# Electric generator from chimney draft?



## flyingpig (Sep 9, 2011)

One common problem for the wood insert is that it won't spread out the heat that much during power outage and the fan stop working. But I guess that the electric power to turn the fan is not that much, and I've heard that the draft from chimney is pretty strong. So if we can put a small fan-generator on the chimney, we may be able to get over that problem during power outage.

Just wondering...anyone did this before? Or any advise on how strong is the actual draft from chimney? How will this impact the burning efficiency? My chimney is not that easy to climb so I don't have any way to verify it myself.

Cheers......Som


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## nate379 (Sep 9, 2011)

There is not enough draft on a chimney to spin a fan to any speed that would create power like that.  Might be able to power a calculator or clock but that's about it.


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## jharkin (Sep 9, 2011)

Agree 100% with Nate... If the draft was enough to spin that fan you would end up blocking the draft  


This has been discussed before,  one option proposed is to get a small deep cycle battery and inverter.  Don't try a computer UPS as they wont handle motor loads well.


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## btuser (Sep 9, 2011)

You could boil water and use the steam to push a turbine, but it would have to be a pretty hot fire to get 400-600 watts.  Even outdoor boilers use line voltage to run their fans.


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## flyingpig (Sep 9, 2011)

Thank you guys. Now I'm looking for a new project. NEXT !!

Cheers......Som


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## Corey (Sep 9, 2011)

The battery / inverter is probably the best bet.  I have a palm sized inverter, around 200 watts IIRC - runs my main blower fan fine off a car battery.  During an ice storm/ power outage, we heated for 3 days with only the inverter / battery combo (with daily re-charges on the battery).

Some have used the Freebreeze wood stove fans which run off heat (thermoelectric).  I believe there are also some stirling cycle fans out there which would do nicely running on stove heat as well.  I guess you could also go full blown antique and get and get a Lakebreeze fan which would run off a kerosene / alcohol lamp.  Then you have light, heat and breeze all at once....talk about combined cycle!


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## semipro (Sep 9, 2011)

If you were to try and use the draft for power generation it would be better to install the fan on the inlet to the insert rather than the flue for obvious reasons.  Trouble is you may not have a connection for an outside air kit on your insert.


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## Adios Pantalones (Sep 9, 2011)

People do use Stirling engine fans to move air- this is based on heat differential rather than air movement being used to generate 'tricity.  Maybe find a way to efficiently run a stirling in an insert?


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## flyingpig (Sep 9, 2011)

Thank you folks. Lots of good ideas here. I didn't think about getting 300~400w fan but may be something enough to get some air flow like the Eco Fan. Unfortunately, the Eco Fan itself doesn't have a place to stand on my flat-face insert (FX-33). Oh...and also I don't have the OAK for that too.

I may end up with the battery/converter route. But it's not that urgent now. Who know? Giving the fact that we have all the natural disasters we can think about here this year (Earth Quake, Hurricanes, Too many tornadoes,  Wild fire), I would feel surprise if we have an ice-storm hitting mid-Atlantic this winter.

Cheers......Som


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## fishingpol (Sep 9, 2011)

Here is a cool video showing a stirling engine on a woodstove.  Nice little stove.  The noise would get annoying.  There are some good basement mechanics out there experimenting with projects like this.

Stirlings can spin fast, but little torque to them.

http://www.youtube.com/watch?v=pPVCLpnTnvI


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