Analysis of physical uncertainties in computer simulations of residential buildings

Abstract The aim of this paper is to analyse physical uncertainties in a computer simulation of a residential building and the implications for its thermal performance. The simulation experiment was performed using the Monte Carlo method, involving the thermal and physical properties of materials. The sensitivity of the variables was also analysed using regression and correlation coefficients. The degree-hours of discomfort criterion for heating and cooling for the climate of Florianópolis-SC were considered, according to adaptive thermal comfort limits. The results showed that uncertainties in degree-hours are high, i.e., 32% for cooling discomfort and 53% for heating discomfort. The uncertainty is largely due to the average monthly temperature of the ground. Other variables, such as the solar absorptance of the roof and the specific heat of the mortar of the walls had a relevant impact on heat discomfort. The density of the mortar and the specific heat of the brickwork walls affected the cooling discomfort. These variables need proper accuracy, either through more reliable databases and/or through field or laboratory measurements.

摘要 本研究旨在分析某住宅建筑计算机模拟中的物理不确定性及其对建筑热性能的影响。本次模拟实验采用蒙特卡洛方法（Monte Carlo method），围绕材料的热物理属性展开。同时通过回归分析与相关系数法，对各变量的敏感性进行了分析。研究参考自适应热舒适限值（adaptive thermal comfort limits），采用适配弗洛里亚诺波利斯-圣卡塔琳娜州（Florianópolis-SC）气候的采暖与制冷不舒适度时数（degree-hours of discomfort）标准。结果表明，不舒适度时数的不确定性水平较高：制冷不舒适工况下不确定性达32%，采暖不舒适工况下则为53%。该不确定性主要源于地面月平均温度。其余变量，如屋面太阳吸收率（solar absorptance）与墙体灰浆（mortar）的比热容（specific heat），对采暖不舒适度存在显著影响；而墙体灰浆的密度与砖砌墙体（brickwork walls）的比热容则会影响制冷不舒适度。针对上述变量，需通过更可靠的数据库、现场实测或实验室检测等方式保障其精度要求。