Sciencemadness Discussion Board

How can I speed up chlorine gas production in solar-powered electrolysis cell?

Terminus_Est - 7-3-2016 at 15:27

I've recently made a divided electrolysis cell for the purpose of producing chlorine and I intend to run it using three small solar cells that are each rated at 7.2V and 100mA. After testing to see if it worked with one cell, it did and the chlorine was successfully contained in the anode's half of the cell. It was rather slow though.

But here's the catch. How should I link the three cells so that I get the right amount of power necessary to quicken the gas' production? Should I link them all in series wiring or parallel wiring?

Varmint - 7-3-2016 at 16:35

Parallel

macckone - 7-3-2016 at 18:04

You should use separate electrodes. Voltage imbalances make a single electrode less efficient. Also you may want multiple cells in series as your voltage is higher than desirable.

IrC - 7-3-2016 at 18:13

Quote: Originally posted by Varmint  
Parallel


Not so fast. If the cell has low conductivity it may not be drawing the 100 ma each solar panel can deliver (assuming sunlight is full, bright). If so putting any number in parallel will not alter the rate* since the cell is not drawing any more current. In this case increasing the voltage is the only way. If he had one more he could put two in parallel in series with two more in parallel. This would provide 14.4 volts at 200 ma. Or just use two of the three in series to give 14.4 volts at 100 ma.

* except adding more in parallel would reduce the generators internal resistance which can increase current flow. Again, only if the cell had a low enough impedance to draw more current.

Varmint - 7-3-2016 at 18:44

But, inter-electrode gap should be set to draw maximum current.

If you go series, then you'll only get 1 unit of current, parallel = 3.

You should define problems like this by the voltage required for the actual result required, the electrolysis, and set the electrode area/spacing to use the most current possible.


IrC - 7-3-2016 at 19:27

My point was if the impedance of the cell is such it cannot draw more than 100 ma, then no number of solar cells in parallel will significantly increase current flow unless the source voltage is increased. Simple OHM's law. It is an unknown however as he never mentioned actually measuring the current draw and voltage across the cell so all we can do is guess. Just because he has specs for the solar panels does not actually tell us if they are (or can) provide the specs quoted, we do not even know the intensity of light. Guessing with the information provided is all one can do, except obviously increasing the voltage will increase current draw and therefore cell production rate to a limit of whatever the initial conditions given internal geometry. Which was the actual question. What the OP needs to do is actually provide these measurements and mechanical details, we do not even know how conductive the solution is nor do we know the electrode area and spacing.

"If you go series, then you'll only get 1 unit of current, parallel = 3."

Edit to clarify: it is not how many units the source provides that matters if the load cannot draw more than the output of one, it will only draw what it can draw even if the amperage of the source was infinite. I agree with the electrode comments but the question was about series or parallel. The OP needs to measure the draw and if it is indeed more than 100 ma then parallel would increase it up to the maximum the cell can load the source.


[Edited on 3-8-2016 by IrC]