So here we go.....
20' of Copper tubing, dual pass hand coiled to fit into a 1gal cooler. The lid will not be used.
Insulated the cooler with 1" thick neoprene.
Test setup: Swiftech 355, 3/8 tubing, PSU, Kitchen Digital Thermometer, Cooper Coil, and Insulated Cooler.
Cooling Medium in Loop: 75% Anti-Freeze/25% DI Water
Liquid in 1gal Cooler (Heat-Exchanger): 3 Bottles of 91% Alcohol/1lbs of Dry Ice
Only heat being dumped into the loop is coming from the pump. This is only a Cooling Medium/Pump test to see if it will freeze at sub-zero temps or if the pump will stop operating.
Ambient Temp before starting pump
After 3 min of starting pump:
At this point temperature in the cooler is way below -50C. Cheap kitchen thermometer stopped working around -50C. Pump kept spinning but quit pumping. Liquid in the lines froze. Looks like the loop is way too effective of such a small heat load. Also, Liquid in loop needs some work.
After this test I tied strait anti-freeze but the little pump couldn't keep up because it got too thick.
Then tried 50% Anti-freeze/50% Alcohol and again the pump still issues pumping.
So finally I tried something a little different before I called it quits for the day.
Cooling Medium in Loop: 100% DI-Water
Liquid in 1gal Cooler (Heat-Exchanger): Tap Water/Ice from the freezer/1lbs of Dry Ice
This test was a success. The rig was able to maintain 0-1C for one hour with 1lbs of dry ice in the cooler before I had to drop in another 1lbs. The DI-Water in the loop did not freeze since it was just above freezing. Pump had no issues pumping. Held 0-1C for 3 hours dropping 1lbs of Dry Ice in the cooler once an hour.
Now, I do understand that adding the heat load of a CPU and two GPU cores will increase temps above 0c. Hence the reason for me first testing Alcohol/DICE. I'll like to run the Alcohol/DICE test again with a better cooling medium but am pretty sure the pump will not keep up.
What do you all think? Suggestions?
OCM
