Study On The External Wall Insulation System In Hot Summer And Cold Winter Area

With the rapid development of our country’s economy, the gradual expansion ofthe whole country’s urbanization scale and people’s increasing demand of livingenvironment amenity are all at the cost of consumption of large amounts of energy.Building energy efficiency is one of the most important part of our country’s energysaving and emission reduction project. The insulation of the external wall canimprove the thermal insulation properties of the buildings’ envelop and decrease thebuildings’ energy consumption. According to the climate characteristics and people’senergy usage habits in the hot summer and cold winter area, this paper aims toanalyze the status of energy efficiency of residential building and focus on thesuitability of various technologies of external thermal insulation; use the thermalcalculation method to find out the external thermal insulation system which can meetthe requirements of building energy efficiency specification, for the different commonresidential building; compare the economies of different insulation systems whichmeet the specification and find out the optimum insulation system; solve theeconomical insulation thickness using life cycle cost method. All in all, based on thefacts in the hot summer and cold winter area, this paper is aimed at researching theappropriate external wall insulation system of different buildings. Main task includes:（1）Analyze the commonly-used domestic external wall insulation materialsaccording to the properties of thermal insulation materials. Analyze our country’spolicies and regulations on the fire prevention of external wall insulation materialsaccording to some buildings’ fire problems.（2）Analyze the application progress of wall energy saving technology andthermal insulation at home and abroad. Compare the advantages, disadvantages andpracticability of several external wall insulation system, and at the same time simulatethe heat transfer process of different insulation systems with finite element analysissoftware ANSYS.（3）Applicability research of different buildings under different insulationsystems. Choose different wall material and appropriate thermal insulation materials,do thermal calculation for building palisade structure, analyze different structural forms’ different insulation system in conformity with the specification requirementswhen structural forms are within corresponding thermal proportion range so thatdesigner can choose the external wall insulation system and thermal insulationthickness quickly and reasonably.（4）Combining with specific engineering example, implement different wallthermal insulation designs, do simulated calculation of energy consumption withbuilding energy efficiency design analysis software PBECA, check whether it is inaccordance with civil building energy-saving design specification, then analyze thecost and make comprehensive assessment of different energy saving projects.（5）Adopt life cycle cost method to make optimization calculation of insulationlayer thickness corresponded to different exterior thermal insulation materials, andanalyze economic payback period corresponded to different thermal insulationtechnology.The study result shows that when heat transfer coefficient in the major body ofexternal wall is equal, the heat preservation effect of external thermal insulationsystems in hot summer and cold winter area is in the following decreasing order:external thermal insulation, external thermal self-insulation of thermal bridge, internalthermal insulation, external thermal self-insulation. However, the thermal bridgeeffects of external thermal self-insulation and internal thermal insulation system areobvious. External thermal self-insulation system of thermal bridge not only canachieve the same thermal insulation effect with external thermal insulation system,but also can avoid the disadvantages of external and internal thermal insulationsystems. Therefore, it should be widely spread and used in hot summer and coldwinter zone. Considering that specification requires heat transfer coefficient limitindicator, villa should adopt external thermal insulation system as its heat transfercoefficient limit is smaller. The frame structure of high-rise building can adoptexternal thermal self-insulation system of thermal bridge or external thermalinsulation system. Both can be satisfied. But the previous system shows obviouseconomic advantages. As shear-wall and Frame-shear structure take up a largeproportion of the wall area, the thermal bridge place need thicker thermal insulatinglayer if thermal self-insulation system of thermal bridge is adopted. While adoptingexternal thermal insulation system, thermal insulation layer thickness of30mm can meet specification requirements. Therefore, external thermal insulation system isrecommended to use. As to the residential building adopting external thermalinsulation system, the author uses the life cycle cost analysis theory and has got theoptimum thickness and economic payback period of thermal insulation layer of thewall. Except the payback period of aerated concrete block wall is about8years, otherkinds of walls have better economic benefits with a cost-recovering period within twoto five years.