US Patent 10342161 System with rack-mounted AC fans

A computer system includes a chassis, one or more hard disk drives coupled to the chassis, and one or more air passages under at least one of the hard disk drives. The air passages include one or more air inlets and one or more air outlets. The inlets direct at least a portion of the air downwardly into the passages. The passages allow air to move from the air inlets to the air outlets.