Abstract: In order to realize the cold transmitting and terminal temperature adjusting of district cooling systems,a transitive theoretical model of the cold from a water system to an air system by a two-stage cooling exchange station is constructed,and by combining a dynamic change model of indoor temperature,a transfer function from the volume of the water-system primary side to the indoor temperature of the air conditioning terminal is derived.Then,the technology integrating the variable water volume (VWV) of the water-system primary side with the variable air volume (VAV) of the air conditioning terminal is applied,and according to the change of cold load,the PI and PID controllers are respectively employed to adjust the speed of pumps and fans in real-time.Moreover,the energyconsumption modeling and energy-saving analysis of the fans and the pumps are performed,so as to control the indoor temperature and save the electric quantity.Finally,by using the Simulink software,the schematic diagrams of the variation of such parameters as the indoor temperature,the pump speed,the water volume,and the energy-saving quantity are put forward,and the effectiveness of the above energy-saving control method is exhibited.

Key words: district cooling, cold, energy-saving control, variable water volume, variable air volume