peter wrote:
> I had no idea it been that long in development..........I would still like
> to see some tests...
> I would think it would beat a H20 cooled unit...
> as for the start up problem.. who says there would be??
> I would assume that the Magnetic Pump would keep circulating the liquid
> metal ...
> I also would assume that the liquid metal would stay liquid until a
> fairly low(sub zero) temp
> One would think that the metal would be capable of removing more heat
> from the CPU and that
> heat would be absorbed by the radiator and removed by the fan(s)
> Whether it be more efficient than Water or Air Cooled Heatpipes only a
> Test can determine
> I never shut down anyways
>
> peter
>
The heat of vaporization is a very effective mechanism for
heat transport. That is what a heatpipe relies on. This
diagram illustrates the reason graphically (although this is
for Zinc). The large vertical rise, at the boiling point, shows
the energy input needed to turn the material into a vapor. And riding
up and down that large vertical line, is where a heatpipe operates.
A heatpipe, in fact, is hundreds of times more effective than a
solid piece of copper of the same size. It is the same cycle used
by air conditioning (heat of vaporization).
http://upload.wikimedia.org/wikipedi...2Cl%2Cg%29.PNG
The liquid metal device, on the other hand, rides the gently sloped
diagonal in the middle of the chart. At least in the case of Zinc,
that would not be as effective a means of transporting heat.
The heatpipe solution is "self propelled", in the sense that
the vapor will transport itself to the cool end of the tube
and condense. Flow of the condensed liquid is aided by
capillary action on the inside surface of the heatpipe,
sometimes provided by a sintered finish on the inside of
the pipe.
http://en.wikipedia.org/wiki/Sintering
http://en.wikipedia.org/wiki/Heatpipe
I suppose one advantage of a liquid metal, might be an
extended operating range temperature-wise.
The fin part of both cooling solutions would compare on an
equal footing, and the cooler with the most fin area and
good airflow past the fins, would win at that level. The reason
for any transport mechanism, is to more effectively couple
heat into the fins. In heatsinks that lack a transport mechanism
(other than conduction), usually the very end of the fin is
virtually useless, as the tnermal resistance of the (thin) fin
prevents the ends from becoming very hot. Making a fin thicker
isn't optimal, because then there is less surface area per
unit volume of fins.
Paul
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