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Author Topic: 25mV Joule Thief powered by peltier merely using our body heat -Free energy 24/7  (Read 302169 times)

wings

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regarding light power

..... the led has 10 times the efficiency of the candle ....

http://www.youtube.com/watch?v=0_GqE5aDR68


http://www.buytpod.com/


http://www.tellurex.com/products/power.php





conradelektro

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@wings: It is of course well known to use Peltier Elements as a power source (in combination with fire).

I did some experiments, see http://www.overunity.com/12607/thermoelectric-generator-candle-and-cold-water/#.UPU9BGckQfw .

Usually one needs a big temperature difference (e.g. 100° Celsius, better more) between hot and cold side to draw some useful energy from a Peltier Element.

The new (and for me interesting) feature of magpwr's circuit (and the discovery of the 2SK170 transistor) is the fact, that very small temperature differences (e.g. 10° Celsius) can make a LED glow with a Peltier Element.


Eventually it could be interesting to charge a small 1.2 Volt accumulator with a small temperature difference (without fire, just natural temperature differences e.g. between water and air, or air and ground). Not a world saving thing, but nice.

And in itself, it is interesting, that one can make a LED glow starting with about 50 mV. The big event (for me) is the discovery of the 2SK170 for the Joule Thief type circuits, bringing the Voltage down to 50 mV (which I never saw before magpwr's disclosure).

Greetings, Conrad

magpwr

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Hi Wings ,conradelektro,

Thanks for showing me the thin film peltier  i have done research on this thinfilm version around 1 or 2 years but didn't know where to buy those.Maybe at that time it was just at discovery stage.

Thin-film peltiers
http://www.nextreme.com/

I will not use buy those thin film peltier yet unless i'm focus on making circuit and everything else tiny. 

My next investigation  might or might not be "overunity" which remain to be seen/tested yet.This is what i have in mind base on an old discovery which i accidentally discovered around 4 or 5 years ago.

This is my long story short how i accidentally discoverd something of interest-
You see i love upgrading pc along with graphics card once every 2 years since i love playing games for max 2hours to keep my mind\cpu working at top speed.

I wanted to try a different kind of cooler available in market at that time.The cpu cooler i purchased uses a liquid/gas to cool the CPU. The gas used is Tetrafluoroethane-1,1,1,2 (R134A).
Please check the link to see how the cooling effect works.
http://www.bjorn3d.com/2005/09/asetek-vapochill-micro-ultra-low-noise-cooler/#.UPVnXGehfng

This is my discovery i took the  "VapoChill Micro" by hand of course.Since our hand tend to be shaky a little as long as we move.
This is what i noticed by merely moving the "VapoChill Micro" a little i noticed the base of cpu cooler getting really cold and also noticed "water condensation taking place quickly at the base".

Please take note i'm living in a tropical country where the temperature remains at around 30 degree celsius throughout the year ,+- 3c difference max.
I did not have those remote temperature monitor around 5 years back.But my guess is base on speed the water condensation taking place in matter of few seconds on gas based cpu cooler might be  around 10 or 15 degree celsius cooler than my room temperature.

That's all for my discovery part.
-------------

I have an idea which might generate "overunity" if it works.If we were to place peltier beneath the gas base cpu cooler(cold) and heatsink is place one side peltier to obtain hot temperature from my room(hot).

Place the (cpu cooler with peltier with heatsink under the peltier ) onto something that it will rock this unit to and fro or left to right easily.Since we now know that this gas base cooler is  really good at "losing heat" for whatever reason.
I'd believe we some of us have seen commercial unit sold as decor or entertainment visual unit  where it just move left to right maybe with 1 battery or solar.I have no name for it at the moment.

Since we know peltier could definately generate electricity by temperature difference generated especially from rocking motion(gas cpu cooler) against my room temperature 30c.
We take that electricity from peltier to power the rocking motion coil via the 25mV joule thief.As the unit moves left to right for example gas cpu cooler gets even cooler.

This is just theory to generate electricity on infinite basis with no further human  intervention.It really depend on peltier efficiency among other thing eg:design.












 

conradelektro

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@magpwr and all OU by cooling fans:

Look at http://en.wikipedia.org/wiki/Heat_pipe , it describes the principle behind "heat pipe cooling".

About the shaking: according to my understanding, the "shaking" of a "heat pipe cooler" is a one time option. The droplets which have formed at the top of the heat pipes are shaken off and drop to the bottom, where they evaporate and cause noticeable cooling. But once all droplets have fallen, it will take a long time till they form again (at least minutes). And it does not matter whether all the droplets fall at once (by shaking) or fall off one by one (cause by gravity once they become too big for adhesion) over a longer period.

So, let's say the air flow through the cooler is such that the droplets form within 1 minute. Now, we can shake off most of the dropplets at the end of each minute by hand. Or, we can let the thing be and the droplets fall slowly over the whole minute. In both cases the dissipated heat will be about the same.

I see no OU effect. The dissipated heat depends on the air flow (e.g. Litre per Minute) through the heat sink (laminates) and on the temperature and moisture of that air.

The advantage of a heat pipe cooler (pipes in a laminate, without compressor) is that it can be smaller than a conventional heat sink (laminates, without the heat pipes). This is practical, but not OU.

Let's say we move 100 Litre of air through a conventional cooler per minute. We have to move the same 100 Litre of air through the heat pipe cooler per minute, but the air will have to move through a smaller space, which means we need a bit more fan energy, because the air has to get a higher speed (in order to press the same 100 Litre per minute through a smaller hole). So, the heat pipe cooler even needs a little bit more energy for the fan than a conventional cooler. But roughly speaking, they need the same fan energy (at a given air temperature and moisture, and cooling down to the same temperature)

The next OU hurdle is the efficiency of Peltier Elements. The best Peltier Elements have an efficiency of 7%. So, the cooler would have to be at least 15 times OU.

Having ranted against OU, I am still convinced that a "heat pipe cooler" can be a big help when using a Peltier Element, because the cooler can be smaller, which is practical. And the size difference is big. And a "heat pipe cooler" can cool down to the melting point of the working fluid (a conventional air cooler only down to air temperature).

My humble low tech design: A platform (big or small, depending on the money you want to spend) floats on a lake or river. On the platform are many Peltier Elements arranged like ceramic tiles on a floor in a horizontal plane. The hot side is above and carries big heat catching laminates through which the wind pushes the rather warm air. The cold side is below and carries a heat sink (laminates) reaching deep into the water. Water in a lake is colder the deeper one goes down, water in a river might be cold because it comes from the mountains. This works day and night, as long as the air is warmer than the water, which is the case in the area where magpwr lives. It is not so in Austria, where the air is easily cooler than the water in winter and even in spring and autumn during a cool night. But one could flip around the platform when the air is cooler than the water. Today the air is -2° Centigrades and the water in the lake is about 8° Celsius (at least 4° at the bottom). So, the flipped around platform would work.

But, I think, going for photo voltaic on the equator is the better option. The best application for Peltier Elements is a Plutonium reactor giving off heat on Mars where the air temperature is minus 90° to minus 200° Celsius (or in space). Small problem, the Plutonium could kill you at least for 50.000 years. So, please, do not experiment with Plutonium.

Greetings, Conrad

gyulasun

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Hi magpwr,

I have done some search on very low collector-emitter saturation voltage transistors and found the following type:
ZXT13N15DE6  Vcesat=5mV at Ic=100mA   and  45mV at Ic=1A  data sheet http://www.diodes.com/datasheets/ZXT13N15DE6.pdf  and available at Mouser ( http://uk.mouser.com/Search/Refine.aspx?Keyword=zxt13n15 )

Regarding the JFET types I wonder if you tested already the so-called switching or chopper type JFETs like J105, J106, J107, J108 or J109 ?  They have 3 Ohm to 18 Ohm drain source ON resistance, respectively, at zero gate source voltage.  What do you think? Their transconductance is not specified due to the switching purpose of operation but it is surely inherently pretty high.  Here are prices and data sheets: http://uk.mouser.com/Semiconductors/Discrete-Semiconductors/JFET/_/N-96ngcZscv7?Keyword=j10&FS=True  Notice that in the Vertical Column Drain Current (Idss at Vgs=0) the currents are wrong (like 0.005mA) just study the data sheets.

Regarding your idea, it sounds very interesting and as a shaking solution you may wish to consider the vibro motor of cell phones: they are tiny electric motors with an small weight fixed to the rotor shaft in eccentric position. Unfortunataly they have very high RPM (several thousand) but maybe giving them much less supply voltage could help on this. Here is what I mean:
http://tinyrc.com/qfm/racing/dls/microspec.htm   but there are many types due to the variety of mobile or cell phones or pagers.

Thanks for all the great work.

rgds, Gyula

EDIT  magpwr: I have just read through your earlier posts and noticed you already mentioned the J series of JFETS are not good (if you really meant J105 to J109 as I wrote above) and you also hinted at using vibrating motors to replace Peltier cell.  So sorry for "reinventing the wheel" LOL  that was unintentional.
« Last Edit: January 16, 2013, 12:15:16 AM by gyulasun »

magpwr

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Hi gyulasun,

It seems the 4th generation transistor link you shown me (VCEO=15V; RSAT = 29mOhms ; IC= 5A) could compete with mosfet.

But those component are smd(Surface mount version).
For testing and creating prototype it's better to use transistor that could be added and removed easy from test board.
 
 I have already tested all jfet series JXXX and all of those didn't work.I have mentioned it somewhere in my youtube channel title 25mv Joule thief.

I need to have time to work on my plans especially gas heatsink with peltier underneath, heatink under peltier as well.
If i move it by hand it should generate electricity.But i realised water could be created from condensation at the lower part of gas heatsink.
Unless peltier output is connected to joule thief to generate higher seeback which might prevent water formation from happening.Not tested yet.

gyulasun

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Hi gyulasun,

It seems the 4th generation transistor link you shown me (VCEO=15V; RSAT = 29mOhms ; IC= 5A) could compete with mosfet.

But those component are smd(Surface mount version).
For testing and creating prototype it's better to use transistor that could be added and removed easy from test board.
 
 ...

Hi magpwr,

Thanks and I agree, it is not convenient to fiddle with SMD components.  For test purposes I often used SMD component prepared with color wires of 3-4 cm long soldered to the SMD so you actually deal with or plug into the testboard the end of short wires.

In the meantime I found similar very low saturation type, seems they are manufactured in SMD nowadays.
Vceo=20V  Rsat=18mOhm   Ic=7A       http://www.mouser.com/ds/2/115/ZXTN19020CFF-77912.pdf   

Good luck with your plans on gas heatsink with Peltier underneath.

rgds,  Gyula

acmefixer

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Have you tried the J105 or TN0702 FETs for a low voltage JT?  The trick is to get it to start by itself.  I also put a 1.5V button cell in series with the gate to reduce the voltage needed to get it to conduct.  The gate draws zero current so the cell lasts almost forever.

You can get some good ideas from the schematic and information for a low voltage converter (.PDF) found here.


Hi conradelektro,

Nice work man.This is how 1st started with <100mV Joule Thief using transistor 2SD1450 (0.13v..0.3v VCE(voltage drop between emitter and collector at 400mA.By referring to datasheet and looking at vce
for expected circuit current draw.

If you refer to my youtube channel  "sanjev21" "45mV Joule Thief" was my 1st low power joule thief  using  "2SD1450" Japanese transistor.But it was not self starting and i had to manually short emitter and collector of transistor to kick start oscillation.

My other experiment which i have not posted in youtube using the best NPN transistor i could find in digikey "ZTX1048A" which have the lowest Voltage drop across emitter&collector at mere(27mV...45mV) at 500mA.Little smaller than TO92 and could handle 4Amps or 20Amps pulse no "heat sink".
Using this ultra low drop transistor i could achieve oscillation as low as "30mV" but as usual i have to kickstart oscillation at higher voltage eg:60mV by temporary shorting emitter&collector.

I have also combine ZTX1048A transistor(To boost output current) and (2SK170 or 2SK364 or 3SK366 .But take note 2SK170 do have better lower starting voltage by 1..3mV)  Junction-FET(To self start osc at low voltage).Connecting 22ohms from coil to transistor and 1.8k coil to JFET Gate while connecting (JFET Source to transistor emitter,J-FET Drain to transistor Collector).Design for <100mV.

For this above transistor and JFET combined circuit i was able to charge 1000uf cap in matter of <5sec to reach around 2volts.

But the current drain for above transistor with JFET circuit  is  around 100mA .
I was using 50FARAD 2.5v Ultra capacitor(charged with 1AA battery for few seconds to reach 100mV) as power source.Since it's known ultra cap got very low internal resistance.

The above circuit will work very nice on 1.5V battery but need to tweak 22ohms resistor to higher value to maintain current draw at decent level eg:100mA.
Then again i realised it's pointless using JFET for 1.5v battery since we could use transistor which is more efficient at higher current.

Peltier only produce <5mA if I connected to multimeter if i use my hand as heat source(36.5c) against room temperature in my case(30c for a hot country) 6.5C difference.
The peltier i'm using do have internal resistance of around 3ohms(Out of the box /Not in use).
In theory i'd believe if we use lower internal resistance for peltier <2ohms we may get better current output but then again.I 'm not sure if multi meter could properly detect "current" at such low voltage produce from peltier 70mV..90mV.

Solar cell do work to power my JFET base joule thief in room lighting or led light.I'm not sure if using other power source like from crystal radio could work.

If we match "source and circuit impedance" then we could  further optimize on efficiency.


Lastly the circuit do work on 1 x 2SK170 as well with lower Circuit current draw at 1mA using peltier at around 60mV. I used 4 JFET  since i noticed there is improvement with output voltage especially with Led as load current draw increases to 4.2mA(Mentioned in youtube description).

Lastly if anyone wish to go for extreme low starting voltage at 22mV instead of 25mV got to try 2n3972 JFET (But very low current handling in itself output capacitor cannot be more than 100nf) and combine with 2SK170 x 3 or 4.

If anyone is a expert with SMD base tiny circuits there is UK base company which manufacture 2SK170 as LSK170  (TO92 package and SMD tiny version).
http://www.micross.com/packaged-parts-plastic-discretes.aspx

conradelektro

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Have you tried the J105 or TN0702 FETs for a low voltage JT?  The trick is to get it to start by itself.  I also put a 1.5V button cell in series with the gate to reduce the voltage needed to get it to conduct.  The gate draws zero current so the cell lasts almost forever.

You can get some good ideas from the schematic and information for a low voltage converter (.PDF) found here.

@acmefixer: How good and interesting magpwr's circuit with the 2SK170 transistor is (if one has a very low Voltage power supply), can be seen from the fact that neither the circuits discussed in your blog nor the circuit from the PDF document can reach down to 25 mV. The voltage converter in the PDF-document needs at least 0.3 Volt and the circuits in your blog seem to use ordinary 1.5 Volt batteries.

I carefully verified magpwr's claim. With 4 transistors 2SK170 the circuit consumes about 2.2 mA at 50 mV (110 µW); a white LED glows nicely, of course not super bright. And one can make a LED glow by touching the hot side of a Peltier Element with the hand (the cold side at room temperature).

In case one uses only one 2SK170, the power consumption at 50 mV is about 500 µA (25 µW, the LED glows less bright)

Now, show me a circuit and a transistor which can do better (less than 50 mV supply Voltage and less than 500 µA supply current to make a white LED glow, self starting). This might not be very useful, but it is an interesting experiment.

Greetings, Conrad

magpwr

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Hi acmefixer,

It's been some time since you provided suggestion on ZTX transistors in youtube.I did purchased ZTX1048A and ZTX pnp version.
"I will be revealing a "one button" programmable code lock using pic12f629 and  using ZTX transistors in H-bridge configuration using one 1 AA battery to power gear motor. in youtube"
Once 70rpm motor arrives.The standby power is <15uA.It's a unique  circuit using only 1xAA battery to operate microprocessor and power the latch or lock example lock for drawer.


I did waste money purchasing  just 2x J105 while waiting for (10 x 2SK170)for 2USD to be delivered since the spec for JFET although it looks like it was the best N-channel JFET with lower turn on resistance.

As usual i start test using ultra cap 50 Farad charged to around 100mv using 1AA battery for 1 to 3 seconds.

I placed the JFET into same toroid with 4:100 but oscillation did not happen <100mV.

From the link you provided it looks it will work around 300mv maybe.

The circuit does needs alot of components which may increase current draw.


 

acmefixer

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@magpwr  I needed a low voltage source, so I started experimenting with a thermocouple.  I got this from an old water heater or furnace, so long ago I can't remember which.  I put it in the flame of the burner on my stove and it measured 42 millivolts.  I connected a 1 ohm resistor across it, and the DMM dropped 2 mV to 40 millivolts.  So it is capable of driving a very low resistance load.

The Joule Thief takes about 130 milliwatts and 88 milliamps at the normal 1.5V, and much more current at lower voltage if you want the LED to be lit to its full brightness of 20 milliamps.  So getting a Joule Thief to run at less than 1/2 volt is a very difficult and challenging project.  I think that it would be much, much better to put several peltiers or thermocouples in series to get at least a few hundred millivolts, so that the Joule Thief doesn't have to use power MOSFETs in parallel to get the power the LED needs.  I also think that working at 40 millivolts from the thermocouple is just a really big problem, since even the shortest leads of the components can have tens of millivolts drop at high currents.

You're going to have to find out this for yourself.  I know from my experiments at a half volt from a single solar cell.  Best of success, and good luck.

gyulasun

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Hi Folks,

I found a Lin Tech "energy harvesting" product line for solar, Peltier/Thermoelectric  and Piezo electric voltage sources and they work as DC-DC converters.
Here is the full family:  http://parametric.linear.com/Energy_Harvesting   and this is an IC able to start and operate from already 20mV DC difference:  http://www.linear.com/product/LTC3108   it produces 4 different DC outputs between 2.35V to 5V.

Its working principle is that the minimum 20mV DC input feeds a step up transformer and an inner switch chops up the DC input via the primary of the transformer and the up-transformed pulses at the secondary of the transformer is tuned to resonance by outside capacitors and this AC is rectified and taken care of by the built-in circuits.  An interesting solution.  Digikey, Farnell or others have it.

rgds, Gyula

magpwr

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Hi  gyulasun,

I'm did research on LTC3108 previously.

But the key component looks like too tiny for me to work on.Besides it needs more discrete component eg:capacitor.

But price of component for my 25mV joule Thief likely below < 8USD and the efficiency could be comparable with LTC3108.

The efficiency is not tested yet.Base on input voltage x current and output voltage x current.






conradelektro

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@gyulasun: Very interesting, thank you for drawing our attention to the LTC3108 and its family of DC-DC converters.

This shows what can be done professionally with a low Voltage source like a Peltier Element. The price for a stable output Voltage and the other niceties (PGOOD)  is of course a few mA used up by the many electronic components.

The high price of about Euro 10.--  probably means that the market demand is low.

In the data sheet one reads: "The LTC3108 can also be used to trickle charge a standard capacitor, supercapacitor or rechargeable battery, using
energy harvested from a Peltier or photovoltaic cell."

But exactly for this application magpwr's very simple circuit might be better, because one does not need all the high end features (PGOOD, noise reduction with various capacitors, three different stable output Voltages).

Once more I am thinking about building a very simple device with two Peltier elements that charges a small 1.2 V rechargeable battery whenever I light the ceramic stove in my living room. See the attached drawing, the "device" is intended to lean against the ceramic stove.

Greetings, Conrad