Author Topic: 102 plates drycell  (Read 23094 times)

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Re: 102 plates drycell
« Reply #72 on: August 10, 2010, 18:18:59 pm »
Also how much electrolyte is in your cell? I have ~3% and i get 2A at 1.7V per single cell. It doesn't get warm under 1.85V / cell which is good, but i have to optimize far more to get my desired 150W/l/min

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Re: 102 plates drycell
« Reply #73 on: August 10, 2010, 18:41:30 pm »
Hi Haithar


Voltage * Amperage = Power


Faraday stated that using platinum electrodes you need 1,23v to allow electrolytic conduction in the water, this mean that under this max voltage water independently of witch electrolyte or the amount of it dissolved, will behave as a dielectric. Because there is not enough energy to open the holes of conduction. Just like a transistor.


From the theory than we knew that this amount of energy transformed into h2 in this "100"% efficient electrolysis would be the same that you need to put in it to realize this work.


Now i want you all to think!


How can we create a water transistor ( a way to lower the energy required to conduct the current? )


Do you see that voltage is directly and proportionally bounded to the idea of efficiency?
 




 
 

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Re: 102 plates drycell
« Reply #74 on: August 10, 2010, 19:25:47 pm »

Faraday stated that using platinum electrodes you need 1,23v to allow electrolytic conduction in the water, this mean that under this max voltage water independently of witch electrolyte or the amount of it dissolved, will behave as a dielectric. Because there is not enough energy to open the holes of conduction. Just like a transistor.
You are forgetting the overpotentials needed in addition to the 1.23V. It's right that 1.23V is the theoretical minimal voltage needed to electrolyse water and the overpotential of platinum on the hydrogen side is only -0.07V so electrolysis is possible at low voltage. However efficiency in terms of electrical input vs. energy content of created gas can only be measured when knowing the exact overpotential at the current temperature, material, current density,.. 1.23V cannot used as the 100% efficiency value in a real setup.

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Re: 102 plates drycell
« Reply #75 on: August 10, 2010, 23:30:38 pm »
Hello,


i previously wrote a lot and have lost everything =(... here i go again


I did an experiment witch i posted on my thread about resonant electrolysis... in witch i had a resonant tank at 27khz 20amps and 700 volts i was inputing about 80watts and i had between the electrodes that were made from ( 2 tubes steel and 2 internal bolts stainless steel ) 1,44 volts. Note i had 20 amps flowing at 1,44 volts or 28watts were going on electrolysis and it were going at 85% efficiency  = 1/(1,44/1,23)  (excluding the losses on the tank and input circuit witch at the time was not the ideal)  so about 9ml of water was being converted into h2 in one hour

I had many losses on the capacitors of the tank, the inductor, the rectifier stage, the mosfet because they were not designed for this. Some capacitors blowed from the heat, i used 20 x 1n4007 diodes in parallel... 


I was getting that much amperage because the current was passing thru the water only because of the inertia and not because of the over potential,  current was 180° from voltage so there was virtually no voltage across the electrodes the only voltage was due to the potential required to open the holes of conduction. 


« Last Edit: August 11, 2010, 00:03:13 am by sebosfato »

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Re: 102 plates drycell
« Reply #76 on: August 10, 2010, 23:51:40 pm »
http://en.wikipedia.org/wiki/Overpotential


Check this
Activation overpotential
The potential difference above the equilibrium value required to produce a current which depends on the [/color]activation energy of the redox event. While ambiguous "activation overpotential" often refers exclusively to the activation energy necessary to transfer an electron from an electrode to an analyte. This sort of overpotential can also be called "electron transfer overpotential" and is a component of "polarization overpotential", a phenomenon observed in cyclic voltammetryand partially described by the Cottrell equation.
Reaction overpotentialReaction overpotential is an activation overpotential that specifically relates to [/color]chemical reactions that must formally precede electron transfer. The reaction overpotential can be reduced or eliminated with the use of homogeneous or heterogeneous electrocatalysts. The electrochemical reaction rate and related current density is dictated by the kinetics of the electrocatalyst and substrate concentration.
The
platinum electrode common to much of electrochemistry is also electrocatalytically non-innocent for many reactions. For example, hydrogen is oxidized and protons are reduced readily at the platinum surface of a standard hydrogen electrode in aqueous solution. If electrocatalytically inert glassy carbon electrode is substituted for the platinum electrode, then the result is irreversible reduction and oxidation peaks with large overpotentials.
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Re: 102 plates drycell
« Reply #77 on: August 10, 2010, 23:57:28 pm »
Thus of course 1,23v can be used as 100% efficiency voltage, however you need Platinum electrodes and there will be some losses on the input circuit depends on the design. It can be made to have almost 99% efficiency if you want but is costy...

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Re: 102 plates drycell
« Reply #78 on: August 10, 2010, 23:59:15 pm »
Hello,


i previously wrote a lot and have lost everything =(... here i go again


I did an experiment witch i posted on my thread about resonant electrolysis... in witch i had a resonant tank at 27khz 20amps and 700 volts i was inputing about 80watts and i had between the electrodes that were made from ( 2 tubes steel and 2 internal bolts stainless steel ) 1,44 volts. Note i had 20 amps flowing at 1,44 volts or 28watts were going on electrolysis and it were going at 85% efficiency  = 1/(1,44/1,23)  (excluding the losses on the tank and input circuit witch at the time was not the ideal)


I was getting that much amperage because the current was passing thru the water because of the inertia and not because of the over potential,  current were almost 180° so there was virtually no voltage across the electrodes the only voltage was due to the potential required to open the holes of conduction.
that's nice and i'd like to hear more of it, but it's quite off-topic. in dry cells like steve and mine we are dealing with ordinary direct current at the lowest possible voltage to amps ratio.


probably steve can move this to a new thread.








I agree with you that when using platinum electrodes 1.23V is the minimum voltage. however we are using stainless steel  ???

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Re: 102 plates drycell
« Reply #79 on: August 11, 2010, 00:08:30 am »
If you use steel the voltage maybe is smaller, however i'm not sure it both electrode must be steel... using NaOH the steel didn't corroded too much...  however there was always some iron powder on the bottom of the tubes...


=) Hope i helped somehow


I still believe that we should understand how to construct a mosfet made of water. 


Best regards