2016 ASHRAE Winter Conference

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.

The biowall is a plant-assisted air-filter that is integrated with the central HVAC system on a home to improve indoor air quality and has the potential to reduce energy consumption. The biowall concept has been evaluated in a laboratory setting and a pre-commercialization prototype has also been installed in a model home for further evaluation. This paper summarizes the laboratory and field demonstration work that has been accomplished since 2014. It is expected that a biowall can reduce the outside air requirements for IAQ by up to 50% which could subsequently reduce HVAC energy consumption by 30%.

Displacement ventilation systems have found increased usage in recent years and have been shown to reduce energy consumption while satisfying the required indoor air quality (IAQ) standard. The system takes advantage of thermal buoyancy effect to displace warm air and light containments above the occupant breathing zone. This makes the displacement ventilation system a good candidate for cooling spaces with high ceilings. Despite the advantages of this system there are still questions on the system ability in removing CO2, which has a higher molecular weight than air. The current paper investigates the CO2 concentration from occupants in an interior office with a displacement ventilation system.