Bold new approach to wind 'farm' design may provide efficiency gains

[OKIsItJustMe]

http://www.eurekalert.org/pub_releases/2011-07/aiop-bna071311.php

Public release date: 13-Jul-2011

Contact: Charles E. Blue
[e-mail]
301-209-3091
http://www.aip.org/">American Institute of Physics

Bold new approach to wind 'farm' design may provide efficiency gains

College Park, Md. (July 13, 2011) -- Conventional wisdom suggests that because we're approaching the theoretical limit on individual wind turbine efficiency, wind energy is now a mature technology. But California Institute of Technology researchers revisited some of the fundamental assumptions that guided the wind industry for the past 30 years, and now believe that a new approach to wind farm design—one that places wind turbines close together instead of far apart—may provide significant efficiency gains.

This challenges the school of thought that the only remaining advances to come are in developing larger turbines, putting them offshore, and lobbying for government policies favorable to the further penetration of wind power in energy markets.

"What has been overlooked to date is that, not withstanding the tremendous advances in wind turbine technology, wind 'farms' are still rather inefficient when taken as a whole," explains John Dabiri, professor of Engineering and Applied Science, and director of the Center for Bioinspired Engineering at Caltech. "Because conventional, propeller-style wind turbines must be spaced far apart to avoid interfering with one another aerodynamically, much of the wind energy that enters a wind farm is never tapped. In effect, modern wind farms are the equivalent of 'sloppy eaters.' To compensate, they're built taller and larger to access better winds."

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The Caltech design targets that power by relying on vertical-axis wind turbines (VAWTs) in arrangements that place the turbines much closer together than is possible with horizontal-axis propeller-style turbines.

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http://www.youtube.com/watch?v=kz6dw_BIdNA

[PoliticAverse]

1. Great video. n/t

[Scuba]

2. I'm still waiting for the Horizontally Aligned Wind Turbine (HAWT) to install on my roofline....

...all the wind here should be good for something besides drying out the garden.

[OKIsItJustMe]

7. Like this?

http://challenge.ecomagination.com/home/SmartWind-RidgeBlaster-18-kW-wind-turbin
http://www.youtube.com/watch?v=7PR0Tng_zYQ

[Scuba]

13. This is exactly what I was looking for....

...sounds like I'm ahead of the curve, plus I already built my retirement home, but this looks just like what I was thinking.



Thanks for posting.

[DeSwiss]

3. Interesting.

I posted a video on this vertical wind turbine design back in http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=385x567851">March

Then there's also these ideas to consider:

http://www.businessweek.com/globalbiz/content/dec2009/gb2009127_163138.htm">Hydropower Without Dams

http://link.brightcove.com/services/link/bcpid1214137061/bctid1233395616">Windbelt Micro-wind, 10 Times Cheaper Wind Energy!!

K&R

[kristopher]

4. Watts per meter^2 isn't a critical issue, $$/watt is

The design requires VAWTs.

VAWTs are not able to be raised to high altitudes, they operate close to the ground.

To see the consequences of that limitation go to this link and open the first and last files. The first is energy density of wind at 100M (HAWT operational altitude) and the second is the energy density of wind at 30M (VAWT operational altitude.

http://blog.climateandenergy.org/2008/09/29/new-kansas-wind-maps-posted-100m-70m-50m-30m/

The second limitation of VAWTs is that their swept area is very difficult to enlarge by making blades larger. To increase the area of space you are sweeping for energy you must build more towers and generators and blades.

HAWTs just enlarge everything at a much, much smaller marginal cost.

The research has limited use.

Previously discussed here:
http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=115x300573

[OKIsItJustMe]

5. Watts per square meter certainly is an important limiting factor

We have a finite number of square meters.

That’s one of the reasons for looking at (more expensive) off-shore wind sites (getting more square meters.)

[FBaggins]

6. Correcy.

And the number of square meters impacts the $/watt since land isn't free.

I'm not sure that "bold" belongs in the title... but the rest is good news.

[txlibdem]

9. 10x to 15x increase in watts per square meter of land - that's pretty significant

Tests showed that an arrangement in which all of the turbines in an array were spaced four turbine diameters apart -- about 16 feet -- completely eliminated the aerodynamic interference between neighboring turbines.

By comparison, propeller-style wind turbines would require spacing them about 20 diameters apart, a distance of more than a mile between the largest wind turbines now in use.

The vertical turbines at the Caltech experimental farm generate 21 to 47 watts of power per square meter of land area, whereas a comparably sized horizontal turbine farm generates just 2 to 3 watts per square meter, the researchers said.

http://www.winddaily.com/reports/New_wind_turbines_said_more_efficient_999.html

This is interesting research that needs more study to verify the findings (as is proper scientific method) but if those numbers hold up... wow, things are going to change in the wind industry and home wind power.

[kristopher]

10. No, it doesn't need more research to verify its findings, but more research is required.

And you read it above with the post that links to the wind maps.

The research is acceptable to answer the question the research asked; "can spacing and arrangement of VAWT's be enhanced?"

The answer is yes, and it is quantified properly and sufficiently to allow us to fit the data into the larger body of knowledge; which includes "what are the other ways of enhancing productivity of a given volume of air?" and "how does this compare to those alternatives."

The paper does a comparison to "a comparably sized horizontal turbine farm " but it does not address methods used to enhance productivity with the horizontal turbine farm. Once that method is identified and the CalTech research is placed in a context comparing it to the cost and productivity of the standard method used to enhance the productivity of the HAWT we see that increased size is a better approach than increased numbers of foundations.

[txlibdem]

11. You really don't know about the scientific method??? You must be joking?

Any scientific paper has to be independently verified. That's how science works. Only when other teams of scientists can follow the procedures that the first group of scientists documented --and reach the same conclusions-- then and only then is it accepted by the scientific community.

The one major thing they *do not* do is to state their conclusions until the proper scientific process has been completed. Never. Ever.

[Name removed]

12. Deleted message

Message removed by moderator. Click here to review the message board rules.

[kristopher]

8. You do love nitpicking semantic games, don't you?

The comments I make are specific to the content of the study which compares meter^2 of horizontal surface area, which is an irrelevant metric by which to judge the best solution to the problem of maximizing production in any given volume of air above that surface.