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Conventional alternative energy systems => All other conventional alternative energy creation systems => Topic started by: conradelektro on August 16, 2012, 01:23:38 PM

Title: Thermoelectric generator - candle and cold water
Post by: conradelektro on August 16, 2012, 01:23:38 PM
It is a very old idea, electricity from a temperature difference. The effect is called "thermoelectric effec" or "Seebeck effect", see for instance http://en.wikipedia.org/wiki/Seebeck_effect#Seebeck_effect (http://en.wikipedia.org/wiki/Seebeck_effect#Seebeck_effect) .

I used two Peltier elements in series with a size of 30 mm x 30 mm x 3.6 mm each http://uk.farnell.com/multicomp/mcpe-127-10-13/peltier-cooler-38-1w/dp/1639751 (http://uk.farnell.com/multicomp/mcpe-127-10-13/peltier-cooler-38-1w/dp/1639751)

Each Peltier element is held between two flat aluminium bars, one hot and the other cold. Heat is provided by a candle and coldness by cold water (in a container).

See the attached photos showing a crude contraption. The output is up to 2,8 Volt (no load, 10 Mega Ohm digital volt meter, two Peltier elements in series) and up to 80 mA (short circuit current).

When running a Joule Thief driving a gutted CFL or a 220V 1W LED lamp, the Voltage holds at about 1,25 Volt and the current is about 68 mA (about 80 mW). Of course neither the gutted CFL nor the 220V 1W LED lamp have full brightness.

An output of 80 mW is not much, but with a better design and more powerful Peltier elements an output of 1 Watt seems to be feasible.

I found very good Peltier elements for electricity generation at http://thermalforce.de/de/product/thermogenerator/index.php?uid=f06c1126a7b53e606196e78a328e41e9&ref= (http://thermalforce.de/de/product/thermogenerator/index.php?uid=f06c1126a7b53e606196e78a328e41e9&ref=) but one probably can also find some in the US or elsewhere.

A design I will try next is depicted in the attached drawing.

The difference between cooling elements and generator elements is in the temperature resistance. There are generating elements which can be run at several hundred degrees (centigrades) of temperature difference. The cooling elements are designed for a temperature difference of about 70° (centigrades).

The basic idea:

During winter (where I live) one just has to put a bucket of water outside to cool it to freezing temperatures. In the house one then uses a candle as heat source (and cold water) to drive a thermoelectric generator which could power a small reading or novelty lamp.

I like to light a tiled stove during winter, which could also provide heat for a thermoelectric generator (again coldness from cold water).

The cold water is of course heated up over time and has to be exchanged every hour or so (depending on the volume of the cold water container).

Greetings, Conrad
 
Title: Re: Thermoelectric generator - candle and cold water
Post by: Pirate88179 on August 17, 2012, 04:53:54 AM
Conrad:

I was thinking of exploring this area myself after reading a 1951 Physics book explaining thermocouples.  They said it was just 2 dissimilar metals, they used copper and iron, and one coil at one end cold and another coil at the other end hotter than the other coil...and....electricity!!!!  No degradation of materials and you could use a whole bunch of them I am guessing and add up the power or volts.  I also am rethinking the Stubblefield coil in that...it used copper and iron wire and a coil was in the ground.  Well, here in KY where he lived, the ground temp is 54 degrees year around as that is the average temperature.  Well, it gets well over 100 degrees here in the summer so, that is a pretty good differential.  So maybe that is part of how he did all of that?  Who knows.  I will follow your experiments here with much interest.

Bill
Title: Re: Thermoelectric generator - candle and cold water
Post by: Magluvin on August 17, 2012, 06:36:02 AM
I havnt tried using them as a gen yet but with 2 modern cpu heasinks and cpu blower fans(squirrel cage) and a peltier chip, with 12v at 1 amp per fan and around 4 amps for the chip, it is a small solid state A/C unit.

Sitting on the bench, blowing the cold side on me and the warm side elsewhere, I had to tun it off after a while as I was a bit chilled. ;]

A guy has a candle powred deal on YT where he actually runs a fan to cool a PC cpu heatsink, for the 'cold side' , with a candle on the hot side.
The cooling fan runs off of the output of the chip.  :o ;)   Candle powered fan.

I have that on my list. ;]

They have campfire chargers also. Charge and run devices on a camping trip with the camp fire. Survival outlets have them.

If ya think about it, per square area, these might give out more in a solar application that solar cells. The cooling side will have to be dealt with. The hot side is easier.

Now, there was the woman who was a biologist, that invented a sun powered micro refrigerator, using what she learned in biology about how our bodies get rid of heat.

2 aluminum containers, same height, 1 is smaller in diameter to have some space between the container walls if we insert the smaller one into the larger one.

The outer container has many small holes or larger holes with a screen wrapped around it.  In the space between the container walls, you put sand, dirt, sponge, what ever that might absorb water.

Put an insulated lid on it and put it in the sun. The evaporation through the screen/holes brings down the inner container to 42 deg F.   :o :o

Now, if those efforts were combined, the sun can be used to 'power' the hot side of the chips, and the 'cold' side. And if we consider the amount of heat on the hot side of the chip from the sun, then the solar refrigerator would be better than just running a lot of water for the cold side. ;]

Very neat devices. And ebay has them in bulk for great prices. And many sizes to choose from.  I think they come in 6in x 6in.   :o :o ;)

MaGs
Title: Re: Thermoelectric generator - candle and cold water
Post by: Pirate88179 on August 17, 2012, 06:43:52 AM
Mags, I like the solar aspect to this...never thought about it.  What about a bunch of peltier junctions floating on a lake or pond, with the cold side in the water, and the hot side facing the sun?  I believe that there is a lot more that can be done with these than is being done at the moment.  Or, perhaps mounted in the back of our freezers with the cold side...and the hot linked to the cooling coils that are very hot.....we pay for this cooling anyway so....sort of "free" electricity?

Bill
Title: Re: Thermoelectric generator - candle and cold water
Post by: Magluvin on August 17, 2012, 07:49:51 AM
Hey Pirate

Well, we could use the heat of the fridge to power the hot side. If you look around for info, the ratio for hot side and cold side to get decent power out is 'hot' and 'cold'. So heat from the fridge for the hot, where do we get the cold? If we get our cold side from A/C in the home, then the A/C has to work harder to keep the fridge coils cooler, through the peltier gen, So maybe the energy from the peltier is free? And all from heat just passing from the fridge to the home A/C unit? ;]  Being that the fridge is heating the house anyway, that the A/C cools, that loss is inherent. So the peltier gen output is a gain. The heat from the fridge through the gen, then into the open air, wont make the house any hotter.  ;] It is what it is.  ;]

So put 50 of these chips on the back of the fridge, mount aluminum heat sinks to the cold side of the chips, lol, then power and inverter to run the fridge, with inherent losses that exist in the house already.  lol  im nuts.  ;) Maybe not. :o


There is a lot of vids on YT that are inspiring with these chips. Their efficiency is not great.
That when I decided that the candle power, if it could charge a phone, that would make me forget about the efficiency fast. The outcome would be worth it in power outages, or other things like disasters like hurricanes. 

Thinking about it further, then I came up with the sun powered hot and cold side. ;]

I want to get like 10 of these and try to make a small solid state A/C unit. Just to see what a larger scale of what I did with 1 works like.

The single is about 70 watts fans and all at 12v. Times 10, 700 watts. Like a smaller wall shaker unit, maybe less.  And 20 fans included in that estimate would create a lot of wind. These are not the simple bladed pc fans.

I find that it is best to use more fan and fins for the hot side. The faster you get rid of the hot side heat, the better the cooling on the cold side.  Like in your car, if you put the ac blower on low, the air coming out is colder.

So maybe the 20 fans could be divided to have more of them on the hot side, and less on the cold. Then if you want the solid state ac to be a heater, just reverse the chips input polarity.  ;]  They supposedly run best at near 16v input. As a gen, the voltages are more like less than 10v, closer to 5v, depending on the heating and cooling design. As a gen, the candle will get the hot side hot, so in the gens case, we also want to get rid of the heat from the opposite side of the chip as fast as possible for best results.

You can series and parallel them for greater outputs.  And series the chips physically also, so 10 chips for the SS A/C unit, 5 stacks of 2 chips would do close to the same job as all 10 laid out on heat sinks.

Computer shops will sometimes have boxes of these heat sinks and fans that you can get from them dirt cheap, from the right guy. Comp usa has good prices on new also.

The chip is only as good as the design of the application. ;]



MaGs
Title: Re: Thermoelectric generator - candle and cold water
Post by: TinselKoala on August 17, 2012, 10:02:32 AM
TK likes this.
Two thumbs up!
 :)
Title: Re: Thermoelectric generator - candle and cold water
Post by: conradelektro on August 17, 2012, 11:08:02 AM
TinselKoala & Pirate88179: thank you for the encouragement.

Magluvin: thank you for the good information (camp fire charges, aluminium boxes). I hoped to get feedback by creating a thread, and in come the great ideas. There are so many things out there which one can learn.

Efficiency: I read that NASA achieves about 7% efficiency in the latest Mars rover (2000 Watt of heat from the plutonium, about 150 Watt electricity out from the thermocouples) http://solarsystem.nasa.gov/rps/rtg.cfm (http://solarsystem.nasa.gov/rps/rtg.cfm) . The easily available elements reach about 4%.
 
From this web site http://thermalforce.de/de/download/index.php?uid=f06c1126a7b53e606196e78a328e41e9&ref= (http://thermalforce.de/de/download/index.php?uid=f06c1126a7b53e606196e78a328e41e9&ref=) (sorry, most of it in German) I learned a lot.

For electricity generation one wants a high temperature difference (100° or 200° centigrades difference), that really boosts the output (to near 4% efficiency). One also has to assure a good heat transfer from the Peltier element to the cooler/heater and they sell a lot of glues and pastes for that http://thermalforce.de/de/product/waermeleitmittel_zubehoer/index.php?uid=f06c1126a7b53e606196e78a328e41e9&ref= (http://thermalforce.de/de/product/waermeleitmittel_zubehoer/index.php?uid=f06c1126a7b53e606196e78a328e41e9&ref=) (again in German). I am not a sales person for this German firm but I am so happy to have found a source that sells one or two items to me.

May be some one knows US sources and info in English.

All winter from September to May I often light two tiled stoves in my house (kitchen and living room) because it creates a very comfortable atmosphere. And I want to combine this habit with a battery charger (during the day) or a lamp (in the evening) based on Peltier elements. Nothing new, but I want to come up with a simple and practical set up.

See the attached drawing for a principal lay out. The cold water container should be mounted on the outside of the house (the stove is on the inside of the wall) and two pipes lead to the heat exchanger at the Peltier elements (which are basically glued to the stove). One pipe feeds the cold water and the other returns the slightly warmer water (after it went through the heat exchanger) back to the cold water reservoir. If set up in the right way convection should start by itself.

In the sixties all water heating systems (with radiators in each room and a burner in the basement) were build to self convect. Nowadays one uses an electric pump to move the water through the pipes and the radiators because that allows for more freedom when installing the pipes and the radiators around the house.

All this is of course not new and probably not OU (but will be patented to make me rich, all rights reserved). My wish is to come up with a system that is easy to install and with commonly found (and hopefully low cost) components (besides the Peltier elements which cost about 50.-- Euros a piece). I also do not want to destroy my house or to install a really awful looking contraption. But sacrifices have to be made in order to advance science.

Greetings, Conrad
Title: Re: Thermoelectric generator - candle and cold water
Post by: conradelektro on August 17, 2012, 01:00:08 PM
Here the camp fire charger mentioned by Magluvin (I like it):

http://www.youtube.com/watch?v=J2rA9XK_6wI (http://www.youtube.com/watch?v=J2rA9XK_6wI) (unboxing video)

http://biolitestove.com/campstove/camp-overview/features/ (http://biolitestove.com/campstove/camp-overview/features/) (2 Watt at 5 Volt)

http://biolitestove.com/homestove/overview/ (http://biolitestove.com/homestove/overview/)


Here a rather complicated description of a cooling system with two flower pots, sand, water and a paper kitchen towel:

http://www.ehow.com/how_7504579_diy-water-cooling-system.html (http://www.ehow.com/how_7504579_diy-water-cooling-system.html)


Greetings, Conrad
Title: Re: Thermoelectric generator - candle and cold water
Post by: TinselKoala on August 17, 2012, 06:06:29 PM
Can these Peltier elements be completely submerged in oil? If so that would really help with the heat transfer, going in either direction. A non-pumped, convective flow of oil submerges the element and a high-efficiency heat exchanger interfaces with the environment or outside heat source/sink.
One side of the Peltier module is contacting (submerged in) one sealed oil chamber and ditto the other side of the module, one side hot, the other side cold.
Title: Re: Thermoelectric generator - candle and cold water
Post by: conradelektro on August 17, 2012, 07:45:07 PM
Can these Peltier elements be completely submerged in oil? If so that would really help with the heat transfer, going in either direction. A non-pumped, convective flow of oil submerges the element and a high-efficiency heat exchanger interfaces with the environment or outside heat source/sink.
One side of the Peltier module is contacting (submerged in) one sealed oil chamber and ditto the other side of the module, one side hot, the other side cold.

The Peltier elements I have consist of two thin ceramic plates (non conducting) and the thermo coupled metals are sandwiched in between. Additionally there are two wires leading out from in between the ceramic plates. (See the Peltier element in the attached photo montage.)

The ceramic plates could each be a wall of a container, one container with hot liquid and the other with cold liquid. One needs a good glue (heat resisting glue for the hot side) and a suitable design / geometry of the containers.

I kind of go half there with may next design. I use a 110 mm diameter evacuation tube (PVC) with an end cap at the bottom as a cold water container. The end cap carries an aluminium plate with holes. And the cold ceramic plates of two Peltier elements will be glued over the holes. The cold water will be able to reach the aluminium plate but also the ceramic plates through the holes.

One wants the cold ceramic plate at the bottom of a cold liquid container, because the liquid which becomes a little warmer will rise being replace by the coldest liquid in the container by natural convection.

One wants the hot ceramic plate at the top of a hot liquid container, because the liquid which becomes a little colder will sink being replaced by the hottest liquid in the container by natural convection.

But in my next build I will only use the cold water container (with two cold ceramic plates at the bottom) and a candle to heat the two hot ceramic plates (two Peltier elements next to each other). In order to distribute the heat from the candle flame more evenly I will use an aluminium plate glued to the hot ceramic plates. (See the photos and the drawing in the attached photo montage.)

Greetings, Conrad

(I will travel for a week, therefore no more progress for at least a week.)
Title: Re: Thermoelectric generator - candle and cold water
Post by: Magluvin on August 18, 2012, 02:55:46 AM
Hey Conrad and TK

I havnt seen oil used with these yet.  I think a nice slug of aluminum with many thin fins, and a glob of heat sink compound does very well. These things ar not very thick from hot side to cold side. The edges are filled with silicone it looks like, white, maybe high temp, and looks just to keep the weather out from the matrix inside.

Literally if you put power to a naked chip, do not have your fingers on either side, because things happen fast. Ive only done it in short bursts and you can feel it happen, one side cold, and one hot. Its a strange experience, as it is not a common one.

I saw a vid where with a naked chip, frost develops on the cold side fairly quick.

Conrad

Maybe you could get 2 PC cpu heat sinks to help get rid of the heat in the water.

Use a dremel, or a jigsaw with a fin laminate blade and cut a square hole in the side of your  plastic water tube. Use on cpu heat sink with fins inside the tube with the water, with the flat mounting side of the heat sink facing out and seal it into the tube with silicone well to avoid leaks. So the tighter the heat sink fits in the cut out of the tube, the better mounting adn sealing will be. Then apply some heat sink compound to the flat surfaces of the mounted heat sink  and figure a way to mount the outer heat sink to that surface. 

Or use an aluminum water container. Preferably square with flat sides that cpu heat sinks can be mounted.

Or, you can just use the heat sink alone on the cold side of the chip. it is the end result in the end. ;] Heat into the air.

Any fan will make a difference in getting rid of the heat from the sink fins. More is better.

I used an aluminum block, 2.5x2.5x3/4 in between the hot side and its heat sink for the SS A/C unit, as a buffer of sorts, to give a larger volume of aluminum to absorb heat from the hot side. Ill post some pics tomorrow.

So my setup, as an AC unit, is running backwards compared to your gen. And the water is your aluminum block. ;]   It might be best to put a small heat sink on the side of the chip thats in the water, giving more surface area 'to the water'. ;]  Chip surface area < heat sink fin surface area.

MaGs



Title: Re: Thermoelectric generator - candle and cold water
Post by: Tito L. Oracion on August 18, 2012, 03:58:00 AM
 ;D


This is interesting though old but really interesting.  ;D


i will try putting the cold side in a cooler so that cold will last longer.  ;)


and i will try the iron that heats very long. and since heat is transferable then we can make it more stronger device. hmmmmm  8)
  :D


This is more efficient if we add some transistors and diode. hmmmmm  :o


I salute you contrad   :-* 


I think it much more better if we add some salt in the cooler to add extra cool.  8)   8)   8)   8)   8) 
I think liquid nitrogen can be also but  :o  lol

Do you know that to make heat, we only need two dissimilar metal  :o , why?, it acts like a battery then put some resistor. ok to prove it , try shorting the two hands of a battery wright? ;)


 ;D
Title: Re: Thermoelectric generator - candle and cold water
Post by: Magluvin on August 18, 2012, 08:21:59 AM
;D


This is interesting though old but really interesting.  ;D


i will try putting the cold side in a cooler so that cold will last longer.  ;)


and i will try the iron that heats very long. and since heat is transferable then we can make it more stronger device. hmmmmm  8)
  :D


This is more efficient if we add some transistors and diode. hmmmmm  :o


I salute you contrad   :-* 


I think it much more better if we add some salt in the cooler to add extra cool.  8)   8)   8)   8)   8) 
I think liquid nitrogen can be also but  :o  lol

Do you know that to make heat, we only need two dissimilar metal  :o , why?, it acts like a battery then put some resistor. ok to prove it , try shorting the two hands of a battery wright? ;)


 ;D

From what I understand, the chips/module cant be driven too hard with higher voltages than around 16v. Im reading about them more as i found them also being discussed in one of my power supply builder books, Regulated Power Supplies  by Gottlieb.  They can be used to help keep PS transistors cool. They use them in microprocessor cooling also.

great book. Even discusses magnet biased cores. ;]  If you pulse the primary of a magnet biased core in one polarity and measure the input/output, then reverse the pulse polarity and remeasure, one way causes more input and more output, and the other causes less input and less output. ;] or instead of reversing the pulse polarity, you can reverse the bias magnet polarity. The difference in in/out depending on polarities is caused by saturation effects, affected by the magnet in the core. ;]



MaGs
Title: Re: Thermoelectric generator - candle and cold water
Post by: TinselKoala on August 18, 2012, 08:48:45 AM
Yep. I used that latter effect to improve the output of my early Steorn Orbo replication, Orbette. The only toroids I could find at the time were long cylinders instead of rings, and when I used biasing magnets of the right polarity, the thing really sang, without any increase in applied power. Well, it was a pulse motor of type 3, a core effect motor, so biasing the core makes great sense in that design.
It's also very interesting to play with a strong NdB around the toroid of a Joule Thief.
Title: Re: Thermoelectric generator - candle and cold water
Post by: Tito L. Oracion on August 18, 2012, 08:52:23 AM
i think 30v is permissible for other chips and that is enough for us.  ;)
Title: Re: Thermoelectric generator - candle and cold water
Post by: Magluvin on August 18, 2012, 09:08:57 AM
Have you ever seen my "orbonbon' ? lol  It is a solid state orbo. The first actually.

I named it all funky because of the way you named the orbette. It was just the thing to do at the time. ;]

I have a long ferrite toroid, the kind that is used as suppressor on computer monitor cables, wound as a long toroid, neatness inside was critical because magnets go inside, and I have a pickup winding wound around the diameter.  We insert the stack of 1/4x1/8in neos on the core. The N and S poles are attracted to the core, so most of the flux is in the core and within the inner side of the pickup coil.

When we energize the toroidal winding, the core goes into the Orbo effect, and the magnets field is released, and their lines of force cross the pickup coil causing current to flow. Then when we release the toroid coil power, the flux crosses the pick up again causing current in the opposite direction.

This is as a whole is inserted into a larger set of toroids as seen in the vid to contain the expanded field of the mags beyond the pickup coil when the orbo effect is engaged. So the flux switches back and forth from the inner core to the outer core, and generating currents in the pickup along the way.  ;]

I have several vids on it. This was the last one I did.

http://www.youtube.com/watch?v=KSgGFzfDiYE&list=UUjjcpZL8tkpn4WGkU2y_lPQ&index=10&feature=plcp

MaGs

Title: Re: Thermoelectric generator - candle and cold water
Post by: Magluvin on August 18, 2012, 09:49:41 AM
Ok, just watched my vid, its been a while, and this vid doesnt use the outer core. The previous vids to that do.  It works wither way.  there were reasons for and not.

MaGs
Title: Re: Thermoelectric generator - candle and cold water
Post by: anandml on August 19, 2012, 03:57:13 AM
How to make thermoelectric generator without thermocouple module or peltier cooler I mean direct conversion of heat in to electricity with some material parts
Title: Re: Thermoelectric generator - candle and cold water
Post by: Magluvin on August 19, 2012, 04:17:03 AM
Anan, do you mean you want to make your own module instead of buying one? They are not expensive.  ;]


Here is a pic of the SS A/C unit.

MaGs
Title: Re: Thermoelectric generator - candle and cold water
Post by: Pirate88179 on August 19, 2012, 04:19:34 AM
I used to see those modules in surplus places all the time for a decent price.  I have not seen any for a while now.  Do you have a good source Mags?

Bill
Title: Re: Thermoelectric generator - candle and cold water
Post by: Magluvin on August 19, 2012, 04:35:39 AM
Hey Bill

These are larger than the one I have. I remeasured the current of the module I have and it is 3 amps not what I said earlier. Had not fired it up in a while. ;]  These are 6amp.

http://www.ebay.com/itm/2x-TEC1-12706-91-2W-TEC-Thermoelectric-Cooler-Peltier-/150471454617?pt=LH_DefaultDomain_0&hash=item2308cc2f99

The same in bulk, just a bit cheaper.

http://www.ebay.com/itm/New-10pcs-91-2W-TEC-Thermoelectric-Cooler-Peltier-12V-/160405697916?pt=LH_DefaultDomain_0&hash=item2558ecb57c

And here is a big boy. ;] 400 watt up to 26 amps

http://www.ebay.com/itm/USA-MOST-POWERFUL-50mm-TEC-on-EBAY-400W-Thermoelectric-Peltier-Cooler-TEC-12V-/310420685918?pt=US_CPU_Fans_Heatsinks&hash=item484683c45e

Im sure there are many sources out there. 

MaGs


Title: Re: Thermoelectric generator - candle and cold water
Post by: Magluvin on August 19, 2012, 04:46:15 AM
Here is a bad example on ebay. It apears to be 1 module, for just over $1k   :o And they probably occasionally hook a sucker on that too. ;]

http://www.ebay.com/itm/158w-Watt-Peltier-Cooler-Thermoelectric-Cooler-Heater-/120783133726?pt=LH_DefaultDomain_0&hash=item1c1f3c5c1e

Mags
Title: Re: Thermoelectric generator - candle and cold water
Post by: Pirate88179 on August 19, 2012, 05:20:35 AM
Mags, thank you for the links.

Bill
Title: Re: Thermoelectric generator - candle and cold water
Post by: WilbyInebriated on August 19, 2012, 07:11:47 AM
hey bill, good to see you around...

www.tegpower.com is another option.  interesting side note regarding them; when i watch their youtube videos, that guy sounds an awful lot like a certain dr. stiffler...
Title: Re: Thermoelectric generator - candle and cold water
Post by: Pirate88179 on August 19, 2012, 07:24:26 AM
Wilby:

Thanks for the link.  Yes, he does sound like the good Dr....ha ha.

Good to see you too.  I hope all is well with you.

Bill
Title: Re: Thermoelectric generator - candle and cold water
Post by: Pirate88179 on August 19, 2012, 07:45:18 AM
I ordered the 400 watt  device from the link that Mags posted above.  This should be fun to play with.

Bill
Title: Re: Thermoelectric generator - candle and cold water
Post by: conradelektro on August 27, 2012, 05:05:01 PM
I built a second thermogenerator with the two Peltier elements I had from my first build.

Two such elements http://uk.farnell.com/multicomp/mcpe-127-10-13/peltier-cooler-38-1w/dp/1639751 (http://uk.farnell.com/multicomp/mcpe-127-10-13/peltier-cooler-38-1w/dp/1639751)

The output is not better than with my first try (see at the beginning of this thread), it is about 80 mA at 1,3 Volt (about 0,1 Watt) with two candles. I tested and measured the thermogenerator with a Joule Thief circuit driving a 1 Watt 220 Volt Led bulb.

The cold water container holds about 2,5 Liters (evacuation tube with a diameter of about 110 mm, length about 320 mm.

See the attached photos. To go any further I have to order bigger elements which are capable of handling higher temperatures of up to 250 Centrigrades.

Greetings, Conrad
Title: Re: Thermoelectric generator - candle and cold water
Post by: Magluvin on August 27, 2012, 11:44:36 PM
I built a second thermogenerator with the two Peltier elements I had from my first build.

Two such elements http://uk.farnell.com/multicomp/mcpe-127-10-13/peltier-cooler-38-1w/dp/1639751 (http://uk.farnell.com/multicomp/mcpe-127-10-13/peltier-cooler-38-1w/dp/1639751)

The output is not better than with my first try (see at the beginning of this thread), it is about 80 mA at 1,3 Volt (about 0,1 Watt) with two candles. I tested and measured the thermogenerator with a Joule Thief circuit driving a 1 Watt 220 Volt Led bulb.

The cold water container holds about 2,5 Liters (evacuation tube with a diameter of about 110 mm, length about 320 mm.

See the attached photos. To go any further I have to order bigger elements which are capable of handling higher temperatures of up to 250 Centrigrades.

Greetings, Conrad

Hey Conrad

The 80ma 1.3v , was that on a load?

Can you show what you have there? Its hard to tell what is what other than some heat sink, water bucket and wires.  I just want to see how the heating and cooling are done here. It might be better to have the element on the side of the container, with the candle burning under fins of a heat sink, with a thin metal shield to help hold the heat in that area.  And the rising heat wont heat the water unnecessarily more than the cold side of the chip provides it. A vid i saw on YT the guy had the candle burning right under the bare chip, with a fan and sink on top.  Ill see if I can find it.

Thanks for showing

Are you using 2 chips here?  If so, the 2 chips will transfer more heat to the water, there by keeping the 'hot' side colder, thus less output.

If you just use 1, and get better results, then what you need for 2 is 2 candles. ;]

MaGs
Title: Re: Thermoelectric generator - candle and cold water
Post by: Pirate88179 on August 28, 2012, 04:51:51 AM
I received my 400 watt unit the other day.  I also got another smaller unit that has no specs I can find.  The only thing i did was hook one up to an old AA battery just for fun and...one side got really hot and the other very cold, very fast.  The 400 watt unit is rated at 12 volts input.  Probably designed for the coolers.

As soon as I get a chance, i will add some heat sinks and see what kind of power I can get from these units.  I know they are not supposed to be very efficient but, the concept is very cool.  Just another fun thing to play around with.

Bill
Title: Re: Thermoelectric generator - candle and cold water
Post by: Magluvin on August 28, 2012, 05:30:11 AM
I received my 400 watt unit the other day.  I also got another smaller unit that has no specs I can find.  The only thing i did was hook one up to an old AA battery just for fun and...one side got really hot and the other very cold, very fast.  The 400 watt unit is rated at 12 volts input.  Probably designed for the coolers.

As soon as I get a chance, i will add some heat sinks and see what kind of power I can get from these units.  I know they are not supposed to be very efficient but, the concept is very cool.  Just another fun thing to play around with.

Bill

Hey Bill

Thats a huge one.  ;]  Its like 10 times the power that mine, from a 6pak cooler. I dont know what they use those for. Big fridge.  Da Big Freeze.

I never tried a AA on one. ;] Sounds good for testing. Cuz 12v with the chip between the fingers, ya might get burned and frost bite. Seriously. Not a toy. ;]

Just be sure to have heat sinks that make contact with the whole surface of  the module. Portions that are not in contact will get very hot or cold, wasting what your trying to accomplish. ;] And maybe hurt the module with hot spots. A flat bare of copper or aluminum then ad sinks with fins.



Mags
Title: Re: Thermoelectric generator - candle and cold water
Post by: Pirate88179 on August 28, 2012, 06:15:28 AM
Mags:

Thanks.  Yes, I read not to full power the 400 watt one without sinks because it will melt the solder on the hot side pretty fast.  Do I really need to use some of that thermal paste like I read about?  The ceramic substrates are pretty flat and I can  lap the bottom of my sinks on a piece of glass with some sand paper to make very flat.  It seems like overkill to me to use the paste but...if I need it, I will find some.

I did notice that on the big one, the side between the ceramic plates are sealed with a ceramic cement.  On my lower powered one, they are open.  I don't guess these are waterproof to any extent are they?  I was thinking of sealing the open one up with some high temp silicone but...I don't know.

I am just fascinated by these things.  It is a great example of how nature works: Put voltage in, get hot one one side, cold on the other.  Put hot on one side, cold on the other, get electricity out.  Beautiful.

Bill
Title: Re: Thermoelectric generator - candle and cold water
Post by: Magluvin on August 28, 2012, 07:28:03 AM
Hey Bill

YES absolutely use the silicone compound.  Imagine looking under a microscope at the surfaces. It is used on transistors to transfer heat to the sink. Without, the transistor wont survive full power ratings. its all about getting the heat away from the component.
In our case, one side is all about getting it 'evenly' hot, and keeping the other side evenly cold, for best results. These things conduct heat well, considering the contrary belief once you feel the 2 surfaces while being powered.  ;] So heating one side, the other side gets just as hot. If we dont provide the best path for the heat to be absorbed from the 'cold' side, eff will go down. So its best to do your best.  ;] Use the compound. ;]

RS has some thin liquidy stuff that I dont care for much. Maybe they have something better now. Best to get some online. You will need a bit. Or if you have a local parts distributor. We had Vance Baldwin here, but not any more. I dont know if Alpha Electronics is still around. We have a cb/ham radio shop that carries some unusual parts. So maybe where you are there are distributors. Electronics repair shops in larger cities have places to go to get parts directly. I know some order all parts.  Just tryin to give ideas as to get things locally. ;]

My approach would be to use a large aluminum block on the cold side with fins as many as possible. This will ensure a consistent colder temp for the cold side. A small heat sink on the cold side wil get very warm from the candle powered hot side, even with a fan. So more bulk and fins will keep it cool to generate the best output.

The hot side, fed by candle, maybe not so big block, but a  cupped heat catch, even insulated with auto parts store fiberglass wrap for headers to help keep it hot as not to lose heat anywhere other than the Peltier module.  Theres lots that we can do to increase efficiency.  ;]

MaGs

Title: Re: Thermoelectric generator - candle and cold water
Post by: conradelektro on August 28, 2012, 09:42:06 AM
Hey Conrad

The 80ma 1.3v , was that on a load?

Can you show what you have there? Its hard to tell what is what other than some heat sink, water bucket and wires.  I just want to see how the heating and cooling are done here. It might be better to have the element on the side of the container, with the candle burning under fins of a heat sink, with a thin metal shield to help hold the heat in that area.  And the rising heat wont heat the water unnecessarily more than the cold side of the chip provides it. A vid i saw on YT the guy had the candle burning right under the bare chip, with a fan and sink on top.  Ill see if I can find it.

Thanks for showing

Are you using 2 chips here?  If so, the 2 chips will transfer more heat to the water, there by keeping the 'hot' side colder, thus less output.

If you just use 1, and get better results, then what you need for 2 is 2 candles. ;]

MaGs

The 80ma 1.3v were measured on a load. The load was a Joule Thief.

The short circuit current is a bit more, about 100 mA. Open circuit Voltage (10 Mega Ohm Voltmeter) goes up to 2.8 Volt (1.4 Volt per element).

I attach some photos showing the construction around the two Peltier elements.

It is difficult to come up with a good solution to hold the heat sink (on the cold side) and the heat distribution means (hot side, flame of the candle should not touch the ceramic) against the ceramic plates of the Peltier element. A good heat resistant glue seems to be necessary. Some use 0,8 mm copper plates as spacers (but that also needs a glue).

My "heat sink" and my "heat distribution means" are both aluminium plates 60 mm x 30 mm x 4 mm, because the Peltier elements are 30 mm x 30 mm and are located next to each other.

I need two candles in order to generate enough heat.

There is an important difference between Peltier elements for cooling and for electricity generation.

- cooling element: max temperature allowed on the hot side is around 100° Centigrade, max effective temperature difference between hot and cold side about 70° Centigrade, plastic isolation is useful because it keeps moisture away from the metals

- generator element: max temperature on the hot side at least 200° Centigrade (there are elements for much higher temperatures like 1000° Centigrade), temperature difference between hot and cold side as high as possible, plastic isolation is a bad idea because it will melt

Greetings, Conrad
Title: Re: Thermoelectric generator - candle and cold water
Post by: wizkycho on August 28, 2012, 11:18:49 AM
     Peltier is not overunity element. it means it has efficiency lower then 100% actually only 10-20%,
the best ones only 50% (but made only experimentaly, not available on market yet).
So what are you trying to do with these ? heat the house.
This ain't gona work because if you use current from peltier and connect it to some heater
peltier will apparently cool down his hot side and the current from it will dimminish.
Unless you eventually cool down cold side of peltier to temperatures colder then air or earth.
And that would take lot a energy !!!
This is not working not even in space on -273
   Guy is trying to sell peltiers this way or just yet hasen't realized that this is dead end for FE and OU.
 
think of it this way: Peltier element is very poor thermal isolator.
or - if it would be better isolator it wouldn't give of electric current
 
Igor Knitel
Perihelion Labs
 
Title: Re: Thermoelectric generator - candle and cold water
Post by: conradelektro on August 28, 2012, 04:40:26 PM
     Peltier is not overunity element. it means it has efficiency lower then 100% actually only 10-20%,
the best ones only 50% (but made only experimentaly, not available on market yet).
So what are you trying to do with these ? heat the house.
This ain't gona work because if you use current from peltier and connect it to some heater
peltier will apparently cool down his hot side and the current from it will dimminish.
Unless you eventually cool down cold side of peltier to temperatures colder then air or earth.
And that would take lot a energy !!!
This is not working not even in space on -273
   Guy is trying to sell peltiers this way or just yet hasen't realized that this is dead end for FE and OU.
 
think of it this way: Peltier element is very poor thermal isolator.
or - if it would be better isolator it wouldn't give of electric current
 
Igor Knitel
Perihelion Labs

Yes, I know, Peltier elements are definitely not OU.

The idea is to use waste heat (although the efficiency is very low). The heat would be wasted any way.

I want to come up with a good design, which can be done at home (without fancy tools).

In winter I heat my house with a conventional wood stove and I want to use some of the heat from the stove to create electricity. This is not new, there is no invention, may be there will be a nice design. The idea to use part of the heat from the stove to charge a battery pleases me. It is probably not very useful and by no means a replacement of my connection to the electricity grid.

I do not sell anything, my experiments are for my personal education and enjoyment.

I posted my contraption under Conventional alternative energy systems (http://www.overunity.com/collapse/c/5/sa/collapse/f28240f/9c652a85488af34984eef6cc1225c5f7/#c5) and there in All other conventional alternative energy creation systems. (http://www.overunity.com/all-other-conventional-alternative-energy-creation-systems/)

So, it should be clear, it is a conventional system for energy creation.

My contraption is "alternative" in the sense, that waste heat is rarely used. A good example for a good use is the rover Curiosity which rolls on Mars just now. In fact, the news about Curiosity inspired me to play with Peltier elements. (I will not use Plutonium for heating. I generate heat by burning wood or candles, which in itself is a bit "alternative" nowadays.)

I think it is interesting, that one can generate additional light (with a LED-lamp) when lighting candles. The waste heat from the candles is turned into electricity by the Peltier elements. (And one has the light from the candles as well.) Yes, not very exciting, no business opportunities, but nice nevertheless.

Greetings, Conrad
Title: Re: Thermoelectric generator - candle and cold water
Post by: Pirate88179 on August 29, 2012, 02:55:50 AM
Conrad:

I agree with you 100%.  No OU of course but I like the challenge of finding a way to use these where we are already paying for the hot, or the cold.  One example a buddy of mine used it for was against his cold window in the winter, and the heat from his house inside, that he paid for anyway....he could light a large led bulb via a jt circuit and it was free.  The reverse might be true in the hot summer with the ac on.

To me, this is the fun of it....trying to find out new and unique ways to apply this technology.  It is not easy as the hot and cold sides are very close together but...with some good thinking, I know folks will find some great ways to use these.

Bill
Title: Re: Thermoelectric generator - candle and cold water
Post by: DreamThinkBuild on August 29, 2012, 05:34:48 AM
Hi Conrad,

You are doing very good work. I like the idea of reclaiming heat that would've been lost anyway. In the winter you have plenty of snow to keep one side cold. :)

Maybe add a freezable cup that can be popped on and off the top. Stick a couple in the freezer, since your paying for the power already for the fridge reclaim some of that energy too. When one starts to warm down just pop it to the freezer and pop on a new frozen cup.

You could also add some solar panels and capture the light from the candles. Get high current cells, like .5vdc, 7amp cells with artificial lights you lose about 98% power. So a 7amp cell will be more like 140ma. Three panels will give you enough to charge a battery or ultra-cap to 1.5vdc.

I toyed with the idea when the power went out during the snow storm Alfred:

http://www.overunity.com/11635/pyro-photo-voltaic/

Keep experimenting. ;)
Title: Re: Thermoelectric generator - candle and cold water
Post by: Magluvin on August 29, 2012, 05:54:54 AM
Hi Conrad,

You are doing very good work. I like the idea of reclaiming heat that would've been lost anyway. In the winter you have plenty of snow to keep one side cold. :)

Maybe add a freezable cup that can be popped on and off the top. Stick a couple in the freezer, since your paying for the power already for the fridge reclaim some of that energy too. When one starts to warm down just pop it to the freezer and pop on a new frozen cup.

You could also add some solar panels and capture the light from the candles. Get high current cells, like .5vdc, 7amp cells with artificial lights you lose about 98% power. So a 7amp cell will be more like 140ma. Three panels will give you enough to charge a battery or ultra-cap to 1.5vdc.

I toyed with the idea when the power went out during the snow storm Alfred:

http://www.overunity.com/11635/pyro-photo-voltaic/ (http://www.overunity.com/11635/pyro-photo-voltaic/)

Keep experimenting. ;)

Well, solar panels work better when cool vs hot, so we could mount these on the back of the solar panel(hot side), and the cold side could transfer the heat to water pipe system for producing hot water.

So now our solar cells work better, we also get power from the Peltier's and hot water to boot. All in the same square area. ;] Just a little thicker. ;]

MaGs
Title: Re: Thermoelectric generator - candle and cold water
Post by: Pirate88179 on August 29, 2012, 06:18:51 AM
Mags:

Exactly the type of thing I was talking about.  I saw a tube video last night where a guy had a 300 watt peltier and ran it from a computer power supply.....the cold side made a large blob of water into ice in less than 36 seconds.  That has to be useful somehow.

Bill
Title: Re: Thermoelectric generator - candle and cold water
Post by: Magluvin on August 29, 2012, 06:34:55 AM
Like a microwave ice maker. ;]  Quickice.  Nestley IceQuick  ;]

MaGs
Title: Re: Thermoelectric generator - candle and cold water
Post by: twinbeard on August 29, 2012, 06:56:07 AM
You guys are totally on the right track with using these to cool down photovoltaic, then move the heat away in water pipes.  I came here to recommend that, but you guys are already thinking correctly:)
Title: Re: Thermoelectric generator - candle and cold water
Post by: Pirate88179 on August 29, 2012, 07:09:45 AM
Twinbeard:

ARRRR...good to see you again.  I believe there are many new uses we can find for these things.  I just watched a vid on the tube where a guy charged his cell phone while camping using the campfire and some cold river water.  As mentioned by someone above, not efficient but, it got the job done when nothing else would.  Even works at night or on a cloudy day.

Bill
Title: Re: Thermoelectric generator - candle and cold water
Post by: Magluvin on August 29, 2012, 07:12:37 AM
Well, solar panels work better when cool vs hot, so we could mount these on the back of the solar panel(hot side), and the cold side could transfer the heat to water pipe system for producing hot water.

So now our solar cells work better, we also get power from the Peltier's and hot water to boot. All in the same square area. ;] Just a little thicker. ;]

MaGs

Lol, then we can take the power stored from the peltiers, power that we collected heating water, for free, ;] , then use that stored power to pump the water in cycles. So now we have a solar panel, that heats water, not using the power from the solar panel to do so, and we get water cycling energy from the peltiers.

Just trying to think of a logical use for that energy. Sounds like a marketable combo system, while increasing the solar panel efficiency as a plus, plus.  ;]

maGs

 
Title: Re: Thermoelectric generator - candle and cold water
Post by: Magluvin on August 29, 2012, 07:25:10 AM
Twinbeard:

ARRRR...good to see you again.  I believe there are many new uses we can find for these things.  I just watched a vid on the tube where a guy charged his cell phone while camping using the campfire and some cold river water.  As mentioned by someone above, not efficient but, it got the job done when nothing else would.  Even works at night or on a cloudy day.

Bill

Son, go out and chop some logs for the fire, I think we will run the A/C tonight. ;]

Use the fire to generate, to run a peltier A/C unit.

That 400w jobby, I bet would blow some really cold air with the right combination of heat sinks and blowers. My little 40w produces some cold air. That 1 400w module could probably surprise you.  My buddy want to try to make an ac for his elcamino. We have to test larger or multiples to see what happens. The peltiers are not expensive to play with.

MaGs
Title: Re: Thermoelectric generator - candle and cold water
Post by: conradelektro on August 29, 2012, 09:32:22 AM
I am very happy with the many ideas presented in this thread.

Pirate: cold window. I have a "cold window" next to both of my stoves (see photo). Some Peltier elements with the cold side against the window and hot water or steam from a kettle through some pipes to a heat exchanger on the hot side of the Peltier elements. Have to think about the heat exchanger (where to salvage it from) ? Since I do not want to glue something against the three glass windows, the whole thing should only lean against the cold window.

DreamThinkBuild: I should have found your Pyro Photo-Voltaic thread in order to use it, sorry. The idea with the frozen cup works here in winter by just putting it outside in the freezing weather for an hour. Good idea to use solar cells in combination with the candles. Are there solar cells that like infra red as a light source? I guess the solar cells rather lean towards ultra violet light?

Magluvin: Yes, that is right, Peltier elements on the back side of solar panels. Wood: around here you could get broken down trees for free as long as you remove them from the woods by your self. A lot of work, a few liters of gas for the transport, but almost for free. A friend of mine gets the cut off (mostly bark) from a saw mill for free. He just has to collect this low grade wood. He cuts it and uses it for his stoves. Again, some work, but his heating is cheap. When I was a kid, people used to cut down bushes and make brushwood bundles for the kitchen stove. All this will come back with the shrinking world economy.

I ordered four 40 mm x 40 mm Peltier elements sustaining 200° Centigrade from eBay. There are better ones, but they cost more. For a home project it would not matter to use a few more as long as they are cheaper than the high power stuff. Once we have a good and practical design, it might be worth to get some really good ones for about 60.-- Euro each (60 mm x 60 mm, 250° Centigrade).

I will also get some heat resistant and heat conducting paste and some heat resistant and heat conducting glue (a bit expensive).

Is it better to press the heat exchanger against the Peltier element? If yes, it is not so easy to come up with a design that does not heat the cold side as well. Something has to press against the hot side and the cold side and this something will conduct heat away from the hot side and heat to the cold side via a support structure.

How strong is the Peltier element mechanically? The ceramic plates seem to be brittle and gluing something onto them seems to be the only good way. The brackets I built do not seem to work very well. The brackets can not grip well because the space in between the ceramic plates where the metals are is very limited (short circuit has to be avoided, only one ceramic plate should be touched by the bracket).

As some said, it is not straight forward to build something good and practical around a Peltier element, and it becomes more difficult in case one wants to combine a lot of elements. Glue, paste and heat exchangers pressed against the element seem to be the standard design choices. There are elements that support open flames at 1000° Centigrade (of course they are expensive).

Greetings, Conrad
Title: Re: Thermoelectric generator - candle and cold water
Post by: wizkycho on August 29, 2012, 02:42:02 PM
Conrad:

I agree with you 100%.  No OU of course but I like the challenge of finding a way to use these where we are already paying for the hot, or the cold.  One example a buddy of mine used it for was against his cold window in the winter, and the heat from his house inside, that he paid for anyway....he could light a large led bulb via a jt circuit and it was free.  The reverse might be true in the hot summer with the ac on.

To me, this is the fun of it....trying to find out new and unique ways to apply this technology.  It is not easy as the hot and cold sides are very close together but...with some good thinking, I know folks will find some great ways to use these.

Bill
1. burning choped trees, oil, gas, coal, using freones, even OVERIDIOTIC nuclear power... is somewhat nice (except latest) and brought us where we are now, but it is not affordable anymore cause it does massive damage to ultra thin atmosfere layer.
 
from political aspect and a plot of it - it is just not civilized, THA MAN has to have unquestionable (money fearless) right on food, air, drinking water, living space, heat in winter, shade in summer ...as
long ...one becomes MEGALOMANIAC (in any way - money ,rule power , control over other THA MAN, OVERwelth ... etc.))
THA MAN allways knows the neccesity of those unquestionable things - by natural experience - by pure mother physics, by pure existance. (doesn't have to be induced by anyone).
because there IS meassure, there IS shape , there IS light ...
MEGALOMANIACS es OVERMONEY and OVERCONTROL have ultra hazy effect on THA MAN and MEGALOMANIACS must be dragged back to it's boundaries and real humanoid meassurements.
OVERUNITY is their CURE and WE GOT TO TAKE THE POWER BACK there is much at stake.
I am COMUNIST (updated on v2) and whole universe and everything (even everyone) in it is COMUNISTIC, because there IS meassure, there IS shape , there IS light, there are GODS rules everyone must follow.
Christianity and Communism are same thing. kapitalism is meere destruction and violence                          (this is ultra close to the truth)
 
Keep up good research causemany todays devices sadly haven't been updated (exp. Refrigerators nad coolers - Magnet Gadolinium interaction ...)
although more efficient, durable and less harmfull technologies exists.
Maybe you could try to use gadolinium in cooling peltier.
... but as things looks today, (hope I'm wrong), preferably choose solving first "issue".
 
wiz
Title: Re: Thermoelectric generator - candle and cold water
Post by: wings on August 29, 2012, 11:13:22 PM
now closed  >:(  but
using wayback machine:


http://web.archive.org/web/20060928004514/http://www.varmaraf.is/engl/prod.htm (http://web.archive.org/web/20060928004514/http://www.varmaraf.is/engl/prod.htm)

http://solar-club.web.cern.ch/solar-club/solpv/autres/thermoPV.html

see also:


http://www.globalte.com/index.php?pageId=2&sId=31 (http://www.globalte.com/index.php?pageId=2&sId=31)
http://www.azonano.com/article.aspx?ArticleID=1685 (http://www.azonano.com/article.aspx?ArticleID=1685)
Title: Re: Thermoelectric generator - candle and cold water
Post by: conradelektro on August 30, 2012, 09:11:10 AM
@wings:  thank you for the very interesting links.

May be someone knows this:

Many Peltier element specifications mention a maximum useful temperature difference of about 70° Centigrade.

Is this a limit for all Peltier elements? (A limit for the Seebeck effect?)

Many Peltier elements can operate at high temperatures, e.g. 200° or 1000" Centigrade. But at this high temperatures, does the limit of "70° temperature difference" still apply?

This would mean, if a Peltier element is operated at e.g. 200° Centigrade, it would not help (as far as efficiency is concerned) to keep the cold side at a lower temperature than 130° Centigrade?

Greetings, Conrad
Title: Re: Thermoelectric generator - candle and cold water
Post by: wings on August 30, 2012, 12:11:09 PM
@wings:  thank you for the very interesting links.

May be someone knows this:

Many Peltier element specifications mention a maximum useful temperature difference of about 70° Centigrade.

Is this a limit for all Peltier elements? (A limit for the Seebeck effect?)

Many Peltier elements can operate at high temperatures, e.g. 200° or 1000" Centigrade. But at this high temperatures, does the limit of "70° temperature difference" still apply?

This would mean, if a Peltier element is operated at e.g. 200° Centigrade, it would not help (as far as efficiency is concerned) to keep the cold side at a lower temperature than 130° Centigrade?

Greetings, Conrad

I am not expert in this field but IMO the standard Peltier modules have 70° -75° maximum difference for cooling purpose (you apply current and the max temperature difference is 70°- 75°).
http://crystalltherm.com/thermomodules_s.html (http://crystalltherm.com/thermomodules_s.html)

The generator type have no reference to differential temperature.
http://crystalltherm.com/powergenerating.html (http://crystalltherm.com/powergenerating.html)

The maximum operating temperature 200° is related to the production process and in particular to the solder

http://crystalltherm.com/downloads/Products_Catalogue_2011.pdf (http://crystalltherm.com/downloads/Products_Catalogue_2011.pdf)
http://crystalltherm.com/downloads/New%20Modules%20Assembling%20Technology%20by%20Crystal%20Ltd.pdf (http://crystalltherm.com/downloads/New%20Modules%20Assembling%20Technology%20by%20Crystal%20Ltd.pdf)


600°down to 50° - 678w
http://tes-ne.com/PDF/Panel%20E%20ACPACPO.pdf


the old style use direct gas flame
http://www.douglas-self.com/MUSEUM/POWER/thermoelectric/thermoelectric.htm (http://www.douglas-self.com/MUSEUM/POWER/thermoelectric/thermoelectric.htm)

new from BMW and other
http://green.autoblog.com/2008/08/11/researchers-work-to-turn-cars-exhaust-into-power/ (http://green.autoblog.com/2008/08/11/researchers-work-to-turn-cars-exhaust-into-power/)
http://www.tellurex.com/products/tPOD1.php (http://www.tellurex.com/products/tPOD1.php)
http://tes-ne.com/English/01_home_e.html (http://www.tuaw.com/2011/06/14/hatsuden-nabe-thermoelectric-cookpot-keeps-your-iphone-battery-c/)





 
Title: Re: Thermoelectric generator - candle and cold water
Post by: conradelektro on August 30, 2012, 02:49:14 PM
@wings: again, nice links, I particularly like the lamp charger http://www.tellurex.com/products/tPOD1.php (http://www.tellurex.com/products/tPOD1.php)

I did some more experiments with my candle light based on a cold water container and two Peltier elements (see the photos).

I measured the Voltage and current draw under load when driving a Joule Thief which in turn lights a 1W 220 V LED bulb:

initially: 1,5Volt - 140 mA --> ~ 0,2 Watt

after 10 minutes: 1,3 Volt - 100 mA --> ~ 0,13 Watt

Why did the output drop? After some useless tinkering I stirred the cold water in the container with a spoon, and the output went up again to about 0,2 Watt. I could do this cycle several times.

I seems my contraption has a severe problem with heat dissipation from the two Peltier elements (cold side) into the water. When stirring the heat is transported away more efficiently, therefore more output.

I studied a bit the various manufacturer web sites (e.g. as provided by Wings, see http://www.customthermoelectric.com/TEG_install.html (http://www.customthermoelectric.com/TEG_install.html)) and now I think one has to do the following:

- there has to be a certain pressure between the cooling/heating plate and the ceramic plates of the Peltier element in order to increase heat transfer

- some filler (thermal interface material) between ceramic plates and cooling/heating plate is necessary, again to increase heat transfer

I ordered some heat transfer paste (copper based) and have to come up with a design that allows to press the cooling / heating plate against the ceramic plates of the Peltier element. Have to look for a good heat isolation material.

People starting with experiments should take this into consideration.

(Of course, this was all known for a long time, but I did not know it. And therefore my contraption has such a poor output.)

Greetings, Conrad
Title: Re: Thermoelectric generator - candle and cold water
Post by: conradelektro on September 28, 2012, 09:29:24 PM
I built a new version of my candle power generator. See the photos.

There is only one Peltier element TG127-250-37h , dimensions 50 x 50 x 4 mm.

The output is a bit disappointing: 0,89 Volt at 30 mA = 0,027 Watt , loaded with a Joule Thief type circuit driving a 1 Watt 110 V - 220 V Led lamp.

The LED lamp shines o.k. , but of course not with full brightness.

There is a copper particle paste between the aluminium parts and the Peltier Element and the aluminium parts are pressed against the Peltier element. But in spite of this effort, the output is meager.

The Peltier element has a high rating: 12 Watt at a temperature difference of 200 Kelvin. I guess I do not reach this temperature difference and can not transport the heat efficiently.

I found a good isolation material: http://en.wikipedia.org/wiki/Vermiculite (http://en.wikipedia.org/wiki/Vermiculite) (used in stoves instead of fireclay, looks like fiber board and can be sawed like wood)

Some  more thinking necessary.

Greetings, Conrad
Title: Re: Thermoelectric generator - candle and cold water
Post by: Magluvin on September 29, 2012, 01:27:10 AM
Try some ice in the water 50/50 and try the candle direct to the chip surface. maybe aluminum foil stuck to the chip surface with thin layer of compound to stick it, this way the chip doesnt get blackened.  Imagine how hot the hot side is and the cold side is when you apply 12v to the wires. Thats the kind of temp difference you want to create to generate. Just some thoughts.

Mags