low temperature coolants? - Page 1
Forum section: electronics / general

author: coppercone2
author_rank: Super Contributor
timestamp: May 05, 2024, 05:02:13 am
content: 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.

author: jpanhalt
author_rank: Super Contributor
timestamp: May 05, 2024, 09:14:05 am
content: Quote from: coppercone2 on May 05, 2024, 05:02:13 amWater 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

author: geggi1
author_rank: Frequent Contributor
timestamp: May 05, 2024, 09:25:24 am
content: 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.

author: coppercone2
author_rank: Super Contributor
timestamp: May 05, 2024, 09:30:00 am
content: 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 tempsnon pressurized too, so you pour it into a tank and run through normal hoses

author: Coordonnée_chromatique
author_rank: Frequent Contributor
timestamp: May 05, 2024, 09:40:34 am
content: Shell Immersion Cooling Fluid S5X, the pour point is at -36°C

author: coppercone2
author_rank: Super Contributor
timestamp: May 05, 2024, 09:45:53 am
content: can this be obtained? I see something stupid like a 50 gallon drum for sale

author: jpanhalt
author_rank: Super Contributor
timestamp: May 05, 2024, 09:58:04 am
content: 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.)

author: coppercone2
author_rank: Super Contributor
timestamp: May 05, 2024, 10:27:40 am
content: 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 tubingSince 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

author: mzzj
author_rank: Super Contributor
timestamp: May 05, 2024, 01:22:53 pm
content: 96% ethanol is still pretty thin at -40c and freezes solid at -120cAt -85 ethanol is something like room temperature cooking oil or thinner.Acetone has very low viscosity but freezes bit earlier than ethanol.

author: mzzj
author_rank: Super Contributor
timestamp: May 05, 2024, 01:30:57 pm
content: 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!

author: Doctorandus_P
author_rank: Super Contributor
timestamp: May 05, 2024, 07:26:19 pm
content: Liquid nitrogen has a pretty low viscosity.Liquid helium is even much more betterer.

author: coppercone2
author_rank: Super Contributor
timestamp: May 05, 2024, 09:32:36 pm
content: is ethanol a lot better then isopropyl alcohol?maybe I should try it first before methanol,since its safer

author: mzzj
author_rank: Super Contributor
timestamp: May 07, 2024, 04:39:21 am
content: Quote from: coppercone2 on May 05, 2024, 09:32:36 pmabout same according to thishttps://www.celsius-process.com/wp-content/uploads/2020/01/ethanol.pdfmethanol is 0,005 Pa.s vs IPA 0,011 Pa.s @-70Toluene is about same or slightly better than methanol @-60

author: Berni
author_rank: Super Contributor
timestamp: May 07, 2024, 05:31:32 am
content: 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

author: notsob
author_rank: Frequent Contributor
timestamp: May 07, 2024, 09:44:40 pm
content: 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

author: IanB
author_rank: Super Contributor
timestamp: May 07, 2024, 10:50:31 pm
content: 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?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 07, 2024, 10:50:43 pm
content: 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

author: coppercone2
author_rank: Super Contributor
timestamp: May 08, 2024, 04:13:58 am
content: Quote from: notsob on May 07, 2024, 09:44:40 pmi avoided that one for the same reason as methanol, i.e. when a hose disconnects and you get popped by a cobra

author: IanB
author_rank: Super Contributor
timestamp: May 08, 2024, 05:21:12 am
content: Quote from: coppercone2 on May 08, 2024, 04:13:58 amEthylene 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.

author: coppercone2
author_rank: Super Contributor
timestamp: May 08, 2024, 06:20:28 am
content: anther problem with viscosity is flow meters. I doubt the acrylic flow meter I have is accurate with viscous cold liquids.

author: jpanhalt
author_rank: Super Contributor
timestamp: May 08, 2024, 08:36:46 am
content: Quote from: coppercone2 on May 08, 2024, 06:20:28 amIf 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.

author: coppercone2
author_rank: Super Contributor
timestamp: May 08, 2024, 08:40:34 am
content: 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.

author: jpanhalt
author_rank: Super Contributor
timestamp: May 08, 2024, 09:18:29 am
content: 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?

author: Berni
author_rank: Super Contributor
timestamp: May 08, 2024, 09:45:52 am
content: 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.

author: Overspeed
author_rank: Frequent Contributor
timestamp: May 11, 2024, 01:16:43 pm
content: HelloBe aware ethylene glycol is a toxic chemical even at low concentration that destroy the liverAs 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 workRegardsOS

author: jpanhalt
author_rank: Super Contributor
timestamp: May 11, 2024, 01:47:39 pm
content: Yes, ethylene glycol is toxic, but its toxicity is mostly to the CNS, cardiopulmonary, and lastly kidney.https://www.cdc.gov/niosh/ershdb/emergencyresponsecard_29750031.html#:~:text=Ethylene%20glycol%20has%20a%20sweet,Ingesting%20enough%20can%20cause%20death.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5627743/#:~:text=The%20liver%20metabolizes%20approximately%2080,excreted%20unchanged%20by%20the%20kidneys.&text=Ethylene%20glycol%20exerts%20its%20toxicity,with%20central%20nervous%20system%20depression.

author: coppercone2
author_rank: Super Contributor
timestamp: May 11, 2024, 07:39:59 pm
content: Quote from: Berni on May 08, 2024, 09:45:52 amI have a gear pump but the metering devices say they use a oval gear system. I think its different for the measurement transducer vs the pump.Is there a difference? This gear pump has a shaft sticking out the back so I can definitely measure RPM, but I thought it was inappropriate and you need the oval version for sensing flow.https://ipe-pumps.com/process-equipment/does-your-gear-pump-need-a-flow-meter/

author: Berni
author_rank: Super Contributor
timestamp: May 11, 2024, 07:53:07 pm
content: Well i would guess it mostly depends on how precisely made the pump is.In theory a gear pump should be accurate because one rotation should always transfer the same amount of fluid (as long as you don't run it violently enough to have cavitation and such), but a real gear pump might have a bit looser tolerances so it might leak slightly while it is pumping, so some of the pumped fluid leaks back trough the pump itself.You should be able to test this by trying to force the fluid trough the pump while it is not spinning and see if any liquid comes trough. Or if the pump can do it, try running the pump with the output blocked off and see if the gears spin at all with no flow.The nice thing is that if it does work, it won't be dependent on any physical property of the measured fluid (like most flow meters do)

author: Smokey
author_rank: Super Contributor
timestamp: May 11, 2024, 08:04:33 pm
content: Am I really the only one interested in what OP is actually doing with this setup?If so... then coppercone2.. What are you actually doing with this setup?

author: coppercone2
author_rank: Super Contributor
timestamp: May 12, 2024, 11:41:07 pm
content: not much it does not work well its hard to get things cold like that. I just want to connect coolant to things for measuring. you can basically cool anything from a ruler to a laser diodeFor small scale, you need a shit load of insulation. if the tubes were bigger then it might work alot better with alot more flow

author: jpanhalt
author_rank: Super Contributor
timestamp: May 13, 2024, 12:36:36 am
content: You over complicate things with no purpose. In the mid-1960's we routinely did spectroscopy and a few reactions at -70 °C. We did IR spectroscopy with liquid nitrogen cooling (Nujol mulls and glasses), and a few IR studies at liquid helium (4° to 5°K).First, decide what you want to do.

author: coppercone2
author_rank: Super Contributor
timestamp: May 13, 2024, 12:48:20 am
content: ok thanks for the tip

author: coppercone2
author_rank: Super Contributor
timestamp: September 22, 2024, 06:35:02 am
content: I bought a molybdenum crucible (yikes at the price!) for low temperature experimentsI don't see a good way to do fluid experiments without more exotic materials, say a freeze crystal machine that might work with something caustic or acidic. I thought about it on and off for months! At least not one without wishy washey hopes about ions and reactivities. I think molybdenum has a chance maybe.The idea is to setup a water cooled peltier stack inside of a insulation cube, so I can chill it down as much as I can. With a beaker and thermal paste, I got to around -50C IIRC for a few mL of alcohol in a 25ml flask.I hope that with the thermal mass of the molybdenum, I can freeze crystalize some stuff like tin chloride and quickly throw it into a vacuum funnel to get some purified reagents

author: coppercone2
author_rank: Super Contributor
timestamp: October 05, 2024, 07:33:30 am
content: on a brand name stacked module, I managed to cool a 1oz nickel crucible of propylene glycol to -42 degrees Cslurpyas for my fluid cryo-cooler,I need to try making a proper circuit, i.e. pump bracket and polyiso insulation. my loop area is too big and its admitting too much heat, plus its like some weird over sized keychain. I think I shall mount it on my optics plate.I want to see the performance on the minimum loop, then see what adding 'transmission' leanght lines to it does