Limited cooling space

[Gary Derian]

The coffee mug experiment does not duplicate the radiator conditions.  It is
no surprise that water that travels through a few feet of hose and a spray
head is cooler than water that does not.  In the radiator, the average
residence time is the same each way, 3x speed for 3x distance vs. 1x speed
for 1x distance.

Wouldn't the OEM's build radiators this way if it were better?  Of course
they would make it smaller to save money for the same cooling.

Gary Derian <gderian at oh.verio.com>


> > The way I see it, the coolant now "sees" a radiator that is 1/3 as high
and
> > 3 times longer.  Why does this cool better than normal.  The log delta T
is
> > the same, no?  Is it a flow turbulence thing?  That is the only change I
> > see.
>
> Here would be my <cough> guess...
>
> If you increase the width of the radiator, the coolant has to move
> further to reach the other side and be sucked back into the system,
> therefore its exposed to the ambient (and hopefully cooler) air
> temperature, which reduces the temperature of the coolant going back
> in.
>
> While my dilbert-cube-mates think I'm insane, I just tried something
> that you can do that will illustrate the point.
>
> Run the hot water on your faucet for a few minutes, until the
> temperature is constant.  Stick a thermometer into a coffee mug, then
> fill it with hot water.  Record temperature.
>
> Then, using a second thermometer, or cool off the first one to room
> temperature, repeat the experiment, however use the hose with the
> spray gun, which typically has 5-6 feet of hose under it.  The
> temperature in the mug is consistantly 5-6 degrees colder.  I did this
> 3 times to make sure.
>
> Longer hose, more distance traveled, more energy (heat) lost or
> radiated into "space".
>
> --
>
> Frederic Breitwieser
> Bridgeport CT 06606
>
> 1993 Supercharged Lincoln Continental
> 1989 HWMMV w/turbocharged 500cid Caddy
> 1975 Dodge D200 Club Cab soon to have 431 stroker + turbos
> 2000 (I hope) Buick GTP (Mid-Engined Sports Car)