Air Flow Distribution For The Air-conditioning And Ventilation Systems Of Island Platform In Subway

More and more attentions have been paid to the control of subway environment with the subway constructions going ahead rapidly in China. Because ventilation system itself became insufficient to keep the subway environment acceptable, air conditioners are widely used. However, as known to all, air conditioning system consumes a large amount of energy; an imperative duty of the researchers in subway field is to find feasible ways to save energy and to ensure acceptable air quality as well. This paper discusses mainly about the impact of different airflow distribution types on energy cost, aims to find a more efficient one.The influence of air flow distribution to two-floor island platform with transverse uniform air-supply was studied, as an example; the XiaWafang station was simulated and experimented. The main research method was the combination of field testing and CFD simulation. First, a full-scale physical model was built according to the actual size of the station, and the simulation was performed with measured boundary conditions. Then the numerical results were verified by comparing with the experiment data to confirm the reliability of the model. Last the new type of airflow distribution and the existing one were compared numerically and energy-efficiently based on the verified model.The following conclusions are drawn from this research:(1) Temperature and velocity fields simulated by CFD software Airpak are tallied with the experimental data which indicates that the simulation method is credible.(2) The original airflow organization can keep the concourse and the platform in a satisfactory temperature and airflow distribution at the specified future date.(3) The new air flow organization of zone air control can keep the concourse and the platform air quality on an acceptable leval at the specified future date.(4) Compared with the original one, the new air flow organization can save 26.2% of the air volume and 40% of the cooling load consumption at the peak period of the passenger flow in future.