Research On Dynamic Thermal Comfort Evaluation Of Changchun Subway Passengers In Summer Based On Measured Data

At present,with the acceleration of urbanization in China,the traditional short-distance transportation has been unable to meet the needs of people's daily life.Subway has the advantages of fast running speed,saving land area,low noise pollution,low energy consumption,low air pollution and large carrying capacity,etc.These advantages make subway the only choice for transportation in high-density cities with population.Meanwhile,the degree of development of subway also reflects the scientific and technological level and economic strength of the country.China's first subway line,line 1,was built in Beijing in 1971,and by the end of 2019,41cities had used the subway to facilitate their citizens.China's subway construction has achieved considerable results,but its construction and related scientific research are still not mature.Especially in cold regions,the subway construction plan is not perfect.The design standard of the temperature in the public area of the subway station does not consider the difference of thermal environment between different areas in the station,and the test method does not consider the dynamic change process of passengers riding the subway.The experimental data is not representative enough.In Changchun subway to carry out the experimental study,therefore,to the subway station and internal environment,thermal comfort evaluation index is analyzed,and the subway passengers fixed relative thermal index RWI,using multiple linear regression method predicting the human body thermal comfort model,for subway design code and a hoop control system design is put forward reasonable Suggestions and provide the corresponding data support and reference.Changchun subway lines 1 and 2 were selected as test objects,and the thermal environment and thermal comfort of Changchun subway were tested from June to August 2019.The measured method was used to continuously monitor the temperature and humidity changes at the six measuring points of Dongsheng Street station:the station outside,the entrance and exit,the ticket office,the rest room,the car control room,the platform and the station hall.The temperature and humidity variation range and the average value of each measuring point were obtained.It was found that the temperature in the station basically met the standard and the humidity basically deviated from the standard.In addition to Dongsheng Street outside the thermal environment parameters to conduct a comprehensive survey of five typical station is also chosen to test its thermal environment,found that the east square station at higher temperature are part of the rules and regulations of time more than the rest of the station temperature meet the requirements,the humidity of each station still has obvious deviation from the standard phenomenon,CO₂concentration and PM_2.5concentrations all comply with the design requirements.Thermal environment of equipment and management rooms inside the subway test,found that each management room temperature and concentrations of PM_2.5are conform to the specifications,humidity and CO₂concentration is deviating from the rules of different level,lounge due to human activity of the long time with CO₂concentration levels of control room in each subway car control equipment for a long time to open and close air fresh air system can only through the door into the indoor CO₂concentration exceeds bid,ticketing office CO₂concentration conforms to the rules,so the equipment management room should be appropriate to open new fan,provide a good working environment for staff.According to the subway and passenger's movement,a method for the field test of passenger's dynamic thermal comfort is put forward.From station entry to subway ride,take four stops at a time,and then to station exit,to simulate the complete process of passengers using subway travel.There are 12 observation points from station entry to station exit.Each observation point will organize the subjects to fill in the questionnaire and record the environmental parameters of each observation point.Integrating subjective feeling of passengers and thermal environment parameters analysis found that summer Changchun subway passengers experience of each measuring point temperature change present"W",humidity change present"M"type,wind speed change present"W",CO₂concentration change appears inverted"V",PM_2.5concentrations change present"M"type,the change of thermal sensation vote value was"W",the change of thermal comfort vote value was"W".Temperature and MTS value regression analysis were used to obtain the thermal neutral temperature of each measurement point of the subway.Scatter chart regression analysis was used to obtain the expected temperature of subway station measurement points by temperature and thermal dissatisfaction rate and cold dissatisfaction rate respectively.The thermal comfort zone of each measurement point of the subway station was obtained by using 80%personnel satisfaction area.The results show that the thermal comfort of platform and carriage is poor,so it is necessary to raise the temperature or reduce the sense of blowing to meet the thermal comfort of human body.The relative thermal index RWI of the subway in summer was calculated in detail,and compared with the measured thermal sensation,it was found that RWI could not accurately evaluate the thermal comfort of Changchun subway,so the RWI was corrected to obtain the evaluation index RWI-CC applicable to the thermal comfort of Changchun subway in summer.Because the RWI is used to reflect the staff after or short stay in the area between the thermal comfort index,and considering the influence of factors is not comprehensive,so use the multiple linear regression method,through statistical analysis of data of human body heat sensation and its influence factors,the relationship between the fitting relation between independent variables and dependent variables,multivariate linear regression model,can not only evaluate the thermal comfort of subway passengers can also be used to predict the future thermal comfort,provide reference for subsequent Changchun ring control system.