This paper presents an integrated approach to controlling dry-bulb supply air temperature and outside air intake rate of an air-handling unit (AHU) by adopting a model predictive control strategy. The dynamics of the AHU are modeled with a multi-input-multi-output (MIMO) model that has a linear structure and time-variant gains. The model predictive control (MPC) controller can respond properly to different working conditions by assigning different weighting factors and constraint limits to a convex quadratic optimization problem. Weighting factors and constraint limits can be tuned in an intuitive way and their control effects are easy to understand. A building simulator was created based on the first-principle component models developed in ASHRAE research project RP-825. The simulation-based experiments demonstrated that good temperature and flow rate controls were both achieved by using MPC.

Units: SI