Heat Water With Wind

[Yianie123.]

I am also trying to heat water with wind.  I have in the past used, 4 - 24V - 500W, 5ft diameter wind turbines to heat a 24/48V heating element.  I have tried using a controller to measure voltage and divert to the heating elements when the turbines reach 12V, but yet the blades would then move in slow motion.   I know that the heating element is quite large, but I also wired just one of the element (2 elements per unit, and still nothing worth while.  I have even tried to use a battery as a buffer, still did not work.  Now I have decided to build a wind turbine.    I am willing change the entire design if someone can help me.  I have hydronic water heat for home heating so a larger heating element will be even better. 
John

[tecker]

 Post more info on the turbines It sounds to like your using a stator designed for Highspeed operation and incapable of the grid into a large constant load .

[Yianie123.]

Thank you for your reply.  The turbnie are 24V-500W PMA, approximatly 5 ft diam.  They are high rpm wind turbines purchased from Missourrie wind and solar http://www.missouriwindandsolar.com   I am using two (2) heating elements purchased from AltEstore.com
http://www.altestore.com/store/Charge-Controllers/Dump-Loads-Dump-Load-Controllers/Diversion-LoadsDump-Loads/Low-Voltage-Water-Heating-Element-2448V/p2327/

I have tried using a battery and using the heating element as a dump load, but what ever I do, the open voltage, which is about 30-40V at times, go to 4-5V when connected to just one of the elements.  Even half the element (2element per fitting).  I really need to make a lot of hot water.  Any suggestions will be greatly appreciated.

[ghurd]

The problem is a junk controller.

The dump load Must be connected to the battery.

Your controller is the type that disconnects the turbine from the battery, and connects the turbine directly to the load.
That is bad.

It is especially bad with that type of alternator. 
The alternators coil resistance is high.  The heating element resistance is low.
Most of the heat is being made in the alternator coils.

I suggest getting a normal controller, from a respected well known manufacturer (meaning there will not be any relays),
and connecting the system in the way shown in the owners manual.
It will require the use of a battery.

Could even do it with my little controller, a few extra mosfets, and a battery.

The system will make more hot water if you build the dual rotor type turbine common on this site.
Reworked car alternators are not so great.
G-

[piglet2]

Hi.

Try to connect both heating resistors in the elements in series and then both elements in series too.  All the resistors in series.
Might help IF the mill generates enough power, but very little.

/Piglet

[ghurd]

Try to connect both heating resistors in the elements in series and then both elements in series too.  All the resistors in series.
Might help IF the mill generates enough power, but very little.

The 1st problem with that is the turbine will be basically shorted in low wind.

2nd is, if a controller is used, strong winds will over voltage the controller and let the smoke out.
All 4 elements in series is 5 ohms.  The electronics will probably be smoking at about 8A

A battery and decent controller solves those problems.
All 4 elements will have to be connected in parallel (2530W) to make it safe for four 500W turbines (2000W).
G-

[piglet2]

Sorry, ofcourse.  I was thinking of just one of those mills, a temporay fix and manually connected resistors.
Naturally the only really working alternative is a battery and a real controller.

By the way, is it possible to find from somewhere a controller (diy or commercial or schematics) for waterheating with a 300V 2kW turbine, no batteries, no mechanical relays?

/piglet

[Yianie123.]

Thank you for your replies.  So, if I do use a controller to divert access amount of current to the heating element and at the same time a relay that will also connect the heating element it would be ok?  If so is there any problems back-feeding the diverted load from the battery throught the element and back through the diverted load to the controller?  Also, should I be expecting that the batteries will cylcle betwean charging and discharging when connected to the heating elelent?  And what condition can a PMA overheat?

[Yianie123.]

Thank you for your replies.  So, if I do use a controller to divert access amount of current to the heating element and at the same time a relay that will also connect the heating element directly to the battery, will it would be ok?  If so is there any problems back-feeding the diverted load from the battery throught the element and back through the diverted load to the controller?  Also, should I be expecting that the batteries will cylcle betwean charging and discharging when connected to the heating elelent?  And what condition can a PMA overheat?

[willib]

Yianie123 , what is the resistance of the heating elements?
using V/R will tell you the current the elements will draw from your batteries.
if your battery voltage is 24V and your element is 2.48 ohms the current it will draw from the battery will be 9.68 Amps.

[Yianie123.]

Each of the elements (2 per unit), has a resistance of 1.8 ohms. 

[ghurd]

This is why I do not like the term "Diversion".  Or "Shunt".

You have a serious misunderstanding about how a Decent dump load controller operates.
It dumps power from the battery.
The windmill keeps charging the battery.

A decent dump load controller does NOT change the windmill amps from going to the battery, to going to a dump load.
A decent dump load controller sends amps from the battery to the dump load.
A decent dump load controller does NOT 'divert'.

"So, if I do use a controller to divert access amount of current to the heating element and at the same time a relay that will also connect the heating element directly to the battery, will it would be ok?"
There is no reason to have a relay, or an extra relay.

A shorted or semi-shorted condition can make the alternator burn out.
Heat in Watts = Amps x Amps x Ohms.

Example-
With 10A flowing...
Heat in the 0.45 ohm heating elements = 10A x 10A x 0.45 ohms = 45W in the heating elements.
Guessing the stator has maybe 5 or 10 ohms of coil resistance?
With 5 ohms of coil resistance,  Heat in the stator = 10A x 10A x 5 ohms = 500W in the coils.
With 10 ohms of coil resistance,  Heat in the stator = 10A x 10A x 10 ohms = 1000W in the coils.
The heat is being made, it is just not being made in the right place.

Piglet,
Zubbly made a 3-ph direct heating system with no battery or controller.  It used caps in series with the heating elements.
I believe DaveB did something similar.
It is not very simple to get sorted out and efficiently functioning.

G-

[tecker]

It sounds lake a parallel connection battery and heating slement.

[Yianie123.]

Thanks for the info ghurd.  I believe I understnad what you are saying.  The reason I would use a relay is because I am using a name brand controller that is limited to 40 amps.  If 4-500W-24V turbines are maxing out, will I not exceed 40 amps?

Also, I do I avoid burning up the stator in your example?

[Yianie123.]

Do I only need to worry about the stator in a shorted or semi-shorted condition?

[ghurd]

It is hard to guess this stuff.

So far, in 14 posts, everything we know is-
you have 4 500W turbines purchased from a company that does not sell 500W turbines,
and where you purchased the heating elements but not which one (they do not sell one with 1.8 ohms),
and an unspecified controller from an unspecified company you consider a name brand.


What Brand and Model is the controller?


MorningStar operates at 300 to 360 times per second.
Xantrex operates at 160 times per second.
A relay running 160 or 360 times per second will sound like a buzzer until it fails.

The battery supplies the amps to the dump load.
The chart at the store link shows how many amps the load will use.

2000W of 24V wind turbine is about 70A going into the battery.
The combined dump loads will pull up to 60A or 90A maximum, depending on which type you have.
The dump loads are marginally large enough.

The 40A controller is not large enough to carry 60A or 90A from the battery to the load.

When properly connected, to a battery, the stator should be safe.

[Yianie123.]

The company Missourri wind and solar, did sell 500W-24V turbines.  They have recently changed there magnets so their rating is higher.  The morningstar tristar I am not using as a load controller, so when the batteries are charged, a relay will be energiezed to connect the heating elements to the batteries.  The heating element 1 of the pairs of two, was measured with an ohm meeter to 1.8 ohms.  Now that we have that cleared up, does anyone know if there are any conditions other than short that will burn up a pma?

[Flux]

I have only just seen this.

Let's think about this realistically. 5ft turbines will probably average under 100W in normal winds, you will need an absolute gale to see 500W if it is even possible.

You say your heaters are 1.8 ohms so at 24v you have each heater taking a bit over 1kW. Only in a real gale could all four turbines hope to power one heater so you are effectively shorting the turbines out and they will stop and just crawl round.

For heating you really need a controller that applies load to suit the wind speed so the turbine doesn't stall. if you use the battery you will need to charge it and dump it to the heaters for a short time until the volts falls then charge it up again.

With your little turbines you may dump full load to those heaters for a few seconds every few hours. With a proper load control you may be able to average something up to 200W into the heaters in normal winds and probably most of the time it will be less. if you find this amount of heat useful you will have reached your goal but realistically tiny turbines are never going to give useful heat except during a gale.

Just don't use all the heaters so that the current draw is below 40A and you can use your controller as a dump controller and you will get all the heat you can produce as long as there is no other load on the battery. This is the best you can do.

Flux

[Yianie123.]

Thank you Flux for your help.  There was a mis-type in my last posting.  My plan is to sell the turbines that I have, built an 8ft dia. turbine to charge batteries.  I have the Tri-star 40, load controller, so that when the batteries are charged a relay will close, allowing the batteries to discharge to the heating elements.  In a wind storm, my turbine will still feed the batteries while the batteries are still feeting the heating elements.  I believe if I have batteries betwean the heating elements and the turbine, there will not be a chance of burning up the generator.  Do you agree?

[Flux]

If you charge a battery and use a charge controller to divert to a heater your turbine should be ok. It will only see the battery that it is intended to work with.

With an 8ft machine at 24v you will seldom see much over 40A. As long as you choose your heaters not to exceed 40A the charge controller will drive the heater direct in pwm mode. This is probably better than using a much bigger heater and dumping via a relay but that will work if you particularly want to go that way. Again it will not affect the turbine which should be permanently connected to the battery.


If you do use a relay try to choose a differential on the controller to keep the relay from switching rapidly but don't go too far or you will be cycling the battery outside the surface charge region.

With an 8ft machine in a good wind area you may get some useful heat on windy days but don't expect too much. For heating duty you need something above 12ft to get any serious amount of heat.

Flux

[Yianie123.]

Flux, thank you again for the info.  Do you know where I can find 12ft dia. plans for a wind turbine or any size slightly bigger or smaller will be greatly appreciated?

[piglet2]

Hi!

I found this, might help:  http://exmork.itrademarket.com/1417806/wind-powered-water-heater.htm

/piglet

[wooferhound]

Why don't you want to use Solar Thermal Water Heating ?

[Tritium]

Flux, thank you again for the info.  Do you know where I can find 12ft dia. plans for a wind turbine or any size slightly bigger or smaller will be greatly appreciated?

Hugh Piggott's Newest Book has a 12 footer.

Thurmond

[Dave B]

I don't want to discourage your attempts to heat water with the wind but the bottom line is that you do not have enough swept area or proper alternators designed to produce the kind of power needed to heat water a useful amount in a reasonable amount of time. A 5' diameter machine might possibly be able to produce 500 watts in a 30+ mph wind or better. You might get 60 watts charging a battery in a 15 mph wind. Resistive heating is a different game, IF you had a constant 15 mph wind and IF your blades and load are matched for this speed you could possibly raise the temperature of 50 gallons of water 1 degree F. in a bit over 2 hours. Sorry but it's physics, I have been down that road and made this work reasonably well with my 16' machine and a lot of tweaking. Anything less than 1000 watts in a 15 MPH wind will require a lot of time and very good insulation to heat a useful amount of water to a considered hot water temperature. A large pre-heat tank inside and before your main hot water tank is a good start to dump your power to. Anything helps but no matter how you crunch the numbers you can only get so much power from a 5' diameter chunk of wind.  Dave B.

[Yianie123.]

Thank you all for your help.  I greatly appreciate all of your comments, good and not so good, all are extreamly valued.  If anyone has an additonal comments, please place them on the site, John

[ghurd]

Like Flux and Dave said, there is just not all that much power available as far as heating water is concerned.

A semi low wind day may only raise the temperature a couple degrees, which will basically be lost through the tank insulation as fast as it is being made.

On a good note, a pre-heater tank will absorb heat into the water.
If the water is coming in at 11.6C (53F), in summer, when the ambient temperature is 24C (75F), then the water temperature will increase by simply being in the pre-heater tank, which will save a lot of heating power.

If the pre-heater is an electric hot water heater, then the elements can be replaced with DC heating elements to suit the voltage, power, and the rest of the system.

And the MorningStar you have will work, as long as you add a battery, and watch out not to over amp the controller(s).

It is the basic dump load pre heater.
G-

Edit- 24V to 24C

[ChrisOlson]

The company Missourri wind and solar, did sell 500W-24V turbines.

You are talking about those turbines that drive modified GM 10SI alternators and have a bouquet of 2-1/2 foot blades that look like some sort of alien flower?  A piece of advice on those - if the turbine itself survives the tornado you might get 500 watts out of it but whatever you were powering with it will probably be gone.
--
Chris