Study On The Influence Factors Of Air-conditioning System Energy Consumption In High-speed Train

With the development of China's economy,the continuous expansion of the city scale and the accelerated renewal of the railway network,people's choice of travel mode is no longer limited to cars,passenger cars and planes.Subways,intercity trains and high-speed trains have become popular choices.Compared with other means of transportation,high-speed trains have a fast speed,a long running line,a large change in meteorological parameters during operation,and a higher requirement for air conditioning system(shock-proof performance,adaptability to the external environment and control of pressure)than other means of transportation.The regulations of the ministry of railways(TB1951-87)specifies the outdoor design parameters of the train air conditioning system.Based on these parameters,the designer calculates the steady-state air-conditioning load of the high-speed train,and takes the calculated value of the load as the basis of the design of the air-conditioning system of the train.However,the steady-state air conditioning load calculated in this way cannot accurately reflect the actual operating air conditioning load,and most of the calculated results deviate from the actual operating parameters.As a result,the overall air conditioning energy consumption of the train is relatively high,resulting in the waste of energy.Therefore,it is necessary to carry out dynamic calculation on the air-conditioning load of high-speed trains in actual operation,and it is also necessary to carry out energy consumption analysis on the air-conditioning of high-speed trains.Based on the basic principle of HVAC,combined with the structure and operation characteristics of high-speed train and the TRNSYS simulation software,this paperestablished a calculation model of air-conditioning load and energy consumption for the whole line of high-speed train air conditioning system,and analyzed the energy consumption rules of air conditioning in variable outdoor environment.Through calculation and analysis,it is concluded that the main factors affecting the energy consumption of the air conditioning are composed of personnel,the temperature setting value of the carriage and the outdoor meteorological parameters.Then by changing the factor level,the energy consumption of the air conditioning is analyzed,and the energy-saving optimization measures are proposed.First of all,the meteorological parameter calculation model along the Beijing-Guangzhou high-speed train is established by referring to the meteorological data of July standard day in China building standard meteorological database.On this basis,combining the standards of the ministry of railways(TB1951-87)and the operation characteristics of high-speed trains,the dynamic cooling load of air conditioning for the whole line of high-speed trains on the Beijing-Guangzhou line was obtained through theoretical calculation.It is concluded that the variation trend of total cooling load is almost the same as that of fresh air cooling load,and outdoor parameters are the important factors affecting fresh air load.Then,based on the principle of refrigeration,the factors affecting the performance coefficient of refrigerating units ? in high-speed train air conditioning system are analyzed by graphical method,that is,the influence of various factors such as the air temperature at the air side of evaporator and condenser and the load rate of air conditioning on the performance coefficient of refrigerating unit ?.Then,the correction method of the performance coefficient of the refrigerating unit ? is given in the actual situation,and the influence degree of the variation of different outdoor parameters and indoor parameters on the performance coefficient of the refrigerating unit ? is quantitatively analyzed.Finally,the energy consumption model of TRNSYS was constructed to simulate the air conditioning energy consumption results of high-speed trains under various working conditions,and the accuracy of the simulation results under typical working conditions was verified by the measured results.Using the method of single factor variance analysis and orthogonal experiment,the influence degree of each factor on theenergy consumption of air conditioning was analyzed,and the indoor parameter setting range of reducing the energy consumption of air conditioning under the premise of satisfying the thermal comfort of personnel was analyzed.The research results show that the outdoor environment parameters on the influence of the high-speed train air-conditioning system energy consumption not only embodies in the cooling load of the train,also reflect on the coefficient of performance of the refrigeration unit air conditioning system ?(i.e.effect evaporator,condenser side inlet air temperature,air compressor load factor and so on,which affect the air conditioning system coefficient of performance of the refrigeration unit ?).The effect of the change of outdoor environmental parameters on the air conditioning system is significant,but only the setting of indoor temperature parameters can be controlled manually.In the controllable range,the indoor temperature range is maintained at26~28?,which not only meets the thermal comfort requirements of personnel but also achieves the purpose of energy saving.At the end of the paper,the control strategy of the air conditioning system is given,for example,variable frequency air conditioning is used to control the indoor temperature fluctuation on the premise of meeting the energy saving requirements.