使用EES（工程方程求解器）（F-Chart 2018）实施质量和能量平衡方法，以估算带有可变空气流量系列风机驱动终端装置（FPTU）的单风管可变风量（VAV）系统的年度能量性能。风扇模型基于多家制造商提供的带有电子换向电机（ECM）的风扇的性能数据。对FPTU冷却操作的两种控制方法（气流和温度）进行了评估。在这两种方法中，二次空气与一次空气混合，以在完全冷却时提供足够高的空气温度，以最大限度地减少排放调节器上的冷凝，并在低冷负荷时提供更高的温度，以减少来自调节器的冷气流。五小时内的每小时负荷- 区域建筑是使用EnergyPlus（能源部2016年）生成的。每小时的区域负荷和天气数据被用作单管道VAV系统模型的输入，使用EES估计五个城市中的五区建筑的能源使用量:休斯敦、菲尼克斯、旧金山、纽约和芝加哥。除了对气流和温度控制方法进行建模外，还通过使用ECM的容量系数，评估了FPTU相对于设计冷负荷的尺寸效应。两种控制方法都对每个城市的能源使用情况进行了类似的估计。对于容量系数为0%的FPTU，气流和温度控制方法之间的最大差异为1%。能源使用方面的这些微小差异表明，制造商在对变量进行编程时，可以采用任何一种控制策略- airflow系列FPTUs已在现场应用，并期望在性能方面取得可比的结果。这两种控制方法都比传统的固定气流系列FPTU（带永久分裂电容器）节省了大量成本。引用:2018年德克萨斯州休斯顿年会，技术论文

A mass and energy balance approach was implemented using EES (Engineering Equation Solver) (F-Chart 2018) to estimate the annual energy performance of a single-duct variable-air volume (VAV) system with variable-air flow series fan-powered terminal units (FPTUs). The fan models were based on the performance data provided by multiple manufacturers for fans with electronically commutated motors (ECMs). Two control approaches (airflow and temperature) were evaluated for the cooling operations of the FPTUs. In both approaches, secondary air is mixed with primary air to provide high enough air temperatures at full cooling to minimize condensation on discharge registers and higher temperatures at low cooling loads to reduce cold drafts from the registers. Hourly loads in a five-zone building were generated using EnergyPlus (DOE 2016). The hourly zone loads and weather data were used as input to a single-duct VAV system modelusing EES to estimate energy use for the five-zone building in five cities: Houston, Phoenix, San Francisco, New York, and Chicago. In addition to modeling the airflow and temperature control approaches, the effect of sizing the FPTU relative to the design cooling load was evaluated through the use of the capacity factor for the ECMs. Both control approaches provided similar estimates of energy use in each city. The largest difference between the airflow and temperature control approaches was 1% for the case of FPTUs with a 0% capacity factor. These small differences in energy use indicate that manufacturers could employ either control strategy when programming variable-airflow series FPTUs in the field and expect comparable results in performance. Both control approaches provided significant savings over a conventional fixed-airflow series FPTU with a permanent split capacitor.