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Rainbow wind wheel power

Unidirectional rainbow-wind-wheels connected to alternators
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A one meter rainbow wind-wheel can make about 300 watts.

There's a problem that people don't want to install large and clunky (and expensive) wind turbines, even in industrial areas.

In comes the rainbow wind-wheel power. Simply connect 50 of them along your wall. They don't turn to face the wind, they are static, but they work well because of the "ground effect" of the wall. Since millions of them will be sold, their price will be dirt cheap (its a bike dynamo and a simple plastic wind wheel).

You'll be making 15 kw for a very low cost. Connect them to batteries and an inverter, and you get quite a good tariff from the electric company. No heavy installation, almost no hassle! And if it flies off the building, almost no damage is done, because each one hardly weighs anything.

Its nice and colorful. And it makes almost no sound. As opposed to the noisy mini wind turbine from Hong Kong. This one is a stand alone turbine, so there is practically no sound at all. (See links)

pashute, Jun 24 2013

rather than this http://www.treehugg...-city-dwellers.html
[pashute, Jun 24 2013]

which sounds like this http://www.motorwav...files/airplane1.wmv
[pashute, Jun 24 2013]

Use this http://www.youtube....watch?v=8D00Iq8FcEA
[pashute, Jun 24 2013]

[link]






       any ramifications?   

       I'm writing this because I'm actually investing in a prototype. Your thoughts?
pashute, Jun 25 2013
  

       I question the 15kW, and the "very low cost". Unless they are geared together and turning a single turbine, even a $20 turbine is a thousand bucks for fifty of them. Tack in another few bucks a piece for the wheel, and maybe 5-10 for structure and power transmission.   

       Also, while you gain some wind speed from airflow over the building, you lose more to drag over the building. Get about 15-20 ft above it and that changes a bit, but as always, the higher the better with turbines.   

       I'm not saying it isn't viable if you happen to be in a high wind area, or have a building that rises significantly above the surrounding terrain (natural or artificial), just that I'd take those numbers with a grain of salt.
MechE, Jun 25 2013
  

       You probably mean alternator/dynamo rather than turbine.   

       A 15 kw solar panel system costs in Israel, about $80K. Most of the cost is the solar panels, and about 15% goes on the construction and a DC to AC inverter for producing on-grid electricity. So the generation system (the panels) is about $60K!!   

       The wheel (turbine) will cost 5 dollars each. The alternator with internal gear, bought in bulk from China (where its manufactured anyway) will cost at most $80 each. Give another $15 for infrastructure and installment, you get 50 x $100 = $5000. One twelfth of what the pv costs!!   

       And an equivalent 15kw wind turbine tower costs $7,500 (on Alibaba) for the turbine+generator, and $10,000 for construction+pole. Typically companies sell systems like this at double and triple the price!   

       So its still at least a third of the price.
pashute, Jun 25 2013
  

       What's the average wind speed in your area, and what's the efficiency of the generator?   

       As an additional factor, what's the lifespan of the alternator, and ideally the wheel itself. (If it's plastic in a high sunlight environment, it's not going to last all that long, even with UV stabilizers).
MechE, Jun 25 2013
  

       Using the best averages I can find for Israel (Ben Gurion and Haifa airports), I find a best average wind speed of 8mph. For a 1m diameter turbine, that's only going to produce (at most) about 79W/turbine with a 100% efficient turbine. You do a bit better if you take the average power production, since it goes up as the square of wind speed, so short periods at higher wind speeds produce more, but it's still not good.   

       So I make it more like 100-150 turbines to get up to 15kW. That's going to put it in range of the full sized turbine you were talking about, but again, unless you live in a particularly windy area, you aren't going to get faceplate ratings.
MechE, Jun 25 2013
  

       Also, are you sure your solar prices are current? That seems high. I can find the panels here in the US, retail, for $23k (total for 15kW), microinverters (one per panel) for another 8k.   

       If you don't have a roof or similar structure to mount them on, then yes installation will add cost, but not that much for a near ground installation.
MechE, Jun 25 2013
  

       Hang on a second. This is loopy. But first the [mfd]. As I understand it, the essence of the idea is lots of small wind turbines. But the first link shows lots of small wind turbines. So I'm missing the novelty here.   

       Anyway, on to the loopery. First, noise - is there any indication that 100 of these will be quieter than a single 15kW turbine? Second, in what way do they benefit from the "ground effect of the wall". Third, is it honestly likely that it will be cheaper to make 100 sets of small blades and 100 small generators, and wire them all together, and provide the regulation necessary to prevent the spinning ones from just turning the other ones into electric fans?   

       And finally, are you planning to mount these on top of the wall, or attached to its face? (If the latter, they will receive no wind, whatever direction it's blowing from.)   

       And more finally, why the comparison with photovoltaics?   

       And even more finally, do you really want to look at 100 visually obtrusive brightly coloured spinning wheels 24/7?
MaxwellBuchanan, Jun 25 2013
  

       I think by "ground effect" he means the fact that while rough terrain or buildings slow the overall wind speed in an area, right at the roof-line or corners you see some increase in speed (relative to that slowed speed).   

       I'll admit that I don't agree with the statement that these will work particularly well as a result, and none of my calculations above take that into account. Unless you have a truly prevailing wind direction, you are probably going to need to double to triple the numbers I mentioned, since for any wind direction, half your turbines won't intercept any (on the edge parallel to the wind, and a quarter (on the trailing roof line) will intercept less.   

       And of course that ignores the interference of one turbine with it's neighbor, which will tend to reduce the speed of the wind intercepted at a given point.   

       As far as the mark, I would suggest a mark for expiry, since micro-wind is WKTE, but I took this to be a request for information about actually making such an installation.
MechE, Jun 25 2013
  

       I was really directing it to [MB]'s comment. You're right that in practical terms probably all your turbines generate some power, but the net result is roughly equivalent to having half of them parallel to the wind, and half perpendicular.
MechE, Jun 25 2013
  

       and all of them up against a wall? Seriously, the energy available to a discoidal rotor stuck to a wall is minuscule. The only wind will be parallel to the wall, which will not be captured with any significant efficiency by something that rotates in the plane of the wall.   

       Given that [pashute] is a "Mathematition", a few numbers wouldn't go amiss.
MaxwellBuchanan, Jun 25 2013
  

       The common version is along either the edge or ridge of the roof, not flat up against the wall. I assumed that was what he meant.
MechE, Jun 25 2013
  

       Fair enough.
MaxwellBuchanan, Jun 26 2013
  

       Max, I never said it makes less noise than a turbine. A well designed turbine does not make much noise, and from my experience, the rainbows make a soft sound similar to the flutter of leaves, not something people would be annoyed of.   

       I DID say that it makes less noise than mini-power system. Please look at their website and linked videos. The noise comes from the multiple turbines connected to each other MECHANICALLY. There are other videos on their site where it is even more apparent. Browse it and you'll see. In my idea there is no mechanical connection.   

       Also, please notice it is listed under BUSINESS and not Science:Energy, because it is not a mechanical invention, it is a novel setup and location, or more correctly a "new system".   

       And PV is relevant, because PV and wind are payed with a tariff by electric companies around the world, as renewable energy. In Israel, currently only PV gets installed, and almost no wind installations, although contrary to what MechE wrote we have places with scorching winds. About that later.   

       MechE. First thanks for your time and excellent points!   

       The proof is in the facts. I have had some along my wall, and some on the roof. Surprisingly, the ones on the wall turned at times better than the ones high up. There's a buildup of pressure.   

       Did you ever walk near the corner of tall buildings? As a religious Jew my Kipa (skull-cap) went flying every time I came to work, in the Jerusalem Tower building 25 years ago. The gust of wind was only along the wall. Of course I don't mean flat against the wall!   

       And yes, there are many malls that put up wind swirls and small flags that flutter and turn constantly. They could also have advertising revealed when turning.   

       The scientific textbooks claim there's too much turbulence there and therefore it works less efficiently. There are numerous cases where generalizations like that have been proven wrong. Its worth the try.   

       (Just recently I read of swallow tails, being studied for ages as an aerodynamic price paid for male extravagance similar to the peacock tail, and hindering the swallows flight, but found to be an aerodynamic mechanism for high speed extreme turns).   

       Those are the PV prices here. A company of course pays less, but so will a company making these.   

       Maintenance: So the turbines will be changed once in two years. I still think the price is negligible. And because its nice to look at, will be paid for gladly. (perhaps some ornaments will added). The brushless alternators/dynamos and continuous magnetic gears have a 20 year guarantee.   

       Winds: For "some reason" downplayed by many, Israel has prevalent and strong winds in places. In Efrat there is a hill with pine trees that grow parallel to the ground. And doors on the wind side had to be moved away. In my town, Bet Shemesh, I was at a synagogue discussing installation of various systems, in the summertime, with less winds. We were not thinking of wind energy, but when he took me to a porch that leads to the roof, the door had been thrown open and off its hinges, an hour before. And the building curator said it happens constantly. In the Golan I was told at a school that no wind system I devise will stand the winds, since a half ton water tank had been blown from the ground, and landed on the roof of a two story building, in a common winter day.   

       As a young man of 19, I remember watching in awe as a "sail" wind tower invented by Alexander Zarchin was torn to peaces and sent flying hundreds of meters, in a wind storm. I wonder if anybody ever recorded the remains or the tower itself. I never found any material about it. I was the only person outside at the time.   

       Since (almost) nobody here really believes in co- existence anymore, it may sound foolish, but the truth is that a common Jewish-Arab wind project would be great for everybody.   

       Of course prevalent winds are in areas where Druze, Jews and Arabs live in close proximity: They reach 8 and 10 m/sec which is double your numbers. Gilboa (Maale Gilboa, Meirav), the Gallilee mountains (eg. upper Nazareth, Daburiah, Manarra, Safed), Carmel (Ein Hud, Usfia, Daliat El Karmel), Judea (Halhul, Hanokdim, Tekoa, Efrat, Otniel, Susya), Samaria (you can't stand up in the winter at the archaeological site of the Shilo tabernacle), and the Negev mountains (where not even army camps have been established).   

       But a good and constant breeze is available in Tel Aviv (along the coast, much stronger than at Ben Gurion). - And a 15kw system, never produces 15 kw.   

       Bottom line: IMHO worth the try. I hear the problems expected.
pashute, Jun 26 2013
  

       Well, fair dos then, and kudos for trying it.
MaxwellBuchanan, Jun 26 2013
  
      
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