2001 Volume 26 Issue 80 Pages 19-26
Consideration must be given to the rates and paths of airflow when designing an airtight house in order to prevent possible future problems of air quality. In winter, an airtight house that uses heating can be easily ventilated by a passive ventilation system. On the other hand, an alternative system, such cross ventilation, must be used in summer. In this study, characteristics of the rates and paths of airflow due to the stack effect in winter and the buoyant effect in summer were discussed. The rates and paths of the passive ventilation in an airtight test house were measured by using the multiple tracer gas technique. The following conclusions were drawn from the results of this study. 1) A vertical duct and earth tubes are useful for a passive system. The uses of small fans installed between rooms and a vertical duct reduce the amount of used air, and they help the passive system. Each fan supplies the required ventilation rates into each room and also relieves thermal discomfort at the floor level. 2) Sufficient airflow rates due to the buoyant effect in summer can be expected when a roof window over the attic space is opened, and the buoyant ventilation will improve the thermal environment in summer.
