What's the composition of the H100 coolant? Whats the freezing point?

[Shaocaholica]

I'm planning on running a series of winter tests in subzero ambient air in my unheated garage and patio. I'm posting to find out if the H100 is rated to run in subzero environments and if so, how low?

 

I know that pure water will definitely freeze but I've read that the H100 is supposed to have a mixture of water and ethylene glycol which should yield a freezing point below zero but the exactly value depends on the ratio of ethylene glycol to water. Is that figure published anywhere?

 

Also, will I have any issues with the pump and other components running subzero?

 

I don't know what the specific ambient temps will be but the lowest should be -10F to -20F. That's -20C to -30C.

[parsec]

I've never seen the ratio of water to ethylene glycol (EG) stated anywhere. Since the intent of adding the EG is to inhibit corrosion, etc, the amount added is much less than used in an automobile radiator, usually 40% to 50%. I doubt very highly the amount used in these coolers will prevent freezing of the fluid at sub-zero temps.

 

But who needs water cooling at those temps, you could probably use a good tower cooler with no fan, with a few case fans pulling air through the case.

 

That's an interesting situation, a PC in a very cold garage, I'd like to know how that works out. I bet you may have problems with the HDDs and even SSDs at sub-zero temps. CPU cooling will be the least of your problems, IMO.

[Shaocaholica]

The problem with heatpipe based tower coolers is that they will also stop working when its too cold to evaporate the working fluid. That's not to say it will overheat but it will be sub-optimal once you get too cold. You would almost want a traditional solid heatsink.

 

But still, I think the liquid route would be best if it did work sub zero.

 

As for other parts, I think I'll be fine with SSDs. I don't see how they would be affected any more than every other IC being used.

 

Bearing lubrication on the fans may be an issue but I'm willing to break a few fans if that's what it takes.

[parsec]

If the fluid in the H100 does freeze, it will expand and likely damage the pump or cause a leak when it thaws out.

 

At least one SSD I have has an operating temperature range down to zero degrees F, so who knows if that is really an issue. HDDs at -20F is something I would not try.

 

Fans could be an issue at that temperature. I wouldn't worry about heat pipes not functioning at that temperature, just remove one side of the case, and I bet it would be fine. Electrolytic capacitors, although much less common in PC components lately, might be affected at -20F.

 

I might just try that with an expendable PC (?) this winter. I wonder if temperature monitoring software will display correct temps?

[peanutz94]

I remember an earlier thread and i believe RG stated it was a 50/50 mix.

 

As far as testing in cold weather goes, I'm going to bet you dont have any issues. I cant see fans or or heatsinks (water or air) being afffected buy just cold. Look at the heavy OC'ers that use liquid nitrogen for cooling and those systems work great. All beit they are not using a water type cooler, they system still works at well below sub zero temps.

 

I used to work in the local steel mills and they have tons of computers that sit out in cold weather all the time and they work just as good as they do when it's warm. And that is with just fans for cooling.

[Shaocaholica]

I remember an earlier thread and i believe RG stated it was a 50/50 mix.

 

That ratio should allow for operation at -20C -30F but just barely. Anyway, those temps are just worst(best?) case scenarios. Not to say that it really is 50/50 but it would be nice if it was.