Maker Pro
Maker Pro

Current rating of an RJ45 connection

R

rickman

Jan 1, 1970
0
My father painted his stock car's radiator silver one time. From that
point on, the engine overheated badly and he could not understand why (I
was not old enough at the time to be of any help).

After several weeks of trying to work out the problem he eventually gave
up and discarded that radiator and put a different "black" one in. The
problem then completely vanished. It wasn't until years later, when I
took thermodynamics in high school, that I realized why a black radiator
works better for dissipating heat.

But what I don't understand is why air conditioning heat exchangers are
all aluminum in color. Why do you not see black A/C heat exchanger
coils? Even on your car, your radiator will be black, but the A/C heat
exchanger in front of it (which also must dissipate heat) is left an
aluminum (no paint) color.

Would the A/C heat exchanger work better if it were also painted a thin
layer of black paint? I've never had the guts to try it on my home's
central air coils. :)

Warren.

The radiator should not have worked differently because it was silver
other than the fact that it was painted and so the spaces between the
fins were smaller and the air flow more restricted. Radiators, contrary
to their name, don't really do much radiating heat. The heat is
conducted to the air flowing over them. That is why they have the thin
fins with lots of surface area. If they really radiated the heat, they
would just plain be large, likely covering the entire surface of the car.

That explains why the aluminum heat exchanger works just fine, color
doesn't matter when you are conducting the heat away.

Rick
 
J

Joerg

Jan 1, 1970
0
rickman said:
The radiator should not have worked differently because it was silver
other than the fact that it was painted and so the spaces between the
fins were smaller and the air flow more restricted. Radiators, contrary
to their name, don't really do much radiating heat. The heat is
conducted to the air flowing over them. That is why they have the thin
fins with lots of surface area. If they really radiated the heat, they
would just plain be large, likely covering the entire surface of the car.

That explains why the aluminum heat exchanger works just fine, color
doesn't matter when you are conducting the heat away.

I also suspect that the silver paint Warren's dad used was the usual
thick and "soupy" type metallic paint. That stuff could add an
insulation layer where you really didn't want one.

In my youthful days in the 80's I used that kind of paint for my
electronics projects. It looked cool (well, for the 80's it did) and it
was so popular that you could always find leftovers or small can on sale.
 
J

Jasen Betts

Jan 1, 1970
0
On 12-08-30 4:19 PM, Joerg wrote:
My father painted his stock car's radiator silver one time. From that
point on, the engine overheated badly and he could not understand why (I
was not old enough at the time to be of any help).

After several weeks of trying to work out the problem he eventually gave
up and discarded that radiator and put a different "black" one in. The
problem then completely vanished. It wasn't until years later, when I
took thermodynamics in high school, that I realized why a black radiator
works better for dissipating heat.

mainly it was the paint insulating the fins from the air. the black
lacquer used on old radiators was to stop them from oxidising,
But what I don't understand is why air conditioning heat exchangers are
all aluminum in color. Why do you not see black A/C heat exchanger
coils?

because copper is too expesive,
Even on your car,

I once has a car with an unpainted aluminium rdiator core, this was
stock, not a modification.
Would the A/C heat exchanger work better if it were also painted a thin
layer of black paint? I've never had the guts to try it on my home's
central air coils. :)

if it was really thin, like black anodize, maybe
..
 
W

Warren

Jan 1, 1970
0
I suppose you're right.
I also suspect that the silver paint Warren's dad used was the usual
thick and "soupy" type metallic paint. That stuff could add an
insulation layer where you really didn't want one.

It could be- it may have been thicker than it should have been (I
couldn't tell you now what kind of paint it was).

Copper of course would need some kind of coating to keep the thing
from corroding, whereas I suppose the aluminum is prolly not so
prone, depending upon the alloy used.

Warren.
 
Top