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Old 08-28-2008, 02:29 AM   #11
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With baking soda, sodium bicarbonate, the brown sludge formed at first while you "condition" the cell is actually iron carbonate. The carbon is removed from solution and replaced with hydroxide ions from the water, thus your solution turns into sodium hydroxide.
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Old 08-28-2008, 09:55 AM   #12
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thus your solution turns into sodium hydroxide.

So would it be better or best to just start with a sodium hydroxide solution. I get a different type of brown sludge or dust with potassium hydroxide, and it seems to take longer to form.

Another thing I have noticed is that the current through room temperature electrolyte is lower than when it heats up. The lower the current the longer it takes for the water to heat up but it always does. I did run a jar at 1/2 ampere and it never seemed to get hot. I suppose there is a point at which there is adequate amounts of electrolyte so that it acts as a coolant as well. Or perhaps the electrodes need to be larger, I am not certain why everything heats up yet, my first instinct told be it was because of the slight resistance of the water that caused so much current to flow, and that resistance produces heat. Just like the slight resistance in wire is what causes it to heat up with too much current. I am wondering if there is a combination of ratio of electrode surface area, current and electrolyte amount that will produce little to no heat. This all goes a long with my future tests on how much HHO do you really need to improve gas mileage? And is more always better, or is there a point of diminishing returns?

The information on the web about all this is all very obscure and most just seem to want to make money off of their knowing by selling products. Like this thread has mentioned many are very skeptical. I hope my postings here helps some find some level of truth as to whether HHO electrolyzers are really worth it, some seem to question whether they do anything at all. By controlled experimentation I intend to find out. Right now I am just trying to figure out what is happening and why. Sounds like sludge could be avoided by just starting out with sodium hydroxide, but it may be far more economical to start with sodium bicarbonate (baking soda). It would be real convient to find the chemical reaction processes of different electrolyte solutions during electrolosis.

Terry
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Old 08-28-2008, 11:31 AM   #13
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There's a theretical minimum voltage per cell of around 1.2V anything above that is going into heating the water. Watts = Volts x Amps, which is the energy above that which is needed for electrolysis that goes into heating the water. So reducing the amperage reduces the energy going into the water, but it also reduces the power available for conversion to HHO. So best plan is to get the volts per cell as low as possible aand then you can crank up the amps per cell as high as possible. Note that some proportion of the energy needed to split the water can come from environmental or electrolyte heat, thus the cell gets more efficient the hotter it is, requiring a little less voltage, and thus more waste energy goes inot the already hot water. This is when you get a thermal runaway situation.

When finally I get round to setting up my own system, I plan to loop coolant heat into the cell, and shave the voltage per cell low enough that it doesn't even start working until it has soaked some heat from the coolant. Thus it will scavenge waste energy from the cooling system and be less likely to run away. It will be kept at 190F by the coolant. This wouldn't work if you had it set to produce at 70F or so, since by the time it got up to 190 it would be well into thermal runaway territory.
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Old 08-28-2008, 11:36 AM   #14
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Thermal runaway? As in, it starts to boil over?

I should work on some experiments in my apartment this coming weekend. I've got a few multimeters and a bunch of free time. Kinda sounds like fun.
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Old 08-28-2008, 02:06 PM   #15
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Yep, starts to boil over...

Say you're losing 200W of heat into heating it, as it warms up it gets more efficient, then you're putting 250W of heat into it and it gets hotter still and you're putting 300W into it... So they can go from "a little warm" to boiling quite quickly if you're not cautious.
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Old 08-28-2008, 02:51 PM   #16
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Yep, starts to boil over...

Say you're losing 200W of heat into heating it, as it warms up it gets more efficient, then you're putting 250W of heat into it and it gets hotter still and you're putting 300W into it... So they can go from "a little warm" to boiling quite quickly if you're not cautious.
Wow! this fits right into my observations lately, the hotter it gets the more current it draws, and the hotter it gets still. I think what I want to do is put a power conversion control on the unit so I can control the voltage and thus the current fed to it, along with a thermometer. This way I can give it more current at start up until it start rising in temp once it reaches 190 degrees I can back off the voltage to where it is not getting any hotter. This is more waist compared to your running the engines coolant supply through it, but this way I have control and can monitor the temp, voltage and current. I like knowing what is going on.

Terry

P.S. No one has answered my questions about whether it would be better to mix a sodium carbonate solution rather than sodium bicarbonate. Wouldn't this reduce the sludge problem presented by baking soda? Sure which I understood the electrolysis process better with regard to what is going on chemically with different electrolytes.

P.S.S. From what you said would it be better to mix a stronger electrolyte solution to where you were using less voltage than more. I think I could mix a solution of water and potassium hydroxide strong enough to where it would only need 1.2vdc to produce a fair amount of HHO. Would that then not make as much heat, or no heat based on what you said?
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Old 08-28-2008, 03:08 PM   #17
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I should work on some experiments in my apartment this coming weekend. I've got a few multimeters and a bunch of free time. Kinda sounds like fun.
If you email me at tadgesualdo@gmail.com I can send you one of my wire wound electrode set ups for a one quart mason jar like water4gas uses. I have moved on to more surface area than one of those can provide, besides the wall plug blanks are only $1.19 each at Lowe's, cheaper than the source for stainless wire I found locally.

It is fun experimenting with it, but make sure you have some ventilation I don't know what would happen if too much HHO would build up, it might explode. I open a window and put the hose from the electrolyzers into a glass of water so that their isn't a chance of the electrolyzer will blow up. Also take notes this way you can study the results of your tests to help come to conclusions. I don't know how you would be able to tell if it were boiling, there are so many bubbles in their already.

RW,
How did you come up with the 190 degree figure? With all these factors there has got to be points of diminishing returns on how hot the water is, how large the plates are, how strong the electrolyzer mix is, how much current and everything. This is what my bench experiments are trying to determine, ther is everything from soup to nuts on the internet with regard to these.

Terry
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Old 08-28-2008, 04:25 PM   #18
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190 is a typical thermostat temp, the temp the engine coolant will be regulated to. Might be 180, or 195 in your car. So for a start it will be bringing the jar/cell up to 190F, you might have the voltage tuned to start producing a little bit lower, say 170F, but you're not putting that much extra heat in, and the coolant will either keep it warm up to 190F or absorb excess heat from it. I think it might be steaming a fair amount at that point though, but I believe larger concentrations of hydroxide will raise the actual boiling point somewhat. IF you have a "feeder tank is your bubbler" arrangement, then you'll probably recondense most of the steam in there and reclaim it.

I'm pondering floating mineral oil on top of a cell for the purpose of reducing misting of hydroxide into the gas flow when the bubbles burst at the surface, this may also prevent steaming to some extent.

Just gonna go look for a link I posted with some handy data in...
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Old 08-28-2008, 04:39 PM   #19
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Ah this was the one I was thinking of...
http://www.dow.com/causticsoda/phys/index.htm
but they don't have the handy dandy table for boiling point as they do for freezing point. At the top of the page you will notice it given as 293F for 50% solution of sodium hydroxide. However, note also that the freezing point is quite high.
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Old 08-29-2008, 12:19 PM   #20
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Today I induced thermal runaway, it was more difficult than I thought it would be, it took one hour at 4 amps at about 20v, I suppose I could have mixed a stronger electrolyte solution to make it happen faster. Anyway it is interesting, you can't tell very easy it is happening the larger bubble are the first clue, and the water level drops. I have these weird deposits above the water line, that don't mix back in with the water.

My engine compartment seems to heat up the HHO unit and thus heat up the water, so designing with higher water temperatures in mind doesn't seem to be a bad idea. I was also thinking of mounting the unit in front of the radiator to add to the cooling of it to prevent thermal runaway. I am filtering my electrolyte solution today to get out the sludge, I am hoping it doesn't reform, since RW said the solution changes as a result of the electrolosis. I don't know what my potassium hydroxide has morphing into since he said sodium bicarbonate changes into sodium hydroxide.

Terry
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