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Windmill tests

Home Forums Archive Infrastructure Windmill tests

This topic contains 11 replies, has 7 voices, and was last updated by Avatar of i_is_j_smith i_is_j_smith 4 years, 10 months ago.

Viewing 12 posts - 1 through 12 (of 12 total)
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  • #888
    Avatar of bencoder
    bencoder
    Participant

    A real-world test performed by the Dutch province of Zeeland. Twelve small wind generators were placed in a row on an open plain. Their energy yield was measured over a period of one year, the average wind velocity during these 12 months was 3.8 meters per second. Three windmills broke.

    Original Article(Dutch): http://provincie.zeeland.nl/milieu_natuur/windenergie/kleine_windturbines/de_turbines

    English Summary: http://www.lowtechmagazine.com/2009/04/small-windmills-test-results.html

    Interesting tests, judging by that, it looks to me like the skystream takes the win, although it comes second in raw output, it is almost half the price of the top generator and has smaller blades, and the difference in power generation isn’t really very big. With the bigger wind speeds available out to sea, I would expect one of those could power a homestead quite comfortably.

    #5764
    Avatar of kbxx
    kbxx
    Participant

    What about verticle axis windmills? I’ve seen a model that costs $400 and can conservatively kick out 40 kwh in a months time. Thats not a whole lot, but the big windmills might be too big for early seastead applications.

    I figure the 40 kwh figure may actually be low because it can get quite windy out on the open sea. And 40 kwh is about the monthly energy usage for lighting a 3500 sq. foot house in a month. Use high efficiency LED or CFL lighting and thats even better.

    #5769
    Avatar of Thorizan
    Thorizan
    Participant

    The cost of steel to make a big tower and slap a big turbine on top may be cost prohibitive versus a few vertical windmills and a smattering of batteries, especially if you are talking about single family seasteads. Larger units, where modularity is not the desire, will probably do better with larger turbines.

    __________________________________________________
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    #5772
    Avatar of i_is_j_smith
    i_is_j_smith
    Participant

    At least according to this test, the design of the windmill doesn’t matter at all…it’s the diameter of the rotor that matters.

    Now I guess it’s possible that you can fit a larger diameter rotor from a vertical axis windmill into areas where a large diameter horizontal axis windmill wouldn’t fit, but I don’t think so.

    I guess it’s like the ladies always say…bigger IS better.

    #5773
    Avatar of i_is_j_smith
    i_is_j_smith
    Participant

    Even a single family seastead is going to need 6-8 of the larger 4-5m diameter windmills to be self-sufficient. The study says you would need 6 of the Montana or Skystream windmills to power a typical American house…and most American households aren’t running desalinization, hydroponic, or fish hatchery facilities let alone station keeping-engines.

    The study recommends that you always look for a single, larger windmill to meet your needs, rather than relying on multiple, smaller windmills.

    #5778
    Avatar of kbxx
    kbxx
    Participant

    I wonder, would it be more practical to run a smaller seastead on gas generator? Its far more expensive than grid electricity, but wind solar and wave have huge upfront costs. There really doesn’t seem to be a good solution to powering seasteads. Its definitely the biggest technical problem. Early seasteaders are going to have to find whatever solution is “less bad”.

    #5780
    Avatar of Thorizan
    Thorizan
    Participant

    Seasteads themselves have a huge upfront cost… far more than that of a series of horizontal, or one or two big vertical, windmills. With more constant, and stronger, winds on the oceans, fewer windmills would be needed to power a structure. Several vertical turbines on the windward side of a structure should be sufficient to power a modest seastead. Larger structures would do well with, not oddly, larger windmills.

    Finding viable power supplies will not be the biggest issue that plagues the creation of seasteads, however. Design and funding will be greater hurdles to overcome, in my estimation.

    __________________________________________________
    There is no fate but what we make for ourselves. Each to his fate.

    #5821
    Avatar of thebastidge
    thebastidge
    Participant

    “The study recommends that you always look for a single, larger windmill to meet your needs, rather than relying on multiple, smaller windmills.”

    The study is not taking other factors into account, only price and total generation capacity. Most studies with an urban focus in mind will not be worried about redundancy, for example. Mounting of the windmill is only mentioned in passing, towards the end as well.

    Clearly, issues of scaling are a major factor in design considerations. The study seems dismissive of design consideration other than size- while size would pretty clearly be a major factor, I can’t believe that design is that unimportant. It seems the study starts out to debunk the idea of small urban windmills. While it may be important from a policy standpoint to do so, that doesn’t mean it’s great science.

    #6003
    Avatar of jcrawford
    jcrawford
    Participant

    I think the vertical windmills are definitely looking in to. They’d be much simpler to work with. I think I remember reading that several kinds of vertical-axis windmills can operate at lower windspeeds than horizontal systems, as well.

    #6010
    Avatar of Carl-Pålsson
    Carl-Pålsson
    Participant

    Vertical axis wind turbines seem to be very rare out in the real world. At least here in Europe. There are probably good reasons for this. For one thing, the airfoils on a VAWT are subject to changing angles of attack from the wind during the course of rotation. Apparently this can produce pulsating forces that probably take their toll on the structure over time and perhaps makes them noisier.

    http://en.wikipedia.org/wiki/Vertical_axis_wind_turbine

    And, as always with wind power, the turbine is just a part of the system. Sometimes there is no wind, so you need to budget an energy storage system as well.

    #6169
    Avatar of Thorizan
    Thorizan
    Participant

    Yay for spam!

    __________________________________________________
    There is no fate but what we make for ourselves. Each to his fate.

    #6219
    Avatar of i_is_j_smith
    i_is_j_smith
    Participant

    Here’s an article from CNET, about how 100kW and under wind turbines are selling like hotcakes:

    news.cnet.com/8301-11128_3-10251112-54.html

    They do say that these small turbines underperform, and link to two studies that show this.

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