Sunday, June 28, 2009

DIY Wind Turbine - Resources

Wind turbines are a great way to get started utilizing green energy at home. Unfortunately this isn't a project that you can just jump into without a little research. Home made turbines can be simple affairs, with blades made from wood, to complex pieces with injection molded blade assemblies. In between there are PVC, fiberglass and many other types of blade configurations.

A good place to start, if you're in Canada, is the Wind Atlas. In the US, the Wind Energy Resource Atlas provides similar data. These resources will help you determine if your area receives enough wind on average to make your project worthwhile. This is the first step towards building your wind turbine.

Next, some research on blade design and airfoil selection is in order. The airfoil shape is important for the efficiency of the turbine. The Airfoil Coordinates Database lists many airfoils and gives profiles for them which you can then use as templates for your wind turbine. Complex profiles can be cut from foam and overlaid with fiberglass for strength, or the foam can be used as a mold and the fiberglass can be used on its own.

The shape (planform) of the turbine blades can be determined using Warlock's Blade Calculator. This tool does not give you constant-chord blades, but rather tapered blades. This is more efficient for a few reasons, tapered blades have less mass per length as you move outward, and thus allow the turbine to spin faster. With the more massive parts of the blades closer to the center, the inertia that must be overcome to have the blades start spinning is lower.

We've talked a lot about the turbine blades, as they're what actually makes the thing spin. However, to convert the mechanical energy into electricty, you need a motor of some sort. The motor consists of two portions, a stator and a rotor. The stator is the stationary part of the motor and in order to make construction simpler, the coils are generally placed on the stator, while permanant magnets are placed on the rotor. As the rotor spins, the copper coils magnetize and demagnetize and this creates an electric current.

Next time we'll talk about designing the generation portion of your wind turbine. In the mean time, you can check out plans for DIY turbines and solar panels at Home Energy Focus.

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