The energy consumption of central air-conditioning water systems in public buildings accounts for a high proportion of their total energy consumption. The optimal start and stop strategy for each device and the settings of the control parameters play a key role in the system energy saving. In this study

a start-stop optimization strategy for the chiller and water pump and the global optimization method for the control parameters is proposed while aiming to satisfy the terminal cooling load and to minimize the total energy consumption of the system. The chilled water supply temperature and cooling water flow were considered as independent control parameters

and an energy consumption model of the central air-conditioning water system was established. The change in cooling load in one example building was simulated using DeST software

and the proposed optimization method was verified. The results indicate that the average coefficient of performance of the chiller was improved by 10.9%

the average energy consumption was reduced by 8.9%

and the average energy consumption of the water pump was reduced by 18.6% within the load rate range of 5% to 100%. On typical summer days

the central air-conditioning water system saves energy consumption by 20.4% on average.