论文总字数：31768字

摘 要

空气调节，自其问世以来，一开始主要是着重对温度进行控制和调节，而对湿度的控制相对较少。然而在科学技术迅猛发展的今天，除湿能耗已经占到空气调节总能耗的20%，空气调节中除湿在某些特定场合，如档案库房、生产车间、人防工程和国防工程等有严格的要求，对人体生活环境的舒适性也有着举足轻重的影响。我国大部分地区属于亚热带气候，特别是长江流域及以南地区，空气相对比较潮湿，对除湿技术的需求尤为突出。

空气的除湿方法有多种，空调工程中常用的空气除湿技术有：冷冻除湿、压缩除湿、热管除湿、转轮除湿和溶液除湿等。本论文中介绍的组合式风道除湿机采用冷冻除湿技术。冷冻除湿由于能耗小、操作简单、易于控制，得到了广泛的应用。

本论文主要介绍了组合式风道除湿机的工作原理以及主要的结构组成，对冷冻除湿技术的常见故障做了相应的分析，并简单介绍了目前国内的现状和发展改进方向。本论文中的风道除湿机采用冷冻除湿技术，其原理是用制冷机做冷源，以直接蒸发式冷却器作冷却设备，把空气冷却到露点温度以下，析出大于饱和含湿量的水汽，降低空气的绝对含湿量，再利用部分或全部冷凝热加热冷却后的空气，从而降低空气的相对湿度，达到除湿的目的。该除湿机主要部件有蒸发器、冷凝器、压缩机、膨胀阀和风机，按结构与功能可分为三大系统：制冷循环系统、空气循环系统和电气控制系统。在制冷系统中，由压缩机压缩出来的高温、高压制冷剂气体进入风冷冷凝器，将热量传给空气和冷却水，冷凝成常温高压制冷剂液体。冷凝后的制冷剂液体经节流阀节流后进入蒸发器，吸收空气中的热量蒸发成低温低压的气体，进入压缩机压缩，如此往复循环。在送风系统中，湿空气经过过滤器被吸入后，在蒸发器内被冷却到机器露点温度以下，析出冷凝水。然后在进入风冷冷凝器中吸收冷凝热升温，降低空气的相对湿度。而电气系统就是控制电源的开关，让压缩机和风机同时工作。

本论文介绍的是一台25kg/h的组合式风道除湿机的设计。本课题的研究采用理论计算，根据给定的的初始条件计算出系统热负荷，确定压缩机。然后进行热平衡计算和制冷循环计算，确定各部分的热负荷，从而确定冷凝器、蒸发器负荷及进、出口温度，然后进行蒸发器和风冷冷凝器的结构设计以确定其结构。最后对蒸发器和冷凝器进行传热计算和阻力压降计算和校核。

本课题在设计中着重考虑了蒸发器和冷凝器的强化传热问题。由于空气侧的换热系数很低，对整体换热系数的影响很大，所以在设计时，换热管采用正三角排列并在管外采用整体套片式肋片，以强化空气侧换热，从而提高整体换热系数，减小换热器的结构尺寸。考虑到蒸发器翅片上会有大量水蒸气凝结，蒸发器翅片采用清水膜处理，便于凝结水的流出。

关键词：除湿机 蒸发器 冷凝器 压缩机

The design of 25kg/h combined air duct dehumidifier

Abstract

Since its inception, the air conditioning has been mainly focused on the temperature control and regulation, while the control of humidity was relatively less. However, the energy consumption of dehumidification has accounted for 20% of total energy consumption with the rapid development of science and technology today.In certain situations, such as archives warehouse, production workshop,civil defence fortifications and National Defence Engineering,there are strict requirements for dehumidified. Air dehumidification also has a significant impact on comfortable living environment for the human body. A majority of areas in our country belong to subtropical climate. Especially, at Yangtze Valley and in south area of it, the relative humidity of the air is relatively high. Therefore, in these areas, the demand of dehumidifying technology is particularly outstanding.

There are several methods of air dehumidification. Air dehumidifying technology commonly used in air conditioning projects are: frozen dehumidification, compressed dehumidification, heat pipe dehumidification, desiccant wheel dehumidification, liquid desiccant, etc. The combined air duct dehumidifier introduced in this paper uses frozen dehumidification technology. Due to the low energy consumption, simplified operation and easy to control, frozen dehumidification has been widely used.

The working principle and the main components of the combined air duct dehumidifier are described in the thesis.And the common faults and solutions, and the status and improvement of frozen dehumidification at home and abroad are also described in the thesis. The combined air duct dehumidifier introduced in this paper uses frozen dehumidification technology. The principle of it is that by lowing the temperature of wet air below the apparatus dew-point temperature, most air is precipitated condensed water. The main components of combined air duct dehumidifier are evaporator, air-cooled condenser, compressor, expansion valve, fans and so on. Air dehumidification machine according to the structure and function can be divided into three parts: refrigeration system, air supply system, and electrical control system. In refrigeration system, the high temperature and high pressure refrigerant gas which is compressed by a compressor is pumped into condenser with air-cooled condenser. The heat passed to air and cooling water and the gas is condensed into high-pressure liquid. Then the high-pressure liquid is pumped into the evaporator after being throttled by expansion valve. It evaporates into the low temperature and low pressure gas by absorbing the heat from air. Then it is sucked into the compressor for compression, and the cycle is repeated again and again. In the air supply system, the wet air sucked into the evaporator after being filtered is cooled below the apparatus dew-point temperature, and precipitated condensed water. Then the low-temperature air is pumped into air-cooled condenser absorbing condensing heat to rise the temperature. The function of electrical control system is to control the the power switch to make compressor and fans to start work at the same time.

The design of an 25kg/h combined air duct dehumidifier is described in the paper. This topic research method is theoretical calculation. Based on the given initial conditions to calculate the heat load of the system and determine the compressor. Then start the heat balance and refrigeration cycle calculations to determine the thermal load of each part to determine the load , inlet and outlet temperature of condenser and evaporator. Next we can design the air-cooled condenser and evaporator and determine its structure. Finally, we conduct the heat transfer calculation , resistance calculation and the check of the heat exchanger.

The problems of strengthening of the evaporator and condenser heat transfer were considered seriously in the design of dehumidifier. Due to the air side heat transfer coefficient is very low and had a great influence on integrated heat transfer coefficient, the heat exchange tubes used in the design are triangular arrangement and increase the outside whole set of fins to strengthen the air-side heat transfer,improve the whole heat transfer coefficient, and decrease the structure size of heat exchanger. Considering that there will be a large number of water vapor condensation on the evaporator fin, evaporator fin carry on the membrane treatment to facilitate the condensate flow out.

Key words: dehumidifier evaporator condenser compressor

目录

摘要 Ⅰ

Abstract III

目录 1

第一章 绪论 3

1.1组合式风道除湿机的工作原理 3

1.2组合式风道除湿机的结构特点 4

1.3组合式风道除湿机常见故障及解决方法 6

1.4组合式风道除湿机的发展与改进 7

1.5冷冻极限除湿系统 8

1.6本课题研究的相关内容及意义 9

第二章 设计计算说明 10

2.1原始数据参数 10

2.2 制冷循环的计算 10

2.2.1湿空气计算 10

2.2.2理想单级压缩制冷循环的计算 11

2.2.3压缩机选型 13

2.3 制冷循环系统 14

2.3.1制冷循环系统的基本流程 14

2.3.2实际单级压缩制冷循环的设计计算………………………15

2.3.3最佳风量的确定……………………………………………17

2.4蒸发器的设计计算 17

2.4.1确定蒸发器进口与出口空气状态参数……………………18

2.4.2蒸发器结构参数的确定……………………………………18

2.4.3蒸发器的设计计算…………………………………………18

2.5风冷冷凝器的设计计算 29

2.5.1制冷循环系统计算…………………………………………29

2.5.2风冷冷凝器的风冷冷凝器的结构…………………………29

2.5.3风冷冷凝器的设计计算……………………………………30

2.6组合式风道除湿机主要换热器的结构参数…………………...38

结语……………….………………………………………………...40

参考文献……………………………………………………………41

致谢…………………………………………………………………43

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