Big Claims for Little Turbine

June 5, 2014

I like this video because its a look at new technology, and a great music break as well.  Historically, small turbine technology has had a tough go – but with continued efforts like this, who knows?

Gizmag:

Although it’s getting increasingly common to see solar panels on the roofs of homes, household wind turbines are still a fairly rare sight. If Rotterdam-based tech firm The Archimedes has its way, however, that will soon change. Today the company officially introduced its Liam F1 Urban Wind Turbine, which is said to have an energy yield that is “80 percent of the maximum that is theoretically feasible.” That’s quite the assertion, given that most conventional wind turbines average around 25 to 50 percent.

The 75-kg (165-lb) 1.5-meter (5-ft)-wide Liam obviously doesn’t look much like a typical turbine. It draws on the form of the nautilus shell, and the screw pump invented by ancient Greek mathematician Archimedes of Syracuse.

That form factor reportedly results in minimal mechanical resistance, allowing it to spin very freely and to operate quietly – blade noise is one of the common complaints regarding rooftop wind turbines. Additionally, the design is claimed to keep it always pointing into the wind for maximum yield.

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17 Responses to “Big Claims for Little Turbine”

  1. shaneburgel Says:

    Where can I but this?

  2. johnrussell40 Says:

    I suspect that the ’80% efficiency’ claim means 80% of the available energy is collected after the variation in windspeed is accounted for. In other words that claim is not comparable with the wind load factor (WLF) given for most large turbines (typically in the UK, onshore, around 30%) and which is dependant on the average wind speed prevailing at the location where the turbine is erected, and its tower height.

    The main problem of small domestic turbines is the lateral load they generate which, when retro-fitted to the roofs of buildings, creates point loads, and consequently the need for additional strengthening of structures. The alternative solution is independent towers with strong foundations. But both these requirements can be as expensive as the turbine itself. This is why micro-turbines will never be as popular as PV, which, with no moving parts and because it spreads its load across a roof, is a fairly cost-effective retrofit.

    • joffan7 Says:

      I think the 80% efficiency claim – even if accurate – is problematic, because the efficiency relates to the area swept. In the case of this design the turbine occupies just about the whole of that area. A blade design that had blades say 3 times the length of the radius of the Liam turbine might be only 30% efficient but sweeps an area that is 9 times bigger. So 0.8 (80%) compares then to 0.3×9 = 2.7, and the energy drawn with the “inefficient” turbine is more than 3 times greater.


      • Not only that, it’s got a huge amount of surface area for its frontal area (which isn’t all that large either) and it can’t be feathered.  In short, the first ice storm is going to collapse it, and a major wind storm will tear it off the roof.

        You will see this thing go quietly where all the other clever-looking things have gone before it, never to be seen again except perhaps as children’s toys or art mobiles.


  3. It’s a horizontal Savonius. The amount of material is greater than the three bladed up wind. Betz limit places the theoretical maximum extracted energy at 59.3%, based on the change in momentum in the airstream. 80% claims are dubious. We will see if we get the published power vs velocity curves. I don’t think manufacture is cheaper.


  4. […] I like this video because its a look at new technology, and a great music break as well. Historically, small turbine technology has had a tough go – but with continued efforts like this, who knows…  […]


  5. […] I like this video because its a look at new technology, and a great music break as well. Historically, small turbine technology has had a tough go – but with continued efforts like this, who knows…  […]

  6. rayduray Says:

    It seems that we have some thoughtful engineers among us. I’m wondering about combining this Archimedes screw with proposed commercial level exploitation of the Gulf Stream’s energy off the coast of Florida? I like the Archimedes design because with proper turtle excluders installed, it sure seems a lot better solution for wildlife interactions than the rather aggressive three-blade model the Florida Atlantic Univ. folks are experimenting with now.

    http://www.pennenergy.com/articles/pennenergy/2014/06/fau-signs-lease-to-install-world-s-first-ocean-wave-energy-test-site.html

    http://snmrec.fau.edu/

  7. MorinMoss Says:

    Even if the claims hold, these turbines would probably never be very large – would probably never reach megawatt output from a single turbine.

    And what about it being covered in ice? There’s a lot of surface area that would get coated.

    • Phillip Shaw Says:

      Morin, you bring up a very good point about ice – freezing rain would rapidly coat the large surface area. That’s just one of several puzzling aspects of the design.

      I looked at the website for the wind turbine and its rated power is 1 kw. That’s not much, about four PV modules worth, and the output drops to 510 W at a wind speed of 10 m/s (22 mph). A 22 mph wind is pretty breezy for most urban areas. As I write this Chicago, the “Windy City” has 2 mph winds and, according to wunderground.com, isn’t forcast to have any winds above 20 mph in the next ten days. Here in Austin it’s even calmer with nothing over 15 mph in the next ten days.

      Urban winds are notoriously variable in both direction and amplitude. This turbine would be constantly yawing and the output would fluctuate wildly. I just don’t this design as competitive.

      Anyone interested in wind turbines for urban settings should study the available vertical axis wind turbines. Their big advantage is that they are omni-directional and thus unaffected by shifts in wind direction. As one example of many on the market, the Aeolus-V 1000w has a diamter of 2 m, and an output of 1 kw at a wind speed of 22 mph, twice the output of ht Archimedes.


    • Let’s not forget there are many parts of the world that never see snow and have need for small local scale electric generation. Not every technology is designed to replace a nuclear power plant.


  8. If urban developers were serious about wind power, they’d revive the electrostatic wind generator.  No moving parts, and they could be strung between skyscrapers to get some serious area coverage.  I first saw the concept about 30 years ago, but here’s a recent treatment:

    http://www.trendhunter.com/trends/electrostatic-wind-energy-converter

    Only one active electrode is required; the earth is the return path for the charge from falling water droplets.


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