Don't like windmills? What about a windbelt?

Daox · 11-06-08, 11:00 AM

Looks like a belt that vibrates in the wind used to produce electricity. Very interesting. I'd love to play with the idea myself. I wonder how noisy it is?

Windbelt Micro-wind, 10 Times Cheaper Wind Energy!! - Green Building Blog - Jetson Green

The maker's website is here:

Humdinger Wind Energy

cmittle · 11-06-08, 01:16 PM

This is a very interesting idea. I'd like to see if this ever takes off. It might work well in some nice markets like residential areas that don't get snow. Of course I highly doubt they will produce enough to run a house but they'd be good for charging drill batteries and other small DIY type applications.

GenKreton · 11-09-08, 01:55 PM

I'd like to see some performance maps under a variety of wind conditions. He seems to have built one that matches it's natural frequency with that of excitation provided by his fan. If you have wind that isn't hitting a natural frequency then it's very probable this thing produces almost no power - even if the wind is faster than that of a natural frequency (of which there can be many).

cmittle · 11-10-08, 08:06 AM

This is probably true. I wonder if you could create a small device that would attach to this and if the wind is blowing but generating below some threshold it would touch the string creating another node and keep moving (slowly) until it sees another spike in power output, indicating another natural frequency. If done on one end of the unit this would in most cases stop output from that end, but maybe two of these devices could be put in the middle and spread outward independently (they could have the same displacement too which would probably work just fine as the windspeed should be the same on such a short distance) until the natural frequency (or a multiple of) is found again.

Daox · 11-10-08, 09:23 AM

There is some discussion in the blog comments about what you describe GenKreton. The argument against this is that this is aeroelastic flutter, not resonance. I didn't read the wiki, but I assume this means that the band doesn't need a specific frequency to flutter.

GenKreton · 11-11-08, 05:24 PM

I wasn't too familiar with the term so I read the wiki and it had this to say

"Flutter is a self-starting and potentially destructive vibration where aerodynamic forces on an object couple with a structure's natural mode of vibration to produce rapid periodic motion. Flutter can occur in any object within a strong fluid flow, under the conditions that a positive feedback occurs between the structure's natural vibration and the aerodynamic forces. That is, that the vibrational movement of the object increases an aerodynamic load which in turn drives the object to move further. If the energy during the period of aerodynamic excitation is larger than the natural damping of the system, the level of vibration will increase. The vibration levels can thus build up and are only limited when the aerodynamic or mechanical damping of the object match the energy input, this often results in large amplitudes and can lead to rapid failure."

It went on to say that "One famous example of flutter phenomena is the collapse of Galloping Gertie, the original Tacoma Narrows Bridge."

This means that flutter is the exact same thing as resonance.

One thing that would be possible to change the natural frequency would be a system that tuned the length of the belt to change the natural frequencies but this would also mean moving the generators since I believe he had one at each side.

Interesting but I fear it's applications are limited in it's current form.

11-06-08, 11:00 AM	#1
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Don't like windmills? What about a windbelt? Looks like a belt that vibrates in the wind used to produce electricity. Very interesting. I'd love to play with the idea myself. I wonder how noisy it is? Windbelt Micro-wind, 10 Times Cheaper Wind Energy!! - Green Building Blog - Jetson Green The maker's website is here: Humdinger Wind Energy __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

11-10-08, 09:23 AM	#5
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	There is some discussion in the blog comments about what you describe GenKreton. The argument against this is that this is aeroelastic flutter, not resonance. I didn't read the wiki, but I assume this means that the band doesn't need a specific frequency to flutter. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

11-06-08, 01:16 PM	#2
cmittle Helper EcoRenovator Join Date: Oct 2008 Location: Sioux Falls, SD Posts: 56 Thanks: 0 Thanked 1 Time in 1 Post	This is a very interesting idea. I'd like to see if this ever takes off. It might work well in some nice markets like residential areas that don't get snow. Of course I highly doubt they will produce enough to run a house but they'd be good for charging drill batteries and other small DIY type applications.

11-09-08, 01:55 PM	#3
GenKreton Lurking Renovator Join Date: Sep 2008 Location: Cambridge, MA Posts: 29 Thanks: 0 Thanked 0 Times in 0 Posts	I'd like to see some performance maps under a variety of wind conditions. He seems to have built one that matches it's natural frequency with that of excitation provided by his fan. If you have wind that isn't hitting a natural frequency then it's very probable this thing produces almost no power - even if the wind is faster than that of a natural frequency (of which there can be many).

11-10-08, 08:06 AM	#4
cmittle Helper EcoRenovator Join Date: Oct 2008 Location: Sioux Falls, SD Posts: 56 Thanks: 0 Thanked 1 Time in 1 Post	This is probably true. I wonder if you could create a small device that would attach to this and if the wind is blowing but generating below some threshold it would touch the string creating another node and keep moving (slowly) until it sees another spike in power output, indicating another natural frequency. If done on one end of the unit this would in most cases stop output from that end, but maybe two of these devices could be put in the middle and spread outward independently (they could have the same displacement too which would probably work just fine as the windspeed should be the same on such a short distance) until the natural frequency (or a multiple of) is found again.

11-11-08, 05:24 PM	#6
GenKreton Lurking Renovator Join Date: Sep 2008 Location: Cambridge, MA Posts: 29 Thanks: 0 Thanked 0 Times in 0 Posts	I wasn't too familiar with the term so I read the wiki and it had this to say "Flutter is a self-starting and potentially destructive vibration where aerodynamic forces on an object couple with a structure's natural mode of vibration to produce rapid periodic motion. Flutter can occur in any object within a strong fluid flow, under the conditions that a positive feedback occurs between the structure's natural vibration and the aerodynamic forces. That is, that the vibrational movement of the object increases an aerodynamic load which in turn drives the object to move further. If the energy during the period of aerodynamic excitation is larger than the natural damping of the system, the level of vibration will increase. The vibration levels can thus build up and are only limited when the aerodynamic or mechanical damping of the object match the energy input, this often results in large amplitudes and can lead to rapid failure." It went on to say that "One famous example of flutter phenomena is the collapse of Galloping Gertie, the original Tacoma Narrows Bridge." This means that flutter is the exact same thing as resonance. One thing that would be possible to change the natural frequency would be a system that tuned the length of the belt to change the natural frequencies but this would also mean moving the generators since I believe he had one at each side. Interesting but I fear it's applications are limited in it's current form.