This post may be of interest if you have a fridge-sized cave in an unheated environment. My cave is a 23 cu. ft. fridge in my garage and for the last few weeks temperature in my garage have averaged less than my target aging temperature of 55F, so with the compressor not running the %RH stayed very high. By the time I figured out what was going on I was getting some off-odors (i.e. the dreaded "refrigerator smell"
) so I put a box of baking soda in the fridge and was ready to switch to my "winter" controller (a 2 stage thermostat that can cool and heat) but then realized that if the garage temperature stayed withing the temperature differential of 2 deg. (which it often does) the compressor would still not cut on.
So I thought what if I put a very small amount of heat in the fridge during the cold months and just kept it on? I put a small (7W) night-light bulb to see and it seemed to work. I logged some data (in chart below) that shows before and after the lamp was turned on.
But even though it was only 7W it made the compressor cycle too much when on, so I started thinking about how I could control the heat and add it only when needed. I realized that if I used my humidity controller to turn on the lamp that may work. I know it's counter-intuitive but when the cave temperature drops humidity will increase, so if humidity target is 85% the lamp would cut on above that, warm the fridge enough to start the compressor and then cut off when %RH drops below setpoint.
I'm out of town helping tend to a sick grand-twin but when I get back I'm going to give it a try and report results.