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View Full Version : OT, How does this fan work? Any ideas?



fastfire
12-22-2016, 07:53 PM
http://www.tractorsupply.com/tsc/product/ecofan-ultrair-black?cm_vc=IOPDP2OWOW

It states that it starts turning at 212 deg. wondering if I could make one...

A.K. Boomer
12-22-2016, 08:24 PM
Don't know - not a sterling engine because they specifically state it produces it's own electricity so if it was sterling you would just go direct drive,,, thermocouple type technology?

The Doctor
12-22-2016, 08:25 PM
It mentions electric, so I'd say a thermoelectric module of some sort and a small motor. Bet it don't move much air.

A.K. Boomer
12-22-2016, 08:26 PM
Wait a minute - look at the temp specs at when it starts producing power --- 212F ring a bell?

fill it half with water and off you go with steam???

alanganes
12-22-2016, 08:32 PM
It's a thermoelectric module. Similar to the thermoelectric coolers used to cool computer cpu's but run in reverse. Heat difference between the stove side ant that heatsink thing on the top generates a voltage the runs the fan.


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A.K. Boomer
12-22-2016, 08:43 PM
yup thermocouple - two different metals that create electricity with temperature variance.

I thought that originally but then those starting temp specs made me second guess it yet if they were creating pressure why go electric instead of just direct drive so did not make sense.

but come to think of it - steam power would be ideal as it would add humidity into the house while heating...

two tiny jets at the props ends would get the job done no real moving parts but the fan ahhhh but the noise thing - damn... lol

John Stevenson
12-22-2016, 08:48 PM
Thermocouple.

These have been kicking about here for quite a few years, quite effective.

Bmyers
12-22-2016, 08:53 PM
http://www.ecofan.ie/?page_id=13

fjk
12-22-2016, 08:58 PM
I have one
They work really well when put on something like a wood burning stove

Sandwiched between the top fins and the body where the fan and motor are is a peltier device. Like a thermocouple, it generates a voltage across a temperature difference but I think (am not sure) that the physics are somewhat different. As someone said, they are Also used as CPU coolers.

Frank

PStechPaul
12-22-2016, 09:01 PM
I have some thermoelectric modules that I was going to use on my woodstove. I think they are 100 watts at 12 VDC. I used one to repair a B&D solid state refrigerator a while ago. I haven't tried them in reverse mode, but they should work pretty well on the woodstove. It is important to maintain as high a differential temperature as possible, so the fan should blow cold air from the room over the cold plate, while the hot plate should have good contact with the stove surface. It might even be helpful to rig up a small hydronic system with a small pump and heat exchanger coils, perhaps scrounged from a scrapped high end gaming computer.

boslab
12-22-2016, 09:48 PM
As said a thermocouple, hot junction cold junction array ,version I read about was a peltier cooler type according to the write up, there were a few DIY jobs on YouTube
Mark

J Tiers
12-22-2016, 09:58 PM
Those common Peltier devices DO have a max temperature. I forget what it is, but I think it is relatively low. Woodstoves can get VERY hot on top.

They mention 650 deg, but obviously the thermal path is high enough thermal resistance that it will not be close to 650 up where the works are. The motor surely cannot tolerate close to 650, and it is in between.

sasquatch
12-23-2016, 10:56 AM
Up in my area , there are lots of these fans. Many burn wood here for heat, and yes they do move air around.

EVguru
12-23-2016, 11:01 AM
Technically it's not a Peltier device, but a Seebeck device when producing an electrical output from a temperature differential.

A.K. Boomer
12-23-2016, 11:11 AM
Up in my area , there are lots of these fans. Many burn wood here for heat, and yes they do move air around.

I think Ideally this would be best utilized on double wall wood stoves like the one I have - mind has to run a blower, always a concern for if there's a power outage - stove will still keep the pipes from freezing but the inner box might overheat too.

if a device like this was built into the stove it would be ideal because you would have the best of both words to power it - a hot inner box and just a few inches away a cool outer - plus vast amounts of surface area to play with and make all kinds of gains, make them so they can be unbolted and serviced or replaced - - high temp silicone wiring runs down to the front of the stove to power the fans intake systems so motors don't overheat... what's not to luv? maybe the price tag some but now you have a truly great working concept...

J Tiers
12-23-2016, 11:49 AM
I think Ideally this would be best utilized on double wall wood stoves like the one I have - mind has to run a blower, always a concern for if there's a power outage - stove will still keep the pipes from freezing but the inner box might overheat too.

if a device like this was built into the stove it would be ideal because you would have the best of both words to power it - a hot inner box and just a few inches away a cool outer - plus vast amounts of surface area to play with and make all kinds of gains, make them so they can be unbolted and serviced or replaced - - high temp silicone wiring runs down to the front of the stove to power the fans intake systems so motors don't overheat... what's not to luv? maybe the price tag some but now you have a truly great working concept...

Can't be done......:rolleyes:

EVERYONE MUST BE fully and totally DEPENDENT on electricity in order to to live in their houses. Didn't you get the memo on that? It's a LAW.

You can have a wood stove, but if it works without outside electricity, it is ILLEGAL.

Baz
12-23-2016, 12:22 PM
While fun I think these are anything but ecological. The energy used in their manufacture is vastly more than they will produce so a mains powered fan would be far superior. They also only last a few years. A home made stirling would probably last longer and fulfil your desire to make things while producing something useful.

Cuttings
12-23-2016, 01:46 PM
We have one on a gas fired heater in our living room. It works very well. Doesn't look like it would move much air but once it gets going you can tell by how much more the rest of the house gets warm.
One thing to keep in mind, there are two different models one for gas and one for wood fired heaters. Apparently the wood fired heaters are much hotter and will burn out the thermal cell in a gas fired model.
If you use the gas model on a wood stove it isn't going to turn very fast. The great thing about these fans is that they still work when the power goes out.

wierdscience
12-23-2016, 02:03 PM
I like Myfordboy's version better:cool:-

https://www.youtube.com/watch?v=XzE7pkIknmQ

fjk
12-23-2016, 04:48 PM
While fun I think these are anything but ecological. The energy used in their manufacture is vastly more than they will produce so a mains powered fan would be far superior. They also only last a few years. A home made stirling would probably last longer and fulfil your desire to make things while producing something useful.

Yes you're right, but it assumes you have mains to connect to :-)

We don't use ours for greenishness- it's at a weekend/vacation cottage that's off grid. Having the fan helps keep it warmer. We do have PV and lots of batteries but a) we try to keep the load light in general and b) we run the wood stove in cooler weather, when the batteries are not quite as powerful and there is less sun to charge them.

But we digress.
But a stirling powered fan .... hmmmmmm :-)

Frank

fixerup
12-23-2016, 04:51 PM
I was given a non working one and took it apart to trouble shoot it. Tested the peltier device with a candle light and it produce some electrical power. Remove the motor from the large heat sink clamp, and connected a small variable power supply, but no sign of life. Took the crimped motor housing apart and notice some major corrosion on the very fine finger brushes,carefully clean them with a soda blaster. Greased the shaft and re-assembled it back together with fresh heat conductive paste on the peltier, re crimp the motor housing together. Aimed the small propane torch at the base and it soon started to turn. Wow! such a simple set-up and it works really well for that application.
The hardest part of this repair was to un crimp thick wall motor housing, To un-crimp that lip,I used a very pointed fine thread wood screw and wedge it between the two parts to open it up.
Cheers!
Phil

A.K. Boomer
12-23-2016, 05:17 PM
Good Job Phil, sounds like about the only thing that will shut you down is that triple propeller radioactive symbol and im the same way but when I see that thing it's time to throw in the towel no exceptions...

Black Forest
12-24-2016, 05:05 AM
I made a steam powered fan for a smoker once. It was quite complicated and I was always a little worried it would blow up! The fan moved the air around in the smoker giving more even temperature inside the cook box. If somehow one of these fans could be made to work or a sterling type fan then every Redneck in the world with a smoker would buy one.

A simple fan you could sit inside the cook box on the end of the grate to circulate the air/smoke would be a big thing in the smoker scene.

Baz
12-24-2016, 12:45 PM
you need a 'smoke jack' for that

Alistair Hosie
12-24-2016, 03:46 PM
Whilst watching a nice Indian movie I think it might have been The jewel in the crown. I saw something which equally fascinated me.it was a beautiful old cooling fan on a base on top of some ones desk .It seemed to be driven with a paraffin/kerosene/USA small driven motor quite how I could not see . I would love to own one. Sorry to intrude on your wonderful thread I just felt this might be interesting also to someone here Alistair. Wow youtube has a lot of them to see see here

https://www.youtube.com/watch?v=9M-8qtIVHFg

A.K. Boomer
12-24-2016, 04:05 PM
Alistair it's a sterling engine, when I went and visited the late great Jerry Howell to check out his mills before I bought mine he had one of those sitting on his desk pumping away with only a little candle flame under it.

I could not believe the amount of air it was moving - really was a piece of precision mechanical art,

he showed me a ton of stuff he built, what a great guy and a master builder for sure...