Results concerning the performance and control characteristics of the Dallas/Fort Worth (D/FW) cooling system are presented. Computer simulation models of the equipment are presented and compared with measurements for the D/FW plant. The performance associated with the use of variable-speed chiller control is compared with that of fixed speed vane control. Interactions between the control of the chiller, condensing pumps, and cooling tower fans are investigated in detail. Methodologies useful for optimal control of large cooling systems are developed.Units: I-P