Connecting Wind Generator to Heater

System

I have a lake property which I only use in the summer. In the winter we have high winds and I was wondering if I it is possible to have a small wind turbine connected to a heater so as to create heat on windy days. It matters not if the heat is consistent.

Is it possible to have the wind turbine connected directly to an electric heater.

This could be my first project to introduce m to wind power so I was hoping to keep it simple.

BB.

Re: Connecting Wind Generator to Heater

If you are looking at installing a HAWT (horizontal axis wind turbine), the answer is is that it probably would not be practical/cost effective... You cannot connect a HAWT directly to a resistance load (electric heater) and get optimum heating without using a battery bank + shunt charger in between.

Wind turbines vary RPM / output voltage / output current a lot. You would have to size the resistance/watt rating of the heater to your maximum wind (perhaps 40+ miles per hour), and then it would operate very inefficiently (as a heater) at your normal 10-15 MPH that most "good wind" sites have as average wind speed.

Have you thought about installing a solar thermal array instead? If you are looking for 9+ months of water heating in a good sun area--The starting rule of thumb is ~20 square feet per person for hot water.

Solar Thermal panels will be much cheaper and, probably, be more reliable/less costly overall than a wind turbine based electric hot water system.

Winter may be a bigger issue (subfreezing weather? Poor sun due to weather?), but even in freezing climates people have build solar thermal systems for home heating.

Solar Thermal can be a nice source for space heating and hot water... And usually is "cheaper" per kWhr/BTU vs Solar PV Electric/wind turbines. Also, Solar Thermal lends itself very well to do it yourself projects. Note, these are plumbing projects and have their own issues (leaks, pump failures, installation issues trapping air, anti-freeze, storage, heat exchangers, etc.):

Solar Shed and other Solar Thermal Links

A good place to start reading is Home Power Magazine... They have a free past issue online--and have a lot of articles you can read for free. I don't always agree with them and their reviews--but they are a fun and enlightening read:

Home Power Mag

-Bill

Cariboocoot

Re: Connecting Wind Generator to Heater

Welcome to the forum.

Yes, it's possible. How practical it is ... that's different.
For one thing electricity is not a very efficient way to heat things. You may find it doesn't provide enough heat to be worth the effort and expense. And there will be considerable amounts of both.
The #1 problem with wind power is that the site isn't really suitable for it, despite appearances. Turbines like sustained 20+ mph winds for good output. That's a lot of wind. They don't like light breezes which produce nothing nor gusts which spin them up and down and put terrible stresses on them.
The #2 problem is that most of the small wind turbines available are quite frankly junk. They don't produce anyplace near their rated values and they tend to fail fairly quickly and easily.
The #3 problem is the installs don't follow directions. You really do need it up in the air, away from turbulent winds. Lots of clear, open space. And a firm mast with guy wires all well anchored so the whole thing doesn't come crashing down around your ears - and possibly through your skull.

Otherwise, the idea of a turbine feeding a resistive heating element isn't uncommon at all; it is the typical "dump load" required on systems used to charge batteries. Once the batteries are full you need something to do with the continued energy production so that the turbine doesn't over-speed and fly apart. Sinking the excess Voltage to a water heater is quite common.

Keep in mind this would be very erratic and uncontrolled heat, as there would always have to be some element connected to take the power for the reasons mentioned above. No thermostats; it could conceivably get quite warm.

System2

Re: Connecting Wind Generator to Heater

@BB: >>If you are looking at installing a HAWT (horizontal axis wind turbine), the answer is is that it probably would not be practical/cost effective... You cannot connect a HAWT directly to a resistance load (electric heater) and get optimum heating without using a battery bank + shunt charger in between.


Your claim is unsubstantiated. Battery banks and chargers are hideously inefficient, while nothing could be more efficient than pushing the DC or AC directly into heating coils.

The question is how much heating would you get? Would you need 30mph winds just to warm up a space heater? Would those same winds instead cause that same space heater to catch fire or otherwise burn out?

I think that with some control circuitry to switch in additional loads, first with the baseboard electric heaters, then an electric water heater, and then perhaps extra additional banks of room heaters, and possibly after that a trickle charger for batteries.

I have the same idea, and only want heat. I don't want to cut my electricity bills. I want to cut my Propane heating bills.

Solar and wind are complementary and a good strategy is using both. But, given that nighttime winds are the first choice for an energy source for home heat, I am of the same mind as the poster. It's great to see someone else with the same idea. Thanks for posting. Now let's get some real answers, rather than simple diversions.

Cariboocoot

Re: Connecting Wind Generator to Heater

jmar;

Did you read post #3?

Bill's comments are not "unsubstantiated" they are factual: in order for a heater to function properly as a heat it needs a consistent power supply to draw upon as needed, so that it may turn on and off in accordance with the demands of heating the area. Otherwise you would simply be dumping random amounts of heat into the room. Heaters do not work correctly with low or varying Voltage, as the elements are designed to function at a particular Voltage and current level. The conversion rate is not linear, so supply 1/2 the Voltage does not produce 1/2 the amount of heat or even 1/2 the amount of Watts (the resistance value of the heating element changes with its temperature).

As for what you could actually expect from running a wind turbine directly to a room heater, the answer is: trouble. Say you have a turbine rated as 500 Watts @ 20 mph. Also say you've got the 20 mph wind consistent enough to sustain the power output. You feed that to a 500 Watt heater. Leaving aside the drop in output caused by Voltage difference (the Watts may be the same, but the heater is likely 240 VAC whereas the turbine's output is more probably 24 VDC) a 500 Watt heater won't heat much space. Most room heaters are 1500 Watts, so you would either need a very large turbine or some multiple of small ones just to power one heater.

You would not have to worry about over-heating it, because heaters have built-in thermal protection which prevents this. That means the connection will be broken if the heating element gets too hot. That also means the wind turbine will suddenly be unloaded, just as it would with a thermostat disconnecting, which is when they can over-speed and come apart. There would have to be a diversion load control on the turbine to keep it loaded at all times, perhaps switching power out to other heaters. This gets complex.

Then there's another problem; the turbine's output is likely DC, whereas the heaters are meant to run on AC. Even on lower Voltage, the controls will not handle DC well. They may arc and burn leaving them permanently disconnected or they may weld themselves shut leaving the heat on all the time. This includes the thermal safety. If the Voltage is at the right operating level for the heater (120 or 240 Volts) the damage to the controls is certain to happen.

When people use heating elements for dump loads they are only used when the batteries are full; not all the time. DC rated switching is employed, and there is no need to gain "real heat" so much as to be sure the turbine stays loaded. Most often the heating is of water, where there is a significant mass to sink the energy to and little danger of over-heating of the element.

To repeat my original statement, yes it can be done. But after looking over some of the difficulties involved as outlined above you can see it is not really a practical solution to heating. It is hardly likely to be economically feasible. The money would no doubt be better spent on improving insulation, stopping drafts, et cetera. It nearly always is. Propane is actually a very good value per $ for heating, unlike any form of electric.

How's that for "real answers"?

john p

Re: Connecting Wind Generator to Heater

simple solution . cost negligable
connect in series and parallel some(lots??) 5w resistors and place them under a metal plate then put your feet on the plate and at varing times you will have nice warm feet. no disconnect from wind generator problems:p

BB.

Re: Connecting Wind Generator to Heater

Adding to Marc's post above:

jmar wrote: »

@BB: >>Your claim is unsubstantiated. Battery banks and chargers are hideously inefficient, while nothing could be more efficient than pushing the DC or AC directly into heating coils.

Battery banks are actually pretty efficient running from 80% to 98% (depending on battery type and how it is operated).

The question is how much heating would you get? Would you need 30mph winds just to warm up a space heater? Would those same winds instead cause that same space heater to catch fire or otherwise burn out?

People "run heaters" all the time with wind turbines as shunt loads (keep battery bank from over charging) and/or as "emergency" loads to prevent the HAWT from over-speeding if there where no loads (battery fully charged, circuit failure, etc.).

I think that with some control circuitry to switch in additional loads, first with the baseboard electric heaters, then an electric water heater, and then perhaps extra additional banks of room heaters, and possibly after that a trickle charger for batteries.

From a first approximation, power is:

• Power = V*I = V^2/R = I^2*R

So--you can see, if your voltage varies by a factor of two--assuming a fixed resistance, the power will vary by a factor of 4--Same thing with current.

So--it would take a fair amount of electronics (or load switching) to attempt to keep the wind turbine matched with it loads (not too big, not too small).

I have the same idea, and only want heat. I don't want to cut my electricity bills. I want to cut my Propane heating bills.

IF, (a "big if";)) I was forced to design an efficient wind based heating system... I would use a Wind Turbine + a MPPT type charge controller (Midnite Solar said they can get something like 2x the power from a wind turbine with properly designed/configured MPPT charge controller like their "Classic" system), a Battery Bank, and a Mini-Spit heat pump (16-26 SEER) and/or a Heat Pump based electric water heater (~2x as efficient as pure resistive heating).

So, the losses of the battery bank (80% worse case), charge controller (95%) and the 2x more efficient heat pump--and 2x wind turbine output with an expensive (MPPT) controller:

• 0.80 batt * 0.95 inverter * 2 heat pump * 2 wind turbine = 3x more efficient with "high tech" system

To run "high tech" heat pumps directly from a variable power source (solar, wind, etc.) at maximum efficiency could possibly be done--But nobody is doing it today.

Solar and wind are complementary and a good strategy is using both. But, given that nighttime winds are the first choice for an energy source for home heat, I am of the same mind as the poster. It's great to see someone else with the same idea. Thanks for posting. Now let's get some real answers, rather than simple diversions.

So, a "simple" resistive load connected wind turbine would generate less than 1/3rd (possibly much less than 1/3rd) as the same wind turbine with MPPT controller + battery bank + heat pump based "heating".

May still not be cost effective--but it would work (assuming the wind turbine performs well).

Again, not trying to stop anyone from experimenting--But suggesting that do a little work with pencil and paper first before spending the time and money to build a working prototype.

-Bill

The Only Sarge

Re: Connecting Wind Generator to Heater

I won't get into "efficiencies" etc. here and am not advocating anything.

I will share with the original poster my "experiment" in the barn.

The barn is on top a hill. Fairly constant breeze up there and I needed some lights etc. So I wanted to experiment with wind and solar this time.

The business driver was to have one small (100 watt equivalent CFL light burning about 25 watts) outside light, a 4' florescent light in the feed area and a plug in outlet for whatever. The outside light is driven by a on-off at dusk/dawn socket. Nothing difficult here and very low power usage.

I had some leftover harbor freight panels totaling 90 watts from my beginner days
Got one 12v deep cycle 125 amp battery and a 40 amp wind/solar controller a 150 watt small wind generator and a dump load "heater".
For the inverter I got a el cheapo ChinaMart 300 watt inverter.

Bottom line is the barn lights are used so little and the nighttime light draws so little the battery stays charged and the wind generator pretty much stays in dump. The resistors (2 100 watt) put out some heat. Now it is a little difficult for me to tell how much heat they put out as the barn is around 100f during the day....but you can feel the heat from the resistors when you get within a few feet of them.

So to the original poster...is it doable...yup....inexpensive....yup....how much heat....I dunno....but it puts out heat.

I will comment on the lil wind generator.....I thought it would be toy quality....nope...it is tough/solid and built very well.

Take all of this for what it is....just sharing my experiment and maybe it will add some value to what the original poster is looking for and maybe not.

GreenPowerManiac

Re: Connecting Wind Generator to Heater

Oh Geez, here we go again.....

My setup is as follows: 4 PMA's wired 3 phase A/C to the rectifiers within 2 feet of each battery bank. I hook up all my turbines after the diodes, D/C straight to the batteries. Any extra power produced from the array(s) is a diversion load to a D/C output. In my case a small fridge/heater box, whichever I choose. That about sums up the heat production from the turbines. Now, to make things simpler, I'd set up a row of small heat lamps (NON-CFL bulbs) direct from the turbines for heat.

I'm aware that it may be illegal to use non-cfl bulbs in California.

ggunn

Re: Connecting Wind Generator to Heater

GreenPowerManiac wrote: »

I'm aware that it may be illegal to use non-cfl bulbs in California.

I understand the thinking behind such legislation, but it's a baby-with-the-bathwater approach. Incandescent bulbs are a cheap, convenient low-intensity heat source for things like protecting plants from freezing in cold weather. CFL's are useless for that.

BB.

Re: Connecting Wind Generator to Heater

It is really strange out here (California)--I was looking for heat lamps (~120-250 watt red or white colored filament reflector bulbs)--typically used on lunch counters and bathroom heater/ceiling vents... And they are no longer at the local hardware stores--It is frustrating.

I have no issues with being offered choices--but having them shoved at me--I don't like.

When the leaders of our country stop flying government 747's and 757's for personal use--Then I will believe we have an energy crisis.

-Bill

Cariboocoot

Re: Connecting Wind Generator to Heater

Canada has "outlawed" incandescent bulbs. People ran to the stores just before the legislation took effect and bought whatever they could, pending the threat of never having Edison's best idea available again.
Except that it only applies to 75 Watts and up, and then not to "special application" bulbs like heat lamps or floods. Nor does it apply to halogens.

In other words they are "saving the world" by eliminating a bulb that few people used anyway.

Sometimes our Government's unending capacity to not understand an issue works.

GreenPowerManiac

Re: Connecting Wind Generator to Heater

Outlawed ?

Are they using them to grow certain weeds up there ?

I got so many incandescent bulbs, could possibly sell some in the black market..lol...

Didn't know they're worth anything...

solarvic

Re: Connecting Wind Generator to Heater

BB. wrote: »

It is really strange out here (California)--I was looking for heat lamps (~120-250 watt red or white colored filament reflector bulbs)--typically used on lunch counters and bathroom heater/ceiling vents... And they are no longer at the local hardware stores--It is frustrating.

I have no issues with being offered choices--but having them shoved at me--I don't like.

When the leaders of our country stop flying government 747's and 757's for personal use--Then I will believe we have an energy crisis.

-Bill

Bill, What are people suposed to use in a brooder for chickens? I have raised a few chickens from the egg and you need the heat lamps to keep the little chicks warm for the first few days or weeks of thier life deprnding on the temperature where you keep them. Maybe you can find these heatlamps at a farm supply store such as tractor supply. :Dsolarvic

BB.

Re: Connecting Wind Generator to Heater

Probably would have to drive two hours to find a farm supply store. If they have not gone out of business due to water cuts to farms. The California central valley has been hit hard.

I have a few saved to put in the bathroom vents as needed.

Went looking for an electric stove burner replacement switch. Appliance stores went to for decades are gone. Only one in ten miles looks to have one foot in grave. $12 part on web with $8 shipping, $20 list price from GE. Local dealer $41+10% sales tax. Guess where my money went.

Not too worried about finding bulb-just think this stuff is getting really stupid/scary.

-Bill

mike95490

Re: Connecting Wind Generator to Heater

BB. wrote: »

Probably would have to drive two hours to find a farm supply store. If they have not gone out of business due to water cuts to farms. The California central valley has been hit hard.

But the Delta Smelt (little minnow fish) are safe. That's where all the water that went to the orchards went to. Hundreds of square miles of dead trees, and cropless crop land. Fresno and Bakersfield are nearly ghost towns.

BB.

Re: Connecting Wind Generator to Heater

Yea, and the Delta Smelt, may not be, a species native to California either--but an invasive species or hybrid?

History And Status of Introduced Fishes In California, 1871 – 1996

Wakasagi, Hypomesus nipponensis McAllister

The taxonomy of this species has been confused. At present we follow Kljukanov (1970) in using this scientific name, and in California the wakasagi has usually been called the "freshwater smelt." Moyle (1976b), on the other hand, considered this introduction to be a subspecies (Hypomesus transpacificus nipponensis) of the native delta smelt.
Whatever the name (scientific or common), the same fish, then thought to be the pond smelt, Hypomesus olidus, was introduced "experimentally" from Japan to six waters in California in 1959 by the Department of Fish and Game.
At the time, this fish was considered to be native in California, resident primarily in the Sacramento-San Joaquin Delta, but difficult to secure. Reliance on a Japanese source was therefore made, and on 10 and 31 March 1959, air shipments of its eyed eggs on palm-fiber mats were received in San Francisco. The eggs were sent from Tokyo but had been taken at Suwa Reservoir about 70 miles to its east where they had been spawned artificially. Upon arrival, many of the eggs were dead, but enough were alive to furnish sizeable plants. Approximately 3,600,000 eggs had been shipped, but the number actually going into each of the six test waters was unknown: tributaries of Dodge Reservior, Lassen County; Shastina (Dwinnell) Reservoir, Siskiyou County; Freshwater Lagoon, Humboldt County; Spaulding Reservoir, Nevada County; Jenkinson (Sly Park) Reservoir, El Dorado County; and Big Bear Lake, San Bernardino County.

Trying not to take thread political (not for this forum)--Just some background information one why filament bulbs are getting difficult to find in California.

-Bill

PS: I remember going to a place names Ranch Wholesale near Stockton CA--I was probably still in high-school at the time (early 1970's)--Imagine a huge Costco or Sam's Club stuffed with anything a farmer may need from Tractors to huge glass syringes/needles on pegboard displayes and a free hot chocolate/coffee machine.

Cariboocoot

Re: Connecting Wind Generator to Heater

GreenPowerManiac wrote: »

Outlawed ?

Are they using them to grow certain weeds up there ?

I got so many incandescent bulbs, could possibly sell some in the black market..lol...

Didn't know they're worth anything...

Oh grow-op stuff you can get, no problem!

But soon the Green Police will be executing search warrants to find those nasty 100 Watt incandescent bulbs that are destroying the world!

I just tried to get some LED bulbs for the kitchen light. Nope. $18 each for 35 Watt LED or $18 for a pack of six 50 Watt halogens. Guess what I bought? :roll:

GreenPowerManiac

Re: Connecting Wind Generator to Heater

What about heat lamps ? Same as Incandescent ?

BB.

Re: Connecting Wind Generator to Heater

Heat lamps seem to be AWOL at our local MegaMart hardware stores (at least last time I wandered around with nothing to do:roll:).

-Bill

GreenPowerManiac

Re: Connecting Wind Generator to Heater

Was considering one of those D/C circulation fans that have the transformer adapter properly removed and wired. Not a reliable heat source; however, may be able to set up to run a low volume ceiling fan blowing down....

djkorn1

Re: Connecting Wind Generator to Heater

OK. I have read this thread and am thinking of using this to help heat a 3 car GARAGE. (heat does NOT have to be consistent, doesn't matter if it has no heat sometimes and gets up to 80 degrees other days). Our winters range from 40 degrees in Cleveland to 0 degrees. Pretty consistent winds because of Lake Erie, but NO sun in winter, due to Lake Erie clouds.

What about hanging a an old restaurant warmer from the ceiling with an old flourescent tube light deflector and have it hooked up directly using DC.

1) Could a 500W turbine overpower a 1000W heater? (no need to dump power right?)

2) If I run it DC, wouldn't it be more efficient? Even if it bumped it up 20 degrees, it would make it so I can work on snowmobiles/4wheelers. This is my brothers idea, but I am trying to see if anyone has done it successfully.

Cariboocoot

Re: Connecting Wind Generator to Heater

Welcome to the forum.

The one drawback you have with powering a resistive heating element directly from a wind turbine is that you have no control over when it makes heat or how much it makes. This means not only can it fall short, it can also be too much. So unless you take it down when you don't need it - you get lots of heat in Summer. The thermostats meant for AC heaters will not handle DC at the same Voltage even if you did have an alternate load to dump to. It all gets to be a bit problematic and tends not to be worth the investment for what amounts to random influxes of heat.

A 500 Watt turbine can't "over power" a 1000 Watt heating element. The output will be even less, in fact, because the turbine will probably not operate at the same Voltage the heating element is designed for.

Direct DC from DC generation could be considered "more efficient", but in reality all generators are AC on the inside so skipping the rectifiers would be even more efficient than just skipping the inverter.

On the whole it's a pretty "iffy" way to get heat.

NorthGuy

Re: Connecting Wind Generator to Heater

djkorn1 wrote: »

OK. I have read this thread and am thinking of using this to help heat a 3 car GARAGE.

I don't think that 500W wind turbine can provide enough heat to be noticeable in a 3-car garage.

djkorn1

Re: Connecting Wind Generator to Heater

Cariboocoot wrote: »

Welcome to the forum.
So unless you take it down when you don't need it - you get lots of heat in Summer. .

Thanks for the quick replies. Is there a way to put a 'lock' on a turbine in the summer to just stop it from spinning? Sorry, I am a complete newb, but trying to get an idea if this would work. It is mostly for fun and it would look cool on the top of my garage!

NorthGuy wrote: »

I don't think that 500W wind turbine can provide enough heat to be noticeable in a 3-car garage.

Even running 24 hours a day? Thanks for the reply.

djkorn1

Re: Connecting Wind Generator to Heater

My brother has 'also' talked of constructing a DC only vertical turbine using a motorcycle stator ran directly to the restaurant heater. Not sure if this would make the heat output higher?

We already have a bunch of stators and flywheels laying around from blown up motorcycles.
We have the restaurant heater that we got for free.

How much more is needed to make the straight DC system just for a test run? I know this is a completely different topic, but I am guessing there are a lot of experts on here.

Cariboocoot

Re: Connecting Wind Generator to Heater

djkorn1 wrote: »

Thanks for the quick replies. Is there a way to put a 'lock' on a turbine in the summer to just stop it from spinning? Sorry, I am a complete newb, but trying to get an idea if this would work. It is mostly for fun and it would look cool on the top of my garage!

Some turbines do have a mechanical brake to stop them, and furling to prevent over-speed. Depends on the design. Relying on it is a matter of how much of a gambler you are.

I don't think that 500W wind turbine can provide enough heat to be noticeable in a 3-car garage.

Even running 24 hours a day? Thanks for the reply.

With such a "direct drive" system the heating element will only heat when the wind blows. Does it blow 24 hours a day at a steady speed to keep the heat on? That's the problem with having no batteries to store up power when it is produced and then use it as needed.

Cariboocoot

Re: Connecting Wind Generator to Heater

djkorn1 wrote: »

My brother has 'also' talked of constructing a DC only vertical turbine using a motorcycle stator ran directly to the restaurant heater. Not sure if this would make the heat output higher?

Two things:

All generators/alternators are AC. This is because they all produce power by moving a magnetic field past a coil (or vice versa). The magnet has a North and South pole, and each moves past the coil in the same direction. Since they are polar opposites, one cause the current to flow one way and the other causes it to flow in the opposite way: Alternating Current. This is then converted to DC either by solid state rectifiers or by the positioning of brushes on a commutator (old style generators). As such, taking the AC directly from the coils is most efficient, albeit the frequency, Voltage, and current will all vary as a result.

Vertical Axis Wind Turbines (VAWTs) are the least efficient of all, as the blades have to turn back in to the very force which is trying to spin them. Different schemes have been concocted to reduce this effect, but you still end up with more turbulent air around the blades (in comparison to a horizontal style) and that reduces efficiency.

We already have a bunch of stators and flywheels laying around from blown up motorcycles.
We have the restaurant heater that we got for free.

How much more is needed to make the straight DC system just for a test run? I know this is a completely different topic, but I am guessing there are a lot of experts on here.

Go ahead. It will be a learning experience. Just don't sink a lot of time/effort/money in to it as what you are most likely to learn is that it is a waste of time/effort/money. Like DIY solar panels.

NorthGuy

Re: Connecting Wind Generator to Heater

djkorn1 wrote: »

Even running 24 hours a day? Thanks for the reply.

The turbine produces 500W when there's a steady wind of specified speed. Most of the time, it'll produce less, even if it's windy. There should be people with such turbines here who can tell more, but 100W average production looks optimistic to me.

When you turn on a 100W bulb 24/7 inside a 3-car garage (800-900 sf room with high ceiling, usually poorly insulated) will you feel that heat?

vtmaps

Re: Connecting Wind Generator to Heater

djkorn1 wrote: »

and it would look cool on the top of my garage!

You've been warned that small wind projects are almost always a waste of time and money. If you really want to compound your error, you attach your windmill to a building. --vtMaps

BB.

Re: Connecting Wind Generator to Heater

Here are some more wind links:

Wind Power Links
www.otherpower.com (good forum for DIY Wind Power)
Hugh Piggott - Scoraig Wind Electric site for tons of info (from mike90045)
Scoraig Wind "Recipe Book" for DYI Turbines (from Chris Olson... From his 4/11/2013 post)
www.greenpowertalk.org (added from "russ"--Like here but more wind/less solar)
Small windpower a scam ? Survey says SO
Truth About Skystream & SWWP
Windmax HY-2000 2kW Wind Turbine (apparently, some vendors don't sell spare parts--just new turbines. However, the owner, Edward has been very happy with its performance from 2010-2012--BB. 5/31/2012)

And a general DIY Solar Builder site:

www.builditsolar.com

ChrisOlson wrote: »

I always recommend Hugh's recipe book
http://scoraigwind.com/axialplans/index.htm

It has the "plans" on how to build six different turbines. But Hugh also goes into the theory in explaining why the turbines are built the way they are, and it's written by a master that has spent most of his life working with wind power.

I don't know about the Otherpower book - I have only read excerpts of it and never the whole thing.
--
Chris

ChrisOlson wrote: »

Ed Lenz's website is probably the best resource for building a small microturbine. Ed has articles on there covering three-phase basics, along with several small windpower projects he has done, etc.
http://www.windstuffnow.com/main/

--
Chris

The problem with connecting a heater directly to a "simple" wind turbine.... Imagine you have a gasoline generator that varies from an idle to 200% of rated RPM over a 24 hour period with no ability to time or control its operating conditions.

Connecting that to a heater where Power=V²/R -- Means that 70% of the time the heater has less than rated voltage on it (and since 1/2 the voltage squared is 1/4 the power) you get much less power out of it.

10-20% of the time the heater may have, roughly, rated voltage on it. And 1-10% of the time it may have 2x rated voltage (and 4x rated power) going through the heater.

You just are going to have very poor performance out of that sort of setup (i.e., very little average useful power from such a system, and a few hours a month or a year, the system will be trying to self distruct).

The power from wind varies with the cube (v³) of the wind speed. Wind speed below ~10 mph has almost no useful energy with a "small" wind turbine--No matter what that design may be. Many turbines are designed for "optimum wind" at ~20-25 mph. And in a 60+ mph wind, most will have to shut down for safety:

10³ = "1,000" units of power
20³ = "8,000" units of power
25³ = "15,625" units of power
30³ = "27,000" units of power
60³ = "216,000" units of power

Designing a wind system that can safely operate and supply "usable" power over a 216:1 range of power is not easy.

It is possible to design a electronic controller that can take variable current/voltage from a wind turbine and supply regulated voltage/current to a heating element to get "optimum" heating (based on available wind power). In fact, there are off the shelf MPPT Wind Controllers that can make that "regulated" power available to charge a battery bank or even create Grid Tied AC power (use utility like a "giant AC battery bank"). But I do not know any that are designed for use with electric heaters at this time.

-Bill