This study proposes a method for fast estimation of the hydric properties, including liquid and vapor diffusivities, of three distinct materials: a conventional biosourced insulating material (hemp concrete) and two innovative hybrid composites (hemp concrete with capric acid and hemp concrete with lauric acid). To estimate these parameters, an approach based on an inverse method has been developed. It involves minimizing the quadratic difference between numerical and experimental values of relative humidity, using the Nelder-Mead algorithm by assuming an exponential evolution of the liquid and vapor diffusivities. An unsteady-state experiment has been conducted in a climatic chamber during 18 days to provide experimental data for parameters’ estimation. The obtained maximum root mean square error (RMSE) for all the samples is 4.4% that is a satisfactory approximation given the model assumptions and the experimental uncertainties (±2%). The estimated parameters allow calculating all investigated materials’ liquid and vapor diffusivities. The validation of the approach is achieved by comparing its results with those from the existing literature.

中文翻译：

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估算常规和相变材料大麻混凝土汽液扩散系数的反演方法

本研究提出了一种快速估计三种不同材料的氢特性（包括液体和蒸气扩散率）的方法：传统的生物来源绝缘材料（大麻混凝土）和两种创新的混合复合材料（含癸酸的大麻混凝土和含月桂酸的大麻混凝土） ）。为了估计这些参数，开发了一种基于逆向方法的方法。它涉及通过假设液体和蒸汽扩散率呈指数演化，使用 Nelder-Mead 算法来最小化相对湿度的数值和实验值之间的二次差。在气候室中进行了为期18天的非稳态实验，为参数估计提供实验数据。所有样本获得的最大均方根误差 (RMSE) 为 4.4%，考虑到模型假设和实验不确定性 (±2%)，这是一个令人满意的近似值。估计的参数允许计算所有研究材料的液体和蒸汽扩散率。通过将其结果与现有文献的结果进行比较来验证该方法。