We claim the ornamental design for an air cooling device, as shown.
FIG. 1 is a front perspective view of an air conditioning device seen from on the top left side.
FIG. 2 is a rear perspective view thereof seen from on the bottom right side.
FIG. 3 is a front elevation view thereof.
FIG. 4 is a rear elevation view thereof.
FIG. 5 is a top plan view thereof.
FIG. 6 is a bottom plan view thereof.
FIG. 7 is a left elevation view thereof; and,
FIG. 8 is a right elevation view thereof.
The air cooling device is ordinarily installed on a roof of a server room, has a heat exchanger and a fan therein and is used to cool a server rack in the server room where computers are housed, in such a way that air is sucked from an inlet on a bottom surface, cooled through the heat exchanger and blown out from through an outlet on a front surface by the fan.