2005 Volume 30 Issue 99 Pages 1-9
A method of ventilation that uses a ceiling plenum in sitting room of residential houses as the route of airflow has several merits. For example, this method enables us to design higher ceiling in sitting room and to design free floor plan. However, there is obstruction for airflow inside the ceiling plenum in this method. For example, the height of the ceiling plenum is several centimeters. Furthermore, the intersections of furring strips and runners are regularly placed inside the ceiling plenum. Accordingly, for the purpose of adopting this method, it was necessary to investigate the characteristics of airflow inside the ceiling plenum. In this study, a ceiling plenum in sitting room of a detached house constructed of box frame type reinforced concrete was investigated. we mesured the condition of pressure in a full-scale model by experiment and calculated the characteristics of airflow in the same sized model by CFD analysis. The hight inside this model is 55mm, and the plain dimension of this one is approximately 8.2mx4.8m. The results can be summarized as follows: 1) The air resistance coefficient inside a ceiling plenum was caluculated by mesuring a difference of total pressure between air intake and exhaust opening in a full-scale model. As a result of experiment, the air resistance coefficient of experimental model is a little less than 2. 2) The intersections of furring strips and runners lower air velosity inside the ceiling plenum. As a result, furring strips and runners keep the static pressure inside the ceiling plenum uniform. 3) There was a good correlation between speed of air supply in air intake and static pressure. 4) The distribution of static pressure inside the ceiling plenum computed by low-Reynolds-number k-ε model had a good agreement with the experimental values. Moreover, there was no large difference in the results between low-Reynolds-number k-ε model and standard k-ε model.
