【作者】 王斌；

【导师】 刘俊杰；

【作者基本信息】 天津大学 ， 供热、供燃气、通风与空调工程， 2007， 硕士

【摘要】 很多种合金都可以与氢反应生成金属氢化物,像稀土类这样的金属在与氢反应过程中产生的较高化学能可以被用来实现制冷或制热的功能。特别是在氟利昂类制冷工质退出历史舞台,各种各样新型的替代物不断涌现出来的今天,以金属氢化物为工质的热泵空调因其出色的环保和可利用低品位能源的性质,越来越受到人们的关注。目前,金属氢化物热泵空调正处于研发阶段,为了更好的指导样机的开发,应该首先进行完善的理论研究。本文在介绍金属氢化物的特性的基础上,结合国内外现有的研究成果,分析了金属氢化物热泵空调循环的原理和特点,并指出了其在应用中存在的问题和需要改进的方向。在对金属氢化物反应的热力学和动力学性能研究进行了深入总结和分析之后,建立了金属氢化物制冷循环的动态集总参数法理论模型,利用一对金属氢化物MmNi4.5Al0.5/MmNi4.2Al0.1Fe0.7作为工质对进行模拟,得到了各个参数在整个循环过程中的动态参数变化情况。为了验证理论模型的正确性,搭建了以LaNi5/LaNi4.7Al0.3为工质对的金属氢化物制冷循环的实验台进行了验证性实验,测量了整个循环过程中的各步骤的反应时间及温度和压力的变化趋势,实验结果的变化趋势与理论模型的分析结果基本一致。通过改变输入参数的方法,利用模拟程序,对金属氢化物制冷循环效果产生影响的控制和输入因素进行了逐一分析,得到了各个参数对系统性能的影响趋势。根据参数分析的结果,对系统的参数进行优化后,在不改变工质对的条件下对制冷循环性能进行了重新计算。结果表明,参数的优化能使制冷循环的效果大大提高。这些参数中,对制冷效果影响最大的是制冷过程时间和反应器的传热特性,由于制冷过程时间仅为控制因素,因而传热特性的提高才是金属氢化物反应器性能优化的关键。更多还原

【Abstract】 Under some special condition, a lot of alloys can react with hydrogen to be metal hydrides. The thermal energy discharged or charged from these reactions by some of the alloys such as the less common metals when absorbing or desorbing hydrogen can be used in cooling or heating process. Nowadays, as the Freon refrigerator is banned, various substances are made. Because of the characters of environment protecting and making use of the waste heat, metal hydride heat pump becomes to the most promising one of them. In order to guide the research on the prototype, the theoretical study must be done.Based on the introduction of the reaction characteristics and the former studies and applications of the metal hydrides, this paper studied the operation principle and characteristics of the metal hydride heat pump and gave some improving advices. A lumped-parameters numerical model was built to study the dynamic process of the refrigeration cycle with MmNi4.5Al0.5/MmNi4.2Al0.1Fe0.7. A test platform of the same parameters with LaNi5/LaNi4.7Al0.3 was built to validate the model. Both the temperature and pressure values of the whole cycle were recorded. The test results had the same trends with the theoretical results. The operation parameters which can influence the performance of the system were studied respectively. Based on the study result, the numerical model was refined with the improved parameters.The result showed that the performance of the system could be improved greatly. The most important parameters of the refrigeration cycle were the length of the refrigeration process and the heat transfer character of the reactors. Because the length of the refrigeration process was just a control parameter, the improvement of the heat transfer character of the reactors was the key point to improve the performance of the system.更多还原