Study On The Influence Of Complex Underlying Surfaces And The Performance Of The Heat Moisture In The Building Natural Ventilation

Natural ventilation has advantages over mechanical ventilation in many aspects such as reducing building energy consumption and improving indoor thermal environment, air quality. However, the influencing factors of natural ventilation are complicated. Therefore, fully understand and utilize natural ventilation is necessary to achieve sustainable developments and to build a resource-saving and environment-friendly society.How to determine the outdoor dry-bulb temperature is crucial for designing and calculating natural ventilation. This thesis improves the CTTC model,and makes the calculation of outdoor temperature in urban natural ventilation more accurate. By analyzing the influence of calculating parameters, that is the distances between buildings, building's relative height and greening rate on the urban environment and temperature, we draw the following conclusions: the temperature of underlying surface declines as the relative height of buildings been greater, the maximum decreasing amplitude can be 1℃. Especially, the cooling effect is best when the greening rate is 35%. At the mean time, we get the parameters'distribution rules such as the outdoor ambient temperature, humidity and others under the different architectural landscape layout through site measurement.This paper chooses outdoor atmosphere - vegetation or water body- the ground and the indoor environment as the objective. We create a mathematical model by coupling indoor and outdoor environments from multi-sites. Furthermore, numerical simulation method is used to study the laws about how the vegetation, water and complex underlying surface affect on the heat and moisture of buildings natural ventilation.It is studied that the influence of the vegetation on the natural ventilation in buildings. A complete simulation algorithm of how the vegetation effect on the heat and moisture characteristics of the natural ventilation is created. By changing the height of vegetation, the distance between the vegetations and the buildings as well as the width of vegetation, the empirical formula of the engineering use are concluded. It is shown that indoor ventilation slow down, as the distance between the forest and buildings and the width of forest areas increasing. The indoor temperature drops as well, and the maximum decreasing amplitude is 1.4℃. The frequency of indoor ventilation tends to be constant, when the ratio of the distance between the forest and buildings to the building height is 75%. The frequency of indoor ventilation reaches the lowest point, when the ratio of the forest height to the building height is 50%.It is studied that the influence of the indoor surfaces on the heat and moisture'properties of the natural ventilation in buildings. The thesis not only present the concept of surface effect by fully considering those factors that the surface can transfer heat and moisture but also reconstructs the building numerical model of natural ventilation, which enriches the contents of the numerical calculation of natural ventilation. By combining simulation and on-site measurement on the natural ventilation of a factory, we conclude the following results: when the outside environment is wind-free, the former one can reduce the air temperature by 1.3-1.5℃with the rage 2m of the near-surface comparing plant on the ground by using the heat-absorbing materials with a good performance with the one with the insulation materials. At the mean time, the pressure inside the plant also reduces 0.2Pa and the rate of windshield flowing into the air velocity increases. The maximum wind speed is 1.5m/s that fully reflected the surface effect.It is studied that the influence of the body of water on the heat and moisture'properties of the natural ventilation in buildings. We establish the mathematical model and corresponding algorithms about the affect of a body of water on the heat and moisture of the natural ventilation in buildings during the process of describing the evaporation of water, using the fitting formula proposed by meteorological research literature to calculate the balance temperature of water body and corresponding evaporation by taking into account the heat and mass exchange of water and air. This formula can help us to calculate the evaporation exactly. Besides, this paper makes research on those rules of how the indoor relative humidity is affected by different temperature, humidity of free stream, width of water body and the distance between water body and the buildings, and we analyze the correlation of influence factors. The results show that: water body has more significant affect on the building indoor humidity than the indoor temperature. The larger the area of water body is, the greater effect it has. In the range from 10 meters to 15 meters, the water body has a significant affection on the indoor humidity.