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Thermoelectric Fan Powered by a Candle

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video Thermoelectric Fan Powered by a Candle
A Thermoelectric generator powered by a tealight. It started as an experiment of how much power I could get from one candle. But I liked the idea and it worked really well so I built this electric-mechanical ornament. I did not use a high temperature TEG-module, but instead a cheap TEC-module. That can still handle 200 degrees Celsius which is good enough.

Please see my other project with a more powerful TEG:
http://www.instructables.com/id/Battery-Charger-Powered-by-Fire/

Concept:
It is also called a peltier element and when you use it as a generator it's called seebeck effect. You have one hot side and one cold. The module generates power to drive a motor and the motor fan/air flow will cool the upper heat sink. Higher temperature difference => increased output power  => increased motor RPM => increased air flow => increased temperature difference and so on. The airflow will spread the heat into your room, which is the purpose of this construction.
http://en.wikipedia.org/wiki/Thermoelectric_effect

If you unmounts the basement you could also use it as a stove-fan or move air from other heat sources. The motor start to turn at about 15 degrees difference, which to my surprise worked when I just went outdoors with it and the upper heat sink got cooler than the basement. You can place it in hot water, on an ice cube, a pizza and it works just as fine.

Total cost was about 50€ (incl. shipping costs). I used some spare parts but I bought most of it.

Components used:
• CPU-cooler (cold side): Zalman CNPS5X (Base plate: 33x33mm)
• CPU-cooler (hot side): From an old PC (WxLxH=78x63x67mm)
• TEC-module: TEC1-07110T200 (30x30x3.3mm)
• DC Motor: 1,5-3V
• USB-fan (metal, only needed the fan)
• Thermal paste: Arctic MX-4
• A piece of wood
• Two pull springs
• Four M4 bolts and two M3 bolts
• Aluminum tubes (optional)

TEC specification (at ΔT=68C):
Vmax: 8.5
Imax: 10
Qmax: 52.7
Tmax: 200 degrees Celsius
Source: http://www.termo-gen.com

Construction:
First of all, it does not need to be exactly those components. Other heat sinks, TEC/TEG, motor, fan, thermal paste, bolts and base plate can be used. Main concept rules are:
  • A TEC or TEG module (smaller dimension than upper heat sink base plate). Specifications are not that important but make sure it can handle high temperature. Many modules are only 100 degrees C and then you need to modify the construction as it gets warmer than that.
  • One hot side that is not hotter than TEC max-temp (My candle flame never touches the surface)
  • One cold side, an efficient heat sink (heat pipes) are a good choice
  • Good thermal paste to maximize temperature difference
  • Low voltage motor, around 1V. I prefer it to be quite (low dB)
  • Fan with high air flow at low RPM
  • Base plate that adds stability, holder for light, isolate heat
  •  
The lower heat sink (hot side) was cut and polished to get it nice looking. I kept 5mm of the fins to absorb the heat well when the light flame burns and increases distance to the surface. New dimensions are 78x63x15mm. 4 holes are drilled through the heat sink and threaded as M4. 4 bolts will hold the lower heat sink on top of a wooden platform. Bolts go through the platform from below, covered with aluminum pipes for a better looking design and are screwed into the heat sink. The distance between wood and heat sink is 35mm but I would make it 40-45mm as the flame almost touches the surface. You don´t want that because it creates black soot. The lower heat sink gets really warm but at the same time it works as a cooler to not get TOO warm, that would melt the TEG-module.

Two springs attached to M3 bolts fixate the upper heat sink on the lower, with TEC-module and thermal paste in between. Both surfaces of the TEC are covered with a thin smooth layer of thermal paste. The springs adds pressure as well as isolate the heat to travel to the cold side. The upper heat sink could also be screwed into the lower heat sink but then you need isolated screws.

The TEC is directly attached/soldered to the motor and the motor is attached to the upper heat sink by another small piece of metal and a cable tie. The fan is attached to the motor with a small belt wheel and glue.

Result:
I think the hot aluminum part get to about 100-150 Celsius, I measured the temp with a grill thermometer covered in thermal paste but can´t tell how accurate it was. I measured 0.4V and 0.25A with one candle and 0.67V and 0.54A with two. That results in 0.1W resp. 0.36W output power. The efficiency to produce electricity this way is not that impressive though. A candle produce about 25 Watts, that means 0.7% efficiency.. But who cares, everything this machine does will eventually end up in heat any way =) That is a bit interesting, you increase the room-heating speed (I think) but looses nothing..

It is a bit noisy to have running all the time. To find the optimal motor/fan => airflow/noise level will require some more experimenting.

Mod Proposals:
  • Skip the base platform and bolts and use it as a stove-fan.
  • Use two/four TECs side-by-side to multiply output power. Add a 5-10mm thick copper plate that covers all modules and then place the CPU-cooler on top of that.
  • Use a brushless DC motor and a suitable fan to make it noiseless.
  • Build in a slow motor beneath the platform to make the whole thing spin 360 degrees.
  • Put wheels on the platform.
Edit:
I have changed the motor to a "Tamiya 76005 Solar Motor 02 (Mabuchi RF-500TB)". Got it on Ebay. It´s incredibly strong at low RPM and I give it only 0.5V. A very good motor, but best of all, it´s quiet! I cannot hear it at 2m distance at full speed. It also gives stronger air flow. Now I can run it all time =)


Donations:
High effect thermoelectric modules are expensive. If you would like to see more of those experiments in the future, please consider a small donation.
Bitcoin address: 1BouwowuprgQrtUYgyzYnNvHyRYbLceqHg

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Joohansson (author) 1 year ago
Some more images.
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this is real wondful......where to buy this module? Except the TEC(we have in manufacture), i need the sink and fan, i also wanna try !

Joohansson (author) 4 months ago

Together with my other instructable and with the new fan.

DSC00318.jpg
KristineD4 days ago

Hi Sir!

May I ask what is the highest possible temperature for both hot and cold side? This could be a great help for my research. Email: kristaaynne@gmail.com Thank you.

Joohansson (author)  KristineD4 days ago
Hi,
200 degrees Celsius for both sides in my project, but that depends on your module.
Thank you:)
PhilippeG118 days ago

with a big solar cooking and peltier?

Kristy luo4 months ago

We are manufacture from China with more than 10years EXP in supply with TEC-thermoelectric module, but now feel puzzled about TEC and TEG, yes, maybe they are different, Tec is peltier , Teg is seedbeck, and use in different way. Do you know

the other different? like the pellet inside?

Seebeck and peltier are the same thing a peltier uses the seebeck effect to operate

Hey it really a great idea to operate a fan without consuming much electricity. The heat produced by the candle can be easily converted into electric energy using a thermoelecric generator. Thank you for sharing this information and if you want to know more about such devices then please visit
http://www.analogtechnologies.com/products.html

anurag26821 month ago

what is the use of copper tube nd we can use for heating different things

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anurag26821 month ago

what is the use of copper tube nd we can use for heating different things

1097939_699936770031899_1453756818_n.jpg
yrayapati1 month ago

hi

that was grate idea. now I want to do it for school science exhibition project.

miremi made it!2 months ago

Author thanks!

I made one. I used:

Zalman CNPS 3X 10€,

Old GPU cooler 4€

Old case fan 1€

Motor from old cd drive

Thermoelectric module from ebay 6€ 12V 60W TEC1-12706.

It takes about 2-3 hours to make it.

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Joohansson (author)  miremi2 months ago

Cool, nice work!!

I wish there was a way to use the heat generated by my 2009 27" iMac to use this project

repkid3 months ago

nice

sberrier4 months ago

I have family in the Philippines and it gets very hot, they have metal roofing with no insulation to stop the heat transfer in the attic, my question is this: is it possible to attach 30 or so TEG's to the underside of the roof (to the metal) and send wire to a bedroom to run a fan ?

Joohansson (author)  sberrier4 months ago
It should be possible as long as you can cool the other side of the TEGs enough. It would be pretty expensive though:)
sberrier4 months ago

Great Idea, would a brushless motor be more efficient?

Joohansson (author)  sberrier4 months ago
Thanks, sorry don't know that.
svijay19946 months ago

i am planning to do dis by myself..but confused as of to which TEG i should be buying on Ebay...can you help me out??

first try just use TEC, which is cheaper, you can contact with me!

Chelwy5 months ago

would you please make a tutorial video about how to assemble this project because I'm still not experienced to make projects like this

I'd be glad to wait for you tutorial video :)
thanks anyway

ssingh1365 months ago

I wan to get this full project. Where Can i Get this Project in India. Plz Help Me Someone.

vsubu6 months ago
sir ,we have planned to do this as our mini project. ..u said earlier tat the cost was about 50£..we r india...can we get that...any idea .. suggest us sir...
janni19776 months ago
Hello! Could you please tell me where I can buy the metal fan blade? I bought one @amazon but the centerhole seems to be too big for the motor.
Thank you so much!
Joohansson (author)  janni19776 months ago
I bought it in a store in sweden. I had to modify the hole and use a metal cylinder that fit the motor. But I replaced the fan with the plastic one from the CPU cooler because it was much more silent. That one too had to be modified though.
dreb8 months ago
Nice setup,
What do you think about integrating this with the popular 'flowerpot candle heaters' on youtube?

This way theoritically, you could have both heat by radiation and convection.
Joohansson (author)  dreb8 months ago
Nice idea! Have not seen that before. You could probably increase the effiency by combining that construction with this. Simply put the TEG module with heat sink and fan on top of the pot perhaps? Please let me know if you try that!
aporgatorio8 months ago
What do you think is its RPM and Torque... I plan to make and use this as a prime mover for our miniature generator research project,,,

but its not final... :P
Joohansson (author)  aporgatorio8 months ago
Good question, I have no idea or how to calculate that. Sorry =) But I think I gave the output power in the instructions, maybe you can calculate from that?
jimwi10 months ago
This is a thing of great beauty. I just love it. I have just ordered some parts to make one.
I have a technical question, would you know if there is any thing in the copper tubes on the big cooling heat sink, like liquid or a gas to help transfer the heat. I was just wondering because I think I can make one of these my self with some copper tube and aluminum sheet I have lying around.
Joohansson (author)  jimwi10 months ago
Thanks! I heard somewhere that there was some kind of fluid but I´m not sure. Maybe you can search in computer geek forums or something =) Please let me know what you find. Good luck with the construction!
jimwi Joohansson10 months ago
Man it took some looking to find the answer, if you don't use the right words in your search you get know wear. what I found is yes, not much but a few drops of distilled water in a small vacuum to lower the boiling point and a wick to draw fluid down. There not quite as simple as they look. Here's a link;
http://www.pcstats.com/articleview.cfm?articleid=2466
einstienusama11 months ago
can u tell me how to build it step by step...!! i cant understand it..! specially the aliment of heatstinks...and how to connect motor. plz email me @ hiddensecrets471@gmail.com

thanks in advance
Joohansson (author)  einstienusama11 months ago
Sorry, I will not describe it more than I already have. I think the description is good enugh. You will need some mechanical skills for this construction.
tanmoy_paul11 months ago
Hi,
I'm Tanmoy.
I'm making this to give a try to my project skills. Need some help like "which TEC module can we use other then the described here?". Also will be needing some more in few days, hope you help me...
Joohansson (author)  tanmoy_paul11 months ago
Cool, I think you can use almost any TEC for this, as long as it not get overheated.
244 Jake1 year ago
Back in about 1976, I apply for government money to study the use using the same ideas you show here. My test bed was Harly golf card, gasoline powered. I used second battery set to run the light, and radio. Monitored the power in and out on the electrical side, the gasoline engine supplied the heat. What was true then, and seeming still true, power to weight ratio, cost per watt produced, and space required per watt of power just doesn't compeat with anything you can't buy at the store.

BUT, as a thing to look aprons, a thing of craftsmanship what you did is wonderful. Eye candy for sure.

Big Jake
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