Thermopile Generator

[Al]

A number of years ago, I read about a hiker who built a portable
thermopile generator. He used a metal smokestack pipe as a flue he would
place over a campfire. The smoke stack looked like a porcupine as
bimetallic elements were sticking out from it perpendicular to the
surface. Supposedly it generated enough current for him to run radios
and the like.

I've lost the reference to it. Does anyone have any idea where I might
find it? Googling had been useless as all it brings up are Honeywell
700mv thermopiles for gas heating systems.

Al

 

[Luhan]

A number of years ago, I read about a hiker who built a portable
thermopile generator. He used a metal smokestack pipe as a flue he would
place over a campfire. The smoke stack looked like a porcupine as
bimetallic elements were sticking out from it perpendicular to the
surface. Supposedly it generated enough current for him to run radios
and the like.

I've lost the reference to it. Does anyone have any idea where I might
find it? Googling had been useless as all it brings up are Honeywell
700mv thermopiles for gas heating systems.

Al

Today, it may be much easier to carry a solar panel. About 1 square
foot of
solar panel puts out about 12 volts and 400 ma. And you dont need
matches.

Luhan

 

[Dirk Bruere at NeoPax]

Today, it may be much easier to carry a solar panel. About 1 square
foot of
solar panel puts out about 12 volts and 400 ma. And you dont need
matches.

Not too good around the campfire at night though.

Dirk

 

[Electric dabbler]

Not too good around the campfire at night though.

Dirk

Hi Al,

What about Peltier effect devices?

These are mostly used to cool but I sort of read somewhere they can generate
a current if there is a big thermal differnce between the two sides.

Philip

 

[BobG]

I went down to my local HVAC parts store and bought one of those
Honeywell thermopiles (they are supposed to detect the pilot light and
generate enough juice to hold the relay open that supplies the pilot.
If it blows out, the gas shuts off). They are about $35 ea. I couldn't
get 700mv out of it... tried the hot air gun, fire... I was hoping
several of em in series might be able to fire up a wide input dc to dc
switcher. Results so far are inconclusive...

 

[GregS]

Hi Al,

What about Peltier effect devices?

These are mostly used to cool but I sort of read somewhere they can generate
a current if there is a big thermal differnce between the two sides.

I just happened to measure that this morning. Not much voltage at all at only a few degrees
difference, but as long as the thing does not melt, it should work up into a couple hunderd degrees.

greg

 

[John Woodgate]

I went down to my local HVAC parts store and bought one of those
Honeywell thermopiles (they are supposed to detect the pilot light and
generate enough juice to hold the relay open that supplies the pilot.
If it blows out, the gas shuts off). They are about $35 ea. I couldn't
get 700mv out of it... tried the hot air gun, fire... I was hoping
several of em in series might be able to fire up a wide input dc to dc
switcher. Results so far are inconclusive...

They produce about 40 uV per degree Celsius per junction. So at 400 C,
you should get 16 mV per junction.

Thermocouples are VERY low impedance sources. You can work a solenoid
with one at red heat.

 

[Phil Hobbs]

Hi Al,

What about Peltier effect devices?

These are mostly used to cool but I sort of read somewhere they can generate
a current if there is a big thermal differnce between the two sides.

Philip

I've heard of people using thermoelectric coolers between their Coleman
stove and cooking pot, to generate electricity at camp. You'd want to
use the ones that can stand thermal cycling, of course--try Ferrotec.
The cheaper ones are made with soft solder, and won't stand much
cycling--like 100 cycles MTBF.

Of course, you could use a small steam engine running a bicycle
generator.....

Cheers,

Phil Hobbs

 

[Barry Lennox]

A number of years ago, I read about a hiker who built a portable
thermopile generator. He used a metal smokestack pipe as a flue he would
place over a campfire. The smoke stack looked like a porcupine as
bimetallic elements were sticking out from it perpendicular to the
surface. Supposedly it generated enough current for him to run radios
and the like.

I've lost the reference to it. Does anyone have any idea where I might
find it? Googling had been useless as all it brings up are Honeywell
700mv thermopiles for gas heating systems.

In Pierre Lorain's excellent book "Secret Warfare" he describes one
made by SOE for resistance use during WW2. It had 350 thermocouples
(Cn-Cr) in a brazier. With a small fire it could charge a 6 volt
battery at 1 Amp. I have seen a photo of one, but can't recall where
now. It looked to be about 5-6" diameter and maybe 10-12" high.

Barry Lennox

 

[Kevin White]

A number of years ago, I read about a hiker who built a portable
thermopile generator. He used a metal smokestack pipe as a flue he would
place over a campfire. The smoke stack looked like a porcupine as
bimetallic elements were sticking out from it perpendicular to the
surface. Supposedly it generated enough current for him to run radios
and the like.

I've lost the reference to it. Does anyone have any idea where I might
find it? Googling had been useless as all it brings up are Honeywell
700mv thermopiles for gas heating systems.

Al

I coulnd't find a reference to currently available ones but there are
many to ones from the 1920's and later.

kevin

http://www.dself.dsl.pipex.com/MUSEUM/POWER/thermoelectric/thermoelectric.htm
http://www.navitron.org.uk/TEG_lantern.htm
http://www.hi-z.com/
http://www.its.org/
http://www.hi-z.com/websit06.htm
http://www.audiodesignline.com/showArticle.jhtml?sssdmh=dm4.162031&articleID=175700512
http://wantitnow.ebay.com/Russian-T...sene-Hanging-Lamp-1950s_W0QQadidZ140008690541

 

[Tim Williams]

Seeback(?) effect is really inefficient. I don't know what exotic compounds
and intermetallics can do, but I recall the best not-too-exotic combination
is silicon and germanium.

As I recall, such was used in Voyager 1 and 2 or so, combined with a ball of
plutonium, to produce 100 watts or so.

Tim

 

[Spehro Pefhany]

Seeback(?) effect is really inefficient. I don't know what exotic compounds
and intermetallics can do, but I recall the best not-too-exotic combination
is silicon and germanium.

As I recall, such was used in Voyager 1 and 2 or so, combined with a ball of
plutonium, to produce 100 watts or so.

Tim

IIRC, I've seen electric fans that sit in a stovepipe and derive their
power from tapping the temperature gradient from the air to the
outside of the pipe.



Best regards,
Spehro Pefhany

 

[martin griffith]

Seeback(?) effect is really inefficient. I don't know what exotic compounds
and intermetallics can do, but I recall the best not-too-exotic combination
is silicon and germanium.

As I recall, such was used in Voyager 1 and 2 or so, combined with a ball of
plutonium, to produce 100 watts or so.

Tim

As I recall, such *are* used in Voyager 1 and 2 or so, combined with a
ball of plutonium, to produce 100 watts or so.

Good stuff those Voyager missions
http://www.physorg.com/news74969265.html


martin

 

[Rich Grise]

They produce about 40 uV per degree Celsius per junction. So at 400 C,
you should get 16 mV per junction.

Thermocouples are VERY low impedance sources. You can work a solenoid
with one at red heat.

So, would you do something like this?

o---------Chromel--------v
v-----Alumel---------^
^-----Chromel--------v
v-----Alumel---------^
|
...
|
^-----Chromel--------v
v-----Alumel---------^
^-----Chromel--------v
o---------Alumel---------^

v
^ = spot-weld

Thanks!
Rich

 

[default]

A number of years ago, I read about a hiker who built a portable
thermopile generator. He used a metal smokestack pipe as a flue he would
place over a campfire. The smoke stack looked like a porcupine as
bimetallic elements were sticking out from it perpendicular to the
surface. Supposedly it generated enough current for him to run radios
and the like.

I've lost the reference to it. Does anyone have any idea where I might
find it? Googling had been useless as all it brings up are Honeywell
700mv thermopiles for gas heating systems.

Al

Thermopiles aren't forgotten. Your search techniques needs
improvement - if Honeywell comes up too often put a minus sign in
front of it when you search. Or use google advanced search and put it
in the block marked: "without the words"

Use Scroogle and put a -com and you get the edu, org, gov, etc., sites

I remember reading a Scientific American, Amatuer Scientist article on
the subject. It is basically a large number of thermocouples wired in
series. They showed a design where two wooden doughnuts have the
iron/copper thermocouples between them with all of one set of
junctions on the inside of the circle (the hot side) and the opposite
side on the outside with a bunsen burner heating the hot side. Wires
were about 8" long . . . iron,copper,iron,copper, etc..

The Rusians used a large number of thermopiles heated with decaying
radioactive isotopes to heat the hot side. They were used in their
space program and in remote areas to send telemetery data back to
base.

See
http://www.capgo.com/Resources/Temperature/Thermocouple/Thermocouple.html

read to the end where it mentions thermopiles

 

[Winfield Hill]

Barry Lennox wrote...

In Pierre Lorain's excellent book "Secret Warfare" he describes one
made by SOE for resistance use during WW2. It had 350 thermocouples
(Cn-Cr) in a brazier. With a small fire it could charge a 6 volt
battery at 1 Amp. I have seen a photo of one, but can't recall where
now. It looked to be about 5-6" diameter and maybe 10-12" high.

There was scarcely a shortage of brave Frenchman during the war,
nor of brave Englishman (and women of course). Anyone caught
by the Germans with one of those large thermopiles was a goner.

 

[Homer J Simpson]

There was scarcely a shortage of brave Frenchman during the war,
nor of brave Englishman (and women of course). Anyone caught
by the Germans with one of those large thermopiles was a goner.

Nor, ironically, of brave Germans who opposed the Nazis. In fact there was
more opposition in Germany than in France, impressions to the contrary
notwithstanding.

 

[Barry Lennox]

Nor, ironically, of brave Germans who opposed the Nazis. In fact there was
more opposition in Germany than in France, impressions to the contrary
notwithstanding.

Actually all across Europe. I do recall seeing in a memorial
somewhere, to the Resistance, the numbers in various countries.
France was pretty well down the list, which was a bit of a shock to
me, as I grew up hearing and reading all about the "French"
resistance. I understand that the French numbers grew a lot when it
was apparent an invasion of France was coming.

But anyway Win is correct. Torture and death awaited anybody caught
with any part of a radio, generator, weapon, etc. And indeed even
being out on the street when the Nazis took reprisals.

The crying shame is that many of the offenders walked away without
penalty.

 

[Robert Latest]

On Mon, 21 Aug 2006 03:16:21 GMT,

There was scarcely a shortage of brave Frenchman during the war,

[...]

Nor, ironically, of brave Germans who opposed the Nazis.

There was definetely, by definition, a shortage of those. Otherwise the
Nazis wouldn't have come to power.

Dictionary.com: "Shortage: A deficiency in amount; an insufficiency."

robert

 

[Al]

Thermopiles aren't forgotten. Your search techniques needs
improvement - if Honeywell comes up too often put a minus sign in
front of it when you search. Or use google advanced search and put it
in the block marked: "without the words"

I was looking for the specific one mentioned above, i.e., the hikers
portable thermopile generator.

And Google has become more or less useless nowadayws. Most of the stuff
that comes up in the top 20 or so are adware.

I know, Google has to make money, but soon only the impulse buyers will
be using it.

Al