the aging chamber for charcuterie

Now that I've got some bacon and pancetta curing in the refrigerator, I'm a few days away from pulling it from the salt, rinsing, and hanging it to finish the process.  To do this, one needs a suitable place replicating the environment of a mountain cave in northern Italy. (about 12C and 50% RH.. pretty much the same as storing and aging wine.. there's a reason that wine and sausage are found in the same places in the world) Short of moving to the Bay Area and digging a hole, something artificial is needed.

It seems that the popular scheme is to modify a refrigerator. One needs to keep it warmer than the normal refrigerator and one needs to deal with the humidity.  My scheme is to hook up an external temperature controller to a 4 cu ft "dorm" refrigerator I have (and pictured below), and then control humidity with a controller that controls the wet bulb temperature. Most of the writeups I've seen on the web use a humidistat and humidity sensor. And there's all this discussion about calibrating your humidistat. Heck, I've already got water in the thing AND I've got temperature sensors, so all I need to do is set a controller up to control wet bulb temp.  And somehow, I don't think this is one of those "must be controlled to 0.01%" applications.  The key is probably making the inertia of the system large (so putting stuff in that can absorb and release moisture slowly is probably the key.  Maybe rocks or bricks?)

My trusty Sanyo refrigerator, having been originally
used as a water chiller for cooling wine.

What temp?  At 55F, 50% RH is a wet bulb of about 46 degrees.  Down to 44 and you're at 40%, up to 48 and you're at 60%. Seems pretty straightforward.  Water reservoir, small pump to circulate/spray the water, and sensor that gets wet.

There should also be a fan to circulate the air in the box. That's easy, I've got boxes of old muffin fans around.

Some issues that I have to figure out:
1) short cycling the compressor is bad. I need to make sure the temperature controller doesn't cycle too short. I think with enough thermal mass on the freezer "coils" (really a plate) that will be ok.
2) Defrosting - Humid air, cold freezer coils. I think frost is inevitable.  Maybe a timer that turns it off for a couple hours a week? (that's basically what auto defrost refrigerators do).  Maybe a heater on the freezer plate?  And then I have to figure out how to keep the water that drips off the freezer from hitting the salumi, etc. hanging under it.

Psychometry
Here's my Psychometric table, which I manually read off a chart and transcribed at the stunning precision of 1 degree F. (I'll have to convert to C eventually)
dry bulb  RH  wet bulb
50    40    40
55    40    44
60    40    48
65    40    52
70    40    56

50    50    42
55    50    46
60    50    50
65    50    54
70    50    58

50    60    44
55    60    48
60    60    52
65    60    56
70    60    61