Interesting Concept in Wind Energy

Here’s a concept that I thought readers would find interesting. The air that comes out of ducts in industrial and commercial buildings has a certain amount of kinetic energy that is wasted.  Believe it or not, the air that is pumped out of an opening five feet in diameter is moving about 10 MPH, which translates to a little over a kilowatt.  Here’s a system that captures about 40% of that energy.

At first blush, it appears to violate the laws of physics, and, if you inserted it in-line with the duct, it certainly would; you’d be claiming to remove more energy with the turbine than you expended with the fan.  In this case, however, the presence of the turbine doesn’t slow down the fan.

Big deal, you might say.  You build a wind turbine to generate 500 watts?  Isn’t it going to take half a century to pay for itself?  Not necessarily.  Consider a two-bladed system and a generator, all perfectly engineered for this exact case: wind that doesn’t change direction, blowing 24 hours a day—at the precise same speed.  There are huge opportunities for engineering optimization here.

I’m guessing that the typical electricity customer will save about $800 per year per turbine.  If the cost of the system can be low enough, it’s potentially interesting.