Nah, think about it. The air conditioned hanger has already removed some of the moisture, so the cooling type will actually work better. ACs do remove humidity, but only a certain percentage. In a pinch, I've operated my transmitter sites without the desiccant. The building air conditioner removes a lot of moisture, and a compressor with a big tank will condense a lot of the moisture itself. (Just have to remember to drain it regularly.) Again: I'm no engine expert, but thinking out loud ... I'm not sure you need air at a sub-zero dewpoint. I just don't know.