50kW燃气驱动小型氨水吸收式热泵系统设计与性能优化分析

 2022-04-12 07:04

论文总字数:30344字

摘 要

目前,北方常用的供暖方式为燃气锅炉供暖,即化石燃料燃烧产生的热量直接用于供暖,但燃气锅炉供暖有许多的弊端,高位能源在简单直接利用下浪费较大,供热效率仅有90%~95%。除此之外,燃气锅炉还会出现因锅炉缺水、水垢过多或压力过大等情况而爆炸的危险事故,严重危害居民的生命安全。为了改善北方供暖问题,优化能源结构,我国大力推广煤改电工程,即逐步取缔直热式电取暖设备,鼓励使用具有能效高、清洁环保、可利用环境废热的空气源热泵,并在试点后得到了良好的反馈。

因此,本文将对燃气驱动型氨水吸收式热泵进行设计计算,并对计算结果进行分析,优化。首先将分析工质的热力性质,并对热力系统进行建模。在系统的热力计算中,根据氨的热力性质表和氨水焓浓图可得到每个状态点的详细参数,由此可计算出相应的热力系数值。为了确立系统的最佳工况点,本设计采取变工况的方法,即改变系统的热源温度、冷却水温度、蒸发温度三个条件,根据计算结果分析出最佳工况点为:冷却水温度40℃,热源温度150℃,蒸发温度-10℃,计算出在该工况条件下,热泵COP为1.42。并对发生器,吸收器进行设计优化。

关键词:氨水,吸收式热泵,空气源热泵,变工况

Abstract

At present, the commonly used heating mode in North China is gas-fired boiler heating, that is, the heat generated by fossil fuel combustion is directly used for heating, but there are many drawbacks in gas-fired boiler heating. High-level energy is wasted greatly under simple and direct utilization, and the heating efficiency is only 90%-95%. In addition, gas-fired boilers may also occur explosion accidents due to water shortage, excessive scale or excessive pressure, which seriously endangers the lives of residents. In order to improve the heating problem in the north and optimize the energy structure, China has vigorously promoted the coal-to-electricity project, i.e. gradually banning direct-heating electric heating equipment, encouraging the use of air-source heat pumps with high energy efficiency, clean and environmental protection, and utilizing environmental waste heat, and received good feedback after the pilot project.

Therefore, this paper will design and calculate the gas-driven ammonia-water absorption heat pump, and analyze and optimize the calculation results. Firstly, the thermodynamic properties of the material are analyzed and the thermodynamic system is modeled. In the thermodynamic calculation of the system, the detailed parameters of each state point can be obtained according to the thermodynamic property table of ammonia and the enthalpy concentration diagram of ammonia, and the corresponding thermodynamic coefficients can be calculated accordingly. In order to establish the optimal operating point of the system, the design adopts the method of variable operating conditions, namely changing the three conditions of heat source temperature, cooling water temperature and evaporation temperature. According to the calculation results, the optimal operating point is: cooling water temperature 40℃, heat source temperature 150℃, evaporation temperature - 10℃. The heat pump COP is calculated to be 1.42 under this operating condition. The generator and absorber are designed and optimized.

KEY WORDS: ammonia water, absorption heat pump, air source heat pump, off-design condition

目 录

摘要............................................................................................................................................Ⅰ

Abstract........................................................................................................................................................Ⅱ

  1. 绪论...............................................................................................................................1

1.1 研究背景与意义........................................................................................................1

1.2 国内外研究现状........................................................................................................1

1.2.1 氨水吸收式热泵的起源与背景.....................................................................1

1.2.2 对于氨水吸收式热泵性能的优化研究.........................................................2

1.2.3 GAX循环..........................................................................................................4

1.3 总结............................................................................................................................4

  1. 热力计算.......................................................................................................................6

2.1热泵系统及计算工况设定.........................................................................................6

2.2循环参数的确定.........................................................................................................6

2.3设备的热负荷计算.....................................................................................................11

2.3.1设备单位热负荷..............................................................................................11

2.3.2循环量计算......................................................................................................11

2.3.3设备负荷计算..................................................................................................11

2.3.4热平衡相对误差计算......................................................................................13

2.4主要消耗指标计算.....................................................................................................14

  1. 变工况分析...................................................................................................................15

3.1热源温度发生变化时.................................................................................................15

3.2蒸发温度发生变化时.................................................................................................16

3.3冷却温度发生变化时.................................................................................................17

  1. 换热器计算...................................................................................................................19

4.1吸收器.........................................................................................................................19

4.1.1吸收器的形式与选择......................................................................................19

4.1.2吸收器的热力计算..........................................................................................20

4.2发生器.........................................................................................................................21

4.2.1发生器的结构与原理......................................................................................21

4.2.2发生器的热力计算..........................................................................................22

  1. 总结与展望...................................................................................................................26

5.1总结.............................................................................................................................26

5.2对氨水吸收式热泵的展望.........................................................................................26

参考文献(References)...........................................................................................................28

致谢.............................................................................................................................................30

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