Study On Natural Ventilation Optimization Of Office Building Underground Garage In Hot Summer And Cold Winter Area

With the extensive use of underground garage,more attention has been paid to the ventilation problem of underground garage.Improving the utilization effect of natural ventilation in underground garage is not only an important means to ensure indoor environment health,but also a main way to promote building energy conservation.Taking the underground garage of office building in hot summer and cold winter area as the research object,this paper adopts the research method of combining theoretical analysis,experimental test and numerical simulation to analyze the influence of various factors on the ventilation performance of underground garage,and then discusses the method of optimizing the natural ventilation of underground garage.The main work is as follows:Firstly,the existing methods for calculating the CO release rate of underground garage are summarized,and the reliability and practicability of different methods are analyzed by comparing the measured and calculated data.The results show that the error of the existing methods for calculating the release rate of CO in the garage is more than 70%.Based on this,this paper presents a new method for calculating the ventilation volume of underground reservoir.The method makes the relevant parameters which affect the calculation accuracy of ventilation rate more accurate and easier to obtain in practice.The average error of the results obtained by this new method is less than 30% compared with the measured values.Secondly,an underground garage of an office building in Changsha area has carried on the field test,the test related parameters such as wind speed,CO concentration,temperature,and the distribution of statistical analysis,in order to quantify the characteristics of the underground garage environmental quality and natural ventilation through the field measurement results of this paper puts forward the calculation method of the underground garage of CO emissions,It lays a good foundation for the study of CO concentration distribution characteristics and natural ventilation characteristics of garage by CFD simulation method.Thirdly,CFD software is used to simulate the ventilation of underground garage,and the method of optimizing the ventilation of underground garage is put forward.Firstly,the wind field outside the building is simulated,and the positive and negative pressure area outside the building is determined.Based on this,the opening position of the building is changed,and four different working conditions are set.By simulating and calculating the airflow distribution and CO concentration distribution in the underground garage under different working conditions,the natural ventilation effect under different working conditions was compared,and the influence of the garage opening position change on the ventilation effect was analyzed,so as to obtain the optimal opening setting scheme.Fourthly,the wind pressure and thermal pressure coupling ventilation of underground garage were simulated by using CFD software,and the method of optimizing the thermal pressure ventilation of underground garage was put forward.The calculation principle and method of ventilation caused by wind pressure and heat pressure are analyzed,and different schemes of thermal pressure ventilation optimization are proposed for the underground garage case studied in this paper.Through CFD simulation,the distribution of airflow and CO concentration in underground garage under different schemes is calculated,and the ventilation effect of different schemes is evaluated by combining air age,ventilation efficiency and other indicators.The influence of the height and location of the patio on the ventilation effect is analyzed,and the patio setting method for optimizing the hot pressure ventilation of underground garage is proposed.