low temperature coolants?

[coppercone2]

I am having viscosity problems with coolants. I tried IPA, a computer cooling fluid (coolance), and a mixture of 70:30 propylene glycol and water.


They all get rather viscous and do a number on my tubing.


What fluid can be used that stays the most liquid at low temperatures? I thought maybe methanol.

[jpanhalt]

I am having viscosity problems with coolants. I tried IPA, a computer cooling fluid (coolance), and a mixture of 70:30 propylene glycol and water.


They all get rather viscous and do a number on my tubing.


What fluid can be used that stays the most liquid at low temperatures? I thought maybe methanol.

Water can be used at freezing temperatures.  I have also seen liquid helium used for somewhat lower temperatures.

Edit:  Here's a small list from Burdick & Jackson:  http://macro.lsu.edu/HowTo/solvents/Freezing%20Point.htm

[geggi1]

Depending on what you are cooling you can maybe using a two phase cooling system like the one used in refrigerators.
There are several videos on Youtube showing how a two-phase cooling system is made with relatively simple but low quality components and butane gas.
If you use better quality components and do a bit of engineering you might be able to build a usable cooling system.

Another option is to use peltier elements for the cooling.
Heat pipes like the used om laptops might also be an option.

If you ar really determined to use a liquid based cooling system you will have to read up on the physical properties of liquids and find something that is better than what you have tried.
Ethanol alcohol might be a possible option if you use a high percentage because this is liquid until over 100 degree centigrade.

[coppercone2]

no I am looking for a non viscous when cold coolant for a coolant loop that uses a pump, its just a fluid loop. but all this shit gets syrup at low temps


non pressurized too, so you pour it into a tank and run through normal hoses

[Coordonnée_chromatique]

Shell Immersion Cooling Fluid S5X, the pour point is at -36°C

[coppercone2]

can this be obtained? I see something stupid like a 50 gallon drum for sale

[jpanhalt]

I thought it was obvious that critical information was not provided by the TS.

1) What temperature do you need?
2) How viscus can the fluid be?
3) Is flammability a concern?
4) What is the maximum price per gallon that you want to pay? 

(I am assuming non-corrosive and non-reactive are givens.)

[coppercone2]

I dunno im experimenting with cold its not a spec I just need stuff that is generally good.

the lowest temperature would be dry ice slurry.

Would not mind picking up a few different coolants so long its cheap. Its small stuff like 1/4 inch tubing

Since its stupid bullshit, I would say 200$ a gallon and I don't know anything about how to define viscosity. so it flows good in tubing, I don't actually know what the limits are. I just notice its kinking my silicone tubing when I use glycol stuff and it gets cold enough, its like pushing slurpee. I hooked it up with some stiffer tubing but that setup is not acceptable, I want it like test leads. I was hoping with maybe methanol I can use silicone tubing at lower temperatures. When it has the braided reinfroced tubing I am inclined to bury it in the yard because its just shit.

this one is with a gear pump

[mzzj]

96% ethanol is still pretty thin at -40c and freezes solid at -120c
At -85 ethanol is something like room temperature cooking oil or thinner.
Acetone has very low viscosity but freezes bit earlier than ethanol.

[mzzj]

Oh and if flammability is concern Halocarbon 0.8 is commonly used.
But it brings us to jpanhalt’s remark about maximum price you want to pay: at 3800 usd per gallonit is not for everyone!

[Doctorandus_P]

Liquid nitrogen has a pretty low viscosity.
Liquid helium is even much more betterer.

[coppercone2]

is ethanol a lot better then isopropyl alcohol?

maybe I should try it first before methanol,since its safer

[mzzj]

is ethanol a lot better then isopropyl alcohol?

maybe I should try it first before methanol,since its safer

about same according to this https://www.celsius-process.com/wp-content/uploads/2020/01/ethanol.pdf

methanol is 0,005 Pa.s vs IPA 0,011 Pa.s @-70
Toluene is about same or slightly better than methanol @-60

[Berni]

Butane has a boiling point of -1°C and has very low viscosity in liquid form.

In fact it is so low viscosity that some pumps have difficulty pumping it (It gets out of the way when you try pushing on it). But a positive displacement pump should have no issue. The other problem is that at room temperature butane is a rather flammable gas, however it only takes 2.5 bar to keep it liquid at room temperature, so it is a pretty sensible pressure that any tubing can hold.

If you want to enhance your cooling performance with phase change you can also go for Propane, it has a boiling point at -41°C so anything submerged in that stuff at atmospheric pressure will be kept rock solid at -41°C

[notsob]

try ethylene glycol 100% ( ie car antifreeze ) they used it for cooling in WW2 aircraft, should be cheap enough and readily available for you to test

[IanB]

All normal liquids are going to get a lot more viscous when cold than when at room temperature.

What temperature is dry ice slurry? A dry ice and acetone bath would be at -78°C. Everything safe and readily available is going to get a bit thicker and more syrupy at those temperatures. Ethanol is probably your best option to look at.

Also, 1/4 inch tubing seems a bit narrow. Things will flow a lot better with 3/8 or 1/2 inch tubing. Also, I guess you will need a peristaltic pump to do the circulation. Tubing that remains soft and pliable at -80°C is also going to be a challenge.

How cold do you really need or want to be, and why?

[T3sl4co1l]

Molten iron is a pretty good low-temperature coolant: it's highly abundant, has high heat capacity, low vapor pressure, and works down to the low temperature of 1900K making it suitable even on the smallest of brown dwarf stars.

Tim

[coppercone2]

try ethylene glycol 100% ( ie car antifreeze ) they used it for cooling in WW2 aircraft, should be cheap enough and readily available for you to test

i avoided that one for the same reason as methanol, i.e. when a hose disconnects and you get popped by a cobra

[IanB]

try ethylene glycol 100% ( ie car antifreeze ) they used it for cooling in WW2 aircraft, should be cheap enough and readily available for you to test

i avoided that one for the same reason as methanol, i.e. when a hose disconnects and you get popped by a cobra

Ethylene glycol is not good at all. Firstly it freezes at −12°C, and secondly it is quite thick and syrupy. It's the last thing you want.

[coppercone2]

anther problem with viscosity is flow meters. I doubt the acrylic flow meter I have is accurate with viscous cold liquids.

[jpanhalt]

anther problem with viscosity is flow meters. I doubt the acrylic flow meter I have is accurate with viscous cold liquids.

If you mean it's a floating ball flow meter like attached, then of course it is affected by viscosity.  One calibrated for argon will not be accurate for helium or water unless recalibrated. They also have a limited range of viscosities for which they can be calibrated.

There are other ways to measure such fluids, such as ultrasonic (2 types) and turbine wheel. 

[coppercone2]

yeah but since it changes with temperature so much I don't think you can ever calibrate it unless its for a specific operating point. it looks like the oval displacement ones are very expensive too.

[jpanhalt]

Of course you need to calibrate floating ball flow meters for specific conditions.  If what you have is from your welder, note it is calibrated for different gases or gas mixtures at a specific temperature.

That's why you want to use a different technology.  How about defining some of the variables.  From your previous posts, can we assume you want to use a peristaltic pump at -70°C?  Why not use a constant displacement pump?

[Berni]

As long as you have a positive displacement pump you can just measure the RPM of the pump and get your flowrate from there, it won't care about viscosity.

[Overspeed]

Hello

Be aware ethylene glycol is a toxic chemical even at low concentration that destroy the liver

As easy cheap fluid , Ethanol ( pure ) is ok , acetone is better but that not the friend of plastic / rubber ....
for ultra low temp ( minus 100 C ) isopentane can work

Regards
OS