Slow Chat III

Love it. Think 120 m/s winds at 200 km altitude

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I’m talking about Makani’s wing which flies at 50 m/s. The wind is then 12 or 13 m/s, no more.

However, in continuous use, the secondary turbines would be put under severe strain, experiencing an apparent wind of 50 m/s and a corresponding TSR (150-200 m/s ?). I wonder how long they would last.

https://www.linkedin.com/feed/update/urn:li:activity:7255178983212732417/

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Well anyone truly interested in wind energy, which probably doesn’t include anyone here, has had many experiences of burning out generators. The reasons are twofold:

  1. When the wind gets strong, the turbine will exceed the power it was designed for. this can burn out a generator pretty fast.
  2. Sustained high winds can slowly cook a generator, until a “hot spot” begins to develop anywhere in the stator windings. Once the wires begin to heat up in any small area, the electrical resistance of the hot wires is increased, resulting in an unstoppable “runaway” heating episode that cooks the generator very quickly. Upon later dissection, one can see where the problem started, and how it spread.

Very few initial attempts at wind energy provide enough generator for the amount of power encountered in strong winds, especially sustained strong winds. Almost every new attempt at producing wind energy systems encounters this limitation. It usually means you need
a) a bigger generator with more copper
b) better overspeed protection for the turbine itself.

If you haven’t built and run a lot of wind turbines, you wouldn’t know about any of this, but it seems likely to me that projects like Makani, and maybe the kite-reelers, may have encountered generator overheating, and that may be one reason why they always inexplicably give up, and never have anything in regular production.

Overall, there are many potential failure points in wind energy, and probably all the more so for new types of systems. Of course, most drag-based turbines, like Savonius, will not be making too much power, and are unlikely to burn out any generators, since they are unlikely to ever produce more power than expected - almost always far less. But if you do have something that makes power, look out, because what was your biggest goal will quickly turn into your biggest problem! :slight_smile:

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Hi Doug, this is a plausible explain.

Very interesting.

In numerous comments @dougselsam indicates a lack of knowledge about the current traditional wind energy field. In my opinion this observation could be useful when accompanied by more technical considerations in relation to the AWE methods considered, even if they are obvious to wind energy professionals.

As a start his recent post:

Questions might be, among numerous ones:

Fly-gens: overheating of the generators due to too much power concentration on the aloft turbines, in relation to their low weight, and also the cyclical irregularity of power.

Ground-gen reeling (yo-yo): intermittent power, motor use alternating with generator use, leading to wear of the generator and other equipment.

More generally, what were the errors that led to dead ends, errors that would not occur or not to this extent in traditional wind power?

Hi Pierre:
To enjoy success n any field of endeavor, we tend to “stand on the shoulders of the giants who have come before us”.

Whether you wanted to advance the field of physics, chemistry, motivational psychology, or just design the next winning race car, you would be well-advised to gain actual experience, in the actual field as currently practiced, before pretending to advance it, especially with the degree of disdain, dismissal, and outright disrespect aimed at conventional wind turbines by AWE wannabes.

We’ve all heard the wise words from France, that a design is perfected when there is nothing left to remove. In wannabe wind energy, the urge is always to add something to “improve” ideas that are already lacking due to unnecessary and misguided, “extra” features. It’s really just one more case of “the definition of insanity being to keep doing the same thing and expecting different results.” :slight_smile:

Hi Doug, your experience with wind turbines naturally marks you as the expert on wind turbines as they exist.

As AWE is struggling to take off, to say the least, it would be good to open a topic on this subject, in order to examine in detail what is wrong with the various projects in relation to what would be rejected in regular wind energy field.

For this topic I would proposed a title like below.

“Question to Doug: what are the AWE problems that could be overcome with a better knowledge of regular wind power?”

The same at night:

Of course there are numerous small AWES that can charge a phone.

I love your actual, working AWE experiments Pierre, but I was talking about the previous subject, was it called Tiiros? From Switzerland? “Send us your money!
We did renderings!” (Yes but do you have a new test site in Ireland? A “Human Resources Department”? Have you rented office space?) More noise from the armchair geniuses of the world? All I saw was renderings


Anyway, lighting LEDS, while quite valid as proof or some output, is pretty much the bare minimum, lowest level of proof possible. (Well, then again there was that self-winding watch
) Let’s say LEDs are the bare minimum for demonstrating some small, unmeasured amount of electrical power production.

I did not see a phone being charged. I only saw LEDs being lighted up. That does not quite imply sufficient power, voltage, and enabling electronics, to actually charge a phone. :slight_smile:

To do this, a voltage regulator would have to be added, which is a game-changer.

For potential users, either they must want to fly the kite every time they want to make a call, or they must have automated steering and pay a lot. Ultimately the user will prefer to recharge their mobile phone as they usually do.

My son did phone charging (x6) with the scouts, using a daisy AWES on jamboree in Austria when he was about 14 years old

I say AWES in the loosest sense here because they tied the top end up to a tree

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Amazing how things change when we step back and look at the big picture, rather than being driven exclusively by bumper-sticker, slogan-based “reasoning”!

New study uncovers major problem with fuel touted as a ‘bridge’ to cleaner future: ‘Substantially worse than coal’

Goes to show any «light emission» plan is risky. We [the world] should skip these and spend our focus on reneawble solutions.

The LNG kind of plans usually stem from a greenwashing effort by some oil company

These are hypotheses which are of no interest and have nothing to do with the topic I opened. We discuss what exists, not things that don’t take into account this:

Leo Goldstein’s quote already stated this:

I took up his statement which is sufficient in itself, by adding the elements of intermittency already discussed.

I don’t think it’s appropriate to look at your wild assumptions of a generator with 10 or 50 tethers. That doesn’t interest me.

But if you think this could be a game-changer, build one of your contraptions and disprove my conclusion.

Otherwise try to post more constructive things. THANKS.

Challenges of single line pumping AWES would be the intermittent generation, the oversized generator needed and so on. Multiple line pumping AWES would address that and more, possibly or likely reducing the total cost, assembly, and cost of maintenance for example. Not needing 50 shipping containers or 50 generators or being able to use larger drums (if that reduces line wear) for example might add up, so it’s an interesting analysis to do.

My concept might be the best yet described, graciously provided to give a possible basis for analysis, but whatever it might turn out to look like multiple line AWES is the natural and obvious progression to single line AWES and is on topic in the topic you started, whether you are interested in analyzing it or not. Granted it is difficult to do the analysis without knowing what the architectures might look like, so the topic might be premature. You’d really need BOMs of the different designs and a lot more information to be able to do the analysis and have it be of use.

For a long time Dave Santos is investigating networked kites which use multiple line AWES. This may interest you.

Your topic isn’t on kite networks and my concept also isn’t so this is kind of a non sequitur reply. The kites are explicitly not networked together so that they can fly out of phase with the other kites to get non-intermittent generation and can fly in an optimized path. You could connect multiple kites to the single lines though.

Some concepts in that topic might be scientifically interesting, but the treatment of them isn’t good. My single comment:

The topic seems to be on static networks, I would find networks flying crosswind more interesting, either physically connected or not.

This topic is more applicable I think: Swarm Robotics

Some clues about existing wind turbines on https://www.quora.com/What-is-the-typical-cost-for-the-generator-of-a-wind-turbine-direct-drive-and-geared :

General Rules:

  • The higher the rated capacity the lower the cost per kW.

We might think that it would be the same for the pumping (yo-yo) AWES generator(s). Thus a single large generator would be less expensive than ten or more smaller generators totaling the same power as the single large generator.

But in all cases the low speed of a third of the wind speed of the tether motion during the reel-out phase would remain a handicap compared to existing wind turbines, as stated.

It would perhaps be different if the single generator for several AWES would total much greater power than the generator of the largest existing wind turbines.

But, in the same comment:

  • The whole turbine assembly—the thing that gets mounted on the tower—represents a surprisingly small fraction of total system cost which is composed of the turbine assembly, support structure, distribution/collector wiring and control system. The actual generator represents a fraction of that fraction of total cost.

In the same way and in an even more accentuated way, it would be necessary to imagine the feasibility (of which the calculation of frictions) and the costs of intermediate stations, pulleys and all the infrastructure, and the elements that are linked to the compensation of the phase shift (different reel-in and reel-out phases according to AWES) to connect to the single large generator.

Finally, to calculate costs we would need to know if a system like this would work in a real world. It is therefore up to the designer to do all this work and validate the installation, before integrating it into the
Economical assessment of the scalability of the ground station in pumping mode.

On another subject: it seems that Advanced Kite Networks is about a description of a crosswind kite network, but the given elements do not allow to have a clear idea of how the Power Take Off (PTO) occurs.