Alright everyone, Welcome back to Cody's lab. So, paraffin wax is an excellent way to store thermal energy
In fact, it was used on the lunar rover
to store excess heat thus, cooling the electronics and stuff.
So what I'm doing here is I'm melting down a bunch of
used candles that I got from the thrift store for about 50 cents a pound
and I'm gonna use this melted wax, which is
arguably impure, for use as heat storage by which I mean
I want to see what happens if I use it to fill a hot water bottle.
Will the wax stay warm longer than water will?
The heat capacity of liquid paraffin and indeed solid paraffin is a little bit less than water and
the heat of fusion is less than water as well.
What wax is really got going for it is the fact that the heat of fusion is released
at a temperature that is above my body temperature, like
water releases a bunch of heat as it freezes. That's why it feels warm during a snowstorm,
relatively warm, 32°F, 0°C,
you know, the temperature drops down as the heat is removed and then it holds steady during the fusion
as it's solidifying and then it drops farther
so it holds the temperature at its freezing point. Now, the freezing point of wax
feels warm so basically this will stay at the same warm temperature for a long time whereas water would drop down constantly.
So I've let the wax cool off, so it's just above its melting point, that way it's not going to be too hot for the bottle.
Let's just put it in there.
Hopefully the wax doesn't dissolve the rubber.
Initially when I got these bottles. I thought they're made out of silicone
But they are actually made out of a natural rubber, which might be susceptible to chemical attack.
We'll find out.
Alright, so now, I've got two about two liters of liquid wax inside of this here bottle
I'm gonna put this down inside of a pot that's got water in it, which is hot but not boiling
Yeah, this is so I can make one that has got water only
come up to the same temperature.
So, let's let this sit in this pot for
probably over half an hour just to make sure that the one with water is equalized to the wax.
So I've taken both of the water bottles out of the pot, put them into their cute little cozies here
and I've placed a thermometer, an
identical thermometer into each of them so the probe is sitting right here inside of the cozy.
I think, uh
That one's the water, and this one over here is the wax so
let's set up a time-lapse see how these do. We're starting at 7 o'clock.
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Okay, so here we are, what is that, almost 16 hours later?
The water is
yeah, that's the room temperature right there
and then the wax is still just a little bit above room temperature
So yeah, the wax does stay warmer longer. That is cool.
In fact it did so better than I thought it would.
I know there's a little bit more energy here than there was in the water
but not a whole lot more. I think one of the main reasons why I stayed warmer longer is the wax, like, self insulates itself.
I guess the outer part of the wax cools
it creates an insulating barrier, you know, oils are actually pretty good insulators of heat and
you know, you don't get that convection cooling it off.
So the water cooled off very rapidly, the temperature went [imitates glissando]
The wax kind of went down, and then stayed at the same temperature before finally starting to go down so yeah, that's a pretty good result.
So I've done a little bit more experimenting with this, and I've decided that just putting the wax in a two-liter bottle works
just as well if not better.
These are certainly cheaper than the hot water bottles
You know, you can see into it, so you know when the wax is melted.
This rubber thing you can't see through.
The material is actually a bit more resistant to the wax I would think.
Tougher which is good because the cat took a liking to these.
Ya killing it bud? Ya killing it?
Ya get it?
[Cat's collar jingles around]
The hot water bottle does do well
but, you know, the cat did bite through one so
there you go, he can't really get his mouth on the
2-liter bottle, but he can get it on the ... right like there. See? They're much easier to bite that.
Yeah, well, I continue to do experiments with this, but you know?
I'll just stick one of these you know, after the wax is melted, stick this in a sock and will keep me warm for about 12 hours.
Hope you enjoyed. I'll see you next time.
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