OR-20-C040 -- Optimizing Condenser Water Supply Temperature to Minimize Energy Usage

Condenser water supply temperature (CWST) resets are control strategies that reduce chiller plant energy consumption. Optimizing the CWST based on parameters such as outside wet bulb temperature, chiller load, and chilled water supply temperature (CHWST) setpoints can minimize total power across chiller plant components. An algorithm was developed for finding the optimal CWST for a given chiller plant. The algorithm generates lookup tables that show the optimal CWST and minimal power for a set of operating conditions. The results of the algorithm suggest three beneficial sequences of operation: resetting the CWST setpoint based on weather and cooling demand, running multiple cooling towers, and distributing chiller loads evenly.