Joe
You been in the moonshine again. Or you have way to much time on your hands
and DrMayf is usually the one that throws this stuff out.
Glen
----- Original Message -----
From: "Joe Lance" <jolylance@earthlink.net>
To: "LAND-SPEED @ AUTOX.TEAM .NET" <land-speed@autox.team.net>
Sent: Sunday, January 08, 2006 1:39 PM
Subject: NON-LSR, DAYTIME RUNNING LIGHTS
> List:
>
>
> Daytime running lights on cars and trucks consume 15,000 MW of electricity
> as
> related by some letter writer in ME magazine. 15,000 MW is enough to power
> most of New York state. When I told this to a group, I got arguments that
> the
> lights were "free" if you were driving the car anyway. But you still need
> to
> burn gasoline to power the lights.
>
> Given 100 watts needed to power the daytime running lights on one vehicle
> and
> assuming 150 million cars and trucks, you get 15,000 MW.
>
> The alternator/battery "turn-around" efficiency which is comprised of the
> alternator efficiency (high by itself), conversion from AC to DC, storage
> in
> the battery, and discharge of the battery, is about 30% when all this
> stuff is
> considered. However, since at least part of the time the electricity goes
> directly to the headlamps without being cycled through the battery, I will
> neglect the "turn-around" efficiency (or inefficiency).
>
> Assume a 20% efficiency for conversion of gasoline to alternator
> electrical
> output. Also assume the daytime running lights operate for an average of 2
> hours per day (including commercial vehicles)
>
> So then: 15,000 MW x 2 hrs/0.2 = 150,000 MW-HRS per day which is 513 x
> 10^9
> Btu per day.
>
> Since gasoline is 125,000 Btu/gallon, operating the daytime running lights
> consume 4 million gallons of gasoline per day.
> Or 1.1% of the total gasoline consumed in the U.S. (360 million gal/day).
>
> Four million gallons of gasoline is about 98,000 "barrels", So, if we get
> only
> about 20% (wild ass guess) of gasoline from refining a barrel of crude
> oil,
> then the daytime running lights "consume" about 500,000 barrels of
> imported
> oil per day. So, are the daytime running lights worth this cost?
>
> Why am I wasting time on this? Because this kind of mental exercise is
> supposed to ward off Alzheimer's and I can't have any real fun until after
> dark anyway.
>
> Lance
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