Chiller Start/Stop Optimization for a Campus-wide Chilled Water System with a Thermal Storage Tank Under a Four-Period Electricity Rate Schedule

摘要

The existence of a 1.4-million-gallonchilled water thermal storage tank greatlyincreases the operational flexibility of a campuswidechilled water system under a four-partelectricity rate structure. While significantoperational savings can be expected, thecomplication in the rate structure also requiresmore involved control over the tank charging anddischarging processes.A chiller start-stop optimization programhas been developed and implemented into theEnergy Management and Control System(EMCS) to determine the number of chillers thatneed to be brought on line and the start and stoptimes for each chiller daily, based on theprediction of the campus cooling load within thecoming 24 hours. With timely and accurateweather forecasting, the actual tank charging anddischarging process closely matches thesimulation.