[Amps] water or vapour phased cooling for SS

[Jim Thomson]

Get out your old dog eared copies of care an feeding.    The online version has dumped
the parts  about  Nukiyamas  theory of boiling water.   You will notice they depict the chart
and graphs  for steam from 100-1000 deg C.      Peak eff  for vapour phase cooling is at 130 deg C
and not 100 deg C. 

If you read  carefully,  vapour phase cooling is not all its cracked up to be.  Read the fine print
in the eimac book.   Forced air cooling is capable of  50 watts per sq CM of internal anode area
of a tube.   Vapour phase is good for just 135 watts  per sq CM.     And water is good  for  1000 watts
per sq CM.    Water is still  way more capable of removing loads of heat  vs vapour phase.  And the
colder it is, the better it gets.  Crank up the flow rate, and it gets even better. 

Why  do the transistors have to have an insulator between em and the heat sink anyway.  Why
not just mount them directly to the heatsink.    Then use stand offs  to  float the  heat sink
above any chassis.    I used to do that with zener diodes in GG amps, worked good.   That’s
cuz I was living out in the bush  back in the 80s..and had no proper insulator at the time. 

The ultimate heatsink for  SS would be a solid block of copper, with  water flowing through inside it,
and stand offs to float it.  Then use an external  HE- radiator, high flow rate, and a  huge reservoir
in series with the flow lines...and loads of air on the  HE.   The .5 -2 gallon reservoir acts like a giant capacitor.
Cooled water from the HE  goes to the reservoir.... then to pump...then to the heatsink.  
>From heatsink back to  the input of  the air cooled  HE.     An even better medium would be to use FREON.

Big diam myriad of  a labyrinth of holes in the copper heat sink... then the in-out freon lines are reduced to
a small diam  back to the compressor  + external  HE.....just like a freezer.   freon is liquid when inside a 
small diam tubing.   where it morphs into a large diam tubing, it turns to gas.... and gets really cold.

Seems to me that water boils at 167 deg F  at the top of mt everest..making  for lousy coffee-tea. 
that’s due to low pressure.    Dunno if vapour phase cooling would work at 167 degF   in a partial
vac environment or not.  

Another scheme would be  multi-phase  cooling..like used in some eimac tubes.   goes in as water,
morphs into steam.... then back into water..all inside the same tube.   The water goes in at high pressure
the steam formed does not get the surface bubbles.  Well it does, but the velocity is so high, it strips the
bubbles off as fast as they form.  it’s a slick  cooling system.   You get the best of both  water and vapour
phase cooling. 

Another method would be to just use water cooling..but use a massive reservoir as the heatsink..like a 
10-55 gallon  drum just outside the home.   Then its just a big loop..and no water wasted. 
Plan B would be to just use cold tap water like used  for 50 ohm dummy loads.  Attach the garden hose,
and turn it on... then  dump the warm water  onto the lawn some where.     those  bird and cd  water
cooled dummy loads use a garden hose fitting.  they will  dissipate one helluva lot of CCS heat..and fast.
For a  1.5 kw  SSB-CW  or even  RTTY ,  SS amp, you would not need any where near as much flow rate. 
once cool, like for  extended RX, flow rate is zero. 

Ok roger... pick on and build it for us.   

later.... Jim   VE7RF