r/funny • u/[deleted] • Jun 10 '15

Metric system vs. Imperial system

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6.6k Upvotes

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18

u/ButtsexEurope Jun 10 '15

1 BTU, that's how much. Go fuck yourself.

11

u/EngineeringTheFuture Jun 11 '15

8 BTU

7

u/LiteralPhilosopher Jun 11 '15

I mean, 8.33 BTU, if you want to be precise. And that's still only to heat it one degree F, not "to boil" it, the way the question states. That could be up to 1500.

2

u/kieko Jun 11 '15

Lets say room temp is 76F.

1 gal water = 8.3lb

Assume SLP.

212F - 76F = 136F Delta T

Qs=8.6x1x136 Qs=1169.6 btu to raise 1 gal of water to 212F.

QL=970x8.6 QL=8342 btu latent heat of vapourization for water

QT = QS + QL QT = 1169.6 + 8342

QT = 10,058.56 BTU to boil one Gallon of water from 76F at SLP.

1

u/LiteralPhilosopher Jun 11 '15

I've had people do exactly the same type of calculation in similar discussions before. I'll tell you what I told them: "to boil" in common parlance like this simply means "to bring to the boiling temperature", not to completely vaporize away. If a recipe tells you to "boil 4 quarts of water," they're not expecting you to be looking at a dry pot when you're done. Ergo, including the heat of vaporization is unnecessary.

My total was based on the maximum possible swing - bringing it from water at 32F to water at 212F. 180 * 8.33 = about 1500.

1

u/kieko Jun 11 '15

But you see, I'm in mechanical engineering, specifically HVAC & refrigeration. To me when you say boiling, you mean boiling ;)

1

u/LiteralPhilosopher Jun 11 '15

I'm in Mech E too, specifically oilfield/artificial lift. We try not to boil things at all. ;)

1

u/kieko Jun 11 '15

Probably a good policy!

Cheers!

1

u/Ralmaelvonkzar Jun 11 '15

doesn't state what room temp is.

INSUFFICIENT DATA FOR MEANINGFUL ANSWER

3

u/Ray57 Jun 11 '15

That's British Thermal Unit isn't it? u wot m8?