Could a new generation of wind turbines on residential rooftops be on the way? Saying no might be easy when imagining blade noise, if nothing else. The idea of wind turbines for generating energy in households may draw several arguments against the idea. One may argue the yield from current-generation turbines would be too low, along with having to put up with the noisy blades. A group based in Rotterdam which describes itself as an "R&D" company "built on the re-invented formulas, drawings and principles of Archimedes" is out to change minds. On Tuesday, the company, also called The Archimedes, unveiled its Liam F1 Urban Wind Turbine. The Liam, according to the company, ushers in a "totally new generation of wind turbines for domestic use."

The company said that the turbine easily fits on the roof of a house just as would solar panels. The Liam F1 generates an average of 1,500 kilowatt-hour of energy at a wind-speed of 5m/s, which resembles half of the power consumption of a common household. In combination with solar-panels on the roof, a household could be totally self-supporting for its own energy needs. The Archimedes CEO Richard Ruijtenbeek said, "when there is wind you use the energy produced by the wind turbine; when the sun is shining you use the solar cells to produce the energy."

Because of its design, the Liam addresses limitations of efficiency and noise. The inventor, Marinus Mieremet, company CTO, created a type of turbine that is virtually soundless. The Liam is based on "the laws of nature and the theoretics of the Greek mathematician Archimedes." The form of the Liam is a Nautilus shell. The Liam automatically like a pennant goes for the optimal position of the wind, pointing into the wind for maximum yield. According to Mieremet the yield is 80 percent of the maximum that is theoretically feasible.

Explaining the design, according to the company, "Most today's wind turbines require that a difference in pressure between the front and the rear side of the rotor blades be maintained in order to be effective. However, this difference in pressure also has a negative effect called 'drag'. Our turbine rotor captures the kinetic energy of the wind due to its speed, and, by reversing the wind and reducing it to almost zero Beaufort converts it into mechanical energy. By doing this the wind speed's effect (in kinetic energy) on the rotor is maximized and 'lift' is obtained by the wind's acceleration over the rotor plane."

The Archimedes started in 2006, founded by Mieremet and Ruijtenbeek. The announcement on Tuesday also noted that the company has started developing relatively small turbines for use on boats, on lampposts and in water.

## User comments

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## Perception

## vlaaing peerd

I've seen a demonstration, though I live in a predominantly windy (and rainy ⌐⌐ ) country, I'm doubting the 5Kw/h output...it's quite a lot for such a small device.

## Perception

I guess I do have skin-in-the-game as you put it as I've got designs on paper for urban wind power generation of my own and I see the potential of this product. The UK doesn't get much sun as you know but yes I think we could put the wind to work.

## Whydening Gyre

## SiBorg

Agreed, it does seem like a typo on the energy figure.

1.5kWhr at 5m/s seems more plausible than 1.5MWhr.

For comparison the Bonus 1.3MW Combistall machine (http://www.wind-e...3-mw62/) needs a 62m blade diameter to produce that amount of power and won't start doing it till the wind hits 15m/s.

## bikengr

When my students and I looked at providing more than half of a home's needs with an average windspeed of 3 m/s, we needed a rotor diameter of 27 ft. If these innovators want to provide the energy for a home, they need a size approaching that, because of the general principle that the power/area of a given wind speed must be captured by a large enough area.

## Eikka

In what? A week, a month, a year?

Wind follows roughly a Rayleigh distribution when free of obstructions, so the average windspeed on a given day or similiar short interval, when the long term average is 5 m/s, is 50% likely to be less than about 4.3 m/s.

Wind speeds of less than 4.3 m/s represent on average 3% of the total available power from 0 to 12 m/s where the windmills typically furl out to protect themselves, so on your typical day, you have about half the chance of getting "nothing", and the probability of getting a whole week of these lulls is about 1/128 which means it should happen about three times a year.

So better stock up on batteries.

## Eikka

However, the probability of going 5 days in a row without appreciable power from the windmill is 1:32 or 2.28 times a year.

Of course this is no problem if you intend to outsource your power balancing to the nearest coal burning facility.

## tadchem

## TheGhostofOtto1923

## ormondotvos

## Benbenben

"...The Liam F1 generates an average of 1,500 kilowatt-hour of energy at a wind-speed of 5m/s, which resembles half of the power consumption of a common household..."

...is meaningless since it does not give any reference to the time at that windspeed required to generate 1500 kwhr.

## Straw_Cat

These look quite suitable to include in a solar-optimal Net-Zero Energy or Passive House of the kind I would like to build next. I should be able to get it- the house- to run off less than 2 kws. (I've seen some that run off a 300 watt solar panel...

The spiral turbine will likely be less of a disturbance to the goats and chickens up on the living roof.... :-)

## Saltpeter

## RealScience

Energy: Energy is power times time, so clearly either the 1500 kWh should be kW, or a time period is missing. Let's figure out which:

From the spec sheets in a 5 m/s wind it should produce ~125W, which is four orders of magnitude less than 1500 kW (and 12x less even than 1500 W), so it looks like a time period is missing.

At 5 m/s it would take 1.5 kWh/.125 kW = 12,000 hours to generate 1.5 kWh, or a bit over a year.

However at an AVERAGE wind speed of 5 m/s the energy would be a bit higher because the gain in higher wind exceeds the reduction in lower wind. The yearly total should be a bit higher than 24 Hours/day * 365 days/year * 0.125 kW = 1095 kWh/year.

So the average of 1500 kWh at 5 m/s wind is probably a corruption of 1500 kWh PER YEAR in a location where the wind AVERAGES 5 m/s.

## roldor

http://sun-innovation.de/

http://www.turbin...-turbine

## bikengr

Thanks for finding the spec sheet. A rule of thumb estimate is that power is proportional to the cube of wind speed. So given the 10 m/s power, in a 5 m/s wind power should be 508/(2^3) = 64 W

This is not going to put much dent in a household's power budget. (And the situation is even bleaker if wind speed is 3.33 m/s, expect about 20 W.)

Now look at the problem financially: a yearly energy budget of 4000 kWh costs about $800. If you make about 1/8 of your needs with a wind turbine, you are saving $100 per year. If the turbine costs any more than $1000 to purchase and mount, it will probably wear out before it pays itself back.

My students designed a 30-ft diameter turbine to sell for $3000 and pay itself back in about 5 years, when average wind speed is 3 m/s. But to survive high wind speeds it has to auto-furl.

## ivo_dekeijzer

http://www.telegr...s__.html

## Newbeak

## RealScience

Thank you for catching my careless mistake!

## Urgelt

Previous commenters have nailed it. It's a wee little energy harvest, no doubt with a payback period that will make even rubes choke. Add in the cost of electrical equipment required to integrate it into household current and it's a total nonstarter.

But of course advertising can sell anything. Anything at all, particularly if news media asks no hard questions.

## antialias_physorg

## Macrocompassion

## egutzait

Source:http://dearchimed...ttyPhoto

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