Study On Spatial Ventilation Design Of Primary And Secondary Teaching Building In Severe Cold Regions

It is an important principle to meet the people's needs for a better life,to ensure the comfort and safety of the indoor environment,and to protect the environment and save resources.The schools teaching building is a typical place where people stay in a fixed space for a long time and the indoor air quality is poor due to insufficient ventilation.Natural ventilation is commonly used in school teaching buildings in severe cold regions of China.Meanwhile,there is a lack of effective and economical ventilation technology and measures to cope with outdoor low-temperature climate conditions.The problem of poor air quality in classrooms is particularly serious.Based on the above problems,in order to solve the reality that the classroom cannot open windows for ventilation in the classroom under the condition of low temperature outside in the cold region,this paper analyzes the ventilation situation of the buildings and main influencing factors of the ventilation by collecting the subjective and objective evaluation of the air environment,which based on the field investigation data of the teaching building in primary and secondary schools.The spatial ventilation design concept suitable for the closed period of teaching buildings in primary and secondary schools was purposed,and the spatial ventilation model of teaching buildings was constructed.By means of simulation test,the influence of spatial form of ventilation mode and ventilation opening on spatial ventilation performance of teaching building was studied.The design principle of spatial ventilation was purposed and the design process of integration of spatial ventilation and architectural design was constructed.The design strategy of teaching building based on spatial ventilation was proposed.The main contents of this paper are as follows:(1)Based on the field investigation and data collection of teaching buildings in cold regions,this paper summarized the the school buildings layout,spatial form,applied characteristics and ventilation methods,and analyzed the natural ventilation potential of teaching buildings in cold regions under the influence of climate.According to the results of investigation and analysis,the evaluation method for the ventilation performance of school teaching buildings was established,including the determination of subjective and objective evaluation indexes for the ventilation performance,on-site measurement scheme and subjective questionnaire design.(2)According to the climate distribution characteristics of typical years in Shenyang,the variation of indoor CO₂ concentration under different outdoor temperatures was analyzed.When the outdoor temperature was lower than 16?,the indoor air quality began to decline.By further measuring the air quality and thermal environment of the sample classroom,the ventilation performance of t he teaching building was evaluated.In this study,the distribution of CO₂ concentration in the classroom during school period and the corresponding influencing factors were analyzed,and the influence degree of each factor on air quality was analyzed base d on orthogonal experiment.(3)Through the evaluation of air quality and thermal environment,it is found that students'subjective feeling of air freshness is quite different from the actual measurement.By comparing the classroom temperature,relative humidity and students'heat and comfort,it can be seen that students prefer the cold environment.The actual and predicted student thermal neutral temperatures were 18.56?and19.34?,respectively.The acceptable temperature range of 80%primary school students is 16.93?21.80?,and the acceptable temperature range of 90%primary school students is 17.91?20.81?.This result provides a theoretical basis for ensuring the classroom temperature during the ventilation period.(4)According to the results of the investigation and evaluation of the ventilation condition of the teaching building,the spatial ventilation network of the teaching building was constructed and the spatial ventilation mode of the teaching building was purposed.Through field experiments,t his paper analyzes the influence of different usage patterns of the classroom on indoor CO₂ concentration under the condition of spatial ventilation,in order to reveal the spatial distribution characteristics and variation rules of CO₂ concentration in the classroom.The calculation of the minimum ventilation rate of the classroom and the prediction of the ventilation opening size based on the CO₂ concentration provide guidance for the development of the classroom opening plan and the design of simulated w orking conditions.(5)CFD numerical simulation method was used to simulate the spatial ventilation performance of the teaching building.Simulation analysis of ventilation mode spatial form classroom openings and other conditions on the air distribution of the classroom teaching building spatial ventilation volume and CO₂concentration distribution,the overall analysis of spatial ventilation performance of buildings.The mode of air intake and exhaust path,the distance between the horizontal open space and the air inlet,the air inlet temperature,the number of vertical spaces,the position and size of ventilation openings,and other working conditions are summarized.(6)Based on the current situation of ventilation in primary and secondary school buildings and the evaluation results of spatial ventilation performance,the design principles of serviceability and effectiveness of spatial ventilation are established,and the design strategies of spatial ventilation applicability are put forward.The design strategy includes the ventilation channel design strategy and the auxiliary design strategy.The design of ventilation passage mainly refers to the design strategy of applicability of the integrated design of the horizontal and vertical space of the building,the position of the classroom opening and the ventilation of the space.The auxiliary design mainly refers to the promotion strategies such as risk control system,process management,preheating and auxiliary equipment and facilities that are beneficia l to spatial ventilation.