【作者】 宛超；

【导师】 刘益才；

【作者基本信息】 中南大学 ， 制冷及低温工程， 2010， 硕士

【摘要】 随着能源的日益紧张和社会对环保的日益关注,能源利用技术的要求不断提高。蓄冷技术能够实现“移峰填谷”,优化现有的电力系统能源利用结构,对蓄冷空调技术进行研究具有重要的现实意义。目前的蓄冷技术大多采用冰蓄冷技术,蓄冰槽是冰蓄冷系统中十分重要的部件,其换热性能好坏直接关系到整个蓄冰系统的性能优劣。本文主要针对盘管式蓄冰槽的换热性能进行研究,研究内容主要包括以下两个方面：(1)在一定的假设条件基础上,建立蓄冰槽模型,通过ANSYS软件模拟,研究蓄冰槽不同的结构参数,如盘管布置方式、盘管直径、盘管间距,以及载冷剂的进口温度对蓄冰槽传热特性的影响,并研究了盘管管径对载冷剂流动阻力的影响；(2)根据模拟结果,重点设计了蓄冰槽,并搭建冰蓄冷空调系统试验台,对蓄冰槽的传热特性进行实验研究。根据模拟与实验结果,主要得出以下结论：(1)对于U形盘管管束,顺排既简化了布置方式,且传热特性优于叉排,同时也满足温度场均匀的要求,故顺排比叉排更有利；(2)管束顺排时,载冷剂初始温度、管间距大小以及管径对蓄冰槽的传热特性有较大影响,当蓄冷槽体积一定、U形管直径和数量相同时,管间距越大越有利于增强蓄冷槽传热特性；在条件允许的情况下,应尽量选择管径大一些的U形管；(3)管径对流动阻力影响较小；(4)蓄冰时,蓄冷槽内最低温度-3℃,最高温度-0.9℃,相变温度-2.2℃,温度分层现象明显且过冷度较大；(5)在水中添加质量分数0.25%的硼砂能够将水的过冷度降低0.2℃并将系统COP提高0.1,可见添加一定量的硼砂有利于水的换热,提高蓄冷槽的换热性能；(6)释冷时,载冷剂进出蓄冷槽的温度变化快慢与融冰过程紧密相关,在一定阶段,进出蓄冷槽的载冷剂的温差基本保持稳定在8℃。更多还原

【Abstract】 With energy supplies intense increasingly and environmental protection being concerned on particularly, requirement of energy utilization technology enhances endlessly. Thermal energy storage technology, which helps to shift peak load on electricity, has benefit of the optimization of the existing power system of energy utilization structure, research of the cool-storage air conditioning technology has important practical significance.Ice thermal energy storage technology is used widely in the present, ice storage tank, which heat transfer performance is directly related to the performance of the ice storage system, is a very important component. This paper mainly focus on heat transfer performance of ice-on-coil storage tank. Research works mainly include the following two aspects:(1) Have established the model of ice storage tank on the basis of certain assumptions and simulated by ANSYS software to study on geometric parameters of the storage tank, such as coil layouts, diameter and space, and the influence of inlet temperature of refrigerating medium for heat transfer characteristics of the ice storage tank, as well as the influence of coil diameter for flow resistance of refrigerating medium; (2) Have designed ice storage tank particllarly and built ice storage test-bed of air-conditioning system, as well as carried study on heat transfer characteristics of the ice storage tank according to the simulation results.According to the simulation and experiment, the main results were as follows:(1) For the U-shaped coil, tubes in-line arrangement, which not only simplified layouts and enhanced the heat transfer characteristics, but also met the requirements of uniform temperature pattern, was better than staggered style to the performance of ice storage tank; (2) For U-tubes in-line arrangement, initial temperature of refrigerating medium, coil diameter and space, had a great influence on heat transfer characteristics, larger space was benefit to improving heat transfer characteristics of ice storage tank with the same diameter and number of tubes when ice storage tank volume was certain. It is believed larger diameter was tried to choose if the conditions permitted; (3) Coil diameter had less impact on flow resistance; (4) Temperature stratification of ice storage was significant and subcooled temperature was larger with the minimum temperature of-3℃, the maximum temperature of-0.9℃, and phase transition temperature of-2.2℃in freezing processes; (5) Adding mass fraction of 0.25% of borax to the water was able to reduce 0.2℃of subcooled temperature and increase 0.1 of COP, thus that adding a certain amount of borax was benefit to heat transfer and improving heat transfer performance of ice storage tank; (6)The rate of temperature change for inlet and outlet was closely related to melting process, In certain stage, difference in temperature between inlet and outlet of refrigerating medium maintained steady at 8℃.更多还原