Wind turbines and other eco generating issues...

[Nemesis]

Been thinking hard about a small one... although it may be that there are planning and siting problems (not to mention cash...) but thinking anyhow...

...until Sunday, when we went for a walk to Talkin Tarn Brampton, where a small wind turbine has been sited near a former boathouse which I think is now a hide. Not sure what it's powering.

The noise from it was terrible, and if I was a neighbour I would complain if I had one sited near me I'm afraid, and I couldn't live with the racket which carried quite a distance.

I wondered if anyone else had any experience of this.


Also - connected with this:

http://environment.guardian.co.uk/energy/story/0,,2044398,00.html

 

[Nemesis]

Ooops:

http://news.bbc.co.uk/1/hi/uk_politics/6505807.stm

 

[Penners]

How small is small? Your experience with the noise from the one near the boathouse is interesting, and makes me wonder whether this is a case of "the smaller the noisier".

I think I posted in another thread recently about the turbine that's just been put up at a nearby pub. It's a 6kW job, and I have to say that the noise from it - while audible up to about 100+ metres away on a windy day - is far from loud, unpleasant or disturbing. It's just a soft whirring sound. I quite like it. (But then I also love the sound of an old Fordson diesel tractor on tickover, so maybe it's me...!)

For what it's worth, here's a theory. The smaller the device, the lower the mass of its turbine, and the lower the resistance to revolution. So the little thing whizzes round like a fart in a colander, and the blades therefore have a much faster tip speed - thus noisier.

A larger turbine is the reverse: higher resistance to revolution, slower revolution, so less noise.

That theory is complete guesswork and has certain weaknesses; e.g. the larger turbine also has a greater diameter, which would tend to increase tip speed, but it all depends how the equation balances out.

Maybe someone who knows what they're talking about will give us a definitive explanation (and tell me I'm talking blx).

I wonder what's happened to Jane recently. Her views on this would be interesting.

 

[Flyfisher]

Those fast-whizzing wind turbines on some yachts have never seemed too noisy to me, but maybe the wind and water noise overrides it a bit?

I don't think it's the mass of the turbine that directly affects its speed (acceleration/deceleration perhaps), I think that's more to do with how much power is drawn from the generator, which acts as a brake. Bit of a guess though - any turbine engineers out there?

 

[skier-hughes]

WHAT YOU SAY Mike?

 

[Nemesis]

It was I think about three to four feet across on a pole - the noise was a whipping noise and quite disturbing. Quite a small one really I suppose. I wouldn't want it near the house.

 

[Penners]

the generator, which acts as a brake.

Ye, that's what I meant by "resistance to revolution". The higher the capacity of the genny, the greater the resistance.

Dunno why I'm postulating this, really. I don't have the slightest idea what I'm talking about. :roll:

As usual.

 

[Flyfisher]

the generator, which acts as a brake.

Ye, that's what I meant by "resistance to revolution". The higher the capacity of the genny, the greater the resistance.

Sorry, I was referring to the "mass of its turbine"

Dunno why I'm postulating this, really. I don't have the slightest idea what I'm talking about. :roll:

Me neither, hence my appeal for a turbine engineer to put us out of our misery :wink:

 

[Penners]

I think we're talking about the same thing - or things. There's the physical mass of the armature (plus friction in bearings, etc) and the resistance of the magnetic field in which it rotates.

 

[NT]

I dont know either.

But I know that too often these little turbines take more energy to make and fit than they return, making them wasteful consumption in such cases.


NT

 

[AMc]

Unless you don't have an alternative but to wire into the national grid in which case they're a sound option - cheaper per watt than solar photo voltaics and will work day and night (though not all the time obviously).

If that turbine is connected to a battery and powers a low voltage system i.e. weather station, low voltage lighting etc. then it could well be the most efficient and cost effective solution for that site.

RE that solar link. In My Humble Opinion - Everybody overstates the power & performance of things they're selling from cars, stereos to washing up liquid - "lasts 3 times longer than ordinary liquid" etc. If you complain that you don't get the same miles to the gallon quoted in the car ad you won't get anywhere but for some reason some people expect certain companies to undersell their products. I doubt my oil fired boiler can meet it's rated efficiency or output, that doesn't mean the manufacturer lied I'm sure they could prove the figures just the real world is not a laboratory.
If you're buying microgeneration equipment then you need to do your own research not rely on the sales pitch from a single installer.

Back on topic, from what I've read about DIY wind turbines.
A turbine with poorly balanced blades will vibrate making it noisey.
Larger numbers of smaller blades seem to be more noisey than smaller numbers of larger blades.
A loose blade will make a lot of noise but probably not for very long

My guess is it is a very cheap, low power turbine doing something minor linked to 12volt battery. If it were sited somewhere where the noise was an issue it would be larger and better built but only Nemisis has seen it and we can none of us be sure.

Simple wind generators for simple applications...
http://www.gotwind.org/Projects.htm

 

[Nemesis]

Well it's a pity really as it's a local beauty spot full of wildlife (it has to do with a bird hide) and spoiling the tranquility. Two of us rather shocked by the noise it made - nothing to do with not balanced I think, simply to do with very high speed rotating through air. Far faster than the usual giant turbines which move relatively slowly - this was more like a propellor on an aircraft.

 

[Penners]

You're sure that your eyesight hadn't been affected by the home brew? Could it have been a DC3 about to take off?

 

[Nemesis]

Nope - def a turbine. Very very fast and noisy. Might scare the birds...

 

[dormouse]

Been thinking hard about a small one

Whether this is better than other renewables depends entirely on how windy it is where you live. Most urban environments are neither windy nor open enough. A turbine needs an average wind speed of 4 metres per second. Your local energy centre should be able to advise on the applicability of this technology where you live - http://www.energysavingtrust.org.uk.

As most energy used in a house is heat (ca. 15,000 units of heat, 5,000 units of electricity) the first step is always to minimise this loss. Of course, this presents its own challenges in a lot of period properties.

 

[Nemesis]

It's not urban here and pretty windy on the top of our hill!

The challenge in this period property re insulation has as the first line of technology thick clothing.

 

[Jane Smith]

Hello, all.

Sorry not to have been here: my son goes in for surgery next week (he was born with club feet, and is having an Ilizarov frame fitted to sort it out again) and I'm a little snowed under doing things like getting hold of a wheelchair, altering all his clothes so that they Velcro up one side so he can put them on over the frame, that sort of thing.

Our turbine is a 6kW Proven, probably the same kind that Penners has seen, woth rotor blades about 2m long each. It makes a whispering, whooshing noise which increases in proportion to the strength of the wind. It's not intrusive, nor whiney. I suspect the one Evelyn has heard is a smaller one, as they do seem much noisier to me.

I'd not bother with the smaller ones: they don't give you a good output, in my opinion. I've worked out that the one B&Q is selling for £1498 will give an energy saving equal to that of £17 of energy-saving B&Q lightbulbs. Hmmm. And very few of us live in wind-appropriate sites: it might be windy, but if that wind is turbulent then it might not be any good at all. And one person's idea of windy might not be anything like enough.

Average wind speeds in the UK are, I think, 5.4m/s, and our average here is 8.4m/s. In suburban areas the average often hovers around 4m/s because of the damping effects of the buildings. Just to give you an idea of what's what.

 

[Nemesis]

Saw another small one at the weekend, only yards from the house it belonged to. Again, noisy and I have to say that would drive me batty. It's OK if it's your own but I pity the neighbours! This was not in a place off the mains.

Interesting that you think smaller ones not worth it. I think with some the idea of 'being green' can make them cease to see the wood (which they could burn) for the trees.

 

[Jane Smith]

It's all about doing what's appropriate for your situation.

Just think how much insulating you could do for that £1,500, rather than buying a little wind turbine which won't ever really do much for you. Seems much better to me.

Incidentally, we heard today that our wind turbine installation has been shortlisted for one of the Yorkshire and Humber Microgeneration Awards. Not that we're feeling particularly smug or anything....

 

[skier-hughes]

I've heard B&Q are discontinuing the wind turbine due to far to much failure rate.