Over the years, variable-air-volume (VAV) systems have become the most prominent type of HVAC system in large buildings. With growing concerns over indoor air quality (IAQ) and the fact that many VAV systems have problems meeting the newest IAQ standards (ANSI/ASHRAE Standard 62-1989), primarily in the delivery of outside air (OA) under all conditions, this project was initiated. The resulting simulation programs allow in-depth analysis of the various types of VAV systems, yielding pressure, flow, and energy information on an hour-by-hour basis. The results point out the weaknesses and shortcomings of the systems and provide guidance on how to overcome or minimize these shortcomings. From the insight gained in the study of the conventional systems, modified VAV control strategies have been developed and examined. Two of these enhanced systems show considerable promise in eliminating some of the problems inherent in the conventional systems.

Authors: Harry J. Sauer, Jr., Ph.D., P.E., William W. Delp, Ph.D.
Citation: IAQ and Energy 98 Using ASHRAE Standards 62 and 90.1 Conference Papers
Keywords: October, Louisiana, 1998