Hi Gordon. Not sure to whom you refer when you use the word “our”.
As one of the original founders of the AWE movement:
https://www.popsci.com/scitech/article/2008-05/ten-times-turbine/
I beg to differ with that opinion.
My definition of cross-wind power is what direction the moving, working, power-producing surfaces travel relative to the wind.
Of course, we’ve spent 12 years on the old forum arguing almost exclusively over word definitions, often to a completely unreasonable level bordering on, or fully entrenched in, complete insanity. At some point it doesn’t really matter what labels anyone wants to put on something. It matters what it does. Words are only tools we use in our attempts to represent reality, not reality itself. So at some point there is no use in pretending such a conversation about word definitions, attempting to be substituted for a conversation of technological progress, has any real meaning. Such a simple term as “crosswind power” sounds pretty self-explanatory to me, but to each their own.
I agree with @dougselsam on this one. The blades of the Kiwee are moving fast in a direction mostly perpendicular to the wind. It doesnt matter much that the lifter is stationary. It is just infrastructure
Let’s call the phenomenon ‘crosswind window’ power. In the case of Deep Green and Makani we obtain almost 10 times the effective wind/tide velocity with an enormous increase in power. This is the phenomenon we should try to capitalize on.
When I think of window power, it reminds me of a joke:
Did you hear about the guy with the car door in his living room?
Question: “Why do you have a car door in your living room”?
Answer: “So when it gets hot I can just roll the window down!”
Makani started out as “just the tips”.
At last count their (just-a-tip) “tip” had 50 tips(?)
2 wing tips
8 pylon-nacelle “tips”
40 blade tips
50 tips total
Every tip involves what is known as “tip losses”, the biggest source of energy loss (induced drag) for aircraft, wind turbines, etc.
No wonder it struggles on its upward trajectory.
But good it is being tried at least - it would be sad to think nobody gave it a good try, which is the case with so many other nascent AWE possibilities.
One underappreciated aspect of rotors spinning in such artificially high windspeeds is to keep a 6:1 TSR your blade tips approach supersonic speeds. So, predictably, they must sacrifice rotor performance by raising rotor solidity (5 wide blades), lowering TSR, which weighs more, and costs more, while reducing efficiency.
Band-aid after band-aid, most wannabe wind energy breakthroughs end up shooting themselves in the foot, one way or another.
Deep Green? My prediction is they will get so “deep” into debt (“green”) that they will eventually evaporate - even underwater!.
Funny thing is, most water energy turbines break their blades and fall by the wayside, ending up in the “abandoned news” cycle. (quietly go away)
Right - I’m back to claiming Daisy has the most crosswind AWES blades. The speed difference between the root and tip is much less than that of a turbine with a root fixed to the axis. Therefore the average surface of blade is moving at a higher speed ratio compared with rooted turbine. Also, the blade is sweeping across more wind frontal area then a fixed root turbine. So the plane of rotation isn’t flat to wind like kiwee but it sweeps across way more wind per blade area.
From my analysis I am unable to find any real dealbreakers with Makani’s concept. Travelling at ~50 m/s, a TSR of 6 should give them an approximate speed of 300 m/s, just under the speed of sound. It sounds like a few adjustments will place them a bit lower without too ill consequences. (ie less TSR or slower flying speed)
I also gather mass is of less importance to Makani, with just practical/sensible limits. I gather they are in good shape, perhaps apart from the complexity/safety issues with is similar across AWE, somewhat different only based on chosen platform.
In the battle between drag (Makani) and lift mode AWE (Kitemill/Ampyx etc) the most important question right now seems to be which has more utility: controlling the winch or being able to adjust drag dynamically…
In the contest for the most crosswind system I recon the good old windmill is probably the winner, as most AWE will probably want some elevation angle in order to catch better wind and not hit the ground… however you solve that, elevation angle will cause a «cosine loss»…
I reckon there is no Crosswind AWES
@dougselsam is right @Kitewinder Kiwee-one is the most crosswind AWES.
The rotor is fixed so that the motion is 100% perpendicular to in-coming wind
Linear rail sweeping AWES were tested… but they didn’t sweep continually so a lot of their time is stalled.
Skysails crossing an ocean will always deviate from the 90deg to the wind.
There are side to side pumping network kites proposed, similarly the path of those kites would stall at the ends and also be slightly bowed to the middle.
SuperTurbine(R in a circle symbol registered trade mark ) is very crosswind - it holds tight to it’s axis thus the blades don’t sweep around out of the wind window - but its axis is slanted at an elevation angle.
The blades move 100% crosswind, but the wind turbine does not move integrally because it is fixed, while the crosswind AWES move integrally, and more or less crosswind due to the elevation angle.
Now, to be concrete, which AWES do you favor? A rotary device which is stationary while the blades travel in a circular path, 100% crosswind (like Kiwee), or more or less crosswind (like tilted rotary AWES)?
You could just as easily point out that most any AWE system doesn’t really move, but has an overall fixed location determined by the ground station. In both cases, the working surfaces move crosswind. For tilted rotors, power is of course affected by the tilt angle. The silly thing is, even mentioning the term “crosswind”, but, as usual, the fantasy-world of AWE gets the basic terminology wrong. It all gets so silly after a while, one wonders what is the point of dissecting the words used to this extent? Seems like the noncomprehension of established terminology merely serves as one more indicator of general lack of knowledge of basic wind energy concepts. As the old saying goes, “a rose is still a rose by any name”, similarly, if you have a practical wind energy system, it doesn’t make much difference what words are applied to it, so much as how much energy it collects, how reliably, at what cost.
meh… yoyo is most crosswind. In the eeturn phase you gain altitude thus generating power from the wing actually going UPWIND. You cant beat that
The tether is deemed to replace the tower.
And for the current prototypes the tether goes crosswind with the kite, unlike the fixed tower.
In this case, indeed yo-yo is quite crosswind.
So currently flexible crosswind kites in yo-yo mode seem to emerge. For massive marketing it is another affair.
Keywords: “appears to be”.
I was once very swayed by such claims of high output by kite-reeling systems. But then I noticed that no matter how much power they claimed to make, we never saw one in regular operation. Now, close to a decade later, we’re supposed to be swayed by reports of a couple systems being “sold”, “shipped to Asia”, etc.
I am at the point where I do not necessarily believe any more of this nonsense. To me, any such statement of “success”, whether it is “we will be powering X hundred homes in remote location Y by date Z”, “we have a factory”, “we’re renting office space!”, or “we’re shipping a unit(s)” are all suspect, all unlikely to be followed up on, and really, all pretty-much meaningless. For example the statement a year ago of shipping a system alternately to “Mauritius” or “Asia” - I was pretty sure that was the end of that story, and we’d never hear anything more about it. A year later now, that seems to be true.
Still no reports of anything in regular operation.
I think the “fake it til you make it” paradigm is in full effect, but the question is, will the “make it” part ever emerge. “Fake it” seems to be all that’s going on so far. The whole time, it;s been easy to see, if any of these big-talker teams had anything really working, as in continuous operation, regularly providing power for anyone, we’d have heard about it.
How about “the tether replaces the blade root, supporting the blade tip”?
Like this?
