Study On Air Quality Monitoring And Ventilation Mode Of Mechanically Ventilated Residential Buildings In Liaoning Area

Good indoor air quality is an important index to ensure the physical and mental health of residents,but the problem of indoor air pollution in China is more prominent at present.On the one hand,poor inferior interior decoration materials and furniture produce a lot of chemical pollution.On the other hand,PM2.5 and other particulate pollutants enter the interior through various ventilation channels,leading to the aggravation of indoor air pollution,which seriously threatens the health of indoor residents.Therefore,it is necessary to solve the problem of indoor pollution by studying indoor air environment.Mechanical ventilation is one of the effective means to solve indoor air pollution.This paper focuses on mechanical ventilation to explore the indoor air quality and performance of fresh air systems in residential buildings under the condition of mechanical ventilation,so as to provide more suitable ventilation mode for residents in Liaoning area and ensure their health.In order to better understand and analyze the residents’ventilation behavior habits,indoor air quality and the application status of fresh air systems in Liaoning area,this paper adopts the form of questionnaire to investigate the residential buildings in Liaoning area.Taking Shenyang and Yingkou as the representative,8 residential buildings equipped with full heat recovery fresh air systems were selected.The indoor air quality data,including formaldehyde,TVOC,CO₂,PM2.5 concentrations,temperature and humidity,as well as the performance parameters of fresh air systems and other relevant information were collected and analyzed by the way of actual measurement.In this paper,the ventilation behavior habits of residents were statistically analyzed,the application effect and performance characteristics of residential fresh air system were actual tested,and the concentration level of indoor pollutants under the closed condition and mechanical ventilation condition was compared.Taking indoor PM2.5 concentration as the characteristic parameter,four combined ventilation modes of mechanical ventilation with medium and high-efficiency filtration fresh air system,mechanical ventilation with crude filtration fresh air system,mechanical ventilation with crude filtration fresh air system and air purifier and natural ventilation with air purifier were tested and analyzed on PM2.5purification effect and system energy consumption.Different types of residential buildings have different requirements for the air volume and purification capacity of fresh air systems.For the selection of fresh air systems,the Energy Plus software was used to calculate the type of fresh air system required according to the air quality design conditions.At the same time,three ventilation mode simulation schemes including natural ventilation,natural ventilation with air purifier and mechanical ventilation were set up to analyze the indoor CO₂and PM2.5concentration dissatisfaction rate and equipment purification energy consumption under different ventilation modes.The results show that mechanical ventilation and natural ventilation can reduce the concentration of indoor pollutants in varying degrees,and the change of formaldehyde and CO₂concentration is used to characterize the ventilation purification effect.Residents are accustomed to natural ventilation in summer and mechanical ventilation in winter.There are3/8 of the fresh air system’s actual supply air volume is lower than the minimum fresh air volume requirement and the particle purification capacity is insufficient.The average indoor concentration of formaldehyde under closed condition is significantly higher than that under mechanical ventilation condition,and the indoor TVOC concentration exceed the standard in each season.By comparing the four combined ventilation modes,it is found that the crude filtration fresh air system with air purifier is the most suitable ventilation mode,with the indoor PM2.5 daily average concentration of 0.033mg/m³and the daily average energy consumption of 0.894k W·h.The purification of indoor pollution by mechanical ventilation is a slow process,while natural ventilation can purify formaldehyde concentration up to 72.9%and CO₂concentration up to 54.3%instantaneously.However,in order to ensure indoor comfort,the window opening time is limited in winter in Liaoning area,and the concentration of pollutants will still rise after the external windows are closed.Keeping the fresh air system open continuously can ensure that the indoor PM2.5 concentration is maintained between0.020～0.030mg/m³,and the CO₂concentration is about 485ppm,and the long-term effect of mechanical ventilation is significant.According to the simulation results,the minimum fresh air volume of fresh air system required of the dbj1 residential building should reach 169m³/h,the annual indoor dissatisfaction rates of CO₂and PM2.5 concentration are 0%and 2.05%respectively,and the equipment purification energy consumption is 1094k W·h.In order to ensure good indoor air quality,mechanical ventilation is the most appropriate ventilation mode.By means of investigation,test and simulation,the indoor air quality of mechanically ventilated residential buildings in Liaoning area is deeply analyzed,and the appropriate mixed ventilation strategies are put forward to provide the selection basis and data support for the selection of appropriate ventilation modes for residential buildings in Liaoning area.