Numerical Calculation And Dynamic Simulation Of The Indoor Environment In An Office Building

With the development of global economy, people’s demands on indoor air environment are increasingly higher and higher. However, the outdoor environment is deteriorated by the highly developed industry; outdoor environment pollution directly affects the indoor environment. The urgent problem to solve now is how to improve the indoor air environment.Aiming at this problem, the air conditioning system with different ventilation methods, such as down-inlet and up-outlet, up-inlet and up-outlet, up-inlet and down-outlet of the temperature, mean age of air, PMV and PPD were calculated using computational fluid dynamics(CFD) method, and the error is within 10% by comparing the simulation values of the indoor temperature, PPD and experimental values, which shows that the mathematical and physical models of the numerical calculation is accurate. In order to analyze the influence of different ventilation modes on the indoor thermal comfort, CFD method was used to calculate the indoor flow field, mean age of air and PMV-PPD value. Additionally, based on the mass conservation equation, the indoor particulate matter mass concentration mathematical model in an office building was also established in this study, and the mathematical model was established by the means of measuring the indoor and outdoor particulate concentration and other related parameters, then the dynamic simulation model about the indoor air filtration system in an office building was set up based on the mathematical model using the MATLAB/Simulink module. By inputting the related parameters which had been identified, the relationship between the simulations data of the indoor particulate matter with the time was obtained through the dynamic simulation. By comparing the experimental measurement results and the dynamic simulation, the accuracy of the simulation model was verified. In addition, the research about the effect of the filter permeability, fresh air ratio and other parameters on PM2.5 mass concentration in the office building was made. The results show that:(1) By comparing the experimental values of the indoor temperature, PPD with the calculation values of a equation model, k ?? equation model and the indoor zero equation model, the indoor zero equation model calculation value is closer to the experimental value, the accuracy of the indoor zero equation model is verified.(2)It is concluded that the interior flow field distribution is relatively uniform with up-inlet and up-outlet ventilation mode using the indoor zero equation model, the workspace temperature is between 25 ℃ to 28 ℃, and the temperature difference is less than 3 ℃.(3) The simulation results are compared under different fresh air ratio and fixed other parameters. It is concluded that the stable value of the indoor particulate matter concentrations of PM2.5 is greater with the increase of the fresh air ratio. When the outdoor air particulate matter concentration is greater than the initial particle concentrations, the method by increasing the fresh air ratio to control indoor particulate matter is not desirable.(4) The simulation results are also compared under different filter permeability and fixed other parameters. It is concluded that the stable value of the indoor particulate matter concentrations of PM2.5 is smaller with the decrease of the filter permeability. The results show that the indoor particle concentration can be controlled by reducing the filter permeability.(5) By comparing the indoor particulate matter PM2.5 mass concentration for testing and dynamic simulation, the simulation results also show that the dynamic simulation has a certain practical value, and the indoor particulate matter concentration change trend in the office building can be better detected using the dynamic simulation presented in this study.