Modeling and control research of supply air temperature control systems in VAV air conditioning units

Taking a supply air temperature control system as an object, establishes the mathematical model between the opening of chilled water valves and supply air temperature based on the step response empirical identification method. In view of the large delay of temperature control systems, introduces the digital PID control with Smith prediction algorithm to improve the control quality and gives the flow chart of control algorithm. The simulating result obtained with Matlab indicates that the system has fairly robust.