Planning (Chilling)

My idea is to convert a common household refrigerator into a freeze dryer.  Most refrigerators are perfectly capable of lowering the refrigerator compartment to the freezing range. In fact, most refrigerators simply draw cold air for the refrigerator compartment from the freezer compartment,  So it is possible to turn the refrigerator compartment into a freezer compartment with a few modifications

The only reason converting a refrigerator into a bigger freezer is not simple is because the control system is put in place to prevent it.  The refrigerator compartment is designed from the beginning to only get so cold.  The compressor is perfectly capable of getting much colder than the refrigerator compartment's control system will allow. At this point, we can assume that it can be done.  Since we are going to construct an entirely new control system, we don't need to worry about it at this time.

The next problem we face is whether or not the compressor can chill the freezer compartment down to the extremely low temperature needed for the cold trap.  The temperatures we need to achieve for the cold trap is beyond the design specifications of a household refrigerator. For this reason, it is necessary to replace the control system and run extensive testing to see if we can make it work.

In the case that a refrigerator compressor cannot generate low enough temperatures, we have a few tricks up our sleeve.  We can construct a 2-stage system fairly easily.  This will require an additional cooling unit and possibly a second control system. We will have to work on this as we get to it.  In any case, I have enough cooling units to make a 4-stage system.  For this reason, I am confident we can achieve some extremely cold temperatures.