General Question

ktsnipper's avatar

How can I convert electricity to heat?

Asked by ktsnipper (7points) February 15th, 2009

I want to be able to use electricity to temporarily heat up certain metal items (without turning them into something that can kill me). Is this possible/safe for a non-electrician? How does a portable electric heater convert that electricity to heat?

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14 Answers

TaoSan's avatar

run it through a coil of conductive yet resistant material. Copper would work.

Don’t electrocute yourself!!!!

Jayne's avatar

Connecting a voltage source to any conductive material will cause a current, and this current running through the resistance of that material will be partially converted into heat. Because power, or change in energy over time, is related to voltage squared over resistance, the lower the resistance of the metal for a given voltage, the more heat will be generated. I think. This means that if you want more heat from a given type of metal, use as thick a gauge as possible. As for safety, a small area of the metal will be essentially an equipotential surface, so touching it is only a problem if you are grounded. Which is, for a simple set-up, always, so don’t do it.

ktsnipper's avatar

So, if I were to plug in a car battery to a segment of chain link fence and lay that down on my 100 ft. driveway, it would be a safe and effective way of melting a couple feet of snow and ice? Of course, safety is important… I’m not interested in dying or even getting shocked just to save myself some shoveling. A lot of shoveling, actually, and lots of time, but anyway…

Here is an unaffordable version of what I want:

And, I’m guessing jumper cables would work? Ultimately, a way to plug this into a wall outlet would be great.

Thanks for the responses so far. I love this site… need to visit more often.

Harp's avatar

Yeah, I’m pretty sure that if you tried that with house current, you’d never have to shovel snow again or take out the trash, or wash dishes, or shave…

We love you, too. We’ll even come shovel your driveway for you if you swear not to do this.

ktsnipper's avatar

He he he… ok, I swear.

steelmarket's avatar

@kt, if you are going to do any experimenting, please start out small-scale and power it with DC (direct current) and not AC (alternating or household current)!!! Use a variable DC power source, like the power supply of a N-gauge model railroad setup.
It is a little harder to kill yourself with DC.

Breefield's avatar

Or you could save yourself the whole “might kill yourself in the process” of this specific DIY and just buy some heating strips like that….

ktsnipper's avatar

Yeah, I don’t think I’ll be attempting anything like this. Electricity scares the h*** out of me, but I did want to know what was involved.

Maybe somebody much smarter than me will come up with a DIY that we can all do without danger and save a couple grand.

gailcalled's avatar

@Harp; The apple does not, indeed, fall far from the tree. Lucky tree; lucky apple.

La_chica_gomela's avatar

How about you just buy a space heater? It will convert electricity into heat very efficiently. You can even put “metal objects” near it, and they will get warmer.

RocketGuy's avatar

Better to buy something well tested. Sounds like you want to use electricity to melt ice. Water is a good way to cause electrical problems.

28lorelei's avatar

You need something that is high resistance so the current is forced through it. If you have a high current going through a highly resistant component, you will generate heat energy.
Joule’s first law:
Q = I squared ⋅ R ⋅ t
where Q is energy in joules, I is current in amps, R is resistance in ohms and t is time in seconds.

To figure out how many joules you need, use the following formula:

Q = cp x m x dT
where Q is energy in kilojoules, cp is specific heat in kilojoules/(kilograms x Kelvin), m is mass in grams and dT is temperature difference between before and after heating.

However, even after giving you all these formulas to work with, I suggest you get a hot plate or something, just for safety reasons.

dabbler's avatar

@28lorelei Good info !

Most common metals that aren’t made to be heating elements have too low resistance.
“car battery to a segment of chain link fence” Chain link fence is Not appropriate for this application. You will be essentially making a short circuit and drain your power fast without getting anything done. Your battery may explode from the extremely rapid discharge.

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