Hi there,
I am hoping to find out whether it is possible to modify a normal household freezer in such a way that it will be able to cool a couple gallons of water, spread out in trays, from room temperature to -40 within a few hours. Is this feasible? I was considering changing the coolant to propane, as it seems happier to go colder, then maybe changing the capillary tube? Any input would be greatly appreciated. I don't have a freezer picked out yet, since I don't know what I need to accomplish this.