Multi-mode cooling system with pre-dehumidification

A system for cooling computer systems in a room of a data center includes a dehumidification system and an air channeling sub-system. The air channeling sub-system includes a mechanical cooling section that removes heat from the cooling air and an evaporative cooling section downstream from the mechanical cooling section. The dehumidification system may be upstream from the mechanical cooling section and the evaporative cooling section. A controller for the cooling system selectively operates the mechanical cooling section and the 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.