Urban wind energy - Development of methods for the assessment of small wind turbines in urban areas
Starting point / motivation
Beside photovoltaic the application of roof-mounted small wind turbines in urban areas is promising to achieve the ambition of the EU-building directive with the requirement of "nearly zero energy buildings". On one side there is a lack of innovative concepts for roof-mounted small wind turbines and on the other hand there are still technical planning uncertainties in view of appropriate site selection and the application of small wind turbines at high turbulent wind flow conditions as the mostly occur in urban and suburban areas. Additionally, no safety analyses about the risk potential of small wind turbines in general exist.
Contents and goals
The following 5 questions will be answered in this project:
- How can wind conditions with strong turbulent flow conditions in urban areas be characterised and what kind of measurements and simulation models are suitable for the assessment of urban sites in view of performance and mechanical loads of the small wind turbine?
- What impact do strong turbulent wind flow conditions have on the energy yield, the life expectancy as well as power-quality of the electricity fed into the public grid?
- What is the impact of roof-mounted small wind turbines on the building. What potential risks are arising of roof-mounted SWT in urban areas and how high is the risk potential?
- Which small wind technology is most suitable for urban sites?
- How can a comprehensive site-assessment for small wind turbines urban sites be achieved? What criteria have to be taken into account?
The research will be conducted at representative small wind technologies, comprising a vertical and horizontal small wind turbine, which are mounted on the roof of the ENERGYbase in Wien-Floridsdorf and at the rural site in Lichtenegg. For the selected urban site the turbulent wind flow field will be characterised by the means of measurements and numerical simulations.
The evaluation of different CFD-models enables the assessment of applied models in view of suitability and practicability for wind resource assessment of urban sites in general. Subsequently, the impacts of turbulent wind conditions with reference to selected turbulence indicators on the performance of small wind turbines (SWT) are investigated.
Based on vibration measurements at the SWTs an analysis of the impacts of wind gusts and system immanent loads on a small wind turbine and the resulting vibrations at the rotor of the SWT is conducted. Additionally, the risk and danger for people of roof-mounted small wind turbines in urban areas is investigated, particularly the risk of ice falling and thrown-off ice. The experimental research of the ice falling and thrown-off ice as well as the application of a probalistical safety analysis to determine the risk of fire for roof-mounted SWT are the basis for safety assessments of small wind turbines in general.
The applied method of the project forms the basis for technical and safety assessments of SWT in urban areas in general.
Technikum Wien GmbH, Institut für Erneuerbare Energie