An investigation of thermal stability of carbon nanofluids for solar thermal applications
An investigation of thermal stability of carbon nanofluids for solar thermal applications
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DOI：
10.1016/j.solmat.2016.07.032
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发表时间：
2016-12-01
影响因子：
6.9
通讯作者：
Scott, Jason
中科院分区：
文献类型：
--
作者：
Mesgari, Sara;Taylor, Robert A.;Scott, Jason
碳纳米流体是具有可控的热和光学性质的工程材料。这些流体的稳定、高温操作（> 20）将使它们能够在许多重要的商业和工业应用（包括太阳能集热器中的应用）中改进并最终取代纯流体。然而，迄今为止，大部分纳米流体研究都集中在低温（< 100摄氏度）应用和测试上。对于太阳能集热器应用，碳纳米流体由于其在整个太阳光谱范围内的高吸收率而非常适合。这项研究通过进行一系列实验来确定适当的基础流体和功能化方法，以在高达250摄氏度的温度下生产稳定的碳纳米管（CNT）基纳米流体分散体，以确保其适用于工业加热应用（通常为100-250摄氏度）。不同形式的碳纳米管，包括单壁碳纳米管、双壁碳纳米管和多壁碳纳米管，经过化学官能化，在水、乙二醇和Therminol（一种合成导热油）中获得稳定的分散体。研究了化学官能化碳纳米管分散体在不同温度（20、80、100、150、200和250 ° C）下的稳定性。宽带UV-VIS-NIR光谱的结果显示，当加热到250摄氏度时，分散在Therminol中的轻度氧化的多壁碳纳米管没有团聚，突出了这种低成本的复合介质作为高温纳米流体太阳能集热器的潜在候选者。(C)2016爱思唯尔B. V.保留所有权利。
Carbon nanofluids are engineered materials with controllable thermal and optical properties. Stable, high temperature operation ( > 20) of these fluids would enable them to improve upon and eventually replace pure fluids in many important commercial and industrial applications including applications in solar thermal collectors. To date, however, much of the nanofluids research focuses on low temperature ( < 100 degrees C) applications and testing. For solar thermal collector applications, carbon nanofluids are uniquely well-suited due to their high absorptivity over the entire solar spectral range. This study pushes well beyond the 100 degrees C mark by conducting a range of experiments to identify appropriate base fluids and functionalization methods to produce stable carbon nanotube (CNT)-based nanofluid dispersions at temperatures of up to 250 degrees C to ensure their suitability for industrial heating applications (typically 100-250 degrees C). Different forms of CNTs including, single-walled carbon nanotubes, double-walled carbon nanotubes and multi-walled carbon nanotubes were chemically functionalized to obtain stable dispersions in water, glycol and Therminol (a synthetic heat-transfer oil). The stability of chemically functionalized carbon nanotube dispersions at different temperatures, 20, 80, 100, 150, 200 and 250 degrees C, was investigated. The results of broadband UV-VIS-NIR spectroscopy showed no agglomeration in mildly oxidized multi-walled carbon nanotubes dispersed in Therminol when heated to 250 degrees C, highlighting this low-cost composite medium as a potential candidate for use in high temperature nanofluid-based solar thermal collectors. (C) 2016 Elsevier B.V. All rights reserved.