Optimization Research of Insulating Layer Thickness for Rural Residence’s Exterior Wall in Northeast Severe Cold Regions Based on Life Cycle Cost

As one of the essential components of rural residence’s envelope in severe cold regions, external wall’s heat transfer consumption accounts for about 40% of total heat consumption. Thermal insulation technology for exterior wall is one important method to improve building thermal performance. Meanwhile, the increasing of insulating layer thickness also raises the construction cost. It is necessary to determine the optimal thickness of external insulating layer from the perspective of life cycle cost. This paper, selecting the composite wall structure as research object and taking life cycle cost of external wall as evaluation index, establishes the GenOpt–EnergyPlus optimization platform by coupling EnergyPlus and GenOpt software to carry out the optimization. In the analysis, three types of insulation materials were selected to analysis. Considering that the length of life cycle may affect the effective utilization rate of operation and construction cost, three types of life cycle span are set, including 10, 20, and 30 years. Through the analysis, the optimal insulating layer thickness and changing rule of external wall under different conditions were discussed, which provides a basis for the selection of insulating layer’s material and thickness.