[bknight]

http://www.evanscooling.com/catalog/C_npg1.htm
we run this stuff in are atvs to help on corrosion and to run cooler.
do you think it would work in water cooling pc.

[Bugsmasher]

Since it appears that thier products are 100% or near propylene glycol that product is basically 100% antifreeze with some small amount of additives if I understand correctly.

Now while this would work well for traditional hot running motors in the watercooling environment I would think you would be taking a rather large performance hit due to the small range of temperature changes in the coolant fluid. I remember reading somewhere that the temp changes in the fluid as it travels through the CPU block were in the vicinity of 1/10th of a degree celsius.

Thermal capacity and transmittance is the name of the game when it comes to watercooling computers and water to date is still just about the best to use.

[Revivalist]

Originally Posted by Bugsmasher

I would think you would be taking a rather large performance hit due to the small range of temperature changes in the coolant fluid. . . .
Thermal capacity and transmittance is the name of the game when it comes to watercooling computers and water to date is still just about the best to use.

I'm a little confused. I thought the ideal fluid should be able to absorb a lot of heat without changing in temperature much. (In other words, it should have a high "specific heat" as it's called in physics.) That's why I thought pure water is ideal because it has a high specific heat but it needs to be mixed with additives to avoid algae, etc.

[batboy]

Pure water (i.e. distilled water) is probably the best for transferring heat. Trouble is, it will also corrode and algae can possibly grow. Combine this with the fact if your heat fails in your house/apartment this winter while you are gone, then it will freeze. I'm not going to recommend additives since I'm a noob at this too, but generally adding a little bit of antifreeze that has a corrision inhibitor is a good thing. There are a bunch of threads on this topic. I encourage you to search and read like I've been doing lately. I'm overhauling my watercooled system and gearing up to do this soon too.

[Bugsmasher]

Originally Posted by Revivalist

I'm a little confused. I thought the ideal fluid should be able to absorb a lot of heat without changing in temperature much. (In other words, it should have a high "specific heat" as it's called in physics.) That's why I thought pure water is ideal because it has a high specific heat but it needs to be mixed with additives to avoid algae, etc.

The thermal conductivity of a 50% propylene glycol coolant is around 0.361 W/mK (Watts per mili-Kelvin) while that of water is near 0.606 W/mK (higher is better) at approximately room temperature. The ability of a fluid to 'conduct' heat changes as the fluids temperature changes. For the products you linked their sweet spot is right at the boiling point of water (100C)where their thermal conductivity peaks at a round 0.401 W/mK. In computer water cooling however you are normally talking about temperatures in the 23-30 C range for which water is much better suited. Antifreeze in computer watercooling is normally used as an anti-corrosive while in vehicle engines its used to lower the freezing point, increase the boiling point, as well as for its anti-corrosive properties. The ability of that propylene glycol mixture (near 100%) to remove heat from the CPU block would be nearly 1/3 less effective than a near pure water coolant solution. 100% Propylene glycol would have a negative impact on cooling performance, slightly higher anti-corrosive capability, and its ability to raise the boiling point and lower the freezing point would not come into play.....UNLESS you were going for some form of extreme cooling attempting to lower your coolants temps to sub zero celcius (freezing point of water).

Keep in mind the above numbers are for a 50% propylene glycol/50% water mixture. As you increase the percentage of propylene glycol increases the thermal conductivity of the solution will decrease.

While the thermal capacity may be higher for propylene glycol the thermal conductivity is lower.


Short less wordy format-

Molten Iron has a higher heat capacity than water as well but in the environments normally seen in watercooling....

(not being tacky, just an extreme illustration of the concept)