Technic And Performance On Structuraland Energy Efficient Sandwich Walls

Under the influence of energy crisis in the world, conserving energy in manyfields attracts more attention, including energy conservation in buildings. Theenergy conservation of buildings began relatively late in China. Although in recentyears the government has increased its promotion, the development is rather slowand still has some problems. Due to defectives in building structure and imperfectfactors in the procedures, as well as the cooperation of professional research onenergy-saving buildings are not close, as a result, there is a great gap betweenstructure, hot effect and wet effect, fire prevention, durability and other aspects.Based on the National science and technology support program ‘Thermal andStructural Integration of Wall and Roof Materials and Application TechnologyResearch’(2011BAE14B05), the efficient and durable insulation composite wallprogram was established.This paper summarized the faults in traditional insulation cavity walls on thebasis of its research, then developed a new kind of walls which can combinestructure and energy-saving, from inner to outer wall respectively, the inner leafbearing wall, the poly ethylene foam insulation board, foamed concrete andself-bearing outer leaf wall. The research benefits to the heat preservation effect andmeeting the mechanics of the load effect, reducing the load of W type block, savesthe materials. Furthermore, the new tie bars promotes heat preservation effects．Thesolution to the tie bar and edge restraints reinforced superimposed in mortar layer isa new combination as well as its integration legend. A prefabricated channel beam isalso invented to effectively reduce the thermal bridge and improve wall insulationproperties.The finite element models of thermal analysis in the main place of the wall,gable wall which includes slab bridges (traditional insulation cavity walls, troughgirder) and the position of window thermal bridge were established by softwareANSYS, the conclusions are as follows. With the same thickness of the walls, theheat transfer coefficient proposed here is smaller than the traditional ones, namelyits insulation performance is well. Traditional construction needs400mm thicknessof wall to reach the goal of65%energy-saving, whereas the slot modal beams arebetter than traditional cantilever plate in heat preservation, by the new structureconstruction, just the thickness of380mm wall can meet the same target of energysaving. Steam permeability coefficient method was used for wet analysis of the wall,the conclusions are that, the water vapor will be inevitably produced in insulationcavity walls, the results still meets the thermal specification. The range of steamcondensing is also different in the thermal bridge place of slabs and the windows.The conclusion to this project is the wall with structure ability and energyintegration could attain the goal of high efficiency and energy saving. It is one ofthe best choices of the exterior walls.