Closed-loop cooling system for high-density clustered computer system

A cooling system for a high performance computing system includes a closed-loop cooling cell having two compute racks and a cooling tower between the compute racks. Each compute rack includes at least one blade enclosure, and the cooling tower includes at least one water-cooled heat exchanger and one or more blowers configured to draw warm air from a side of the compute racks towards a back, across the water-cooled heat exchanger, and to circulate cooled air to a side of the compute racks towards a front. The cooling cell further includes a housing enclosing the compute racks and the cooling tower to provide a closed-loop air flow within the cooling cell. The cooling system further includes cooling plate(s) configured to be disposed between two computing boards within the computing blade, and a fluid connection coupled to the cooling plate and in fluid communication with the blade enclosure.