The recent post regarding water cooling amps has been very interesting.
Since I would like to build a liquid cooled tube amp, I'm looking at
every bit of information I can find.
Some questions I have may possibly be answered by the collected
experience of the group so here goes:
Manfred raised a question about calculating the area required for the
liquid/cooler interface. Since I am trying to design an anode cooler, I
have the same problem. Has there been any answer that I missed?
When I was still working I had occasion to liquid cool a few silicon
based gadgets. From that experience I have a good feel for the plumbing
aspects of dealing with liquid (both water and oil) and electronics.
What I don't have is a good feeling about the problem of water and high
voltage.
It has been stated that distilled water and DI water are both chemically
active in the presence of metal. Is there an alternative? What about the
new lifetime anti-freeze? Anybody check it's electrical properties? What
about additives? I've seen mention of additives but no details.
What would be the best choice of metal for a cooler? (other than the
obvious thermal resistance issue). I've seen a lot of coolers made from
brass. Would not pure copper be less likely to contaminate the water
over time? How about the solder typically used? Would the lead free
plumbing solder be better than tin-lead? Maybe using J-B weld for the
cooler construction would eliminate some of the dissimilar metals. Heat
would certainly not be a problem since common vinyl tubing is usually
used and it melts long before J-B Weld would break down. Plastic
fittings? How about stainless steel fittings or for that matter how
about the whole cooler made from stainless assuming you could have
enough surface area to overcome the extra thermal resistance.
Assuming the cooler metallurgy is correct and you use common wally-world
DI or distilled water, will the water become contaminated just sitting
in the system over time? How long a time? I am assuming everything is
accelerated by heat and the current caused by the presence of high
voltage. Changing water is a issue for me. I don't want to turn on the
amp one day and find out I need to make an unscheduled run to
wally-world for some new water. Not to mention that draining the
"bucket" is a problem all in itself logistically speaking.
I am not particularly interested in complex and expensive solutions
employed in commercial applications like RF heating, SW BC and TV
transmitter and particle accelerators. Amateur radio based projects are
far more sensitive to cost and complexity and I seem to be more so in
that regard than most on this list. What I am interested in is cooling
solutions that I can build at home without government funding!
Thanks & 73,
Larry - W7IUV
DN07dg - central WA
http://w7iuv.com
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