The PowerPot

[eh4]

Good health to you EZO, sorry you gotta repair from storms too but mostly wishing good health to you. -expect more storms I think for the forseeable future, we're getting pounded pretty hard here to on and off.

FWIW, one 5V module and one LVBoost converter would set you back about 40$. -For doing a hand/warmer -little led light project these would do the trick... and conceivably the whole thing could be Well under an ounce depending on how much metal you added.

I just broke the corner of one of the 5V by being too impatient and using surfaces that hadn't been ground flat enough, it still works and I still have the little broken off corner saved for putting back as a fitted patch when I get the right epoxy to pot the apparatus.
The fragility of the 5V unit is that it's just got wafer thin faces pre-coated in graphite for a good heat interface. Once you have the unit safely clamped down (8 inch pounds) with it's heat source surface and heat sink surface it should be fairly durable, I'm still concerned about shearing forces (say dropping it on it's edge) and I'm looking into high temperature ceramic epoxies that won't conduct heat well enough to mess up the TEG's temp differential.

If you went off the dimensions and got your hot and cool sides together, drilled, ground flat, dimensioned, etc. before you ever ordered the high tech parts you'd bypass most of the problems I've run into.

The 15V unit, while it costs nearly 4X as much as a 5V, already has durable sides, running 24/7 at it's rated power output in your Vermont winter, it looks like you could potentially get 10.8 KWh per 30 day month.

I've got some day to day stuff blowing up on me right now but when I get back to playing with TEG I'll do a little mock up for hot hands and cold water with LVBoost and a 5mm LED, will share those results with you -and then pretty much step back from the ultralight thermal emergency light project for your prototyping.
Also when I find the "good" epoxy I'll share that info too.
You can see my post in CPF green for some pics and more rambling but here is the best pic, powering a Malkoff M31WL with a tea candle and a trickle of cool water, lighting for the photo provided by the M31WL btw: http://imageshack.us/photo/my-images/252/20120304010800912.jpg/
Not as good of a pic but you get to see the M31WL doing it's thing.: http://imageshack.us/photo/my-images/259/2012030401250360.jpg/

I have been wanting to put together some fun, over the top Mad Max contraption that's basically a brazier full of coals on a stick, with spikes coming off of it of course, heating the TEG, and powering the M31WL, calling it "Fire on a Stick Mark V" or something goofy like that just to to be funny and make some CPFrs scratch their heads. The more bad *** and ultimately impractical the better.
I wouldn't mind having more money than sense. ;-)

 

[EZO]

eh4, Cool, thanks!

 

[shadowjk]

Maximum output occurs at maximum temperature differential. Indeed you can make power from "cold", if you have a TEG at room temperature and apply extreme cold to one side, it will put out power.

 

[eh4]

Check out this DIY: http://sparkbangbuzz.com/copper-oxide-te/copper-oxide-gen3.htm

and here is a slick overview: http://www.electrochem.org/dl/interface/fal/fal08/fal08_p54-56.pdf

 

[EZO]

Hi eh4,

As a result of our discussions on this topic a couple of weeks ago I ended up watching a video of this same presentation on Copper Oxide Thermoelectric Generators by Nyle Steiner so it's interesting that you would offer these links about it now.

Here it is for anyone who is interested:

 

[eh4]

Yeah it's funny how it works out.
I'm getting the bug really bad to make some more progress with TEG (gathering free time and resources) and was reading up last night when I found those links.
Thanks for the video version.

 

[EZO]

eh4, I know virtually nothing about this phenomenon, so I hope this isn't a totally dumb question but what might happen if one used larger oxidized copper rods instead of wires or two oxidized copper plates just touching each other instead of wires? Would you see more current and voltage, would the output be more or less the same as with wires, or would it just not work at all because there would be too much surface contact/resistance?

 

[EZO]

BTW, I see that the PowerPot Kickstarter project obtained their $50,000.00 goal within 9 days and as of this posting has pledges of $71.576.00 with 12 days to go, so the PowerPot should actually come to market.

And they've come up with another very practical use for it now that they've got the funding! :shakehead

 

[eh4]

That's a cool demo of how much power they can produce.
I only understand the effect superficially, kind of a slow learner -I could read everything about it but it isn't really my knowledge until I have enough experience and experiments... "dumb" questions are welcome -I certainly don't know enough about this subject to necessarily be able to answer them, besides they say that if you want to learn something you should try to teach it.

We know that the Seebeck effect is powered by the difference in temperature across the junctions.
We know that the junctions can be wired in series to increase voltage.
-my thought is that larger contact surfaces could result in more current at the same voltage, if the junction contact area was uniform, but it seems like irregularities in the contact would limit the gains... not sure if that's really any different than multiple junctions in parallel or not, but I don't think so.

I need to get tooled up for experiments, there is a serious lack of work space in my world at the moment.


My main concern/interests in their Powerpot design are:
1: how much power is generated when the water is heated to a useful cooking temperature? (practical cooking needs substantial simmer times)
2. how compromised is the cooking function vs, a comparable aluminum pot? (maybe only an issue for quick boil times and a non issue for sustained cooking)
3. under what conditions could the TEG unit be damaged/destroyed? (and are these TEGs instantly destroyed, or could we end up seeing gradual failures that escape early detection)?
-I would be more comfortable knowing that the device will operate continuously at a practical temperature with no risk of gradual failure... I'm currently under the impression that failure is pretty much instant when inner solder connections melt.

I want a 15V one, glad they got funded so quick!

 

[eh4]

reposting vanity pic,
light for picture provided by Malkoff M31WL powered by the TEG, which is heated by the candle, and cooled by the trickle of water siphoning through the copper tube.
Voltage regulated by LVBoost.
[URL=http://imageshack.us/photo/my-images/16/malkoffm31wlglare.jpg/]


Uploaded with ImageShack.us




Uploaded with ImageShack.us


http://imageshack.us/photo/my-images/252/20120304010800912.jpg/

[/URL]

 

[EZO]

My main concern/interests in their Powerpot design are:
1: how much power is generated when the water is heated to a useful cooking temperature? (practical cooking needs substantial simmer times)
2. how compromised is the cooking function vs, a comparable aluminum pot? (maybe only an issue for quick boil times and a non issue for sustained cooking)
3. under what conditions could the TEG unit be damaged/destroyed? (and are these TEGs instantly destroyed, or could we end up seeing gradual failures that escape early detection)?
-I would be more comfortable knowing that the device will operate continuously at a practical temperature with no risk of gradual failure... I'm currently under the impression that failure is pretty much instant when inner solder connections melt.

I want a 15V one, glad they got funded so quick!

eh4, Those demo shots of your home brew project look really cool! I love the way the Malkoff works for the photo and how you've powered it in a "loop".

Your questions about the PowerPot are right on target and some of them are addressed on the PowerPot web site FAQ to one degree or another.

They say: "We recommend that only water (or soup, tea, etc) be used in the PowerPot to achieve optimal power production. If possible, start with very cold water (or snow or ice). Using water will achieve the longest lifetime for a PowerPot and will produce the most consistent results."

They also say: "The whole package is rated to 600° F (315° C). This means the PowerPot can operate in an open-pit fire as well as in portable or home stoves."

They welcome questions via the submission form on their web site, so I guess you could ask them directly. I wonder too about the solder but I 'spose if it works over an open pit fire it should be OK for most applications.

 

[eh4]

Thanks EZO, that little project put a huge grin on my face when that warm led fired up, brighter and brighter.
Also shown is the basic trick that I'm working on for my application, overcoming the water boiling/diminishing heat differential problem by having running water...

For a small cabin, cooling the TEG could be accomplished with a water line preheating the water slightly (rather than heating it a lot and losing heat differential) before going on through the fire or into a water jacket or other water heater... or the water could just be run along to radiate heat for the house, I'd like to do a version of that where the warmed water goes to keep a little sunroom/attached greenhouse warmer on cold nights. DC pump powered by the TEG of course.

At 600 F heat limit, it sure seems like any cooking fire would be safe as long as there was water to boil off excess heat, my only concern there has to with my inability to fully understand (yet) the speed of heat conduction, how quickly the bottom pot surface can transfer the heat through the teg and to the water... It's the juncture between the teg and the hot side heat sink that's the concern, propane mixed with air burns at nearly 2000C for instance....if the bottom metal surface were too thin and allowed a hot spot to develop...
I need a laser thermometer.

Thanks for pointing out their question submission page. I may have a couple questions when I'm about ready to buy a model from them, the big 15V pot looks like a winner to me.


Also, EZO, if you look at their picture at the orange ring at the bottom of the pot, I'm pretty sure that's "the good stuff" ceramic epoxy I was talking about needing to source.

 

[eh4]

hey EZO, this looks promising for a micro TEG light, maybe a 5mm led or two, comparable to a Pak-lite... something about the size of a class ring would be pretty cool: http://www.micropelt.com/products/thermogenerator.php

 

[fonzerelli]

Interesting concept here.

Not to change the subject, but EZO, what kind of snake is that in your avatar?

 

[EZO]

hey EZO, this looks promising for a micro TEG light, maybe a 5mm led or two, comparable to a Pak-lite... something about the size of a class ring would be pretty cool: http://www.micropelt.com/products/thermogenerator.php

Hey eh4, That's an amazingly small footprint! It seems like such small modules would open up many interesting design possibilities. I can imagine something like incorporating a few of these in the hatband of a baseball cap that would power LEDs in the brim, or something like that. I wonder if the properties are any different at this size; for example the required heat differential being lesser or greater. So, perhaps the heat from one's head in a hatband would have enough of a temperature difference from the surrounding ambient air to produce a few volts for a couple of LEDs.

The link was interesting. As with the last ones you referred to, it was the charts that gave me the best understanding here. I was also intrigued by the little unit with the integrated finned heat sink which implies that it is intended to work with ambient air temperatures.

 

[EZO]

Interesting concept here.

Not to change the subject, but EZO, what kind of snake is that in your avatar?

Hi fonzerelli,

I do seem to get a lot of questions about my avatar. The last one was whether or not it is "real". It's a pretty large Eastern Garter snake and it is real. The photo is part of a series of "formal" portraits I've been working on where I bring critters into my studio for "sittings".

 

[fonzerelli]

Hi fonzerelli,

I do seem to get a lot of questions about my avatar. The last one was whether or not it is "real". It's a pretty large Eastern Garter snake and it is real. The photo is part of a series of "formal" portraits I've been working on where I bring critters into my studio for "sittings".

Thanks! I have to admit, I am pretty surprised that it's just a regular ole garter snake! I realize the photo lacks any sort of perspective, but that snake does look pretty beefy.

Cool photo.

 

[EZO]

Kickstarter just blows my mind. It's without doubt one of the most innovative and unique business models on the net. The guys behind the PowerPot were looking to raise $50,000.00 to get their project off the ground. Instead, they raised $126,204.00 with 1047 backers. Amazing!

 

[SemiMan]

Yeah, I checked out TEGpower after I found the Kickstarter PowerPot page. Interesting stuff. There are many interesting possibilities for this technology, especially considering how many things in our lives produce waste heat.
I particularly like the idea of using the heat from an automotive exhaust manifold or the idea of using thermoelectrics instead of photovoltaics in solar applications with a much smaller footprint. I primarily heat with wood and that too opens up some interesting uses for a PowerPot or other similar use of thermoelectrics.

Automotive exhaust heat, etc. etc. are all concepts from 20-30 years ago for thermoelectrics. The killer is always the lack of efficiency in the power conversion and so far it has not gotten much better ... hence why solar is better in most applications as well. Think how much energy needs to be wasted in order to generate just 5watts of electricity. The great thing is it is on demand. You can't fault that. A light weight flexible solar panel even on cloudy days can collect a lot of energy .... but not at night obviously.

I wish them well. I think they will tap into a reasonable sized niche market for people who want it though I can't say it will be high on my camping list .... given my little hand crank generator puts out more power than their base unit.

Semiman

 

[EZO]

Automotive exhaust heat, etc. etc. are all concepts from 20-30 years ago for thermoelectrics. The killer is always the lack of efficiency in the power conversion and so far it has not gotten much better ... hence why solar is better in most applications as well. Think how much energy needs to be wasted in order to generate just 5watts of electricity. The great thing is it is on demand. You can't fault that. A light weight flexible solar panel even on cloudy days can collect a lot of energy .... but not at night obviously.

I wish them well. I think they will tap into a reasonable sized niche market for people who want it though I can't say it will be high on my camping list .... given my little hand crank generator puts out more power than their base unit.

Semiman

As far as automotive exhaust heat or wood stoves are concerned, it seems that much of this type of heat goes to waste anyway so you're just making use of something that is already there rather than having to generate the energy in the first place and therefore the effiency is less relevant. This was why the idea interests me as I'm running a woodstove anyway, and would be tapping into what would amount to a relatively miniscule amount of the energy coming off the stove.

Tell us more about your hand crank generator. What happens when you stop cranking?