[Tfug] peltier?

[Sean Warburton]

oh, I never even though of sticking a heatsink on the resivour. Good idea. I
will do that and run a CPU burn-in test for a couple hours and watch the
temp. I never watched the temp of the coolant, but I felt the tubes, and
they were hot, so it was not cooling off quick enough to be of any use. Ill
let you know how the heatsink idea works. Thanks,
     Sean


On 9/28/07, John Gruenenfelder <johng at as.arizona.edu> wrote:
>
> On Thu, Sep 27, 2007 at 05:09:25PM -0700, Sean Warburton wrote:
> >
> >Now, I heard of an interesting physical property called the peltier
> effect,
> >which is (as I understand it) the direct conversion of electricity into
> >temperature changes.  This makes sense, because  when I overclock my CPU,
> I
> >force more power than normal into it, and a higher temperature is
> achieved.
> >This system must work the other way, where it can make things cold. Some
> >research yielded a product that looks like a ceramic plate and one side
> gets
> >cold while the other gets hot when a current is applied. Furthermore, the
> >temperature difference is dependent on the ambient temperature, right?
>
> Actually, your CPU generates heat as a waste product when transistors (all
> the
> many millions of them in the chip) switch off and on and some due to
> resistance in the tiny wires.  The peltier effect is fundamentally
> different,
> but in broad terms, yes, you supply a current and the plate starts
> cooling.
>
> But, there are a number of reasons why you don't see them in PCs very
> often.
> One is that they are very inefficient, no more than 10%, so you're wasting
> a
> lot of electricity with them.  And waste generally means waste heat.
>
> Also, they can work *too* well.  The amount of heat transfer depends on
> how
> much current you give the device, but you can get one side *very* cold and
> the
> other side *very* hot.  The problem is that the cold side can form frost
> if
> you're not careful.  You definitely don't want that.  I've read that some
> people will make an airtight foam seal around whatever that put the cold
> side
> on, but that will depend on how your cooler is designed.
>
> And then once the heat is off the CPU and onto the other side of the
> cooler,
> you still need to get rid of it ASAP.  I think most people who have gone
> to
> the trouble of using peltiers use water cooling for this.
>
> As for your continuing heat issues, your probably on to something with
> regards
> to the reservoir size.  Have you tried putting a thermometer in the water
> to
> see how warm it is?  The more it rises above room temperature the less
> heat
> its going to remove from your CPU.  Alternatively, again depending on
> design,
> you might try a reservoir with more surface area or putting a heatsink on
> the
> reservoir itself.
>
>
> --
> --John Gruenenfelder    Research Assistant, UMass Amherst student
>                        Systems Manager, MKS Imaging Technology, LLC.
> Try Weasel Reader for PalmOS  --  http://gutenpalm.sf.net
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