Do any of you have a windmill?

TreeFarmer · Heavy Crude Joined: Jun 26, 2007 Posts: 352

Do any of you have a windmill? If so, I'd like to get your take on them.

I'm thinking of getting one and using its electricity in the wintertime to partially heat my house. I live in PA so there is plenty of cold and usually plenty of wind in the winter.

What I was thinking about doing was just connecting it to some type of electrical heater and just let it make heat when the wind is blowing. I know this is nothing fancy, just something to make me a little more independent.

TF

Hagakure_Leofman

We used to have one, and the guy next door has one.

I like his system. The windmill pumps water from underground - up to a tank on the surface. The overflow then is piped back down into the ground. So it pretty much runs the whole time when it's windy.

Personally, if you can, gravity fed water from elevation is the best. Though a windmill can help with that, pumping it up into an elevated tank.

Of course, there is maintence, but a good one should last for years (provided your groundwater does).

WisJim

We have a wind generator, have had it in use since 1978. It generates part of our power, most of the rest comes from PV panels, some of which we have had over 25 years. Using wind generated electricity for heat is not usually the best use of the machine, as it is cheaper to heat with wood, coal, direct solar gain, or natural or LP gas. If you built a machine strictly for heating, it could be a bit simpler than one providing electricity useful as house current, but building a reliable machine takes time, skill, and money.

SchroedingersCat · Intermediate Crude Joined: May 26, 2005 Posts: 536

I used to work for WorldPower. We sold wind/solar combo kits. Almost always a combo. Use a combo of wind and solar to charge batteries to run an inverter. The one load we cautioned against was resistive electric heat. Not the best use. Fans to move air heated by other means was fine.

Small scale wind needs towers and open space to be efficient. Also a good average wind speed in your location. NREL has some good information to get you started: NREL's National Wind Technology Center

By the way, we sold our technology to Southwest several years ago. Look at the Whisper line. Good stuff.
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Ronin

I don't know much about it but an interesting idea I heard was to use a car alternator to charge a battery with the propeller attached to it.

We'll have plenty of alternator. Shocked

mos6507

I've read that alternator windmills are very inefficient. Maybe the low cost of that sort of DIY solution will offset that, but supposedly raising the windmill on a pole is a big part of the expense. You might as well put something decent at the end of it.

Anyway, when I think of windmills I think of fans, which are the inverse of windmills. The small windmills you see could never generate much more power than it would take to power a ceiling fan on a low setting. And that is just a tiny portion of a household load. So residential wind in a suburban setting is really a nonstarter. You'd have to keep the windmills so small and unobtrusive that they would only provide a trickle of power to the household. You need enough land area to support either a lot of small ones or one really big one for them to really make a difference.
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WisJim

This has been mentioned many times before, but for home-built windmills, the best info is from Hugh Piggott or from Otherpower.
Hugh Piggott
Otherpower

These home-built units are based on a home-built alternator in order to get usable amounts of power from a direct drive unit, avoiding the power losses of gear or chain or belt drives, which can be a large percentage of the power in a smaller unit. And, units based on these designs have been built all over the world for 10 years or more.

Want to take a class and build a unit with qualified instructors?
Class

Want to build a big one that might pwer everything at the homestead? (I don't know anything personally about these.)
Prairie Turbines
But they look like they should work okay.

My machine was commercially available in the 1940s and has worked well for me, and for many other people, for many decades, but they are harder to find these days.

HeavyFuel · Coal Joined: Jun 25, 2008 Posts: 4 Location: Pacific

I have been looking at the otherpower 10' mill for a few months now... to supplement the 4.5KW of solar I have on my roof. I like the simple design and even though I'm a diehard DIY'er, I probably will buy a pre-built unit from them very soon.. and from there attempt to build an additional one, follow the plans to carve sets of spare blades etc, that and the rotor/stator winding and casting is something I need to learn to do. I'd love to attend one of their seminars.. but not possible for me due to location.

Starvid

Jupidu

I'm an engineer but electricity never was my favourite subject, so i hope i'll describe things right:

You can use an alternator to power a electrical heating cartridge in a heat storage tank. So you don't have to shut off the windmill if the heat produced by the electrical heater gets too hot. The tank shouldn't be too big because with too much water you can't get high temperatures.

From a DIY-booklet ( Copyright for all pictures:
Christian Kuhtz, Hagebuttenstr. 23, 24113 Kiel, Germany):

Diagramm of characteristics of alternators and rotors with different diameters at different speed

With an alternator from Bosch (main supplier of automotive electric parts) 45A, 12V you can combine a 1,7m rotor and you will get about 110 W at 9 m/s (130W at 10m/s).
A special circuit with an extra capacitor (same alternator):
140W at 9m/s (180W at 10m/s).
At higher wind speed the rotor is more and more underchallanged. Underchallanged for a rotor means it will produce more noise. In the booklet is described a two-stage circuit to take better advantage of the rotor even with strong wind, but that's quite complicated circuit.

An alternator usually needs a high number of revolutions per minute, but with an adequate rotor for an alternator the speed should be a lot lower.
To achieve this, the number of windings in the alternator has to be higher. You have to open the alternator and replace the current wire with a finer one. There are also different types of windings for an alternator.

Mounting a three-pole-mast and how a simple ground anchor looks like.

Two pictures of a windmill mounted on a roof and one mounted with three poles on the earth.

To the rotor: In best case you have a profile in each blade which is winding from the tip to a point near the axis (more inclined near the centre than at the tip). The profile is like a profile from a wing of a plane but it is directed backwards (the lift goes backwards).
It's like you would mount a plane backwards on an axis but with one wing turned around by 180° on the vertical axis of the middle of a wing.

Bigger types can be built e.g. with parts of a washing-machine and an alternator from a truck.

criticalmass

Alternators/ stators robbed from automotive/ cycle industry are very inefficient by electric motor/ generator standards, but work and are durable. I'm of the thought that since so much effort is poured into raising a tower and storing the energy and converting that energy, the wind generator may as well be a good one. Fortunately you can build a good one! For the rest of us, I have indeed heard that Whisper makes good stuff. I'm looking into my own.
It does seem wise to have a wind generator or two supplemented by PV panels. Even then, using the electricity you are making on your own will need to involve conservation and efficient appliances.

WisJim

Whisper for the most part makes light weight machines that don't last for decades, the way machines from some other makers will last. I know quite a few people who have had serious problems with Whisper machines, and I don't recommend them when asked about available machines. The Proven, ARE, and Jacobs have shown to be quality machines, and the Endurance looks good too. NONE of them are cheap!! The only good cheap machines are homebuilt, using Hugh Piggot's or Otherpower's info, books, and websites. It will take a lot of work, though.