冰球式蓄冷空调系统设计与实验研究

VIP免费
3.0 陈辉 2024-11-19 6 4 2.63MB 72 页 15积分
侵权投诉
摘 要
冰蓄冷空调系统以其“削峰填谷”的优势,获得了电力生产部门和空调用户
的青睐,已经在国内外日益得到高度重视和广泛应用。目前对系统的研究大都集
中在蓄冰槽动态特性研究,冰蓄冷空调系统优化配置,系统的经济性分析等方面。
由于冰球式蓄冷空调系统具有蓄冷密度大、空间利用效率高、设备简单、系统阻
力小、使用寿命长等优点,因而在蓄冷系统中应用的比较多。本文以冰球式蓄冷
空调系统的蓄冷槽为核心部件,从理论和实验中研究蓄冷过程和释冷过程的影响
因素。主要研究工作有以下几个方面:
1)设计并搭建冰蓄冷空调系统实验台。为了研究冰球式蓄冷系统的特性,
作者作为设计者之一,查阅了很多关于冰蓄冷系统设计的文献及原著,在总结大
量前人经验的基础上,结合场地的特点进行实验台设计。实验台采用蓄冷槽与制
冷机组串联,制冷机组优先的模式,实行分量蓄冷策略;并对制冰和空调工况下
的制冷四大部件进行选型计算。
2建立并求解蓄冷过程的数学模型。针对冰球式蓄冷槽的结构特点,考虑
冰球内水的过冷度对蓄冷过程的影响,将冰水界面包含导热、对流换热的复杂传
热现象进行简化,建立了冰球式蓄冷槽蓄冷过程的简化模型。对蓄冷槽蓄冷的影
响因——蓄冷槽的高度、冰球的大小、冰球的过冷度、载冷剂的流速、载冷剂
的进口温度等影响参数进行一一分析。
3实验研究。对影响蓄冷槽蓄冷和释冷特性的主要因素及其作用规律进行
实验研究。蓄冷槽的蓄冷过程包括液态显热蓄冷、潜热蓄冷、固态显热蓄冷阶段,
实验结果表明:整个蓄冷阶段,潜热蓄冷占整个蓄冷过程蓄冷量的 76%;乙二醇
溶液的流速是影响蓄冷过程的主要因素,而乙二醇溶液初始温度的影响较小。同
样,在蓄冷槽释冷过程中,改变冷媒水的流量对释冷过程影响不大,主要取决于
乙二醇溶液的流量。降低乙二醇溶液的流量,并且维持蓄冷槽内较低的乙二醇溶
液进口温度,可减缓释冷进程。经初步释冷实验,结果表明系统的释冷时,温度
上升比较快,系统适合负荷比较集中的场合。本实验装置能够完成蓄冷过程要求,
释冷过程只做了初步研究。
关键词:冰蓄冷 冰球 蓄冷槽 数学模型 特性分析
ABSTRACT
The ice storage air-conditioning system has won the power production department
and air conditioning users favor with its advantage of reducing the peak power
requirement. Now the system has been getting more and more attention and being
widely used at home and abroad. The current points of research are concentrated in the
dynamic characteristics of ice storage tank, the optimization allocation and the
economical analysis of the system, and so on. Because of high storage density, high
efficiency in space utilization, simple equipment, small system resistance and long
service life, the storage system filled with ice balls is widely used. Based on storage
tank filled with ice balls as the core components of the storage air-conditioning system,
the author mainly engaged in the following research work:
(1) Design and build the ice storage air-conditioning system test plant. In order to
study the ice ball type storage system characteristics, the author as a designer, consulted
a lot of summarizing literature and original about design of ice storage system, then on
the basis of predecessors' experience, combined with the characteristics of the building
in designing the test plant. The designed ice-storage system made the chiller and storage
tank in series and the chiller located in the upper reaches with the implementation of
component cold storage strategy. There are comparison in calculation and selection of
the four fundamental refrigeration parts under the charging process and air conditioning
condition.
(2) Established and solved the mathematical model of the charging process. When
establishing the mathematical model of the cold storage process, the author took
structural characteristics of the storage tank and the subcooling of the ice ball in cold
storage process into consideration. In view that the influence of water-ice interface
includes heat conductivity and convective, the author simplified the complex
phenomenon and established mathematical model of the charging process. The
influencing factors are analyzed such as storage tank's height, ice ball size, subcooling,
velocity and inlet temperature of secondary refrigerant, initial temperature of secondary
refrigerant and cold storage agent and so on.
(3) Experiment research. Take into consideration of main factors that affect the
charging process and discharging process of the storage tank and their roles of the law
when to do experimental study. The charging process of the storage tank includes liquid
sensible heat storage stage, latent heat storage stage and solid-state sensible heat storage
stage. Experimental results show that latent heat storage accounted for 76% of the entire
storage capacity. The flow of glycol solution had main influence on charging process,
while the initial temperature of glycol solution had little. The effect is not obvious when
changing flow of the cooling water in discharging process. When reduced the flow of
the ethylene glycol solution and maintain its temperature lower, the discharging process
can last more time. With fast discharging rate, this system is more suitable for
concentrated occasion. After the preliminary discharging experiments, the result shows
that temperature of cooling water and ethylene glycol solution rose faster, so the system
is more suitable for load concentrated occasion. The charging process shows good
performance in heat transfer, but for discharging process still need further study.
Key Words: ice storage, ice ball, ice storage tank, mathematical model,
properties
目 录
摘 要
ABSTRACT
第一章 .............................................................................................................1
§1.1 蓄冷空调技术的应用背景........................................................................................... 1
§1.2 蓄冷空调技术的研究意义........................................................................................... 1
§1.3 蓄冷空调技术的发展历史及现状............................................................................. 3
§1.3.1 国内蓄冷空调技术的发展及现状..................................................................... 3
§1.3.2 国外蓄冷空调技术的发展及现状..................................................................... 4
§1.4 本文的主要研究内容.................................................................................................... 5
第二章 蓄冷概述 .........................................................................................................7
§2.1 冰蓄冷系统的分类........................................................................................................7
§2.1.1 全量蓄冰和分量蓄冰........................................................................................... 7
§2.1.2 静态制冰和动态制冰........................................................................................... 8
§2.2 蓄冷空调系统工作流程..............................................................................................15
§2.3 蓄冷空调系统的控制策略......................................................................................... 16
第三章 冰球式蓄冷空调系统双工况制冷机组的设计 ...........................................18
§3.1 设计对象........................................................................................................................ 18
§3.2 蓄冷周期逐时负荷分配图........................................................................................18
§3.3 本实验台制冷机组的设计........................................................................................19
§3.3.1 压缩机的选型计算...............................................................................................21
§3.3.2 蒸发器的选型计算..............................................................................................23
§3.3.3 冷凝器的选型计算..............................................................................................24
§3.3.4 节流阀的选型计算..............................................................................................25
§3.3.5 其他关键设备的选择......................................................................................... 27
§3.4 实验台的控制策略......................................................................................................31
§3.5 本章小结........................................................................................................................ 32
第四章 冰蓄冷系统中蓄冷槽的理论分析 ...............................................................33
§4.1 传热过程分析方法.......................................................................................................33
§4.2 建立蓄冷工况的模型及求解.................................................................................... 34
§4.2.1 研究对象的描述................................................................................................... 34
§4.2.2 蓄冷工况数学模型的建立.................................................................................34
§4.2.3 蓄冷工况能量平衡方程的建立........................................................................35
§4.2.4 特殊阶段................................................................................................................. 38
§4.2.5 方程的求解.............................................................................................................39
§4.3 影响参数分析................................................................................................................ 42
§4.3.1 乙二醇溶液的流量 G的变化对蓄冷过程的影响..................................... 42
§4.3.2 乙二醇溶液的进口温度 Tfin 的变化对蓄冷过程的影响.......................... 43
§4.3.3 乙二醇溶液和 PCM 的初始温度 Tfi 对蓄冷过程的影响.........................44
§4.3.4 PCM 的过冷度△T对蓄冷过程的影响 .........................................................44
§4.3.5 冰球的大小 D对蓄冷过程的影响................................................................. 45
§4.3.6 冰球的壁厚δ和球壁材料对蓄冷过程的影响............................................. 46
§4.3.7 蓄冷槽内的孔隙率ε对蓄冷过程的影响.......................................................47
§4.3.8 蓄冷槽的高度 L对蓄冷过程的影响.............................................................48
§4.4 本章小结........................................................................................................................ 49
第五章 冰球式蓄冷系统性能的实验研究 ...............................................................50
§5.1 数据采集系统............................................................................................................... 50
§5.2 实验方案........................................................................................................................ 51
§5.2.1 测试方法和实验内容.......................................................................................... 52
§5.2.2 运行步骤及注意事项......................................................................................... 53
§5.3 实验结果与分析.......................................................................................................... 54
§5.3.1 蓄冷工况性能分析..............................................................................................54
§5.3.2 释冷工况性能分析..............................................................................................57
§5.4 本章小结........................................................................................................................ 61
第六章 结论与展望 ...................................................................................................62
§6.1 结论................................................................................................................................. 62
§6.2 后续工作........................................................................................................................ 63
§6.3 展望................................................................................................................................. 63
参考文献 .....................................................................................................................65
在读期间公开发表的论文和承担科研项目及取得成果 .........................................68
.........................................................................................................................69
第一章 绪 论
1
第一章 绪
§1.1 蓄冷空调技术的应用背景[1,2,3,4]
随着经济的发展和人民生活水平的不断提高,人们对生活和工作环境的舒适
性要求的提高,使得中央空调的需求量越来越大,一些大、中城市空调用电量已
占其高峰用电量的 35%以上,导致电力系统尖峰电力负荷时段的全国电力需求量
增长快于可提供的用电量的增长,使得峰谷差加大,电网负荷率下降,最终导致
电力部门不得不拉闸限电[1]
近几年,我国的电力行业发展较快,电力部门通过增加相关电力设施,用以
缓解普遍缺电的状况,但随着电力消费量的增加,白天与深夜的电网负荷存在很
大的峰谷差,而且这种矛盾是越来越突出。调节电厂发电能力或调节用户负荷这
两种方法都能够达到平衡电网负荷的目的。而在这两种方法中,调节电厂发电
力的方法,除水力或电力发电厂外,对火力发电机组发电功率的调节是困难和不
经济的;而核电站要求供电平稳;若采用建抽水蓄能电站方法,其一次性投资很
大,加上水泵、电机效率低的影响,储能的回收率也只有 60%左右,蓄能的成本
增加,从能源的有效利用率来看,这并不是一种理想的方法。另外最大的问题就
是电网容量有限,即使电厂可以增加峰电供应,也因供电网能力的限制,对用户
而言,仍然会存在高峰缺电状况。因此,调节用户负荷是一种更为有效的方法。
据统计,目前我国空调的年耗电量为 400 亿kW·h 以上,随着空调的普及,
个数据还将进一步增加。空调已日渐成为能耗大户,夏季尤其是南方一些城市空
调的耗电量占到城市用电量的 30%40%[3]而且经研究发现空调日负荷曲线同电
网用电负荷曲线同步,而空调的年运行负荷率低,一般达到设计负荷 50%以下的
运行时间占全年运行时间的 70%[4]蓄能空调技术不仅可以对用户侧进行电力负荷
管理、改善电力负荷的昼夜峰谷差,提高电网的负荷率,而且还可以降低空调
统的运行费用,因此受到人们的广泛关注。
§1.2 蓄冷空调技术的研究意义[1,5,7]
蓄冷空调技术特别是相变储能技术是缓解能量供求双方在时间、强度和地点
上不匹配的有效形式[6]具有良好的社会效益和经济效益。由于蓄冷空调系统相对
于普通的中央空调系统具有设备多、工况多而复杂等特点,因此研究者对系统
计及其经济性进行分析研究。
摘要:

摘要冰蓄冷空调系统以其“削峰填谷”的优势,获得了电力生产部门和空调用户的青睐,已经在国内外日益得到高度重视和广泛应用。目前对系统的研究大都集中在蓄冰槽动态特性研究,冰蓄冷空调系统优化配置,系统的经济性分析等方面。由于冰球式蓄冷空调系统具有蓄冷密度大、空间利用效率高、设备简单、系统阻力小、使用寿命长等优点,因而在蓄冷系统中应用的比较多。本文以冰球式蓄冷空调系统的蓄冷槽为核心部件,从理论和实验中研究蓄冷过程和释冷过程的影响因素。主要研究工作有以下几个方面:(1)设计并搭建冰蓄冷空调系统实验台。为了研究冰球式蓄冷系统的特性,作者作为设计者之一,查阅了很多关于冰蓄冷系统设计的文献及原著,在总结大量前人...

展开>> 收起<<
冰球式蓄冷空调系统设计与实验研究.pdf

共72页,预览8页

还剩页未读, 继续阅读

作者:陈辉 分类:高等教育资料 价格:15积分 属性:72 页 大小:2.63MB 格式:PDF 时间:2024-11-19

开通VIP享超值会员特权

  • 多端同步记录
  • 高速下载文档
  • 免费文档工具
  • 分享文档赚钱
  • 每日登录抽奖
  • 优质衍生服务
/ 72
客服
关注