I'll hold off on some and see what happens. It does seem that at a some period less than 15 years, like around 8, the fruit drops out.
g-man - as far as the AC unit, yes. All cooling units work pretty much the same - you have a condenser and an evaporator coil and a fan. As you remember from high school, when something is in a gas state, the molecules are flying around at high speeds. At colder and colder temps, they slow down until you hit absolute zero when motion stops.
So you compress a gas. The molecules can't exhibit the kinetic energy they want to, so you get heat. You need to dissipate that heat somewhere and a fridge or AC unit do it outside of the container they're cooling. That's why you have those fins on the back of the AC unit or your fridge.
Now you have a cool, low pressure liquid or gas. You pass that into a larger tube where it suddenly expands. As it does, it sucks energy (heat) out of the surroundings. You blow air over that tube and cool whatever you're cooling. So you're transferring the heat from the inside of the cooled space to the outside where it dissipates into the air.
A wine cooler or a fridge or the AC unit in your car work exactly the same way. The differences are in the relative sizes of the various components. It's easier to cool something 20 degrees F down from where it is than it is to cool it 50 degrees down. That's why your fridge is sealed so tightly but your car AC isn't - on a 90 degree day you're cooling down to maybe 70, whereas in your fridge you're cooling down to the 30s.
If your evaporator coil is too small for the amount of heat transfer you're attempting, it will ice up. But since any room AC unit you buy is sized to cool spaces way larger than most cellars, even if you push the unit past its normal range, it's not going to be too stressed. You'll blow off the Energy Star rating, but so what.
Wine coolers and ACs aren't designed to drop the temp 50 degrees or more, which is why you usually don't vent wine coolers out an exterior window. Their thermostats are willing to operate the units in the 50s and if you get 96 degree days, they're overtaxed. OTOH, a typical AC assumes a comfort zone in the 60s, so they're not sized to go farther down and they're happy to cool from the 80s to the 60s.
If you oversize the AC for the space, you get bad energy ratings but significantly more cooling power. There are guys who use regular large window ACs for meat lockers. You get an old trailer, put in a huge Fridgidaire or Kenmore, and you saved yourself a few grand that you would have spent to buy a ready-built meat locker. Meantime you're cooling way below the normal temp range for the AC. Like down to the 30s instead of the 60s.
The other thing is, most AC units tend to act also as dehydrators. It's why Con Ed says to match the cooler to the room - if it cycles on and off to much, it won't dehydrate. But for a wine cellar, that's what you want. I'm sitting in front of the AC unit right now and it's on 60 degrees. That's pretty good IMO. Some people like their wine a lot cooler - that's fine but I haven't had any problems for many years. And I also have a couple wine fridges just because I didn't have the space to build earlier.
You can get the AC unit to do extreme cooling like the meat guys want by several methods. Easiest is to tape a resistor to the probe and trick it into thinking it's a few degrees warmer than it is. Alternatively, you can just replace or bypass the thermostat. Just go to the hardware store or Home Depot, buy a different thermostat, and hook it up. If you're afraid to connect a few wires, there's a commercial product called Coolbot or something like that which will do the same thing and which is designed specifically to make an AC cool a meat locker, but you're wasting money.
Either way, it's a proven method and you can spend $100 every year and still come out ahead after 12 years vs buying something like Whisperkool.
If you want a better illustration, I think this link does a pretty good job of explaining things.
Working AC unit
