An air channeling sub-system includes a mechanical cooling section and a direct evaporative cooling section. The direct evaporative cooling section is located downstream from the mechanical cooling section. Cooling air is channeled through the air channeling sub-system and into a room that receives supply air from the air channeling sub-system. If a first set of control conditions is met, the air channeling sub-systems is operated in an economizer mode. The economizer mode includes controlling an amount of return air that is blended with outside air and channeling the blended air through the direct evaporative cooling section to evaporate water into the blended air to control humidity. If a second set of control conditions is met, the air channeling sub-system is operated in a free cooling mode. The free cooling mode includes channeling cooling air to the room while the mechanical cooling section and direct evaporative cooling section are shutdown or inhibited from operation.