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From: grege@gold.gvg.tek.com (Greg Ebert)
Newsgroups: comp.sys.ibm.pc.misc,sci.electronics
Subject: Re: Peltier effect device
Keywords: cooling
Message-ID: <1804@gold.gvg.tek.com>
Date: 14 Dec 90 23:35:58 GMT
References: <1990Dec14.213730.10078@spool.cs.wisc.edu>
Followup-To: comp.sys.ibm.pc.misc
Organization: Grass Valley Group, Grass Valley, CA
Lines: 45

In article <1990Dec14.213730.10078@spool.cs.wisc.edu> peng@chaource.cs.wisc.edu (PENG) writes:
>I hope this has not been asked before.  On the December issue of Byte (p.132),
>there is a short article on an interesting cooling device, which can be
>mounted on a CPU and is able to cool the chip down to 0 degree centigrade.
>This device, according to Byte, is a Peltier effect device, which is
>"a thermoelectric cooling system based on the principle that passing a current
>between two physically connected, dissimilar materials produces cooling on one
>side and heat on the other."  I am not quite sure if I know what this
>sentense is talking about.  Can someone knowledgeable elaborate this a little
>bit?
>
>-peng
>
>BTW, in case you are interested, this device is used to push the 486 to 50Mhz.
>I am not sure what the 486 is originally rated?  (33Mhz?)
>-- 

The device is manufactured by Velox Computer Technology, and sells for ~$150
in quantities. See the Article in EDN (Dec 6. , 1990).

The Peltier Effect is significant in an Antimony/Bismuth junction. The process
is reversible: you can measure an emf when the junction is heated (its a few
millivolts), or if a potential is applied across the junction, electrons
will absorb (thermal) energy while traversing the junction. I know zilch about
solid-state physics, but I think it's the result of differing work-functions
of the 2 materials; ie, there is an 'energy gap' at the junction, and the
electrons with sufficient thermal energy can cross the gap and get whisked
away because of the externally applied emf. As one thermally active electron
leaves town, another follows behind which results in a net flux of electrons
with higher thermal energy away from the junction, hence cooling is
observed.

Add a bunch of these together and you can soak-up a few watts of heat.

BUT, before all of you go charging out to by one of these electric ice cubes
and a crystal, be aware that the logic surrounding to CPU probably wont
be able to run at 50Mhz (well, actually 100Mhz).

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