【作者】 段满清；

【导师】 邹声华； 李孔清；

【作者基本信息】 湖南科技大学 ， 供热、供燃气、通风及空调工程， 2008， 硕士

【摘要】 随着人类社会的进步,人们的生活水平不断提高,空调成了人们生产和生活的必需。但随着空调设备的不断普及,人类社会也面临了一系列新的问题。空调在给人们提供舒适的生活和工作环境的同时,又消耗了大量的能源,造成能源紧张;传统机械制冷所使用的制冷剂一旦泄露到大气中,会破坏臭氧层,从而加速温室效应的形成;2003年SARS疫情的爆发,也使人们对空调系统的安全问题引起了关注。直接蒸发冷却空调利用水的蒸发取得能量,与机械制冷相比,蒸发冷却制冷不需要消耗压缩功,同时,它以天然水作为制冷剂,对大气环境无污染。蒸发冷却是一种集节能、环保、健康于一体的空调方式,从而受到暖通界人士的青睐。本论文以直接蒸发冷却器为研究对象,借助传热传质学、流体力学、空气动力学及其它相关理论,采用计算机仿真技术和实验手段,从直接蒸发冷却器的结构、传热传质机理及影响直接蒸发冷却器工作性能的主要因素等多个方面对直接蒸发冷却器进行了系统综合的研究。(1)通过对直接蒸发冷却器的传热传质机理的分析和对直接蒸发冷却过程的热工性能进行计算后,得出直接蒸发冷却器工作性能的主要影响因素。(2)在分析直接蒸发冷却器冷却过程特性的基础上,根据传热传质学、流体力学、空气动力学等相关基础理论,建立直接蒸发冷却器的数学模型。选用CFD商用软件FLUENT对直接蒸发冷却过程进行数值计算,并通过现场测试,得出了填料厚度、迎面风速、入口空气干湿球温度及相对湿度对直接蒸发冷却器工作性能的影响规律:填料厚度和迎面风速能够直接影响到直接蒸发冷却器的工作性能,温降、加湿量以及冷却效率都会随着填料厚度的增加(迎面风速的降低)而增大;而入口空气干湿球温度以及相对湿度的变化对直接蒸发冷却器的冷却效率无多大影响,但被处理空气的温降和加湿量会随着干湿球温度差的增加而增大。(3)为了拓宽直接蒸发冷却技术的应用范围,本文对直接蒸发冷却技术在新风预处理中的应用和多级蒸发冷却空调方式进行了系统分析。构建了溶液除湿蒸发冷却系统,介绍了溶液除湿与再生过程,提出了溶液除湿蒸发冷却系统的几种模式,通过分析得出:新风先除湿再与回风混合比新回风混合后再除湿更加节能;将室内排风作为溶液再生器中的再生空气,既加强对处理空气的预冷,回收了排风的冷量,同时又提高再生器的效率,降低了系统能耗。更多还原

【Abstract】 With the development of human society, people’s standard of living improves unceasingly, and the air conditionings become a necessity for people’s living. But with the popularity of air-conditioning, human society faces new challenges. While the air conditionings give us comfortable life and working conditions, it also consumes massive energy. The refrigerating medium used for the traditional machinery refrigeration leaking into the atmosphere, will destroy the ozone layer, and accelerate the formation of green house effect; The outbreak of SARS in 2003, also aroused people’s concern to the safety of air-conditioning systems. Direct evaporating cooling air-conditioning acquires energy from water evaporation. Comparing with mechanical refrigeration, it does not need work done during compression. Using water as refrigerating medium, it doesn’t pollute the environment. Direct evaporative cooling is an air-conditioning mode taking advantage of energy-saving, environmental protection and health, and got the favor of HVAC.This paper researches the direct evaporative cooling air-conditioning , using of heat and mass transfer theories, hydrodynamics, aerodynamics, and other related theories, adopting analogue experiment means and the computer simulation technology. The structure of direct evaporative cool air-conditioning, mechanism of heat and mass transfer, and the major factors impact of direct evaporative cooler performance are synthetically studied in this paper.(1)With the theoretical analysis and calculation of direct evaporative cooling air-conditioning of heat and mass transfer, the relationship between cooling efficiency and its influencing factors are studied.(2) Analyzing characteristic property of direct evaporative cooling, according to heat and mass transfer theory, hydromechanics, aerodynamics, and other relevance theories, structure mathematic model of direct evaporative cooling air-conditioning is established, Selecting and using CFD commercial software FLUENT, the direct evaporative cooling process is simulated. With numerical simulation and experiment research, different conditions are made by changing filler thickness, air velocity and the states of air inlet. Filler thickness and air velocity can directly affect the evaporative cooling work performance. Temperature drop and cooling efficiency will increase as the filler thickness (air velocity reducing) increasing. Dry-bulb temperature, wet-bulb temperature and relative humidity have little impact in the direct evaporative cooling efficiency, but temperature drop and psychometric difference will increase as the dry-bulb and wet bulb temperature difference increasing.(3)In order to broaden the application of direct evaporative cooling, this paper analyses the application of direct evaporative cooling in fresh air pretreatment and multi-stage evaporative cooling. This paper constructs liquid desiccant evaporative cooling systems, introduces liquor desiccant and regeneration process, propose several models of desiccant evaporative cooling systems. The results show: fresh air desiccated before mixed with return air should save more energy than reverse procedure. Using return air indoor as renewable air, which not only strengthen the pre-cooling of air, recycling the energy of return air, but also improve the efficiency of regeneration, and lower energy consumption.更多还原