A steady-state cooling plant model was developed for use in evaluating optimal control of ice thermal energy storage systems. The plant model calculates the power consumption of the chiller, cooling tower, pumps, and fans under an infinitely variable range of operating conditions. Given the external parameters (cooling load, ambient conditions, state-of-charge, and return air temperature) and the controls (discharge rate and temperature setpoints), the model implicitly calculates total power consumption. When embedded in the plant optimization routine, the setpoints that meet the load at minimal instantaneous power consumption can be found. Further, when this optimization is embedded in the optimal control routine, the sequence of charge/discharge rates that yield minimal operating cost over the entire simulation period can be found.

Units: I-P