Study On Impact Of Ventilated Double-skin Facade On The Indoor Thermal Environment In Diffferent Seasons

Ventilated double-skin fa ade (VDSF) is not only esthetic, but also characterized byenergy-saving, which is due to insulating effect in summer and that of heat preservation in winter.VDSF adopted to improve the effect of indoor thermal environment is closely related to itsreasonable use. Hence, the study of VDSF influencing on the indoor thermal environment indifferent seasons is of great significance.In this study, an actual office building with VDSF as envelope in Tianjin has been selectedas the foundation to set up the experiment system of the indoor thermal environment.Experiments aiming at acquiring the influences of VDSF on the indoor thermal environment indifferent seasons all year had been done. During summertime, thermal environment experimentsaffected by solar radiation intensity, whether there is VDSF or not, the airflow window ofexternal fa ade is open or not, the height of VDSF, and whether there is a sun-shading device inthe channel of VDSF, etc. are carried out. During wintertime, thermal environment experimentsaffected by solar radiation intensity, the airflow window of internal fa ade is open or not, and theheight of VDSF, etc. are investigated. During transitional seasons, experiments focused on thesolar radiation intensity, the use of airflow windows of both external and internal fa ade and theheight of VDSF, etc are tested and analyzed.Based on experimental data in different seasons all year, the variation of air temperature inthe channel of VDSF depends on the intensity of solar radiation. Further, in sunny days, theindoor thermal environment of rooms with VDSF is more comfortable than that of roomswithout VDSF. In summer the VDSF can reduce the average indoor temperature about1℃, inwinter it can increase the average indoor temperature about0.85℃.The air temperature ofchannel influenced by solar radiation increases with the height of fa ade increasing. Resultsshow that the correct application of DSF. It is revealed that airflow windows of external fa adeboth at top and bottom should be open in summer daytime, so that a ventilation cycle betweenthe channel and outdoor should be formed. Additionally, sun-shading device should be used in sunny days. In sunny days of winter, the airflow windows of internal fa ade should be open,leading to a ventilation cycle between the channel and indoor room is formed. Furthermore, theairflow windows of internal fa ade should be closed in other conditions. Finally, the outdoor airheated by solar radiation flowed into the indoor room though the bottom airflow windows ofexternal fa ade and the airflow windows of internal facade during sunny days of transitionalseasons, can not only improve the indoor thermal environment, but also can meet the demand ofpeople on fresh air.Based on numerical method of CFD, the height variation of VDSF influencing on theindoor thermal environment during summertime is simulated by means of Fluent software. Theresults of simulation show that, the height of fa ade which is fixed on7.2m is optimum withobviously improving the indoor thermal environment. The results of simulation can providereferences to rational use and design of VDSF for further studies.