Modeling dynamic behavior of volatile organic compounds in a zero energy building

Abstract With increasing building airtightness, the design of an adequate ventilation system gains importance. The first generation of ventilation systems, based on continuous supply of the nominal airflow rate, are now being replaced by demand controlled ventilation (DCV). These systems, often H2O and/or CO2 controlled, typically do not take into account the emissions of volatile organic compounds (VOCs) to the indoor environment. A small, airtight, zero energy building that has been designed as the Belgian submission to the international Solar Decathlon competition (2011) was rebuilt afterwards in Ostend, Belgium. This building will be used as test facility for the development and validation of a holistic VOC source model. In this study, results are obtained from thermal, airflow and contaminant simulation models of the test facility to check the potential of this facility for research concerning VOCs. The different models and modeling assumptions are discussed. A dynamic VOC source model, derived from literature, is used as proxy to obtain possible VOC concentrations. The results show an important influence of temperature and humidity on the indoor VOC levels with VOC concentrations exceeding health guidelines. It is therefore important to design DCV systems and controls taking into account possible elevated VOC levels and while doing so, incorporate the dynamic behavior (influence of temperature and humidity) of the VOC emissions.