Research On The Design Strategy Of Natural Ventilation In Underground Commercial Buildings

With the rapid development of urbanization,it is difficult to reconcile the contradiction between land resources and population growth.The development of urban underground space has become an important part of urban development.Underground commercial buildings are the most frequently used type of underground buildings.Due to the closedness of the space,there are dilemmas of low indoor wind speed,low air quality,and uncomfortable thermal environment.In order to solve the dilemma,fresh air systems are currently used for mechanical ventilation,ignoring natural ventilation.The role of.Natural ventilation can not only improve the indoor environment,but also reduce the energy consumption caused by equipment operation.Therefore,natural ventilation research will definitely become an important direction for the green development of underground commercial buildings.This article takes the underground commercial building as the research object.Based on the reasonable selection of the experimental platform and simulation process,extensive investigations and related design specifications determine the size and layout of the typical model of the underground commercial building;determine the external fluid domain size and weather according to the specifications and literature Setting of experimental environment such as parameters,heat source parameters and maintenance component temperature;proposes a design strategy of using single and combined atriums for hot pressure ventilation and using air guide systems and sunken courtyards for wind pressure ventilation,and refines single and combined atriums And the design variables of the air guide system and the sunken courtyard;use Ansys Workbench as the carrier and use the controlled variable method to conduct 24 sets of simulation experiments on the relevant design variables,and use the average wind speed,air age,and temperature of the negative one and two floors as evaluation indicators,using Excel Comparing and analyzing the simulation results with SPSS,qualitatively and quantitatively,the relationship between relevant design variables and ventilation effect is obtained,the design strategy and value range of each variable are determined,and the variable value of the preliminary design of the building is predicted.According to the results of comparative analysis and regression analysis,the following conclusions are mainly obtained: In terms of the design of hot pressure ventilation,(1)For the single atrium,increase the proportion of the top opening area,the atrium protrudes from the ground on the windward side opening,and the inner side of the closed atrium has an interface.It is beneficial to improve the ventilation effect of the atrium;(2)The ventilation effect of the combined atrium with an atrium on the windward side as an inlet and an atrium on the leeward side as an outlet is better than that of a single atrium.Increasing the distance between the two atriums,increasing the area ratio of the entrance and exit atrium,increasing the height difference between the exit and the entrance,and the closure of the atrium interface where the windward side of the entrance is perpendicular to the exit airflow is beneficial to enhance the effect of natural ventilation.In terms of wind pressure ventilation design,(1)For the wind guide system,increasing the height of the wind deflector,setting the inlet and outlet skylights axisymmetrically,increasing the width of the skylight,increasing the number of skylights on the back of the wind deflector,and continuously arranging the air guiding system is beneficial to improve ventilation.Effect;(2)For the sunken courtyard,opening on the windward side and the leeward side at the same time,increasing the area ratio,and reasonably increasing the sinking depth are beneficial to improve the ventilation effect.Through simulation experiments and analysis,this thesis reveals the relationship between the design variables and ventilation effects of the single and combined atrium and the air guiding system and the sunken courtyard.The qualitative and quantitative combination of the single and the combination determines the atrium and the air guiding system and the sunken courtyard.The variable design strategy and value range are expected to provide reference ideas and design strategies for the natural ventilation design application of underground commercial buildings.