Windmill on a Kite

There was a company that issued a press release about a year ago (give or take a decade - my memory isn't what it used to be) about their design to mount spinning windmills on large hydrogen-filled balloons. Kind of like your kite idea, and it wouldn't need constant watching nor come crashing down when the wind was still. It was also I think intended for power generation at remote locations. Unfortunately I can't remember the name of the company. Maybe a Google search would find it.

I seem to recall it was discussed at length here in the CR4 forums. Some among us tossed out the idea that these balloon-mills might collect rainwater and use a portion of the electricity generated onboard to create hydrogen via electrolysis, keeping it aloft longer.

Commercial tethered kit wind turbine designs as well as tethered balloon designs have been discussed here on CR4 (by myself and others). I don't have the links handy, you could try doing a search for "wind turbine" or "tethered turbine".

What about a pump? You could pump water up a line.

Don't remember this being considered, but unfortunitely I doubt it would work as the pump would have to be big and heavy to suck up 500 feet of water.

Hi Jack

You can only suck 10m (33') of water or you are sucking a vacuum. You can pump above 14.7 PSI i.e the pump must be part way up the string, preferably at the bottom.

If you make something that will suck a vacuum I'll invest all my savings in it.

Tony

Even when the line is primed (ie- already pre-filled full of liquid)?

You might be able to design a turbine kite that flew connected to the ground by wire instead of string and transmitted small power to ground. It would be interesting to determine what materials a standard crossform with rag tail design tethered by wire would generate dc static to ground of some use. I am under the impression that during WWII, if not earlier, kites were used to loft AM Shortwave Antennas in certain situations. For precedent and kite applications for anything other than a child's March afternoon, you might look at how kites have been used for some practical purpose in the past. Thanks for the question. I've been a bit bored this week.

visited Wikepedia on your subject. Lots of interesting stuff.

A good link = A good answer. Just this once.

I've thought through this one before too. The problem with placing the generator of the kite is weight. Here's the best apparatus I've come up with.

A kite and several thousand feet of cord is attached to a spool. The spool on one end is connected to a constant torque take-up motor. The take-up motor acts as a never ending spring trying to reel in the kite. The other end of the spool is clutched and geared up to an induction motor/generator.

The control system then closes a contactor on the induction motor/generator as the kite is pulled up by wind. As the kite spools out, the transmission pulls the induction motor above its slip and a small amount of energy is pushed back onto the line. When the wind subsides, a simple tension monitor such as a limit switch, starts the constant torque motor which take up the slack. When the wind picks up again, the kite spools out and turns the generator again.

An alternative could use a flywheel PMG to charge low voltage batteries.

As with most alternative energy projects. They sound good until you put it on paper, then the reality of economics sets in.

Awesone, I'll buy it! The kids around the block used to install two or three GEM razor blades on their kites and figth one another once high upthere. Very Funny Times Those!

Your idea do sounds real good tell you the true. Hey why not. Now as you mentioned yes a kite do have a lot of pull for real. So this force may be put to work some how I believe. Gosh! now you get me wondering. How about having some strong kite that revolve like an engine some how with such air forces upthere, hey! Like a turbo fan someway? There we go that's it; a "TurboGenFlyingUnit" equipt with few electronics sensors that allow modulation and flying control somehow. From there we'll migth hook up few 'power increasing modules' to it circuits that step-up as demands call for. Hey Buddies Not Bad! Not Bad at All!

Or as the "TurboGenFlyingUnit" rotate upthere it will turn a pulley enougth to move a generator on the buildings roof that will supply some juice for lites, etc. Excellent!

Hook that Puppy-Up,

MC

what about a piezoelectric generator to take advantage of the buffeting tension load on the string too... and make the kite out of lightweight solar cells... just don't fly it into the power lines!

Yes, several companies are working on this. Among them Makani and Sky WindPower. Magenn already has a helium based rotating balloon system based upon the Magnus effect for lower altitudes. Makani has received funds from Google and is fairly secretive about their work. A lot of Makani's folks have windsurfing related experience. Professor Ockels at Delf U in the Netherlands continues work on his laddermill design. Sky Windpower is actively prototyping flying electric generators targeting altitudes of 12,000-30,000 feet based upon Australian professor, Bryan Roberts' work.

And here are those links that were previously discussed on CR4

http://www.wired.com/science/discoveries/news/2006/10/71908

http://www.kitegen.com/index_en.html

http://www.magenn.com/about.php

As we know from parasailing, a kite can support a lot of weight. I have seen a beautiful panoramic photograph of San Francisco after the earthquake/fire. The negative was about 4 feet across, and the camera was huge, carried aloft several hundred feet by a kite on a boat in the bay.

There are electrically powered model airplanes. I'm sure one could tether one and fly it like a kite. (model gliders are launched that way) The wind would rotate the propeller, and the motor might work like a generator and charge the battery. Wind driven generators are common on sail boats; why not on kites?

basic flight math.

lift = weight

Thrust = drag

In a kite, things are complicated by the vector of the string holding the kite stationary but these principles apply.

Thrust is the force of the wind against the drag and the horizontal force of the string.

wieght is the wieght of the kite and the perpendicular force of the string.

If a turbine or windmill is added to the kite, the drag will increase with the amount of work extracted from the wind, and everything gets heavier and less efficient for the flight of the kite.

I would bet if you ran the numbers, the extracted energy will NOT amount to much before the kite is unflyable.

Rumor is that the Kitegen effort fell by the wayside last year, though not for technical reasons.

For more on wind power math, capacity factor, tethers

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

TIME's best inventions of 2008 #35 Airborne Wind Power

http://www.time.com/time/video/?bcpid=1485842900&bctid=1887840886

and about the vast high altitude wind resource

http://www.makanipower.com/home.html

http://dge.stanford.edu/DGE/carcher/high_altitude/ha_atlas.pdf

Solar resources are best used in lower latitudes, while high altitude wind resources are super for the middle latitudes where capacity factors can be three or more times that of the best ground and off shore wind.

I found these on YouTube Search using the term "Windmill on a kite"
http://www.youtube.com/results?search_type=&search_query=Windmill+on+a+kite&aq=f
The search term "Kite Windmill" only produced three videos, all included with several more under the link above. Some of these are fanciful toys - some are worth a serious look.

Windmill Kite Patent

http://www.patentstorm.us/patents/6781254/claims.html

Here's a video of the "Wright Brothers" version design flying and generating a little electricity in the mid 80s, the basis for Roberts' patent.

http://www.youtube.com/watch?v=gExAQq2VzgQ

Below is a link to the laddermill concept.

http://www.ockels.nl/

I was quite taken with a link supplied above. The Magnus Helium Blimp system is not far from going commercial it would appear.

Essentially it's a semi-ridged pressurized helium bag tethered by a transverse axle with collapsible vanes that open and close depending on their rotational orientation to the wind. The whole shebang rotates around the transverse axle and lift is increased as the rotational speed picks up due to the lower air pressure induced by higher speed against the airflow over the top, thus as the wind picks up it rotates faster overcoming and offsetting the induced parasitic drag of the electrical cable/tether line. It's a marvelous innovation – right up there with McReady's perpetual flying spy wing powered by solar wind; one never hears about that anymore because it became a black operation a year ago or so (read it's operational now).

Somewhere are a website that has scaled down prototype multi-wing tethered kites carrying generators in the center of mass for each wing – with extended shafts trailing the wing(s) with variable pitch propeller vanes parasitically pulling energy out of the air blowing bye; using the induced drag to help stabilize the stacked wing system; and running the electrical energy down its tether line (Nano Cable will greatly increase the efficiency one supposes). As a retired old class, I extended Easy Riser hang glider pilot, I'd be very much delighted to see this concept being turned into something beyond pure thinking man's aero-sport. I'd like someone to put the link to this tethered kite system here or perhaps I'll find it again and add it to this very interesting thread.

Does anyone have any particulars about Mr. Craven's Deep Ocean Cold Water Thermal Generators https://www.wired.com/wired/archive/13.06/craven.html purportedly to be installed at the US naval base on the Indian Ocean island of Diego Garcia?... and their so-called Hurricane Generators using deep ocean cold water to make electric power, almost free of cost. Chilled water cooling to attain both freshwater and air conditioning is a no brainer, in addition.

I posted this on another thread devoted to favorite inventions, which on considerations should more properly have been posted here.

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I have to admit that my favorite "Invention" is the wind-turbine such as posted above in this thread. However wind turbine style and type and construction systems are so variable that it's hard to pin down which is my personal fave, albeit the tethered, pressurized helium blimps floating 25 miles high or so, making the scene of late, are my turbines of choice just now... There is a practical reason that I admire them and favor their deployment - they are too high to create the slow motion shutter effect that adversely affects not a few humans and animals and the lack of discernible noise "down wind" of their location that could affect most living entities on or near the ground. Being so high they are exposed to sustained, strong winds and miss most storm problems. Thunder storms in the vicinity would necessitate their being winched down, most likely on occasion.

There is one aspect of wind-turbines that has always dismayed me. When Turbo-mavens post raves about the latest number of mega-watts now on stream - I always wince. My small, quiet horizontal dynamo that charges all my power tool batteries does almost all of its work at night. I know that this is not anecdotal for my wind generator system since this urban area is in a zone two wind rating and 3 or 4 is the minimum for viable commercial applications.

The wind in our neck of the woods often is too light during sometimes extended times of the day to make it turn, at all. That happens to be why EXXON and Valero out in west Texas are making a pile of money - the wind-turbines out there are often times motionless during the day when electric demand is highest. But at night the Catabatic winds are predictably robust and because the electric load is so light during late night and there is no adequate grid to carry their power away to far off cities - they have gobs of surplus electricity that they auction off at penny's on the dollar to the oil pump jack owners that happen to be a stones throw away, thus making expensive, formerly too deep to pump oil available for primo profits. They just shut the jacks down during the day which are during higher rate periods of time when local commercial and private demand is highest.

I would like to see a standard made that adjusts for mean power output of mega-watt wind turbine farms. While we in the States are demanding truth in bail out and truth in banking, etc. I'd also like the truth about how much energy wind-farms actually produce at 11 am to 6 pm during summer when electrical demand is peaked and at its highest in our air conditioned, power hungry state(s) and country(s); where it is universally NORMAL for winds to be at their lightest velocities during nighttime and often nil to none existent during daylight hours.

We are being asked to fund state bonds to build a national electric grid - so just how viable will the need for distribution from far off wind farms be, when the demand for electricity is stretched to the limit during daytime peak loads in urban areas?

Many cities have experienced brown outs and rolling black outs because the problem of grid capacity is still an art, not a science. Natural Gas powered jet turbines in inner cities are growing old and too expensive to cover the short fall in urban areas, in a growing number of cases. Dependence on wind power from remote locations needs to factor in the greatly reduced mega-watt capacity one will actually get from them during the day in the real world. In truth I've wondered why wind farms don't power massive systems of water pumps at night to pump hydro-water in a lower holding lake, up into a higher holding lake and then use the hydro energy during peak load daylight hours; over and over again.

These are questions outside my expertise, but I hope some one or more of your bright minds can take up the challenge. Anyone?

Don't know about how all the wind farms connected in a grid system total up during these hours, but ground and off-shore based wind power is generally best in the morning and evening hours as the sun is rising and setting.

Examples of how various renewable energy sources can work together: Oroville's Edward Hyatt Power Plant at the base of the impressive Oroville Dam in northern California releases a 24 hour supply of water in the high usage time frame you mentioned so that all the power generation happens when it is needed most. This plant is part of the Oroville -Thermalito Hydro Generation/Pumping plant system that operates as a peaker plant.

Obviously, solar power is best in the 11 to 2 pm timeframe and only a daytime thing.

Burning Biomass though it still released carbon dioxide is carbon neutral. I've heard that generation can be ramped up at appropriate hours for some of these as well.

It's all about getting various sources to work together.

Tinker65,

If you haven't already You might enjoy watching Discovery Channel's "Infinite Winds" that shows some of the development and test phases for Magenn's MARS craft, though Magenn isn't named during the show.

http://dsc.discovery.com/tv/project-earth/timelines/winds.html

Regarding lack of wind power during the day, this is only at ground level. At high altitudes, the jet stream helps planes fly east 24/7, while hindering them flying west. Five to ten miles up is where the wind energy is that Sky WindPower and Makani want to convert to electricity. A link where you can see winds at altitude at one location for the last 24 hours - updated every 30 minutes -

http://www.mstrf.eclipse.co.uk/PLOTS_LATEST-24-HOURS/nerc-mstrf-radar-mst_capel-dewi_latest-24-hours_cartesian.png

Solar power including solar thermal power should provide a lot of daytime power at ground level.

Extra wind and solar power could be used to produce hydrogen. The National Renewable Resources Laboratory has a Wind-to-Hydrogen project.

http://www.nrel.gov/hydrogen/proj_wind_hydrogen.html

You have referred to what is known as pumped storage. Extra energy is already used at hydro power dams sometimes to pump water back up into the reservoir for later energy release. Water is not readily available at many of the best wind locations. One place where it is is the Tehachapi Pass where megawatts of wind power are used to move eater over these mountains to supply much of southern California that does not get its water from the Colorado River.

CAES or compressed air storage in under ground caverns is another way to store excess energy for later use.

Once there are a lot of plug-in electric vehicles attached to a smart grid, their batteries which are most often charged at night could use that extra night time power. Plug-in Electric Vehicles using and storing energy on the grid could stabilize the inconsistent supplies of wind and solar power.

Big commercial wind farms typically perform 1 to 2 year meteorological site surveys before leasing lands. They need to know how much power can be produced over a year in order to make power supply agreements with utilities. Utilities ask wind providers on a daily basis how much power and when they expect it to be available the following day.

One of the unstated reasons why T. Boone Pickens might love wind and natural gas together as he has a huge interest in natural gas is that natural gas power plants can be fired up quickly to produce peak power or make power when sources like the wind are less available.

Several studies have been done that show that in a smart distributed power grid having a lot of wind and solar power, that power can be balanced as the wind tends to blow at different times in different areas. The result is effectively baseload power production.

Thank you for the links. This one: http://www.nrel.gov/hydrogen/proj_wind_hydrogen.html was an excellent diversion to look into. However, I'm one of those pessimists that always picture what our cities and our planet will look like if we become converts to Hydrogen Energy. Our imagined future environment would look like a scene out of Blade Runner staring Harrison Ford in which downpours several time per day are the price for abundant hydrogen energy in a future in which we might divert away from the current carbon energy economic models. I'm a staunch advocate of stored none carbon energy, powered by none-carbon energy gathering systems, as a result. Thanks for the link, none the less.

Stacked flying wings with generator/turbine motors - now that, I can relate to.

Like many, I'm still a sceptic about the new rave called "Free Energy." Until the means by which that system "gains" energy in excess of the amount it takes to power it is explained - I'll watch with great interest but that's about it for now: http://www.youtube.com/watch?v=F2cZGYXYjJE&feature=related

I'm not a believer in completely free energy either as that reminds me of perpetual motion, which stretches the imagination a bit too much. It is necessary to use energy to build anything that captures energy from a renewable resource. For a long while, building solar cells (from mining silicon to manufacturing to shipping to installation) used more CO2 than they would have saved. We are still using a lot of fossil fuels to build the rest of our renewable resource energy economy.

I'm also not enamored with regards to a Hydrogen energy economy, seeing it as only one of many types of storage for energy, but not as a major source for operating vehicles or for burning in power plants. Thanks for the Blade Runner image. It's a good one to keep in mind so that we don't go too far down the hydrogen highway.

Speaking of wings with motor-generators, it was just reported that Saul Griffith of Makani gave a talk a Harvard in which he divulged more about what Makani is doing to capture energy from high altitude winds.

http://www.news.harvard.edu/gazette/2009/03.05/11-kite.html

Windflyer,

Thanks for all the great links. Most are now in my Fav's Folder and some on my website, too. Here's one that precipitated out whilst I was looking about: http://www.nerc.ac.uk/ for those of a more science dominated engineering bent.

Tinker65,

Thank you for sharing and stimulating thoughtful discussion around wind energy and for the links.

Recently I saw a college student designed collapsible ground based wind turbine working in a wind tunnel that is a vertical design that like the Magenn Helium MARS operates on the Magnus effect. It is intended to be portable so that it can be used in multiple locations and be stored when not in use to avoid theft, which is a common issue on an island where there is a need to raise water stored in underground tanks that is collected when it rains.

One could arguably label me a wind turbine maven. Below are posts that address pro's and con's for this burgeoning electric generation industry. Not all of what are posted on them are pro-wind turbine by their nature. Like all alternative energy industries, the engineering and the economic consequences of wind turbines and wind farms are still just coming into the light. Their health impacts, once focused on their bird hazard potential, are now expanded to human health issues, as well. As a result, I have dropped tower mounted turbines as a alternative electric generation solution and now favor low speed, high torque vertical or horizontal, high aspect ratio slat blade types (similar to blower wheels in air conditioning systems).

R.E., Wind Turbine Experiences http://cr4.globalspec.com/thread/30077
Comment #11 Wind turbine visual shuttering problems and down wind sounds Reference video link: http://www.youtube.com/philbloomstein
The YouTuber's recommendation is minimum 3,000 feet (3/5ths of a mile) minimum set back. No recommendation for visual shuttering problems set back. One should have some sort of structure or vegetation block their view of turbine shadows especially at sun up and sun down when their shadows can reach quite far, one would assume.

According to the thread named "Are Wind Turbines Hazardous to Your Health?" Industrial wind machines may cause ringing in the ears (tinnitus). r.e., http://cr4.globalspec.com/blogentry/8351

Addison, Texas has let bids for water tower powered by wind turbines. Yesterday I started a new thread dedicated to improvements on their out of the start gate design concept. I believe that great idea could stand some improvements such as installing water turbine generators at its base, to scavenge electric energy when the water is flowing back into the city water system; and a horizontal generator powered by low speed, high torque (quiet) vanes rotating around the entire outside of the wine-glass goblet shaped water storage tank. Here is a link to that thread.

http://cr4.globalspec.com/thread/35864

Thanks for posting all this information. A friend of mine was telling me about how he liked the vertical turbine type design, but I discouraged him. I'm in the HVAC industry and just don't see a squirrel cage as being very effect. I guess I'm going to have to rethink this design, and maybe eat my words with my friend. We have a friend that has a farm and they are trying to get off the grid so we have been thinking of some designs to help him do that. I love your idea about the vanes around the water tower. I'm a bit of an artist as well and that could be a very beautiful as well as a practical design. If you don't mind I would like to look into using something like this with my friend. He has an old windmill without the blades. We might be able to rig up a turbine around his tower and put a water tank at the top. You could do some really cool artwork with those blades. I'm really excited about this idea. Let me know if it is all right to use it and thank you for opening my eyes.

Hi Fishpipe, Im working on a wind turbine design and I was wondering if you knew anything about duct design,with regard to air volumes and presures?

I'm no engineer but you can't be in the business for 30 years and not learn a few things. What are you trying to do, I will see if I can help. If I can't then I know the engineers that do know the answers. Give me as much detail as you can. If you want to you can reach me at fishpipes@cox.net

Fishpipes, you responed to my post #31, I could not get through using your email, mine is spacecannon@san.rr.com .

Finally, some information on what Makani is doing. Their CEO is a truly brilliant inventor committed to making a difference on an individual as well as a corporate level.

http://www.ted.com/index.php/talks/saul_griffith_on_kites_as_the_future_of_renewable_energy.html

Also worth watching, not about wind, but it will certainly stimulate creative thinking.

http://www.ted.com/index.php/talks/saul_griffith_on_everyday_inventions.html

Yes! Many kiters have thought of just that and much more. We mount many kinds of kite motors, flipper-wings, flutter wings, wingMills, line-laundry propellers, torsion-producing balloons, rotary-wing generators, ... and more. A group of serious workers have been gathering in two Internet places; they are growing an extensive open-source web site and an open-source forum. There is energetic competition among a score of enticing methods.

There is large invitation to engineers of many specialties to lend their talents to rapid development of energy kite systems to reach energy price points that will win benefits for earth's health.

http://EnergyKiteSystems.net

and the related forum is easily subscribed to there.

Nearly anyone's specialty talent will have a niche place to play in the challenges involved.

A large distinction has to do whether the energy is for doing direct immediate work or store energy in a number of ways. Another large distinction is whether the generator of electricity is in the air or placed on the ground or water surface. There are small and large and huge systems being seriously developed. Kites and kytoons (kite that is also a balloon) are used in systems of one kite or many. Join in the serious fun.

See the methods page. See the current researchers page.

Lift,

Joe Faust