基于碳纳米管的太阳能吸附制冷复合吸附剂的性能研究

发布时间：2019-06-27 12:59

【摘要】：节能、环保和可持续发展是在21世纪的三大主题。吸吸附制冷是一种环境友好型节能制冷技术，可由太阳能、废热等低温热源驱动，且制冷剂采用氨、水、甲醇等天然工质，因此被认为是21世纪传统压缩式制冷技术的主要替代技术之一。 由于吸附工质对是吸附制冷系统的核心，，在很大程度上直接决定着吸附制冷系统的性能，因此新型吸附剂的开发及其吸附性能测试尤为重要。本文首次将比表面积大且具有独特中空结构的碳纳米管引入太阳能吸附制冷领域，并与具有较大吸附量的碱土盐类化合物氯化钙进行有机复合，探讨基于碳纳米管的复合吸附剂的吸附性能及其在吸附制冷领域的应用潜力。 本文设计了一套吸附性能测试装置，利用磁致伸缩液位传感器测得的液位的变化来计算制冷剂的吸附量/脱附量，同时利用恒温油浴锅和低温恒温箱来模拟太阳能热水器产生的热水及期望获得的制冷工况。原台架利用普通球阀控制各部分的开闭，最后发现普通球阀无法满足实验所需的气密性要求，故对台架进行了重新设计和加工。改进后的台架采用真空系统专用高真空手动挡板阀，所有部件采用快卸法兰进行连接。 在新的实验台上，分别对含5%和7.5%碳纳米管的复合吸附剂的吸水性能进行了实验测试。实验结果表明，当吸附温度为50℃、蒸发温度为20℃时，含5%碳纳米管的复合吸附剂的平衡吸附量为0.20126g/g；吸附温度为80℃时，含7.5%碳纳米管的复合吸附剂的平衡吸附量为0.16486g/g，比含5%碳纳米管的复合吸附剂的平衡吸附量提高了44.6%；当吸附温度均为70℃时，含7.5%碳纳米管的复合吸附剂的平衡吸附量为0.18914g/g，比含5%碳纳米管的复合吸附剂的平衡吸附量提高了36.5%。且系统中的残留水蒸气只对初始阶段的吸附量影响大，对总吸附量影响较小，且温度越低残留蒸汽影响越小。总之，碳纳米管确实可以增大吸附量，因此在吸附制冷领域具有应用潜力。
[Abstract]:Energy conservation, environmental protection and sustainable development are the three major themes in the 21 st century. Adsorption refrigeration is an environmentally friendly energy-saving refrigeration technology, which can be driven by solar energy, waste heat and other low temperature heat sources, and the refrigerants use ammonia, water, methanol and other natural refrigerants, so it is considered to be one of the main alternative technologies of traditional compression refrigeration technology in the 21st century. Because the adsorption working fluid pair is the core of the adsorption refrigeration system, to a large extent, it directly determines the performance of the adsorption refrigeration system, so the development of new adsorbents and the test of their adsorption properties are particularly important. In this paper, carbon nanotubes with large specific surface area and unique hollow structure are introduced into the field of solar adsorption refrigeration for the first time, and organically composite with calcium chloride, a alkali soil salt compound with large adsorption capacity. The adsorption properties of the composite adsorbents based on carbon nanotubes and their application potential in the field of adsorption refrigeration are discussed. In this paper, a set of adsorption performance testing device is designed to calculate the adsorption capacity / desorption amount of refrigerants by using the change of liquid level measured by magnetostrictive liquid level sensor. At the same time, the constant temperature oil bath pot and low temperature constant temperature box are used to simulate the hot water produced by solar water heater and the expected refrigeration conditions. The original bench uses the ordinary ball valve to control the opening and closing of each part. finally, it is found that the ordinary ball valve can not meet the air tightness requirements of the experiment, so the bench has been redesigned and machined. The improved bench adopts high vacuum manual baffle valve for vacuum system, and all components are connected by quick unloading flange. The water absorption properties of composite adsorbents containing 5% and 7.5% carbon nanotubes were tested on a new experimental platform. The experimental results show that when the adsorption temperature is 50 鈩

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