Abstract : This paper introduces the principle and setting process of automatic control and energy saving of air conditioning water cooling system, describes the main program of the system, and points to note during debugging. Keywords : frequency converter; DDC; variable frequency speed regulation; control point; program In a factory in Guangzhou Economic and Technological Development Zone, its air conditioning water cooling system has four sets of chiller units (two in use and two on standby), which centrally supply cooling to the factory (see Figure 1). In order to achieve energy saving and automatic operation, a DDC digital controller is added and a frequency converter is added before the chilled water pump. Its control flow is relatively typical and can be used as a reference for similar systems. The setting principle and process are briefly described below: [align=center] Figure 1 Air conditioning water cooling system flow chart [/align] [b]1 Principle of water pump energy saving 1.1 Adjustment space is reserved in system design[/b] 1.1.1 The design water flow rate is determined based on the maximum cooling load and a 5-degree supply and return water temperature difference. However, the actual load is constantly changing, so the chiller unit operates under partial load conditions most of the time. [b][align=center]For details, please click: Automatic Control Settings and Debugging of Air Conditioning Water-Cooled Systems[/align][/b]