Study On The Application And Optimization Of The Fresh Air System In Classroom Buildings In Elementary And Secondary Schools Of Zhengzhou

Classrooms are the main activity venues for students during school.At present,classrooms in China are mainly based on natural ventilation,but natural ventilation is greatly affected by the outdoor environment and has certain limitations.In addition,due to the serious air pollution in China,PM2.5 and other fine particles are the main pollutants outdoors,While introducing fresh air into the room through natural ventilation,it will also bring outdoor pollution into the room,it poses a threat to the health of teachers and students and cannot guarantee good air quality in the classroom.Therefore,it is necessary to provide a suitable ventilation solution for buildings like classrooms.This article combines the climatic conditions in Zhengzhou,through a combination of questionnaire survey,field test and numerical simulation,study on the actual cases of the fresh air system in elementary and secondary schools of Zhengzhou,analyze the main factors affecting classroom air quality,put forward effective measures to improve indoor air quality,provide a reference for the future development and application of classroom using fresh air system.First,analyze the current situation of classroom ventilation in Zhengzhou area in the form of questionnaire survey,The survey found,students think because of the influence of the outdoor environment,especially noise,the use of natural ventilation is limited when opening windows,and the indoor air circulation is poor.It is generally hoped that the indoor environment will be improved by enhancing ventilation and improving indoor temperature and humidity comfort,The fresh air system.can not only reduce the outdoor noise caused by opening windows,but also ensure good indoor air quality.Economic analysis of fresh air system according to the climate characteristics of Zhengzhou,The classroom which uses the ventilation system with heat recovery has a large initial investment,but the energy saving effect is obvious,the later operating cost is low,it has good applicability in Zhengzhou.Secondly,By comparing the opening and closing of the fresh air system,PM2.5and CO₂concentration in a middle school classroom using ventilation system with heat recovery is tested;calculate the natural ventilation in the classroom according to the CO₂real-time changing concentration,and use the I/O value and linear regression analysis method to analyze the correlation between the indoor and outdoor PM2.5concentrations.The results shows when the doors and windows in the classroom are closed,the amount of fresh air in the classroom cannot meet the minimum demand for fresh air in the classroom,CO₂concentration can be increased from outdoor concentration to above 2000ppm;When the doors and windows in the classroom are opened for ventilation,the per capita fresh air volume in the classroom can reach more than 20m³/h,basically meet the demand for fresh air in the classroom.Whether the doors and windows are closed,PM2.5 pollution will be relatively serious in the classroom.However,the fresh air system can effectively reduce the pollution caused by CO₂and PM2.5 and ensure good air quality in the classroom.Finally,the numerical model of classroom system is established,which are applied to simulation optimization research.The results show that the indoor CO₂and PM2.5 concentration can be effectively controlled after opening the fresh air system,the indoor ventilation and air quality are improved.It is feasible to ventilation through fresh air system,which can ensure the indoor comfort and air quality of the classroom.This paper also analyzes the influence of the position of tuyere and fresh air rate on the distribution of pollutants in the classroom.The air distribution in the classroom is more uniform and the air quality is better by the ventilation model of up-supply and up-discharge.At the same time,in order to ensure a good learning and living environment for students,fresh air volume should be around 24 m³/h.