Improve the VAV control performance using advanced control technique

Variable Air Volume (VAV) air handling unit is generally equipped in modern commercial buildings to deal with the indoor air temperature and humidity level for maintaining acceptable indoor environment for human beings. It can vary the supply airflow rate according to the load conditions of occupied spaces, and hence more efficient in energy consumption compared with Constant Air Volume (CAV) air system. However, with the change of the supply airflow rate, the dynamics of the VAV air-handling unit is time varying and nonlinear, which increase the control difficulty. It is known that the control performance of air conditioning systems directly influences indoor thermal comfort and the reliability of building automation system, and consequently the natural environments. Therefore, it becomes necessary to improve the control performance of VAV air handling unit concerning on the efficient implementation of energy in buildings. In this paper we will describe a new technique which is developed to deal with several tough control issues in VAV air handling units. The new technique is based on the use of robust model-based predictive control. This technique can take accounts of uncertainties, nonlinearities and constraints associated with the VAV air handling unit simultaneously in the control design. We will illustrate how the proposed control strategy offers application advantages in the control of VAV air handling units.