| Summary: | 碩士 === 國立成功大學 === 機械工程學系碩博士班 === 95 === 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.
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