基于扩散吸收式制冷的文物展柜恒湿环境控制研究
发布时间：2018-07-16 15:45
【摘要】：随着国家对文物保护事业的日益重视以及空气调节技术、控制技术的渐趋成熟,为了使珍贵的文物得到更好的保护,大量馆藏文物的保存环境亟需改善。影响文物能否长久保存的主要环境因素有相对湿度、温度、光照强度和有害气体浓度等,其中的相对湿度是最基本、最重要的因素,因此为文物提供恒湿的保存环境至关重要。对于博物馆中的小型独立展柜,其有体积较小、分布灵活、可移动的特点,故不宜采用大型集中式空气处理机组控制相对湿度。目前,国内外不少文物保护机构已专门为小型独立展柜研制出了主动式恒湿环境控制设备,其中绝大多数是基于半导体制冷,该种设备具有工作无噪音、占空间小的优点,但存在冷量低、易结垢的缺点。针对此缺点并兼顾其优点,为研制出一种适用于小型独立展柜的新型恒湿环境控制系统,本文主要开展了以下三方面工作:(1)为了满足博物馆对安静环境的要求,采用具有工作稳定、运行无噪音等优点的扩散吸收式制冷机作冷源,利用PLC模块作为控制器。将蒸发管置于水中,依据空气与不同温度的水面直接接触时有不同的状态变化过程原理,把加湿、除湿过程结合在一起,通过控制水温来间接控制湿度,成功设计了一种结构紧凑的湿度控制系统。(2)为了确定控制风机的方式,最佳的发生器加热功率以及恰当的PLC控制方法首先开展了初步实验,依据实验结果得出控制风机的最佳方法为当达到程序设定命令时使其保持常开,最佳的加热功率范围为37W-80W,PLC宜采用PID模拟量输出控制。接着对展柜内相对湿度控制开展了实验研究,实验结果表明该湿度控制系统可使展柜内相对湿度在45%～65%之间连续可调并保持恒湿状态,控制偏差均在允许范围内,最大控制偏差在士1.25%以内,完全满足不同文物保存时对湿度环境差异性的要求。(3)为了研究提高空气与水直接接触时的热湿交换效率的方法,以加快湿度控制系统的动态响应,完善湿度控制系统的性能,借助数值模拟的方法对其进行了探究。在深入分析了直接接触式传热传质机理的基础上建立了简化的CFD模型,采用ANSYS Fluent对简化的模型在稳态工况下的传热传质进行了数值计算,并将计算结果同实验值和关联式进行了对比验证,结果证实了简化模型的合理性与有效性。利用该模型对三种不同结构水箱中的空气处理过程进行了数值模拟分析,结果显示采用上送上回的空气处理方式具有最高的传热传质效率,为优化空气处理过程提供了指导方向。
[Abstract]:With the increasing attention paid by the state to the protection of cultural relics and the development of air conditioning technology and control technology, in order to better protect the precious cultural relics, the preservation environment of a large number of cultural relics is in urgent need of improvement. The main environmental factors affecting the preservation of cultural relics for a long time are relative humidity, temperature, intensity of light and concentration of harmful gases, among which the relative humidity is the most basic and important factor, so it is very important to provide a constant humidity environment for cultural relics. For the small independent display cabinets in the museum, they have the characteristics of small volume, flexible distribution and movable, so it is not suitable to use a large centralized air treatment unit to control relative humidity. At present, many cultural relics conservation organizations at home and abroad have specially developed active constant humidity environment control equipment for small independent display cabinets, most of which are based on semiconductor refrigeration. This kind of equipment has the advantages of no noise at work and small space. But has the cold quantity low, easy to form the scale the shortcoming. Aiming at this shortcoming and taking into account its advantages, in order to develop a new type of constant humidity environment control system suitable for small independent display cabinets, this paper mainly carried out the following three aspects of work: (1) in order to meet the requirements of the museum for the quiet environment, The diffusive absorption chiller which has the advantages of stable operation and no noise is used as the cold source and PLC module is used as the controller. The evaporation pipe is placed in water. According to the principle of different state change process when air is in direct contact with the water surface at different temperature, the humidification and dehumidification process are combined together, and the humidity is indirectly controlled by controlling the water temperature. A compact humidity control system is successfully designed. (2) in order to determine the control mode of the fan, the optimal heating power of the generator and the proper PLC control method are first carried out preliminary experiments. According to the experimental results, the best way to control the fan is to keep it on when the program set command is reached, and the optimal heating power range is 37W-80WN PLC, which should be controlled by pid analog output. The experimental results show that the relative humidity in the display cabinet can be adjusted continuously between 45% and 65%, and the control deviation is within the allowable range, and the relative humidity control in the display cabinet has been studied experimentally, and the experimental results show that the relative humidity in the display cabinet can be adjusted continuously between 45% and 65%, and the control deviation is within the allowable range. The maximum control deviation is less than 1.25%, which fully meets the requirement of the difference of humidity environment when different cultural relics are preserved. (3) in order to study the method to improve the efficiency of heat and humidity exchange when air and water are in direct contact, the dynamic response of humidity control system is accelerated. Improve the performance of humidity control system, with the help of numerical simulation method to explore it. A simplified CFD model is established on the basis of analyzing the mechanism of direct contact heat and mass transfer, and the numerical calculation of heat and mass transfer of the simplified model under steady condition is carried out by using ANSYS fluent. The calculated results are compared with the experimental data and the correlation formula. The results show that the simplified model is reasonable and effective. The model is used to simulate the air treatment process in three kinds of water tanks with different structures. The results show that the air treatment with upward return has the highest heat and mass transfer efficiency. It provides guidance for optimizing air treatment process.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB65
[Abstract]:With the increasing attention paid by the state to the protection of cultural relics and the development of air conditioning technology and control technology, in order to better protect the precious cultural relics, the preservation environment of a large number of cultural relics is in urgent need of improvement. The main environmental factors affecting the preservation of cultural relics for a long time are relative humidity, temperature, intensity of light and concentration of harmful gases, among which the relative humidity is the most basic and important factor, so it is very important to provide a constant humidity environment for cultural relics. For the small independent display cabinets in the museum, they have the characteristics of small volume, flexible distribution and movable, so it is not suitable to use a large centralized air treatment unit to control relative humidity. At present, many cultural relics conservation organizations at home and abroad have specially developed active constant humidity environment control equipment for small independent display cabinets, most of which are based on semiconductor refrigeration. This kind of equipment has the advantages of no noise at work and small space. But has the cold quantity low, easy to form the scale the shortcoming. Aiming at this shortcoming and taking into account its advantages, in order to develop a new type of constant humidity environment control system suitable for small independent display cabinets, this paper mainly carried out the following three aspects of work: (1) in order to meet the requirements of the museum for the quiet environment, The diffusive absorption chiller which has the advantages of stable operation and no noise is used as the cold source and PLC module is used as the controller. The evaporation pipe is placed in water. According to the principle of different state change process when air is in direct contact with the water surface at different temperature, the humidification and dehumidification process are combined together, and the humidity is indirectly controlled by controlling the water temperature. A compact humidity control system is successfully designed. (2) in order to determine the control mode of the fan, the optimal heating power of the generator and the proper PLC control method are first carried out preliminary experiments. According to the experimental results, the best way to control the fan is to keep it on when the program set command is reached, and the optimal heating power range is 37W-80WN PLC, which should be controlled by pid analog output. The experimental results show that the relative humidity in the display cabinet can be adjusted continuously between 45% and 65%, and the control deviation is within the allowable range, and the relative humidity control in the display cabinet has been studied experimentally, and the experimental results show that the relative humidity in the display cabinet can be adjusted continuously between 45% and 65%, and the control deviation is within the allowable range. The maximum control deviation is less than 1.25%, which fully meets the requirement of the difference of humidity environment when different cultural relics are preserved. (3) in order to study the method to improve the efficiency of heat and humidity exchange when air and water are in direct contact, the dynamic response of humidity control system is accelerated. Improve the performance of humidity control system, with the help of numerical simulation method to explore it. A simplified CFD model is established on the basis of analyzing the mechanism of direct contact heat and mass transfer, and the numerical calculation of heat and mass transfer of the simplified model under steady condition is carried out by using ANSYS fluent. The calculated results are compared with the experimental data and the correlation formula. The results show that the simplified model is reasonable and effective. The model is used to simulate the air treatment process in three kinds of water tanks with different structures. The results show that the air treatment with upward return has the highest heat and mass transfer efficiency. It provides guidance for optimizing air treatment process.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB65
【参考文献】
相关期刊论文 前10条
1 王恒旭;张学军;郑幼明;段兵兵;;扩散吸收式恒湿文物展柜实验研究[J];低温工程;2016年01期
2 张学军;郑幼明;王恒旭;孙大明;李s，
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