From November through April my aging room, located in a separate building, is between 42 and 50 degrees.  From May on, though, when the weather warms up here in Seattle, the temperature is around 60, too warm for most hard cheeses.  I’ve looked into air conditioners, but I think the lower limit for most of them is 60 degrees.  Anybody have any ideas how I can get the temperature down to 50 in the summer?  I’ve tried putting my cheeses in a refrigerator with a thermostat set at 50 but there were too many cheeses (45) and even with a whole shelf full of water pots (with towels as wicks) the cheeses were too dry. So I’d like to try to use the aging room.

You’ve got a great problem there, Slim - 45 cheeses!  Sounds like you’re ready to go commercial.  Honestly, I can’t think of an ideal solution.  If your room is well insulated, and I assume it is, then I would think an air conditioner would do the trick, although it would also dehumidify the room in the process.  Ever think of a ThermoKing unit off a refrigerated semi trailer?  That would bring it down to below zero.

But seriously, if you plugged an AC into a thermostat, and then pinch off the AC’s thermocouple, it may just cool to below 60.  If you’re only trying to lower the room’s temp by 10 degrees, the AC should handle it quite nicely.

We talked about that before. The AC would be the quick way however if u do have some open space then covering a small room with soil to make a mound would create a well insulated cave

You can look into this, successfully used in aging room and clod storing:

Thanks for the CoolBot link.  Looks good.