Analysis and optimization of ventilation systems for an underground transport interchange building under regular and emergency scenarios

The work and conclusions gained from the analysis of five new underground interchange buildings ongoing in Madrid, Spain, is presented. An additional study was performed for a typical two-level interchange building, and the methodology and results are presented in this paper.First, different ventilation and air conditioning strategies have been analyzed. The main goal is to find the most efficient design in order to maintain pollutants concentration and temperatures below the designed values, at minimum investment and operation costs. Different strategies have been modelled and compared using a Computational Fluid Dynamics (CFD) code, taking into account the buses circulation and the different pollution and heat sources. The final solution developed is based on a physical separation between the island area and the dock area. Conclusions on the efficiency of the different design strategies and possible pitfalls are presented.Secondly, different fire scenarios are analyzed. The main goal is to check whether the fire fighting measures planned, such as mechanical ventilation and a curtains system to define smoke sectors are able to cope with a fire emergency situation. A model for the bus fire has been developed, including heat release and smoke production. The main results presented are temperature fields, visibility and smoke concentration.