Stability analysis of interacting systems in air-conditioning system

Interacting systems between room air temperature of a single zone space and supply air temperature controls are considered. In air conditioning systems, the control loop can easily get into huntings. Variable air volume (VAV) control is very common for air distribution in air conditioning system today. Such interactions are assumed to be essentially to the source of huntings. To explore the possible existence of huntings, dynamical system models of the interacting systems are formulated as a bilinear model with time-delayed feedback, and a parametric analysis of the stability region is presented. Results are given showing the stability region affected by the selection of setpoint values and control parameters. This analysis is conducted to help us tune the PID controllers for achieving good control performance.