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Instant Water Boiling

Posted: Wed Oct 29, 2008 12:35 am
by mega_swordman
Hello to all spudders, mega here. Just popping in to run a theory by everyone.

For no reason in particular, I wanted to design a way to make water boil faster. Thus, I came up with this idea:

Electricity produces a large amount of heat when it is not insulated, regulated, and etc. Therefore, running a bust of electricity through water should theoretically heat it up. Using this logic, I came to the conclusion that it you had a heat source under a body of water, and sent electricity through the water in a short burst, then the water will be quickly heated. Then, the heat source underneath the water would be able to keep the water at a steady temperature. See diagram 1.

So I have two questions:
1. Does this idea make sense? Is it plausible (not practical)?
2. If electricity is sent through a body of water, will the water still remain electrified or will the water eventually lose its charge?

Posted: Wed Oct 29, 2008 12:55 am
by Lentamentalisk
no. What you are doing is called electrolysis. The electricity does not so much flow through the water, as cause it to separate into hydrogen and oxygen. If you did manage to pump enough current through to get it to arc, then you would flash boil the water, destroying your face.

Posted: Wed Oct 29, 2008 1:01 am
by mega_swordman
Hmm, that makes sense. Indeed, I have seen the flaw in my design.

That being the case, does anybody else have a suggestion for a way to boil water rapidly?

Posted: Wed Oct 29, 2008 1:07 am
by Lentamentalisk
build reflectors around the pot and burner. Look at a backpacking stove for ideas.
Put 2 Bunsen burners under it.
Put 3 Bunsen burners under it.
Put 4 Bunsen burners under it.
etc.

weld radiators to the pot that will be in the flames, so as to get maximum heat transfer. Look at the Jetboil system how it has those radiators on the bottom.

Posted: Wed Oct 29, 2008 1:17 am
by mega_swordman
Cool, thanks for the idea. I have one more to idea to try.

Electric heaters and hot plates create heat through the use of running electricity through coils. If you wrapped a cylinder with a wire much like a coil, would it heat the water inside any faster or effectively?

Posted: Wed Oct 29, 2008 1:19 pm
by Biopyro
It would just add an extra heat source, of which half of the heat would be radiated into the surrounding air. The most efficient convenient way is a pressure cooker, since it stops the energy evaporating out, and it's insulated to prevent it radiating out.

Posted: Wed Oct 29, 2008 2:09 pm
by SpudUke5
Biopyro wrote:It would just add an extra heat source, of which half of the heat would be radiated into the surrounding air. The most efficient convenient way is a pressure cooker, since it stops the energy evaporating out, and it's insulated to prevent it radiating out.
Ahh good point!

This reminds me of my Chem 1 class.

It takes about 100 degrees Celcius to boil water at 101.3 kPa. Now, if you create a vacuum, the intermolecular forces overcome themselves and they rip apart, causing the water to boil because there is no pressure holding the molecules together.

Now a pressure cooker holds the steam in and creates more pressure which forces the bonds to stay together and causes the boiling point to increase. But, this puts more heat into the system, as well as pressure and causes the food to cook quicker because there is more heat to cook the food(and all of this heat is retained)

So i wouldnt recommend using this method because it takes longer to boil and get a gas, if thats what you want.

Posted: Wed Oct 29, 2008 2:20 pm
by john bunsenburner
Use super heated water! easy! I must say you guys disapinted me! If you want ill make plans for a super heated water generator

Posted: Wed Oct 29, 2008 2:21 pm
by MaxuS the 2nd
This wouldn't work as an electrolysis machine anyway..You need and electrolyte (salt) in order to transfer ions.

Posted: Wed Oct 29, 2008 2:24 pm
by john bunsenburner
Thats wrong if you use salt you get chlorine, what peaple use is sulphuric acid!

Posted: Wed Oct 29, 2008 2:34 pm
by Ragnarok
john bunsenburner wrote:Thats wrong if you use salt you get chlorine, what peaple use is sulphuric acid!
Not actually true, Salt and bicarbonate of Soda are both used, usually by the amateur community.

Acidic compounds are a good choice too, but to say salt is wrong is... well, wrong.

That's a little like saying steam engines don't work because the petrol engine has been invented. Cruder methods aren't "wrong" because there's something more more practical - they still work!

Posted: Wed Oct 29, 2008 2:51 pm
by Hotwired
If you want FAST then introducing your water to a large mass of extremely hot metal, causing it to flash boil should do it.

However it looks like you're trying to be practical about it and steam explosions don't usually qualify as practical :(

Posted: Wed Oct 29, 2008 3:20 pm
by Lentamentalisk
or safe... though they are fun, as long as you don't have to deal with the 3rd degree burns and the likes.

Posted: Wed Oct 29, 2008 3:33 pm
by rp181
calcium or potassium, soduim dropped into water heats it.

Posted: Wed Oct 29, 2008 4:32 pm
by psycix
May I point out that the size of the contact area of heating is also important.
It is not only the amount of energy one can put in, but it should be distributed somewhat.

If all energy is applied via a small contact area (like when a chunk of very hot metal is put in it), the water flash-boils somewhat on that point, and alot of steam will violently come off.
Also, a thin film layer of steam will isolate your heating element from the water.

Add the same energy via a larger area, and the problematic effects disappear.