Study On Natural Ventilation Of Cooling Potential And Energy Saving In Southern Medium-sized Railway Station

As a large-scale public transportation building,the railway station is different from other building forms,It has the characteristics of large personnel density and fluidity,all-weather operation,and high proportion of glass envelope structure.Resulting in the energy consumption of the HVAC part is very large.According to the report of the National Energy Special Investigation Team,in the railway stations of southern China,the energy consumption required for air conditioning and refrigeration accounts for 37% of the total energy consumption.Therefore,how to reduce the energy consumption of air conditioning systems under the premise of ensuring the passenger comfort of railway stations has become a hot issue in the study of energy saving for railway stations.This paper takes the medium-sized railway station in the south as the research object.Firstly,based on the formation mechanism of natural ventilation,combined with the actual situation of the railway station,the factors affecting the ventilation cooling effect are analyzed,and the natural ventilation thermal comfort evaluation suitable for the railway station in the southern region is determined.Based on the main factors affecting ventilation and cooling,combined with the climatic characteristics of the southern region,the climatic zoning standards of the southern railway stations are proposed.According to this standard,the southern region is divided into five climatic zones,which are named as mild climate.Zone I,mild climate zone II,summer hot winter cold climate zone I,summer hot winter cold climate zone II and summer hot winter warm climate zone.Kunming,Guiyang,Chengdu,Wuhan,and Guangzhou were selected as the representative cities of the five climatic regions.DeST software was used for these five cities to simulate the natural ventilation conditions throughout the year in six operating conditions(only door opening,window opening ratios 0.2,0.4,0.6,0.8,and Doors and windows are fully open),and obtain the hourly temperature and humidity of the waiting room.Combined with the thermal comfort evaluation standards,the indoor high temperature hours and comfortable hours in different window opening modes are obtained.Through comparative analysis,the applicability of railway passenger stations in various climatic regions for cooling and cooling and the reasonable window opening ratio for each month in the case of natural ventilation are obtained,and on this basis,further comparison and analysis of the cooling potential of natural ventilation in typical cities in summer and the transition season under the conditions of only opening the door and reasonable opening ratio.The proportion of high temperature in summer in Kunming is 11.8%-12.7%;30.3%-31.7% in Guiyang;73.2%-79.4% in Chengdu;92.9%-94.3% in Wuhan;and 85.1%-87.7% in Guangzhou.For the areas and periods where natural ventilation cooling can not meet the comfort,a reasonable energy-saving cooling method was proposed according to the local climate characteristics,and the feasibility of the program was analyzed and verified using DeST software,and its energy consumption was compared.After analysis and calculation,it was concluded that the Kunming area can be enhanced by solar energy and basically does not consume electricity;the Guiyang area can be mechanically ventilated to assist natural ventilation,with an energy saving rate of 51.5%;Chengdu area can adopt night ventilation auxiliary air-conditioning system,energy saving rate can reach 19.5%,Wuhan and Guangzhou areas can adopt independent temperature and humidity control air conditioning systems.Compared with conventional air conditioning systems,Wuhan area has achieved an energy saving rate of 15.5%,and Guangzhou area has an energy saving rate of 16.2%.