Hydrogen Product By Photovoltaic Electolytic Cell

[Turtle]

I have used this setup as a demonstration of electrolysis of water into Hydrogen & Oxygen before, however I used a power supply and did not actually 'use' the gases other than show how they burn. :hihi: This time, I'm using a photovoltaic solar panel for the juice and I intend on trying to use the gas for at least a little gas light.

 

In operation, fill the collection bottles with electrolyte (salt water) and cap them, then submerge them in the tub of electrolyte, secure them in place, and remove the caps. Place an electrode in the neck of each bottle and connect to the panel. As the gas is produced it displaces the electrolyte in the bottles.

 

I do have questions here.:confused: If the tub is shallow as the lower part of the drawing below, is the gas in the collection bottles at 1 atmosphere of pressure when they are completely filled? If I put the bottles completely submerged in a deep cell as in the dotted/grayed upper part of the drawing, will the pressure in the collection bottles be higher when filled than the first arrangement?

 

I have to make some supports for the bottles (they float away when they fill if you don't secure them! :eek:) and I should be in production by tomorrow. Adieu!

[Turtle]

Decided to go with the KISS principle for holding the bottles; I'll put something on top of them when I have too. :confused: Here's the cell with the bottles full of electrolyte, the bright shiny copper electrodes, and the tub that makes the cell. The question now is not if this is slow, but just how darn slow is it.

 

YouTube - Electrolytic Cell Preparation 1 http://www.youtube.com/watch?v=cLj8PqhlSow

[Zythryn]

My understanding is creating hydrogen with solar cells is exceedingly slow.

I think there is some information about the speed of this process available regarding Honda's fuel cell test cars in California.

I would love to hear what you get for rate of hydrogen production.

[Zythryn]

Found it!

The system, when running exclusively on solar energy, can produce about 5,700 liters (at 350 bar) of gaseous hydrogen per year. This is enough to fuel one car for a year.

This is from http://www.ieahia.org/pdfs/honda.pdf

 

It uses a 8kw solar array for power and can use grid power as well for more production.

[Turtle]

Found it!

 

This is from http://www.ieahia.org/pdfs/honda.pdf

 

It uses a 8kw solar array for power and can use grid power as well for more production.

 

I can't read the caption details on the drawing showing the whole setup. I'm particularly interested in how to pressurize the collected gas. Other than a pump, how do you find my idea to submerge the collection bottle?

 

My collection bottles have many tiny bubbles clinging to their inside walls this morning. It is cloudy, cool, and raining, and I measure 8 volts from the panel (panel is rated 5 Watts).

...

Will post updates, photos, & vids as seem appropriate. :sun:

 

It is the kind of gray, cold, wet NW day that I signed up for. 2" of rain in as many days. Nonetheless, the cell is bubbling away on day 1. Here's a clip, brightened for clarity.

 

YouTube - Electrolytic Cell Operating - Day 1 http://www.youtube.com/watch?v=eyfS_RnVyUk

 

PS Crap! I edited instead of quoted!! Lost that bit to the aether. :doh:

[Turtle]

Breaking News.... I hate how every dingity danged story these days is 'breaking' news. :rant: :doh:

 

Let's call it an update. It is dark here now, 5:33pm PST, and I disconnected the photovoltaic panel propped in the South facing window behind the cell, to check if the outside lights produced any voltage; nada, zip, nothin'. With the multimeter at the DC voltage 2.5 V scale I saw no deflection at all.

 

When you got a meter out ya hook things up to it :hihi:, so I went for the leads from the electrolytic cell and lo & behold :evil: a voltage of ~ 1/40 Volt. Will this voltage hold stable no matter the volume of gases in the collection bottles?

 

Oh, what to do with the Oxygen? I think I'll suck it out with a straw when the bottle's full for a 20 oz pick-me-up. ........:sun:

[Turtle]

Day 2: Noon - Everything is gray and not a patch of clear sky to be had, but the panel is happily providing a steady 15 Volts. As we might expect, there is more accumulated Hydrogen than Oxygen...nearly twice as much it looks like. :cup:

 

With the panel disconnected for the voltage check, I metered the cell again and had a surprising, if not shocking, result :(; the meter surged up to 1/2 volt and then steadily declined over a minute or so to a bare level. Seems we have some capacitance in the cell as well.

 

That's all I got. :) :)

[Zythryn]

Very fun, thanks for the updates Turtle:)

[freeztar]

I metered the cell again and had a surprising, if not shocking, result :); the meter surged up to 1/2 volt and then steadily declined over a minute or so to a bare level. Seems we have some capacitance in the cell as well.

 

That's interesting. I guess that's quite beneficial for serving up a fairly constant voltage despite passing clouds.

[Turtle]

Very fun, thanks for the updates Turtle:)

 

Danke. You know me...nuttin' butt fun.

:D

/forums/images/smilies/banana_sign.gif

 

I metered the cell again and had a surprising, if not shocking, result :hyper:; the meter surged up to 1/2 volt and then steadily declined over a minute or so to a bare level. Seems we have some capacitance in the cell as well.

That's interesting. I guess that's quite beneficial for serving up a fairly constant voltage despite passing clouds.

 

To clarify, the photovoltaic panel has blocking diodes which stop any current flow back into it. The capaciter-like discharge I mention is from the electrolytic cell while it was disconnected from the solar panel.

 

Also because of the blocking diodes, you cannot put the photovoltaic panels in series and produce a higher voltage, only in parallel to increase the amperage. Here is a nice discussion on the topic of the roles of voltage and amperage in electrolysis:

 

Electrolyzer - encyclopedia article about Electrolyzer.

... A higher current flow (amperage) through the cell means it will be passing more electrons through it at any given time. This means a faster rate of reduction at the cathode and a faster rate of oxidation at the anode. This corresponds to a greater number of moles of product. The amount of current that passes depends on the conductance of the electrodes and electrolyte, though it also depends on how much current the power source itself can generate. Current also makes a difference in that it can shift chemical equilibria by sheer mass action. The processes in an electrolytic cell with just two or three reactants can become very, very complex. Most of the time it is best to search the literature to see what current density works best for a desired process. For instance, metals plated at a certain current density might form a durable and shiny coating on the substrate, while some other current density might form an excessively grainy, dull coating.

 

A higher potential difference (voltage) applied to the cell means the cathode will have more energy to bring about reduction, and the anode will have more energy to bring about oxidation. Higher potential difference enables the electrolytic cell to oxidize and reduce energetically more "difficult" compounds. This can drastically change what products will form in a given experiment. On a practical level, both current and voltage determine what will form in a cell. ...

[Turtle]

Addendum: Going by eye, I have about 2 teaspoons of Hydrogen in my 20 oz. bottle. That's ~1 teaspoon/day, and @6 teaspoons/ounce, that's 120 days to a fill-up! :D

 

On another bad note, either through siphon action alone, or a combination of capillary and siphon action, the electrolyte passed through the wire insulation like the pipe that it is, and was dripping out the end near the connection to the panel. :hyper: I have elevated the conductors in the hope of stauchning the flow. Good grief & oh bother....

[Turtle]

Day 3 Noon: Several developments to report. First, it has broken out in sunshine here for awhile, and the negative terminal is bubbling out Hydrogen like crazy. :bounce:There is now around an ounce of collected gas in the bottle.

 

Next, and somewhat puzzling, is the positive terminal is not bubbling that I can tell and the amount of collected Oxygen looks pretty much the same to me as yesterday. I may be losing the gas out through the electrolyte soaked lead wire I mentioned last post. :(

 

Moving on to the electrolyte, it has turned a very nice shade of pastel teal. Copper compounds anyone? What , if any, of these can I recover?

 

Finally, a fella on YouTube who is an electrolysis enthusiast subscribed to my videos overnight. :D Here's his channel: YouTube - Broadcast Yourself.

Dude is puttin' some serious juice into his electrolytic cell; in one clip he has 150+ volts and nearly 3 Amps goin' in! :)

 

That's a wrap. ;) :phones:

[Turtle]

Update: 3:00 pm

 

 

In spite of strong Sun, the cell stopped working. :( Looking around a bit, I found that the positive electrode was completely gone, electrolyzed away. I'm using #12 or #14 braided copper wire, so I see already that's not the best choice. Anyway, I just stripped back more wire on the lead and set it going again. On the negative side, the electrode on the other hand is growing. :phones:

 

That's a wrap. :cup: :eek2:

[Turtle]

Update Dusk: Activity is falling off as night sets. Even after stripping new wire, I saw no bubblage in the positive electrode Oxygen producing side. The bubblage that is in that bottle may be at least 1/2 accounted for by air trapped when I originally filled it. :( Hmmm... Could be either it's leaking out the conductor, or I have too little voltage and/or amperage. I can add another 5 Watt panel of the same manufacture and if I get Oxygen bubblage then I know it was Amperage as all else was equal. :phones:

 

After disturbing the electrodes, the negative electrode shed a bunch of fine brownish-yellow-orange particles so that the entire electrolyte in the bottle is now distinctly ooky, and the electrolyte in the main cell is becoming ookier by the time-step. :cup:

 

That's a wrap. :eek2:

[freeztar]

Addendum: Going by eye, I have about 2 teaspoons of Hydrogen in my 20 oz. bottle. That's ~1 teaspoon/day, and @6 teaspoons/ounce, that's 120 days to a fill-up! :doh::)

 

:eek2:

How are you "going by eye" when both hydrogen and oxygen are colorless?

On another bad note, either through siphon action alone, or a combination of capillary and siphon action, the electrolyte passed through the wire insulation like the pipe that it is, and was dripping out the end near the connection to the panel. :( I have elevated the conductors in the hope of stauchning the flow. Good grief & oh bother....:cup:

 

Hmmm...What does elevating the conductors do to stop either capillary action or siphoning? Perhaps I'm misunderstanding what you mean by elevating the conductors. Can you elaborate please? ;)

 

For the wire insulation problem, perhaps you could poke holes in it at even intervals to prevent electrolyte passage (the holes should lessen any siphoning potential as well). But of course, it would be best to prevent any movement in the first place. And to that end, I'll have to put on the old thinking cap and see what it brings me. :phones:

[Turtle]

:eek2:

How are you "going by eye" when both hydrogen and oxygen are colorless?

By the size of the bubble in the bottle. Since the bottle started full of liquid electrolyte, any bubbles in there have to be Hydrogen coming off the electrode. No one answered my earlier inquiry about the pressure of this bubble, which I posited is 1 atmosphere. Do you concurr? Slightly higher than 1 atmosphere perhaps because the opening is submerged and we have to account for the hydraulic head in the main cell?

 

 

Hmmm...What does elevating the conductors do to stop either capillary action or siphoning? Perhaps I'm misunderstanding what you mean by elevating the conductors. Can you elaborate please? :)

In the video of post #5, you see the conductors leaving the main cell and bend over downward on the outside. They continued down to the shelf the cell is sitting on & there made the connection to the panel. This arrangement of a tube is the classic siphon. I raised the connection point so the leads now leave the main cell directly up; I may still have capillary action in there, but the leaking has stopped.

 

For the wire insulation problem, perhaps you could poke holes in it at even intervals to prevent electrolyte passage (the holes should lessen any siphoning potential as well). But of course, it would be best to prevent any movement in the first place. And to that end, I'll have to put on the old thinking cap and see what it brings me. :phones:

 

I'm going to make a new electrode for the plus side out of some solid copper wire, and seal the gap with the insulation where I strip wire bare; will try using hot-melt glue.

 

Looking over some of the references I gave, I see they have platinum as the preferred metal for both electrodes when the aim is electolysizing water for Hydrogen. I've seen gold suggested as well, and both these noble metals are highly resistant to break down by electrolysis. Takes care of the growing crud problem I have now by using copper, but I'm not likely to procure any platinum any time soon. :cup: :(

 

That's a rap...erm...wrap. :doh:

[freeztar]

By the size of the bubble in the bottle. Since the bottle started full of liquid electrolyte, any bubbles in there have to be Hydrogen coming off the electrode.

 

Ok, I'm an idiot. :phones: I had not watched that video until now as I can't watch utube at work and that's where I've been following this thread mainly.

 

No one answered my earlier inquiry about the pressure of this bubble, which I posited is 1 atmosphere. Do you concurr? Slightly higher than 1 atmosphere perhaps because the opening is submerged and we have to account for the hydraulic head in the main cell?

 

That seems like a valid assumption. Q would probably be helpful for calculating this. I'm not savvy with pressure equations. :(

 

In the video of post #5, you see the conductors leaving the main cell and bend over downward on the outside. They continued down to the shelf the cell is sitting on & there made the connection to the panel. This arrangement of a tube is the classic siphon. I raised the connection point so the leads now leave the main cell directly up; I may still have capillary action in there, but the leaking has stopped.

 

Gotcha, thanks! ;)

I'm going to make a new electrode for the plus side out of some solid copper wire, and seal the gap with the insulation where I strip wire bare; will try using hot-melt glue.

 

Looking over some of the references I gave, I see they have platinum as the preferred metal for both electrodes when the aim is electolysizing water for Hydrogen. I've seen gold suggested as well, and both these noble metals are highly resistant to break down by electrolysis. Takes care of the growing crud problem I have now by using copper, but I'm not likely to procure any platinum any time soon. :cup: :doh:

 

That's a rap...erm...wrap. :)

 

Maybe you could use an iridium-rich meteorite as the *odes. :eek2:

On second thought, Cu seems perfect. :D