The abundance of straw in Quebec makes this material an interesting insulation option to reduce the energy consumption of buildings. At the same time, studies indicate that straw bales’ outstanding hygrothermal performance can provide a comfortable living experience for the occupants. However, due to the slightly higher thermal conductivity of straw bales insulation compared to common insulation materials, the walls are found to be 30–90% thicker, which can lead to moisture-related problems especially under a humid and cold outdoor climate. Therefore, a split-insulation wall structure was used in this study to reduce the wall thickness by combining straw bales with expanded polystyrene (EPS) exterior insulation. Results show that straw bale walls generally have higher thermal inertia and better moisture buffer capacity compared to the reference wall using glass fiber insulation. The hygrothermal profiles show that the sheathing-insulation interface is the position having the highest relative humidity in the walls. The biohygrothermal model also suggests that under Quebec’s climate, the mould grow risk in a straw bales wall with two inches EPS exterior insulation is within acceptable limits.

中文翻译：

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寒冷潮湿气候下秸秆分体保温墙组件的湿热性能

魁北克省丰富的秸秆使这种材料成为减少建筑物能源消耗的有趣的隔热选择。同时，研究表明，秸秆捆优异的湿热性能可以为居住者提供舒适的居住体验。然而，由于与普通保温材料相比，稻草包保温材料的导热系数略高，因此墙体厚度增加了 30-90%，这可能会导致与潮湿相关的问题，尤其是在潮湿和寒冷的室外气候下。因此，本研究采用分体式保温墙结构，通过将稻草捆与发泡聚苯乙烯（EPS）外保温相结合来减少墙体厚度。结果表明，与使用玻璃纤维隔热材料的参考墙相比，稻草捆墙通常具有更高的热惯性和更好的水分缓冲能力。湿热曲线显示护套-保温界面是墙体内相对湿度最高的位置。生物湿热模型还表明，在魁北克的气候下，具有两英寸 EPS 外保温材料的稻草捆墙的霉菌生长风险在可接受的限度内。