Thermo-electric torch!

[Paul Baldwin]

Hey
I just stumbled across this and wondered if any of you might be interested?
http://thermalforce.de/img/product/module/big/m101.jpg

technical data:

• Size, (l x w x h): 150 x 26 x 35 mm.
• weight: ca. 100 g.
• system: direct to air
• number of thermocouples: 508
• match load output power: 0,07 W
• match load output voltage: 4,50 V
• switching frequency: 500 kHz
• Heat flux across the heatsink: about 8 Watt
• used LED: Nichia, 18.000 mcd

I was researching generators as I've been using my wood burning stove to light a couple of Cree 3w leds and they appear to make exactly what I hope to achieve aswell as this.
From what I've seen on CPF there are some on here that I'm sure could better it!

Paul.

 

[oregon]

Interesting. Thank you Paul.

Pics of your generator. Please.

I use a thermoelectric powered fan on my wood stove (pics in a few). It would be a real treat to be able to enjoy the light from efficient LEDs using the stove as the power source any time and useful in particular when the power goes out.

oregon

 

[Paul Baldwin]

Hi oregon,
it's in its infancy I'm afraid lol. I have just been proving the principles to myself so far and seeing what temperatures work. All I have done is rip the guts out of a 12v mini fridge and see what it generates. I need to buy either a proper 40mm TEG or a high wattage TEC first. I was also toying with the idea of buying an IFX-14 heatpipe as a more efficient method of cooling it. The problem I have is sparing the cash I also need a 5v fan as the 12v ones I have are no good for this.
I've seen the ecofans and fancied making my own, I'm sure I can make a working equivalent for less than the £100 they cost over here!

 

[oregon]

A stove/generator/LED pdf from the Mechanical Engineering dept. @ Colorado State University:
http://www.repp.org/discussiongroups/resources/stoves/ethos/mastbergen/Mastbergen_ETHOS_2005.pdf

I've seen abbreviated versions (two blades) of the Eco fans on sale online here for about $50 before.

A few pics of the stove/generator/fan at my homestead (the fan is moving as this is how we heat the house, 2500sf, when it is freezing outside):

http://i19.photobucket.com/albums/b188/oregun/P1130772.jpg

http://i19.photobucket.com/albums/b188/oregun/P1130774.jpg

Make some for sale Paul.

oregon

 

[Paul Baldwin]

Thanks for the link I've actually seen that in my searching!
The ecofan is certainly a very simple and elegant design. The idea of dissipating enough heat so that it doesn't kill the peltier is as I was hoping to achieve. Hopefully then you can use the more widely available and cheaper ones. The one I have is only rated to 49W and 138 degrees C. The stovetop approaches 250.

 

[JBorneu]

So ... is that a torch that uses the heat of your hand to run? That seems pretty cool. A shake torch would be better in cold situations, but as long as the temperature of your hand sis high enough, this woould be so much better. No shaking, no magnetic field to deal with ...

 

[Paul Baldwin]

Yes, that's exactly what it is I would have thought it would work better in cold situations, aslong as your hand is warm enough that is. The greater the difference between the "hot" part and "cold" the better it should work.
It's not cheap mind, I inquired on prices for the generator and the torch was included in the list. Its retailing at 124 Euros + 38 Euros postage.
They are the first production run devices of this type that I've seen anywhere tho!
Wish I had more funds available to make my own. Trouble is I need to buy a 2d maglite with a pill for an mc-e for a projector project yet and the auction for a heatpipe I was watching ended early.
Paul.

 

[baterija]

Yes, that's exactly what it is I would have thought it would work better in cold situations, aslong as your hand is warm enough that is. The greater the difference between the "hot" part and "cold" the better it should work.

I think the "as long as your hand is warm enough" is the key factor. It hit 0F (-18F) here just before sunrise yesterday with strong winds dropping the wind chill to around -25F (-32C). I triple dog dare you to hold that light in your bare hand!

Humor aside, this is a pretty neat idea. Thanks for catching it and sharing.

 

[grinsekatz]

Very interesting. In the description they say it is a development engineering to proof that it works.
I like the idea of this light but I'm afraid that a shake torch is still the better choice.
BTW: have you ever seen three anglers in the dark "charging" their shake torches?

Alex

 

[Paul Baldwin]

Pics of your generator. Please.

Hi oregon, I had a little mishap with my generator fan and now I need to replace the element I remembered mentioning it in this thread anyway so I thought I'd post a couple of pics of what I ended up with. Sorry about the delay

I strap it with copper wire to the stovepipe just above the stove and it works ok
I've been thinking more about the device this thread was started about too. It seems everyone is avoiding active cooling with the SST-90's and the like. You could use one of these elements to produce enough electricity to drive the fan from the heat differential. Therefore not creating anymore drain on your torches batterys and increasing cooling efficiency at the same time? It seems devices like this http://www.candlepowerforums.com/vb/showthread.php?t=262880 are going to be needing a solution like this? :candle: