Application Of Low Temperature Radiant Electric Heating Technology In Urban Rail Vehicles

As an important part of urban public transportation,urban rail train has become one of the main means of transportation for urban residents by virtue of its advantages of large volume,convenience and speed.At present,most urban rail vehicles in China adopt the heating mode of air conditioning preheating and electric heater compensating heating,which has a large amount of energy consumption and uneven temperature distribution inside the vehicle,which affects the ride comfort.In recent years,a variety of new heating materials have emerged at home and abroad,which have been widely used in building heating.In order to further improve the comfort of the interior environment of urban rail vehicles,it is necessary to study the application of new heating materials and their application methods in the heating system of urban rail vehicles.In this paper,carbon fiber hairline is used to lay it on the bottom floor of the middle car of a B type subway in a city to form a low temperature radiative electric heating system.Firstly,the heat load inside the car was calculated to determine the total heating power of the carbon fiber generator,and the heating system was designed.Through numerical method,the structure design of the air supply duct of the carriage is carried out.Secondly,the thermal comfort in the car under carbon fiber electric heating environment is analyzed by numerical study of the temperature field in the car.The main indexes of air quality in the car were compared and analyzed by low temperature radiated electric heating and ordinary air conditioning heating,and the influence of carbon fiber electric heating on the relevant parameters of air quality in the car was studied.The annual average of initial investment cost and operating cost of the two heating modes are compared and analyzed.The economic performance of the two heating modes is compared.According to the calculation method of energy consumption of intermittent heating,the energy consumption of carbon fiber electric heating under different external gas temperature or different internal temperature requirements is calculated.The results show that the heating power required for B-type subway intermediate car is10.2k W,and the carbon fiber hair wires are laid in"S"type along the length direction of the car,with the spacing of 8cm.After the structure of the air supply duct is optimized,the uniformity of the air outlet velocity of the air duct is significantly improved.Under steady state,the temperature in the compartment is evenly distributed with good thermal comfort.Under open state,the bottom area near the door is affected by a certain cold air,while the upper area is less affected by cold air.After the door is closed,the temperature field in the compartment returns to a stable state again after 35s.Compared with the traditional air-conditioning heating method,in the carbon fiber electric heating environment,the CO₂concentration,air age,ventilation efficiency and ventilation efficiency are almost not affected,and the relative humidity and temperature efficiency of the car are significantly higher,so that the comfort of the car is improved.The comparative analysis of economy shows that the average annual investment cost and operation cost of carbon fiber electric heating system are lower than that of ordinary air conditioning units.Because of the application of intelligent temperature controller,carbon fiber electric heating system can realize intermittent heating,which further saves energy consumption,making carbon fiber electric heating more economical and energy saving.Therefore,the low temperature radiated electric heating system can be used for rail car heating,which has many advantages compared with the traditional heating method and has a broad application prospect.