Dirigible Hung Wind Generator

[paultrafalgar]

Since wind force is much greater at higher altitudes, I was wondering if it would be a viable idea to hang a wind generator from a dirigible (barrage balloon)? It might be an idea to use a vertical axis wind generator, since the engineering would be easier, although vertical axis windmills tend to be less efficient. The power could be lead down the tethering wire and you might consider using hydrogen rather than the much more expensive Helium as the buoyancy fluid since there would be no humans aloft. What do you think?
Here's a British Vertical Axis wind turbine:
http://www.reuk.co.uk/Quiet-Revolution-QR5-VAWT.htm

 

[Lessss]

One of the Guys on the Lions den and also own Discovery channel has a project like you mention underway. they are having issues with their horizontal design and the ballon-mill twisting too much in the wind.

 

[spinningmagnets]

For twisting they might consider two turbines that counter-rotate, either side-by-side or axially. Each performance glitch can have several possible solutions. Would it work? I'm certain it would, and at certain altitudes the wind blows 24-hrs a day.

I'm guessing a big concern would be the tether (and also power-cable) would have to be quite long, and there'd be no guarantee where a malfunctioning balloon would come down. How would the EXTRA-high winds encountered in storms affect the cables? The stronger you make the cables the heavier they are, also the longer you make them (so the balloon is above most storms) the heavier they are.

I'm guessing they'd be most cost effective at reasonably lower heights, away from dense populations, and they should be cabled down when a storm approaches...The Hindenburg aside, with no people on-board, I would use hydrogen.

 

[Drunkskunk]

The other problem is what to fill it with?
helium is in short supply, Hydrogen is volitle and it's atom is so small it can pass through most materials, slowly bleading off from even sealed steel containers.

What about using a High altitude Kite?

 

[paultrafalgar]

That was my first thought, DS, but I preferred the balloon because it stays up, whereas the kite comes down when there is no wind.

 

[Lessss]

http://www.interactivearchitecture.org/flying-wind-turbines.html

 

[dogman dan]

It's a good idea, that just needs more development. The lifting gas is no problem, hydrogen is cheap and can be replaced as needed. One issue is too much wind. Currently the Aerostats that guard the border with tethered balloon based radar have to come down in really bad weather. So they'd be likely to need human attendants just like the aerostats do.

 

[paultrafalgar]

Nice find Lessss, Damn! you can't invent anything new - it's been thought of already!
Dogman, couldn't the balloons just be automatically lowered based on the wind speed?

 

[dogman dan]

Possibly. I just know that there is a crew that runs the radar aerostat nearby, but then that one is Govt run so of course as many jobs as possible. The wind generator aerostats may have different wind requirements, but I still suspect they would need a bit more TLC than a turbine on a pole. Hovever, if the increase in power generated makes that worth the cost of attendants it would not be a problem. It's a good solution for us locally, since the nearby mountains mess up regular wind generation by forcing the wind up off the ground a bit higher most of the year.

 

[paultrafalgar]

Na! Those guys are just watching the radar screens for incoming N.Korean missiles! :wink:

 

[etard]

Haha, that makes me feel safe.

It seems with technology such as that in the Raptor (f-22?) where an airplane can fly itself in spite of the pilot, then the balloon can at least be controlled remotely, from your phone, email, or even sensing hi winds itself and retreating for safer altitudes would be a snap for half the guys on here. I think this is an excellent idea for small scale power production, I even like the kite idea, maybe with a base to land it on, swivel base, and a simple device that reels it in and out depending on string tension. I would love to try this if anybody wants to get a group project going on this.

 

[dogman dan]

Just to clarify, these aerostat radars are looking for little tiny planes carrying drugs, that skulk through canyons below regular ground based radar. They have been around since the Regan era, so by now maybe they could be automated a lot more. It's nice for us balloonists though, we can call them up and get a wind direction and strength report at 1000 feet.

 

[paultrafalgar]

Haha, that makes me feel safe.

It seems with technology such as that in the Raptor (f-22?) where an airplane can fly itself in spite of the pilot, then the balloon can at least be controlled remotely, from your phone, email, or even sensing hi winds itself and retreating for safer altitudes would be a snap for half the guys on here. I think this is an excellent idea for small scale power production, I even like the kite idea, maybe with a base to land it on, swivel base, and a simple device that reels it in and out depending on string tension. I would love to try this if anybody wants to get a group project going on this.

How about filling one or several of those weather balloons with hydrogen and suspending a small commercial wind generator below it (say a 400 Watt one). Tether the beast to the ground and let it go up a couple of hundred feet (whatever the public kite flying law allows for max height). Charge some onboard Lipo and run a search light or camera off it. Or maybe run a small cable down the tethering cord and charge on the ground. What do you think?

 

[dogman dan]

It would be fun to try. You'd need a really good gas bag, UV would quickly ruin regular latex weather balloons. The main issue would be keeping the turbine facing the wind. I have no idea if it would weathervane like normal, or need a more solid mount to function. For starters, you'd need a bigger piece of land than my 1/3 acre.

 

[etard]

Paul,
I really like that idea with the Lipo as a lightweight storage device. I will have to do a search on rcgroup.com to see if there is any of those guys thinking about this... Now what if you used the electricity to heat an element, or even charging the batteries would cause enough heat to act much like a hot air ballon, Dogman? What do you think man, how much heat, balloon volume to support weight, maybe 25 lb. ship plus tether cord... Read the article about Megann, if you used hot air, and did away with the super long power cord with all it's electrical losses the total package would be scalable. The perfect size would be a blimp you carry on your rv, imagine yourself at the beach, you wanna charge the battery on the thing, and the wind is an average 5mph. So you climb up on the roof, inflate your blimp, unreel it out, and go back downstairs and chill 8) Now Dogman, does this sound like something the same guy in breezy Arizona would be interested to do, and if he can do it in the rv, why not at home on his 1/3 acre? I love this idea, it promises to be a truly fun and relatively cheap way to get into windpower. Goin over to see what an rc blimp costs... :wink: Maybe one with a camera, hey Paul?

 

[paultrafalgar]

Etard, generating electricity to generate heat to keep a balloon aloft strike me as thermodynamically daft! Just my intuition. Using the generated electricity to power a camera or charge batteries would just be an interim measure to test the concept. For instance, if you knew the state of charge before you flew it you could measure the state of charge after the thing came to earth to get an idea of how much juice you had generated. Or you could fly your wattsup meter to get a better idea. The camera would be to record that you had achieved it (not to photograph the nubile sunbathers next door!).
Anyway, in the end the idea is to pipe the juice down to the ground. I guess an AC generator would be best and a high voltage, since the down-wire could then be smaller. High tension and hydrogen sounds a bad idea though. Rectify the output and transform down to 12volts (or whatever) to charge batteries.
Dogman, the balloon can have a tail (weather-vane) like those water-pumping wind gennies that you have all over America. That will keep the turbine prop facing into the wind with a swivel link suspending it.

 

[dogman dan]

Lifting with hot air takes a lot of btu's. The balloon has to be huge etc. Model hot air balloons 25 feet tall can bareley lift a couple small propane tanks, like a hand held torch uses. So it would need to be hydrogen or helium. The weight would be signifigant for a small generator, it takes about $3000 worth of helium to get a man in a parachute harness off the ground, about 200 pounds. So maybe only hydrogen would be cheap enough. The generator could be below the balloon so no sparks got to the gas.

 

[Jonathan in Hiram]

To me something like the Roberts Rotorcraft makes a good deal more sense for a bunch of hobbyists, many of whom have experience with RC helicopters.

http://www.skywindpower.com/ww/index.htm

Australian Professor Bryan Roberts has long been convinced that, by application of an appropriate technology, this high altitude wind energy can be captured. He set out to prove that long ago, and has demonstrated that Flying Electric Generator(FEG) technology is practical and should work at high altitudes. This is the "Flying Windmills" technology about which you may have read in publications or on the internet. Competition for tapping this high altitude wind energy is also in development elsewhere in the world, and we welcome that.

 

[paultrafalgar]

Great Find! And here is the IEEE abstract of an article mentioned on that site:
===================================
Harnessing High-Altitude Wind Power
Roberts, B.W.; Shepard, D.H.; Caldeira, K.; Cannon, M.E.; Eccles, D.G.; Grenier, A.J.; Freidin, J.F.
Energy Conversion, IEEE Transactions on
Volume 22, Issue 1, March 2007 Page(s):136 - 144
Digital Object Identifier 10.1109/TEC.2006.889603
Summary:Flying electric generators (FEGs) are proposed to harness kinetic energy in the powerful, persistent high-altitude winds. Average power density can be as high as 20 kW/m2 in an approximately 1000-km-wide band around latitude 30deg in both the hemispheres of the Earth. At 15 000 ft (4600 m) and above, tethered rotorcraft, with four or more rotors mounted on each unit, could give individual rated outputs of up to 40 MW. These aircrafts would be highly controllable and could be flown in arrays, making them a large-scale source of reliable wind power. The aerodynamics, electrics, and control of these craft are described in detail, along with a description of the tether mechanics. A 240 kW craft has been designed to demonstrate the concept at altitude. It is anticipated that large-scale units would make low-cost electricity available for grid supply, for hydrogen production, or for hydro-storage from large-scale generating facilities
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Will cut down global warming by preventing air traffic too!