Research On Heat Transfer Performance Of Assembled Concrete Air Sandwich Wall Panel

Building energy conservation is an important technical field faced by the construction industry in this century.Assembled concrete air-sandwich insulation exterior wall panel has become an important direction of building energy conservation technology development at this stage because of its many advantages.In recent years,many universities and research institutes at home and abroad have carried out a lot of research work on fabricated concrete air-interlayer thermal insulation exterior wall panels.The research results are fruitful.However,nowadays,with the increasing demand for building energy saving,a lot of scientific research work is still needed to support the development of fabricated concrete air-interlayer thermal insulation exterior wall panels.Therefore,in this paper,the heat transfer characteristics of the fabricated concrete air sandwich wallboard with standard floor are studied by theoretical analysis,numerical simulation and experimental verification.The thermal insulation composite wallboard with excellent thermal insulation performance in cold C zone was obtained.The main contents are as follows:(1)Obtain the optimum size range of the closed air layer in the assembled concrete air interlayer thermal insulation exterior wall panelsStarting from the flow and heat transfer characteristics of the air interlayer inside the fabricated concrete air interlayer insulation exterior wall panels,the heat transfer law of the air interlayer with the change of the size of the interlayer and the temperature difference between the two sides is studied by numerical simulation,and the optimal size range of the air interlayer in the wall panels is obtained.(2)A kind of fabricated concrete double-layer air sandwich insulation external wall panel is proposedBased on the recommended technical practices in national standards,the thermal insulation performance of assembled concrete sandwich thermal insulation exterior wallboard is improved by optimizing the combination of sealed air sandwich as thermal insulation material and assembled exterior wallboard.Concrete is used as organic and inorganic thermal insulation materials,such as inner and outer leaves of the wall,EPS,and the combination of single and double air interlayer as thermal insulation functional layer to complete the structural design and preparation of assembling concrete air interlayer thermal insulation external wall slab for building standard layer.The accuracy of the calculation method,process and result is verified by the thermal conductivity measurement experiment.The heat transfer coefficient of the fabricated concrete double-layer air sandwich exterior wall is only 0.225W(7)m ~2?K(8),and its thickness is80%of the typical wall in Liaoning Province.(3)Analyzing and calculating heat transfer process of assembled concrete air interlayer thermal insulation exterior wall panelThe heat transfer coefficients of ten kinds of building standard wall panels with different thickness of insulation layer are calculated by numerical calculation method,and the equation of heat transfer coefficient and thickness of insulation layer is fitted.According to the limit value of heat transfer coefficient and comfort requirement of wall panels given in Code for Thermal Design of Civil Buildings(GB50176-2016),the assembled concrete air-sandwich thermal insulation external wall panels meeting the comfort requirement of cold C zone are selected.The thermal performance indexes of two kinds of fabricated concrete air-interlayer thermal insulation exterior wall panels and typical external thermal insulation composite wall in Liaoning area are calculated.The thermal performance of fabricated concrete air-interlayer thermal insulation exterior wall panels is superior to that of typical wall in Liaoning area.(4)Simulating study on natural convection heat transfer of assembled concrete air-interlayer thermal insulation exterior wall panelTaking the standard floor of the experimental building of Liaoning University of Science and Technology as an example,this paper studies and analyses the influence of the assembled concrete air-interlayer thermal insulation composite wallboard on the indoor thermal environment and air distribution in winter,and maintains the thickness of the outer wall unchanged.Only by changing the air-interlayer in the wall from a single layer to a double-layer structure,the indoor average temperature can be raised by 0.8 C as a whole.To sum up,this paper designs a kind of assembled concrete double-layer air sandwich thermal insulation external wall board suitable for buildings in cold C area.A model for heat transfer and indoor temperature calculation of the wallboard is established.The thermal performance of the wallboard was studied and the engineering practice was carried out.In order to provide a new type of energy-saving exterior wall for people's comfortable living environment in cold C area.The paper has 48 pictures,15 tables,and 74 references.