民居节能建筑外墙保温层最优厚度仿真

为提高建筑外墙保温层厚度计算结果的精度,提出基于LCCA(Life Cycle Cost Analysis)的民居节能建筑外墙保温层最优厚度计算方法。根据采暖度日数、建筑物围护结构的传热阻等值计算建筑外墙热损失。利用保温层投资与采暖燃料投资相加所得值,获取单位面积建筑外墙保温层的生命周期范围内总投资。采用反应系数法与z传递函数法分析并计算围护结构非稳态逐时热流。结合外墙热损失、保温层使用寿命内费用和墙体逐时热流分析结果,计算民居节能建筑外墙保温层最优厚度。实验发现,保温层存在一个最优厚度,可以使建筑的总费用降到最低;相同保温材料,最优保温层的厚度会随着现值因子增大不断增大,随着采暖度日数增大逐渐增大,随着非保温层热阻值增大不断减小;保温材料不同,最优保温层厚度的差异体现在随着现值因子、采暖度日数增大逐渐增大,随着外墙的非保温层热阻值增大逐渐减小;保温层最优厚度计算结果与实际值拟合度高。

Optimal Thickness Simulation of Exterior Wall Insulation Layer for Residential Building

In order to improve the accuracy of calculating the thickness of thermal insulation layer of building exterior wall,a method to calculate the optimal thickness of thermal insulation layer of residential energy-saving building exterior wall based on Life Cycle Cost Analysis(LCCA)was proposed.The heat loss of building external wall was calculated by the heating degree days and the heat transfer resistance of building envelope.The total investment in the life cycle of building external wall insulation layer of per unit area was obtained by the total investment of insulation layer and heating fuel.Moreover,response factor method and z-transfer function method were used to analyze and calculate the unsteady hourly heat flow of building envelope.Based on the heat loss,the cost within service life of insulation layer and the analysis results of hourly heat flow,the optimal thickness of external wall insulation layer of residential energy-saving buildings was calculated.Simulation results show that,there is an optimal thickness of insulation layer,which can minimize the total cost of buildings.For same thermal insulation materials,the thickness of optimal insulation layer increases with the increase of present value factor,and it increases with the increase of the number of heating degree days.In addition,it also decreases with the increase of thermal resistance of non-insulation layer.If the thermal insulation materials are different,the thickness of optimal insulation layer increases with the increase of present value factor and heating degree days,it decreases with the increase of thermal resistance of the non-insulation layer of external wall.Therefore,the fitting degree between the calculation result of optimal thickness and the actual value is high.