The Optimization Of Variable Air Volume Air-conditioning System Control

Variable air volume conditioning system is multivariable, strongly coupled, nonlinear and time variant, so its design, performance are more difficult than constant air volume conditioning system. Recently, VAV conditioning system is more and more popular in engineering application, because of its extraordinary energy saving and comfortable features. Based on the above, the research on VAV conditioning system attracts more attentions. Nowadays, the research on VAV condition system mainly focus on stable performance and energy saving.In this paper, based on VAV conditioning system design examples, the content of VAV air conditioning control system and the problem of control theory application in the practical engineering are analyzed. There are two aspects can improve for the VAV conditioning system.For the room temperature control, air-conditioned rooms have characteristics of multi-interference, large inertia and highly nonlinear, the traditional control strategy has disadvantages in control precision, sensitivity and system stability, and also has large energy consumption. In this paper a new PID control scheme based on BP neural network was proposed. The weights of the BP network are conditioned, and then the PID parameter online adjustment is to be achieved. The simulation results show that the BP neural network PID control is more stability, smaller overshoots and shorter modeling time than BP neural network or PID control system. To the complex air-conditioning system control, the BP neural network PID control system is more suitable.For VAV air handling units, it contains more control subsystems. Because of the strong coupling among the different subsystems, the VAV conditioning system cannot run steady. In this paper, feed forward compensation method based on decoupling control has been used on the two coupled subsystems between the supply air temperature and the static pressure of duct. The feasibility and validity of the decoupling control scheme has been proved through experiment, and the results of simulation and experiment are satisfying, pave the way for the stable performance of VAV air conditioning system, which can be applied in engineering later.