Study On The Influence Of Thermo-Hydro Stress Coupling On External Insulation Performance Of Passive House

Because of its important role in society and people's livelihood,the construction industry has brought about the vigorous development of the urban economy from various aspects in the past decades.However,in recent years,the fast-developing construction and economy also gradually exposed the shortcomings:the constructions and demolitions have consumed vast social energy,resource,which changed green mountains and rivers to tall buildings.The rapid urbanization made the city environment run counter to the concept of sustainable development.The search for solutions of high building energy consumption,such as green energy-saving buildings and ultra-low energy consumption buildings,has become a key research direction of domestic and foreign building experts and scholars and has also become an industry technology model to guide social development.The exterior insulation system adopted by passive ultra-low energy buildings has quite a high energy-saving rate.However,because the exterior insulation is located in the outer layer of building bodies,it has to bear considerable environmental test in the operation.To some extent,long-term repeated changes in temperature and humidity will cause damages to the external wall insulation system.This situation can be widely seen in the construction using the polystyrene board-thin plastering external insulation system in China.As passive buildings have been introduced into China for only several years,there is still no exterior insulation system falling off accident at present.However,considering the complex structure of the passive building wall and the high thermal indicators of the external insulation system,the overall thermal performance of the building will be affected even if there's subtle damage of a bonding surface and a wall component causing by the internal stress.Therefore,it is of high value to study the internal temperature and humidity environment of the external wall insulation system of passive ultra-low energy consumption buildings and the effect of thermo-hydro stress on its performance.Based on the research status at home and abroad,this thesis summarizes and analyzes the relevant research results of hot and humid climate areas.Tuhrough participating in the construction and monitoring of the passive building sensors in Shandong Tianzhu University,this study uses the monitoring data to carry out the numerical model of the wall of the external insulation system of the passive building.Then,this work explores the influence of the thermo-hydro stress coupling on the external insulation performance of the passive house.The innovation points are as follows:First,this thesis clarified the variation law of thermo-hydro stress coupling on external insulation of the passive house,under a high humidity environment,proposing the thermo-hydro coupling stress-strain relationship applicable to passive buildings.Based on the measured temperature and humidity monitoring data of the engineering practice project,it is concluded that there was a high humidity condition inside the external wall insulation system of the passive building at the initial stage of operation.Second,the numerical model of the double-layer staggered external insulation wall was established and the measured data were used to conduct finite element simulation to clarify the internal stress-strain relationship of the external insulation system of the passive building under a high humidity environment.According to the simulation results,sensors were arranged in a larger strain position to carry out weather ability tests.Then,the thesis presented the attenuation law of the heat transfer coefficient of passive exterior insulation system under the action of thermo-hydro coupling stress and proposed the correction coefficients.Finally,based on the results of the numerical simulation and the weather ability test,the countermeasures for the influence of thermo-hydro stress coupling on the performance of passive exterior insulation system were discussed from three aspects of exterior wall construction,building material selection,and construction method.