| Nowadays,with the rapid development of technology in the construction industry,China is exposed to the building energy consumption.At the present stage,porous materials are the most widely used building materials and its properties of thermal and moisture affect the overall energy consumption of buildings directly.Thus,it's imperative to improve the energy efficiency of building envelope fundamentally by studying the heat and humidity transfer of porous building materials and reducing the energy loss.In this paper,the transient coupled transfer control equation of heat and humidity in the wall is derived by the theory of fundamental transmission,Fick and Darcy's law.Then,in order to improve the feasibility and practicability of the equation in the practical application,the author improved the driving potential,simplified and substituted the equation and changed the application of enthalpy value.The software“COMSOL”is used to verify the feasibility and practicability of the derived equations by comparing the experimental data in the literature.The effects of environmental temperature and time on the wet transfer of aerated concrete were simulated and analyzed.It showed that the moisture transfer rate slowed down with the increase of time.What's more,in 5?15?,the rate of moisture transfer changed slowly and the impact of temperature is definite;in 15?30?,the moisture transfer was slightly faster and the rate was almost the same,which was almost not affected by temperature.Therefore,the temperature of the aerated concrete wall which below 15?can reduce the external moisture transfer in the dry environment effectively.When the temperature of simulation is 5?,the average water vapor transmission rate is 0.01147?10-3m/min where the relative humidity inside the sample is 5%RH.In this paper,the author used the existing equipment and the procurement of the equipment to build a one-dimensional heat and moisture transfer experiment platform to study the heat and moisture transfer in different porous building materials.The effect of climatic conditions on the heat and moisture transfer of three kinds of porous materials was measured in Hangzhou area in November,and the relevant meteorological data were collected during the experiment.The results show that the moisture permeation property of autoclaved aerated concrete and thermal mortar is better than ordinary concrete.The moisture transmission speed of autoclaved aerated concrete is 0.01661?10-3m/min.The moisture transmission speed of thermal mortar is 0.01935?10-3m/min.The moisture transmission speed of thermal mortar is better than autoclaved aerated concrete. |
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