What a surprise...

[The Medway Handyman]

B&Q takes wind turbines off shelves Turbine range withdrawn from sale after recent survey reveals they don't work as effectively as first thought

[Alan]

In message , The Medway Handyman wrote

that B&Q first started stocking the wind turbines. Studies had already been published that concluded that in the majority of urban environments that the energy produced to the £1k investment would be negligible.

[Jules]

Bet they're still selling CFLs though ;)

[Frank Erskine]

grounds of unfitness for purpose. Or perhaps misleading advertising.

[Rod]

There were some purchasers?

[Andrew Gabriel]

It sort of implies they will, and says they're even proactively contacting the purchasers of them to let them know.

I wonder if they're getting the money back from their suppliers?

[Arthur2]

This subject has been on my mind for the past 2 days. All wind turbines seem to be blades mounted vertically on a horizontal axle/axis. These can only be 100% efficient if the wind blows directly onto the face of the blades.

If instead of blades they had the things you see on some wid speed measurement devices that have 3 or more cup shaped receptacles on horizontal bars fixed to a vertical axis. The wind can hit these assemblies at any angle it chooses with no difference to the efficiency of the 'machine'.

I can only conclude that the prevalance of bladed wind turbines means there is a basic weakness of the wind-vane method.eg transmission of energy or torque or something like that.

Anyone got any ideas on this?

Arthur

[damduck-egg]

Coincidently this design was in the news today at a town not far from me.

the store mentioned has installed them at a number of locations.

One phone in caller made a point that possibly a better way to save energy would be to shut the store an hour earlier .

G.Harman

[<me9]

Didn't a Mr Cameron get one?

[Arthur2]

{Writes word 'geoff' on piece of paper and discovers has inadvertantly carved it into laminated desk surface}

Arthur

[geoff]

In message , Frank Erskine writes

I'm waiting for them to ban dolphin showers as being unfit for porpoise

[John Rumm]

That is why these things have a big tail fin and a turbine body that is free to rotate - they should always face the wind if there is a nice steady flow. Needless to say in an urban environment with turbulent flow they can't ever really face the wind since it gusts from all over the place.

Anemometer?

That is what the tail does really...

[Jules]

I suspect it's a bit harder to 'feather' those sorts of designs so they don't self-destruct during really high winds. Other than that though, not sure...

Related note: aren't the "egg beater" vertical turbines supposed to be more efficient than horizontal-axis ones, and will also (like the anemometer) work happily with wind blowing from any direction?

[Andy Dingley]

That's why they can be trimmed into the wind

Or indeed out of it, as one way to survive over-strong winds.

Vertical axis machines have much lower efficiencies in comparision. They're getting better, and in gusty, crowded urban settings they might even have the advantage.

[Arthur2]

Also I think the bladed turbines are more difficult to design mechanically and maintain. If the Anemometer had several sets of 'cups' of differing sizes with I dunno...a sophisticated gearing system that demesh cup sets if the wind is too strong and optimise for starting up after a wind drop.

Arthur

[The Medway Handyman]

Now that is a good point. But this is about greenwash, not saving enegy.

[matthew.larkin]

Isn't part of the problem that the "cups" have to be driven in reverse through the air-flow though? So when facing the wind, the cup catches the air and is driven backwards, but the cup on the exact reverse of the pole is actually having to go forwards through the wind?

Matt

[Arthur 51]

If the cup was a cone or bugle shape the resistance would be reduced significantly I would assume.

Arthur

[dennis]

And it has to do so faster than the one going with the wind. Not ideal for generating power rather than counting revs.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember geoff saying something like:

Is this your coat? The one with 'Tarbuck' embroidered on the breast pocket?