Study on the compatibility of natural ventilation and fire safety through An Atrium Building -Model Experiment and CFD analysis on the Efficiency of Natural Ventilation

摘要

As we all know, stack effect is always occurring in atrium buildings. Recently with people paying more attention to energy conservation and indoor air quality, natural ventilation promoted by stack effect is widely adopted. But from the view of fire safety, stack effect will easily make smoke spreading to upper part of building. In this research, opening areas, which are expected to affect the stack effect greatly is changed to control the stack effect and thus to control the spreading of smoke. Considering protection of evacuation from smoke, a prototype atrium building is suggested with a large solar chimney on top of the atrium, which is expected to promote natural smoke exhaust and accumulate smoke at an event of a fire and promote natural ventilation. In this paper natural ventilation efficiency is evaluated. Experiment is conducted on a 1/25 scale model to evaluate the efficiency of this solar assisted natural ventilation system. Several area conditions of inlet and outlet and several temperature settings are chosen to conduct experiment and simulation. The results of model experiment and CFD simulation show good coincidence with each other. With the increasing of outlet area, the position of neutral plane rises and airflow rate goes up correspondently. When surface temperatures increase, airflow rate goes up while the position of neutral plane changes hardly. Suppose the necessary fresh air volume for office buildings as 5m~3/m~2h, the total necessary fresh air volume should be about 33750m~3/h. From the results natural ventilation can almost satisfy the requirement of fresh air for office rooms when outlet is 12m~2 and inlet is 6m~2.