Home Built Wind Generators And Turbines For Energy Self Sufficiency
Generating power from wind is the ideal project for backyard experimenters and do it yourself people wishing to become energy self sufficient. A more important aspect of wind power is its ability to complement a solar photovoltaic array in combination solar wind power systems.
Wind generator technology is appropriately low so the construction and maintenance of many home built wind generator designs is well within the technical reach of the competent handyperson. Because home wind power generation is low tech it's a highly appropriate technology for self-sufficient living.
Due to the physical nature of wind power generation it is better suited to rural environments or rural residential situations where installation of towers, turbine noise, perceived threat or aesthetics will not impact upon immediate neighbors.
However
there are new breeds of residential wind power generators suited to
urban environments. Much experimentation and design work has been done
by commercial manufacturers of residential rooftop wind power systems
based on vertical axis designs that provide good ideas for home made wind turbines that could
work in urban situations.
Note: the idea of residential roof top
wind power systems for urban applications as marketed by commercial
interests is largely a "scam" at this stage.
In real life, ideal sites for wind power are few and far between.
Your site will almost certainly be far from ideal. The ideal wind site
is open, elevated, relatively flat and devoid of obstacles that create
turbulence in an area of constant (prevailing) breeze.
Truth be told, the perfect site for wind power production is not an ideal
place to live! The constant wind would drive you nuts and if your aim
was self-sufficiency, the constant high velocity wind would make
self-sufficient gardening that much more difficult.
While your site may not be considered viable for commercial wind energy
production or even for the installation of commercially built units
where the emphasis is on cost/benefit, a home built wind turbine, of low
cost, could still make a substantial contribution to your energy
requirements for self sufficient living.
Design Considerations For Home Built Wind Generators or Turbines
Based on your site a decision will have to be made as to the type of wind turbine required. There are 2 basic types of wind turbine; the more conventional horizontal axis "propeller" type and the vertical axis alternative of which there are a few variations.
Horizontal Axis vs Vertical Axis Wind Generators
Conventional horizontal axis wind generators need very "clean" undisturbed airflow. In general horizontal axis wind generators need to be at least 6 metres above all obstacles within 100 metres.
Turbulent wind causes horizontal axis wind turbines to "hunt" as they constantly seek to realign themselves to face the wind. The gyroscopic forces involved in moving the rotating blade "disc" are enormous, causing fatigue and premature failure. They simply do not perform well in turbulent wind.
If you have an ideal wind site where installation of a tall tower is appropriate the choice of a conventional horizontal axis wind generator is obvious. To date, horizontal axis turbines are the most efficient turbines for "ideal" wind sites.
Vertical axis wind generators on the other hand are always aligned
correctly to the wind. The design allows the turbine to accept energy
from wind at any angle (on the horizontal plane) and for this reason are
superior on many sites despite their lower efficiency. While "clean" non
turbulent air flow is still best, vertical axis wind generators are
able to make the most of sites that are less than ideal.
There are 2 distinct types of wind; prevalent breezes which represent
around 2/3 of wind over time and energy winds that make up the other 1/3
wind over time. Energy winds are caused by local disturbances like
storms and rapid weather changes. Energy winds often account for 70% of
the total wind energy available. Harnessing these often turbulent energy
winds is where small scale home built vertical axis wind turbines can excel.
Land shape and funneling can dramatically boost the energy available.
Through careful observation it's possible to identify specific areas
where wind is funneled and concentrated by gullies, sharp hills and even
openings in timber belts. Again, vertical axis wind generators can make
the most of turbulent funneled airflow.