Variable speed drive volumetric tracking for airflow control in variable air volume systems

An airflow control method has been developed for variable air volume (VAV) systems. This airflow control method is termed VSD volumetric tracking (VSDVT) since both the supply and return airflows are determined using signals of variable speed drives (VSD) instead of flow stations. Its performance is studied and compared with the fan tracking (FT) method using model simulations. For the simulation considered, the VSDVT maintains a constant building pressure and the required outside airflow under all load conditions, and reduces the annual supply and return air fan energy significantly. This paper presents the VSDVT method, the system models, and the simulation results.