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.
Sunday, June 28, 2009
Thursday, June 25, 2009
Green Power @ Home -- Energy Storage
All this talk about green energy and conservation has many people wondering...how? I hope this blog will help to clarify that. Today I'd like to talk about planning.
A poorly planned system will have lower efficiency, and therefore the amount of power that can be extracted from the system will be low. Proper planning and design of the entire system will ensure that it will work optimally.
I like to talk about planning these systems in three parts: generation, storage, and distribution. In the full-scale power grid, there is little storage. Much of the grid is focused on generation and distribution. On a small scale, the importance of storage is magnified.
Solar power is only available during the day, and sometimes the wind doesn't blow at all. Clearly, using these forms of energy at home means also designing a storage system. Typically batteries are used to store this energy, however they have some disadvantages. Batteries are heavy, and in order to store large amounts of power for a long period of time, large banks of batteries are required.
There are some technologies that are being developed on a large scale that could be useful for longer term and larger scale energy storage at home. For example, compressed air energy storage is being studied to deal with the intermittancy problem with wind power and to increase wind penetration. Pumped hydro storage could be useful in places where there is a large reservoir of water such as a river or lake.
All of these technologies have the potential to be used in your home green power system at relatively low cost.
For more information on building your own wind turbine and solar panels, check out Home Energy Focus.
A poorly planned system will have lower efficiency, and therefore the amount of power that can be extracted from the system will be low. Proper planning and design of the entire system will ensure that it will work optimally.
I like to talk about planning these systems in three parts: generation, storage, and distribution. In the full-scale power grid, there is little storage. Much of the grid is focused on generation and distribution. On a small scale, the importance of storage is magnified.
Solar power is only available during the day, and sometimes the wind doesn't blow at all. Clearly, using these forms of energy at home means also designing a storage system. Typically batteries are used to store this energy, however they have some disadvantages. Batteries are heavy, and in order to store large amounts of power for a long period of time, large banks of batteries are required.
There are some technologies that are being developed on a large scale that could be useful for longer term and larger scale energy storage at home. For example, compressed air energy storage is being studied to deal with the intermittancy problem with wind power and to increase wind penetration. Pumped hydro storage could be useful in places where there is a large reservoir of water such as a river or lake.
All of these technologies have the potential to be used in your home green power system at relatively low cost.
For more information on building your own wind turbine and solar panels, check out Home Energy Focus.
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