Study On Dehumidification And Anti-condensation Methods Of Underground Garage In North China

In the environment of high temperature and high humidity,it is very common to have condensation problems on the walls of underground garages in North China due to humidity.When the wall surface condensation phenomenon is serious,on the one hand,it will accelerate the carbonization of the main component of the wall,reinforced concrete,on the other hand,it will accelerate the alkali-aggregate reaction.Rarely,it can cause problems such as peeling off the wall,water seepage on the wall,and mildew.More importantly,it affects the durability of the wall structure and causes irreversible damage to the garage itself.Therefore,it is of great practical significance to solve the problem of condensation on the wall of the garage.Firstly,the thesis conducted a detailed study on the wall dew condensation mechanism and ventilation and dehumidification principles,and analyzed the relationship between air parameters and dew point temperature.The ground temperature in Beijing in the studied area was calculated and compare d with the local meteorological parameters.The time range during which condensation may occur was determined,and the condensation area and amount of condensation on the walls of the garage were estimated.Secondly,taking a typical underground garage as the research object,the source of the wet load and the main influencing factors are analyzed in detail,and the wet load is calculated and reflected in the simulation.The Fluent software is used to study the most unfavorable conditions in summer and winter conditions,and verify the correctness of the theoretical calculations based on the simulation results.Then,the best calculation method for the ventilation of the garage is determined,the temperature and humidity in the summer garage are regulated b y mechanical ventilation,and the influence of different air supply speeds and relative humidity on wall condensation is studied.In order to prevent the occurrence of condensation on the wall,the critical value of the summer air supply parameter is obtai ned.The mechanical ventilation in the garage under rainfall conditions was simulated,and it was found that the condensation problem could not be completely solved.Finally,the anti-condensation theory of hot air sent by attached jet is studied.On the basis of comprehensive ventilation,the attached jet air supply method was introduced,the air volume was redistributed,and the location,size and quantity of attached jet air outlets were designed,and the optimal air supply method,air temperature and distance between the air outlets and the wall surface were obtained.The results show that when the supply air temperature is 32℃,the relative humidity is 35%,and the air outlet is 10 cm away from the wall,the temperature and humidity design requirements in the garage can be met,and the wall temperature can be raised above the dew point temperature,which provides a reference for dehumidification and anti-condensation in the garage.