Study On Emmision Regularities Of TVOC In Wet Building Materrials And Numerical Simulation Of TVOC Concentration In Office Building

It is common in indoor decoration, using various wet building materials to decorate the house.However, the materials can release VOCs(Volatile Organic Compounds, VOCs) and have a serious impact on the indoor air quality, being the main pollutant of "building pathological syndrome"(SBS). It is necessary to do a research of wet building materials about VOC emission and propagation mechanism and it can provide a reliable basis for controling indoor pollutants and enhance the level of human health.In this study, based on PGM-7240 portable gas detector to test VOCs from wet building materials at different temperatures, relative humidity, and substrate materials in the environmental chamber. A self-designed method was appied in this article,which could measured release rate of building materials.Curves were drafted and programmed into C++,which loaded into FLUENT and can generate user-defined function(UDF).Then it could be selected as the boundary conditions in FLUENT. Based on this method, do a three-dimensional numerical simulation on three different ways of indoor air pollutants and have a numerical simulation on the accumulation of TVOC with closed time and and under different ventilation rate of ventilation in two working conditions.This subject comes from National Science and Technology Support Plan— the research and demonstration project of indoor environment control and the key technology to improve health(2012BAJ02B06). The main contents of this paper are as follows:1) In any environmental conditions, wood-paint and wall emulsioni paint release TVOC shown a consistent rule: TVOC emerged rising rapidly in the early stages of 0 ~2h, reaching a maximum rapidly, and then attenuating rapidly from the maximum concentration in 2~ 48 h,but it tended to be stable after 48 h.2) The temperature had a obvious effection on the release of TVOC from wood coatings,but it was not a consistent positive promoting effect with a rise of temperature.When it was at a higher temperature, the release rate of TVOC reduced. Unlike temperature effection, the release rate of TVOC in turn increases with the relative humidity increasesing.3)The high temperature and high humidity was more conductive to release TVOC than low temperature and low humidity, and Max(low temperature and low humidity):Max(mid temperature and mid humidity):Max(high temperature and high humidity)= 1:1.63:2.02.4)The removal efficiency of TVOC was different between three ventilation types. Under the same air volume, the displacement ventilation had a lower wind speed about 0.0275 ~ 0.055 m/s in work area and a small vortex strength than the above supply by return and the above supply in return,which can meet the requirements of human comfort.5) The cumulative concentration of TVOC were not the same in different seasons. The accumulation of the pollutants concentration in winter conditions is lower than the summer conditions. Closed the windows and doors for 15 h, the average concentration of TVOC exceeded 6.1 times under summer conditions and 4.2 times under winter conditions.In the same working conditions, the greater the ventilation rate is, the shorter the time, but not simply direct proportion. In the most adverse ventilation of winter, it speeds 8 minutes to down to the standard limit value; In the most adverse ventilation of summer, it speeds 6 minutes to down to the standard limit value.