"CJT" replied:
Timothy Daniels asked:
I'm not proposing any in particular, but you seemed to be saying
you didn't like coolers that blow inward at the top of the case.
Air forced into the case anywhere will increase the air pressure
inside the case, reducing the "suction" that draws air in at other
points. If low pressure (caused by an exhaust fan somewhere) is
not needed for this intake of air, there's no problem. But if "suction"
*is* required - which is normally the situation - blowing air into
the case reduces it and the air that would normally be drawn in by
suction is reduced. In most cases that I've seen, this usually means
that the primary hard drive gets less air flow. One solution is to
make *all* air intake done by blowing into the case.
Whatever is done, though, the goal is to make the air flow over all
the warm components, from one corner of the case to the other,
with the hottest components at the top and downwind near the exit.
This depends on a pressure gradient (i.e. slope) to cause the flow -
highest pressure at the intake, lowest pressure at the exhaust. You
can maintain this pressure gradient by blowing in at the upwind point,
but there has to be a good seal between the fan and the case and
there better not be other open holes in the case that would relieve
the over-pressure - or it would be like pushing on a string, with the
air escaping out the open holes and not flowing all the way to the
proper exit.
In the situation where air is blown into the case near the top, the
gradient is disrupted by raising the pressure at that point (usually
near the power supply intake) - reducing the "suction" - and all
flow is reduced upwind of that point, and the primary hard drive
is usually right at the head of that flow.
The ideal situation would probably be blowing in at the bottom front,
and sucking out at the top back. But there again, sucking or blowing
at any intermediate point would disrupt the gradient, and more sucking
or blowing at the extreme points (front bottom/rear top) would have
to be done to compensate for it. How much engineering do you want
to do?
*TimDaniels*