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In article ,
wrote:
Joseph Meehan wrote:

Morning is the best time... the gas is a little cooler and you get
a little more for your money.

You might be surprised to discover how little :-)

How much would you save if a 10K gallon tank lives in 55 F soil and the
air temp above it drops from 34 F in the afternoon to 26 F in the morning?

Actually I remember some little scandal several years ago, when gasoline
that used to be 60 degrees F when delivered was 76 degrees F when
delivered. I know it was something like this, although I may not remember
exactly the temperature figures. I believe I saw it in the Philadelphia
Inquirer.

I now look at "Cubical Expansion of Liquids", CRC Handbook, page 2284 in
the 43rd edition. Pentane is said there to be .001608, and petroleum
(density .8467) according to that source gets .000955. I suspect
gasoline, although it varies, is probably usually not far from at least
one of these - although I suspect lower than the figure for pentane. This
is volumetric coefficient per degree C of thermal expansion.
Looks like 16 degrees F could make a difference of not far from 1 percent.

The way the newspaper story made it out, it appeared to be a scam by the
refinery to deliver less gasoline to gas stations per gallon that they
were paying for.

Now, as for temperature variations in an underground tank: I suspect
that's substantially less than the variation in air temperature throughout
the day. But I don't have any figures for that one. (On an average day
in Philadelphia, the early morning low temperature is 9-11 degrees C
cooler than the afternoon high temperature, depending on the time of year.)

- Don Klipstein )