Development of In-Situ Fan Curve Measurement for VAV AHU Systems

Currently there is no reliable and accurate method available for building pressure control due to the difficulties of accurate airflow measurement. Recently, a fan airflow station was developed that measures the fan airflow using fan head, fan speed, and fan curve. Both the fan speed and the fan head can be measured accurately using existing sensors and transducers. Therefore, the accuracy of the fan airflow station depends on the accuracy of the fan curve. An experimental method has been developed to determine the in-situ fan curve without interrupting the normal system operations. This paper presents the theoretical background, experimental methodology, implementation procedures, and verification results in the laboratory as well as existing buildings.