- 學位論文
氨(R717)/碳氫冷媒(HC)在Cascade低溫冷凍系統之COP效益解析
Performance Analysis of R717/HC Cascade Refrigeration System
摘要
低溫保存冷凍系統在各領域中，扮演著相當重要的角色，由於傳統單段蒸氣壓縮冷凍循環，難以達到所需的低溫要求，必須藉由cascade低溫冷凍系統來達成。近年來環境意識抬頭，因此傳統CFCs、HCFCs和HFCs冷媒已漸不適用，進而尋求新一代的潔淨替代冷媒。在眾多替代冷媒中，自然冷媒具有零ODP、低/零GWP和高效率等優點，故可成為次世代冷凍空調系統冷媒選項之一。氨(R717)和碳氫類(HC)冷媒具有優異的熱物化特性，可應用於各型冷凍空調系統中。 故本論文研究探討分析氨(R717)和碳氫類(HC)冷媒等自然冷媒與傳統R22和R134a冷媒來作為cascade系統冷媒，進一步探討分析及比較6種不同冷媒組在cascade低溫冷凍系統之系統參數與COP性能係數和mH/mL高溫/低溫側冷媒質量流率比之相互影響關係，以期得知cascade低溫冷凍系統參數最佳化及次世代冷媒cascade低溫冷凍系統。
並列摘要
Low-temperature storage refrigeration system is vital for much industry range. The traditional single-stage vapor compressor system is not suitable for low-temperature system; therefore, it should be used through cascade refrigeration system. For many years, as a result of environmental protection issue related global warning and depletion of ozone layer caused by the use of synthetic refrigerants (CFC’s, HCFC’s and HFC’s), the return to the use of harmless natural substances is a must to alternative refrigerants in refrigeration systems. Ammonia (R717) and Hydrocarbon refrigerant have excellent thermodynamic and thermo-physical properties; they can be used in a wide range of refrigeration system. In this paper, a cascade refrigeration system with Ammonia (R717) and Hydrocarbon refrigerant (HC) as working fluids in the low and high temperature stages, respectively, has been analysed and compared with R22 and R134a of traditional refrigerant. Further to research and analysis the relation of COP and mass flow ratio versus operating and design parameters of 6 group’s refrigerant in order to get optimization of parameter and analysed refrigerant in cascade low-temperature refrigeration system.