[Hardware] The market of ASICs (One GigaKey / Second?)

jbass at dmsd.com jbass at dmsd.com
Wed Aug 11 17:34:05 EDT 2004


Elektron <elektron_rc5 at yahoo.ca> writes:
> It would probably melt (since that's about the cooling capacity of 10 
> big air conditioners, but I'm not sure if you mean 17.5 KW). Depending 
> on the power consumption for one chip, the biggest problem could be 
> getting the heat off the chips before they melt.

Specific heat of air is very low, and coupling to it as a coolant requires
a LOT of energy from the velocity squared component of the problem.

17.5KW/hr is about 15 million calories per hour, or about 4 kilocalories/min.
If we allow a 4C rise in coolant from input to output of the processor
stack, then we need 1 kilogram/min of water, which is about 132lbs/min,
or rougly 16 gallons/min of water as a coolant at room temps. If chilled
water is available, it takes considerably less.

On the other hand, 65KW/hr which is closer to the machines power requirement
if the ZBT/SDRAM and processors are also used, becomes nearly an unmanageable
amount of air movement for a 1 cubic foot processor arrary. Chilled water
handles the problem without any problem.

I'm thinking about burying a thermal sink to heat/cool the house anyway, this
just gets incorporated into it. A freon water/water heat pump is pretty practical
these days, and doesn't have all the losses of pumping huge volumes of high
volocity air.

John


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