[Amps] SS amps watercooling - was PowerGenius XL

[Roger (K8RI)]

1st, they don't use water. As I said in the post, Water, Vapor phase 
cooling is too hot for SS amps/circuits.  100C will work, but the life 
of the device would be drastically shortened.  Vapor phase cooling CPUs 
is done with a liquid that vaporized at a much lower temperature than water.

In modern RF power transistors, there is very little minority carrier 
migration, but much above 70C this happens more readily.

I don't know the calories per minute limit for the closed circuit, CPU 
cooling, but using chilled water on a 12 KW, out RF generator (class C) 
only required a gentle flow out of a quarter inch hole. (3/8ths and 1/2" 
hose to the clear plastic monitor))

Computers used by diehard gamers who push the CPU's limits, by over 
clocking ( seeds over the published ratings) and heavy use of the CPU, 
regularly use "Open circuit" , or closed circuit chilled water for 
cooling rather than the radiator mounted on the computer case using two, 
or 4 fans. OTOH the commercial, closed circuit cooling with the radiator 
on the tower are a somewhat easy/shortcut to handle the heat from some 
standard, 8 core CPUs running at 4.7 GHz and faster.  Some come with a 
single core closed circuit cooler

 From experience, I doubt any of these would be adequate to cool the 
dissipation of a legal limit amp on digital. Many  full size computer 
tower cases come already equipped/designed for the use on an external 
source and discharge of coolant.

It's not uncommon to see water cooling used on both the CPU and vireo 
card, but for serious heat, they, like water cooled ham amps, resort to 
an externally supplied coolant.

I would not expect any of these multiple fan CPU coolers to 
satisfactorily cool a legal limit SS amp.
The multi fan units are quiet, but they can have the fans configured in 
a push pull arrangement for "some" increase in capacity and noise.

Using the double size radiator requires careful selection of the tower 
and often, like home brew amps may require some metal work.

Sounds like a good experiment for someone to find out just how much heat 
one of these could handle, or how the cooling circuit would need to be 
modified.

73,  Roger (K8RI).

On 2/17/2017 4:14 PM, Jim Thomson wrote:
> Date: Fri, 17 Feb 2017 12:53:53 -0500
> From: "Roger (K8RI)" <k8ri at rogerhalstead.com>
> To: amps at contesting.com
> Subject: Re: [Amps] SS amps watercooling - was PowerGenius XL
>
> Water is far easier to clean up, leaves less mess, and is more efficient
> at heat transfer.  The vapor phase cooling used in computer CPU cooling
> is efficient, but less tolerant of leaks, difficult to charge, and works
> at lower temps..
>
> Vapor phase water cooling is very efficient (already covered by another
> poster) for tubes as vaporizing 1 gram (1 cc) of water uses 539 calories
> (at 100 C - too hot for SS), while heating or cooling water 1 deg C
> takes 1 calorie.
> Vapor phase cooling has no moving parts except for a fan(s) at the radiator.
>
> 73, Roger (K8RI)
>
> ##  How the heck do they do vapor phase cooling with a cpu ?   Vapor phase
> cooling works on the premise that the water is brought up to a boil.  And thats
> with normal sea level pressure.   Put the system loop under pressure, and the
> boiling point  will rise by a bunch.  Will a cpu handle 212 F ?
>
> ## I  dont think these  LDMOS devices will  handle  212 F temps ??   If they
> do, then vapor phase cooling would be ideal, and the pump can be eliminated,
> and the external rad + fan could be made very small.....  like the alpha vapor phase
> cooled amp.
>
> Jim  VE7RF
>
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