The Influence Of Subway Piston Wind Effect On The Energy Saving Of Ventilation Air-conditioning System In Subway Station

As a convenient and efficient mode of transportation,rail transit has entered a period of rapid development with the rapid growth of national economy and the acceleration of urbanization.With the increasing demand for energy saving,it is of great significance to study the key strategies of energy conservation in metro stations,especially the key strategies of the control system.The effective use of piston wind effect can replace or partially replace mechanical ventilation to achieve energy saving.In the current represented by the subway design of environment control systems in urban rail transit,the lack of awareness of the piston effect caused by infiltration airflow in underground railway stations,in design and operation of ventilation and air conditioning systems can not properly consider the effect of natural ventilation.Therefore,it is necessary to study the use of the piston wind in the subway station to find the design and operation mode of more energy saving in the summer ventilation and air-conditioning system,so as to realize the purpose of energy saving.At first,this paper puts forward a new kind of measuring method of piston wind effect,and the use of CFD software simulation,structures,inward and outward channels model,the simulation nodes each point on the wind speed distribution show the method is feasible.From July to August in 2016,aiming to 4subway stations with shielding door knocker control system in Beijing,Chongqing,Shenzhen,Guangzhou,the field test mainly includes effects caused by the piston wind entered new air volume,unit and cooling capacity of the subway station,indoor and outdoor temperature,humidity and CO₂ concentration,etc.under the different working condition of field measurement.The CO₂ concentration distribution and the change of the station floor and platform layer were compared and tested under the condition of opening and closing of the mechanical ventilation system.Through the test,it has deepened the understanding of the natural ventilation scale of subway stations and the environmental conditions in the station,and concluded that the new air volume can meet the demand of new air quantity in the station.The air conditioning load and indoor and outdoor environment parameters were obtained during the cold season of the typical station.Analysis,even if is the subway station USES the shielding door knocker control system also has a lot of piston wind effect,using CO₂ concentration monitoring data to illustrate the summer closed mechanical air circulate in air conditioning mode is feasible.Finally to chongqing metro line 3 history station as an example,on the basis of the measured through calculation and analysis of test data in the closed mechanical air conditioning system on the cooling load end fresh air after the subway station may produce energy saving.On Beijing subway line 8 anhua bridge station,shenzhen metro line 1 deep big station,lujiang station of guangzhou metro line no.8 three station also has carried on the energy saving potential of the calculation and comparison,because each city climate conditions and the station space structure are different,So the energy efficiencies are different.However,the reasonable utilization of the piston wind effect in each city can achieve the energy saving effect,and the energy saving potential of the cold load end node is 8%to 33%.