Islam Saiful, Furuta Hiroshi
School of Systems Engineering, Kochi University of Technology, Kochi 782-8502, Japan.
Center for Nanotechnology, Research Institute, Kochi University of Technology, Kochi 782-8502, Japan.
Nanomaterials (Basel). 2024 Oct 11;14(20):1633. doi: 10.3390/nano14201633.
This study investigates the process of using multi-walled carbon nanotube (MWCNT) coatings to enhance lamp heating temperatures for solar thermal absorption applications. The primary focus is studying the effects of the self-organized honeycomb structures of CNTs formed on silicon substrates on different cell area ratios (CARs). The drop-casting process was used to develop honeycomb-structured MWCNT-coated absorbers with varying CAR values ranging from ~60% to 17%. The optical properties were investigated within the visible (400-800 nm) and near-infrared (934-1651 nm) wavelength ranges. Although fully coated MWCNT absorbers showed the lowest reflectance, honeycomb structures with a ~17% CAR achieved high-temperature absorption. These structures maintained 8.4% reflectance at 550 nm, but their infrared reflection dramatically increased to 80.5% at 1321 nm. The solar thermal performance was assessed throughout a range of irradiance intensities, from 0.04 W/cm to 0.39 W/cm. The honeycomb structure with a ~17% CAR value consistently performed better than the other structures by reaching the highest absorption temperatures (ranging from 52.5 °C to 285.5 °C) across all measured intensities. A direct correlation was observed between the reflection ratio (visible: 550 nm/infrared: 1321 nm) and the temperature absorption efficiency, where lower reflection ratios were associated with higher temperature absorption. This study highlights the significant potential for the large-scale production of cost-effective solar thermal absorbers through the application of optimized honeycomb-structured absorbers coated with MWCNTs. These contributions enhance solar energy efficiency for applications in water heating and purification, thereby promoting sustainable development.
本研究探讨了使用多壁碳纳米管（MWCNT）涂层提高灯加热温度以用于太阳能热吸收应用的过程。主要重点是研究在不同电池面积比（CAR）下，在硅基板上形成的碳纳米管自组织蜂窝结构的影响。采用滴铸工艺制备了具有不同CAR值（范围从约60%到17%）的蜂窝结构MWCNT涂层吸收器。在可见光（400 - 800 nm）和近红外（934 - 1651 nm）波长范围内研究了光学特性。尽管完全涂覆的MWCNT吸收器显示出最低的反射率，但CAR约为17%的蜂窝结构实现了高温吸收。这些结构在550 nm处保持8.4%的反射率，但在1321 nm处其红外反射率急剧增加到80.5%。在从0.04 W/cm到0.39 W/cm的一系列辐照强度范围内评估了太阳能热性能。CAR值约为17%的蜂窝结构在所有测量强度下始终表现优于其他结构，达到最高吸收温度（范围从52.5°C到285.5°C）。观察到反射率（可见光：550 nm/红外：1321 nm）与温度吸收效率之间存在直接相关性，其中较低的反射率与较高的温度吸收相关。本研究强调了通过应用涂覆有MWCNT的优化蜂窝结构吸收器大规模生产具有成本效益的太阳能热吸收器的巨大潜力。这些贡献提高了水加热和净化应用中的太阳能效率，从而促进可持续发展。
