wind chute turbine

[bug bit]

i found the site for the wind chute power turbine

love the idea, it will work perfect for the fish house.

no blades to walk into after a few beers...

i have everything sort of scaled and figured out, just have to put one together and see  how much power i can get to turn the alternator..

14. inch x 6 inch high for the turbine works best with the calculations i have put together.
    
23. inch wide X 14inch high and 14 inch deep on the chute and a 6 1/4 inch tunnel through the blades.
    
    

sure hope it works...

made a prototype out of cardboard and it really spins in front of the window fan.

think it will power 3 deep cycle batteries?

http://www.i4at.org/lib2/windturb.htm

[johnlm]

My guess is you might get 20W at most out of a design like that with the size you are thinking in a 10 - 15mph wind, maybe less.  But then I may be wrong.  Sure would be great if you got alot more and posted the results as it might be a useful approach for some people.  

[wooferhound]

That reminds me of Electric_Ed's Idea of shrouding the drag side of a Saninous rotor like in his picture I'm borrowing here.

and introduceed in this story

http://www.fieldlines.com/story/2003/6/17/73839/3388

[pexring]

Bug bit,

I too am interesting in your results.  What's your timeline for giving this project a whirl?  

In looking at the link you posted, why couldn't a person just connect the turbine to the top of the alternator and skip the belts & pulleys.  It would also be interesting to know whether varying the size of the intake would affect the wind speed.  

Mark    

[bug bit]

i am way behind schedule because it ia hard to work on it and fish at the same time.

i am hoping a couple of weeks to have it set up portable beside the ice house while we fish.

[bug bit]

i don't think there will be enough power or speed without overdriving the alternator once it starts to charge. but i could be wrong

[wdyasq]

http://www.anotherpower.com/gallery/energy-stuff-and-more/foots_cutting_edge_mill_design

Might predate that drawing ... not sure

Ron

[finnsawyer]

Why not turn the chute into a funnel and mount a horizontal mill at the small end?  You'll get greater rpms to start with.

[johnlm]

Bug Bit,  Sorry if I sound a bit skeptical here (it was part of my job in another time) but I would be a bit cautious about the implied expectations of the article you are referencing when building this. Just trying to give you some food for thought before you invest too much time and energy in this setup. From what I recall looking over the article briefly: First of all the article states they do not have the exact dimensional specifications which leaves it up to you to size the thing which you have apparently done.  I think to be able to crank a stock GM alternator (which they seem to strangly express no substitutions to a 61 A model then call out a 37A model on the drawing) fast enough to get up to 14V charging you have to get the alternator at least to around 700 - 800 RPM with the field runing full bore at 12-14 V. The type of impeller this shows has an effective TSR of around 1 meaning the impeller is moving the same speed as the airflow going past it.  This type of design is attempting to increase the air speed by reducing a given cross sectional area into a smaller area thus increasing the speed.  The scale of the diagram kind of implies about a 5:1 area reduction but obviously this is left up to the user to supply their own dimensions for the inlet area size  and turbine area.  I believe there is some limitations as to how much you can try to reduce the area before you start getting a stalled wavefront of air in front of the inlet which just causes the air to go around the outside of the inlet. With that in mind, if I understand the approx dimensions you are using (and make a few asumptions) you have an impeller that is has at most a 1 foot diameter and maybe 0.5 ft cross sectional area to the oncoming airflow. (correct me if Im wrong about this). And the inlet size you are thinking has around 4.5 sq ft.  If you calculate the power potential of the 4.5 ft sq inlet at say 10 mph it come out to around 14 watts.  And this is the therotical maximum you could get without any other losses or inefficiencies.  This amount of power is not even enough to get a GM alternator rotating if the field is turned on and running at 12V. and this is not even accounting for any other losses such as the pully system (maybe 85-90%), the inneffeciency of that type of impeller which might be only around 15% and the other losses associated with trying to compress the air through the chute.  Moral of the story here is to get enough power with this design to charge 3 deep cycle batteries  in any reasonable time frame you would have to scale it up to at least 100 sq ft on the inlet.  Even at that Im skeptical that Ive not taken some other factors into consideration that make my guess too low.  Windstuff Ed has done alot of work in this type of area with these types of approaches and likely could give a better answer.  If it were that easy to convert the linear flowrate of air to a higher linearflow rate by just compressing down its cross sectional area and gain the advantage of the cubic function of air speed verses the squared factor of area one would expect to see it being done all the time.

Regards

Johnlm

Johnlm

[bob g]

while conceptually this might work, there are some considerations that aren't well covered in the web reference.

first is the chute area itself.

they are purporting to get more air and velocity by the use of the chute, it is commonly understood by engineers in the field of flow dynamics that the angle of the shoot has to be less than 7 degrees, this would make the shoot very long to gain much.

another problem is while the shoot should accellerate and build pressure, it cannot with the impellor slowing down the airflow.

would be interesting to see one built, but i wouldnt expect any real power out of it, perhaps 20 watts as previously posted

bob g

[wooferhound]

Yes I'm seeing a that the air is funneled into the turbine but also notice that there is a funnel on the output which would provide a vacuum on the downwind side of the turbine.