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建筑热湿环境营造过程中换热网络的匹配特性分析 总被引:5,自引:4,他引:1
对主动式空调系统中的换热网络进行研究,分析了匹配特性在显热传递和热湿传递过程中的影响.显热传递过程由于传热能力UA有限和两侧流体流量不匹配会造成损失,热湿传递过程的损失则是由传热传质能力有限、流量不匹配和参数不匹配3种因素共同造成的.流量匹配的条件是两侧流体的热容量相等,空气与水直接接触的热湿传递过程只有在饱和线上进行时才能实现参数匹配.利用解析方法得到热湿传递过程中的传热阻力、传湿阻力表达式,分析了传热传质能力有限、流量不匹配和参数不匹配对热阻、湿阻造成的影响. 相似文献
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使用耐腐蚀的10PPI氧化铝(Al2O3)陶瓷泡沫作为溶液除湿填料并对其进行了实验研究.采用氯化锂的水溶液作为除湿剂.实验在人工环境舱中进行,研究了在溶液和空气处于逆流的情况下,进口空气流量、干球温度、含湿量以及进口溶液温度、浓度、流量对除湿量和除湿效率的影响.除湿效率和除湿量最高分别可以达到62.69%和0.819g/s.进口空气流量、含湿量,进口溶液流量、浓度的增加对除湿量增加起促进作用,但是进口空气干球温度、进口溶液温度的增加时除湿量是减少的.进口空气流量、干球温度以及进口溶液温度的逐渐增加时,除湿效率呈现下降趋势.进口溶液浓度对除湿效率的影响很小.利用实验结果拟合出了除湿效率和除湿量的表达式. 相似文献
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多孔建筑材料热湿传递过程的研究 总被引:6,自引:0,他引:6
从理论计算和实验研究等方面对国内外多孔建筑材料的传热、传湿及热湿耦合传递研究方面的进展进行了综合分析。指出了目前多孔建筑材料热湿传递过程研究中存在的问题,并对未来的研究方向进行了展望。 相似文献
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Packed-bed heat and mass transfer devices are widely used in air-conditioning systems, such as cooling tower, evaporative cooler of air–water direct-contact devices, dehumidifier and regenerator of air–liquid desiccant direct-contact devices. Similarities of heat and mass transfer characteristics between air–water and air–liquid desiccant devices are considered and investigated in this paper. Same reachable handling region of outlet air can be obtained for both air–water and air–liquid desiccant devices, which is among three boundary lines, isenthalpic line of inlet air, iso-relative humidity line of inlet fluid (water or desiccant), and the connecting line of inlet statuses of air and fluid. Inlet conditions of air and fluid affect heat and mass transfer characteristics to some extent, so that a zonal method is proposed only according to the relative statuses of inlet air to inlet fluid. Four zones, dehumidification zones A, D and regeneration zones B, C, are divided for air-desiccant direct-contact devices. The first three zones A, B and C are divided for air–water direct-contact devices, with the same zonal properties as those of air-desiccant devices. In order to obtain better humidification performance, fluid should be heated (in zone C) rather than air (in zone B). And fluid should be cooled (in zone A) rather than air (in zone D) to obtain better dehumidification performance. Counter-flow pattern should be applied for best mass transfer performance in the same conditions within the recommended zone A or C, while parallel-flow pattern is the best in zone B or D. 相似文献
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A new type of air conditioning system, the liquid desiccant evaporation cooling air conditioning system (LDCS) is introduced in this paper. Desiccant evaporation cooling technology is environmental friendly and can be used to condition the indoor environment of buildings. Unlike conventional air conditioning systems, the system can be driven by low-grade heat sources such as solar energy and industrial waste heat with temperatures between 60 and 80 °C. In this paper, a LDCS, as well as a packed tower for the regenerator and dehumidifier is described. The effects of heating source temperature, air temperature and humidity, desiccant solution temperature and desiccant solution concentration on the rates of dehumidification and regeneration are discussed. Based on the experimental results, mass transfer coefficients of the regeneration process were experimentally obtained. The results showed that the mean mass transfer coefficient of the packing regenerator was 4 g/(m2 s). In the experiments of dehumidification, it was found that there was maximal tower efficiency with the suitable inlet humidity of the indoor air. The effective curves of heating temperature on the outlet parameters of the regenerator were obtained. The relationships of regeneration mass transfer coefficient as a function of heating temperature and desiccant concentration are introduced. 相似文献
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