dear vanah-log-o-rhythm
i think this list just became too smart for me
if it continues i may have to reach for my copy of
the soul of the universe
http://adsabs.harvard.edu/full/1940PA.....48..570S
yours

On Sun, Apr 25, 2010 at 1:00 PM, David Beierl <dbeierl@attglobal.net> wrote:

> At 01:22 PM 4/25/2010, Jake de Villiers wrote:
>
>> When approaching the long (15 - 30 minute) second and third gear
>> grades through Eastern Washington and Idaho you'd turn on the fan
>> before the rad got too hot.
>>
>
> Ok, I see the idea.  But do the numbers make sense?
>
> Lessee... at 75 horsepower output and 1/3 efficiency the engine's
> going to be putting out something like 200 kw of waste heat, or 3.4
> kWh per minute.
>
> 18 quarts of 50/50 coolant weighs around 36 lb and has a specific
> heat capacity of roughly 0.85 BTU per lb per deg F at working
> temperature.  So changing the entire coolant by 20F would get you
> 0.85 x 20 x 36 = ~600 BTU, about what a sedentary human throws off in an
> hour.
>
> 600 BTU = ~0.18 kWh.  3.4 kWh x 0.18 x 60 = ~32
>
> So a twenty-degree change in the entire coolant would absorb the
> waste heat of the engine for about thirty two seconds.  I think this
> is conservative since the coolant inside the engine won't be
> participating in this, and because 75 hp may be conservative for
> climbing a steep hill.
>
> Somebody check my numbers.  If this number is anywhere near correct I
> don't think it's worth the hassle.
>
> Yours,
> David
>

--
roger w
From Proverbs:
Under three things the earth trembles, under four it cannot bear up: a
servant who becomes king ...
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