From: Richard Erlacher <edick_at_idcomm.com>
Date: Wed Nov 17 18:26:33 1999

4" doesn't really make for a "deep" hole. You should be able to do this
with pretty standard drill bits, but cool them and lubricate them. For best
results, use a coarse feed and a relatively slow speed with a very sharp
(best is freshly sharpened for every hole) tool. Drill your holes in a
single stroke, so you won't have to cope with a work-hardened surface. Take
your time.

If you custom machine your heatsink to fit the enclosure it lives in,
fitting it with 1/4" i.d. holes and 1/4" pipe for circulating the liquid
coolant (no FREON or other CFC's...we've got to be ozone-layer-friendly)
you can always put an arbitrarily large exchanger outside in the winter, to
keep the temperature in the circulating fluid somehwere around -100 Celsius.
Remember, what matters is the amount of HEAT you transfer, not the
temperature difference, though the heat flows faster between regions of more
widely differing temperature. You might even find you don't need so large a
delta-T. If you move vast quantities of cold air through a 1 cu. yd.
outdoor heatsink, you could put an array of large peltier coolers there to
heat that heatsink at the expense of the heat carried to it from the
computer in the house. Hopefully you're not trying to be terribly efficient
. . .


-----Original Message-----
From: Aaron Christopher Finney <af-list_at_is1.wfi-inc.com>
To: Discussion re-collecting of classic computers
Date: Wednesday, November 17, 1999 2:42 PM
Subject: Re: E.U.N.U.C.H.

>On Wed, 17 Nov 1999 Philip.Belben_at_pgen.com wrote:
>> Anyway, it seems to me that the way to go is:
>> 1. Peltier chip between CPU and heatsink. Heatsink is a large block of
>> 2. Use a refrigerant cycle similar to a domestic freezer, but connect the
>> refrigerant circuit directly to holes bored in the heatsink block. No
>> intervening water circuit.
>> 3. Of course, keep the refrigerant radiator well away from the system,
>> supply it with plenty of fans...
>> 4. Finally, try not to spill refrigerant if it's one of those chlorinated
>> organics that the environmentalists are always going on about. It won't
do any
>> good (although a discussion of whether it does harm is decidedly
off-topic), and
>> will be well-nigh impossible to replace...
>One issue with copper is the cost. I can buy .5" x 4" aluminum barstock at
>around $2.00 a foot (I'm sure our friends in Europe love these units of
>measurement). It's also relatively easy to bore through with a
>high-quality drill bit if cooled with running water. Also, if I happen to
>screw up and drill through the side I don't cry as much...
>For my current peltier-based setup, I have to use a coldplate against the
>cpu itself because I'm using multiple TECs in the design. After getting
>some help with actually arranging the different variables into a useable
>equation, I was pleasantly surprised to find that the temperatures were
>within +/- 3C of my calculations.
>One last note about using a water-exchanger in this setup (and then I'll
>shut-up, I promise), is that it's nice not to have to worry about cooling
>the inside of the case too! Also, it doesn't sound like a jet-engine
>starting up...the pump is more like the pleasant gurgle of an aquarium.
>So off-topic it hurts,
Received on Wed Nov 17 1999 - 18:26:33 GMT

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