The Influence Of Building Envelope On Building Load In Hot And Humidity Area

With the rapid development of the economy,the demand for energy is gradually increasing,and the following problems such as energy shortage and pollution are increasingly serious.The building energy consumption accounts for about 30%of the total energy consumption.The external building envelope has a great impact on the overall energy demand of the building.The building load formed by the heat and humidity flow entering the indoor through the building envelope is an important part of the building energy consumption.Therefore,it is very important to grasp the influence of the configuration of building envelope on the building load.Because most of the building materials are porous structure,not only the heat flow can pass through the wall to raise sensible heat load,but also the moisture content of the outdoor environment can raise latent heat load through the wall.So the transfer processes of moisture and heat are interacted inside the wall,especially in the hot and humid climate region Hainan of China.Besides,windows is an important part of building envelope,so the orientation of windows and the window-to-wall ratio(WWR)also have an important impact on building loads.With the decrease of window-to-wall ratio(WWR)the lighting load will gradually rise because of the demand for illumination,but with the increase of window-to-wall ratio(WWR),the increase of illumination will produce a certain risk of glare.Therefore it is necessary to calculate the distribution characteristics of building loads in hot and humid climate region in China by combining the coupled heat and moisture transfer process in walls and the influencing factors of windows.A temperature and humidity chamber sized 4m*4m*4m is established.And,the finite element method is used to calcualted the sensible load and latent load through the building wall,and the software Ecotect and Desktop Radiance is used to simulate the natural illumination of the building and then get the lighting load.Then the total load distribution of buildings in different months and year is obtained.Finally,the paper compares the energy-saving situation of addingwall insulation and sunshade in the window.The results show that The process of moisture transfer has a great influence on heat transfer,and the sensible heat load produced by the moisture flow accounts for a large proportion of the total load.And window orientation has little effect on latent load,but has a great effect on sensible load.When the window-to-wall ratio is gradually increased,the lighting load increases slowly.The optimum window-to-wall ratio exists for the total annual load with different window orientation,and all of the optimal window-to-wall ratios are around 0.3.Compared with window shading,wall insulation can reduce more energy consumption,but considering that the window accounts for a smaller area of the total building envelope,so the window has certain energy saving potential.