Energy saving in metro ventilation system based on multi-factor analysis and air characteristics of piston vent

Energy saving contributes to sustainable development, and the fresh air induced by piston effect is closely related to the ventilation and energy saving of subway system. This paper is aimed at finding the optimal combination and energy conservation of metro ventilation system based on factor analysis and environment control system operation strategy. The numerical simulation and experiment are carried out in this paper. Firstly the variation trend of velocity field is reasonable by being compared with on-site experimental data. Secondly, orthogonal experimental design is adopted to study the major factors affecting the fresh air volume flowing into the station from the station entrance-exit, and then the optimal combination of energy saving is obtained. Next, the calculation results show that the annual electricity saving amount of the optimal combination is obviously greater than that of actual metro station and previous literature. To be specific, the maximal energy saving of the optimal combination is 236729 kW.h, while that of the actual metro station is merely 75888 kW.h. Namely the maximal energy saving of the optimal combination is about 3 times as large as that of the actual metro station. Finally, the energy saving of key factors is discussed in detail, and the results prove the energy saving increase is consistent with the rise of the blockage rate and the distance between the piston vent and the station. Besides, the optimal energy saving blockage ratio is 0.6 considering the actual blockage ratio and economic cost. According to the above consequences, innovative energy saving measures about the utilization of unorganized fresh air are proposed, which is applicable to typical subway station.