轻型竹木复合墙体的热工性能试验研究

为研究轻型竹墙的热工性能，促进推广此类新型轻质墙材在节能建筑中的应用，设计并制作了2片轻型竹墙、1片轻型木墙以及1片轻型竹木复合墙，并进行了墙体的防护热箱试验，实测获取了墙体的热阻和传热系数。结合已有文献中轻钢龙骨墙体的热工性能的试验研究结果，对轻型竹墙、轻型木墙以及竹木复合墙体等的热工性能进行了比较研究。根据ISO 6946:2007的平均传热系数计算方法对轻型竹墙、轻型木墙以及轻型竹木复合墙体的稳态传热性能进行了计算和有限元分析，验证了有限元分析的可行性。基于有限元模型分别以材料的导热系数、龙骨间距、龙骨厚度及墙内钉间距为参数对3种轻型竹木墙体的热工性能进行了模拟分析。结果表明：轻钢龙骨墙体的传热系数最大，轻型竹墙与木墙的传热系数相近，说明以竹代木的设计理念是可行的；龙骨材料的导热系数垂直积层方向变化对墙体的热工性能影响较大；增加龙骨间距可适当减小墙体的传热系数，而增大龙骨厚度则可大幅减小墙体的传热系数；墙体热工性能受墙内钉间距影响较小，钉间距超过150mm时可忽略其影响。

Experimental study on thermal performance of lightweight frame bamboo and wood walls

To study the thermal insulation performance of lightweight bamboo walls and promote the application of bamboo as a new material in energy saving construction, four lightweight frame walls representing one wood-based wall, one bamboo-wood-based wall and two full bamboo-based walls were studied by using guard hot box testing apparatus to obtain the thermal resistance and thermal transmittance. The thermal transmittance of the lightweight bamboo wall, the lightweight wood wall and lightweight bamboo-wood composite wall were compared with the experimental results including those in literature. The ISO 6946:2007 and finite element methods were used to analyze the thermal insulation performance of the lightweight walls and the reliability of the finite element simulation method was verified. The influences of anisotropic thermal conductivity, framing factor, framing thickness and nail spacing on thermal performance of lightweight bamboo wall were numerically simulated by finite element model. The results show that the thermal transmittance of lightweight steel wall is the largest, while the thermal insulation performance of lightweight frame bamboo and wood walls are similar allowing for the feasible substitution of wood by bamboo in construction. In particular, the thermal conductivity of frame material on laminated direction has certain effect on thermal insulation performance of lightweight bamboo wall as expected. Enlarging the spacing of the frame studs decreases the thermal transmittance, whereas increasing the framing thickness can greatly reduce the thermal transmittance. The thermal insulation performance of lightweight frame bamboo and wood walls are slightly affected by nail spacing and their effect can be ignored when the nail spacing is more than 150mm.