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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

Joohansson (author) 1 year ago
Some more images.
DSC_4379.jpgDSC_4370.jpgDSC_4394_night.jpgDSC_4380.jpgDSC_4385.jpgDSC_4382.jpg

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) 14 days ago

Together with my other instructable and with the new fan.

DSC00318.jpg
svijay19942 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!

Kristy luo21 hours 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?

Chelwy20 days 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

ssingh1361 month ago

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

vsubu1 month 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...
janni19772 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)  janni19772 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.
dreb3 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)  dreb3 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!
aporgatorio4 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)  aporgatorio4 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?
jimwi6 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)  jimwi6 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 Joohansson6 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
einstienusama6 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)  einstienusama6 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_paul7 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_paul7 months ago
Cool, I think you can use almost any TEC for this, as long as it not get overheated.
244 Jake9 months 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
Joohansson (author)  244 Jake9 months ago
Cool, thanks! It's now the main decoration on an old fire stove in a wood house we bought recently:) I'm running it right now.
hi sir,
iam rajesh
shall i get the total material which is assembled

pnadig9 months ago
Can a similar model be designed by replacing candle by a solar thermal collector system?
Joohansson (author)  pnadig9 months ago
I´m sure it can but it would be way more efficient to just use solar panels =)
agis6811 months ago
greate!!!! where you get the metal blade?
X[T]R[E]M[E]11 months ago
Can You tell from where did you buy those two heat sinks or can you provide name for those two of them!?? PLEASE we have to build our science project based on dis!!!?PLEASE........
Joohansson (author)  X[T]R[E]M[E]11 months ago
All info in the description. I did not buy the second one, also in the description.
Could you take a picture of how you mounted the motor to the fins?
Joohansson (author)  TakeTheCann0lis12 months ago
Check my last image, that´s quite good I think. It´s just a 1mm aluminum plate with two holes and a cable tie.
Okay so I'm just about finished with assembly, but now i realize I have no idea how to attach my propeller to the smooth spindle of the motor. Any ideas? Incidentally, the propeller hole is slightly larger than the motor spindle. I was thinking that I could take bicycle inner tube rubber and wrap it around the spindle.
Joohansson (author)  TakeTheCann0lis11 months ago
Yes that was a bit complicated. I was lucky and had a small wheel with matching axis diameter as motor. I modified the outer diameter to match the fan blades and then glued them together. Maybe you can find a small cogwheel or something from an old printer, floppy drive or other electronics with motors.
I finally realized that a champagne cork would make for a perfect nose cone!
IMG_0104.JPGIMG_0105.JPG
You could epoxy a small shaft collar to the back of the blade, concentric with the center hole. Tighten the set screw against the shaft and it shouldn't have an issue, though it might slip if the fan blade was bumped.
turtledrake11 months ago
Very Artistic and wonderfully functional.
noglider11 months ago
Very clever and interesting! Now I wonder how to compare the cost of "fuel" i.e. comparing electricity with wax. Scaling this project up, we can generate power by burning wood or whatever. Would that make sense? I know, it's a vague question and a complex issue.
Joohansson (author)  noglider11 months ago
Thanks! This is one of the most inefficient way of creating electricity so I would not recommend scaling it up:) I'm working on a more useful project though, check back soon!
power00012 months ago
I am glad about your moter.
What do you mean "Skip the base platform and bolts and use it as a stove-fan". What will use for base?
And, where did you found that metal blades for the fan?


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