# Self Sufficiency/Living off the Land or Off the Grid > General Homesteading >  HOW....????? Does a "Ecofan" work....?

## Sourdough

http://www.caframo.com/hearth/hearth...cofangs806.php 

Everyone here has one, and many people have two. The house I stayed in last winter had one. So I borrowed one to see for it would work on my woodstove given that I run it at low temperatures. 

Well so far it is working perfectly. I moved my stack temperature gage off the stack and next too the fan and it starts at 150* degrees just like they claim.

http://www.ecofan.co.uk/woodstove-ecofans.html

But what makes it work........? Yes, just the heat. But why....? And I wonder could they make one large enough that it would circulate water in heat systems.

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## Rick

It uses a thermocoupler. Cowboysurvival posted on a stove that uses the same design. There's a link in it that shows how it works. 

http://www.wilderness-survival.net/f...ve+electricity

If you don't want to look at the thread. Here's the link. 

http://www.whcooke.com/thermocouple_guide.htm

Here's a diagram of one. 

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## ravenscar

Could you convert one to produce electricity?

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## Rick

Uh, it does produce electricity. I guess I don't understand your question.

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## ravenscar

what i should have said was " how hard is it to dissasemble and tinker with."

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## Rick

Personally, I don't know. I've never tried to tear one apart. If you are wanting to use it for a larger scale application I don't think it would be cost effective unless you installed it in something like a furnace heat chamber. The amount of energy required on the input side is pretty high compared with the amount of output you'd get. Solar or wind would be a much better choice IMHO.

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## ravenscar

i was thinking campfire chargers for some electronics

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## Rick

I don't know. You can pick up thermocouples at just about any hardware or plumbing store so you could try it. The tube in a gas appliance pilot light is a thermocouple. The flame in the pilot light heats the TC and creates current flow signaling the pilot light is on. I have no idea what the current output is, however. I would think your big concern would be something to protect the device from overcharging.

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## ravenscar

i was thinking to have the setup go to an outlet, then plug the chargers in. im no electrition so idk.

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## Rick

You'll never get that kind of voltage and, again I've never tested one, the output should be DC.

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## ravenscar

i will do some research. ac/dc converters can be made with a breadbasket i think, but i dont remember how

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## Rick

I think maybe they were just larger than a breadbasket but I could be wrong on that.

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## ravenscar

http://www.powerchips.gi/ i have no idea how to order if its avalible, im still surfing the site

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## hunter63

Thermocouples are generally used as a measuring device, out put in mV DC.
Output on a thermocouple from a furnace/water heater/boiler, using a gas valve, uses the pilot flame to generate 30-50 mV dc enough to "prove a flame" and keep pilot flame value open, thus the pilot flame burning.
If the isn't any mV output the value won't open. Safety deal.

A "power pile" (sorta like a bunch of thermocouples together) ups the anty to some where from 80 to 250 mV+, used on larger units, older units and stuff like deep fryers.
Used in the same way, mostly.

There is a tester I use to check out put of thermocouples when servicing heating units.

http://en.wikipedia.org/wiki/Thermocouple

I'm sure someone has thought of the power generating properties of heating/cooling dis-similar metals, I think you give away too much energy just to produce millivolts of electricity, (example: gas flame to produce 30mV).

I would be interested to see if that is really what runs the fan, or if it's natural convection on dis-similar metals, being heated and cooled as it rotates.

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## Winnie

Perhaps I'm having one of those dolly moments again but could you not attach a dynamo? The thing rotates doesn't it? Couldn't you replace the blades with a small PTO.

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## Sourdough

I just wanted to post that I did in-fact buy two of the "Ecofans" the three bladed ones. And they make a world of difference, the way they push the heat around the cabin.

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## hunter63

> Perhaps I'm having one of those dolly moments again but could you not attach a dynamo? The thing rotates doesn't it? Couldn't you replace the blades with a small PTO.


It's a matter of energy in vs energy out, energy can't be created or destroyed, just changes form.

Example, sunlight(energy) to wood growth (convert energy), cut wood( you use energy from food), burn wood, (energy given off as heat) ash, (returns to the system as fertilizer/food for microorganisms.

There would be too much friction and mass to allow rotation with my miniscule amount of power out-putted.

Think about the old wind mill in the yard, turning any kind of generating mechanism.
Then try to turn an alternator or auto generator by hand.............

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## Rick

Winnie - I don't think you produce enough energy to turn any kind of generator. I'd bet SD could stop the fan with a finger. 

Hunter - I wouldn't be surprised if all three properties weren't in use under the guise of a thermocouple. 

SD - If it works for you then it works for .... well, you know.

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## ravenscar

ok, so thats busted.......tea kettle steam engiene?

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## ClayPick

> I just wanted to post that I did in-fact buy two of the "Ecofans" the three bladed ones. And they make a world of difference, the way they push the heat around the cabin.


Theyre common around here. The efficiency thing for a wood stove is tenfold when you dont use electricity. Good stuff.

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## Winnie

Like I said..... dolly

Anyway, I may check out one of these myself.

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## ravenscar

i dont have a woodstove, im still using propane......but not at the moment.  all the gas leaked out and im colder than a witches (censored) in butte montana.
it may be nice once i start making things, blow some eccess heat awa from the forge when completed to warm a house

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## canid

a lot of fans like that have been made with stirling engines. pretty cook novelties, and some are actually usefull.

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## finallyME

> a lot of fans like that have been made with stirling engines. pretty cook novelties, and some are actually usefull.


A sterling engine would be much better than a thermocouple for power generation.  A thermocouple generates very little power.  But, they are great at temperature measurement.  Much better than an infared thermometer.  I made a thermocouple when I was in college.  Very easy.  If you look at the Omega website, they have specific information for thermocouple design.

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