Traditional constant air volume systems consume significantly more energy than variable air volume (VAV) systems because a constant amount of air is supplied to each zone regardless of the zone load. Due to seasonal and daily load variations, variable frequency drives (VFDs) can be installed on these constant air volume systems to reduce system energy consumption without needing to retrofit the terminal box. This paper presents the procedures for supply fan speed control and the results of its application in an office building. The results show electricity savings of 23% and gas savings of 19% over a six-month period.

Units: I-P