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[O/C]Coolant/Fluid Roundup - Thermal Performance

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Nov 1, 1998
A topic that seems to resurface every couple of weeks around the forums is what coolant/fluid is best; this usually ends up turning into a heated debate of opinions with no data to douse the flames. There is an ever-growing variety of coolants that are available in a rainbow of colors, which is great for those of you trying to achieve a certain color scheme where colored tubing just will not cut it or you have nightmares when your reservoir contains a clear fluid that just does not match your color scheme.

SL-Coolant_prodshot.jpg

A variety of fluids on the market have been marketed as anti-corrosive, non-conductive,... ... Return to article to continue reading.
 
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Very nice article!

I'll be using distilled water with biocide from now on.
 
Yea, Skinnee is the authority on good cooling testing these days, and I'm glad to see some solid numbers on this... I wouldn't have guessed the variation between fluids would be so small.

I'm still having a hard time believing Fluid XP is that much different, but I can't see how the results could be wrong given the methodology. Its just so much worse compared to the others, its hard for me to comprehend how you could make a coolant/fluid that much different in light of how consistent all the other products are with eachother.
 
Interesting, all the GPU stuff is within ca. 2 standard deviations (with the exception of Fluid XP), suggests that there really isn't much difference between any of these solutions....

Do you have any idea what your error is? How accurate is your thermocouple?
 
Interesting, all the GPU stuff is within ca. 2 standard deviations (with the exception of Fluid XP), suggests that there really isn't much difference between any of these solutions....

Do you have any idea what your error is? How accurate is your thermocouple?

I think vapor said .125C...but I could be wrong...i'll let skinnee give you a definitive answer

EDIT: well that was quick, found vapor's post (forgot he wasn't under vapor) http://overclockers.com/forums/showpost.php?p=6618292&postcount=18
 
Fluid XP nanofluid (ion scavenging nanofluid, ie not an attempt at thermal enhancement) is the only one that is at least 50% ? propylene glycol, based on their web page description of designed for fuel cells and chemical properties description including specific heat capacity, boiling, freezing, etc, ie it is likely this stuff.

All the other liquids from their description I believe are 85% water or higher, probably main reason why Fluid XP nanofluid is not with rest of the pack. Guess you pay a big thermal performance price for the extra weeks of slowing electrical conductivity.
 
Scratching head....

I'm not sure why this is really a big surprise...

Water has one of the best thermal capacity vs. thermal resistance of any "cheap" liquid. There are only 3 reasons you really even add anti-freeze to your radiator in the first place: boil over, freezing, and anti-corrosion/pump lube. If you lived in a place where it was always 50F you could probably run straight water and a little water wetter.

Now much like the liquid nitrogen guys I'm sure 3M or someone has a hydrocarbon based liquid that has some better properties. And I'm sure it's probably in that magical range of $1k per liter or something. That and it'll probably only get you %10 better theoretical specs...

I guess I've just been out of water cooling to long. I didn't even know companies made things like this. I thought most of the time it was just water or water/water wetter (or your additive of choice).
 
Excellent

This is computer journalism at its best: evaluating whether there's any appreciable differences between these (often expensive products) and just simple distilled water + biocide. This is the type of reporting that causes us all to step back and re-evaluate our buying decisions, and it provides a great deal of value to the community.

I can't stress enough how important I feel it is to take a critical look at our own practices, to see what is worthwhile and what is not. And this is exactly what you have done.

Bravo! More of this!
 
i would really like to see some tests under the same conditions using distilled water and water wetter... the stuff used in car radiators that reduces surface tension... i always use the stuff in my motorcycles and it definitely drops temps quite a bit... but we are dealing with much higher energy transfers / flow rates and temps... so it might not have nearly as much of an effect on something like a comp.
 
The temp of engine parts can get above 100C causing the water or water/glycol (even higher temps) to form localized vapor bubbles ie steam, and steam has a thermal conductance of 0.016 W/M*K or roughly 38x worse than water (0.6 W/M*K). Water wetter works by reducing surface tension, reducing vapor bubbles. Water wetter since coats metal may worsen cooling in parts of engine that dont reach 100C, though may improve temps in parts of engines that are running very hot, ie may be more effective in racing.

But without temps reaching 100C and steam forming, water wetter will simply result in worse temps, so for computers it is not going to help. There is some argument on how much worse temps are with water wetter, so would be interesting to see if it really coats the metal to the point of really worsening temps, or just dilutes the water with reduced thermal performance liquid causing a slight worsening of temps.
 
Judging by everything in the review, I think its safe to say water wetter is worse but not enough worse to be worth wasting time discussing unless you have high quality testing equipment capable of collecting highly accurate data.
 
i would really like to see some tests under the same conditions using distilled water and water wetter... the stuff used in car radiators that reduces surface tension... i always use the stuff in my motorcycles and it definitely drops temps quite a bit... but we are dealing with much higher energy transfers / flow rates and temps... so it might not have nearly as much of an effect on something like a comp.


What kind of motorcycle are you talking about? We are currently talking to KTM about testing our stuff in their motorcross bikes. My partner used to race for Husky, so we might put it in one of his old bikes. I have R6 and have been debating putting it in it, but I live where it gets below freezing and we haven't done any glycol tests yet, but that is being done elsewhere for us. What we hope to do is drop the weight of the cooling system and help with the endurance races - where the motocross bikes get really hot. We are also puting it in a short track race car to help with its temps.
 
a pressurized system boils at a higher temp. in an unpressurized system your water will stay at 100C until all the water is turned to steam. After it is all steam it is superheated and the temps can rise extremely fast. Your radiator would try to change it back to all liquid, so it would have to get rid of a lot more energy. But, a radiator is meant to only get rid of so much heat (X amount of Watts), so if your engine is producing more heat than your radiator can handle you'll end up with a runaway system and blow your head gasket..:)
 
I've also been meaning to question the conventional wisdom of adding water wetter, aside from anti-corrosion, anti-fungal, or other secondary properties.

As far as a surfactant goes, if there's no air-water interface (i.e., a surface), there's no surface tension to worry about. As far as I understand it (and I don't watercool myself), there's no air in these systems. So aside from unlikely scenarios of localised vaporisation mentioned above (giving a water-vapour interface), I see no point in it.

In fact, in the case where there are no air-water or water-vapour interfaces, a surfactant should accumulate along the edges of the tubing and other components. This is generally the lowest-energy distribution in a water-surfactant mixture. So, unless its thermal conductivity is better than water, it's an insulator. (I'd imagine it could act as a lubricant if its viscosity were right.)

Could somebody explain why this has come to be used in watercooling setups in non-extreme temperature ranges?
 
ok, more noobieness on auto comin, and I'm takin this from a watercooling side, but wouldn't the water in the system stay about the same temp, meaning all the water would have to reach 100c before any of it boiled, and if it did begin to boil, the enormous amount of energy needed for that phase change would boost the temps in the rad...iator (can I abbreviate it here...i'm not sure, back to the point) increasing the effectiveness of the cooling and causing it to reach equilibrium well before any water could boil? Or is there just some ungodly enormous amount of heat being generated by these things that a rather small radiator is having to dissipate (sorry to come across so newbie...I can only sorta fix cars, so performance mods are out of the question :D)

metal around cylinder heads reach 150C which causes localized vapor bubbles to form, it would be like taking a blow torch to a swimming pool, under the blow torch steam would form but few feet away in the pool the water temp could still be room temperature. Water wetter simply decreases the formation/size of bubbles in localized hot spots.

@macklin01, yeah I dont get how water wetter got started with computers either, makes no sense at all, I guess someone just made a lot of assumptions based on water wetters marketing without bothering to look up how it works. A few people on XT have used it long ago when mixing metals was more common and always complained it coated metal, was difficult to clean off, and did just what you said, it acts like an insulator and significantly increased temps...but havent ever tried it myself.
 
metal around cylinder heads reach 150C which causes localized vapor bubbles to form, it would be like taking a blow torch to a swimming pool, under the blow torch steam would form but few feet away in the pool the water temp could still be room temperature. Water wetter simply decreases the formation/size of bubbles in localized hot spots.

@macklin01, yeah I dont get how water wetter got started with computers either, makes no sense at all, I guess someone just made a lot of assumptions based on water wetters marketing without bothering to look up how it works. A few people on XT have used it long ago when mixing metals was more common and always complained it coated metal, was difficult to clean off, and did just what you said, it acts like an insulator and significantly increased temps...but havent ever tried it myself.

From what I gather, it goes back to the early days before me by at least 3-5 years. It was wild west back then, you use what seems best and go for it. When I first started over 2 years ago, there still was discussion on what antifreeze was best. Blue or red. Meaning VW or Toyota.

WW was made for racing, to give some benefits to racing rigs without having to use antifreeze, which reduced cooling, but still had some of the properties needed for a cooling system.

Thats what I gather from reading, and the internet in it's wisdom has old posts that will forever continue the myth.

So, it's not needed these days.
 
Thanks, guys. Glad to see I'm not just missing something obvious.

@RGE: The physics you describe sound exactly right to me.
 
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Thanks, guys. Glad to see I'm not just missing something obvious.

@rge: The physics you describe sound exactly right to me. Somewhat off-topic, you'd probably really enjoy hydrodynamic cavitation.

You should move such talk to more adult forums. I' won't report you this time.


Hydro cav.... lalalalala! I don't hear that! lalalalla!

LOL, sorry.......... lalalala!
 
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