Hi there,
I am an Engineering student working on a project which requires a cold trap. The plan, as it stands at the moment, is to hack open a freezer, or a refrigerator, or whatever I can get my mitts on dirt cheap, and try and bend the evaporator coils around, then shove them into an insulated tube. The idea being that water passed through will condense on the coils, and not go through my system. Thing is, I need these coils to reach a temperature of hopefully about -40F (the lower the better) Without going into cascade refrigeration, does anyone know how this can be done? If I just stuff normal coils out of a refrigerator or something, how cold will it get if left on continuously?