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Offline Wilbur

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Wind Power
« on: December 15, 2016, 03:57:19 PM »
Now if I know next to nothing on solar I Truly know nothing on wind power. But heck...a little google fu and I can be a dangburnexpert! Well..mebbe not a expert  :o.. but prob no less dumb than the idgits in DC passing laws spending our money giving tax credits to people who put up green energy stuff.  But I digress.  8)

But I've been somewhat aware of various wind powered turbines for a while now (actually since the 1980's when the local power company put a big windmill outside their HQ to show they weren't only interested in burning coal and oil to make electricity. My Dad (who worked for them) let me know the windmill didn't even generate enough electricity to power the light that lit it up at night....it was just a total PR move  ::) ) I also recently (in my work) looked at a vertical access version that was kind of interesting, but it hasn't gone anywhere either as their manufacturing costs are still too high.  But I have seen quite a few designs over the years.

So again, I know enough to be dangerous. But I thought I would at least throw down some ideas of what I know (or think I know) as I do think there may be some merits in certain situations for their use. Especially in the east where solar may not provide the same output as out west. Ultimately I don't think anyone should look at these in a grid tied system as a way to save money, I just think the payback is way too long. But for an off-grid scenario they may make some sense, again, if solar is not as good an option.

The other benefit of wind is that it can operate at night when solar can't. So in theory someone who had reliable winds to grab could get away with a somewhat smaller battery bank and solar array if they could get some re-charging done overnight or on cloudy days when their pure solar system wouldn't be helping. Is it enough to warrant the cost? I don't know....everyone's situation will be different, but it is a plus in my mind (the night time thing).

I welcome any disagreement or thoughts based on others knowledge and/or experience. I am posting this not because I think I know everything but really to stimulate discussion and see if others have other thoughts or ideas. But here's what I have:

1. Off grid systems seem mostly designed in the 1kw or so range and put out power in 12-48 volts for charging batteries.  The windmill can be alone with batteries or presumably hooked into the same system as solar panels that connect to the batteries but I am not the guy to ask how that is done! The power from the batteries (regardless of solar or wind generated) is then run through an inverter to power 120 v items.

2. Towers: Windmills need to be up above the trees to catch the majority of the wind and operate efficiently. To minimize turbulence it should be at least 30' above the trees, ground or whatever. Not only does the turbulence decrease the efficiency of the turbine it "tears them up" (that's a technical term us wind experts use at conferences but I thought I would share it with you  ;) ) and they wont last as long. The downside to this in my mind (in a SHTF situation or in a place where you just don't want to draw attention to yourself) is that everyone knows you are there if they can see a windmill.

One other thing to consider is to have a tilting tower as opposed to a stationary one (which for the most part off-grid versions are this type as the turbines are smaller). This way you can lower the turbine to the ground to work on it as opposed to having to be on the top of a swaying 100' pole trying to do work ("Hey I dropped my wrench!"  :o  I'll pass thanks!) This might be a benefit in a SHTF situation as you could theoretically raise the windmill pole only at night if you were really trying to be "invisible".

2. TURBINE TYPES
A. Horizontal axis: These are typical windmill turbines that have a propeller like device attached to a horizontally positioned rotating shaft.  These turbines seem to provide better performance efficiency than vertical axis units because the blades are always being pushed by the wind. Some efficiency is lost if you are in an area where the wind changes directions a lot requiring the head of the turbine to turn to be oriented to the wind. But in an area where winds are predominantly from one direction (which I would think would be most off grid scenarios) this shouldn't be an issue. The other thing about these types is the blades typically spin pretty fast and can be a bit noisy. Whether its enough to cause a problem will depend on where you have it obviously. With some of the big ones the turbulence can cause some people to get nauseous also, kind of like the cavitation when you have one rear window down in your car. I don't know if smaller units have this issue but I know a very large about 10 miles from me has caused a lot of problems with neighbors. For large ones also bird kills are an issue but I don't know if that exists with the smaller ones.   

B. Vertical Axis turbines. With these types of turbines the blade (or blades depending on the model) are standing vertically and rotate around a vertical shaft. There are a couple of different types of these- some are like a barrel cut in half then welded together so offsetting "sides" that "catch" the wind. Some are more open designs with three of four thin curved blades attached at the top and bottom. Lastly some look like a sail in a cylinder. These lose some efficiency versus horizontal turbines because the "blade" has to turn back against the direction of the wind to get to where the wind "pushes" it again. They all seem to have some alternative shape designs for the "blades" to minimize the friction on the "back stroke" but it still has an effect which reduces efficiency. However they appear to operate in lower windspeeds than traditional horizontal units but I am not sure if that is exclusive to larger ones. They also seem to rotate more slowly so they don't kill birds. I have seen some designs like this that are being contemplated to mount horizontally on the tops of buildings to catch air currents coming up the building face but I have never seen this actually done- but my point is there doesn't seem to be anything unique about the vertical axis- they just want the turbine perpendicular to the wind current. 

The costs seem to vary pretty widely with small versions that are used on sailboats to top off batteries costing a few hundred up to larger home based units costing a thousand/few thousand or more- as with anything its all about the wattage it puts out. Keep in mind this is just the turbine and not the other electronics or the tower.

Love to hear what others think about this and success (or failure) stories we might learn from.

Offline Sammconn

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Re: Wind Power
« Reply #1 on: December 15, 2016, 05:24:45 PM »
I have a 400 watt one at the cabin.
Thanks for pointing something else out I had forgot was on my 12 volt system lol.
I need to see if it can do 24, or if it too needs upgraded...

I think it is an 'Air X' or something of that sort.
It is on a relatively short (too short) tower about 40 feet.
Braced into the eave of the roof.

What I can tell you,
The blades spin incredibly fast when the wind does get it.
They would mince a bird, not sure if it has or has not happened.
It is physically small, 3 foot blade.
The resonance it places in the roof and then cabin will wake you at night.
If it were 10-15 feet higher it would likely do me more good. Trees in the way a bit.
I have a complete tower that it was going to go to, to get the noise off the house, now it may go for sale...

It certainly does provide me some power, unsold whether it's worth it for me or not
We don't have the steady required winds.
I just don't want to wind up missing a digit or limb.  I can sometimes get in a hurry to get results.
Sam

Offline TexasRedNeck

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Re: Wind Power
« Reply #2 on: December 15, 2016, 08:35:24 PM »
The SHTF scenario reminded me of a cell tower I saw somewhere. They had disguised it as a tree. Albeit a really big tree. Not sure if a vertical axis turbine could be made to look to be a part of the tree trunk and a faux tree top above it. Tilting towers are good to have. Same for ham antenna.


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Offline Bob Smith

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Re: Wind Power
« Reply #3 on: December 15, 2016, 09:24:20 PM »
There is a tower looking like a palm tree just down from our place in AZ. Actually doesn't look too bad except for the antennas sticking above the body of it.

Offline TexasRedNeck

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Re: Wind Power
« Reply #4 on: December 15, 2016, 09:29:09 PM »
I think it was in AZ that I saw it, come to think of it.  Scottsdale area?
Kids today don't know how easy they have it. When I was young, I had to walk 9 feet through shag carpet to change the TV channel.

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Offline Wilbur

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Re: Wind Power
« Reply #5 on: December 16, 2016, 08:56:45 AM »
There's one of those cell phone pine trees near me....pretty funny as it stands about 50' higher than all the other trees near it. No mistaking what it is. The best "disguised" one I've seen is a huge flagpole nearby...it's really tall but the thing that confused me was why it was so wide....much bigger than what is needed for the height of the pole...turns out the shaft has cell phone antennas in it. That it flies a 50' or so flag is just a bonus! :)

 

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