduction of emissions of greenhouse gases under commitments, encourage reducing energy consumption by using technologies that are efficient and support production of cheap and clean energy sources should be a priority for contemporary society. Given the above goals, the application presented in this article represents a model of how we addressed the question of the correct size of local wind turbines to provide energy coverage of a community. This method involves an analysis of environmental factors, followed by the analysis of wind in the area and continued to calculate the energy potential of the area and capable energy and wind turbines provided consumer choice.

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