Using Wind to Heat Water IE:Dump Load

[adobejoe]

Have a 10 KW bergey here in NW Wyoming, so know something about windpower.  Anyhow, I use radiant in floor heating and included an electric conventional water heater along with propane flash heater (Takagi)to heat the water/glycol. I would like to buy or build a, say, 1 KW turbine and simply "dump" by connecting to the one (or two) resistive heating elements. The tank is standard 40 gallon. I realize I may need something like a xantrex C40 or C60 controller.  Has anyone done this?  Have found a few postings. Must I change out the resistive heating elements to DC specific, or can I use the originals?  New to this board.  Enjoy the postings! AdobeJoe

[nunyabeezwax]

Joe,

there are possibly 100 or more postings on water heating, if I were you I would:

http://www.fieldlines.com/special/google

I am +++positive+++ you will find plenty of good posting to read!

[harrie]

Hi, I guess I would suggest using a seperate water heater tank ahead of the one you have hooked to the grid. You can use 120 volt heater elements, but they will heat at a reduced rate, depending on what voltage you are feeding them at. I think using a controler, you will need to use a battery bank, and I would suggest a C60.

At 48 volts, a 120 volt 2000 watt heater element, will draw only 500 watts at 8.3 amps. At 24 volts, it would be 125 watts at 4.2 amps, and at 12 volts, it would draw 31 watts at 2.1 amps.

With my 48 volt system, using a morning star 60 amp controler, I built a tank with 7 120 volt 2000 watt elements. this many is needed to have the diversion load large enough to divert all the current produced by the wind . It is basicily the value of the battery voltage times the maximum source current.

You can of course use 48 volt elements, or 12 volt and also 24 volt. I think some on this board are heating water directly from the turbine, and not using a battery bank, so maybe they will give you some ideas, but I think you would want to keep the turbine current seperate from your other heating tanks for sure! hope this helps.

[adobejoe]

Harrie, Yes water heater will be disconnected from grid.  I would replace the two elements (upper and lower) with the low voltage DC type that apparently are thread compatible. STypically 25-50 Amp. Since I am using the wind turbine fully as a heat source, I want to just keep enough battery capacity to maintain a load to the turbine, I guess, with near all wind power going into the two water heater elements.  I think this should work, but am a little concerned with overheating. For example I do not imagine the existing water thermostats will still work, as they are AC?  How to protect from overheating...maybe not a problem...but we get a lot of wind at times in winter in Wyoming...Thanks for your comments. AdobeJoe

[snowcrow]

I'm from NE Vermont and know how hard it can be to stay warm and still try to stay green!!! I use a few hot water panels, and the wood stove with a heat exchanger for my radiant floor heating. You'd be amazed how little wood it takes to heat a lot of water!! These are my main sources for heating water and the Dump Load heating comes second. In the winter months I've found it best to hold on to every kwh I can!!!  Last February it stayed below zero for days and reached -54F one night, electric hot water heating just can't keep up with the volume of water to be reheated.

[Nando]

The Wind Mill water heater should have a high voltage output to maximize the generated powr into the load.

The optimum generator should have around 240 Volts AC at peak power generation.

Ideally the system should have a heater controller that has proportionality or MPPT (Maximum power Point Tracking) loading to attain maximum power harvesting.

This way the water heater loads can be the standard 220 volts resistive elements.

The controller should, as well, have an ELC function to protect the system from over speeding and this ELC could use the same water tank and heater elements, but the system should have in addition a resistive load in parallel with water heater if the water heater thermostat disconnect the tank due to high temperature.

Wind Mills with Pitch control is the best arrangement since they can operate producing maximum power under almost all wind conditions if properly designed.

The ideal Wind mill is the Torque Pitch controlled hub since it uses the load torque to maintain the setting to its peak power harvesting, a second best would be the centrifugally controlled Pitch hub.

Nando

[adobejoe]

Nando,

Appreciate your comments. Converting to AC will require an inverter.  More equipment equals more losses, electric and initial costs ($'s).  There are a number of DC water elements for H20 heaters out there, that enable me to use the same tank. Am trying to keep system DC from turbine to water. AdobeJoe

[vawtman]

Hi Adobejoe

 You can feed ac elements dc they dont care.

 My thoughts are to wind my stator 3 ph rectify and feed stock elements.But it would be designed for high voltage has Nando states.

[PHinker]

Does your turbine/generator generate DC?  I guess I didn't see what sort of turbine you're planning to use but if it's a self-built axial flux 3ph similar to the common ones described here, why rectify the output at all if you're looking at using AC?  I don't think resistive heating elements care much about frequency and if the mill is planned to be used solely for water heating, you could build the stator for high voltage and just skip the rectifier I would think.

[vawtman]

Hi Phinker

 The reason i mentioned rectifying was that he wanted to feed a stock water heater.You would need 3 elements to feed 3 ph ac.

 Mark

[adobejoe]

Phinker and others:

You have me really thinking now.  Starting from ground zero and have not choosen a turbine yet. Was thinking of a 1 KW bergey xL1 or southwest WP whisper, which are DC, but now thinking of making my own if I can save some dollars, and get the thing built easily.  Regarding the 3 PH Ac needing three elements, what about this option.  I actually have two conventional electric water heaters (one for domestic water, the other for radiant ssytem). Each has two elements. This might be a stretch, but if the 3PH AC is most efficient, how about using two elements from one wter heater and one from the other, to get the three?

I like the idea of not having batteries at all....comments?

AdobeJoe

[vawtman]

I would direct all the power to one element unless your going bigger than your origial thoughts.Then i would think you could use the high limit to short the turbine maybe.The other could be used when the winds are gone.

 Just thoughts

[adobejoe]

Nando's comments seem best:

Go with an AC alternator turbine, max output approx 240 V, use existing water heat elements, probably use three elements if possible. Use two elements from one heater (radiant heating) and another from my domestic water tank, with an additional resistive load IF all reach temperatures. I like the power of three: three turbine blades, three phase AC, three heating elements. NOw time to find the components.

Adobe Joe

[Nando]

It does not matter if the power is DC, AC, single phase, 3 phase or multiple phases.

The single resistive element may accept all of them if proper steps are taken.

If AC single or DC then direct to the element via the controller.

If more than one phase, rectified the multiple phases power then supply the DC to the resistive elements, via the controller.

Multiple phases, if independently loaded may need independent resistive loads with proper phase separation or loading.

The simplest controller would be one for DC which is just a proportional resistive insertion % to follow the available power. ( implies to rectify the AC ).

Ideally a MPPT is needed to harvest the variable peak power available.

Nando

[windstuffnow]

  Not to throw a stick in the spokes but a 1kw turbine will only act as a supliment to heating the water.  If it was running full out producing 1kw 24/7 that's only 81,600 BTU per day in heating.  That would take care of a portion of your domestic hot water and wouldn't do much for heating an area.   Obviously, it won't be running at maximum all the time so it would give you somewhat less on average.  Seems to me to be an expensive way to create heat.

  I'd like to say I have a better idea or way to do it but I certainly don't.  I like the creative thinking going on, it usually leads to ideas that could work and hopefully an idea will be spawned from the post.

  I've tried running from a turbine to an element - seems to need alot of input power... built a small eddy current heater and it seems to have promise but there again you need lots of input power.   I've calculated the needs of my home heating, trying to come up with alternatives, but I would need 5500 watts minimum continuous 24/7 in winter - that would take a darn good sized turbine in a 15mph average as well as a fairly large storage to offset the lower wind days.

  We really need a way to store the heat and cold of the seasons.  All summer long heat a storage tank for winter and all winter cool a tank for summer.  That would be an expensive up front cost but could last for generations of free heating and cooling.  And, yea, I've calculated the size of the tank needed ( for water storage anyway )... big... really big... about 30ft diameter by 80ft long.   If your fortunate to live by a lake you could plumb a few hundred feet of copper to the bottom of the lake and use the cool water and forgo the winter storage for cooling.  My ending thoughts on the storage were that if I was going to build and bury a tank that large I would simply insulate it, partition it off and move in.  It wouldn't take hardly anything to heat it and nothing to cool it.   What if???...

.

[electrondady1]

yea, but ed, he said it was 10kw.

[Nando]

let me give you some info.

sometimes back I presented a wind mill, 11 kw used for home heating by heating a large,I think, 2 cubic meters of water tank.

The house is about 350 + years old in England, it may have better "reduction" of heat escaping "holes".

Simon, the owner, said that he has plenty heat during the winter, the wind mill is in 8.5 m/s clear area.

It all depends what is needed and how is done.

Some apartments in Dallas, use the water heater ( 50 gallon, gas) to heat the apartment well - around 750 to 1200 square feet areas.

There is a how, in Plano, Texas that has two tanks in the basement, I think around 10,000+ gallon each, one for cooling and the other for heating, with a heat exchanger to extract/expel energy from/to the air during the different seasons since the tanks are used to keep the house air conditioned.

Nando

[windstuffnow]

 He said he had a 10kw in use, but wanted to build/buy a 1kw for heating water.  My calculations for the storage system are based on Michigan weather where the winters are sub zero.  I don't know what the summer/winter's are in Wyoming or Texas so the calculations would need to be adjusted accordingly.

.

[adobejoe]

Yeah, we do use the 10 KW which meets most of our electric needs, but we also use quite abit of propane for our radiant floor heat and cooking. Because of the way the utlity applies the net metering law, and I would like to try and reach "net zero," I am looking into a smaller turbine dedicated to heating....have the electric water heater already plumbed in to the radian in series with the propane. So looking into this.  A commercial 1 KW +/-, batteries, controller might run onthe order of $2,000, so I am looking at optins including having one fabricated.  We have very nice winds where I live, east of Yellowstone Park---You all heard of that place?  No ,I do not want some gargantuan tank under ground. Trying to keep this simple---AdobeJoe

[GaryGary]

Hi,

I am wondering why wind power to generate heat?

Wouldn't it be cheaper and simpler to just use solar thermal collectors?

Bergey says that their 1KW wind turbine generates 1KW in 25 mph, but gives a "nominal" power output per day of 5.2 KWH -- not sure what wind velocity that goes with.

It costs $2600 plus a tower adds another $1600 -- maybe $4200.

I live north of you in Bozeman, and built this 240 sqft of collector for $2200:

http://www.builditsolar.com/Projects/SpaceHeating/SolarShed/solarshed.htm

On a sunny day, this generates about:

Qsunny day = (240sf)(1600 BTU/sf-day)(0.6 efic) = 230,000 BTU or 67 KWH

If you figure half sunny days, maybe it averages more like 35KWH a day.

So, the solar collectors seem to generate about 7 times as much heat for half the price?

Home built solar air collectors are much cheaper yet.

Gary

[adobejoe]

Gary:

Nice installation and pics.  Your calc's look good, but there are some other things also to consider.

I already have a tower, and in fact my site, is such I can use a very short tower, like 10 or 20 ft.  My 10 KW generates 22 KWH daily, yearround, on a 55' tower. So, I think I can get 2-3 KWH daily, more in winter.

Secondly, I plan to use the turbine yearround; for the radiant system in the winter, and domestic hot water in summer, so I have I have 12 mo use. Your system is unavailable six months, right?

I do not have a conducive site for an installation like yours, and another issue, would be drifting snow covering the panels, which I note in your pics is apparently an problem in Bozeman. I have enough problem plwing out my driveway at times, not sure I want to clear panels.

having lived with windpower near 3 years, one of the things I enjoy very much is the virtually zero maintenance.

Thanks for your comments,

AdobeJoe

[GaryGary]

Hi Joe,

I have a separate system for solar water heating, but thats more a mater of poor planning than anything else

The same system could easily be used for both summer and winter water heating -- thats the way most people do it.  A system that is large enough to produce useful heat in the winter will produce all the hot water you can use and then some in the summer.

The snow on the panels is a once in a while thing after storms from the south.  It melts off by itself by midday. If I had it to do over again, I would place the panels vertically, which works out very well for space heating -- you get the benefit of the reflection off the snow, as well as no snow accumulation on the panels.

My shop heating system uses vertical panels:

http://www.builditsolar.com/Projects/SpaceHeating/solar_barn_project.htm

It never accumulates any snow on the panels.

I guess my main point was just that it seems a lot more cost effective for heating applications just to use the suns heat directly rather than turning the sun/wind energy into electricity and then back into heat?

If you get 3 KWH per day out of the new turbine, thats about 10,000 BTU/day -- equivalent to about 1/10th gallon of propane.  

If you spent the same amount of money on building a solar thermal system you might get about 35 KWH per day -- equivalent to 1.3 gallons of propane.

Just my 2 cents

Gary

[windy]

adobejoe

I replumbed my 80 gallon water heater so I could use three elements. This tank is used just to preheat the water before it goes into the primary water heater. I built a 3 hp 3ph motor conversion which is hooked directly to the three elements through a relay that switches the elements between star and delta. It works good but a 1 KW generator won't give you much hot water. I used 3-4500 watt 240volt 1 inch threaded elements. I inserted the top and bottom elements through 1 inch galvinized tees into the tank, and the other element is inserted in a vertical pipe that is connected between the top and bottom elements. When the water starts to get hot in the vertical pipe, it naturally circulates from bottom to top. No circulating pump is needed.

windy

[adobejoe]

I'm back...okay, thanks for all the great inputs.  Here is another angle to heat that water.  I have two Kyocerea 130 W panels sitting in the garage, doing nothing. Can I just hook them up in parallel and connect them at 12 V, about 22 Amp, to the lower water heater element?  I have seen all these specialty resistive heating elements rated at 12 V one can order, but why can't I just use the ones in the tank?  Maybe the efficiency is not as good.

Yeah, I know the optimum way to generate hot water is solar thermal but I do not want to mess with the plumbing.  I have an adobe house with 14" thick masonry walls, I do not want to make that kind of holes through my walls, but I have a wire chase (conduit) in which it will be very easy to run wire.  By the way some pics of the house , and wind turbine, can be seen at www.homes-across-america.org  Go to Wyoming and lookat "Adobe Acres."

Adobe Joe

[JDRYNNE]

Hi, very interesting, Nando. Is such a controller available? My alternator is a 3 phase high voltage, 200-400VAC open circuit, and I have a 230v 2.7kW 19ohm heating element in my water tank. I would love to directly connect the wind mill via this type of controller to the heating element. Where can I get one?

Many thanks, JD

Nando wrote:

The Wind Mill water heater should have a high voltage output to maximize the generated powr into the load.

The optimum generator should have around 240 Volts AC at peak power generation.

Ideally the system should have a heater controller that has proportionality or MPPT (Maximum power Point Tracking) loading to attain maximum power harvesting.

This way the water heater loads can be the standard 220 volts resistive elements.

The controller should, as well, have an ELC function to protect the system from over speeding and this ELC could use the same water tank and heater elements, but the system should have in addition a resistive load in parallel with water heater if the water heater thermostat disconnect the tank due to high temperature.

Wind Mills with Pitch control is the best arrangement since they can operate producing maximum power under almost all wind conditions if properly designed.

The ideal Wind mill is the Torque Pitch controlled hub since it uses the load torque to maintain the setting to its peak power harvesting, a second best would be the centrifugally controlled Pitch hub.

[ghurd]

I don't expect you will hear from Nando about any magic mystery control type stuff, let alone where you can get one.

http://www.fieldlines.com/story/2007/9/15/154035/292

[JDRYNNE]

ghurd, thanks for the warning, mate. Who needs time wasters!

Anyone else know of a wind turbine controller designed for connection to a water heating element?

My 2kW alternator outputs 200-400VAC. My water heating element is a in an immersion water heater 230v, 2.7kW, 19ohm copper resitor with a bimetal cutff on the element.

TIA, JDRynne