The Analysis And Effective Blocking Of Thermal Bridge Of Shear-Wall And Floor In Hot Summer And Cold Winter Zone

Building energy efficiency has considerable significance for establishing a lowcarbon economy,energy conservation,promoting sustainable economic development in our country.Thermal bridge form is varied,wall thermal bridge,beam thermal bridge,column thermal bridge and slab thermal bridge are particular representative.In shear-wall structure,heat transmission through the thermal bridge of shear-walls and floor slabs has an important impact on energy-efficient buildings.Simulation of building energy consumption in hot summer and cold winter zone is limited to onedimensional heat transfer method,but the two-dimensional and three-dimensional heat transfer characteristics of thermal bridges of building envelope can not be emphatically ignored.In this paper,the wall heat transfer coefficient test of the conventional filling wall and the new filling wall of shear-wall structure is carried out,finite element method has been utilized to analyze the two-dimensional heat transfer characteristics of the thermal bridge of conventional filling wall,new filling wall and corresponding conventional shear-wall,new shear-wall,the thermal performance of various types of the thermal bridges can be obtained,and the effective blocking measures of the thermal bridges are proposed,the main results of this paper are as follows.(1)Based on the previous research of the ultra lightweight energy-saving wall block,lightweight gypsum plaster,lightweight self-leveling mortar and other new building materials,An optimized form of shear-wall,filling wall and floor structure,suitable for hot summer and cold winter zone is proposed.The research on wall heat transfer coefficient test of conventional form and optimized form of filling wall showed that,the practical test result consistent with the theoretical calculation,the wall heat transfer coefficient of optimized form decreased by 5.2% compared with conventional form.(2)Finite element analysis of two-dimensional steady state heat transfer of conventional form,improved form and optimized form of shear-wall structure thermal bridges is carried out.Thermal simulation shows that,for shear-wall thermal bridge,the influencing area of the thermal bridge is not affected by material of filling wall and heat insulating material of shear-wall.Optimized form can be obtained by extending the insulation material to the filling wall 280 mm.Equivalent thermal heat transfer coefficient of optimized “-”-shaped and L-shaped thermal bridge decreased by 20.3% and 18.6%,compared with conventional form.Mean heat transfer coefficient for external walls of optimized “-”-shaped and L-shaped thermal bridge decreased by 11.8% and 14.4%,compared with conventional form.Equivalent thermal heat transfer coefficient and mean heat transfer coefficient for external walls are decreased significantly by effective blocking measures,and it can effectively reduce the energy consumption of the wall.(3)Finite element analysis of two-dimensional steady state heat transfer of conventional form,improved form and optimized form of shear wall-floor slab thermal bridges and filling wall-floor slab thermal bridges is carried out.For floor slab thermal bridge,heat flux in the lower surface of the floor 730 mm are attenuated to a very weak state,whether it is the shear wall or filling wall on both sides of the floor,optimized form can be obtained by extending the insulation material to the lower surface of the floor 730 mm,optimized form of filling wall also includes that extend the insulation material of floor to the filling wall 280 mm,and the influencing area of the thermal bridge is not affected by height of the beam.Equivalent thermal heat transfer coefficient of optimized shear wall-floor slab thermal bridge and filling wall-floor slab thermal bridge decreased by 53.8% and14.4%,compared with conventional form.Mean heat transfer coefficient for external walls of optimized shear wall-floor slab thermal bridge and filling wall-floor slab thermal bridge decreased by 16.7% and 15.3%,compared with conventional form.The energy consumption of shear wall-floor slab thermal bridge and filling wall-floor slab thermal bridge is remarkably reduced.At the end,a compendious sum-up and the research expectation about the project are brought out.