论文总字数：20689字

摘 要

尽管空气中水蒸气含量极少，但它对人们的日常生活和许多工业生产过程及对产品和物质的贮存保管却有极大的影响。特别是在我国的南部地区，空气相对湿度比较高，夏季的时候人会感到闷热，冬季反而湿冷，与此同时，因为潮湿而加快了金属的腐蚀速度也随时在不知不觉地发生。因此，对空气的除湿就显得尤为重要。目前的除湿技术主要有冷冻除湿、吸附除湿、膜基除湿等等。本设计采用冷冻除湿技术，该技术具有能耗小，易于操作和控制，可靠性高等特点。目前广泛应用于化工、医药、食品、电子等领域。

本论文设计的是一般型升温风道除湿机，其原理是将潮湿的空气冷却到露点温度并使之析出冷凝水，然后利用冷凝器的散热量来加热除湿后的空气，从而除去空气中的水分并使空气升温。本次设计的除湿机回收了系统的冷凝器散热量，可以弥补湿空气因除湿导致的温度降低所失去的热量，体现了节能环保。但由于其空气出口温度不可调节，故适用于对温度没有要求的场所，存在一定的局限性。除湿机包括制冷系统和电气系统，其中制冷系统部件有压缩机，用于压缩制冷剂气体；蒸发器，用于对冷却空气；冷凝器，用于排出系统热并加热空气；节流阀，降低制冷剂液体压力。蒸发热交换器管内流过的制冷剂R22和湿空气换热成为饱和蒸气被吸入压缩机，压缩机将它压缩为高温高压的过热R22蒸气，排入冷凝器与除湿后的低温干燥空气换热，等压冷凝为制冷剂液体，之后通过膨胀阀降压重新进入蒸发器进行循环换热。

本论文完成了对蒸发器和冷凝器的设计，主要分成负荷计算、传热计算和结构计算三个部分。其中负荷计算部分包括对除湿过程的分析，制冷循环的热力平衡计算，由计算得到的数据选取合适的压缩机，通过压缩机的实际制冷量来确定换热器的实际负荷。传热计算部分主要是确定换热器的总传热系数，从而通过传热方程求得换热器的所需传热面积。由于风道式除湿机没有风机，需要外接风机箱来使空气循环，故需对整台除湿机进行压力降计算，为产品所需配备的风机箱提供依据。

换热器均采用叉排排列，加强气流扰动，以强化换热。在对翅片间距的选取中，考虑到蒸发器表面会有冷凝水析出可能导致空气流动通道被堵，因此，蒸发器的翅片间距应稍微取大点，保证空气能顺利流通，而冷凝器则可以选取较小的翅片间距。换热器翅片均采用整体套片式肋片，使得空气侧换热系数提高，从而提高换热器整体的换热系数，降低换热器的尺寸。为了防止胀管时翅片裂口，应将翅片孔口外沿翻边，同时也增加了翅片与管面的接触面积，并借助翻边高度保证翅片之间的间距。

通过对除湿机的设计，利用制冷来除去空气中多余的水分，并回收系统的冷凝热，是一种高效经济的除湿方法，符合节能环保的理念，对我国的国民生活和经济发展具有重大意义。

关键词：除湿机 冷冻除湿 蒸发器 冷凝器

The design of 40kg/h dehumidifier

Abstract

Although there is very little water vapor in the air, it has a great influence on people's daily life, many industrial processes as well as the storage of products and substances. Especially in the southern region of our country, the air humidity is larger, people feel sultry uncomfortable. At the same time, the damage of metal oxidation caused by the breeding of moisture and mold also occurs unconsciously at any time. Therefore, the dehumidification of air is important specially. At present, dehumidifying technology includes freezing dehumidification, adsorption dehumidification, membrane-based dehumidification and so on mainly. Freezing dehumidification is adopted in this design, which has the advantage of low energy consumption, easy operation, and high reliability. At present, it has been used in chemical industry, medicine, food, electronics and other fields widely.

A general type of heating duct dehumidifier is designed in the design, which principle is to cool the temperature of the wet air to the dew point temperature and precipitate the condensed water, and then use the heat lost from the condenser to heat the dehumidified air, so as to achieve the goal of dehumidifying and heating the air. The condensation heat of the system is recovered and makes up for the heat lost in the air due to cooling and dehumidification, which has the advantages of environmental protection and energy saving. However, due to the unadjustable air outlet temperature, it is applicable to places without temperature requirements and has certain limitation. The dehumidifier comprises a refrigeration system and an electrical system, wherein a refrigeration system component includes a compressor for compressing refrigerant gas; evaporator for cooling air; condenser for discharging system heat and heating air; throttle valve to reduce refrigerant liquid pressure. Refrigerant transfer into steam in the compressor, compressed into high temperature and pressure steam. After entering the condenser and dehumidified low-temperature air for heat transfer, it is condensed into the refrigerant liquid at room temperature and high pressure, and then enters the evaporator again through the expansion valve for circulation heat transfer.

The evaporator and condenser design has been completed, mainly divided into three parts: load calculation, heat transfer calculation and structure calculation. The load calculation part includes the analysis of the dehumidification process and the thermodynamic balance calculation of the refrigeration cycle. The actual load of the heat exchanger is determined by the actual refrigerating capacity of the compressor based on the data obtained from the calculation. The heat transfer calculation part is mainly to determine the total heat transfer coefficient of the heat exchanger, so as to obtain the heat transfer area required by the heat exchanger through the heat transfer equation. Since there is no fan for the air duct dehumidifier, it needs an external air connection cabinet to circulate the air, so the pressure drop calculation of the whole dehumidifier is needed to provide a basis for the bellows required for the product.

The heat exchangers are arranged in cross rows to enhance the flow disturbance and heat transfer. In the selection of fin spacing, considering that condensed water may precipitate from the evaporator surface, which may lead to blocked air flow passage, the fin spacing of the evaporator should be slightly larger to ensure smooth air circulation, while the condenser can select smaller fin spacing. The fins of the heat exchanger adopt integral shell fin, which increases the heat transfer coefficient on the air side, thus improving the overall heat transfer coefficient of the heat exchanger and reducing the size of the heat exchanger. In order to prevent the fin crack during tube expansion, the outer edge of the fin orifice should be flanged, and the contact area between the fin and the tube surface should also be increased, and the spacing between the fins should be guaranteed by the flanging height.

Through the design of dehumidifier, the use of refrigeration to remove water in the air, and recovery the condensation heat of system, is an efficient and economic dehumidification method, in line with the concept of energy conservation and environmental protection, to the national life and economic development of China has great significance.

Key Words: dehumidifier; freezing dehumidification; evaporator; condenser

目 录

摘 要 I

Abstract III

第一章 前言 1

1.1除湿机的重要性 1

1.1.1除湿的重要性 1

1.1.2除湿机的不可替代性 1

1.2除湿技术简介 1

1.2.1冷冻除湿 1

1.2.2压缩除湿 1

1.2.3溶液吸收除湿 2

1.2.4转轮除湿 2

1.2.5膜除湿 2

1.3冷冻除湿机工作原理 2

1.4市场前景 3

1.5未来研究方向 3

第二章 国内外除湿改进技术进展 4

2.1在蒸发器与冷凝器间增加换热器 4

2.2转轮与冷却除湿组合式系统 4

2.3冷冻极限除湿 5

2.4采用双级表冷器 5

2.5采用热管技术 6

第三章 设计计算书 7

3.1设计参数 7

3.2除湿过程分析计算 7

3.3制冷循环热力平衡计算 8

3.4压缩机选型及实际负荷计算 10

3.5蒸发器计算 11

3.5.1翅片管簇选择计算 11

3.5.2总传热系数的计算 13

3.5.3确定蒸发器结构尺寸 19

3.5.4 蒸发器主要参数汇总 21

3.6冷凝器的计算 22

3.6.1翅片管簇选择计算 22

3.6.2 相关温度的计算及其物性参数 24

3.6.3 传热计算 24

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