[Amps] Water cooled amp question

[Japerlick@aol.com]

Sure, you could use Glycol, but why would you want to?

Glycol has very high "Enthalpy" which means it can hold a lot of heat per 
unit volume.  It is also really poinsonious.  There are LOTS of other good fluids 
one could use, but why?  Water is great!  

Cray Research used Flourinert, made by 3M, in their computers.  The entire 
computer, circuit boards and all, were inside a flourinert solution which was 
continously circulated to draw heat out of the ECL logic.

I recommend normal distilled water.  I would not use de-ionized (DI) 
water..it is very corrosive.  It's often used as a final solvent in cleaning PCB 
boards...because it quickly dissolves salts and other residues found in filtered 
water.  It's really pretty nasty stuff.  Distilled water is probably 
great...just change it out once a year or so, just to keep any particles that might fall 
off into the water out of the4 system.

The question of how much heat you need to cool is a thermodynamic 
calculation.  Look at it like an air conditioner.  You need to cool the water by a 
certain number of degrees (in C or F or K or whatever).  You have a heat exchanger 
that will HEAT the water (the tube) and one that will cool the water (the 
chiller).  You can work in Watts, but thermodynamicists usually work in BTU.  I 
would think a cooling coil in the range of a large heat  coil from that  1968 
Caddilac would be about right.  An auto radiator is probably far too big.  And, 
remember, you will get a temp "difference" when you run through the radiator.  
If your radiator is already very hot (sitting in the Arizona sun), you may not 
be cooling that water too much!

Another factor is the flow rate.  You want to run it slow and fast for 
different reasons.  Fast will pull heat out of the tube quicker, up to some point.  
But, it will also decay the system quicker too.  Water itself is a pretty 
"Hard" substance and all that water rushing by at really high speeds will act like 
a little sandblaster and slowly chip away metal.  In fact, some metal cutters 
use super high speed water jets! Water can be an amazing cutting wheel!

Plastic tubes sound a little scary.  100C is not hot at all....I would 
imagine that the tube and/or water can easily exceed 100C.  I would get tubing that 
can handle temps well above boiling temp (212F, 100C).  In fact, I would think 
stainless steel tubing or copper tubing would be the best solution.  You can 
always put a short insulator in line somehwere near the tube.....unless it has 
a ceramic pad or something.  

Good luck...sounds like a kind of hairy project!  

And, never use an "Open" system.  Make sure your water system is sealed so 
nothing can contaminate that distilled water!

> 
>   Stan, I might suggest that you look around for one of those (used) 
> little "window box" type of swamp coolers...  then you can use the 
> hi-volume pump to not only pump water through your heat-exchanger (car 
> heater core, or similar) but you can divert a bit of the water to use in 
> the cooler, or run deion water in the 'tube circuit' and place the 
> heat-exchanger in the air-stream of the little cooler.  I've done this for 
> cooling hydraulic systems and process water, and big 35MM movie projector 
> water-cooled gates.
> 
>  Also, if you plumb with the 'food grade' clear plastic tubing, it will 
> eliminate the conductivity problems. And most of that will hadle 100C and 
> above...
> 
> 
> 
>   Question for The List: Could not one use glycol? (Antifreeze) in the 
> tube circuit?
> 
> 
> Cheers
> 
> John  KB6SCO
>