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Would a rooftop turbine vent be capable of turning a generator to power part of a home?


Picture of Would a rooftop turbine vent be capable of turning  a generator to power part of a home?
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dpalmer21 year ago
Ive been thinking about using one of these Edmonds Roof Ventilators with a 500W PMG. Both pictured below.

I think I could couple (via a Belt Drive etc..) the generator to a Certified Grid Tie Inverter and export engergy (I already have a 4.2 kw Solar Array feeding into the grid).

I think this is doable... there has been some other investigations as well which suggest with modifications it can be done!

www.ipcbee.com/vol12/35-C10031.pdf
Screenshot from 2012-09-01 18:55:39.pngScreenshot from 2012-09-01 18:56:05.pngScreenshot from 2012-09-01 19:04:43.png500W.jpg
rmyers71 year ago
I have 2 rooftop turbines on my home.... on the gulf coast of FL ..... I have watched my turbines and I get spin with less than 2 MPH winds .... it can be still outside and my turbines are spinning slowly ......

I have been wondering for several years, WHY I can't do something to convert this into energy ... Would love some ideas if any??
JmaesMcD2 years ago
I just wanted to say that this HAS ALREADY BEEN PROVEN TO WORK! there are two companies already producing this idea. the first is http://Solar & WindBy.Design.com/ in northern California, the other is http://www.rooftopwind.biz/ in Chicago, IL. both of these companies have patent rights to their designs. sorry guys! and they are installing them both on Residential, Industrial, Commercial Rooftops as well as Pole Mounted Installations. check them out.
frollard3 years ago
The whirleygig roof vents? No - they barely extract enough energy from the wind to do their own jobs -- extract hot air from the roof of the house.

The tradeoff is technically, yes, you can extract power. That power wouldn't be 1/100th the energy required to run a light bulb.

Essentially, newton was right. You get out what you put in, and you can't get more than that. The vent fan doesn't pull much power from the air, so it doesn't HAVE much power to give you.
taftinni (author)  frollard3 years ago
I'm not sure if I beleive that. I'm not discrediting you, I just haven't seen one in operation up close. I understand that they are made to vent hot, stale air from closets and such. Could it be modified to spin more freely, or something? Put some magnets and a coil on the inside, not all the framework and heavy material of a typical motor. How fast exactly do they spin? I may have to go find one and obsereve.
You are forgetting some critical factors, such as friction and weight. If you were to design an assembly, mounted exactly as a roof vent is, the additional weight of a coil and the friction involved to turn the spindle would be prohibitive. I agree with frollard on this, there just isn't enough energy in expelling the heat to generate the power you are looking for.

Assume you could move the turbine vent to generate electricity, then you would likely need a few, just like wind turbines (installed in groups, usually not just one). Applying the same metrics you have say 4-5 vents on one roof. The addition of more vents directly effects the amount of air transferred through any one, decreasing it's effectiveness (as the air is drawn from a limited supply, the attic).

But, this site is all about making new paths on stuff, so maybe there's something there that we can't think of conceptually. The only way you're going to be satisfied is to wire up a roof vent and try it out.
Good luck!
I agree with the idea that a roof vent could generate powere as a top up to a battery bank as well as PV panels.
I have gone as afar as designing and making a prototype with an engineering friend. I can see this sitting on or near the ridge where it will be happy to use any turbulating airflow, which is much better than a wind turbine vibrating the house. I have laid heavy guage 12volt cables when converting the roof to a gable end and just now need to source a good motor.
I intend to use RC Plane technology as you can get a good monitor for rpm, voltage wattage and temperature etcc.. that can be downloadedonto a computer.
Can add some pictures soon. It spins very easily and with a brushless motor and one way diode, i am sure it will generate some power

Squirrel - England
I have always wanted to build this as well.

I understand all the additional drag and not much energy gained from the wind, but consider all the warm air.

I'm in Texas, the vents on my house are flying around as fast as possible nearly 24 hours a day 300+ days a year. Regardless of the wind, the hot air propelling these fans alone has to have some significant generating power.

I'm no engineer, but I am a CPA and it doesn't take many numbers to make this feasable in a warm climate and 150 plus degree attic ventilating.

Squirrel10 get-er done and keep me posted as I'd like to add about 5 of these to my house.
Right. They rest on a pin-bearing usually, since it's low friction. They are designed to move in the slightest breeze. Only trouble is, a slight breeze has virtually no valuable energy once you count the losses in the system extracting said energy.

If its heavy and strong, it won't spin. Since its lightweight, it spins, but again only because theres so little total energy.

This is not a 'told-you-so' moment or statament -- Honestly, please please try it., and I beg you to prove me wrong. There is a lot of education value in trying something like this (whether it works or not), but remember you get energy out what you put in - and these just don't have that much energy.

For example -- get a floor fan, look at the wattage -- say...50-100 watts. Now turn the fan on and feel how much wind that is at pointe blank. Note how much that is for 50+ watts. Now imagine how useful 50 watts is...now imagine how much wind that would be outside to get that wind speed. *this isn't factoring in efficiency, just an example. there is a reason that wind turbines in a proper generating environment are big -- it's the only feasable way to get usable energy out.
Kiteman3 years ago
As they are, no.

However, you could replace them with vertical-axis turbines that could be used to trickle-charge a battery bank.

How useful that would be depends on the size and number of the vents you replace, how windy it is in your location, the size of the batteries you are trying to charge, and the power demands you are putting on those batteries.

I would suggest that such a system would be most useful for a [remote] location you do not use all the time, and does not have a huge power demand, such as a hunting lodge, pleasure cruiser, garden shed or caravan.

lemonie3 years ago

The use of pictures is not the best, but like others have said - no, you'd want a different turbine for useful power generation.
See what's over on the right under RELATED ----------------------------------------->

L
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