View Full Version : Hobby project ultra low temp chest freezer

25-11-2014, 03:14 AM
Hey ya'all :-) started a project just for fun here i bought a chest freezer, got it home and didn't even plug it in before i yanked the compressor out haha my goal has been to see just how cold i can get this puppy here is a link to what I'm working with http://www.menards.com/main/p-2423889-c-7214.htm

it came with a tiny compressor probably a 1/12 hp or smaller and was charged with r600a (isobutane)

here's what i did to it: installed a new filter dryer with high side tap, 1/5hp compressor with oil cooler feeature which i plumbed to the suction return side, i then tried two refrigerants r-410a and r1270 (aka mapp-pro torch fuel, aka propylene) both gasses had simillar low temp records but the r1270 beat it by a small margin likely cause it ran a high side 75psi lower than the 410a my compressor was also a lot cooler with the r1270

anyway, my results where a record low cold room temp of -47F at about 5" of mercury suction side about 175 high side

so now my question i want to go lower. i'm feeling i might be able to put a stronger compressor in there but i gather i'm getting into the zone of needing a oil seperator (ester oil atm btw) and having too low return gas velocity to cool my compressor

I'm not sure i can get a 2 stage cascade to fit in there but i may be able to fit a auto cascade in there. what do you guys think?