Date: Mon, 06 Mar 2017 14:04:26 +0000
From: Manfred Mornhinweg <manfred@ludens.cl>
To: amps@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
water.
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.
Manfred
## 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
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|