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Micro Wind Turbines


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#1 MikeGraham

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Posted 23 September 2015 - 10:10 AM

This still seems a very quiet topic here in the UK, and I wondered if anything had changed since it was last visited?

I appreciate that on a small scale, its never going to produce an epic amount of power, but was thinking more of a top-up to go with the Solar PV.

Looking on eBay there are UK sellers selling 400W turbines for about £150, not including all the other bits you likely need, and they work from as little as 2.5m/s wind. How likely is this to provide any decent amount of power?

Having a 4kWp Solar PV array, would I be going over the G83 thing I've seen people talking about? Would this be able to tie into the sunnyboy inverter where my Solar PV is connected to if it has a 3rd phase?

Its probably a none starter, but just thought it worth revisiting.

http://www.trueshopp...-Sheet-Copy.pdf

Mike

#2 SteamyTea

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Posted 23 September 2015 - 10:24 AM

With micro-tubines you really need to have them connected to a battery system, via a charge controller. This is mainly because they rapidly spin up and spin down in gusty conditions. A SunnyBoy can't cope with this. SMA used to make a WindyBoy, but have stopped now as far as I know (I spend two very cold days in a shed trying to reconfigure one once).

The other thing about micro-tubines is that they dish out very little power. Cutting in at 2.5 m.s-1 just means they are generating something, nothing like the maximum rating. That will be at much higher windspeeds. So high generally that that they really happen for any length of time.

I was at a place on the weekend that had an Eclectic Energy turbine, http://www.duogen.co.uk/, the owner spoke highly off it, but I did not ask what the annual yield was. Probably not much if the truth be known.

You could directly connect one to a resistance heater of some sort, just let it store thermally when it is generating. Jeremy knew someone that did this, they used a pile of rocks and rubble in the building as they store.

Edited by SteamyTea, 23 September 2015 - 10:26 AM.


#3 DamonHD

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Posted 23 September 2015 - 11:01 AM

If you're in a built-up area, don't do it, the wind will not be good enough. (Unless you're in Stornoway's neck of the woods or otherwise have trees that grow sideways.)

If you're in a rural area and can put the turbine 10m up at least, and 30m from any significant obstructions, then generation conditions could be good.

Have a look at fieldlines.com (on which I am a mod) which exists to talk about small wind gen, but where I'd say a majority would now suggest PV first in most situations, from a generation and maintenance point of view.

I experimentally had one in my garden, which I am doing without this winter, and I think it was not even turning 1% of the time, never mind contributing significant energy, whereas I generate many megawatt-hours per year from a grid-tie PV system and run an entire server system off a separate off-grid PV system, in our small suburban plot.

Go into it with your eyes open.

Rgds

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#4 MikeGraham

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Posted 23 September 2015 - 11:05 AM

Indeed. Well we already have solar PV, and that's fantastic, I knew the turbines were low efficiency years back, and wondered if they'd improved on them any. We live in an area with bungalows, and the wind blows fairly strongly, though probably not strong enough to make a decent impact.

#5 Mackers

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Posted 23 September 2015 - 11:08 AM

I liked the idea of wind but it seems it has a lot of opposition. It definitely is not as useful as PV. I like the idea of micro-hydro if you have a suitable river or stream on your property. This rules most places out though.

#6 MikeGraham

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Posted 23 September 2015 - 11:13 AM

Yeah definitely no streams or rivers in the vicinity! lol

#7 jsharris

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Posted 23 September 2015 - 02:25 PM

The problem with wind is that the energy density is very low and proportional to the cube of wind speed. This means that in most of the UK, where winds are, on average, pretty low, you simply can't get much energy out unless you intercept a large cross section of moving air.

Large wind turbines have a very much wider range of working wind speeds, because of the ratio of fixed losses (friction etc) to output is much smaller, but even the very best can only extract around 50% or so of the potential energy in the wind. There is a hard limit with efficiency that has nothing to do with electrical or mechanical design, but is imposed because to work, a wind turbine has to have air flowing through it, which means the air must still be moving on the downwind side. If the wind turbine could somehow absorb all the energy in the moving air, then the air would be completely still on the downwind side.

Using aerodynamic devices, be they rotating blades in any form or sails or whatever, relies on there being moving air, so this type of device, in any form, can never extract all the potential energy. If you came up with a device that didn't use aerodynamics, but somehow managed to intercept an area of moving air, stop it dead and extract all the energy out of it, then you could probably double the efficiency of wind turbines. No one has done this yet, though.

Edited by jsharris, 23 September 2015 - 02:26 PM.


#8 tonyshouse

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Posted 23 September 2015 - 03:19 PM

There are some very nice silent small ones being made near Oxford and exported to Europe, ex F1 designers.

Get them if you need one, silent is remarkable!

#9 joe90

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Posted 23 September 2015 - 03:21 PM

I wish the one near me was silent!

#10 joiner

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Posted 23 September 2015 - 04:25 PM

:D

#11 SteamyTea

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Posted 23 September 2015 - 04:39 PM

Care to post a link Tony.

There are lots of ex F1 designers. The good ones are still doing it :D

#12 MikeGraham

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Posted 23 September 2015 - 05:20 PM

Comprehensive replies, but I think the general consensus is to leave wind to the big windmills, worth revisiting tho!

#13 MarkH

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Posted 10 March 2016 - 07:25 PM

I've got a 600W turbine installed as part of an off-grid system. I started last summer with PV but then the sun disappeared in October and didn't show it's face again for months. In late November we reached the point where our battery bank was getting dangerously low and bought the turbine. It has been brilliant.

Whilst wind turbines are not as efficient as PV they work - when it is windy - for 24 hours a day and that, I think, is their main advantage in a climate like we have in the UK. Because turbines need to be under continous load the surplus power needs to be used, in our case the dump-load is a heating element in a water tank.

Would I have installed wind if we were grid connected? Probably not.

#14 jsharris

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Posted 10 March 2016 - 09:52 PM

600W is a pretty big turbine, though, and certainly not a micro turbine by any stretch. Once you get to this sort of size, in a decent location, you can get a serious amount of energy, but the small micro things are little better than toys, IMHO.

#15 declan52

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Posted 10 March 2016 - 10:26 PM

Seen a report about Renewable energy generation in NI and wind accounted for 90% of the total generated with PV only at 1%. So wind must be a viable option but unless the cost of the turbines comes down it won't be as popular as fit and forget PV.

#16 MarkH

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Posted 10 March 2016 - 11:52 PM

View Postjsharris, on 10 March 2016 - 09:52 PM, said:

600W is a pretty big turbine, though, and certainly not a micro turbine by any stretch. Once you get to this sort of size, in a decent location, you can get a serious amount of energy, but the small micro things are little better than toys, IMHO.

1.55m diameter blades, so not tiny I guess. I'm not sure what constitutes 'micro' although I have seen 1KW units described as such. I think their usefulness depends very much on your requirements and of course the quality of your site.

#17 joiner

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Posted 11 March 2016 - 07:03 AM

Mark, does yours make ANY noise?

#18 MarkH

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Posted 11 March 2016 - 09:59 AM

View Postjoiner, on 11 March 2016 - 07:03 AM, said:

Mark, does yours make ANY noise?

Yes, it's not silent. We don't find the noise offensive though, its a swishing kind of sound. As the wind increases it gets louder but you probably notice it less as the wind through trees etc nearby is louder.

I don't think our turbine is the quietest available, we chose it because it has a low visual impact as much as anything - it is a downwind model with no tail boom made by a company in mid-Wales.

#19 Alphonsox

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Posted 11 March 2016 - 10:06 AM

Any pictures or links ?

#20 DavidWright

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Posted 11 March 2016 - 10:07 AM

View PostMarkH, on 10 March 2016 - 07:25 PM, said:

It has been brilliant.
Your approx. location in the UK, and the openness & aspect of your site are probably very relevant factors.