Control of the outlet air temperature in an air handling unit

This paper discuss modelling and control of the inlet temperature in an air handling unit (AHU). The model is based on step response experiments made at a full scale test plant. We use gain scheduling to lower the correlation of the air flow with the process dynamic which simplify the control task. A simple way to determine the air flow with no extra equipment or experiments is suggested. Tuning of PI(D) controller based on step response identification is made using two different tuning methods. The paper describes the basic ideas, which are illustrated by simulations and plant experiments.