A new electrical method on airflow fault detection of air handling unit (AHU)

Air handler unit (AHU) is considered as the main part of the HVAC system consuming nearly half of the total energy. Airflow blockage and leakage has become a significant problem in AHU recently. This paper describes an electrical measurement based study and mainly focuses on the airflow blockage fault detection and the estimation of insufficient airflow. It proposes a relatively simple airflow fault-detection method based on the induction machine diagnostic work. The fan torque and speed are estimated in order to get the relationship between the airflow variation and the stator current of the induction motor. A real AHU system is built to detect the airflow variance and the electrical quantities such as stator current and voltage. The obtained results show correct detection of airflow fault in AHU.