bmcculla said:
Distilled water is also nonconductive.
I refute this statement - pure water, distilled water, whatever you call it, whilst in liquid form, will conduct electricity. True, it is less conductive than impure water, but nevertheless is still conductive.
The molecules of pure liquid water, at room temperature (25 degrees) and pressure (101.3 kPa) will split into hydrogen ions and hydroxide ions, at a concentration of 10^-7 mol/L (which is what is meant by "pH 7"). The presence of these ions causes conductivity. You could stop the creation of ions by freezing the water, but then it would be no good as a coolant :roll:
(For the non-chemical engineers around here, "pH" is a measurement of the concentration of hydrogen ions in a substance, whereby the pH is the negative of the log of the concentration of hydrogen ions. eg, a given a hydrogen ion concentration of 10^-4 mol/L, the log of that is -4, and the negative of -4 is 4, so the pH = 4)
As I understand it, the most commonly used direct coolants for computers (as used in supercomputing for many years) come from a family of chemicals known as perfluorocarbons, aka PFC's. These are carbon chain molecules, whereby the hydrogen side groups have been replaced with fluorine atoms. In particular, perfluoropentane (C
5F
12) and perfluorohexane (C
6F
14) are used in sealed systems, for cooling of electronics.