Fish schooling as a basis for VAWT farm design (preprint). "...over one order of magnitude..."

[joshcryer]

"...for a given area of land as compared to HAWTs."

These results are astonishing, and while it is still early yet, I think VAWT has a bright future (and this guy may have just got himself rich by patenting the design).

Most wind farms consist of horizontal axis wind turbines (HAWTs) due to the high power coefficient (mechanical power output divided by the power of the free-stream air through the turbine cross-sectional area) of an isolated turbine. However when in close proximity to neighbouring turbines, HAWTs suffer from a reduced power coefficient. In contrast, previous research on vertical axis wind turbines (VAWTs) suggests that closely-spaced VAWTs may experience only small decreases (or even increases) in an individual turbine’s power coefficient when placed in close proximity to neighbours, thus yielding much higher power outputs for a given area of land. A potential flow model of inter-VAWT interactions is developed to investigate the effect of changes in VAWT spatial arrangement on the array performance coefficient, which compares the expected average power coefficient of turbines in an array to a spatially-isolated turbine. A geometric arrangement based on the configuration of shed vortices in the wake of schooling fish is shown to significantly increase the array performance coefficient based upon an array of 16×16 wind turbines. Results suggest increases in power output of over one order of magnitude for a given area of land as compared to HAWTs.

Link to paper here: http://arxiv.org/abs/1002.2250

[joshcryer]

1. Bump

This deserves another kick to the top imo. It disproves the vitriolic HAWT claims we were seeing a few weeks back.

[kristopher]

2. It disproves nothing.

It deals with one consideration among the many that must be tallied to determine the optimum technology for a given application. It tells us nothing that wasn't known before except that it posits an optimum spacing that delivers somewhat more power by taking advantage of localized turbulence from adjacent turbines.

What it doesn't address is much more significant than that lone factor. VAWTs simply don't scale up with the same economic efficiencies that benefit HAWTs. There may be some limited applications where the VAWT is a better choice, but outside of your fantasies, the HAWT is nearly always the way to get the most electricity for the least money.

[joshcryer]

3. Why don't VAWTs scale up?

A magnitude more power from the same area is certainly notable.

[kristopher]

4. For the same reasons they didn't scale up a few weeks back...

You wrote, "It disproves the vitriolic HAWT claims we were seeing a few weeks back."

Those "vitriolic HAWT claims" were that increasing both the swept area of the rotors and the altitude where the wind is gathered are much more economically accomplished with HAWTs than with VAWT.

The real question is why do you insist on ignoring the obvious shortcomings of the technology?

[joshcryer]

5. You didn't answer my question, why is it "more economically accomplished"?

I have said that VAWTs cannot, individually, be more efficient than HAWTs. However, we know have strong evidence that for installed area, VAWTs destroy HAWTs. So dismissals of VAWT are clearly misplaced ignorance.

Now if you want to discuss the economic implications, feel free. I know that economies of scale makes it so that mass produced VAWTs can be competitive with HAWTs, and it is clear that the California Institute of Technology thinks it has potential, and is investigating it further.

Note, it appears to me that you might be reading in to what I am saying and deluding yourself that I am saying VAWTs will replace HAWTs or are better than HAWTs in all situations. Absurdity, if that is really what you think.

You dismissed the Fish Schooling implications outright, and you know it. It's way beyond anything I imagined it would be.

[kristopher]

6. We already had this idiotic discussion, why do you ignore what was presented there?

Is it short term memory loss from too much reefer?

[joshcryer]

7. I'm glad that VAWTs show a magnitude more energy production per unit of area.

[kristopher]

8. formula to calculate the energy content in wind: Power =1/2p A V^3

Where p is the air density (just like any other density -- how much a given volume of wind weighs), A is the swept area of the blades (how much surface area of the turbine actually catches wind) and V is the velocity of wind usually measured in mph. Notice that the velocity of wind is raised to the power of 3.

This tell you that the most critical factors are:
velocity of the wind (tall towers are essential) and
swept area of the rotors (HAWTs have swept areas significantly larger than a football field)

You can't design a VAWT that is comparable in height and swept area for a price that even begins to come close to a HAWT.

A marginal increase in the power yield in the low altitude/low wind/small VAWT turbine does nothing to address the much more significant variables described.

This is a perfect example of how you allow personal preferences to color your ability to internalize information that contradicts those preferences. It is the antithesis of "science" based analysis.

[joshcryer]

9. I'm glad that VAWTs show a magnitude more energy production per unit of area.

[joshcryer]

11. "You can't design a VAWT that is comparable..."

"...in height and swept area for a price that even begins to come close to a HAWT."

By what technological limitation do you make this statement? Hint, it's made up bullshit. It's like someone claiming 10GW HAWT isn't possible.

The vertical placement of the shaft reduces complexity considerably.

[kristopher]

12. Then please describe a VAWT with 60,000 ft^2 swpt area with center point at 300 ft high

How precisely do you envision that working?

What is the reason this design advantage you claim has been ignored by the thousands of highly qualified engineers working in the competitive environment governing today's wind turbine market?

[joshcryer]

10. VAWTs show a magnitude more energy production per unit of area.

[kristopher]

13. 1.2 - 3 meter wind turbines are the junk market.

You claim to want to do something about climate change yet you spend your time promoting the most useless type of wind energy out there. Turbines of this size are a useless scam designed to suck money from gullible people who have a desire to do something worthwhile. The electricity produced by ANY turbine in this range of size is some of the most expensive and unreliable out there.

The modern turbines being used to actually do something about climate change have a rotor size 110 - 150 meters and produce some of the LEAST expensive electricity available from a newly built generating source.