论文总字数：25483字

摘 要

随着我国经济的快速发展，我们对能源的需求量越来越大，因此要实现经济的可持续性发展，最关键的是要解决能源问题。其中，空气能是一种广泛存在、平等给予并且可自由利用的低品味能源，我们可利用热泵循环来提高其能源品味，所以是一项极具开发和应用潜力的节能、环保新技术。

热泵是一种利用高位能使热量从低位热源流向高位热源的装置。如水泵利用电能将低位水源里的水泵送到高位水泵里一样。在各种获取热量的装置中，热泵是一种节能的装置。空气源热泵机组则是应用逆卡诺循环原理，通过热泵系统(压缩机、蒸发器、膨胀阀、冷凝器)，吸取空气中的能量并转移到水中，使初始冷水多次流过热泵热水器内的换热器逐渐达到设定温度。

由于空气源热泵热水器在使用中会受到环境温度，进水温度，组成部件性能等的影响，所以国内外的诸多学者已经对空气源热泵热水器进行了系统结构的研究。主要包括换热器结构的研究、节流机构的研究和压缩机的研究。其中，换热器的研究是相对而言比较重要的。

循环式空气源热泵系统的特点主要有控制系统简单，运行可靠，故障率低，一般只需温控器控制水温就可安全运行；加热水箱存储了一定量的热水，供热水量主要由容积大小决定，在短时间内能为用户提供大量热水；由于一般情况下循环水箱的水温在50~55℃之间，所以压缩机的运行条件不好；在循环加热过程中，随着加热水箱中的水温逐渐升高，水温的增长速度却逐渐降低。

空气源热泵热水器与燃气热水器等其他热水器相比较，它们的节能效果如下：煤气热水器的一次能源热效率较低；电热水器的热效率虽高但电热水器的一次能源热转换效率很低，即一次能源的发电效率很低；电辅助太阳能热水器，天然气和LPG热水器具有较高的一次能源热效率或能效但没有空气源热泵热水器具有的能效高。因此，空气源热泵热水器具有最高的能效。

在整个循环式空气源热泵热水器的设计计算过程中，先要进行压缩机的选型，在进行热力计算，热力计算主要包括温差、传热系数和换热面积等的计算，这部分内容适合各种类型的热泵系统。其次是结构设计，它主要包括热泵系统的蒸发器和冷凝器的设计。本系统的蒸发器是采用直接蒸发式空气冷却器，冷凝器是采用套管式。最后还要设计膨胀阀，本系统采用热力膨胀阀。

设计包含了技术说明和设计图纸。

关键词：空气源 直接蒸发式空气冷却器 热泵 套管式

Design of circulating air-source heat pump water heater

Abstract

With the rapid development of economy in our country and the demand for energy is growing. In order to realize the sustainable development of economy, the key is to solve the energy problem. Air energy is a kind of widespread, giving equal and free to use low-grade energy, using heat pump cycle to improve its energy taste. So it is a great development and potential applications of new technology of energy saving and environmental protection.

Heat pump is a kind of making heat flow from low heat source to high heat source device, using high potential-energy. Like a water pump make the water pump in low water into high water pump by using electric energy. In a variety of devices for heat, heat pump is a kind of energy-saving device. Air-source heat pump units is applied reverse carnot cycle principle, through the heat pump system, including compressor, evaporator, expansion valve, condenser, absorbs energy in the air and then transfers it to the water to make initial cold water reach the set temperature gradually by flowing through heat exchanger in the heat pump water heater several times.

Because of the air source heat pump water heater will be affected by environmental temperature, inlet temperature and the performance of components in use, many scholars at home and abroad has been on the structure of air source heat pump water heater system research. The research mainly includes the studies of heat exchanger structure, throttle body and compressor. In contrast, the study of the heat exchanger is important.

The main characteristics of the circulating air source heat pump system are simple control system, reliable operation and low failure rate. It can run safely as long as the thermostat control water temperature normally. Because the heating-water tank store a certain amount of hot water and the amount of hot water provided to the users is mainly determined by the volume size, it can provide users with a large amount of hot water in a short time. As a general rule, the water temperature in

circulating water tank is between 50 to 55 ℃. It has a bad effect on the operating conditions of a compressor. In the process of cyclic heating, as the water temperature of the heating-water tank is increased, the growth rate of water temperature is gradually reduced.

Comparing air-source heat pump water heater with gas water heater and other water heaters, their energy-saving effect as follows. The primary energy thermal efficiency of gas water heater is low; Electric water heater’s thermal efficiency is high but the heat energy conversion efficiency of electric water heater is low, namely primary energy efficiency is very low; Although electric auxiliary solar water heater, natural gas and LPG water heater has higher thermal efficiency of primary energy and energy efficiency, they are all lower than the efficiency of air- source heat pump water heater. As a result, the air-source heat pump water heater has the highest energy efficiency.

The thermal calculation is the primary factor in the circulating air source heat pump water heater design calculations, which includes the selection of compressor, thermodynamic calculation and the structure design. Thermodynamic calculation mainly includs the calculations of temperature, heat transfer coefficient and heat transfer area, all of these calculation suit to various different heat pump system. The design of structure mainly includes the design of the heat pump system of the evaporator and condenser. The evaporator of this system is to use direct evaporative air cooler and the condenser of this system is to use double pipe condenser. Finally, about designing expansion valve , the system adopts thermal expansion valve.

The design includes technical note and design drawings.

Key words: Air source；Direct evaporative air cooler；Heat pump；Tube-in-tube style

目 录

摘要 I

Abstract III

第一章 绪论 1

1.1课题背景 1

1.2空气源热泵概述 2

1.2.1循环式空气源热泵热水器的工作原理 2

1.2.2空气源热泵系统的结构 2

1.2.3循环式空气源热泵热水器的特点 3

1.3空气源热泵热水器能效分析与选用 5

1.4空气源热泵热水器的应用与展望 5

第二章 5匹循环式空气源热泵热水器的设计步骤 7

2.1热力计算的内容 7

2.2压缩机的选取 7

2.3蒸发器的计算步骤 7

2.4冷凝器的计算步骤 8

2.5节流阀的选取 8

2.6水箱的设计 8

第三章 5匹循环式空气源热泵热水器的设计 9

3.1任务要求 9

3.2原始数据参数 9

3.3系统设计 10

3.3.1压缩机的选择 10

3.3.2工况确定 11

3.3.3 制冷循环热力状态参数 12

3.4设计计算 13

3.4.1热泵系统热力计算 13

3.4.2直接蒸发式空气冷却器的设计计算 15

3.4.3 套管式冷凝器的设计计算 23

3.4.4 膨胀阀的选择 27

3.4.5 水箱的设计 30

3.4.6 风机的选择 31

结束语 33

参考文献 34

致谢 37

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