Saturday, April 18, 2009

Rooftop Wind Turbine - The Future is Nearly Here

One of the main disadvantages of wind power for the homeowner is that most of us live in urban settings, and with current technology the ideal conditions for generating electricity with the wind occur outside our cities. This is because wind current is affected by obstacles, and wind close to the ground becomes very turbulent after contact with trees, buildings and other obstacles. The turbulent wind is not only unreliable as a steady power source, it can wreak havoc on the mechanics of most wind turbine designs.

The way around this problem is to raise wind turbines high into the air, generally on poles or trusses. In order to get to the steady airflow, a turbine must be at least 30ft above the highest obstacle. The higher the turbine, the faster the airflow and the more efficient the energy output.

Unfortunately, our cities are less than ideal for this kind of system. Other than the higher office buildings, getting height above obstacles is tricky and installation becomes an expensive affair when considering small ground space, power lines, trees and other objects. Also, there is the problem of city and town ordinances, most of which will have some provision against erecting towers in ones yard. Wind turbines still have a bad rap in many places, even though the designs have improved significantly over the last few decades and many of the old arguments against them are now moot.

That is the situation such as it is right now. However, small wind turbine designs are capable of generating enough electricity to at least augment a household or, in the case of an extremely efficient home, run it completely. Rooftop wind turbines are slowly becoming a reality, and as homeowners strive for independence from power utilities, more designers will put their efforts into coming up with viable designs for residential applications and not just for mega-projects like giant wind farms.

Currently there are only two small rooftop wind turbines available (or nearly available) on the market: the Swift Wind Turbine and the Helyx Urban Turbine. The Swift's main selling point is that it is very quiet and it can be rooftop mounted, without vibrations running through the household. However, it also has a blade span of seven feet, which means it is no small thing to install a unit of that size onto an ordinary residence.

The Helyx Urban Turbine is a much more interesting unit. It is specifically designed as a rooftop unit, and measures only 52 inches in height. It is a vertical axis unit, which means the blades spin around the upright pole perpendicular to your roof. Generally this is a less efficient design, but in a rooftop application it may be exactly what is required to overcome turbulence and still achieve a high enough speed to generate electricity. The company that manufactures the Helyx is hoping to sell them at $2000, which puts them in range of most homeowners. The design is in beta right now so we will have to wait and see how well the Helyx Urban Turbine performs.

For the do-it-yourselfer, the options are many. There are plenty of designs all over the internet, and some guidebooks for sale that can show you how to make your own wind turbine that could potentially be rooftop mounted.

Autor: Hess Marten

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Added: April 18, 2009