论文总字数：43262字

摘 要

空气源热泵作为一种高效节能的制热技术在我国被广泛使用，但它在温度较低且湿度较大的冬季运行时，制热却效果衰减的很快，这主要是室外翅片管换热器表面结霜的原因。蒸发器的入口流量因为结霜而不断降低，换热器与空气之间由于霜的形成，换热热阻大幅增加，蒸发温度不断降低，最终使得热泵的供热能力大幅降低。本文将通过数值建模的方式研究结霜对于空气源热泵性能的影响并提出一种以最优性能为目标除霜启动控制策略。

本文利用Visual studio软件中的C 语言分别建立了压缩机、冷凝器、节流阀、蒸发器的热物理模型，并将其相互耦合得到空气源热泵的稳态仿真模型。在干球温度0℃，相对湿度80%的设计结霜工况下，通过数值模拟得到了在整个结霜过程中空气流量、结霜量、霜层厚度、蒸发/冷凝压力、吸/排气温度、压缩机功率、制热量、COP随结霜时间的变化规律。同时，改变室外环境参数，研究室外换热器进风温湿度对于机组结霜量、放热量以及COP的影响。以电加热除霜为基础，提出了空气源热泵的除霜运行周期，定义了评价机组在一个除霜周期内的性能系数COPc，得到了其在设计结霜工况下使性能系数最大的最佳除霜周期，并以此提出了空气源热泵相应的除霜启动控制策略。

关键词：空气源热泵、模型、结霜、除霜、控制

Abstract

Air source heat pump is widely used in China as a kind of energy-saving heating technology. However, the heat-generating effect of heat pump units operating in certain areas of low temperature and high humidity has not met expectations, and frost is the main culprit affecting its working efficiency. Frosting reduces the air flow at the inlet of the evaporator. Due to the formation of frost between the heat exchanger and the air, the thermal resistance of the heat exchanger is greatly increased, the evaporation temperature is continuously reduced, and the heat supply capacity of the heat pump is ultimately reduced.

In this paper, the thermal physics models of the compressor, condenser, throttle valve and evaporator were established by using the C element in the Visual studio software, and they were coupled to each other to obtain a steady-state physical model of the air source heat pump. In a standard frosting condition with a dry-bulb temperature of 0°C and a relative humidity of 80%, through numerical simulation, the trends of air flow, frost formation, frost layer thickness, evaporation/condensation pressure, suction/exhaust temperature, compressor power, heating capacity and COP with frosting time during the entire frosting process were obtained. At the same time, the outdoor environmental parameters were changed to investigate the influence of the outdoor heat exchanger inlet air temperature and humidity on the unit frost amount. Based on the electric heating defrost, the defrosting cycle of the air source heat pump is investigated and the performance coefficient COPc of the evaluation unit in a defrost cycle is defined. The optimal defrosting cycle with the largest coefficient of performance under standard frosting conditions was obtained, and the corresponding defrosting initiation control strategy of the air source heat pump was proposed.

KEY WORDS: Air source heat pump, model, frosting, defrosting, control

目 录

摘要 I

Abstract II

第一章 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 结霜原理研究 2

1.2.2 结霜对热泵结霜的影响 2

1.2.3 空气源热泵结霜特性的数值模拟与仿真 3

1.3 本文主要研究内容 4

第二章 空气源热泵冷热水机组仿真模型的建立 5

2.1 压缩机模型 5

2.2 冷凝器模型 7

2.3 节流阀模型 10

2.4 蒸发器模型 11

2.5 本章小结 15

第三章 制冷剂的物性参数及换热器的结构参数 16

3.1 制冷剂R134a的物性参数 16

3.2 换热器的结构参数 17

3.3 本章小结 17

第四章 结霜对空气源热泵性能影响研究 18

4.1 标准结霜工况下空气源热泵性能变化 18

4.2 不同室外环境参数对空气源热泵结霜特性的影响 24

4.2.1 进风温湿度对结霜量的影响 24

4.2.2 进风温湿度对机组制热量与COP的影响 26

4.3 本章小结 29

第五章 空气源热泵最佳除霜周期的研究 30

5.1 空气源热泵的除霜运行周期 30

5.2 设计结霜工况下最佳除霜周期的研究 31

5.3 空气源热泵除霜启动控制策略 33

5.4 本章小结 33

第六章 总结与展望 35

6.1 全文总结 35

6.2 未来展望 35

致谢 36

参考文献 37

附录 39

第一章 绪论

1.1研究背景与意义

剩余内容已隐藏，请支付后下载全文，论文总字数：43262字