Study Of Integrated Adaptive Air-conditioning Terminal Units And Its Control

The energy consumption of air-conditioning terminal units occupies an important position in the entire air-conditioning system.Because the model of terminal units is selected by the design load,when the system runs at part load,the valve is needed to adjust the chilled-water volume,causing enormous loss of energy,and the control effect of the indoor environment is not always ideal.Therefore,under the background of the advocation of energy conservation and environmental protection,studying the control and energy saving methods of air-conditioning system and its terminal units is significant.For the problem of the high energy consumption and poor control effect of the airconditioning terminal,an air-water integrated adaptive air-conditioning terminal unit is invented.This unit adjusts the water volume by a pump instead of a valve,and can control the air and water volume at the same time.PI algorithms were used to write the control program,and the air-water integrated unit was proved to have good indoor comfort control effect through experiments.A simulation platform was established to study the indoor environment characteristics of air-water integrated control air-conditioning system.The results show that in full-load and part-load cases,this system can keep the indoor temperature within a deviation of 0.5℃ of supply air and return air design temperature,and creates good air distribution.The study results of hydraulic and energy consumption characteristics indicate that this system not only has a good hydraulic balance,but also can reduce energy consumption of pumps.The energy saving ratio of full-load day is 20.7%;that of part-load day and low-load day is 39.0% and 27.7%.It is shown that compared to traditional terminal and valve opening degree control,the air-water integrated unit has obvious energy-saving superiority.Moreover,the design principle and running control strategy of air-water integrated adaptive terminal air-conditioning system was summarized.The model selection of primary pump and terminal pump is essential in system design,and for this purpose,resistance loss of chilled water main pipe and branches needs to be calculated in detail.The running control strategies of this system include terminal air-water integrated control and mainfold constant differential pressure control.