[Amps] oil vs distilled water cooling.

[KA4INM]

   On 04/16/2015 03:09 PM, Steve Wright wrote:

   /* snip */
>> All of the amplifiers I design and use at work are water cooled, some
>> flowing water and some multiphase, or hypervapotron mode, which is the
>> same thing but a trademark. Its not a tough problem to crack, and I'm
>> dealing with considerable HV. I studied the RCA, Eimac and Thomson
>> recommendations some years ago, and use a common set of specifications.
>> Keep the DC leakage current in the hoses < 500 uA per hose. So for
>> whatever resistivity is maintained, the hose diameter and length is
>> designed for this current (resistance) at the maximum plate voltage to
>> be used. DI water is closed loop cooled, as its New Mexico and we cannot
>> waste water. This complicates things with heat exchangers and secondary
>> loops with cooling towers. Since the water is recycled, we have to watch
>> the ph and the dissolved oxygen level as well. For < 5 kV DC I think the
>> requirements are much less difficult to meet.

> Um. Why. Not. Just. Use. Oil.  And be done with all those problems ??

> Because the oil is flammable?  Is that the only reason?  How many of
> your water cooled amps leak AT ALL?  If they didn't leak water, why
> might they leak oil?

> I don't get it.

   Water requires more energy per gram of liquid to change its
temperature.  Water can hold more heat energy than oil.

Thermal Conductivity
Liquids
Mercury			8.3
Water			0.67
Methanol		0.25
Glycol, Antifreeze	0.25
Ethanol			0.14
Liquid Nitrogen		0.14


  Specific Heat Capacity
Specific Heat Capacity is the amount of heat a particular
substance can hold.
  Liquids
Water			4.18
Methanol		2.55
Ethanol			2.48
Glycol, Antifreeze	2.38
Liquid Nitrogen		2.04
Benzene			1.72
3M Flourinert FC-43	1.10
Freon 11		0.87
Mercury			0.14

   Everything has been tried and usually
water functions better, is cheaper and is
infinitely recyclable.
   (it can be consumed with no harm)

   When you add enough antifreeze to a car's cooling system
to prevent freezing to -10 degrees F you have reduced the
cooling capacity to about half of what it was with just water.

   I have known of a hose popping off of a barbed fitting
even being double clamped, not to me, and 135 gallons of
distilled water sprayed around the room and all of the
equipment got a dose before the sump was pumped dry.
   It was cleaned up in 10 minutes with a mop and bucket
and the air conditioners.

   see:  http://koolance.com/cooling101-heat-transfer
-- 
   Ron  KA4INM - Youvan's corollary:
                 Every action results in unwanted side effects.