Alternative monolithic/composite carbons for adsorption generators and simulation for optimal performance
Alternative monolithic/composite carbons for adsorption generators and simulation for optimal performance
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DOI：
10.1016/j.applthermaleng.2017.07.177
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发表时间：
2017-11
影响因子：
6.4
通讯作者：
Angeles M. Rivero-Pacho;R. E. Critoph;S. Metcalf
中科院分区：
文献类型：
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作者：
Angeles M. Rivero-Pacho;R. E. Critoph;S. Metcalf
本文介绍了三种类型的具有增强热性能的碳复合材料的开发和热性能研究，以及沿着对沃里克大学目前用于开发碳-氨热泵的壳管式发生器的几何形状的优化。硅烷粘合剂和膨胀天然石墨（ENG）作为增强其热性能的一种方式，以便在制冷或加热系统中更有效地发挥作用。采用Anter和HyperFlash热导仪测量了样品的热性能，结果表明ENG显著提高了样品的热导率（最高可达3.4 W/（mK）），但降低了碳密度（450 kg/m3），并增加了系统的热质量。木质素粘合剂样品显示出较低的热导率（0.3W/（mK）），但较高的碳密度（750 kg/m3），这提高了机器的性能。还获得了样品在宽的工作温度范围（25-200 °C）下的热导率。沃里克的燃气热泵的当前开发使用壳管式吸附发生器，其具有超过1000根直径为1.2 mm、间距为3 mm的水管。这种几何形状是没有优化和动态模拟程序已被写入，以确定有多远的最佳设计，也是否替代设计提供的优势。结果表明，壳和管是接近最佳的类型，但翅片管的设计可能会提供改进。
This paper presents the development and thermal properties study of three types of carbon composites with enhanced thermal properties along with the optimisation of the geometry of the shell and tube generators currently used at the University of Warwick for the development of carbon-ammonia heat pumps.The three carbon composites developed use lignin binder, silanes binder and Expanded Natural Graphite (ENG) as a way of enhancing their thermal properties in order to perform more efficiently in a refrigeration or heating system. Two techniques were used in order to obtain the thermal properties: Anter and HyperFlash thermal conductivity instruments.Results show that ENG increases drastically the thermal conductivity of the samples (up to 3.4 W/(mK)) but reduces the carbon density (450 kg/m3) and increases the thermal mass of the system. Lignin binder samples show lower thermal conductivities (0.3 W/(mK)) but higher carbon densities (750 kg/m3) which increases the performance of the machine. Thermal conductivities of samples were also obtained for a wide range of working temperatures (25–200 °C).The current development of gas fired heat pumps at Warwick uses shell and tube adsorption generators with over 1000 water tubes of 1.2 mm diameter on a 3 mm pitch. This geometry is not optimised and a dynamic simulation program has been written to determine how far from optimal the design is and also whether alternative designs offer advantages.The results presented show that the shell and tube is close to optimal for its type but that finned tube designs might offer improvements.