Cooling fluids and near replacements...

[Externet]

Hi fellows.

What are the parameters of consideration to evaluate the suitability of a fluid used as a closed circuit circulating and pumped cooling media ?

Thermal conductivity, specific heat, thermal transfer index, heat capacity, viscosity... what else?

 

The circuit to be a machine that gets hot and a heat exchanger to cool the circulating fluid.

 

To replace a coolant such as transformer oil with plain water, or diesel, or transmission fluid, or other suitable ones.

Or reverse, as replacing plain water coolant with kerosene, or very thin oils with viscosity near water.

[John Cuthber]

Flammability, toxicity, corrosivity and, in at least some cases, electrical conductivity.

[Enthalpy]

Keep a stable and uniform composition at prolonged heat, not degas...

Be a good lubricant so the pump lives long, and that's difficult. It needs a good viscosity at high shear numbers, among others.

Wet solids easily. De-foam quickly.

Allow long storage, preferably at air and at cold as well.

 

Flammability isn't easy to check. High pressure leaks can build a mist. Heat makes it worse.

 

If you consider glycol, please prefer propane diol or polyethylene glycol. Simple glycol is a poison that tastes sweet.

 

Put together, using a known hydraulic fluid like Hydrolub as a cooling fluid looks easier and safer (but this one doesn't insulate).

 

Do NOT replace transformer oil by anything else in electrical uses: it's highly optimized as an insulator. Any other liquid will fail, possibly after months of operation, with BIG consequences.

 

If water was needed for its performance, replacement is nearly impossible. Put additives, at most.

Edited September 4, 2012 by Enthalpy

[InigoMontoya]

Don't forget cost and availability.

[Externet]

Thanks, gentlemen.

[chilehed]

Compatibility with all of the other materials in the system.