不同固態除濕劑塗佈熱交換器除濕系統之吸濕效率研究

Hygroscopic Efficiency Analysis of Desiccant Coating Heat Exchangers with Different Solid Desiccants

本研究以矽膠、聚丙烯酸鈉乾燥劑塗佈於鰭管式熱交換器，利用乾燥劑吸附空氣中水蒸氣的原理來增強傳統冷卻除濕的效能。本實驗分別以不同進風溫度18°C、25°C、30°C 與固定濕度為85%RH 及風量0.048 m3/s 作為實驗條件，以探討不同乾燥劑熱交換器於不同進風溫度狀態下的除濕量之分析。本研究之結果顯示：在進風溫度25°C 的狀態下，聚丙烯酸鈉熱交換器增強冷卻除濕效能高達64%，矽膠熱交換器也可增強42.48%，取決於乾燥劑本身孔隙容量的不同影響除濕量。並針對加熱再生的熱水溫度70°C 調降為60°C，能有效的脫附乾燥劑內所吸附的水蒸氣，相對再生溫度較於其他高效除濕設備，可減少再生過程時的耗能。本研究發現不同乾燥劑熱交換器最佳冷卻吸附及加熱再生過程中的操作時間，可作為日後除濕設備以自動化控制的時間設定。

This study used desiccants of silica gel and sodium polyacrylatecoated on fin and tube heat exchangers to enhance the absorption of watervapor in the air in comparison to that of conventional cooling and dehumidifyingmethods. The experimental results show that, while the inletair temperature and relative humidity were 25°C and 85%, respectively, thevapor absorbent abilities of the two desiccants were better then those underdifferent inlet air temperatures. The enhancement of the dehumidificationefficiencies of sodium polyacrylate and silica gel were 64% and 42.8%,respectively, in comparison to those of conventional cooling and dehumidificationmethods. The heat exchangers with two desiccant coating were also periodically operated between the absorption and the regenerationprocesses. While the inlet air temperature was 25°C, 60°C hotwater was supplied for the regeneration process in order to reach abalanced state between the amount of absorption vapor and regeneratedvapor. During a cycle of the absorption and regeneration process, theaverage vapor absorption values per unit were 0.0018 gvapor/g × min forsilica gel and 0.004 gvapor/g × min for sodium polyacrylate respectively.For the sodium polyacrylate, the period of absorption process is muchlonger, and the period of regeneration process is also shorter. Thus, thedehumidification efficiency in DCHE possessed better performance.