Research On Thermal Performance And Thermal Bridge Effect Of Fabricated Hollow Shear Walls Made From Thermal Insulation Concrete

In view of the high energy consumption of buildings in our country nowadays,to overcome the quality and safety problems of traditional wall thermal insulation and to response to the call of promoting the development of fabricated buildings,applying hollow shear walls made from glazed hollow beads thermal insulation concrete(GHBTIC)into fabricated wall systems is proposed.Fabricated hollow shear walls made from GHBTIC combine the material of GHBTIC and the structure form of hollow shear wall together,it conforms to the trend of building industrialization as well as integrates bearing capacity and thermal insulation goal of wall together,so the research on it has magnificent significance.In this paper,thermal performance and the thermal bridge effect of cast-in-situ concrete joints and regions nearby on fabricated hollow shear wall is studied,then thermal bridge external insulation structure is put forward.This research provides a reference for the practical application of the wall system.Specific studies are as follows:1.The heat transfer experiment on the model of thermal bridge and regions nearby of the fabricated hollow shear wall as well as steady thermal analysis by finite element analysis software ANSYS is conducted.It is found that The simulation results are in good agreement with the experimental results.when the hollow in the fabricated hollow shear wall is filled with PU thermal insulation foam,the heat transfer coefficient of the wall can be reduced by 32.8%.The external facet of thermal bridge insulated by 50 mm thick XPS on the basis of hollow filling by PU thermal insulation foam can reduce the heat transfer coefficient by 16.2-18.7% additionally.After hollow filling and thermal bridge external insulation treatment,the experimental values of heat transfer coefficient of the thermal bridge and region nearby on the wall model FHSW-B,FHSW-D are 0.954 W/m~2×K and 0.957 W/m~2×K,which can satisfy the requirement of building energy efficiency value 65% in the Design standard for energy efficiency of residential buildings in hot summer and cold winter zone(JGJ134-2010).The hollow filling of the wall will effectively shrink the influenced scope of thermal bridge,the thermal bridge external insulation treatment will basically eliminate the influenced scope of thermal bridge,thus these are effectively measurement to reduce thermal bridge effect.Furthermore,the hollow filling of the wall and the thermal bridge external insulation treatment will lead to larger temperature gradient,which will enhance the thermal insulation and heat resistance capacity of the wall.By comparison,the simulation value of heat transfer coefficient is almost the same as the experimental value;while the theoretical value has big difference with the simulation and experimental value.2.The thermal bridge external insulation structure of fabricated hollow shear wall is optimized by ANSYS.Conduct the heat–stress coupled simulation on the model of thermal bridge with external insulation structures in different thicknesses and widths and then contrastively analyse the result.It is found that the thicker and wider the thermal insulation structure are,the smaller thermal bridge influenced scope of the wall and the lower heat transfer coefficient are.The different sizes of thermal bridge external structure have little influences on the stress and displacements of the wall.The result can be got through simulation analysis that when the cast-in-situ concrete joint width is 200 mm and 250 mm,the optimized thermal bridge insulation structure sizes are 30mm×300mm and 30mm×350mm.The heat transfer coefficient of walls are 0.874W/m~2×K and 0.902 W/m~2×K,which can satisfy the requirement of building energy efficiency value 65% in hot summer and cold winter zone.3.The heat-stress coupled transient analysis on the model of thermal bridge and regions nearby of the fabricated hollow shear wall is conducted on basis of the optimized thermal bridge external insulation structure.It is founded that the temperature damping multiple between the inner and outside facet of the wall is 77.78,the temperature delay time of it is 12 h.When the average temperature variation of outside facet of the wall is 6.03°C,the average temperature variation of inner facet of the wall is 0.09°C and the inner facet of the wall will not dew.Thus,this fabricated hollow shear wall enable the good indoor thermal and humid environments,which can satisfy the demand of indoor residential comfortableness.When the indoor heating temperature range from 18°C to 26°C in winter,it will not condense in the wall.The wall has good ability to resistant vapor invasion,so it has quite good dampproof performance.