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很早以前人们就应用氨作为制冷剂,因为氨具有良好的制冷剂应有的特性,如蒸发潜热大、蒸发和冷凝压力适中和价格便宜等,但氨也有不少缺点,如有毒、可燃、在强烈的刺激味,在化学上要腐蚀铜及其合金,压缩后排气温度高达120℃以上等。自从1960年氟利昂问世以后,由于它无色、无臭和无毒的良好化学特性在欧洲、美国和日本等国家纷纷用氟利昂代替氨。除了大型冷藏库外,在中小型制冷装置和空调装置中几乎都使用氟利昂。可是,特定氟利昂(CFC)又具有破坏大气臭氧层的性质,根据1992年保护大
A long time ago, ammonia was used as a refrigerant, because ammonia has good characteristics of refrigerants, such as large latent heat of vaporization, moderate evaporation and condensing pressure and low price, but ammonia has many disadvantages such as toxic, flammable, Strong irritation in the chemical corrosion of copper and its alloys, the exhaust temperature after compression up to 120 ℃ and above. Since the advent of freons in 1960, Freon has been used in place of ammonia in many countries in Europe, the United States and Japan for its good chemical properties of colorless, odorless and non-toxic. In addition to large refrigerators, Freon is used mostly in small and medium-sized refrigerators and air conditioners. However, a particular freon (CFC) has the property of destroying the atmospheric ozone layer. According to 1992,