共晶盐蓄冷材料的研制及特性的研究

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3.0 牛悦 2024-11-19 4 4 4.86MB 80 页 15积分
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摘 要
随着经济的发展和人民生活水平的提高，我国电力供应日益紧张，夏季城市
电网供需矛盾尤为突出。蓄冷技术作为电力负荷管理策略的一项重要技术手段，
应用于空调系统，可以起到移峰平谷，平衡电力负荷的作用。目前常用的蓄冷介
质主要有水、冰、气体水合物和共晶盐，水蓄冷系统体积太大，冰蓄冷系统蒸发
温度太低，共晶盐介于两者之间，具有相变温度高、蓄冷密度大的优点，在工程
应用中发挥节能效益，实现能源利用和环境保护的双重目的。
但是共晶盐相变材料也存在一些缺点，如：过冷度较大、性能不稳定、固-液
相分离现象严重、易老化等。这些缺点制约了共晶盐材料在实际工程中的应用。
因此对共晶盐相变材料性能的研究以及对新型材料的研制，一直是国内外专家学
者关注的重要课题。
本课题主要内容是在对共晶盐相变蓄冷材料的原理进行学习的基础上，查阅
了大量国内外文献，设计了实验系统，动手研制了一种适用于蓄冷空调系统的共
晶盐材料，对材料的蓄冷过程进行了细致的对比实验，对材料的关键性能获得了
定量的结论，并对材料的物性参数进行了理论计算。
主要工作和成果有以下几点：
1) 在众多的无机盐及其水合盐材料中筛选得到了一种适用于蓄冷空调系统的
共晶盐相变材料的配方，并申请了发明专利；
2) 运用了化学热力学、材料学、结晶动力学的理论分析了共晶盐材料的相变
蓄冷原理，了解了过冷度对共晶盐蓄冷材料结晶过程的影响，提出了采用添加辅
助材料降低共晶盐过冷度的理论依据；
3) 设计了实验的方案，搭建了实验系统。并运用 VB 程序语言，编制了该实
验装置的数据采集软件。
4) 通过大量细致的实验与数据处理，分析了各组分材料性能，对该配方添加
了合适比例的辅助材料，使共晶盐材料的过冷度、相分离等现象得到了较好的改
善，稳定性得到提高。
5) 经过理论计算，研制的共晶盐相变蓄冷材料的固态比热容为 1.42
kJ/(kg·℃)，液态比热容为 2.29 kJ/(kg·℃)；相变潜热量为：137.94～185.24 kJ/kg。
关键词：共晶盐 结晶动力学 过冷度 步冷曲线 实验研究 理论计算
ABSTRACT
With the development of economy and the improvement of people's living
standard, the power supply is becoming increasingly tense in China. The imbalance of
urban power between supply and demand in summer is particularly prominent. As one
of the important effectual techniques of the power load management strategy, the
storage technology can not only shift electric load from on-peak period to off-peak
period but also average electric-load in all daytime. The normal storage medium at
present include: water, ice, gas hydrate and eutectic salt. The chilled water storage
system has a big cubage, and the ice storage system has a lower evaporation
temperature. The eutectic salt phase change materials have more advantages over ice
and water.
But the eutectic salt phase change materials also have some disadvantages. Such
as the problems of supercooling and phase segregation during the phase change
process. Because of these shortcomings, the eutectic salt phase change materials can
not be widely used in practical engineering applications. So the performance research
and the development of the eutectic salt phase change materials has always been an
important scientific research work.
The main task of this paper is to study crystallization principle of eutectic salt
phase change thermal storage materials and to develop a new kind of eutectic salt
material. The major work and results are as follows:
1) A kind of eutectic salt material has been developed in this paper, which could
be used for storage air-conditioning System.
2) According to the chemical thermodynamics theory, materials science and
crystallization kinetics theory, firstly, the phase change cool storage principle of
eutectic salt has been analyzed in this paper, secondly, the affection of supercooling
degree on eutectic salt storage material crystallization process has been grasped , and
thirdly, theoretical basis for adding supplementary material to reduce the use of
eutectic salt cooling degree has been proposed.
3) Not only a new kind of experimental program has been designed but also a new
kind of experimental system has been built here. Meanwhile a new kind of data
acquisition software of the experimental system has been developed by using VB
programming language too.
4) Through both repeated and detailed experiments and data processings, and after
analyzing the property of the material components, appropriate proportion of auxiliary
materials have been added to the formula, consequently, eutectic salt materials
supercooling degrees and phase separation phenomenon have been better improved
and stability has been improved too.
5) Through theoretical calculations, the physical parameters of the eutectic salt
material we developed are as follows: its solid specific heat capacity: 1.42 kJ/(kg•℃),
its liquid specific heat capacity : 2.29 kJ/(kg•℃); and its phase transformation latent
heat: 137.94 ~ 185.24 kJ/kg.
Keywords: Eutectic Salt, Crystallization Dynamics, Supercooling
Degree, Step Cooling Curve, Experimental Study,
Theoretical Calculation
目 录
摘 要
ABSTRACT
第一章 绪 论 .................................................................................................................1
§1.1 课题研究背景 ....................................................................................................... 1
§1.1 .1 我国电力发展现状 ........................................................................................1
§1.1.2 分时电价与“移峰填谷” ................................................................................. 1
§1.1.3 蓄冷空调技术的意义与发展 .........................................................................2
§1.2 蓄冷空调方式及其优缺点 ................................................................................... 3
§1.3 课题来源与意义 ................................................................................................... 4
§1.3.1 课题来源 .........................................................................................................4
§1.3.2 课题意义 .........................................................................................................4
§1.4 相变蓄能材料的国内外研究应用进程与现状 ................................................... 5
§1.4.1 相变蓄能材料研究的历史 .............................................................................5
§1.4.2 国外相变蓄能材料研究的状况 .....................................................................5
§1.4.3 国内相变蓄能材料研究的状况 .....................................................................6
§1.5 本课题研究内容 ................................................................................................... 7
第二章 共晶盐相变蓄冷的机理 .....................................................................................8
§2.1 相律和相图 ........................................................................................................... 8
§2.1.1 相律 .................................................................................................................8
§2.1.2 相图及有关理论 ...........................................................................................10
§2.1.3 相平衡特性和单元系相图 ...........................................................................11
§2.1.4 二元共晶系相图 ...........................................................................................13
§2.2 结晶动力学原理 ................................................................................................. 14
§2.2.1 结晶机理 .......................................................................................................14
§2.2.2 晶核的形成与成长 .......................................................................................15
§2. 3 影响材料结晶过程的因素 ................................................................................ 17
§2.3.1 过冷度对相变材料结晶过程的影响 ...........................................................17
§2.3.2 难溶杂质相变材料结晶过程的影响 ...........................................................19
§2.4 本章小结 ............................................................................................................. 19
第三章 相变蓄冷材料特性与实验材料选取 ...............................................................20
§3.1 蓄冷材料选择要求、分类及特性 ..................................................................... 20
§3.1.1 蓄冷材料的选择要求 ...................................................................................20
§3.1.2 常用蓄冷材料的分类及特性 .......................................................................21
§3.2 常用共晶盐材料配制材料 ................................................................................. 24
§3.2.1 共晶盐相变材料研制的常用主材 ...............................................................24
§3.2.2 共晶盐常用降低熔点的材料 .......................................................................25
§3.2.3 常用共晶盐材料的主要问题及解决方法 ...................................................... 26
§3.3 本课题选用材料 ................................................................................................. 28
§3.4 本章小结 ............................................................................................................. 28
第四章 蓄冷材料研究的实验方案与装置 ...................................................................30
§4.1 实验目的、内容与原理 ..................................................................................... 30
§4.1.1 实验目的 .......................................................................................................30
§4.1.2 实验内容 .......................................................................................................30
§4.1.3 步冷曲线 .......................................................................................................30
§4.2 实验装置 ............................................................................................................. 32
§4.2.1 实验系统 .......................................................................................................32
§4.2.2 实验设备 .......................................................................................................32
§4.2.3 实验数据采集程序的开发 ...........................................................................34
§4.3 实验步骤和实验方法 ......................................................................................... 36
§4.3.1 实验步骤 .......................................................................................................36
§4.3.2 实验方法 .......................................................................................................37
§4.4 本章小结 ............................................................................................................. 38
第五章 相变蓄冷材料研制的实验与数据分析 ...........................................................39
§5.1 蓄冷材料相变温度的实验 ................................................................................. 39
§5.1.1 以氯化钠为辅材的相变温度的实验 ...........................................................39
§5.1.2 以氯化铵为辅材的相变温度的实验 ...........................................................40
§5.1.3 蓄冷材料相变温度实验的结果分析 ...........................................................41
§5.2 蓄冷材料过冷度的实验 ..................................................................................... 44
§5.2.1 Na2SO4·10H2O和NaCl 材料的过冷度实验 .............................................. 45
§5.2.2 Na2SO4·10H2O和NH4Cl 材料的过冷度实验 ............................................ 47
§5.2.3 蓄冷材料过冷度实验的结果分析 ...............................................................49
§5.3 蓄冷材料相分离的实验 ..................................................................................... 52
§5.3.1 加入硅胶后相变材料的冷却凝固实验 .......................................................53
§5.3.2 加入硅胶后对材料的相分离影响的试验 ...................................................56
§5.3.3 蓄冷材料相分离实验的结果分析 ...............................................................59
§5.4 蓄冷材料的熔化温度的实验 ............................................................................. 59
§5.5 蓄冷材料的稳定性的实验 ................................................................................. 60
§5.6 实验总结与创新点 ............................................................................................. 61
§5.7 本章小结 ............................................................................................................. 63
第六章 相变蓄冷材料的物性参数的理论计算 ...........................................................65
§6.1 固态和液态的比热容的理论计算 ..................................................................... 65
§6.2 相变蓄冷材料的相变潜热的理论计算 ............................................................. 67
§6.3 本章小结 ............................................................................................................. 67
第七章 总结与展望 .......................................................................................................68
§7.1 课题小结 ............................................................................................................. 68
§7.2 展望 ..................................................................................................................... 69
主要符号表 .....................................................................................................................70
参考文献 .........................................................................................................................71
在读期间发表的论文和承担的科研项目及取得成果 .................................................75
一、学术论文 ............................................................................................................. 75
二、专利申请 ............................................................................................................. 75
三、参与科研项目 ..................................................................................................... 76
致 谢 .............................................................................................................................77
摘要：

摘要随着经济的发展和人民生活水平的提高，我国电力供应日益紧张，夏季城市电网供需矛盾尤为突出。蓄冷技术作为电力负荷管理策略的一项重要技术手段，应用于空调系统，可以起到移峰平谷，平衡电力负荷的作用。目前常用的蓄冷介质主要有水、冰、气体水合物和共晶盐，水蓄冷系统体积太大，冰蓄冷系统蒸发温度太低，共晶盐介于两者之间，具有相变温度高、蓄冷密度大的优点，在工程应用中发挥节能效益，实现能源利用和环境保护的双重目的。但是共晶盐相变材料也存在一些缺点，如：过冷度较大、性能不稳定、固-液相分离现象严重、易老化等。这些缺点制约了共晶盐材料在实际工程中的应用。因此对共晶盐相变材料性能的研究以及对新型材料的研制，一直是...

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作者：牛悦 分类：高等教育资料 价格：15积分 属性：80 页 大小：4.86MB 格式：PDF 时间：2024-11-19

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