A system for cooling computer systems in a room of a data center, comprising: one or more air channeling sub-systems, at least one of the air channeling sub-systems comprising: a mechanical cooling section configured to remove heat from the cooling air; and a direct evaporative cooling section downstream from the mechanical cooling section; and a controller coupled to the mechanical cooling section and the direct evaporative cooling section, the controller configured to selectively operate the mechanical cooling section and the direct evaporative cooling section in an adiabatic mode if a first set of control conditions is met and in a hybrid mode if a second set of control conditions is met; wherein operating in the adiabatic mode comprises channeling cooling air through the direct evaporative cooling section to evaporate water into the cooling air; wherein operating in the hybrid mode comprises channeling cooling air through the mechanical cooling section to remove heat from the cooling air and then channeling the cooling air through the direct evaporative cooling section to evaporate water into the cooling air; and downstream from the mechanical cooling section, a bypass of the direct evaporative cooling section, wherein the bypass comprises at least one damper coupled to the controller to regulate the flow of air through the direct evaporative cooling section. one or more air channeling sub-systems, at least one of the air channeling sub-systems comprising: a mechanical cooling section configured to remove heat from the cooling air; and a direct evaporative cooling section downstream from the mechanical cooling section; and a controller coupled to the mechanical cooling section and the direct evaporative cooling section, the controller configured to selectively operate the mechanical cooling section and the direct evaporative cooling section in an adiabatic mode if a first set of control conditions is met and in a hybrid mode if a second set of control conditions is met; a mechanical cooling section configured to remove heat from the cooling air; and a direct evaporative cooling section downstream from the mechanical cooling section; and a controller coupled to the mechanical cooling section and the direct evaporative cooling section, the controller configured to selectively operate the mechanical cooling section and the direct evaporative cooling section in an adiabatic mode if a first set of control conditions is met and in a hybrid mode if a second set of control conditions is met; wherein operating in the adiabatic mode comprises channeling cooling air through the direct evaporative cooling section to evaporate water into the cooling air; wherein operating in the hybrid mode comprises channeling cooling air through the mechanical cooling section to remove heat from the cooling air and then channeling the cooling air through the direct evaporative cooling section to evaporate water into the cooling air; and downstream from the mechanical cooling section, a bypass of the direct evaporative cooling section, wherein the bypass comprises at least one damper coupled to the controller to regulate the flow of air through the direct evaporative cooling section.