Study On Human Thermal Comfort In Subway Carriage Based On LabVIEW

In the subway system,although the air conditioning system is an auxiliary system,its function can not be ignored.Because people stay in subway cars for a longer time,and the subway environment affects the comfort of passengers,even physical health.In this paper,the environment of the compartment in the subway carriage was measured,and the thermal comfort was analyzed.First of all,in consideration of the specific experimental content and the development of Lab VIEW measurement technology,a subway car thermal comfort testing and analysis system was developed in the use of Lab VIEW14.0.The system can measure and display the parameters such as the temperature,relative humidity,wind speed,globe temperature,light intensity,but also the asymmetry coefficient,ADPI,PMV-PPD parameters were calculated and analyzed.Through experimental verification,the procedure is feasible and accuracy,and it is a reliable analytical tool in the field of actual test analysis.Based on the thermal comfort testing and analysising system,the thermal comfort of the carriage in the climate chamber was studied and analyzed.After study,the carriage in full load condition,the temperature changed 24.5 to 26 degree C,changes in temperature of whole car were more uniform;velocity of the carriage was fluctuating about 0.3m/s,and in individual regions such as the air compartment at the top region and the side wall of the car parts,velocity can reach 0.6m/s,conforming to the specification.The carriage in the no-load condition,the compartment temperature and supply air temperature were almost the same,the whole carriage space temperature at 21.3 degrees C,the temperature variation of the carriage,namely the center compartment area temperature was slightly higher,while the compartment walls of a low temperature;in no-load conditions,velocity distribution the car top and side walls was high,basically at around 0.75m/s,velocity of other parts basically changed between 0.2m/s to 0.4m/s.In addition,on the basis of the thermal comfort testing system,the thermal comfort of the Shanghai subway during the winter was measured and analyzed.Through the analysis of measured for a month on the Shanghai metro line eight and line nine,respectively measured air temperature,wind velocity,relative humidity,globe temperature etc,finally concluding that the two subway lines in operation.The difference of external environment and wind velocity,relative humidity were small,the temperature at 18 degree C to 20 degree C,predicted mean vote(PMV)in-0.3 to +0.3,the predicted percentage of dissatisfied(PPD)less than 10%;and the temperature changed from 21 degree C to 25 degree,predicted mean vote(PMV)in-0.5 to +1 and the predicted percentage of dissatisfied(PPD)changing between 10% and 20%.Thus,the occupant density in the subway carriage,that is,the influence of the passenger's heat dissipating capacity on the thermal comfort is larger than air temperature supplying by the air conditioning system.