Trends in airflow design and management, contributions by IEA Annex 20.

What does the designer of a future energy-efficient building ask of the air flow specialist? - Static predictions of air flow patterns and optimization of thermal comfort and indoor air quality at design conditions will not be enough for him. The paper suggests that time-dependent air flow simulation is imperative to respond to tomorrows design needs. Different physical timescales for air flow patterns in spaces will be discussed. Heat capacity by components, different types of heat transfer, varying occupancy, control inputs etc. give rise to disparate time scales. The trend toward occupant controlled ventilation will continue. Air Flow will interactively be adjusted to changing needs in each room. The IEA Annex 20 examines tools to predict steady air flow patterns within buildings. The dynamic management of air flows will require new methods that build on Annex 20 work.