DIY Wood Stove Fan for Under $50

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So I bought an EcoFan for a friend and decided that it was a cool concept and built one from scratch. The fan gets its power from a peltier element that is used in reverse, i.e. it is generating electricity from the heat given off from the stove top.

This peltier cooler is used in cooling cpus to tabletop wine coolers. Usually electricity is used to generate the peltier effect and causes one side to cool while the other side heats up. More can be found on the wikipedia article on http://en.wikipedia.org/wiki/Thermoelectric_cooling


I always wanted to build a Stirling engine but the complexity was a little too much for me, but this project was easily doable as a weekend project!

Tools required:
Drill
Hacksaw
C-clamps (or vice grips)
File/Sandpaper
Soldering Iron

Materials required:
1x 120cm CPU Heatsink ($20 shipped internet)
1x Peltier ($30 shipped ebay)
1x 1.5V Radio Shack hobby motor ($3)
1x Pentium II heatsink (salvaged)
1x 6" propeller (from my RC planes)
1x scrap 1/8" aluminium plate
6x nuts and bolts

It's relatively easy to build. I just sourced the cheapest and largest heatsink on the internet, which came to this 120cm massive heatsink for $20 shipped. It included all the right mounting plates that just worked. It had a mounting plate that was wide, came with a whole bunch of screws to mount it too. WIthout this it would have made it a whole lot harder to mount.

The $30 thermoelectric generator was sourced from ebay through a local vendor (because I was impatient and wanted to build it by the weekend). I also bought the high temp version, which raised the price considerably (which I have found isn't quite necessary as the module never gets that hot enough). So, if you're more patient, these can be sourced through ebay from chinese vendors for under $15.

The electric generated from the module is roughly about 1.5-3v. Not a whole lot of power, so Radio Shack to the rescue! Got a hobby motor for $3. And using a salvaged propeller from one of my rc aeroplanes, I managed to push fit it into the Radio Shack motor.

The base plate is a 1/8" aluminium plate I found and I used a hacksaw to cut out the pieces, then file away the edges.

There's no plans for it because it's basically lining up the holes, clamp it down, drill the holes out (although it helped that I had a Bridgeport mill, I could have just easily used a hand drill). Also I wanted to make it in such a way you can have a margin of error. I suppose you could also tap the holes and bolt it right on, but I wanted to keep it simple to build.

I made a little base and riser for the motor so it sits more centrally on the top heatsink and just ziptied it up.

The fan base heatsink is a Pentium II heatsink that I had laying around. The heatsink also does two things, one is that it raises up the height, and second is to reduce the temperature getting to the peltier module (because I wasn't sure how well it could dissipate the heat)

After the first run, I could touch the top of the heatsink and only felt that it was slightly warm. This fan works better than the EcoFan in the fact that it dissipates the heat better and can be put up front on the stove without losing too much efficiency.

All in all, about a couple hours of work!

So have fun building your own!

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33 Discussions

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floydian

2 years ago

I built one of these with two Perrier heat systems and they no longer work. I think I keep burning them out. Here are pictures. What am I doing wrong?

16, 10:00 AM.jpg16, 10:00 AM.jpg16, 10:00 AM.jpg
3 replies
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Xonk61floydian

Reply 1 year ago

I would suspect that if you were drawing more air through the plates of the heat sink, you'd be cooling that side of your Peltier more quickly, thus reducing the chances of damaging your Peltier. Repositioning the fan so that it cools more of the fins, or putting a shroud around it so that it draws primarily through the spaces between the fins may help.

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jeffr192Xonk61

Reply 11 months ago

The shroud is a great idea!

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jeffr192floydian

Reply 11 months ago

Nicely done on the motor mount!

I think your fan needs to be more in the middle of the heatsink, as it is, likely drawing most of its air from above the heatsink, where there is less resistance. Then, not much air is travelling over your fins.

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thompa08

2 years ago

Hello, I'm trying to make one myself, however the height can't be over 10 cm. What I use as cold side is one cpu-heatsink, the warm side is one "Aluminum Alloy Heat Sink For Solid State Relay SSR Heat Dissipation". With one tec1 pelltier element. My question is why it doesn't run a 12v fan?

4 replies
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WildOne1985thompa08

Reply 2 years ago

Simply because you can't get that much power (voltage) out of the module unless you have a lot of TEC/TEG modules wired in series.

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thompa08WildOne1985

Reply 2 years ago

Hi,
I have read your input on my problems. Would it work if I do as he does, use a ac electric motor? If it does, do you know where I can find a propeller that can fit in a space with over all height of 10 cm? ....with suitble material for wood stowes?
Thanks for the help.

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WildOne1985thompa08

Reply 2 years ago

What you have to do is to get a faster spinning motor with a smaller propeller + you will have to live with a little noise from the device because of it's speed. The speed will make up for some of the downsides of a smaller propeller when it comes to the amount of air moved.

I have a similar problem if I were to build one, but I would have bought two small motors, two propellers and two TEG modules.

Examples:

http://www.ebay.com/itm/201229071773?ssPageName=ST...
http://www.ebay.com/itm/391100073661?ssPageName=ST...
http://www.ebay.com/itm/131668463520?ssPageName=ST...

That is what I would have tried for my first attempt, but there are probably better options.

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dohebert

1 year ago

Awesome project! I too wanted to build a sterling engine but somehow have never quite gotten around to it. I already had the base heat sink for that project sitting around, so now I just ordered the top heat sink, motor, and peltier chip. Somewhere around the shop I have a little fan blade I was saving for the sterling project that I can probably attach to the motor shaft; if not I'll just buy an RC plane prop or make something out of a beer can. Looking forward to building this and maybe adding some steampunk decoration. As a bonus, while I was ordering parts I googled 'ecofan' just to see the fan blades they use, and amazon was offering a flash deal on a similar type fan by a different maker for $25, so I grabbed that too. Maybe I'll give the amazon fan to my mom for Christmas after I build my own. I like the idea of making my own so I know exactly how it all works and what to replace when the motor or peltier goes bad.

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malakesher

5 years ago on Introduction

This looks really cool. I'm not totally sure what it is for though. I have never heard of a stove fan before, is it to blow hot air around? Either way I want one hahaha

1 reply
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Starlytemalakesher

Reply 1 year ago

Sends the heat which rises off the stove out towards you, and round the room, or which ever direction you point the fan, instead of going up to heat the ceiling first before getting down to heat you, comfy in your chair in front of your stove. They're used a lot by people who heat just by wood stoves.

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zacker

4 years ago on Introduction

cant one use two or three pelletiers wired in series to get more power to a bigger motor? or does it really not matter how much air is displaced?

1 reply
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Starlytezacker

Reply 1 year ago

The wiring is explain on Wiki, "Thermoelectric generator", which is a great help, and easy to understand, as well as with pictures. You can put a few together, as described there, and do lots of things with the power they produce, quite fascinating.

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Starlytecolin.bannon.12

Reply 1 year ago

It is. I have one on my computer, it's for the CPU, the processor. Ebay or any computer component sales, but watch out for the prices, as some are quite expensive! For this you don't need one that breaks the bank!

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borisr6

1 year ago

I have tried to build this , but as the stove gets hot it heats up my
cool side heatsink (dell) too ,thus there is no temp difference and I am
getting ca 1.2V max . I have used a small hobby motor which won't
operate at this voltage. The fan works perfectly if I place it on a
burner , where heat in more centered under the fan . But when placed on
the stove I guess I am losing the temp difference. Any recommendations
on this please?

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shadow2010echo

2 years ago

Pretty cool well done, I bet it gets lots of looks? Might give it a go one week end cheers.Steve.

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Jellyfivebellies

2 years ago

Stoves get quite hot, but most TEG/Peltier plates cannot take the high temperature. To buy one that uses high temperature solder etc so that it can take 250degC costs several tens of $. Ebay has Chinese ones claiming to take 150degC, but I have heard this is a lie, and that they break. Which ones are you using?

You might get away with only a lower temperature capable Peltier plate because you are standing it off the stove surface using the smaller Pentium heatsink; this is reducing the temperature on the hot side of the Peltier, but it also makes everything less efficient.