Friday, October 15, 2010

Homemade V10 Savonius Vertical Axis Wind Turbine

If you are looking at building a homemade wind turbine, there are certain advantages you can get out of building a VAWT (vertical axis wind turbine).  One of these advantages is that they spin rather easily, even in wind that you can barely feel (albeit the tradeoff is that they do not produce as much power as a horizontal, in fact a VAWT will produce about one third the power of a HAWT).  However, the volume of energy produced isn't always the biggest consideration.  A VAWT is more handy when you are dealing with a consistently lower volume of wind, as they spin easier.

Here is an example of a homemade 10w Savonius Vertical Axis Wind Turbine.  It will be rated at 100 watts and cost around $124 to $314 to make, depending on the quality of wind turbine motor you use.

The list of materials you will need to make this VAWT:
  • 5 PVC Tube that are sized 3" x 10'.  Buy them at your local hardware store for around $48.
  • 3 bike wheels that are 12".  (salvage old junky bikes from a garage sale) around $5.
  • Ametek 38 volt turbine motor alternator.  What you need to look out for when getting a wind turbine is the highest voltage for the lowest RPM.  Specifically, you want a motor that will produce 1 volt per every 25 RPM.  Here is a motor buying guide that will let you compare different Ametek motors in order to receive the best one for a homemade windmill.  You can pick up a 38 volt Ametek alternator for around $60.  This cheaper alternator will need to hit at least 500 RPM in order to produce 14.1 volts.
  • Alternatively, you can get a Windblue alternator on ebay for around $250 and it will only need about 200 rpm to reach 14.1 volts.
  • A 1" square piece of plywood or any wood that is 12 inches in diameter.
  • 3 pieces of 2x4 at 12 foot, you can get them from a lumber store for around $11.

Before we get into how to make this VAWT, lets discuss the alternators.  The Ametek is $60 and the Windblue is $250.  Which one should you get?  The answer

How Efficient are Vertical Axis Wind Turbines compared to Horizontal?

Are you looking to build a wind turbine, or to buy a windmill, and you want to know whether it is better to get yourself a vertical axis wind turbine or a conventional horizontal windmill?  It is a good idea to educate yourself on the differences between vertical and horizontal axis wind turbines.  Obviously, you want to get the one that has the best return on investment, whether you will buy a wind turbine or build it yourself.





The challenge when it comes to a wind turbine is to extract energy from the wind.  According to physics, it is impossible for a windmill to exceed 59% efficiency when extracting kinetic power from the wind and converting it into mechanical power.  The remaining 41% of the power must remain in the wind.

Lets cut to the chase!  You don't really want to read a 2000+ word article to discover which one is the best, right?  How about I give you the answer to the question now, then if you are still hungry for more information you can read the math formulas and physics involved explaining just why one is better than the other.

The best type of wind turbine is ...