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