This disclosure is directed to, in one aspect, a thermal management system for a data center. The thermal management system can include an air to air heat exchanger operable in a dry mode and a wet mode. The thermal management system can also include a liquid to air heat exchanger. The liquid to air heat exchanger can have a coil that receives the cooling liquid, with the coil being positioned in communication with the air of the data center such that the cooling liquid can absorb heat therefrom. Still further, the thermal management system can include a direct expansion cooling loop with a condenser and an evaporator. The system further provides multiple combinational operating conditions among multiple cooling modes. Other aspects are described.