The \emph{in situ} estimation of the thermal properties of existing building wall materials is a computationally expensive procedure. Its cost is highly proportional to the duration of measurements. To decrease the computational cost a methodology using a D-optimum criterion to select an optimal experiment duration is proposed. This criterion allows to accurately estimate the thermal properties of the wall using a reduced measurement plan. The methodology is applied to estimate the thermal conductivity of the three-layer wall of a historical building in France. Three different experiment sequences (one, three and seven days) and three spatial distributions of the thermal conductivity are investigated. Then using the optimal duration of observations the thermal conductivity is estimated using the hybrid optimization method. Results show a significant reduction of computational time; and reliable simulation of physical phenomena using the estimated values.

翻译：对现有建筑墙壁材料热特性的估计是一种昂贵的计算程序,其成本与测量时间长短成比例。为了降低计算成本,建议采用D-最佳标准选择最佳试验时间。这一标准可以使用减少的测量计划准确估计墙壁热特性。该方法用于估算法国历史建筑三层墙的热传导率。对热导力的三个不同的试验序列(一、三和七天)和三个空间分布进行了调查。然后利用最佳观测时间使用混合优化方法估计热导力。结果显示计算时间显著缩短;用估计值对物理现象进行可靠的模拟。