Badmovies.org Forum

Seems the oil companies like that hot gasoline in the summer because they're getting an extra 2.4billion a year from it.  In Canada they require the pumps be able to adjust for the cold temperature gas because that cuts into their profits.

This is an old story, but it's funny that it's been taken to court and Congress and nobody has done anything about it and most people know nothing about it.


http://blogs.abcnews.com/theblotter/2006/12/motorists_were_.html

Underground storage tanks largely eliminate the temperature fluctuations this is based on.  The temperature difference required to see a noticeable effect is actually quite large.  A friend of mine had to do the calculations on this for his PChem class when he was an undergraduate student back in the 80's.

But hey, Americans rarely let facts stand in the way of some good old fashioned sensationalism and jumping to conclusions.

You are correct Ulthar ...

The one thing it effects most is propane, the summer fill of LP is rarely a bargain as LP can expand as much as 5%+ in ABOVE ground tanks. I have a 1500 gallon tank and I always fill mine at the end of winter, and the amount in the tank increases by as much at 5%-7% in warmer weather. I filled mine in March to 75% and now even after some use it's at 82% due to the warming weather. This is why propane tanks are painted white or silver most of the time.

Decidedly true. 

Who knows how tanks under gas stations may warm up, particularly if not full, plus they're often under black asphalt absorbing and radiating heat, and the pumping process will introduce oxygen - hot air - into the gasoline, and who knows how warm those black rubber hoses get absorbing that radiant heat energy all day long...?   :teddyr:  I will say I have noticed, particularly on warm days, evaporation at the pump... you can see it and smell it. 

The issue is not evaporation...it's the density change as the temperature changes.  Do the calculations on how much the density of gasoline changes even over 50 degrees (the pumps are calibrated for delivery at 60-ish degrees) and you'll find it's actually quite small.

So, even at 110 degrees F, the delivery volume is not much different.

Evaporation is evidence of density change. 

Ah...no.  Something can evaporate without a change of density, and likewise, something's density can change with no evaporation.

Two completely different things. Density is a property of a substance at a given set of state variables, whereas evaporation is a Second Law process.

The two have absolutely nothing to do with each other.

My reference is merely the presence of heat.