Part-load performance models for fans driven by electronically commutated motors in fan-powered terminal units were developed based on the analysis of data from 36 series and parallel units provided by four manufacturers. Fan motors ranged from 0.33 to 1 hp (249 to 746 W) and maximum external static pressures from 0.5 to 0.75 in. w.g. (125 to 188 Pa). Part-load performance was estimated from the intersection of the duct system and fan curves. The intersection of the two curves determined the external static pressure for estimating both fan airflow and power. Part-load airflow and power fractions were then estimated by using the airflow and power at the maximum airflow controller setting as the reference. The part-load curve tracked close to the fan law curve at airflow fractions above 0.4. The deviation between the two curves was 18.8% at an airflow fraction of 0.4 and increased at lower airflow fractions. The power consumption of motor controller may contribute to the deviation from the fan law curve at airflow fractions below 0.4. The model can estimate the part-load performance for fan-powered terminal units with electronically commutated motors in building simulation programs considering the wide range in fan motor sizes and maximum static pressures in the dataset.

在分析了四个制造商提供的36个串联和并联单元的数据后，开发了风机供电终端单元中由电子换向电动机驱动的风机的部分负荷性能模型。风扇电机的功率范围为0.33到1 hp（249到746 W），最大外部静态压力为0.5到0.75 in。wg（125到188 Pa）。根据管道系统和风扇曲线的交点估计了部分负荷性能。两条曲线的交点确定了用于估算风扇气流和功率的外部静压。然后，使用最大气流控制器设置下的气流和功率作为参考，估算部分负载的气流和功率分数。在气流分数高于0.4时，部分负荷曲线接近风扇定律曲线。两条曲线之间的偏差为18。气流分数为0.4时为8％，而较低的气流分数则增加。在气流分数低于0.4时，电动机控制器的功耗可能导致与风扇定律曲线的偏离。考虑到风扇电动机尺寸的广泛范围和数据集中的最大静态压力，该模型可以在建筑模拟程序中估计具有电子换向电动机的风扇动力终端单元的部分负荷性能。