how to keep water from freezing

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fr00t
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Re: how to keep water from freezing

Postby fr00t » Mon Oct 11, 2010 9:33 pm UTC

Has the OP realized that what he wants is probably really oxymoronic and wasteful?

Anyways, there are much easier and cheaper ways to improve MPG. The problem isn't gasoline engines, but aerodynamic efficiency. I recommend you hit up a forum like ecomodder.com or gassavers.org. There were people getting regular cars up into the 70-90 MPG at highway speeds, and I recall some trucks getting up to 40-50. Keep in mind most/all of this was due to aerodyanmic improvements that were done in someones garage using no more than corrugated plastic and such. For an extreme example, adding a full boat-tail to your car will net something like 10-20mpg.

Carnildo
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Re: how to keep water from freezing

Postby Carnildo » Tue Oct 12, 2010 5:13 am UTC

frezik wrote:
Carnildo wrote:
savanik wrote:Antifreezes are typically composed of polar compounds, which will not affect the conductivity of the water. Depending on what you've mixed into the water to make it conductive, these chemicals may react and toxic gases may be emitted which would make your vehicle difficult to operate.

This is worth repeating. Salt, for example, is an obvious choice, but it tends to be counterproductive. Yes, you'll get hydrogen at one electrode, but at the other, the chlorine will react in place of the oxygen, giving you a stream of chlorine gas to deal with.


I've heard about this problem before in using NaCl in electrolysis setups, but I'm not sure it's true. If you're getting elemental chlorine off that reaction, then you should also be getting elemental sodium, which should be even more exciting than chlorine when it meets such a wet environment. If the NaCl is actually part of the reaction, then it must be in very trace quantities or else the whole apparatus would blow up.

As I recall, the reactions involved are:

NaCl -> Na+ + Cl- (Salt dissolves in water)
2H2O -> OH- + H3O+ (Water self-ionizes)

At the electrodes:
2Cl- -> Cl2 + 2e-
2H3O+ + 2e- -> H2 + 2 H2O

leaving you with 2 NaOH in the water -- which is exciting in its own right.

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Coffee
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Re: how to keep water from freezing

Postby Coffee » Tue Oct 12, 2010 11:45 am UTC

No need to lye about it...
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Tass
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Re: how to keep water from freezing

Postby Tass » Tue Oct 12, 2010 1:26 pm UTC

Coffee wrote:No need to lye about it...


Win

Ender2024
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Re: how to keep water from freezing

Postby Ender2024 » Thu Oct 28, 2010 6:47 am UTC

jaap wrote:
Challenger Red wrote:when a car starts, it pulls energy off of the battery to fire the engine. once the engine is going, the battery recharges to its maximum level, but the engine/alternator continues to produce enough energy to charge the battery and run the engine (at least, this is what appears to happen, i know very little about how engines really work).


There seems to be a misconception in there. While an engine clearly produces enough energy from its fuel to do its job and on top of that to top up the battery, that doesn't mean that once the battery is fully charged the engine is continually producing surplus energy that is going to waste.
When the battery is charging, the alternator is more difficult to turn and this places a load on the engine. When the battery is full, the alternator is easy to turn, and the engine is under a lighter load, and so uses up less fuel. You can actually hear this in some cars that the engine, running stationary, changes in pitch when you switch the air-conditioner on or off.
So when the battery is full the engine is not producing surplus energy that it isn't using, it is simply producing less energy. What is does have is more spare capacity for you to use when you press the gas pedal.
If you hook up an H2 generator, you are once again putting an extra load on the engine. Sure, it can handle it, but this does put an extra load on it that it didn't have before, and so cost energy/fuel to run (and most likely much more than the H2 later produces).


First, the air conditioner's compressor unit is powered directly though the engine via a belt. It has it's own electronic clutch to engage and disengage it from the engine, so when it is off it doesn't effect fuel mileage. The change in engine pitch when turning the AC on is due to the compressor's direct connection to the engine, not increased load on the alternator. Google "how does a car air conditioner work", click the first link, go to the second page and read about the compressor.

Second, the battery only really exists to start the vehicle and power lights and electrical devices when the engine is not running. While the engine IS running, a the alternator also runs, providing power to recharge the battery and power all electrical devices. Any excess energy is just dumped to ground, completely wasted. While the H2 plant does use more energy than it produces, it is a means of recapturing a small portion of that lost energy and give it another chance to make the car go. Google "how does an alternator work" and click the first link.

Better to just use the power directly rather than making electricity, but yes, you can make more efficient engines using stirling engines, it is, however, not worth the extra weight and investment, if it was car factories would be making them.


Another option that would help you power your H2 generator in addition to or instead of the alternator is thermoelectric materials (google it). These materials convert heat energy directly to electricity (much better than the stirling idea, as there are fewer energy conversion steps in which to lose more energy and far more energy for the weight). They usually require a large thermal gradient (say, from room temp on one side to 200 C or more on the other), but installing a few right next to the radiator where heat is being bled off anyway would give you a few volts to work with.

Also...

Carnildo wrote:
frezik wrote:
Carnildo wrote:
savanik wrote:Antifreezes are typically composed of polar compounds, which will not affect the conductivity of the water. Depending on what you've mixed into the water to make it conductive, these chemicals may react and toxic gases may be emitted which would make your vehicle difficult to operate.

This is worth repeating. Salt, for example, is an obvious choice, but it tends to be counterproductive. Yes, you'll get hydrogen at one electrode, but at the other, the chlorine will react in place of the oxygen, giving you a stream of chlorine gas to deal with.


I've heard about this problem before in using NaCl in electrolysis setups, but I'm not sure it's true. If you're getting elemental chlorine off that reaction, then you should also be getting elemental sodium, which should be even more exciting than chlorine when it meets such a wet environment. If the NaCl is actually part of the reaction, then it must be in very trace quantities or else the whole apparatus would blow up.

As I recall, the reactions involved are:

NaCl -> Na+ + Cl- (Salt dissolves in water)
2H2O -> OH- + H3O+ (Water self-ionizes)

At the electrodes:
2Cl- -> Cl2 + 2e-
2H3O+ + 2e- -> H2 + 2 H2O

leaving you with 2 NaOH in the water -- which is exciting in its own right.


Since all of these reactions occur on a microscopic (molecular) level, there is negligible danger of any chemical reactions getting out of hand. If you have a few tablespoons of salt in a gallon or two of water, you might have a few chlorine atoms escaping and leaving sodium behind at any given second during the electrolysis reaction, but they will be distributed throughout the reaction medium (and atom here, an atom there; primarily closer to the electrodes). You will not have immediate corrosive destruction of your engine due to sudden release of chlorine and you won't have an explosion due to the accompanying production of sodium. At the rate of a few atoms at a time, you can expect any chlorine to combine with carbon, hydrogen, or oxygen during combustion in the cylinders and be forced out with the exhaust gas, and the sodium will combine an atom at a time (far slower than the impressive reaction you get from suddenly dropping a block of it into your reaction tank) with the water to produce sodium hydroxide which is also helpful in electrolysis (could cause some corrosion if your tank leaks).

I think people have a tendency to hear "chlorine" and think "corrosion" and to hear "sodium" and think "explosion", but we are talking about minuscule amounts at any given time here (even if you were using seawater), not the big flash you may have seen in chemistry class or on Mythbusters.

To Challenger Red: Sorry I haven't come up with a good solution to the freezing issue yet, I am working on an H2 system of my own, and I need to know how to prevent freezing as well. After I found this thread, I talked to a guy who serviced taxies in the DC area for at least 10 years, and he confirms what I said about the alternator producing excess energy. I know from my chemistry experience in engineering school that the reactions described above are possible, but not likely occur to any degree you would have to worry about (at least not in this universe). Salt will help with freezing, but even at seawater concentrations it will only get you an extra 2 degrees C. You'd need a 50/50 mix of antifreeze in your tank to get any good results that way, but it would dilute the water (slowing the reaction) and take up half the space in your tank (I don't know if Savanik is correct in that it might react). You could install a small heater that plugs into an external outlet (like what they use in horse troughs), but that makes it more complicated. Maybe a method of capturing engine heat and pushing it through your tank, but then the engine has to warm up first...

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Velifer
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Re: how to keep water from freezing

Postby Velifer » Thu Oct 28, 2010 4:17 pm UTC

Good first post, welcome, but if you come in here being pedantic, you better know your shit:

Ender2024 wrote:First, the air conditioner's compressor unit is powered directly though the engine via a belt. It has it's own electronic clutch to engage and disengage it from the engine, so when it is off it doesn't effect fuel mileage. The change in engine pitch when turning the AC on is due to the compressor's direct connection to the engine, not increased load on the alternator.

That accounts for much of the whine, yes. The alternator does have an increased load: it responds to the load from the A/C fan circulating air into the passenger compartment, and on some models, the electric fan behind the radiator. Also, that clutch, when not engaged, is not frictionless, so there's going to be a (near-negligible) efficiency loss on a car that's equipped with A/C, even not in use.

Ender2024 wrote:Second, the battery only really exists to start the vehicle and power lights and electrical devices when the engine is not running.

A modern car without a battery is a lawn ornament.

...installing a few right next to the radiator where heat is being bled off anyway

Why not on the exhaust manifold where the temperature gradient would be much higher?

Since all of these reactions occur on a microscopic (molecular) level,

Are there any chemical reactions that don't happen at the atomic/molecular level?

You will not have immediate corrosive destruction of your engine due to sudden release of chlorine and you won't have an explosion due to the accompanying production of sodium. At the rate of a few atoms at a time, you can expect any chlorine to combine with carbon, hydrogen, or oxygen during combustion in the cylinders and be forced out with the exhaust gas, and the sodium will combine an atom at a time (far slower than the impressive reaction you get from suddenly dropping a block of it into your reaction tank) with the water to produce sodium hydroxide which is also helpful in electrolysis (could cause some corrosion if your tank leaks).

Much of the sodium and chlorine would be apt to stay in solution. The problem is that most things that work well also tend to corrode most electrodes. That either means frequent replacement or expensive alloys. One more big hit to that mythical cost savings.

You could install a small heater that plugs into an external outlet (like what they use in horse troughs), but that makes it more complicated.

...and eats even the most optimistic estimates of savings.
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Wummi
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Re: how to keep water from freezing

Postby Wummi » Thu Oct 28, 2010 6:24 pm UTC

spontanius idea: heat from exhaust pipe + steam engine = hello steampunk-hybrid

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Sockmonkey
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Re: how to keep water from freezing

Postby Sockmonkey » Thu Oct 28, 2010 6:43 pm UTC

Yeah, I saw that one in Popular Mechanics I think.

Wummi
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Re: how to keep water from freezing

Postby Wummi » Thu Oct 28, 2010 7:05 pm UTC

seems like bmw had my idea 6 years ago:
http://www.gizmag.com/go/4936/
guess it didn't work out that well..

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Re: how to keep water from freezing

Postby Velifer » Fri Oct 29, 2010 12:26 pm UTC

If you're going steampunk, then skip the internal combustion entirely.
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Re: how to keep water from freezing

Postby Hawknc » Fri Oct 29, 2010 1:25 pm UTC

Velifer wrote:Ender2024 wrote:
Second, the battery only really exists to start the vehicle and power lights and electrical devices when the engine is not running.

A modern car without a battery is a lawn ornament.

In that it's required to complete the circuit, yes. Once the car is started, though, you could (theoretically) bypass the battery and have everything from headlamps to the ECU running off the alternator. It's not something I'd ever advise though. The battery is a good way to smooth out fluctuations in voltage that could affect some of the more sensitive electronics.
Velifer wrote:...installing a few right next to the radiator where heat is being bled off anyway

Why not on the exhaust manifold where the temperature gradient would be much higher?

Anywhere pre-muffler, really. The catalytic converter on modern diesel cars can reach several hundred degrees on the surface. Compare that to radiators, which won't get more than about a 60-70C delta in worst case between radiator surface and ambient (if your coolant is over about 110C, you have other problems anyway).

On the original post, if you wanted to unfreeze water there are historical precedents for heating fluids in vehicles. A number of companies experimented with fuel heaters, particularly in Europe, but they didn't do any favours for fuel mileage and were mostly there to help cars actually start on sub-zero mornings. The simplest way would be to start the engine without H2 and divert coolant from the engine outlet to a heat exchanger where it can heat up the water, then use a thermostat to start generating H2 once the water reaches a certain temperature. As others have noted, attempting to inject hydrogen is not going to save you any money or fuel in the short or long term, but it's an interesting engineering experiment.

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Velifer
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Re: how to keep water from freezing

Postby Velifer » Fri Oct 29, 2010 2:05 pm UTC

Hawknc wrote:In that it's required to complete the circuit, yes. Once the car is started, though, you could (theoretically) bypass the battery and have everything from headlamps to the ECU running off the alternator.


Ah yes, but what a difference between theory and practice...

On old cars with generators, this is true once the engine RPM is high enough. My '51 Chevy was less complicated than my lawnmower. As long as it had air, explosive vapor, and a little spark, it would move. How things have changed. In a "new car" (60's or later) with an alternator, you must have a current to charge the field windings before they work, the modern automotive alternator doesn't contain permanent magnets. That excitation charge comes from the battery. Even up and running with that initial charge, the power from the alternator isn't going to keep the car going. While the rectified square wave from an alternator (after being pumped through the sometimes separate rectifier) is pretty close to DC, it's not enough to keep the ECU/PCM from flipping out, and that's on a fairly old/simple car that only has one computer. No, very few modern cars will run without a battery. (Though in theory, they should... damn electronics everywhere taking the place of good mechanical engineering.)

Alternators are also sized fairly closely to the car, such that pulling off "excess" load will wear them out. A bad battery that needs more than maintenance can take out the alternator. So, don't pull off too much current in an electrolysis rig without dropping in an upgraded alternator.
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Ender2024
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Re: how to keep water from freezing

Postby Ender2024 » Fri Oct 29, 2010 4:28 pm UTC

The guy I talked to recommended only using about as much power as you would for a light bulb, though that's not much and more energy gets you more gas to work with (to a point). That's why the thermoelectrics came to mind; you can get some voltage with no drain on the car's electrical system.

As far as knowing my shit, velifier is correct that I don't know everything (and I stand corrected and humbled on a number of points :oops: ), but we seem to have gotten off the subject. Challenger Red asked how to keep the water in his H2 generator from freezing, and we've turned it into a debate over whether H2 generators are feasible. I'm making my own generator to test that very thing for myself, and if it doesn't work I'll rip it out and forget the whole matter but with winter on the way I won't get to do much of a test if the water freezes until spring (don't mind waiting a few months, but I'm trying to look into all the problems that might arise and the water freezing is a big one). That said, I'll continue my own research and continue to monitor this forum in case anything promising comes up.

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Re: how to keep water from freezing

Postby Jplus » Fri Oct 29, 2010 6:51 pm UTC

Viable solutions to keep the water from freezing have passed, right? You can use ethanol or glycerol or something similar as an antifreeze agent, and you can use the engine coolant to warm up the water for hydrolysis. And only a few posts ago somebody cleverly mentioned that you can use a thermostat to only start hydrolysing when the water has molten.
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Re: how to keep water from freezing

Postby Seraph » Fri Oct 29, 2010 7:39 pm UTC

Velifer wrote:
Hawknc wrote:In that it's required to complete the circuit, yes. Once the car is started, though, you could (theoretically) bypass the battery and have everything from headlamps to the ECU running off the alternator.


Ah yes, but what a difference between theory and practice...

On old cars with generators, this is true once the engine RPM is high enough. My '51 Chevy was less complicated than my lawnmower. As long as it had air, explosive vapor, and a little spark, it would move. How things have changed. In a "new car" (60's or later) with an alternator, you must have a current to charge the field windings before they work, the modern automotive alternator doesn't contain permanent magnets. That excitation charge comes from the battery. Even up and running with that initial charge, the power from the alternator isn't going to keep the car going. While the rectified square wave from an alternator (after being pumped through the sometimes separate rectifier) is pretty close to DC, it's not enough to keep the ECU/PCM from flipping out, and that's on a fairly old/simple car that only has one computer. No, very few modern cars will run without a battery. (Though in theory, they should... damn electronics everywhere taking the place of good mechanical engineering.)

Even computer free cars have a hard time running of an alternator with no battery. I had an early 80's pickup truck with only the most basic electronic parts where the battery failed as a short, so I had to disconnect it. I jumped it off another truck, and it ran fine once it was going but when I turned my headlights on during my trip home the engine stopped stone dead. The draw from the headlights was enough to prevent the alternator from running correctly, and since the alternator needs voltage to run once the voltage dropped there was a positive feedback that killed things pretty quickly. I would imagine that doing the opposite (turning headlights off with no battery) would be even worse, given the fact that the battery tends to be important to eating the resulting voltage spike.


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