Optimization of Occupancy Based Demand Controlled Ventilation in Residences

TitleOptimization of Occupancy Based Demand Controlled Ventilation in Residences
Publication TypeJournal Article
Year of Publication2011
AuthorsDorthe Kragsig Mortensen, Iain S Walker, Max H Sherman
JournalInternational Journal of Ventilation
Date Published06/2011
Keywordsacute to chronic exposure, airflow rates, demand controlled ventilation, equivalent dose, resave

Although it has been used for many years in commercial buildings, the application of demand controlled ventilation in residences is limited. In this study we used occupant exposure to pollutants integrated over time (referred to as "dose") as the metric to evaluate the effectiveness and air quality implications of demand controlled ventilation in residences. We looked at air quality for two situations. The first is that typically used in ventilation standards: the exposure over a long term. The second is to look at peak exposures that are associated with time variations in ventilation rates and pollutant generation. The pollutant generation had two components: a background rate associated with the building materials and furnishings and a second component related to occupants. The demand controlled ventilation system operated at a low airflow rate when the residence was unoccupied and at a high airflow rate when occupied. We used analytical solutions to the continuity equation to determine the ventilation effectiveness and the long-term chronic dose and peak acute exposure for a representative range of occupancy periods, pollutant generation rates and airflow rates. The results of the study showed that we can optimize the demand controlled airflow rates to reduce the quantity of air used for ventilation without introducing problematic acute conditions.

LBNL Report Number