quick summary... I need to freeze a lot of dog food and do it overnight (4000lb a night normally)

this summer heat is causing problems so I was thinking about cooling the high pressure line with water before it went back into the freezer.... I've done this now with a bit of a bodge... I wrapped copper tube around the hot line and tape'd it on bloody tight... then pumped cold water through it.... but rough, but it works well, can feel the temp difference between before and after just by hand, and temps pull down much faster now

so that will work for now...

but soon all the dog food to be frozen will need to be stored in this freezer... so the original cooler unit (from the lorry) is being repaired/converted to run from the mains all the time (it broke a while back and a normal freezer unit was added to the room)

that should help bring temps down a bit quicker, and help on the hotter days...

but I'd like to drop the min. temp down a bit, at the moment it won't go below -20'C... is there anyway I can cheaply/easily drop that temp ?

I'm guessing it must be set by the expansion valve ?

thinking at the moment is that if the room has 2 separate cooler system's on it, one could run as normal to take it down to -20... and then the other could be set lower, say -30 ?...

any input/ideas anyone ?

I'll get more information on the compressors etc... asap