Institute of Carbon Technology, Jeonju University, 303 Cheonjam-ro, Wansan-gu, Jeonju-si, Jeollabuk-do 55069, Korea.
Carbon Composite Energy Nanomaterials Research Center, Woosuk University, Wanju, Chonbuk 55338, Korea.
Molecules. 2020 Jul 19;25(14):3280. doi: 10.3390/molecules25143280.
This study researches the effect of phase change materials (PCMs) containing carbonized rice husks (CRHs) in wood plastic composites (WPCs) as roof finishing materials on roof-surface and indoor temperatures. A cool roof miniature model was prepared, and measurements were taken using three fixed temperatures of 30 to 32 °C, 35 to 37 °C, and 40 to 42 °C. Sodium sulfate decahydrate (NaSO·10HO) and paraffin wax were selected as the PCMs. CRHs were used as additives to improve the thermal conductivities of the PCMs. At lower fixed temperatures such as 30 to 32 °C and 35 to 37 °C, the rates of increase of the surface temperatures of roofs containing CRHs with NaSO·10HO, and paraffin wax, were observed to gradually decrease compared to those of the roofs without PCMs. The indoor temperatures for the above-mentioned PCMs containing CRHs were maintained to be lower than those of the indoors without PCMs. Additionally, as the CRH content in the PCM increased, the rates of increase of the roof-surface and indoor temperatures decreased due to a faster roof heat absorption by PCMs through the improved thermal conductivity of CRHs. However, under higher artificial temperatures such as 40 to 42 °C, NaSO·10HO with CRHs exhibited no effect due to being out of latent heat range of NaSO·HO. For paraffin wax, as CRH content increased, their roof- surface and indoor temperatures decreased. Especially, the surface temperature of the roof containing paraffin contained 5 wt.% CRHs reduced by 11 °C, and its indoor temperature dropped to 26.4 °C. The thermal conductivity of PCM was enhanced by the addition of CRHs. A suitable PCM selection in each location can result in the reduction of the roof-surface and indoor temperatures.
本研究旨在探讨作为屋顶装饰材料的含碳化稻壳（CRH）的相变材料（PCM）对屋顶表面和室内温度的影响。制作了一个小型凉爽屋顶模型，并使用三个固定温度（30 至 32°C、35 至 37°C 和 40 至 42°C）进行了测量。选择硫酸钠十水合物（NaSO·10HO）和石蜡作为 PCM。CRH 被用作添加剂，以提高 PCM 的热导率。在较低的固定温度（如 30 至 32°C 和 35 至 37°C）下，与不含 PCM 的屋顶相比，发现含 CRH 的 NaSO·10HO 和石蜡 PCM 的屋顶表面温度增长率逐渐降低。上述含 CRH 的 PCM 可以将室内温度保持在比无 PCM 的室内温度低。此外，随着 PCM 中 CRH 含量的增加，由于 CRH 提高了 PCM 的热导率，屋顶吸收热量的速度加快，因此屋顶表面和室内温度的增长率降低。然而，在更高的人工温度（如 40 至 42°C）下，由于 NaSO·10HO 处于其潜热范围之外，含 CRH 的 NaSO·10HO 没有效果。对于石蜡，随着 CRH 含量的增加，它们的屋顶表面和室内温度降低。特别是，含 5wt.%CRH 的石蜡屋顶表面温度降低了 11°C，其室内温度降至 26.4°C。PCM 的热导率通过添加 CRH 得到了提高。在每个地点选择合适的 PCM 可以降低屋顶表面和室内温度。
