A vortex-producing fan controller uses a variable-speed vortex-producing fan to create a helical airflow within a server rack that couples with cooled air entering a data center through a floor opening situated near a bottom of the server rack and that draws the cooled air up through the server rack in a helical pattern. An input air temperature of air entering the variable-speed vortex-producing fan is measured using readings from a fan input air temperature sensor positioned above the server rack. A speed of the variable-speed vortex-producing fan and a flow rate of the cooled air coupled within the helical airflow up through the server rack are adjusted responsive to changes in the input air temperature of the air entering the variable-speed vortex-producing fan.