上海地区地源热泵单U形地埋管换热器运行特性研究

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摘要

随着科学技术的不断进步，空调行业的不断发展，各种新型的热泵系统不断

出现。其中，利用地热能源越来越多，相关的一个热泵系统便应运而生-地源热

泵系统，该系统由于其自身的高效、节能、环保等一系列优良特性，近年来日益

得到人们广泛的重视。但是，在应用和推广这项高效节能的热泵关技术，最关键

的就是解决地下管井与土壤之间的传热问题。

针对地下埋管换热情况的研究，已经有很多的模型与算法，其中主要有两大

类：解析法和数值法，但各自都有缺陷，因此在研究地埋管与周围土壤换热过程

中，除了用软件辅助模拟传热过程外，更重要的是进行实测，揭示地源热泵在实

际运行过程中地下埋管与周围土壤之间的换热过程。

本文结合上海地区某工程实训中心地源热泵科研项目，建立地源热泵实验

台，用 GAMBIT 软件进行数学建模，用 FLUENT 软件进行三维传热和流动计算，

并进行冬夏季地埋管运行实验，揭示地埋管换热器在冬夏季的运行特性。

本文建立的地埋管模型主要为单 U型管，输入的参数均是根据实际情况所

输入的，虽然做了一些假设，与实际有一定的误差，但是结果均在实验结果的允

许误差以内。实验主要在所建立的地源热泵实验台上进行，冬夏季均是间歇性运

行，一天运行 8小时。实验过程中所用的温度测量仪器及流量测量均进行了校验，

确保实验的误差率。

本文模拟主要针对冬、夏季地源热泵运行时，地下不同深度土壤温度及同一

深度随着时间的温度变化及不同间距埋管区域两埋管井间的相干性影响。实验主

要分析了不同井数区域的地埋管换热器的换热量及单位井深的换热量；分析不同

间距地埋管区域的换热器中进出水温变化及地埋管区域不同深度土壤温度变化；

分析地源热泵在停机以后，地下不同深度土壤温度恢复情况；分析地源热泵运行

时，地源热泵机组本身的 COP 实时变化及整个系统的 COP 变化，通过以上相关

分析，得出单 U型地埋管换热器的换热性能及地源热泵系统的制冷、供暖特性，

提出了一些建议，供实际工程中参考及后续研究。

关键词：地源热泵单U型地埋管运行特性数值模型上海地区

ABSTRACT

With the development of science and technology, the air-conditioning industry

increasingly development, many new heat pump systems appear increasingly. The

geothermal energy is being used more and more, and a related heat pump

system ,called ground source heat pump system, is emerging. The system has received

widespread attention in recent years, for its high efficiency, energy saving,

environmental protection and several other excellent properties. However, a critical

problem of applying and promoting the high-efficiency and energy-saving heat pump

technology is the heating exchanging between underground pipe and soil surround.

Many models and algorithms about the underground heat exchanger have been

raised: analytic method and numerical method. None of the methods are perfect

enough when compared with the actual truth about the underground heating

exchanging when operating the ground source heat pump. In order to discover the real

process of heating exchange between the underground pipes and the soil around,

experiment is important when compared with the software simulation.

Based on a ground source heat pump project in Shanghai area, a ground heat

pump system is being established. GAMBIT software is being used for mathematical

modeling and FLUENT software is used to calculate the three-dimensional heating

transfer and flow. Experiments are being done to reveal characteristics of the

underground heat exchanger when operating the ground heat pump system in summer

and winter.

The input parameters of the model for a single U pipe are based on the actual

situation. The modeling results are localized within allowable error although some

assumptions are being made which will lead some errors compared with the reality.

The experiments are being made mainly on the ground source heat pump system,

whenever in winter or summer, 8 hours a day. Temperature and water flow measuring

instruments were all checked before using to ensure the measuring error.

The simulation in this paper is mainly for the soil temperature of different

underground depth and the same depth in different time when operating the ground

heat pump system in summer and winter. Besides, the coherence effect between the

two wells with different spacing is also simulated after operating the ground source

heat pump in a whole summer and winter. The experiments mainly analysis the

different area and unit well heating exchange, the water temperature of the input and

output ground heat exchange pipes and the soil temperature of different depth in

different spacing region, the soil temperature recovery of different depth after

stopping operating the ground source heat pump, the cop variation with the time of

ground source heat pump and the whole system. By the analyzation above, a

conclusion can be reached that the cooling and heating characteristics of single

ground U-tube heat exchanger, some suggestions will be also put forward for the

following research in practical engineering to refer.

Key Word: Ground heat pump system, Single ground U pipe,

Operating characteristics, Numerical model, Shanghai District

中文摘要

ABSTRACT

第一章绪论.............................................................................................................. 1

1.1 课题研究背景 ..................................................................................................... 1

1.2 地源热泵原理及发展 ......................................................................................... 2

1.3 地埋管换热器国内外研究现状 ......................................................................... 3

1.4 本课题研究目的 ................................................................................................. 5

1.5 本课题研究内容 ................................................................................................. 5

第二章地源热泵系统建筑物冷热负荷变化特性...................................................... 7

2.1 不同建筑物的负荷特性 ..................................................................................... 7

2.2 建筑物概况 ......................................................................................................... 7

2.3 工程实训中心全年负荷模拟 ............................................................................. 8

2.3.1 建立建筑物模型........................................................................................... 8

2.3.2 上海地区全年室外温湿度变化................................................................... 8

2.3.3 上海地区全年舒适区域分析....................................................................... 9

2.3.4 建筑物模型全年负荷................................................................................. 11

2.4 本章小结 ........................................................................................................... 12

第三章地埋管换热器理论及模拟............................................................................ 13

3.1 地埋管换热器传热模型 ................................................................................... 13

3.1.1 钻孔内传热模型......................................................................................... 13

3.1.1.1 一维导热模型 ...................................................................................... 13

3.1.1.2 二维导热模型 ...................................................................................... 14

3.1.1.3 单U型准三维模型 ............................................................................. 16

3.1.2 钻孔外传热模型......................................................................................... 18

3.1.2.1 一维无限长线热源传热模型 .............................................................. 18

3.1.2.2 一维圆柱孔热源传热模型 .................................................................. 19

3.1.2.3 有线长线热源模型 .............................................................................. 19

3.1.2.4 有限长圆柱面热源模型 ...................................................................... 20

3.2 地埋管数值法简介 ........................................................................................... 21

3.2.1 有限差分法................................................................................................. 21

3.2.2 有限元法..................................................................................................... 22

3.2.3 有限容积法................................................................................................. 22

3.3 单U型地下埋管数学模型 ............................................................................ 22

3.4 垂直单 U型地埋管换热器模型 ...................................................................... 23

3.4.1 土壤初始温度............................................................................................. 23

3.4.2 垂直单 U型地埋管模型建立 .................................................................... 24

3.4.2.1 物理模型 .............................................................................................. 24

3.4.2.2 模型简化条件 ...................................................................................... 24

3.4.2.3 模型网格划分 ...................................................................................... 24

3.4.2.4 边界条件 .............................................................................................. 25

3.4.3 FLUENT 数学模型求解 ............................................................................. 26

3.4.3.1 选择模型 .............................................................................................. 26

3.4.3.2 设置步长 ............................................................................................ 27

3.4.3.3 求解框图 ............................................................................................ 27

3.4.4 模型输入参数 ............................................................................................ 28

3.5 本章小结 ........................................................................................................... 28

第四章单U形地埋管地源热泵实验台设计 ........................................................... 29

4.1 工程实训建筑物全年动态冷、热负荷 ........................................................... 29

4.2 空调设备选型 ................................................................................................... 29

4.3 实验台概况 ....................................................................................................... 31

4.4 地埋管设计 ....................................................................................................... 33

4.4.1 地埋管换热器负荷的确定......................................................................... 33

4.4.2 地埋管回路形式......................................................................................... 33

4.4.3 水平间距..................................................................................................... 34

4.4.4 管材的选用................................................................................................. 34

4.4.5 地埋管换热器尺寸设计............................................................................. 35

4.4.5.1 土壤热物性 .......................................................................................... 35

4.4.5.2 单位井深换热量 .................................................................................. 35

4.4.5.3 埋管管数及管径 .................................................................................. 36

4.4.5.4 水力平衡 ............................................................................................... 36

4.4.6 地埋管换热器施工..................................................................................... 37

4.5 本章小结 ........................................................................................................... 38

第五章地埋管换热器运行特性研究实验方案........................................................ 40

5.1 实验目的 ........................................................................................................... 40

5.2 实验数据采集内容 ........................................................................................... 40

5.3 实验测量系统 ................................................................................................... 40

5.3.1 实验温度测点............................................................................................. 40

5.3.2 温度测点布置............................................................................................. 41

5.3.3 流量测点布置............................................................................................. 42

5.4 实验采集系统 ................................................................................................... 42

5.5 数据处理方法 ................................................................................................... 43

5.6 本章小结 ........................................................................................................... 44

第六章实验数据处理与分析.................................................................................... 45

6.1 夏季实验分析 ................................................................................................... 45

6.1.1 夏季地源热泵运行室内外温度................................................................. 45

6.1.2 地源热泵未运行时，地下不同深度土壤温度变化................................. 46

6.1.2 夏季地源热泵运行时不同深度土壤温度场分布..................................... 46

6.1.2.1 地埋管井 A、B、C三块区全开启，地下不同深度土壤温度 ........ 46

6.1.2.2 地埋管井 A、C区开启 B区关闭时，地下不同深度土壤温度 ...... 49

6.1.3 夏季地源热泵运行时地埋管进出口水温变化......................................... 50

6.1.4 夏季地源热泵运行时，A区域地下 50m 处进出管径向温度................ 51

6.1.5 夏季地源热泵停机后地下水温变化......................................................... 52

6.1.6 夏季地埋换热器换热量............................................................................. 53

6.1.7 夏季地源热泵循环性能............................................................................. 55

6.2 冬季实验分析 ................................................................................................... 57

6.2.1 冬季地源热泵运行室内外温度................................................................. 57

6.2.2 冬季地源热泵运行下的地下不同深度的土壤温度场分布..................... 57

6.2.2.1 地埋管井 A、B、C三区全开启时，地下不同深度土壤温度 ........ 57

6.2.2.2 地埋管井 A、C区开启 B区关闭时，地下不同深度土壤温度 ...... 58

6.2.3 冬季地源热泵运行时地埋管进出口水温变化......................................... 60

6.2.3.1 地埋管井 A、B、C三块区域全开启时，地埋管进出口水温 ........ 60

6.2.3.2 地埋管井 A、C区域开启，B区域关闭时，地埋管进出口水温 ... 61

6.2.4 冬季地源热泵运行时，A区域地下 50m 进出管径向温度.................... 61

6.2.5 冬季地源热泵停机后地下水温变化.......................................................... 62

6.2.6 冬地埋换热器换热量.................................................................................. 63

6.2.7 冬季地源热泵循环性能.............................................................................. 63

6.3 本章小结 ........................................................................................................... 64

第七章模拟与实验结果对比分析............................................................................ 68

7.1 模型实验验证 ................................................................................................... 68

7.1.1 实验简介..................................................................................................... 68

7.1.2 验证目的..................................................................................................... 68

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摘要：

摘要随着科学技术的不断进步，空调行业的不断发展，各种新型的热泵系统不断出现。其中，利用地热能源越来越多，相关的一个热泵系统便应运而生-地源热泵系统，该系统由于其自身的高效、节能、环保等一系列优良特性，近年来日益得到人们广泛的重视。但是，在应用和推广这项高效节能的热泵关技术，最关键的就是解决地下管井与土壤之间的传热问题。针对地下埋管换热情况的研究，已经有很多的模型与算法，其中主要有两大类：解析法和数值法，但各自都有缺陷，因此在研究地埋管与周围土壤换热过程中，除了用软件辅助模拟传热过程外，更重要的是进行实测，揭示地源热泵在实际运行过程中地下埋管与周围土壤之间的换热过程。本文结合上海地区某工程实训中...

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