Abstract: A cooling unit having a liquid coolant flow through the cooling unit and a gas coolant flow through the cooling unit is controlled using a temperature signal representing a present temperature associated with equipment cooled by the cooling unit and a delayed-effect variable signal representing a variable having a potentially delayed impact on the temperature associated with the equipment cooled by the cooling unit. A thermal system model to which the temperature signal, the delayed-effect variable signal, the liquid coolant flow and the gas coolant flow are inputs is used to calculate a projected future temperature associated with the equipment. Responsive to the projected future temperature, coolant flow is adjusted to target the projected future temperature toward a set-point by adjusting the liquid coolant flow and the gas coolant flow. The delayed-effect variable signal may represent, for example, a processing workload or a current drawn by the equipment.