【作者】 李献偶；

【导师】 李勇；

【作者基本信息】 上海交通大学 ， 供热、供燃气、通风及空调工程， 2011， 硕士

【摘要】 干燥剂除湿换热器作为一种内冷/热式除湿器,以换热器为基材,具有较好的传热性能,与一般的绝热式除湿床相比,可同时实现对再生和除湿过程的强化。同时,该除湿器可以使用太阳能等可再生能源作为驱动热源,具有良好的节能效应。为了对这类除湿换热器的运行特点进行更深入的研究,本文以除湿换热器作为研究对象之一,从实验测试和理论模拟两个角度进行了探讨。论文建立了太阳能热水驱动除湿换热器的实验装置,从理论和实验两个方面对除湿换热器进行了研究分析。结果表明,通过控制再生时间和送风起始点,可以降低能耗和获得最佳的送风状态;太阳能热水驱动除湿可以实现全天平均除湿量0.1g/s、平均制冷量552W;且使用多台除湿器切换运行,可实现在连续除湿的同时,将除湿量和制冷量翻倍。论文对除湿换热器的传热传质数学模型进行了补充修改,增加了反应冷热对冲过程的附加方程,对原模型的模拟结果进行了改善。利用该数学模型,对若干运行参数的影响进行分析,推导了除湿换热器传热和传质单元数的表达式。模拟结果表明,在ARI夏季工况下,再生热水和冷却水的温度对除湿性能有很大的影响;对处理空气进行除湿前预冷和再生前预热对性能的影响有限;随着气侧传热和传质单元数的增加,系统的除湿率和全热换热率逐渐增加。另外,使用搭建的除湿换热器在上海冬季工况下可以实现平均加湿量0.107g/s。研究结果表明再生式除湿换热器再生效果好,除湿效率高,可以利用太阳能等可再生能源,具有很好的应用前景。作为对另一种强化除湿方法的探索,本文通过实验测定了磁场对硅胶和LiCl-硅胶复合干燥剂吸附性能的影响,并对其应用于除湿过程的潜力进行了分析。实验结果表明:在试验工况下,磁场可以在一定程度上降低硅胶的吸附量,对吸附具有抑制作用。更多还原

【Abstract】 Desiccant-coated heat exchanger (DCHE) is a kind of internal cooled/heated dehumidifier, which is made by fin-tube heat exchanger coated with solid desiccant materials. Compared with conventional adiabatic dehumidifier, DCHE can overcome the decrease of dehumidification cased by adsorption heat and the decrease of regeneration cased by desorption heat, which in turn enhances the dehumidification and regeneration respectively. The media used to regenerate the desiccant is hot water, so solar energy and other low grade thermal energy can be used. In this paper, DCHE is experimentally and theoretically investigated.An experimental setup is build to test the performance of DCHE driven by solar water. It is found that the energy consumed can be reduced and proper supply air conditions can be reached by controlling the regeneration time and the supply points respectively. According to the test results of several typical conditions in a whole day, the average moisture removal rate and average cooling capacity are predicted and they could be tripled by using three devices at the same time.A one-dimensional heat and mass transfer model of DCHE is used to analyze the effects of several parameters on system performance in terms of dynamic air outlet humidity ratio as well as temperature. In order to describe the phase between two operation modes, in which hot and cold water blend together, two equations are added to the original model. At the same time, the fundamental dimensionless groups like the number of transfer units were derived. The simulation results conclude that the temperature of water affects greatly the dehumidification performance. While in comparison with the effects caused by water temperature, air temperature affects less. In this paper, the humidification function of DCHE in winter is also predicted. The simulation results based on typical meteorological parameters of Shanghai shows that DCHE can provide humidification and heating rate 0.107g/s, when the hot water temperature is 70℃.As an attempt to utilize the magnetic fields in the desiccant cooling system, the influences of magnetic fields on the adsorption of water on silica gel and composite desiccant are investigated. Results show that under given conditions, the magnetic fields can reduce the adsorption amount to some extent.更多还原