Fan-powered terminal units (FPTUs) are composed of three main components: the fan/motor/controller, damper, and housing. These three components were experimentally characterized separately to determine if the overall system performance of series FPTU could be predicted by combining the models of the three components. Eight terminal units, from three manufacturers, with 8 in. (203 mm) and 12 in. (304 mm) primary air inlets were studied.

Fan airflow and power data were collected fromeight fans with electronically commutated motors (ECMs) over a range of fan speeds and discharge static pressures. Semi-empirical models were developed from the experimental data. Model variables included the nondimensional fan speed and the discharge static pressure. The resulting models had a coefficient of determination (R2) value greater than 0.99 for fan airflow model and 0.97 for power consumption model. These models can be applied to HVAC simulation programs to model variable-air-volume (VAV) systems with series FPTU.