傳統的氟氯碳化物(Freon)冷媒有著破壞臭氧分子及全球暖化效應之虞，因此天然無機冷媒重新受到重視。氨水吸收式冷凍系統以無機的氨氣為冷媒，並以較低階的熱源來驅動，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，值得做更進一步的探討。
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的效果，而氨氣濃度會直接影響系統的效率。由於氨與水具有強親合性，傳統上為了獲取高濃度的氨氣，都藉由體積相當龐大的蒸餾塔，利用氨與水沸點不同的特性，將氨氣從氨水溶液中精餾出來。本文則嘗試利用3Å分子篩來吸附氨水混合蒸氣中的水汽成分，以期得到高濃度的氨氣。
吾人建立一實驗迴路，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，並嘗試找出分子篩的飽和吸附時間曲線，以及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。

Many freons 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 close 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.
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 molecular sieves module, the concentration of ammonia can be increased to 98%. Thus, it is promising that using molecular sieves to replace the distillation tower in the ammonia-water absorption refrigeration system.

[1]台灣電力公司，『93年負載管理年報』，民國94年。
[2]Kaushik S.C and S.C Bhardwaj, “Theoretical Analysis of Ammonia-Water Absorption Cycles For Refrigeration And Space Conditioning System”, Energy Research, 6, pp.205-235, 1982.
[3]Grossman. G, Michelson. E, “A Modular computer Simulation of Absorption System”, ASHRAE Transactions, 91, Partzb, pp.1808-1827, 1985.
[4]Feng Xu, D. Yogi Goswami, “Thermodynamic properties of ammonia-water mixtures for power-cycle applications”, Energy, 22, pp. 525-536, 1999.
[5]A. De Francisco, R. Illanes, J.L. Torres, “Development and testing of a prototype of low-power water-ammonia absorption equipment for solar energy applications”, Renewable energy, 25, pp.537-544, 2002.
[6]José Fernández-Seara, Jaime Sieres, Manuel Vázquez, “Simultaneous heat and mass transfer of a packed distillation column for ammonia-water absorption refrigeration systems”, International Journal of Thermal Sciences, 41, pp.927-935, 2002.
[7]José Fernández-Seara, Jaime Sieres, “The importance of the ammonia purification process in ammonia-water absorption systems”, Energy Conversion and Management, 47, pp.1975-1987, 2006.
[8]Cronstedt, A.F. Akad. Handl. Stockholm, 18.120, 1756.
[9http://www.siliporite.com/root_ceca/siliporite/gb/static/whatis.htm#zeolites
[10]Ruthven, D.M., Principles of Adsorption and Adsorption Processes, John Wiley, New York, 1984.
[11]Carton, A., González, G., Torre, A.I. and Cabezas, J.L., “Separation of Ethanol-Water Mixtures Using 3A Molecular Sieve”, Journal of Chemical Technology and Biotechnology, 39, pp.125-132, 1987.
[12]Ruthven, D.M., “Zeolites as Selective Adsorbents”, Chemical Engineering Progress, pp.42-50, 1988.
[13]Carmo M.J. and Gubulin J.C., “Ethanol-Water Adsorption on Commercial 3A Zeolites：Kinetic and Thermodynamic Data”, Brazilian Journal of Chemical Engineering, 14, 1997.
[14]B.L. Newalkar, R.V. Jasra, V. Kamath, S.G.T. Bhat, “Sorption of water in aluminophosphate molecular sieve AlPO4-5”, Microporous and Mesoporous Material, 20, pp.129-137, 1998.
[15]J.C. Moïse, J.P. Bellat, A. Méthivier, “Adsorption of water vapor on X and Y zeolites exchanged with barium”, Microporous and Mesoporous Materials, 43, pp.91-101, 2001.
[16]S.W. Rutherford, J.E. Coons, “Adsorption equilibrium and transport kinetics for a range of probe gases in Takeda 3A carbon molecular sieve”, Journal of Colloid and Interface Science, 284, pp.432-439, 2005.
[17]Christèle Beauvais, Anne Boutin, Alain H. Fuchs, “Adsorption of water in zeolite sodium-faujasite A molecular simulation study”, Comptes Rendus Chimie, 8, pp.485-490, 2005.
[18]E. Lalik, R. Mirek, J. Rakoczy, A. Groszek, “Microcalorimetric study of sorption of water and ethanol in zeolites 3A and 5A”, Catalysis, 114, pp.242-247, 2006.
[19]黃秉均，“吸收式冷凍空調系統之分析與設計”，慶齡工業研究中心，研究報告14, 1988.
[20]郭儒家，“吸收式熱泵之種類及其原理”，吸收式冷凍空調技術專輯，中華民國冷凍空調協會, pp.1-6, 1999.12.
[21]Anard G. and Erickson D.C., “Compact sieve-tray distillation column for Ammonia-water absorption heat pump：part1-Design methodology”, ASHRAE Transactions, 105, pp.796-803, 1999.
[22]邱秋燕，“固體吸附原理及其在空調系統之應用”，冷凍空調技術雜誌, 7, pp.64-71, 1990.
[23]陳禮溪，“分子篩應用”，觸媒與製程會刊, 4, pp.67-71, 1995.
[24]J. W. Patrick, Porosity in Carbons, 1st ed., Edward Arnold, 1995.
[25]陳重義，“利用分子篩分離氨水蒸氣於吸收式冷凍系統之可行性研究”，國立成功大學機械工程研究所碩士論文，2005。
[26]D.W. Breck, Zeolite Molecular Sieve, John Wiley and Sons, 1974.
[27http://www.sigmaaldrich.com/Brands/Aldrich/Tech_Bulletins/AL_1/43/Molecular Sieve.html
[28]http://www.hvacr.com.tw/mag/tech/rah02/RAH02-07.cfm
[29]I. Fofana, V. Wasserberg, H. Borsi, “Drying of transformer insulation using zeolite”, IEEE Electrical Insulation Magazine, pp.20-30, 2004.
[30]Emerson, K., R.C. Russo, R.E. Lund and R.V. Thurston, “Aqueous ammonia equilibrium calculations: effect of pH and temperature”, Journal of the Fisheries Research Board of Canada, 32, pp.2379-2383, 1975.
[31]Sander, R. Compilation of Henry’s Law constant for inorganic and organic species of potential importance in environmental chemistry, http://www.mpch-mainz.mpg.de/~sander/res/henry. version 3, 1999.
[32]http://www.ykchem.com/