"K W Hart" wrote

Straying away from darkrooms into air conditioners, Mitsubishi makes a two
part system: the air handler mounts inside the room, usually near the
ceiling and the compressor goes outside, like a normal whole house air
conditioner system. The systems are available in different sizes and the
compressors can handle one, two, or three air handlers. Of course with
such a unit, there is no option for outside air.

In case anyone's interested, the Mitsubishi units are called "Mr. Slim."