Heat pipes? - copper

[alvin at Mail.Linux-Consulting.com]

hi ya bari

> > Part of the reason that you can't find it may be your spelling of it. I
> > couldn't remember the spelling either and had to work it back and forth a
> > bit. You should be able to still get it and I think the price is around $500
> > a gallon.

too much ????

might as well use car antifreeze for $6.oo /gallon ???

both fluorinert and car antifreeze would need a fairly decent sealed
cooling environment... easier to get copper pipes for the antifreeze ???
 
> >>> 
> >>> am thinking of solving cpu heat problems too...
> >>> for p4 and amd in 1Us..
> >>> - add copper to the base of the aluminum heatsink ...
> 
> Copper is a better conductor of heat than aluminum and a bit pricier... 
> why not just add more surface area to your aluminum heat sinks or 
> increase the amount of forced convection across the surface for the same 
> effect at lower cost?

extruded aluminum is terrible heat conductor but very cheap to make
and good enough for slower p3-cpu

an aluminum block that is cut is "lot better" heat conductor as its
molecules are relatively intact ... according to those heatsink
manufacturers .. just a few cents more to cut than to extrude ...
but when making millions of heatsinks units...guess it adds up...

our own tests of good heatsink and extruded heatsinks confirms that
statement ...changing the heatsink only...and watch the cpu temp change

and the surface smaller the area of the heatsink... the cooler our cpus
running....since those itty bitty cans can only blow so much air across
the hot heat sink fins... 

increasing surface area of the heatsink just makes your small 40mm fan
have to cool a bigger/hotter piece of metal than trying to cool 0.25"
square cpu/die

> >>> - get a liquid cooled heatsink - copper pipes with antifreeze
> >>> ( like a radiator ) --  seems like a fun project
> >>> 
> >>> - heat pipes are expensive ?? ..as is peltier cooling
> >>> 
> 
> The least expensive approach to cooling P4s and Athlons in 1Us is by 
> just using aluminum extrusions for heat sinks that form the top of the 
> enclosures and using forced convection across the the units. We're using 
> some profiles now that are only 0.08 - 0.11 degC/W at 100 CFM. These 
> would allow the use of a P4 in an ambient of up to 68 deg C.... but I 
> wouldn't want to be in that room :-)

isnt 68deg still on the high side ??? ....

some of ofour cpu temp measurements was around 30-35 range...hitting
up to  40 or so when runnign heavy loads during the day...
	- the bigger the heatsink got... the hotter the cpu ran too
	cause the itty bitty fans was not good enough ...

all our stuff is in 1Us...

we also blow air across the cpu from the outside...cpu is adjacent
to the 1U chassis wall .. makes for a very happy cpu...

c ya
alvin
http://www.Linux-1U.net

> >>> c ya
> >>> alvin
> >>> http://www.Linux-1U.net
> >>> 
> >>> 
> >>> On Mon, 21 May 2001, Donald B. Kinghorn wrote:
> >>> 
> >>> 
> >>>> Has anyone looked into using heat pipes for cpu cooling ... surely
> >>>> someone has done this(?)
> >>>> 
> We have been using them for years and they work great at moving heat 
> from the surface of a processor inside an enclosure with minimal airflow 
> to an area outside the enclosure with plenty of natural or forced 
> convection. You'll find that many laptops use heat pipes for heat 
> transfer from the cpu to the rear of the enclosure.
> 
> Bari
> 
> 
> 
> 
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