Overclock.net - An Overclocking Community - View Single Post - Best coolant for -40c ?

View Single Post
post #1 of (permalink) Old 02-04-2019, 05:37 PM - Thread Starter
Hydroplane
Hardware Princess
 
Hydroplane's Avatar
 
Join Date: Aug 2011
Location: Buffalo
Posts: 1,848
Rep: 38 (Unique: 30)
Best coolant for -40c ?

Hey all,

I've reverse engineered an R22 dehumidifier for chiller use. Since R22 boils at -41c I am looking for a coolant that can handle that. Not sure if the whole evaporator would get down to -41c but it certainly gets below 0c, since when I run it the water just freezes into an ice block around it.

The ideal fluid would have the following properties:
1. Freezing point of -45 or so
2. Does not get too viscous or slushy at low temps (i.e. doesn't destroy pumps)
3. Decent heat transfer (specific heat of ~2.5)
4. Does not fill house with toxic fumes
5. Non-flammable

I'm looking at the following fluids, all of them in roughly a 50/50 mix with distilled water:

1. Propylene Glycol: Non-toxic and easy to dispose of. However, I've heard it turns into slush and would basically destroy pumps due to very high viscosity at low temps. Easy to buy as RV Coolant. Not sure on the mix ratio with water they sell though. Non-flammable.
2. Ethylene Glycol: Non-fuming at least, no pets or kids in house that would drink the stuff (toxic). Is this any easier to pump at low temps? Any less viscous/slushy? Very easy/cheap to buy as antifreeze concentrate and can control ratio when mixing with water. Non-flammable.
3. Methanol: Available as windshield washer fluid i.e. Rain-X de-icer. Most of these are only available as max 35% methanol which would go down to -30c or so. However, I've read that it fumes quite badly and is obviously very toxic. I don't think I could seal my reservoir well enough that I could limit the fumes so I've more or less ruled this one out. Flows nicely at low temps, but might damage rubber & plastics. Also flammable.
4. Ethanol: Not sure where to buy this, denatured alcohol looks pricey by the gallon. E85 maybe? Nowhere near as toxic as methanol, I mean, it's basically the booze we drink lol. Probably still evaporates too easily? Also flows well at low temps but could damage plastic/seals, and is flammable.

Anyone experienced with using any of these at subzero temps? Leaning towards either ethylene glycol or ethanol. Other suggestions would be welcome too.

CHILLER DESTRUCTION
Build Log - White Voodoo
basic linux pc
(15 items)
Z390 Station
(11 items)
CPU
7980XE @ 4.3 GHz 1.10v
Motherboard
Asus Rampage VI Apex
GPU
2 x Aorus Waterforce WB 1080 Ti @ 2037/6318
RAM
Trident Z 16gb 3200c14 @ 3800c16 1.50V (the other two sticks were sacrificed)
Hard Drive
960 Evo 1TB
Power Supply
EVGA 1600 T2
Cooling
HWLabs GTR 420+280 Rads
Cooling
7 x Noctua Industrial 140mm 3000 RPM Fans
Cooling
EK D5 Pump/Res (with RGB!)
Case
LD Cooling PC-V7
Operating System
Linux Mint 19.6
Monitor
NEC PA271W
Keyboard
Razer Blackwidow Chroma V2
Mouse
Logitech M510
Mousepad
anime tiddy mousepad
CPU
9900K @ 5.4 1.50v
Motherboard
EVGA Z390 Dark
GPU
Titan RTX 2085/8500
RAM
Trident Z 3200c14 @ 4600c20 1.5v
Hard Drive
970 Evo Plus 250gb
Power Supply
silverstone 1200 from 2008 (other one exploded)
Cooling
HWLabs GTX 360 Rad (in RED)
Cooling
3x EK Vader 120mm 2200rpm Fans
Case
Dimastech Test Bench
Monitor
AOC Agon AG251FZ 240Hz
Audio
Built-in Monitor Speakers (3 watt)
CPU
Dual Intel Xeon L5520 2.26 GHz
RAM
48 GB Samsung DDR3-1066
Hard Drive
120 GB Samsung 750 Evo SSD
Hard Drive
2 TB Western Digital Green
Hard Drive
2 TB Hitachi 7200 RPM
Power Supply
650W Delta PSU
Case
1U Rackmount
Operating System
Ubuntu Server 16.04
▲ hide details ▲
Hydroplane is offline