Demand Controlled Ventilation in Practice: Best Practices Learned from Six VAV Systems (OR-16-C001)

Demand controlled ventilation (DCV) systems use sensors—generally either CO₂ or occupancy sensors—to estimate the actual number of people in an area and supply only as much ventilation air as is needed at that time. This can save substantial energy over the traditional method of ventilation which assumes that all spaces in a building are at peak occupancy at all times. But while DCV has been in use for over 20 years and its theoretical impacts have been well demonstrated, little is known about the actual operation and energy performance of these systems in real buildings. And even less is known about the performance of DCV for complex multizone systems. This paper helps fill this information gap by covering a field study of DCV systems that we recently conducted in multizone HVAC systems in the upper Midwest. After gathering information on a broad number of actual DCV systems installed in this region, the authors have measured, analyzed and demonstrated the impact of DCV in a subset of six such systems.