Development of Power-Based Fan Airflow Stations

Airflow measurements are critical for heating, ventilation and air conditioning (HVAC) system operations, energy conservation and fault detection. A fan-head-based fan airflow station, which determines airflow using measured fan head and speed, has been developed. However, the fan-head-based fan airflow station cannot measure the airflow associated with a flat fan head curve. To solve this problem, a motor-power-based fan airflow station is developed in this paper. The motor-power-based fan airflow station determines fan airflow using motor power and speed. Since both the motor power and speed can be directly obtained from the motor Variable Frequency Drive (VFD), no additional sensors are required for implementing a motor-power-based fan airflow station. A motor-power-based fan airflow station was implemented in a laboratory exhaust system. This paper presents the fundamental theory of the motor power-based fan airflow station and the experiment results.