"Frank" <Frank@hotmail.com> wrote:
>sorry for top posting but your text is long, but very useful.
>I'll need a 120mm fan, space is plenty for 2 fans and my definition of quiet
>is like having all your pc fans off, boot into bios and all you can barely
>hear are the HD and the PSU. If temps are below 50-55C without fans, I'll be
>glad, but if not, i would have a 120mm fan turn very slowly just to keep it
>below that. But when I need to, I want a fan that will push enough cfm to
>pass accross my rad which is a good 1.5in think. I was planing on using a
>simple 3 postition switch with resistors to control the 1-2 fans. I could
>have Off - Mid speed (7V) - high speed(12V).
>I also used an aluminium reservoir, (
>http://www.noiseisolator.com/wt-tb.htm ) to help in cooling. I'll pass the
>water from pump-cpu-chipset-vga-reservoir-rad-pump. That way, the biggest
>heat will be absorb by the reservoir and hopefully, I'll manage to run my pc
>at stock speeds with no fans.

You can literally calculate the amount of heat that can be
stored in any given sized reservoir of water, and from that you
can calculate just exactly how long it will take to raise the
temperature of your reservoir to any given point at which you
estimate that the cpu will not get sufficient cooling. (And,
once you get it installed you can measure that very easily.)

If there is no air movement across the radiator, the reservoir
is not going to shed any of the heat (or, at least very little
of it). Hence it is not a matter of if it will rise to a
temperature where your cpu is not getting sufficient cooling,
but just a question of how long. (Note that it is just a bigger
heat sink than is a regular air cooled heat sink. The air
cooled device is so small that with no fan it only takes seconds
to overheat the cpu. With a water reservoir, it takes minutes
or even hours if it is large enough... but it still overheats.)

Obviously if you have a relatively small reservoir (say 1
quart), it won't take long to heat it up, and might take nearly
forever to cool it off! On the other hand, with a large
reservoir (say 5 gallons) it will take quite a while to heat
up... but it literally will /never/ cool off (in the same week
anyway!).

>I guess im better off to start off with no fans at all, see how it goes and

Because of the above, it would seem there is no point in trying
to start off with no fans at all, unless you have some other
arrangement to remove heat from the reservoir. It sounds as if
you are talking about a relatively small reservoir and a system
entirely enclosed in the computer case, which suggests that it
will perhaps take many minutes to heat up, and many hours to
cool off again. Which is probably not an acceptable recycle
time. And if you do have an external reservoir that is larger,
it extends both times... and is still not an acceptable recycle
time! (Imagine a 4 hour game session, and then having to wait 2
days while your water tank cools off!)

>try to use a temporary fan just to see how cool i can get it and see if a
>really need these high cfm. I might be satisfied with a panaflo M but like
>you said, some say its still loud even at low rpm. Ill see if can have a
>shop around hear have me listen to the noise it make just to see. When
>gaming, noise would not really be a problem, but when idle or like watching
>a movie, I need dead silence.
>(sigh) Not easy to have both silence and performance.

The problem is that you need a way to *know* what is going on!
That means temperature probes in cooling system. The probe in
the cpu is fine, but it doesn't tell you what the status of the
reservoir is, and hence won't give you a clue about what the fan
needs to be doing.

I suppose you could just put a little battery operated digital
indoor/outdoor thermometer probe in the water tank, and use that
to decide when to turn the fan off and on manually. But beyond
that, the effort that it takes to automatically monitor
temperatures makes it well past the point where it is easy
enough to just add automatic fan control, based on the
temperatures.

I previously posted a URL to the Crystalfontz CF633 unit which
will do all of what you need. The temperature probes are a
couple bucks each, and it will handle 32 of them. It has
controllers for 4 fans, and they can also be used for things
like turning on and off a relay to switch something on and off,
or the "fan speed monitor" can be used to monitor a liquid flow
meter instead.

Basically these devices allow you to have a fully metered
cooling system. It is possible to measure coolant temperature
in the reservoir, after the cpu waterblock, and after the
radiator, and air temperatures in the case and on each side of
the radiator, plus outside and room temperature too if you want!

It has a watchdog function, hence if something fails, you can
either have it shutdown your computer (wise if it is left on and
unattended) or have it notify you by other means (console bell,
whatever).

But the main thing it will do is keep the fan at the lowest
noise level suitable to the load on the cooling system! Which
is to say, it will be as quiet as it can be for whatever you are
doing with the computer at the time. If your reservoir and/or
the radiator are large enough, it is probable that the fan would
never have to run fast enough to create excessive noise; but
what the fan would do is continue running after your game
session has ended, in order to bring the reservoir temperature
back down to "normal", thus giving you quick "cycle times"
without ever needing maximum fan speed.

And, if you get any fun at all out of messing with a water
cooling system, that would make it several times *more fun*!!!
(And if you don't, the best advice I can give you is to stay
*way* away from a water cooling system! I've dealt with them on
commercial equipment for years, and it is always a high
maintenance item.)

--
Floyd L. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@apaflo.com