**2. Case Description**

The proposed strategy was validated by an air-conditioning system in Tianjin University Laboratory. The laboratory has two floors and a height of 9 m (see Figure 1). Temperature, humidity sensors, and wind sensors were used for testing. The room temperature measuring point is installed 1 m from the ground level. The central air conditioning system has an automatic platform for monitoring and recording the operating parameters of the air conditioning system. In this case, there are two heat units with a rated cooling capacity of 42 kW and two variable frequency water pumps with a rated power of 3 kW.

**Figure 1.** Lab Exterior View.

The actual operation strategy of the chilled water system is the supply water temperature control strategy, as shown in Figure 2. When the water supply temperature is below the minimum temperature (9 ◦C), units will be turned on one by one until the temperature rises to the maximum temperature (11 ◦C). Conversely, when the water temperature is higher than the maximum temperature, units will be turned off one by one until the water temperature is lowered to the minimum temperature. In addition, the unit is equipped with a supercooling protection device, which will shut down all units when the water supply temperature is lower than the minimum temperature for more than one minute. However, in the SWT control strategy, the pump is not controlled.

**Figure 2.** The logic diagram of the supply water temperature (SWT) control strategy.

Another common control strategy is the room temperature fuzzy control strategy. As a feedback control strategy, the control strategy blurs the indoor temperature and the time change rate of the indoor temperature to solve the operation of the control equipment to ensure that the room temperature is controlled at the set value [26]. The control logic diagram of RTF is shown in Figure 3.

**Figure 3.** The logic diagram of the room temperature fuzzy (RTF) control strategy.
