Study On Air Quality Measurement And Ventilation System Optimization Of Underground Garage In Zhengzhou

In recent years,with the rapid development of China,the number of motor vehicles is increasing rapidly,and the demand for parking Spaces is also increasing year by year.Parking difficulty has become a common problem for urban residents,and various cities have vigorously developed underground garages.However,the underground garage is only connected with the outside world by the entrance and exit of the garage,and the medium and large garage cannot fully exchange air with the outside world.Therefore,mechanical ventilation has become a good choice for the full ventilation of the underground garage.Mechanical ventilation system is added to reduce the concentration of pollutants in the garage.However,according to the author’s investigation,it was found that some underground garages around him did not open the ventilation system.Based on this phenomenon,this paper studied the opening status of the ventilation system of some types of underground garages and the air quality in the garage.In this article,through questionnaire survey,field test and numerical simulation method of combining the,have not open the ventilation system of a certain complex building of colleges and universities to the underground garage actual case studies,field measurements are not when you start the ventilation system of underground garage internal pollutants concentration,takes the form of numerical simulation to investigate the underground garage outlet and the most suitable to send to decorate,Some suggestions are put forward for improving the ventilation system of the underground garage.Firstly,this paper analyzes the ventilation status of underground garages in different types of buildings in Zhengzhou by questionnaire survey.After investigation,it is found that users in commercial areas have higher recognition of the internal environment of underground garages than those in residential areas and complex buildings.In general,more than 80%of the users are dissatisfied with the air quality inside the garage or think the air quality is average.65%of the users hope to solve the problem of poor air circulation inside the garage by strengthening the ventilation inside the underground garage.Secondly,on-site measurements were conducted on the environment of underground garage in a university complex building in Zhengzhou.According to the measured results,it is found that because the ventilation system of the underground garage of the garage was kept closed for a long time,CO concentration in the breathing area of the underground garage exceeds 30ppm for more than 78%of the time and CO2 concentration exceeds 1500ppm for more than 50%of the time.Natural ventilation alone cannot reduce the concentration of pollutants in the underground garage to below the standard,where the pollutants are easy to gather in the areas near the wall and the roof of underground garage.Finally,the numerical simulation model of the underground garage is established to analyze the CO concentration field and velocity field under different air distribution mode.Based on the underground garage user activity frequency and CO concentration limit of underground garage,the necessity of ventilation system is again verified,and the most suitable ventilation method for the local garage is to select the air supply on both sides with the air exhaust in the middle.By calculating the CO emission concentration of underground garage vehicles,combined with the national development strategy of new energy vehicles in the future,it is estimated that the permeability of new energy vehicles will reach more than 78.5%in 2040,and then the design specification of underground garage ventilation system needs to be reconsidered.