| As the building energy consumption is increasing in China,in this case,building energy conservation has become a top priority.Insulation measures in building external wall is an effective way to realize building energy saving,therefore,the reasonable selection and effective utilization of the building insulation materials is the key to achieve building energy efficiency.With the increase of the insulation thickness,the thermal performance of the external wall gradually increased,the corresponding total energy consumption will gradually reduce,but the use of thermal insulation materials in the initial investment will also increase,Then,from the economic point of view,there must be an optimum thickness of the insulation layer,making the total cost of building the lowest.This study is based on the theory of life cycle assessment,with building energy efficiency and economy as the criterion,by the total cost of the insulation life cycle as an indicator,to analyze and investigate the optimal insulation thickness about the four kinds of thermal insulation materials which are XPS,EPS,Rock wool and Vitrified microsphere when used in the building external wall.In this paper,we were taking a multilayer office building as the research object,and established a benchmark building model,While using the building energy simulation software that is Designbuilder,to study the building energy efficiency and economic effects in hot summer and warm winter areas,hot summer and cold winter areas,cold areas and severe cold areas when the external wall used XPS,EPS,Rock wool,Vitrified microsphere in different thickness,at the same time,combined with the life cycle assessment,obtained the optimal insulation thickness of different thermal insulation materials which were used in different climatic regions,finally,analyzed the results of the simulation.The results show that:For the same climate area,the total energy saving rate,XPS is better than EPS,Rock wool is better than Vitrified microsphere,and the organic materials are better than the inorganic materials;Building energy efficiency is closely linked to climate conditions,and enhance the external wall insulation on the cold especially in the severe cold areas,the effect is very significant,while in the hot summer and warm winter area is poor,instead,it will increase the total cost of life cycle in this area;In different climate region,with the increase of the insulation thickness,the energy saving rate gradually increases,but the increasing extent is getting smaller and smaller,tends to be gentle;Using the life cycle assessment obtained that,with the typical main material of external wall structure,the optimal thickness of XPS,EPS,Rock wool and Vitrified microsphere,in the hot summer and warm winter regions were 20mm,30mm,20mm,20mm respectively;in the hot summer and cold winter regions were 30mm,40mm,20mm,20mm respectively;in the cold regions were 60mm,80mm,60mm,70mm,respectively;in the severe cold regions were 140mm,160mm,120mm,150mm,respectively.The optimum thickness of every material is related to the material use cost and the building operation cost,cannot determined by one case,that is in different climate regions,when the building external wall choose different insulation materials,the better of the total energy saving effect,the optimal thickness of the insulation layer may be too large.At last in this paper,taking the hot summer and cold winter area as an example,and combined with the actual engineering research information in this region,conducted a comprehensive evaluation about the optimal insulation thickness of the four kinds of thermal insulation materials between the study results and the engineering applications,and provide a reference for the reasonable selection and effective utilization of the thermal insulation materials in hot summer and cold winter areas and other climatic regions,at the same time,it can also optimize parameters for the building energy-saving design and building energy-saving reconstruction. |
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