Airtightness impact on energy needs and airflow pattern: a numerical evaluation for mechanically ventilated dwellings in France

ABSTRACT

This paper aims to assess the impact of the envelope airtightness on both heating needs and airflow patterns for the case of a single-detached dwelling as function of the ventilation system. An original numerical approach based on the energy simulation tool TRNSYS coupled to the multi-zone airflow and contaminant transport model COMIS was used to compare the performance of four mechanical ventilation strategies. The impacts of the envelope leakage location (facades and/or ceiling), the zone configuration (one- or multi-zone model), the climatic and wind exposure conditions (exposed or surrounded by obstructions) were also investigated. The results show a significant increase of the heating needs when the air permeability at 4 Pa is increased depending on the climatic conditions. Furthermore, the desired airflow pattern, and hence the dispersion of pollutants from main rooms to service rooms can be significantly disturbed especially in the case of humidity-sensitive ventilation system.

KEYWORDS:

• Airflow
• airtightness
• ventilation system
• energy efficiency

Acknowledgments

This work has been financed by the French Ministry of Housing. The sole responsibility for the content of this publication lies with the authors. It does not necessarily reflect the opinion of the Ministry.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was financed by the French Ministry of Housing supporting the development of knowledge about energy efficient building.

Notes on contributors

F. Richieri

Fabrice Richieri, after a career as researcher for the ministry of sustainable development, is currently an HVAC designer and building energy expert for the French civil aviation authority (SNIA).

B. Moujalled

Dr. Bassam Moujalled is a researcher at Cerema. His research interests include buildings energy efficiency, air infiltration, energy efficient ventilation, thermal comfort, and buildings occupancy.

T. Salem

Dr. Talal Salelm is an associate professor at NDU-Louaize University. His research interests include sustainable building design, energy conservation for buildings, solar energy integration and indoor air quality.

F.R. Carrié

Dr. Fran¸ois Remi Carrie is an international expert in air leakage and ventilation thematics at ICEE.