SmallWindPower@Home - Impact assessment of building-mounted small wind turbines on performance, people, building and environment

Initial situation, problem to solve and motivation

Following the objective to create sustainable and resilient urban energy supply that doesn't rely purely on the supply from surrounding areas, it is necessary to harvest urban energy potentials in the best possible manner. Alongside photovoltaics, the application of roof-mounted small wind turbines in urban and densely populated areas is one of the few promising alternatives to achieve the ambition of the EU-building directive with the requirement of "nearly zero energy buildings". Paired with the growing desire for private energy autonomy, this circumstance elevates small wind turbines (SWT) into focal topic for private households and communities in densely populated or urban areas. A growingly popular option is to install SWT on the roof of buildings. Due to a lack of experience in this regard, environmental impacts and poorly performing turbines are often caused by these installations. Scarce yields, disturbances and frequent failures are consequences of these design errors. In addition, safety aspects and environmental impacts of SWT such as noise, vibrations and oscillations need to be considered in order to avoid life quality constraints for neighbours.

Goals and level of innovation

In order to give planners the necessary knowledge to consider these aspects, a number of assessments has been performed. These assessments have been performed on different types of SWT which have been installed on different types of buildings and monitored throughout the project. The main goals of these assessments were:

• The evaluation of the impact of complex obstacles (buildings with various roof types) on the surrounding wind flow as well as on the wind flow feeding the SWT under real life conditions.
• Metrological assessment of the impact of various building mounted SWT on the performance (yield, lifetime, ...) as well as on the building, its residents ant the immediate surroundings. The assessment included acoustic measurements, measurements of body borne noise, oscillation measurements and the evaluation of safety aspects

Methods

In order to reach these goals two building replicas with different roof shapes (flat roof, gabled roof) have been erect in the Lichtenegg research park. Whilst in previous research, only simulations or scaled wind tunnel tests on these topics have been performed, this infrastructure allows to monitor SWT directly on a building under real life conditions and to assess its impacts. In order to do so, the following parameters were recorded:

• Wind conditions around the building (wind speed, wind direction, turbulence intensity and frequency)
• Power output and selected operational parameters of the turbines (RPM, ...)
• Vibrations and oscillations at the turbine as well as in the building
• Noise emissions end infrasound in proximity as well as body borne sound in the building

Within the framework of holistic assessment the measurement results were supplemented with a technological impact assessment (life cycle assessment, economical assessment, repercussions on concerned parties).

Results and findings, outlook

Based on the achieved results and experiences a list of criteria for SWT in urban or densely populated areas and building mounted SWT was deducted. Furthermore, a catalogue of requirements for testing end certifying building mounted SWT was developed. In order to make the results available for the public, a guideline for planning, installing and operating a building mounted SWT was concluded.

Project management

Kurt Leonhartsberger, University of Applied Sciences Technikum Wien, Department of Renewable Energy

Project or cooperation partners

• Energiewerkstatt Verein
• Solvento energy consulting gmbH
• Zentralanstalt für Meteorologie und Geodynamik
• Sensenwerk Sonnleithner GmbH

University of Applied Sciences Technikum Wien, Department of Renewable Energy
Kurt Leonhartsberger, MSc.
Giefinggasse 6
A-1210 Vienna
Tel.: +43 (664) 619 25 86
E-mail: kurt.leonhartsberger@technikum-wien.at