Date:         Fri, 30 Nov 2012 17:10:48 -0500
Reply-To:     Marc Perdue <mcperdue@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Marc Perdue <mcperdue@GMAIL.COM>
Subject:      Re: Gas consumption higher in winter?
In-Reply-To:  <20121130165657.4AMEM.348627.imail@eastrmwml205>
Content-Type: text/plain; charset=ISO-8859-1

Wouldn't they have to heat the gas in the underground storage tanks? The
ground temp usually runs 45-55 degrees F below the frostline . . .


On Fri, Nov 30, 2012 at 4:56 PM, Dave Mcneely <mcneely4@cox.net> wrote:

> ---- OlRivrRat <OlRivrRat@comcast.net> wrote:
> >       This from Wikipedia
>
> Which is in complete agreement with what I said, as is the other site you
> referenced.  But, I did not know that a standard commercial gallon was
> measured at 60 F.  To compensate, the pump would have to measure the
> temperature, and integrate an algorithm to adjust the metered volume to
> what that volume would be if the temperature were 60 F.  Since chips and
> programming are now cheap, that would not be hard to do, but it would add a
> tiny increment to cost.
>
> thanks for the links.  mcneely
> >
> > "The US liquid gallon
> >
> > The US gallon, which is equal to 3.785411784 litres is legally defined
> > as 231 cubic inches.[1] [2] There are four quarts in a gallon, two
> > pints in a quart and sixteen fluid ounces in a pint. In order to
> > overcome the effects of expansion and contraction with temperature
> > when using a gallon to specify a quantity of material for purposes of
> > trade, it is common to define the temperature at which the material
> > will occupy the specified volume. For example, for purposes of trade,
> > the volume of petroleum products[3] and alcoholic beverages[4] are
> > both referenced to 60 °F (16 °C)."
> >
> >       So lets say that the gas you pump is @ 60º in the
> > UndergroundStorageTank, after a short period of time in your GasTank
> > it will adjust to AmbientTemp' so in the Summer it will Expand to More
> > Gal's & in the Winter it will Shrink to Less Gal's.
> >       I started looking into this thanks to Costco (where, until
> recently,
> > I never bought gas) as there is a Sticker on their pumps that states
> > that the Gal' of Gas that they charge you for is 231CuIn as measured
> > by the pump.
> >       This is an interesting PDF ~
> www.nh.gov/agric/news/documents/weights-fuel-temperature.pdf
> >   ~ I stumbled on to it earlier when I Googled "gas pump gallon volume"
> >
> >                                                       ORR ~ DeanB
> >
> >
> >
> > On 30 Nov , 2012, at 12:28 PM, Dave Mcneely wrote:
> >
> > > ---- OlRivrRat <OlRivrRat@COMCAST.NET> wrote:
> > >>         Also keep in mind that the vol' of a
> > >> Gal'OfGasoline @ 80º is 233.7CuIn
> > >>
> > >> & @ 30º it is 227.0CuIn so you actually have less GasByVolume in your
> > >> tank in the Winter
> > >>
> > >> than in the Summer but I haven't really thought through what effect
> > >> that might have on
> > >
> > > Hmmmm........... .  Do you mean that a gallon is not always a
> > > gallon?  Is the gallon you cite a gallon at standard temperature and
> > > pressure (O C,  760 mm Hg) but a bit bigger at warmer temperatures?
> > > Because a gallon is a measure of volume.  The fuel may expand and
> > > shrink, but then it won't be a gallon any more, it'll be something
> > > else.
> > >
> > > Now, if you cited a variable volume for a given mass of fuel (again,
> > > the weight but not the mass could vary depending on where the
> > > measurement was made), then we'd be getting somewhere.  If you want
> > > the same exact amount of fuel regardless of conditions, you need to
> > > deal with mass, so as to have the exact same number of molecules.
> > >
> > > If you put in a gallon of fuel at one temperature, then the stuff
> > > expands as it warms up, there is still no more fuel in the tank, it
> > > just takes up more volume, more than a gallon.  Same if it shrinks,
> > > it now takes up less volume, less than a gallon.  The amount of fuel
> > > does not vary, just the space it occupies.
> > >
> > > If you buy a gallon of fuel that is cold, and another time buy a
> > > gallon of fuel that is warm, the second time you get less fuel.
> > >
> > > All this would suggest that one might get better mileage (miles per
> > > gallon) in winter, since by burning a gallon of fuel, one burns more
> > > fuel, but other variables seem to obviate that.  At least they do
> > > for me, as I get poorer mileage in winter, by subjective judgement,
> > > anyway.  Of course, to be sure, we'd need a controlled experiment
> > > that is probably beyond our ability to design and carry out given
> > > the limitations of available vehicles and ability to control
> > > variables.
> > >
> > > mcneely
> >
>
> --
> David McNeely
>