Abstract:

The paper introduces the design principle and experimental prototype structure of an external cooling solution dehumidifier based on evaporative cooling. By using the LiCl and CaCl₂ solution as liquid desiccant and taking the dehumidification rate and corresponding dehumidification air outlet temperature as evaluation indexes, the dehumidification performance difference of LiCl and CaCl₂ solutions under externally evaporative cooling conditions are analyzed and compared through a series of experiments. The results show that the dehumidification performance of LiCl solution with 0.35 mass ratio is similar to that of CaCl₂ solution with 0.45 mass ratio, whose dehumidification rate and corresponding air outlet temperature are both higher than CaCl₂ solution with 0.35 mass ratio. Moreover, the dehumidification rate of LiCl solution with 0.35 mass ratio is about 73% higher than that of CaCl₂ solution with 0.35 mass ratio, and the larger air flow rate leads to a greater dehumidification rate difference. In addition, the increase of evaporative cooling air flow rate can not only increase the dehumidification rate, but also reduce the corresponding air outlet temperature by about 1.4℃. The effect of the spray water temperature on the dehumidification performance of CaCl₂ solution is more obvious than that of LiCl solution. The research results provide a reference for the practical application of this kind of externally cooled dehumidifier.

Key words: aqueous solution, heat/mass transfer, experimental validation, evaporative cooling, dehumidification

摘要：

介绍了一种基于蒸发冷却的外冷型溶液除湿装置设计原理及实验样机结构。分别以LiCl和CaCl₂溶液为除湿剂，以除湿率和除湿空气出口温度为评价指标，通过实验对比分析了LiCl和CaCl₂在蒸发冷却条件下的除湿性能差异。结果表明：在所有实验条件下，浓度为0.35的LiCl溶液与浓度为0.45的CaCl₂溶液除湿性能相似，其除湿率与对应空气出口温度均高于浓度为0.35的CaCl₂溶液；浓度为0.35的LiCl溶液比浓度为0.35的CaCl₂溶液的除湿率要约提高73%，并且空气流量越大其绝对提高值越大。另外，蒸发冷却空气流量增加除使除湿率增加外还会降低空气出口温度，约1.4℃；改变喷淋水温度对CaCl₂溶液除湿性能的影响比对LiCl溶液更为明显。研究结果为该种外冷型溶液除湿器的实际应用提供参考。

关键词: 水溶液, 传热传质, 实验验证, 蒸发冷却, 除湿