Theo:
When I want to have a meaningless, nonsensical communication on the web, this is the place to come. Your main thrust seems to be that I was wrong in stating that planets closer to the sun are warmer. I'm just gonna let that remain as-is, and you can go on record that planets closer to the sun are colder.

Hey what "we" need is someone who has any idea what the heck they are even talking about.

 http://www.linkedin.com/pub/khaled-katmawi-sabbagh/31/3a0/926
 <http://www.linkedin.com/pub/khaled-katmawi-sabbagh/31/3a0/926

-And another:

Several organized on 

This just in from a friend - I include it because it fits our topic.

http://www.google.com/patents?id=I7XvAQAAEBAJ&pg=PA11&dq=perpetual+motion+machine&hl=en&sa=X&ei=rXy6T5jQAcLu2gXgroWvCQ&sqi=2&ved=0CEcQ6AEwBg#v=onepage&q=perpetual%20motion%20machine&f=false

As I told him, it's likely to be appreciated here, since it
1) combines Dr. Suess with Rube Goldberg,
2) is drag-based
3) with a pulsating cycle
4) it will never be built (perfect for this list) and
5) avoids simply turning a generator (fits the pattern here),
6) combines other irrelevant machinery (OK now we gotta build a railroad too, just to store the energy - mmm hmmm...)
of their non-steady-state, pulsating system (non-steady-state operation lowers capacity factor while a main reason for AWE is increased capacity factor))
therefore it meets all the qualifications to encourage endless fantasy without progress.

Other than all those factors, it looks like an exciting idea! Hey I had fun looking at it! Maybe it will make someone think of something else a little more viable or even something "in the pocket"!
:)

A thread was already started on that patent: 

...yeah!

 7) it is nothing without Pr.Crackpot's explains

 8) it is the same story of reinvention of wheel for 3000 years

 9) it is the occasion for all Pr.Crackpot yacking on presumed climate change

10) "according to our projected estimate our prototype..."blablah...

 

Maboumba!

 

PierreB

MWR is still going strong.

It'd be nice to hear what they say about optimal parameters for transmitting fluid energy upstream in tensioned structures.

Or the meteorological variations on those optimal parameters.

It may be quite a revelation

Hey Brian:
Together, figuratively, we could be said to all be standing in a circle, looking at a black box, attempting to describe what we think is inside that black box: Nobody knows exactly what form an economical/viable AWE system might take, should it emerge. It's a mystery, so we all speculate.

A glass box, however, is easy to see inside. Everyone knows what's in it. There's no mystery. In the case of motors and generators, designers stand around a glass box: the contents are well-known. There's only one reason anyone stands looking at a glass box speculating what's inside: they are blind or they have their eyes closed. There is no logic to standing around speculating what is in a completely transparent glass box.

In the case of motors used as generators, it works like this:
Open voltage is linear with RPM;
Current is linear with RPM
Power is Voltage x Current
Therefore Power is proportional to RPM squared.
Therefore half the RPM gives 1/4 the power
Therefore dropping your RPM in half means you need 4 x the generator.

The fact that instances can be found that seem to not follow that math exactly, between models, is to be expected - it's only a "rule-of-thumb" and does not try to take into account every aspect of every model of motor. Nevertheless it is, for the most part, accurate, and certainly is the rule-of-thumb recognized by the people who need to use it.

Anyway, I believe that this discussion works best when we treat black boxes like black boxes, and clear boxes like clear boxes. Treating a clear box like a black box makes no sense. I'm not here to debate known facts that are common rules of thumb, things that I use every day, or that can be easily looked up.
:)
Frosted Glass Box? I guess we sometimes deal with glass boxes that have been intentionally obscured.

Doug,

As I said before, what you say is only true if the generator is driving
a passive load. A passive load is something like a water heater that
does not change its resistance in response to the changing generator
voltage.

However, if the generator is charging a battery the situation is very
different. If the generator is not turning fast enough to generate more
than the battery voltage the power is a big fat zero. Once the generator
is turning fast enough to start charging the power increases very
rapidly. The gen and the battery have low internal resistances (to
maintain efficiency) so the generator will experience an effect rather
like hitting a wall. That is why connecting a wind turbine generator
directly to a battery works so well. The turbine spins up under no
resistance until battery charging begins. The battery then acts as a
speed controller.

Pierre's question was what would happen if he designed a generator to
run at half speed. In the battery charging situation, if rotation speed
was the only thing changing then we would have to double the number of
windings in the coils. To keep the copper mass the same we would have to
also decrease the wire cross section area by 2. The result is winding
resistance increases 4 fold.

Ah! you might say, that will decrease the current 4 fold therefore 1/4
the power. That would only be the case if winding resistance was
limiting and if that was the case the generator would have terrible
efficiency. In real generators the winding resistance should be much
lower than the load resistance. Therefore the current should change
little.

The trouble is that keeping the coils cool is usually the limiting
factor and the I2R losses in the coils are the main source of heat. To
keep the I2R losses to what they were before we only need halve the
current. Therefore when cooling is the limiting factor power is
proportional to speed.

If cooling was not limiting and the winding resistance was low enough,
we could in fact get a zero power loss penalty for halving the speed.

So, as you can see, there is no single right answer that covers all
situations. Modern designers absolutely have to develop computer models
to find the optimum solution for their particular situation. I started
several years ago and I built a small generator which performed
according to the results from my spreadsheet. To get better results I
needed to get a better map of the magnetic field strength. That requires
finite element modelling and I have just not had time to get to grips
with the free programs now available.

For as much detail on this as you care to take in there is an excellent
thesis by Maxime Roger Joseph Dubois called "Optimized permanent magnet
generator topologies for direct-drive wind turbines" that can be
downloaded. I am not going to bother looking up where I got it from
because it is 270 pages of highly technical electrical engineering only
relevant to those designing generators.

Robert.

Doug,

My experience is that when you hit a persistent problem
you can either apply brute force to it (eg. build bigger generators) or
you can swot up more on the theory and find an optimal solution. The
fact that you have had so many generators burn out tells me that you
never got around to developing a comprehensive computer model telling
you what is going on with them. To burn out 1 is a lesson. To burn out
several shows that there is a missing link in your chain of logic.

It is magnetic hysteresis that creates the heat. If the iron is sent
beyond saturation then the hysteresis rapidly increases. However, it is
always there which is why Hugh Piggot went for air-core generators so
that the turbines could spin up under minimal resistance to start
catching the wind. Air-core machines can be way more efficient (98% has
been demonstrated) than iron-core ones (usually <90% unless very big). I
am in the process of working out if Visventis would be better of with
air or iron cores; or pancake or a more square format.

Robert.

I would like a flying car too! Maybe something like this one
http://www.flixxy.com/pal-v-flying-car.htm

Rotors get more efficient as they get bigger. Moller went for 6 for
reliability and safety but using 1 like most helicopters do might have
given him more success.

You do not need More storage for yo-yo type groundgens. All electrical
wind power systems require either grid connection or local energy
storage. The short-term power requirements of the retraction phase will
make little difference to most energy storage systems.

Robert.

More info in the post

http://www.kitegen.com/en/2012/05/22/the-success-of-the-recent-open-day-sunday-13th-of-may/

here the direct link to the youtube video

http://goo.gl/0A9sY

All the Best

Stefano

My first thought when I was it was that Joe F. and the gang must already know about it.
I guess I missed that one the first time around.
Sorry about that Joe!
:)
While I think it's "a goofy idea", it does have some interesting aspects that might lead to something better...
- Doug S.

Some related matters, perhaps: 

Yeah that explains why you've built one generator and I've built many for myself and others. Wanna know how I design generators? Get in the car and go visit people who know what components are likely to be available at low cost in large numbers for many years, and shoot from the hip and design a generator around those components that "looks right" compared to all the other alternators I have seen/dissected.

(Internet? The kiss of death for design and product development. Spend all day musing over AliBaba ads... boring!) treating a glass box like a black box "Yes, hello China? I'd like to order one..."

Ask real human beings and get a real answer.

The result is a low-cost, repeatable product that matches the performance of most custom-designed alternators. And the beauty of it is you can keep on making as many as you want, never doing any math to figure out one thing except adjusting how many turns of what gauge wire can fit in your slots for any voltage at any RPM.

Anyway, power as a square function of RPM remains in force with battery-charging systems. The voltage can climb to double if the battery bank is small and the batteries will explode as the inside ceiling of the old test vehicle will attest. Without a charge controller, you can ruin a small battery bank. Because batteries "clamp the voltage" (or attempt to) you end up trading off increased voltage for increased current. That is why battery-charging systems are easier to burn out than grid-tied.

The problem comes in when the wind gets strong with its cubic power function due to the volumetric flowrate. Thinking your battery voltage offers overspeed protection might work for one or two MPH, but the turbine will quickly overcome the batteries' and generator's ability to slow it and it will "run away", often cooking not only the generator but the batteries and all associated electronics. This often happens with grid-tie systems too.

Hugh tells me his generators will never make as much power as mine since he uses no iron. His approach is all about smooth operation and home-buildability. He's looking for consistent charging and reliability whereas I'm building hot-rods. Grandpa isn't going to burn out the engine in his econo-box sedan - if you wanna see a lot of blown engines, go to a race track! Racing technology filters eventually to better performance in Grandpa's sedan.

It was recognized by the ancients who applied animal skins to their draft-animal merry-go-round mills, that constant operation in a circle was an improvement over a pulsating or retracting cycle. Nothing has changed since then. Drag-based turbines with retraction cycles is the lowest of the low, with regard to conceptual understanding of wind energy. The yo-yo kite defines the dumbest possible approach to AWE. Nonetheless, sometimes dumb technology can be appropriate for some uses under some conditions. Proof is in the pudding. Wind energy is not immune from the need to have a useful product. Theories and prototypes are great but not marketable per se, at least to end users.
That's why so many idiot new turbines sell "territories" instead of turbines, or at least they used to before they all ended up in jail...
:O...

Note: that thing on top of the vehicle is a wind turbine.
Ask:
1) why doesn't its rotor have more blades?
2) would adding more blades to the rotor increase performance?

Yeah how come it doesn't have 22 blades like a farm windmill?
Oh probably something cultural... or hard to understand...

Hey how come this glass box looks black to me?
Help I'm blind! Can we have a list for people who can't see through glass?

piezoelectric nanogenerator    http://fand.kaist.ac.kr/Attach/NCG.pdf

I think that kites excel at producing gross movement, so this is not applicable directly.  However, if they can get it to respond to heat, like the Brownian motion, it might put us all out of business by circumventing the Second Law.

AWES homes?   

Video 

It might be a good flutter sensor, although a microphone would probably be sufficient.  If it is dirt cheap and feather-light, it might generate useful power by fluttering, but then we are back to the conductive tether debate.  

What might a "conducting" tether of a kite system conduct? 

The ground/sea impact of AWES is very low.However tether's length is the
radius of a huge area.As mobile installation,AWES can be considered as
dangerous for ship traffic or for fishermen,or for occupied ground
zone,unless the said area is forbidden,with the economic
consequences.Perhaps for HAWE a semi-immovable semi-airborne system
could be a solution.

PierreB

Mitigating the tether safety-economic challenges: 

Perhaps the "forbidden" area could be used if kites fly from a rather high and constant angle to free an enough sure and identified part of area for ships within the occupied zone.

 

PierreB

Very nice!

Doug wrote on 21.5.2012:
These disscussions may be at cross-purposes and are certainly off-topic, but
they are not meaningless. Two posts ago you were enjoying them. I think your
present reaction is because you have lost the argument.

My main thrust is to counteract your wrong statements and faulty reasoning in
this and all threads regarding climate change. You keep getting your facts wrong
and attack anyone who disputes this.

Regarding the surface temperature of planets: you brought this up on 13th May:

Of course planets which are closer to the sun are warmer than those which are
further away, if the conditions are equal. The point is that planets which have
an atmosphere are much warmer than those without. The 800 degrees of Venus are
precisely so high because of its high CO2 greenhouse atmosphere, a fact which
you dispute. The greenhouse effect is so effective, that the average surface of
Venus is even hotter than the *hot* parts of Mercury, which is closer to the sun.

Cheers, Theo

Doug wrote:
...
I expect this is OK as rule of thumb. However in general (neglecting losses)
current is not linear with RPM, but rather with torque and is independent of
RPM. However as changing the RPM generally also changes the loading, it will
give this effect. Also, the continuous power is often limited by temperature and
a lower RPM will ofter mean that the motor or generator is not cooled as well,
which will limit the current. Unfortunately motor manufacturers often only
publish data for the design voltage. What you really need is several graphs at
different voltages and then see if your application still fits within acceptable
efficiency limits.

Cheers, Theo

Certainly,the closer the angle of flight can be to 90 the better, I suppose•

---

 

Hey Theo:
I stopped because you proved my point - thanks! :).
My point was that promoting "global warming" requires a departure from the facts.
You neatly illustrated the point:
I point out that simple 3rd-grade-level fact that planets closer to the sun are hotter. I noted that this fact is conveniently avoided by warming advocates.
Your response was to try to "frost the glass" by finding some way to seemingly negate that simple fact. Rather than acknowledge that I at least had a point, and include it - take it into account, you immediately search for a complication - a single instance that would seem to make such a simple observation that planets closer to the sun are hotter - wrong.
This is exactly what I mean when I was the advocates of these theories are allergic to any facts. When you can see their responses trying to intentionally obfuscate simple facts by grasping for exceptions, and promoting the exceptions as the rule, you can see what is taking place is not a good-spirited collaboration to make the box transparent, but instead a desperate attempt to refrost a section of the box, lest it become transparent. :)

Theo:
No need to frost another glass box here. We don't need to act like blind men trying to describe an elephant by touching only one part - this can be simply looked up! I suggest you lower your fact-shield! Of course we can always find slight modifications and wiggle-room in any rule-of-thumb.
I think truly for the level of discussion possible here, we're safe acknowledging the simple, well-known fact, that anyone can look up in books on building your own wind turbine (as just one source) that motors and generators produce power in proportion to RPM squared. Have fun documenting the exceptions - I gotta get out there and build another generator.
:)

Yes,if it was possible.To be vertical is an advantage of conventional wind tower.

 

PierreB

Doug wrote:
...

I am glad we can close this off-topic for now. However I would like to record
here that it is the other way around. Nobody is promoting global warming: it is
happening. However climate change sceptics go into the denial of facts (e.g.
Doug in this thread) either because they are influenced or bought by the fossil
fuel lobby including many political parties and governments, or in order to
justify their own actions which are killing people every single day.

Of course it could also simply be trolling - I can't tell.

Theo Schmidt

Doug wrote:
This is simply not true as a general statement for motors and generators as Doug
is doing. It depends entirely on the loading, as Robert pointed out.

The case of the maximum power of wind turbines is entirely different as we are
here talking about wind power converted by the turbine blades. The electrical
characterics of the generator have little to do with this if we assume that the
loading is optimally regulated.

The RPM of an efficent turbine is roughly proportional to the wind speed over
most of the operating range. The maximum force and hence torque which the
turbine blades can produce depends mainly on the square of the speed. Power is
force times speed or torque times RPM. Therefore theoretically the power
increases mainly with the *cube* of the speed or RPM. See also e.g.
http://www.wind-power-program.com/turbine_characteristics.htm

However either side of the best operating point there are increased losses both
at the low and high RPM side. At low wind speeds these are low Reynolds number
(less force on the blades), friction and lower generator efficiency. At high
wind speeds the generator will also be outside its optimal efficiency and in any
case quickly reach its maximum power, so the RPM has to be limited, also for
safety and sometimes noise reasons. At some stage the turbine has to be
deregulated (power drops) or even shut down.

This is all shown nicely in these graphs:
http://blog.silverford.com/wp-content/uploads/2010/03/wes-80-kw-power-curve1.jpg
http://blog.silverford.com/wp-content/uploads/2010/03/endurance-50kw-wind-turbine-power-curve.jpg
http://www.windturbines-china.com/wp-content/uploads/2012/01/5000Watt-Vertical-Axis-Wind-Turbine-Power-Curve.jpg

You will see a small range where the increase in power approaches the ideal cube
law, but mostly it is less. Therefore a square law curve fit is a good
approximation over a somewhat larger range. It is certainly a good rule of thumb
as Doug points out.

Cheers, Theo Schmidt

Ha ha ha Joe - very artistic presentation of our former genius. Do you get the feeling that you're watching aspects of a future lost art slipping away?
Future generations will watch films like this in an endless search for why people used to be "smart", asking "what happened"?
Like in the movie Idiocracy - wake today's biggest dummy from a coma, and he'll be a genius compared to the future masses, with even their common sense having been slowly disassembled by bureaucracy. At this rate our future will be populated by helpless blobs that can be told anything. Wait I think we might already be there... or have we ever been anywhere else?
Anyway thanks for this fun movie - enough to make one think. But don't you think showing someone like a Dave S. a movie like this is sort of like trying to put out a housefire with gasoline? Combining these turning gears with the turning gears in Dave S. brain could result in some broken gear teeth. Dave S. I hope you are OK!
:)

Pls let us be less personal in making our submissions.

---

 

Wind gradient - Wikipedia, the free encyclopedia

Wind speed gradient is by far lower offshore than onshore.So the profit of HAWE is lesser offshore:at an altitude of 1000 m energy can be only twice energy at 100 m.So is the expense and the weight of a long tether needed?And onshore (offshore probably also) safety requirements make very difficult a GW-scale installation (too much km² of reserved zone).

I have studied applications for small AWES.Market possibilities seem weak.

On the other hand AWES seem to have very good possibilities for middle-scale,under FAA limits (AWES is not necessarily HAWE) , particulary where grid is not available,in islands for example,for prevailing winds at places kites are above the seaside. Other point, see also recycling old paraglidings.

PierreB 

Click through for full document. 

I've just seen Doug's patent 6616402 for the first time. That is a hell of a
patent! I'm sure you have answered this question on this list many times before,
Doug, but I am only able to read a fraction of the messages. Have you built some
of these, published any specs and photos and are any for sale, hardware ond/or
plans?

(The patent show more or less vertical axis generators sprouting a bendy rod
full of turbines, which bends and rotates in the wind. About 50 variations and
even a wind turbine boat with both a bendy turbine and a bendy propeller!)

Cheers, Theo