As various strategies for improving building envelope and HVAC equipment efficiencies are increasingly used to reduce building energy use, a greater percentage of energy loss will occur through building envelope leakage. Although the energy impacts of unintended infiltration on a buildings energy use can be significant, current energy simulation software and design methods are generally not able to accurately account for envelope infiltration and the impacts of improved airtightness. The airflow analyses capabilities of several energy simulation software tools were investigated and summarized, including whether the program calculates airflow rates or considers them to be inputs. The theory behind these calculations are summarized and evaluated for their physical soundness and accuracy. A new strategy to more accurately incorporate airflow calculations into energy software is also proposed, which is based on relationships between building infiltration rates calculated using detailed multizone airflow models and building characteristics, weather conditions, and building envelope airtightness.
Citation: Air Infiltration and Ventilation Centre
Pub Type: Journals
Envelope airtightness, energy, infiltration, indoor air quality, commercial buildings