Optimization analysis of thermal insulation layer attributes of building envelope exterior wall based on DeST and life cycle economic evaluation

Based on the importance of building energy saving, a college building in Chengdu is selected to analyze the effect of material type and thickness of thermal insulation layer of the exterior wall on building energy consumption by using DeST energy simulation software, and through the life cycle cost analysis model to study the economic thickness value and unit cost of different insulation materials. The results show that the effect of adding insulation materials on the building envelope has less effect on the cumulative annual cooling load, but the impact of cumulative annual heat load is greater, compared with no insulation material, it can save 21.52% heat load, 3.78% total load, and 25.34% total cost per unit area. Meanwhile, this change trend between the insulation thickness and total cost shows an anti-parabolic relationship, in which there is an optimal economic thickness, but different insulation materials also have different economic thickness. Considering the cost, polystyrene is preferred as insulation material in several common insulation materials with an economic thickness of 35mm and a total cost of 76.28 RMB/m(2). Based on this, the data and conclusions presented in this paper can provide some reference for building energy saving and existing building renovation in Chengdu.