Interesting idea, Bill. I wonder if folks on the reflector have tried
vapor phase cooling? In principle, that should be the most effective
cooling scheme of all, given the high latent heat of vaporization of
water. Of course, the devil is in the details, and the practicalities
might be too burdensome. This is an interesting discussion.
Jim w8zr
Sent from my iPhone
On Jun 6, 2013, at 9:05 AM, "Fuqua, Bill L" <wlfuqu00@uky.edu> wrote:
> You have given me an idea.
> May not be original but here it is.
> One problem with the heat transfer from the newer high power devices is
> making
> a good reliable contact with the heat sink. You could use liquid cooling.
> The thought is to mount the device on a flat hollow channel carrying water
> with a rectangular hole and
> seal or gasket such that the water comes into direct contact with the devices
> heat
> dissipator. With adequate liquid fluid flow the device dissipate its heat
> directly to the
> fluid, perhaps water, much better than you would have with a metal to metal
> to air
> heat transfer scheme. Warping of the metal is not such a problem either.
> 73
> Bill wa4lav
>
>
> ________________________________________
> From: Amps [amps-bounces@contesting.com] on behalf of David Lisney
> [g0fvt@hotmail.com]
> Sent: Thursday, June 06, 2013 10:35 AM
> To: amps@contesting.com
> Subject: Re: [Amps] Solid state amplifier cooling
>
> I used to be in the PC overclocking scene many years ago, I used peltier
> heatpumps and a homebrew water cooling system to keep the CPUs cool, and it
> did let them operate at extremely high clock speeds... However, the CPUs
> rated power interpolated to about 40w a piece and the peltier devices were
> using over 70w a piece. There are published curves of heatpumping capability
> versus temperature differential etc, mine was quite a high differential
> trying to run CPUs at close to freezing with a water cooling circuit at
> probably 30c.
>
> I found the biggest challenge was dealing with condensation, ambient air
> needs to be excluded from areas that are operating below the dew point. The
> second issue is algae growth!
>
> One thing I did learn and will use again is the enormous heat capacity of
> water, on doing the maths it was surprising just how small a pump is required
> and just how little flow is required.
>
> At the KW level I am sure a vehicle radiator with a very low power fan would
> suffice, in the case of my computer experiment I only had a few hundred watts
> to shed and a vehicle heater matrix easily coped (blown by a pair of 120mm
> 12v fans operated at 7v).
>
> I think I would still use a computer fan in the vicinity of the PA section,
> obviously it is not just the output transistors that generate heat.
>
> Watercooling also enables the fans to be remote and keeps the noise away from
> the operator.
> Mind you a transistor PA with no tuning is easily remote controlled....
>
> Just some thoughts, I have not posted for years but I do read this thread
> every day.
>
> 73 de David G0FVT
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