Simulation Study Of Ventilation Strategy Based On Indoor Air Quality Analysis

China has experienced rapid urbanization and economic development in the past 20 years.More than 1 billion m2 of new buildings are built every year.Artificial composites and products widely used in indoor environment will emit volatile organic compounds(VOC)that are harmful to health.Ventilation is considered to be one of the effective means to dilute pollutants.Studies have shown that the VOC emission of household building materials is a long-term process,and the characteristics of the emission process are mainly characterized by three parameters:C0,Dm and K.In the aspect of VOC emission characteristics,the influence of source characteristics,environmental factors(such as temperature and humidity)on the key parameters of VOC emission was measured and analyzed theoretically,and a very valuable conclusion was obtained.However,the influence of long-term VOC emission on its own characteristics is still unclear.In the study of ventilation strategy,more attention is paid to the ventilation mode,airflow organization form,and the minimum ventilation volume,and less research on ventilation strategy combined with source emission characteristics.In this paper,the VOC emission experiment and test of typical building materials and furniture were carried out in 3 m3 DC environment cabin.The concentration trajectory method was used to obtain the key parameters and emission model of VOC emission of test samples.The applicability of concentration trajectory method in large space scale environment cabin was verified,and the influence of material emission time on the key parameters of VOC emission was discussed.Based on the basic data obtained from the above experimental study,MATLAB programming was used to carry out the simulation study on the intermittent ventilation strategy of the office,and the effects of furniture shelf time,room load rate and fresh air volume on the pre-ventilation time of the air conditioning system were analyzed.In view of the above problems,the following relevant studies are conducted.The relevant conclusions are as follows:(1)The TVOC(Total Volatile Organic Compounds)concentration measured in the environmental compartment experiment agrees well with the curve fitted by the concentration trajectory method,so the concentration trajectory method is suitable for large-scale environmental compartments.(2)The relationship between the key parameter C0 of the dispersion and the time scale is as follows:within a certain time range,the dispersion characteristic parameter C0 of the TVOC of the experimental material plate decreases linearly from 5.5 × 105 to 1.05 × 105.The relationship between the key parameter Dm and the time scale is as follows:within a certain time range,the emission characteristic parameter Dm of the TVOC of the experimental material plate decreases first and then increases with the increase of the shelf time,and has a quadratic polynomial relationship with the time scale.(3)The simulation analysis of typical office intermittent ventilation shows that the pre-ventilation time decreases from 842min to 4min when the grounding time increases linearly in a certain range.When the holding time is constant,the pre-ventilation time increases exponentially from 2 min to 1360 min with the linear increase of furniture loading rate.When the shelving time is constant,the pre-ventilation time decreases exponentially from 1360 min to 4 min with the increase of the number of pre-ventilation ventilation.The pre-ventilation duration of continuous working days will decrease from 298 min to 188 min linear attenuation to 32 min to 18 min exponential attenuation.