Abstract: The present disclosure relates to a roof mounted modular cooling unit (“RMC unit”) which is adapted for use above a unit IT structure being used to help form a data center. The RMC unit has a housing configured to be secured perpendicularly relative to a longitudinal axis of a frame of a modular unit IT structure. The housing has a cold air discharge compartment at one end thereof, overlaying a cold aisle formed within the unit IT structure, from which cold air from the modular cooling unit is discharged into the cold aisle, and a hot air intake compartment selectively located to overlay the hot aisle, into which hot air from the hot aisle is drawn. A width of the RMC unit is sufficient to substantially span a full width of the one of the equipment racks.