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Sub Zero Acetone Loop

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I've searched the forum and several others, however have not found an answer.

Has anyone used a closed acetone loop for cooling?

almost a decade ago i played around with chill boxes and gloycol/methanol cooling fluids and could never really achieve sufficient flow from pumps at the time at below about -15c.

Recently i've been thinking about building a new project and given the advancements in blocks and materials i'm wondering if a closed acetone loop is finally do-able. So am curious if anyone has used acetone in a loop yet?
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Acetone will destroy all gasket material I am aware of.
Acetone is specifically used as a solvent.
 

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Ethylene-propylene o-ring material is extremely good resistance to Acetone and is usually quite cheap. They typically have a temp range of -53c to +149c too. If you can find out the sizes of all the o-rings in your pump, reservoir, and fittings you can replace all of them with the EPDM o-rings. You can probably buy some of that material and custom make a gasket for CPU and GPU blocks too.

edit:
You can buy a sheet of EPDM rubber here in the thickness you need to custom cut a gasket:
 

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Ethylene-propylene o-ring material is extremely good resistance to Acetone and is usually quite cheap. They typically have a temp range of -53c to +149c too. If you can find out the sizes of all the o-rings in your pump, reservoir, and fittings you can replace all of them with the EPDM o-rings. You can probably buy some of that material and custom make a gasket for CPU and GPU blocks too.

edit:
You can buy a sheet of EPDM rubber here in the thickness you need to custom cut a gasket:
I know you are discussing a closed system. But be very careful - acetone poses a real fire risk. It can easily be ignited from its vapor. There is a demo on Youtube. Because it has a lower specific heat than water, I would expect a cooler with acetone to be less efficient than a water based one.
 

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Discussion Starter · #6 ·
EPDM is a common o-ring material (often in mass produced blocks already) and has satisfactory chemical compatibility and wide availability. Even EPDM tubing is widely available now as well. in reality the tempretature rating is more of a challange, which probably requires teflon o-rings to work with dryice bath tempreature ranges that i plan for. but even teflon o-rings are widely available. Glass+acetal for reserviors and blocks are also satisfactory chemical compatiability with acetone. Even standard D5 pumps have PPS-GF40 impeller material which has satisfactory chemical compatibility with Acetone.

At the end of the day no closed loop system is ever maintainace free. And the right solvent safe materials to build the loop are decently common. and as for concerns of vapour flash over, its only a problem if there are leaks in the closed loop and ignition sources as well as vapour in the reserviour, all of which can be minimized or eliminated.

As for efficiency, heat transfer is far less a problem than viscosity at -50 for a closed loop. which is why ethanol and isopropyl alcohol are not a good choice either from my experience with DICE and pumped liquids.
 

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Run two separate coolant loops with a heat exchanger between them. Separating the loops gives you two separate pumps/flows/temperatures to control and it lets you run two different coolant types as well since they don't mix.
 

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I'm sure someone's used it in a loop, but I've never seen it. Acetone/dry ice is the standard -78C cold bath mixture though and I've used it for this purpose.

PFTE gaskets and other common materials that could be used to assemble a loop will endure protracted exposure to acetone, as you've noted.

I wouldn't downplay the potential for leaks, especially at more extreme conditions, and wouldn't use acetone in something that I expected to leave unattended...unless I had exhaustively leak tested it first.
 

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All jokes aside ( even with my meme above ), I would test this on old equipment I do not care about ruining, or possibly blowing up in the event something bad happens. Definitely in a controlled environment with a nice big dry chemical fire extinguisher sitting next to the rig. Reason I say this, and it may be a bad example but a realistic one, Acetone is one of the main ingredients in methamphetamine production. Look up meth lab explosions, and it doesn't take much, and one minor mistake to cause havoc. All it takes is a little vapor to escape, there's allot of vapor pressure in Acetone, and god forbid there's any static discharge, or any kind of spark, you got a nice pc bomb on your hands. Good luck and be safe with whatever route you take.

I would play with Liquid Nitrogen and those dangers, before I would play with Acetone, just for avoiding the fire, and the vapor explosion risks associated with Acetone.
 

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Discussion Starter · #10 ·
Run two separate coolant loops with a heat exchanger between them. Separating the loops gives you two separate pumps/flows/temperatures to control and it lets you run two different coolant types as well since they don't mix.
Heat Exchange loops does not solve the the viscosity problem with non volatile cooling fluids. I'm not sure this helps me?
 

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Discussion Starter · #13 ·
Thanks Speed. I think you mean Novec Engineered Fluids from 3M?
My experience is they are super hard to get hold of and have some awkward material compatibility issues.
Do you remember the thread maybe it points to a supply source?

Id say the 7100 series fluid would be the pick, for dry ice applications, do you remember which fluid was used?
 

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Discussion Starter · #14 ·
Well Novec fluids are too hard to get it seems. so back to Acetone Loop Planning.

Thinking closed acetone loop inside a custom nitrogen flooded cool box with the loop connected to cooling coils in a large ethanol dry ice bath.

now to wait for LGA1200 processors and look for cheap GPUs...and think about ram cooling.
 

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Heat Exchange loops does not solve the the viscosity problem with non volatile cooling fluids. I'm not sure this helps me?
tl;dr, You need a way to get your -160°C liquid nitrogen into ethylene glycol that freezes at -65°C. So running it through acetone is the solution because it freezes at -95°C (and has less water molecules) and will allow you to transfer the cold in stages preventing icing/gelling/clogging, rather than applying extreme cold directly to ethylene glycol.

The reason I suggest using two loops is to prevent ice from forming/clogging at the phase-change heat exchanger, because that's where the coldest temperature in the whole system is going to be, so it's the location that the ice will form first. The symptoms of ice clogging your phase-change heat exchanger will look very similar to your cooling fluid having too high of a viscosity, i.e. being unable to be pumped efficiently, because the ice is restricting coolant flow.

Imagine pouring liquid nitrogen on a small copper coil/heat exchanger with ethylene glycol running through it. The coolant will ice up and clog the heat exchanger before getting cold enough for the viscosity of the coolant to make a significant difference to the flow. As ice forms, flow reduces, making more ice form... The problem is that you can't get enough flow to completely prevent ice from forming, so it'll happen sooner or later as long as the initial cooling source is colder than the freezing temperature of the fluid you're using. (Point sources of extreme cold will freeze the water molecule separately of the ethylene glycol molecule, so having a point cold source of less than 0°C risks ice forming in a ethylene glycol/water solution. A uniform extreme cold is what ethylene glycol is rated/tested for, like when the outdoor air temperature is very low, but not for when it's running through a heat exchanger acting as a point cold source that's significantly colder than water's freezing point,)

Now imagine tempering the liquid nitrogen by having it cool another coolant that doesn't ice up as easily (acetone), and then having that coolant cool a separate coolant loop with ethylene glycol in it to make it less dangerous running through your components. The liquid nitrogen won't ice up the acetone as easily, so you'll be able to modulate the application of cold better without icing up.

I don't know if you've been using liquid nitrogen, or a refrigerant/freezer, but direct application of extremely low temperatures on ethylene glycol will freeze it up/form ice crystals which clog everything, thus reducing flow, which then leads to even more ice crystals.

So my point is that tempering your cooling source though a primary loop running acetone, and then through a secondary loop running ethylene glycol, will allow you to control the differential temperatures better to prevent your ethylene glycol from icing up, and therefore not experience issues with ethylene glycol's "viscosity" problem you say you're experiencing, which I would bet is not really that it's too viscous, but that it has gelled/iced up and restricting flow at a single point.

A separate loop is for preventing icing, but also for safety. Ideally you don't want to run acetone though your components because you're dealing with multiple seals and what not, increasing the risk of a coolant loop leak/breach and the additional fire safety risk in addition to that running a volatile coolant through something that needs to be serviced. You can solder/braze your entire acetone coolant loop, and have it separated from the components and electrical sources, which also allows you to lower the volume of the acetone loop if it's only purpose is transferring the cold from the liquid nitrogen/refrigerant to the ethylene glycol.
 

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CL3D20 did a acetone loop worked pretty good as I remember, found a thread with a link to the thread but not getting a result from OCN!
 

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Discussion Starter · #17 ·
Thanks!

this has been slowly going along. i have all the needed acetone compatible components now. But i still have to make some enclosures and a cooling coil. after some testing it looks like it will be best to have a large dry ice and acetone bath and a seperate closed acetone loop with a cooling coil.

if anyone has suggestions on a large 2-4L wide top thermos ideally stainless steel please let me know!
 
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