Research On The Application Of Direct Evaporation Cooling Air Conditioning Cooling Technology For Bus

In recent years,the aggravation of"haze"weather makes the country very concerned about environmental problems,clear water and green mountains are gold and silver mountains.To this end,the state vigorously implement the"dual carbon"policy,to encourage everyone to reduce carbon emissions.The"double carbon"national strategic goal forces the energy saving and environmental protection of all fields and industries to be imminent.The energy consumption of the transportation sector accounts for nearly one third of the social terminal energy consumption and is still rising year by year.Traditional mechanical compression refrigeration technology has been widely used in public transport for a long time.The refrigeration technology pollutes the environment,consumes energy and has high economic cost,which provides a large space for energy conservation and emission reduction and environmental quality improvement.In this context,evaporation cooling air conditioning refrigeration technology takes circulating water as refrigeration working medium and energy consumption of pumps and fans as the cost.Its advantages of environmental protection,energy saving and low cost have been accepted by many industries and fields,especially in northwest China,where the climate is dry,subways,office buildings,restaurants and industrial plants can be seen everywhere.The application of direct evaporation cooling air conditioning to buses in dry areas will bring considerable effect of environmental protection,energy saving and air quality improvement,but it is still blank in China.Therefore,this paper takes Lanzhou as an example to study the application of direct evaporation cooling air conditioning refrigeration technology for buses.In this paper,Lanzhou a model of physical bus as an example,the first theoretical calculation method to calculate the design load of the bus is 10.8k W.Secondly,the traditional mechanical refrigeration air conditioning system and direct evaporation cooling air conditioning system are compared and analyzed,and finally revealed that direct evaporation cooling air conditioning system has the advantages of energy saving and environmental protection,low cost,good environmental air quality and so on.Then,through theoretical calculation and analysis,a direct evaporation cooling air conditioner was matched for the initial design of the bus in this paper.The size of the air conditioner was 1.1m×0.6m×1.0m,the fan air volume was 5000m~3/h,the cooling capacity was 11.9k W,the packing size was 900mm×500mm×300mm,and the headwind speed was2.4m/s.Preset in the rear of the bus carriage.At the same time,through the theoretical analysis to determine the numerical model and method in this paper,bus,with the help of a fluid simulation software Fluent and its UDF user-defined procedures,through the analysis of the thickness of the filler,outdoor air dry bulb temperature and inlet wind speed,air spray water temperature and other factors on the bus the influence of direct evaporation cooling air conditioning refrigeration performance,Thus the preliminary scheme is verified and optimized.The results show that when the packing thickness is up to 300mm and the air velocity is 2.0-2.6m/s,the refrigeration efficiency is the highest,and the increase of inlet air dry bulb temperature and the decrease of spray water temperature are helpful to improve the refrigeration efficiency of evaporation cooling air conditioning.In the end,the De ST energy consumption simulation software to simulate the bus using conventional air conditioning system energy consumption,and with it the early stage of the design of bus direct evaporation cooling air conditioning system,comparing the consumed energy ultimately bus direct evaporation cooling air conditioning refrigeration technology energy-saving rate can reach 81.12%,energy-saving effect is remarkable.