Feasibility And Energy-saving Research On Innovative Environmental Control System Of Subway

Subway is developing rapidly because of its large transport capacity, fast speed and environmentally friendly features. The high energy consumption of subway environmental control system has received increasing attention as it proving us with convenience. Choosing a reasonable environmental control system is one of the issues which must be considered in subway construction. A lot of subway designers are in favor of automatic platform gate (APG) system and platform screen door (PSD) system due to their safety and comfort, but both APG and PSD systems have advantages and disadvantages in energy-saving efficiency: in air conditioning seasons, PSD system can reduce the air-conditioning energy consumption, but in non-air-conditioning seasons, the ventilation energy consumption is higher; in contrary, APG system's ventilation energy consumption is lower in non-air-conditioning seasons, but in air-conditioning seasons, the air-conditioning energy consumption is higher.This paper introduced an innovative environmental control system——PSD system with controllable slit, which has advantage of both APG and PSD systems. A newly-built subway station was introduced to analyze and demonstrate the comfort and energy-saving effect of the innovative system.Transient simulation on the process of one train pulling in and out of a station, two trains pulling in and out of a station at the same time was carried out by using computational fluid dynamics (CFD) method to analyze the variation of piston wind, the comfort and ventilation in the station influenced by piston wind, the result shows that the maximum air velocity of passenger activity areas in platform appears in the side door and the stairs, and the air velocity is less than 5 m/s, which can meet the comfort requirements, and the ventilation caused by piston wind can meet 5 times ventilation requirement of the station when controllable slit is open.There are 5 operation models of the new environmental control system, which are return air ventilation model, full fresh air ventilation model, mechanical ventilation model, mechanical and piston wind ventilation model, piston wind ventilation model. After analyzing the thermal environment of subway station, optimization control program was proposed according to the operating characteristics of innovative environmental control system, and energy-saving effect was calculated when the new system was installed in Beijing, Xi'an, Tianjin, Shanghai, Guangzhou, etc. The result shows that innovative environmental control system has remarkable energy-saving effect compared with traditional PSD system, but the energy-saving effect is affected by weather conditions, the longer the non-air-conditioning seasons, the better the energy-saving effect of the innovative system exhibits.The study of this paper provides a theoretical basis for the promotion of innovative environment control system.