常用的氟氯碳化物(Freon)冷媒有破壞臭氧層及造成全球暖化效應之虞，天然無機冷媒因此重新受到重視。氨水吸收式冷凍循環系統是以無機且價格低廉的氨作為冷媒，並可使用低階熱源來驅動，從環保及節能的觀點來看，使用吸收式冷凍系統來達到制冷效果的方式，值得做進一步探討。
在氨水吸收式系統中，是利用純氨的蒸發潛熱來吸收熱能以達到制冷效果，而氨氣濃度會直接影響系統整體的效率。由於氨與水具有強親合性，為了獲取高濃度的氨氣，都是藉由體積龐大的蒸餾塔，將氨氣從氨水溶液中精餾出來。本研究嘗試利用3Å分子篩來吸附氨水混合蒸氣中的水汽，以期能得到相同高濃度的氨氣。
本濃縮實驗迴路，可讓氨水蒸氣在高溫高壓的環境下通過分子篩，量測通過分子篩前後之氨氣濃度，以貼近實際氨水吸收式冷凍系統的蒸餾塔運作條件，並嘗試找出不同排列配置之分子篩的吸附情形。從目前的實驗結果得到，在溫度為120℃、壓力為9 atm的條件下，通過分子篩後的氨氣濃度從82%提高至98%左右，顯示分子篩對於分離氨水混合蒸氣有良好的效果。分子篩經脫附後，擷取脫附氣體成分去分析，顯示3Å分子篩在氨水混合氣中，對水氣吸附能力依舊比較強烈。

Many popular halocarbon refrigerants (Freon) had been recognized as the detrimental agents to cause the environmental problems of global warming potential (GWP) and ozone depletion potential (ODP), some existing inorganic refrigerants have thus regained people’s attention to reevaluate their actual value. Aqua-ammonia absorption system using inorganic and inexpensive ammonia as the refrigerant, and using low-grade heat instead of electricity as the power source is actually an ideal chilling system from the view point of environmental protection, and worth to further study its practical role in the refrigeration industry.
The cooling effect of aqua-ammonia absorption system is obtained from the evaporation of liquid ammonia and is closely related to the purity of ammonia which is evaporated. With a strong affinity between water and ammonia, the purification of ammonia is rather difficult. Traditionally, a huge rectifying tower in which many separation and distillation processes are conducted is used to remove the water vapor and increase the ammonia concentration. The bulky system implies an expensive facility and footprint costs and thus reduce its practical value. In this study we try to enrich the ammonia concentration by using 3Å molecular sieves and regenerate molecular sieves，hope that it will have the same performance.
A circulation-loop facility with molecular sieve separation vessel had been completely set-up, the separation process can be performed under the pressure and temperature conditions similar to that of aqua-ammonia absorption system. The test data indicate when the vapor mixtures with 82% ammonia at 120℃ passing through a molecular sieve module, the concentration of ammonia can be increased to 98%.Once the zeolite bed is saturated, the absorbed vapor is desorbed by microwave heating of the bed. This result implies despite the size of water is larger, the sorption of water is much easier than that of ammonia.

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