Arthur Hagen said:
Stop listening to Mr. Maynard. The air is heated by five 7200rpm drives on
the way into the case, and is never as cool as 25C. Heck, the ambient room
temperature is never that low. It *is* possible to have something
cooled
by
air become cooler than the ambient temperature, and I described exactly the
principles, as well as examples in my previous post.
I principle yes, in practice NO - the pressure differential is so low that
any cooling effect would be almost immeasuarbly small.
Mr. Maynard, in his usual style, completely disregards what people write
with a short pompous reply that doesn't give ANY kind of evidence. I'm
sorry, but this *is* a normal process of physics, and Mr. Maynard has made
no successful argumentation for *why* it should not apply to heat sinks.
"argumentation" <LOL>
His "dismissal" that "heat flows from warm to cold" (second law of
thermodynamics, atta boy!) seems to indicate that he is unaware that air
that moves IS colder, due to lower pressure. The moment you start moving
the air, the temperature drops.
Balls, air circulates downward on the outer rim of a hurricane and it gets
hotter, not colder. Any wind blowing down a mountainside gets hotter too.
If there is any compressive effect when you move air then it will get
_hotter_ not colder.
If you exhaust air from a heatsink then the air withing the heatsink will be
at slightly lower pressure than ambient but the pressure differential will
be so low that any temperature differential will be close to immeasurably
small.
It may sound counter-intuitive, but the
preservation of energy still applies -- the energy that the air loses by
becoming colder, it gains as kinetic energy. So when the ambient
temperature inside the case is 34C, the air moved by the CPU fan might very
well be 30C, which cools the heat sink assembly to 33C.
In addition, there's multiple other thermodynamic forces at play here --
including moisture evaporation
Now this bit is utter bullshit - the heatsink will be well above dewpoint
thus dry as a bone in a desert. You would have to continuously spray it
with water to keep it wet, or don't your sheets dry on a windy day..?
Your temperatures are just plain wrong IMNSHO - hunt out where the sensor
for the 'system' temp is on your motherboard & do a comparison with an
accurately calibrated thermometer. (As I do, I use the difference to
recalibrate MBM5.) You'll very likely find that yours isn't representaive
of true system temperature, they rarely are.
and kinetic energy transfer. Both should,
howeer, be minimal.
A P4 will, when idle, produce very little heat indeed, and a good
heatsink
/
fan combination is quite capable of cooling most of it to ambient case
temperature or lower.
Utter rubbish.................
PLONK
[UK]_Nick...
