managing 17 kW heat dissipation (was AI substrate blah blah)

From: Eugene Leitl (eugene.leitl@lrz.uni-muenchen.de)
Date: Fri Aug 06 1999 - 09:57:19 MDT


I don't think 17 kW in a comparatively small volume is that difficult
to dissipate. For one, there are no hot spots. We're talking about 4 W
peak dissipated over a 27 mm x 27 mm surface as atomic unit. The chips
are glued to perforated (to interconnect the layers, unfortunately the
designers used 8 bit wide links instead of 1 GBit serial ones) sheet
copper with some distance in between. I would think the chips would be
perfectly happy to operate ~60 deg C, this should be manageable with a
pretty strong airflow as the geometry is already strongly suggestive
of a radiator. Alternatively, we can incorporate cooling channels into
sheet copper and carry the heat away by liquid, which then can be
dissipated by a large radiator elsewhere.

Alternative solution would be setting the CPU-studded copper sheets
vertically into ~60 deg C boiling point fluorocarbon (ozone layer? Who
needs the ozone layer!?). We would have excellent convection, and the
heat would be carried away by evaporation enthalpy. It would
condensate elsewhere, preferably in a large radiator which could be
cooled passively. Of course we could simply use the heat to prepare
hot water in the building, resulting in a slight plus instead of a big
minus on the air conditioning bill.

The chiefest trouble is making an efficient power source (2.2 and 3.3
V) for that beastie. I guess the power source would dissipate at least
as much as the CPU box itself. Then there is the small matter of
interfacing a disk array/RAM bank to the beastie (could be handled by
a Beowulf, though).



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