[Amps] SS amps watercooling - was PowerGenius XL

Jim Thomson jim.thom at telus.net
Mon Mar 6 11:32:37 EST 2017

Date: Mon, 06 Mar 2017 14:04:26 +0000
From: Manfred Mornhinweg <manfred at ludens.cl>
To: amps at contesting.com
Subject: Re: [Amps] SS amps watercooling - was PowerGenius XL

Okay, folks, can we then perhaps reach some consensus, or recommendation 
about what exact liquid to use in watercooled electronics?

It has to be water-based, because there is simply no other liquid that 
matches water in terms of specific heat, availability and cost.

We don't want buildup of anything in out heat exchangers. So we must 
make sure that the liquid is pretty much free from calcium, magnesium, 
carbonate, silicate, sulfate and other such ions that tend to 
precipitate on hot metal surfaces and form scales. This rules out tap 
water (unless it's very soft).

We don't want algae growing either. This pretty much requires some sort 
of alguicide added to the liquid. Otherwise we WILL get them, in the 
long run. What to use? Chlorine ions? Hypochlorite? Some alcohol?

We don't want corrosion. But a tiny amount of corrosion should be no 
problem. If we load the amplifier with distilled water, and that water 
rips some copper from our tubing and heat exchangers, until reaching a 
balance, is that so bad? I think we can live with it. If not, then we 
would need some sort of corrosion inhibitor if we start from distilled 

Conductivity may or may not be an issue. With a typical LDMOSFET amp, 
that has the source (and cooling block) at ground potential, and every 
other metal part of the cooling system at ground potential too, 
conductivity is a non-issue, as long as there are no metals with very 
different electrochemical potential there (because then one of them 
would corrode the other, by electrochemical action). It should be easy 
enough to make the whole system just from copper and plastic, so that 
there would be only one metal, and no electrolytic corrosion. Then we 
simply don't need to worry about conductivity.


##  IF conductivity is NOT an issue, then Id suggest using what is already 
being used in car eng radiator setups.  Distilled water + a corrosion inhibitor. 
Typ a 50-50 mix of glycol + distilled water is used.  The glycol offers the 
inhibitor properties, and also raises the boiling point by a bunch, to typ 265 deg F,
IF under  typ pressure of 10-15 psi.  Less, with lower pressure, but still  more than
212 deg F.  That 50-50 mix  will also lower the freezing point to aprx  -40 deg F.
You can also buy the 50-50 premixed, just pour it in.  

##  But for absolute max heat transfer,  100 % distilled water  from your grocery store,
+ redline water wetter is the bomb.  The water wetter has the anti corrosion  + anti 
electrolysis inhibitors in  the formulation..and anti everything else.   It also stops bubbles
from forming, when the water does get to the boiling point.   100% distilled water + water
wetter is used all the time, in spring, summer, fall  months, for the hot rod folks.  Its ALL that is allowed on 
most race tracks, including oval, road course and also drag strip.   On our local track, unless the car is
under warranty, they  will not allow the use of glycol. 

##  100% distilled water +  redline water wetter  will not put a dent or corrode or damage
pumps, aluminum eng rads, brass fittings,  AN fittings, SS, etc and  also supercharger intercoolers
and  heat exchangers.   Folks have been running the distilled water + water wetter for years on end,
with  zero failures.   80 %  distilled water  +  20%  glycol will  also work good.   Its not like you 
have to worry about freezing temps in your home.   How often do you flush the rad in your car. 

Jim   VE7RF  

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