Airfoil vs Legacy

Airfoil Generator vs Legacy VAWT Issues

Vertical Axis Wind Turbines (VAWT) have been around for more than 50 years and unfortunately, they have had some outrageous claims made about them by their respective promoters. Here we look at some of those claims and some of the feedback about the typical VAWT; and how our Airfoil Generator compares.   

Blade fatigue:  Long, unsupported blades of some wind turbine designs allow for a lot of twisting and flexing  within the blades themselves. This is particularly true for Darrieus-style VAWT’s and all HAWT’s. All materials are fatigued by repeated flexion that will result ultimately in their failure. Knowing that the blades of those vertical and horizontal wind turbines will need to be replaced adds a cost-of-ownership expenditure and a scheduled maintenance event to these generators. However, the Airfoil Generator’s blades are well supported and flex much less, and as a result, are not as susceptible to material fatigue, failure, and replacement.

Design Compromise of Blades:  It has been pointed out that on a vertical wind power generator, half the time the blade is moving in the direction of the wind, and the other half of the time it is moving against the wind. So what we see as results is only the net, that is, power produced going with the wind minus power lost coming back around against the wind to start over. This truth has made many designers compromise their blade design so as to reduce the drag of moving against the wind. However, in our design the blades of our turbine are only exposed to open air flow in one direction, allowing us to shape them optimally because we do not have to design-in a compromise to our blade shape for the back-wind side. 

Mounts on buildings: Many promoters of micro and even some small VAWT’s have promoted that they can be mounted to existing buildings.  This is a horrible idea, and it has been proven such many times over. Whole chapters of books have been dedicated to this topic, talking about the turbulence caused by buildings, the reduction in air flow caused by buildings and trees, and more. Keep in mind that the energy content of the wind is the cube (the third power) of the average wind speed; for example if the wind speed is twice as high it contains 23 or 2 x 2 x 2 = eight times as much energy. You WANT your generator to be where the good wind is. For best results, we recommend a 30’ to 50’ tower be used depending on the site.  

Self-starting:  Some say that the ability of any WPG to rotate in very light winds means very little as there is almost no energy to be extracted from light winds, and this is true. However, that does not negate all the value in being a self-starting device that can operate in light winds. The real benefit of operating in light winds and being a self-starting mechanism is in the reduced complexity, cost, and maintenance when you do not have to have starter motors and/or starter systems and circuitry on your WPG just to get it going.

“VAWT Designs are more material intensive than Horizontal axis designs”: Maybe, depending on which designs you are comparing. But when you take into account the complete 20 or 25 year service life of the generator, and add in all the regular blade replacements they require, a design such as ours that does not require regular blade  replacement is a lot less material intensive and costly.

How “green” is your wind turbine?  If you consider the whole life of your wind turbine including replacement blades or rotors, it might not be as green as you’d hoped.  Add to that the environmental impact of disposal of these parts. Even if the old blades are recycled instead of buried, the amount of electrical energy required to cut up and process these parts into their recyclable materials is staggering – and directly in contrast to the environmental benefits they produce. We are proud to offer the Airfoil Generator as a greener design, not requiring regular rotor or blade replacement.  And isn’t helping the environment the whole reason for going “green”?