Date:         Fri, 30 Nov 2012 17:13:06 -0600
Reply-To:     mcneely4@COX.NET
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Dave Mcneely <mcneely4@COX.NET>
Subject:      Re: Gas consumption higher in winter?
Comments: To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
In-Reply-To:  <BAY152-ds182A2761E0ECB3705D5BEA0430@phx.gbl>
Content-Type: text/plain; charset=utf-8

---- Dennis Haynes <d23haynes57@HOTMAIL.COM> wrote: 
> In many marine and industrial application fuel consumption is often rated by
> pounds/hour or a metric equivalent.
> 

Measuring fuel by weight makes more sense.  Then we would be closer to a constant value from place to place, though weight does vary according to distance to the center of the earth.  So, a given mass weighs more at the poles than at the equator, and at sea level compared to a high altitude (but not much more).  mcneely

> Dennis 
> 
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> Marc Perdue
> Sent: Friday, November 30, 2012 5:11 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: Gas consumption higher in winter?
> 
> 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
> >

--
David McNeely