Research On Ventilation Strategies In Newly Decorated Buildings Based On Pollutant Release And Attenuation Characteristics

With the enhancement of building closure,indoor air quality becomes worse.Especially in newly decorated room,the pollutant content in the decoration material is not up to the standard,which will aggravate the deterioration of indoor air quality and make human health threatened.Different air distribution forms will lead to different indoor diffusion and attenuation characteristics of pollutants.That is to say,they have different effects on indoor air quality.Therefore,it is necessary to put forward reasonable and effective ventilation strategies for newly decorated buildings.The research object of this article is a common office,among them the pollution source is bookcase and desk.It is joinery board besmear brush woodwork lacquer,at the same time,took into account the influence of personnel.Mainly examine indoor pollutants such as formaldehyde,benzene,toluene,xylene,TVOC and CO₂.Formaldehyde and CO₂ are released at a constant rate,while the release rates of TVOC,benzene,toluene,and xylene vary dynamically according to their characteristics.Under the same ventilation volume,the velocity field and concentration field of indoor pollutants were simulated by numerical simulation without considering heat and humidity,only the heat source and heat and humidity.Air distribution methods in this paper are side supply and upper return,up supply and lower return,bottom supply and upper return.The results showed that the indoor pollutant concentration was the highest in the up supply and lower return mode,and the heat and humidity could accelerate the diffusion of pollutants.The influence of heat diffusion was greater than that of wet diffusion,especially the influence of bottom supply and upper return mode was more significant.Different initial concentrations and diffusion rates determine the concentration distribution of different pollutants.When considering the role of heat source,the distribution of indoor pollutants,the efficiency of sewage discharge and the accessibility of pollution sources in the bottom supply and upper return mode performs better than the other two ventilation methods.The time to reach equilibrium is shortened by 7 hours compared to when the heat source is not considered.The effects of air supply speed,air supply temperature and room temperature on indoor pollutant diffusion in the bottom supply and upper return mode when heat source is considered are also explored in this paper.It was found that increasing the air supply speed can accelerate the diffusion of pollutants in the upper area of the air supply port and reduce the equilibrium concentration in the upper area.But this is not the case for the lower area of the air supply port.From the perspective of sewage efficiency,accessibility of pollution sources and energy saving,it is concluded that the indoor air quality is the best when the air supply speed is 0.3m/s for the bottom supply and upper return mode considering heat sources.When the supply air temperature is lower than room temperature,increasing the supply air temperature can effectively reduce the equilibrium concentration of indoor pollutants.Under isothermal air supply,room temperature has little effect on the diffusion of pollutants.In addition,the effect of the type of pollutants emitted simultaneously on the diffusion of one of the pollutants was studied.The results show that the emission of multiple pollutants will not affect the equilibrium concentration of the pollutants in the room.And also studied the situation of three kinds of air flow organization when releasing carbon dioxide alone and releasing carbon dioxide and formaldehyde at the same time.The pollutant concentration field,air age and sewage efficiency were compared.It is further verified that when considering the effect of the heat source,the ability of discharging the indoor pollutants by the method of bottom supply and upper return is better than the other two ways.