Airflow measurement is essential to efficiently operate air handling units (AHUs) in commercial buildings. Due to the space and cost limitations for physical meters, many virtual airflow meters have been developed for induction motor driven fan systems. On the other hand, electronically commutated motor (ECM) fans have been widely applied in AHUs. However, the applicability of virtual airflow meters to ECM fan systems remains unclear. The purpose of this paper is to develop and validate a virtual airflow meter for ECM fan systems using measured fan head and motor input power and speed. First, a virtual airflow meter model is developed by referring to an ECM fan energy model and the corresponding calibration procedure is established, then the developed model is calibrated using the manufacturer data of a 7,865 m³/h ECM fan, including fan airflow rate, head and motor input power at different motor speeds, and validated in a test AHU with an array of four calibrated ECM fans. The validation result shows that the developed meter can accurately calculate the total AHU airflow rate with the root mean squared error of 660 m³/h and the normalized root mean squared error of 4%.

气流测量对于有效运行商业建筑中的空气处理单元（AHU）至关重要。由于物理流量计的空间和成本限制，已经开发出许多用于感应电动机驱动的风扇系统的虚拟空气流量计。另一方面，电子换向电动机（ECM）风扇已在AHU中得到广泛应用。但是，虚拟气流计在ECM风扇系统上的适用性仍不清楚。本文的目的是使用测得的风扇头和电动机输入功率和速度来开发和验证用于ECM风扇系统的虚拟空气流量计。首先，参考ECM风扇能量模型开发虚拟空气流量计模型，并建立相应的校准程序，然后使用7,865 m ³的制造商数据对开发的模型进行校准。/ h ECM风扇，包括风扇流速，不同电动机速度下的扬程和电动机输入功率，并在测试AHU中通过四个校准的ECM风扇进行了验证。验证结果表明，所开发的仪表能够准确计算出AHU的总风量，其均方根误差为660 m ³ / h，归一化均方根误差为4％。